WorldWideScience

Sample records for zinc chromate induces

  1. Non-Chromate Passivation of Zinc

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Bech-Nielsen, G.

    1993-01-01

    Phos). The treatments are within the same concentration region, and they have a mutual pat-ent pending. Although some tests still need to be conducted, the following aspects are clear at the present time: The general appearance of the passivated zinc surface is very similar to a standard yellow chromate treatment...... successfully. The corrosion resistance against white rust on zinc and zinc alloys is just as good as that of yellow chromate, although the result de-pends on the corrosion test method as well as on the nature of the zinc substrate pas-sivated. The passivation procedure is simply a dip for approxi-mately 2...

  2. Chromate coating of zinc-aluminum plating on mild steel

    International Nuclear Information System (INIS)

    Haque, I.; Khan, A.; Nadeem, A.

    2005-01-01

    The chromate coating on zinc-aluminium deposits has been studied. Zinc-aluminium deposition from non-cyanide bath was carried out at current density 3-3.5 A/dm/sup 2/, plating voltage approx. equal to 1.25 V, temperature 18-20 deg. C, for 15 min. The effect of aluminium chloride on the rest potentials of golden, colorless and non-chromated zinc-aluminium alloy deposits was observed. It was found that rest potential was slightly increased with the increase in the concentration of aluminium chloride, only in the case of golden chromating. The rest potential of colorless chromated zinc-aluminium deposits on mild steel were observed to have no correlation with aluminium chloride concentration. The abrasion resistance of colorless chromating was better than golden chromating. (author)

  3. Investigation of zinc chromatation Part II. Electrochemical impedance techniques

    International Nuclear Information System (INIS)

    Gabrielli, C.; Keddam, M.; Minouflet-Laurent, F.; Ogle, K.; Perrot, H.

    2003-01-01

    A mechanism to explain the formation of a chromate layer on zinc is proposed. It assumes that a ZnO inner film blocks the zinc surface on which the chromate layer grows. This layer has gel-like properties. The diffusion of the protons across the chromate layer and across the solution is supposed to be the kinetically limiting steps. This model was derived and experimentally tested in terms of impedance. The influences of the immersion time, mass transport, and pH of the chromatation solution were examined. A rather good agreement was found between the predictions of the model and the experimental results

  4. Electrical conductivity of chromate conversion coating on electrodeposited zinc

    International Nuclear Information System (INIS)

    Tencer, Michal

    2006-01-01

    For certain applications of galvanized steel protected with conversion coatings it is important that the surface is electrically conductive. This is especially important with mating surfaces for electromagnetic compatibility. This paper addresses electrical conductivity of chromate conversion coatings. A cross-matrix study using different zinc plating techniques by different labs showed that the main deciding factor is the type of zinc-plating bath used rather than the subsequent chromating process. Thus, chromated zinc plate electrodeposited from cyanide baths is non-conductive while that from alkaline (non-cyanide) and acid baths is conductive, even though the plate from all the bath types is conductive before conversion coating. The results correlate well with the microscopic structure of the surfaces as observed with scanning electron microscopy (SEM) and could be further corroborated and rationalized using EDX and Auger spectroscopies

  5. Gamma irradiation effects of 51Cr(III) isotope exchange in doped magnesium chromate - zinc chromate mixtures

    International Nuclear Information System (INIS)

    Mahfouz, R.M.

    1984-01-01

    Gamma irradiation effects of 51 Cr(III) isotope exchange in magnesium chromate - zinc chromate mixtures doped with 51 Cr(III) were investigated. It was found that γ irradiation has an oxidation effect and the percentage of exchanged 51 Cr(VI) increases with the increasing γ-ray dose. The data are explained in terms of mechanistic model involving metal and ligand vacancies exchange and substitution reactions. (author)

  6. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    International Nuclear Information System (INIS)

    Bortolaz de Oliveira, Henrique; Wypych, Fernando

    2016-01-01

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO 4 2− /g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO 4 2− /g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated. - Highlights: • Zinc hydroxide nitrate and Zn/Ni hydroxide nitrate or acetate were synthesized. • The interlayer anions were replaced by chromate anions at pH=8.0. • Only Zn/Ni hydroxide nitrate or acetate have the structure preserved after exchange. • Fast exchange reaction and high capacity of chromate removal were observed. • Magnetic materials were obtained to facilitate the solids removal the from solutions.

  7. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bortolaz de Oliveira, Henrique; Wypych, Fernando, E-mail: wypych@ufpr.br

    2016-11-15

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO{sub 4}{sup 2−}/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO{sub 4}{sup 2−}/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated. - Highlights: • Zinc hydroxide nitrate and Zn/Ni hydroxide nitrate or acetate were synthesized. • The interlayer anions were replaced by chromate anions at pH=8.0. • Only Zn/Ni hydroxide nitrate or acetate have the structure preserved after exchange. • Fast exchange reaction and high capacity of chromate removal were observed. • Magnetic materials were obtained to facilitate the solids removal the from solutions.

  8. Cement-Induced Chromate Occupational Allergic Contact Dermatitis.

    Science.gov (United States)

    Kridin, Khalaf; Bergman, Reuven; Khamaisi, Mogher; Zelber-Sagi, Shira; Weltfriend, Sara

    2016-01-01

    Hexavalent chromium in cement is a common cause of occupational allergic contact dermatitis (OACD). Analysis of patch test data during 1999 to 2013 was done. Patients with cement-induced chromate OACD filled the Dermatology Life Quality Index, graded 1 to 5. Of 4846 consecutive patients who were patch tested, 146 (3%) were chromate-sensitive. Of 46 (31.5%) who presented with chromate OACD, 27 (59%) had cement-induced chromate OACD. The proportion of chromate-sensitive patients with clinically relevant cement exposure increased from 7.7% in 2002 to 2004 to 28.7% in 2011 to 2013 (P = 0.04). The median age of presentation was younger than for other chromate-sensitive patients (32 vs 42 years). Hand eczema (88.9%) was the most frequent clinical presentation. Of the 27 with cement-induced chromate OACD, 21 (77.8%) had ongoing dermatitis at the time of the review. Although 14/27 (51.9%) changed their occupation to avoid exposure to cement, symptoms persisted in 9/14 (64.3%). Prolonged exposure to cement before development of symptoms was associated with chronicity. All the symptomatic patients experienced at least a moderate effect on their quality of life (grade 3 or higher on the Dermatology Life Quality Index). We recommend the adoption of the European legislation in Israel, to reduce the prevalence of chromate OACD from cement.

  9. Stimulus size dependence of hue changes induced by chromatic surrounds.

    Science.gov (United States)

    Kellner, Christian Johannes; Wachtler, Thomas

    2016-03-01

    A chromatic surround induces a change in the perceived hue of a stimulus. This shift in hue depends on the chromatic difference between the stimulus and the surround. We investigated how chromatic induction varies with stimulus size and whether the size dependence depends on the surround hue. Subjects performed asymmetric matching of color stimuli with different sizes in surrounds of different chromaticities. Generally, induced hue shifts decreased with increasing stimulus size. This decrease was quantitatively different for different surround hues. However, when size effects were normalized to an overall induction strength, the chromatic specificity was largely reduced. The separability of inducer chromaticity and stimulus size suggests that these effects are mediated by different neural mechanisms.

  10. Chromatic assimilation unaffected by perceived depth of inducing light.

    Science.gov (United States)

    Shevell, Steven K; Cao, Dingcai

    2004-01-01

    Chromatic assimilation is a shift toward the color of nearby light. Several studies conclude that a neural process contributes to assimilation but the neural locus remains in question. Some studies posit a peripheral process, such as retinal receptive-field organization, while others claim the neural mechanism follows depth perception, figure/ground segregation, or perceptual grouping. The experiments here tested whether assimilation depends on a neural process that follows stereoscopic depth perception. By introducing binocular disparity, the test field judged in color was made to appear in a different depth plane than the light that induced assimilation. The chromaticity and spatial frequency of the inducing light, and the chromaticity of the test light, were varied. Chromatic assimilation was found with all inducing-light sizes and chromaticities, but the magnitude of assimilation did not depend on the perceived relative depth planes of the test and inducing fields. We found no evidence to support the view that chromatic assimilation depends on a neural process that follows binocular combination of the two eyes' signals.

  11. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    Science.gov (United States)

    de Oliveira, Henrique Bortolaz; Wypych, Fernando

    2016-11-01

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

  12. DNA-protein complexes induced by chromate and other carcinogens

    International Nuclear Information System (INIS)

    Costa, M.

    1991-01-01

    DNA-protein complexes induced in intact Chinese hamster ovary cells by chromate have been isolated, analyzed, and compared with those induced by cis-platinum, ultraviolet light, and formaldehyde. Actin has been identified as one of the major proteins complexed to DNA by chromate based upon its molecular weight, isoelectric point, positive reaction with an actin polyclonal antibody, and proteolytic mapping. Chromate and cis-platinum both complex proteins of similar molecular weight and isoelectric point, positive reaction with an actin polyclonal antibody, and proteolytic mapping. Chromate and cis-platinum both complex proteins of similar molecular weight and isoelectric points, and these complexes can be disrupted by chelating agents and sulfhydryl reducing agents, suggesting that the metal itself is participating in binding rather than having a catalytic or indirect role (i.e., oxygen radicals). In contrast, formaldehyde complexed histones to the DNA, and these complexes were not disrupted by chelating or reducing agents. An antiserum raised to chromate-induced DNA-protein complexes reacted primarily with 97,000 kDa protein that did not silver stain. Slot blots, as well as Western blots, were used to detect formation of p97 DNA crosslinks. This protein was complexed to the DNA by all four agents studied

  13. Changes in unique hues induced by chromatic surrounds.

    Science.gov (United States)

    Klauke, Susanne; Wachtler, Thomas

    2016-03-01

    A chromatic surround can have a strong influence on the perceived hue of a stimulus. We investigated whether chromatic induction has similar effects on the perception of colors that appear pure and unmixed (unique red, green, blue, and yellow) as on other colors. Subjects performed unique hue settings of stimuli in isoluminant surrounds of different chromaticities. Compared with the settings in a neutral gray surround, unique hue settings altered systematically with chromatic surrounds. The amount of induced hue shift depended on the difference between stimulus and surround hues, and was similar for unique hue settings as for settings of nonunique hues. Intraindividual variability in unique hue settings was roughly twice as high as for settings obtained in asymmetric matching experiments, which may reflect the presence of a reference stimulus in the matching task. Variabilities were also larger with chromatic surrounds than with neutral gray surrounds, for both unique hue settings and matching of nonunique hues. The results suggest that the neural representations underlying unique hue percepts are influenced by the same neural processing mechanisms as the percepts of other colors.

  14. Toxicokinetics of hexavalent chromium in the rat after intratracheal administration of chromates of different solubilities

    NARCIS (Netherlands)

    Bragt, P.C.; Dura, E.A. van

    1983-01-01

    The kinetics of chromium in the rat after a single intratracheal dose of sodium, zinc or lead 51Cr-chromate have been investigated. Sodium chromate and the less soluble zinc chromate were absorbed into the blood and this resulted in increased excretion of chromium into the urine. The insoluble lead

  15. Effects of chromatic image statistics on illumination induced color differences.

    Science.gov (United States)

    Lucassen, Marcel P; Gevers, Theo; Gijsenij, Arjan; Dekker, Niels

    2013-09-01

    We measure the color fidelity of visual scenes that are rendered under different (simulated) illuminants and shown on a calibrated LCD display. Observers make triad illuminant comparisons involving the renderings from two chromatic test illuminants and one achromatic reference illuminant shown simultaneously. Four chromatic test illuminants are used: two along the daylight locus (yellow and blue), and two perpendicular to it (red and green). The observers select the rendering having the best color fidelity, thereby indirectly judging which of the two test illuminants induces the smallest color differences compared to the reference. Both multicolor test scenes and natural scenes are studied. The multicolor scenes are synthesized and represent ellipsoidal distributions in CIELAB chromaticity space having the same mean chromaticity but different chromatic orientations. We show that, for those distributions, color fidelity is best when the vector of the illuminant change (pointing from neutral to chromatic) is parallel to the major axis of the scene's chromatic distribution. For our selection of natural scenes, which generally have much broader chromatic distributions, we measure a higher color fidelity for the yellow and blue illuminants than for red and green. Scrambled versions of the natural images are also studied to exclude possible semantic effects. We quantitatively predict the average observer response (i.e., the illuminant probability) with four types of models, differing in the extent to which they incorporate information processing by the visual system. Results show different levels of performance for the models, and different levels for the multicolor scenes and the natural scenes. Overall, models based on the scene averaged color difference have the best performance. We discuss how color constancy algorithms may be improved by exploiting knowledge of the chromatic distribution of the visual scene.

  16. Molybdate based passivation of zinc

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Bech-Nielsen, Gregers; Møller, Per

    1997-01-01

    In order to reduce corrosion rates, zinc plated parts are usually chromated. Recently chromates have caused increasingly environmental concern, for both allergic effects among workers touching chro-mated parts and toxic effects on fish, plants and bacteria. A molybdate based alternative has been...

  17. Effect of Kombucha tea on chromate(VI)-induced oxidative stress in albino rats.

    Science.gov (United States)

    Sai Ram, M; Anju, B; Pauline, T; Dipti, P; Kain, A K; Mongia, S S; Sharma, S K; Singh, B; Singh, R; Ilavazhagan, G; Kumar, D; Selvamurthy, W

    2000-07-01

    The effect of Kombucha tea (KT) on oxidative stress induced changes in rats subjected to chromate treatment are reported. KT feeding alone did not show any significant change in malondialdehyde (MDA) and reduced glutathione (GSH) levels, but did enhance humoral response and delayed type of hypersensitivity (DTH) response appreciably over control animals. Chromate treatment significantly enhanced plasma and tissue MDA levels, decreased DTH response considerably, enhanced glutathione peroxidase and catalase activities; however, no change in GSH, superoxide dismutase and antibody titres was noticed. KT feeding completely reversed the chromate-induced changes. These results show that Kombucha tea has potent anti-oxidant and immunopotentiating activities.

  18. Chromate-free Hybrid Coating for Corrosion Protection of Electrogalvanized Steel Sheets

    International Nuclear Information System (INIS)

    Jo, Duhwan; Kwon, Moonjae; Kim, Jongsang

    2012-01-01

    Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances

  19. A "Green" Passivation of Zinc containing surfaces as an alternative to chromate

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel; Møller, Per

    1996-01-01

    comparable performance to chromate in the prohesion test. However no combination in the Molyphos system could compare with the performance of yellow chromate in the neutral salt spray test or humidity test, although Molyphos performs very well in the prohesion test. Welding tests have shown that components...... coated with sealers cause equipment problems during welding....

  20. Chromatic response of polydiacetylene vesicle induced by the permeation of methotrexate.

    Science.gov (United States)

    Shin, Min Jae; Kim, Ye Jin; Kim, Jong-Duk

    2015-07-07

    The noble vesicular system of polydiacetylene showed a red shift using two types of detecting systems. One of the systems involves the absorption of target materials from the outer side of the vesicle, and the other system involves the permeation through the vesicular layers from within the vesicle. The chromatic mixed vesicles of N-(2-aminoethyl)pentacosa-10,12-diynamide (AEPCDA) and dimethyldioctadecylammonium chloride (DODAC) were fabricated by sonication, followed by polymerization by UV irradiation. The stability of monomeric vesicles was observed to increase with the polymerization of the vesicles. Methotrexate was used as a target material. The polymerized mixed vesicles having a blue color were exposed to a concentration gradient of methotrexate, and a red shift was observed indicating the adsorption of methotrexate on the polydiacetylene bilayer. In order to check the chromatic change by the permeation of methotrexate, we separated the vesicle portion, which contained methotrexate inside the vesicle, and checked chromatic change during the permeation of methotrexate through the vesicle. The red shift apparently indicates the disturbance in the bilayer induced by the permeation of methotrexate. The maximum contrast of color appeared at the equal molar ratio of AEPCDA and DODAC, indicating that the formation of flexible and deformable vesicular layers is important for red shift. Therefore, it is hypothesized that the system can be applicable for the chromatic detection of the permeation of methotrexate through the polydiacetylene layer.

  1. Chromatic Derivatives, Chromatic Expansions and Associated Spaces

    OpenAIRE

    Ignjatovic, Aleksandar

    2009-01-01

    This paper presents the basic properties of chromatic derivatives and chromatic expansions and provides an appropriate motivation for introducing these notions. Chromatic derivatives are special, numerically robust linear differential operators which correspond to certain families of orthogonal polynomials. Chromatic expansions are series of the corresponding special functions, which possess the best features of both the Taylor and the Shannon expansions. This makes chromatic derivatives and ...

  2. Corrosion in artificial defects. II. Chromate reactions

    International Nuclear Information System (INIS)

    Furman, S.A.; Scholes, F.H.; Hughes, A.E.; Jamieson, D.N.; Macrae, C.M.; Glenn, A.M.

    2006-01-01

    Artificial defects, in the form of slots, were milled through a chromate-containing protective paint system on AA2024-T3 and exposed to neutral salt spray (NSS). Proton induced X-ray emission (PIXE), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS), electron microprobe analysis (EMPA), and Raman spectroscopy were used to characterise the primer and the alloy surface. Chromate was released by the primer to form a 40 μm depletion zone around the edge of the slot. Within the depletion zone, the chromate was reduced but not completely removed. Chromate was detected in the runoff from the slots and was also found to have reacted with the exposed alloy surface. Chromate was found to react with intermetallic particles, smears formed by the milling process, and pits

  3. Chromaticity

    International Nuclear Information System (INIS)

    Guiducci, S.

    1991-01-01

    A simple calculation of the contribution of quadrupoles and sextupoles to storage ring chromaticity is given. Problems arising from chromaticity carrection are discussed. An accurate derivation of chromaticity formulae for a general bending magnet, exact also for small machines with small radius of curvature, is given

  4. Zinc release contributes to hypoglycemia-induced neuronal death.

    Science.gov (United States)

    Suh, Sang Won; Garnier, Philippe; Aoyama, Koji; Chen, Yongmei; Swanson, Raymond A

    2004-08-01

    Neurons exposed to zinc exhibit activation of poly(ADP-ribose) polymerase-1 (PARP-1), an enzyme that normally participates in DNA repair but promotes cell death when extensively activated. Endogenous, vesicular zinc in brain is released to the extracellular space under conditions causing neuronal depolarization. Here, we used a rat model of insulin-induced hypoglycemia to assess the role of zinc release in PARP-1 activation and neuronal death after severe hypoglycemia. Zinc staining with N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide (TSQ) showed depletion of presynaptic vesicular zinc from hippocampal mossy fiber terminals and accumulation of weakly bound zinc in hippocampal CA1 cell bodies after severe hypoglycemia. Intracerebroventricular injection of the zinc chelator calcium ethylene-diamine tetraacetic acid (CaEDTA) blocked the zinc accumulation and significantly reduced hypoglycemia-induced neuronal death. CaEDTA also attenuated the accumulation of poly(ADP-ribose), the enzymatic product of PARP-1, in hippocampal neurons. These results suggest that zinc translocation is an intermediary step linking hypoglycemia to PARP-1 activation and neuronal death.

  5. Chromaticity measurement via the fourier spectrum of transverse oscillations

    International Nuclear Information System (INIS)

    Xi Yang

    2004-01-01

    Turn-by-turn data from a single BPM includes information on the chromaticity in sidebands displaced above and below the betatron frequency by an amount of the synchrotron frequency. It may be necessary to induce small amplitude synchrotron oscillation by giving the beam a small kick. Power spectrum of the BPM data gives clear chromatic sidebands, and they can be applied to the chromaticity measurement in the Fermilab Booster

  6. Single crystal X-ray structure of the artists’ pigment zinc yellow

    DEFF Research Database (Denmark)

    Simonsen, Kim Pilkjær; Christiansen, Marie Bitsch; Vinum, Morten Gotthold

    2017-01-01

    electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and powder X-ray diffraction (PXRD), showed that the synthesised products and the industrial pigment were identical. Single-crystal X-ray crystallography......The artists’ pigment zinc yellow is in general described as a complex potassium zinc chromate with the empirical formula 4ZnCrO4·K2O·3H2O. Even though the pigment has been in use since the second half of the 19th century also in large-scale industrial applications, the exact structure had hitherto...... been unknown. In this work, zinc yellow was synthesised by precipitation from an aqueous solution of zinc nitrate and potassium chromate under both neutral and basic conditions, and the products were compared with the pigment used in industrial paints. Analyses by Raman microscopy (MRS), scanning...

  7. Chromatic analysis and possible local chromatic correction in RHIC

    International Nuclear Information System (INIS)

    Luo, Y.; Fischer, W.; Gu, X.; Trbojevic, D.

    2011-01-01

    In this article we will answer the following questions for the RHIC polarized proton (p-p) and Au-Au run lattices: (1) what are the sources of second order chromaticities? (2) what is the dependence of second order chromaticity on the on-momentum β-beat? (3) what is the dependence of second order chromaticity on β* at IP6 and IP8? To answer these questions, we use the perturbation theory to numerically calculate the contributions of each quadrupole and sextupole to the first, second, and third order chromaticities. Possible local methods to reduce chromatic effects in RHIC ring are shortly discussed.

  8. Progressive myopia or hyperopia can be induced in chicks and reversed by manipulation of the chromaticity of ambient light.

    Science.gov (United States)

    Foulds, Wallace S; Barathi, Veluchamy A; Luu, Chi D

    2013-12-09

    To determine whether progressive ametropia can be induced in chicks and reversed by manipulation of the chromaticity of ambient light. One-day-old chicks were raised in red light (90% red, 10% yellow-green) or in blue light (85% blue, 15% green) with a 12 hour on/off cycle for 14 to 42 days. Refraction was determined by streak retinoscopy, and by automated infrared photoretinoscopy and ocular biometry by A-scan ultrasonography. Red light induced progressive myopia (mean refraction ± SD at 28 days, -2.83 ± 0.25 diopters [D]). Progressive hyperopia was induced by blue light (mean refraction at 28 days, +4.55 ± 0.21 D). The difference in refraction between the groups was highly significant at P light (-2.21 ± 0.21 D) was reversed to hyperopia (+2.50 ± 0.29 D) by subsequent 21 days of blue light. Hyperopia induced by 21 days of blue light (+4.21 ± 0.19 D) was reversed to myopia (-1.23 ± 0.12 D) by 21 days of red light. Rearing chicks in red light caused progressive myopia, while rearing in blue light caused progressive hyperopia. Light-induced myopia or hyperopia in chicks can be reversed to hyperopia or myopia, respectively, by an alteration in the chromaticity of ambient light. Manipulation of chromaticity may be applicable to the management of human childhood myopia.

  9. Molybdate based Alternatives to Chromating as a Passivation Treatment for Zinc

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Bech-Nielsen, G.; Møller, Per

    1994-01-01

    been developed that can be used to replace chromates in a wide range of applications. The process has been tested in a project set up by the Danish Government in 1989, at the Centre of Advanced Electroplating (CAG)in Denmark. Procedures used for the alternative process are similar to those used...

  10. ZINC-INDUCED HYPERLEPTINEMIA IN RATS RELATED TO THE AMELIORATION OF SUCROSE-INDUCED OBESITY WITH ZINC REPLETION

    International Nuclear Information System (INIS)

    HEIBASHY, M.I.; EL-NAHLA, A.M.; ASHOUR, I.; SALEH, SH.Y.A.

    2008-01-01

    Thirty adult albino rats (Rattus rattus) at 6 weeks of age were divided into three groups (ten for each). The first group was fed a standard laboratory diet for 8 weeks (control). The second group was made obese by giving them 32% sucrose solution in addition to the standard laboratory diet .The third group was received zinc supplementation (50 mg zinc acetate/ litre) with their sucrose solution. Body weight of all rats was measured weekly for 8 weeks. At 14 weeks of age, rats were killed and fasting blood samples were obtained. Serum glucose, insulin, cholesterol, triglyceride, leptin, tumour necrosis factor-α and zinc were measured.Results showed remarkable changes in body weights in sucrose fed rats only when compared to control and supplemented zinc rats group. Serum glucose, insulin, cholesterol and triglycerides were significantly increased in sucrose fed rats than both control and sucrose with zinc group. Serum leptin showed significant increase in sucrose fed rats than control and also showed higher significant value in sucrose fed rats supplemented with zinc comparing with sucrose fed rats and control ones. Tumour necrosis factor-? did not show any significant difference between all groups. Serum zinc concentration was decreased significantly in sucrose fed rats as compared to control. On the other hand, it was increased significantly in sucrose fed rats supplemented with zinc than other both groups. It could be concluded that zinc supplementation induced hyperleptinemia caused ameliorating effects in obese rats

  11. Chromates (3) and chromates (5) of rare earths

    International Nuclear Information System (INIS)

    Suponitskij, Yu.L.

    1986-01-01

    Data on preparation methods, structure and properties of chromates (3, 5) and mixed chromates (3) of rare earths, scandium and yttrium are generalized. Phase diagrams of systems Ln 2 O 3 -Cr 2 O 3 (Ln - rare earths, Sc, Y), chemical and thermodynamic properties of chromates (3, 5), their crystal structure and character of thermal decomposition are considered. Application fields of the compounds mentioned are suggested

  12. Effect of chromate action on morphology of basalt-inhabiting bacteria

    International Nuclear Information System (INIS)

    Lin Zhang; Zhu Ying; Kalabegishvili, Tamaz L.; Tsibakhashvili, Nelly Y.; Holman, Hoi-Ying

    2006-01-01

    Basalt-inhabiting bacteria isolated from polluted basalts have been demonstrated to be able to tolerate moderate to high concentrations of chromium oxyanions such as chromate. Previous results have shown that macromolecules outside the cell wall of bacteria may play an important role in this survival ability. In this paper, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were applied to study the chromate-induced morphological changes in chromate-resistant basalt-inhabiting Arthrobacter K-2 and K-4, which were isolated from the Republic of Georgia. The surfaces of both strains changed in the presence of chromate. TEM thin sections show that chromate stimulates the appearance of bacteria capsular polysaccharide outside the cell wall, although the chromate concentration does not have a strong effect on the capsular thickness. These results, in conjunction with those reported earlier, provide direct evidence to show that capsular polysaccharides of the bacteria play very important role for the reduction and localization of chromate

  13. Chromatic Perceptual Learning but No Category Effects without Linguistic Input.

    Science.gov (United States)

    Grandison, Alexandra; Sowden, Paul T; Drivonikou, Vicky G; Notman, Leslie A; Alexander, Iona; Davies, Ian R L

    2016-01-01

    Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest.

  14. Colchicine induced intraneuronal free zinc accumulation and dentate granule cell degeneration.

    Science.gov (United States)

    Choi, Bo Young; Lee, Bo Eun; Kim, Jin Hee; Kim, Hyun Jung; Sohn, Min; Song, Hong Ki; Chung, Tae Nyoung; Suh, Sang Won

    2014-08-01

    Colchicine has been discovered to inhibit many inflammatory processes such as gout, familial Mediterranean fever, pericarditis and Behcet disease. Other than these beneficial anti-inflammatory effects, colchicine blocks microtubule-assisted axonal transport, which results in the selective loss of dentate granule cells of the hippocampus. The mechanism of the colchicine-induced dentate granule cell death and depletion of mossy fiber terminals still remains unclear. In the present study, we hypothesized that colchicine-induced dentate granule cell death may be caused by accumulation of labile intracellular zinc. 10 μg kg(-1) of colchicine was injected into the adult rat hippocampus and then brain sections were evaluated at 1 day or 1 week later. Neuronal cell death was evaluated by H&E staining or Fluoro-Jade B. Zinc accumulation and vesicular zinc were detected by N-(6-methoxy-8-quinolyl)-para-toluene sulfonamide (TSQ) staining. To test whether an extracellular zinc chelator can prevent this process, CaEDTA was injected into the hippocampus over a 5 min period with colchicine. To test whether other microtubule toxins also produce similar effects as colchicine, vincristine was injected into the hippocampus. The present study found that colchicine injection induced intracellular zinc accumulation in the dentate granule cells and depleted vesicular zinc from mossy fiber terminals. Injection of a zinc chelator, CaEDTA, did not block the zinc accumulation and neuronal death. Vincristine also produced intracellular zinc accumulation and neuronal death. These results suggest that colchicine-induced dentate granule cell death is caused by blocking axonal zinc flow and accumulation of intracellular labile zinc.

  15. Zinc movement in the brain under kainate-induced seizures.

    Science.gov (United States)

    Takeda, Atsushi; Hirate, Maki; Tamano, Haruna; Oku, Naoto

    2003-05-01

    On the basis of the evidence that elimination of 65Zn from the brain of epilepsy (EL) mice is facilitated by induction of seizures, zinc movement in the brain was studied in mice injected with kainate (12 mg/kg x 3), which exhibited status epilepticus within 120 min after the last injection of kainate. Zinc concentrations in the brain were determined 24 h after the last injection of kainate. Zinc concentrations in the hippocampus, amygdala and cerebral cortex, in which zinc-containing glutamatergic neuron terminals exist, were significantly decreased by the treatment with kainate, while that in the cerebellum was not decreased. Timm's stain in the brain was extensively attenuated 24 h after the last injection of kainate. These results indicate that zinc homeostasis in the brain is affected by kainate-induced seizures. In the hippocampus of rats injected with kainate (10 mg/kg), furthermore, the release of zinc and glutamate into the extracellular fluid was studied using in vivo microdialysis. The levels of zinc and glutamate in the perfusate were increased along with seizure severity after injection of kainate. It is likely that zinc concentration in the synaptic vesicles is decreased by the excess excitation of glutamatergic neurons. The present study suggests that the excessive release of zinc and glutamate from the neuron terminals under kainate-induced seizures is associated with the loss of zinc from the brain.

  16. Optimization Of Chromaticity Compensation And Dynamic Aperture In MEIC Collider Rings

    International Nuclear Information System (INIS)

    Lin, Fanglei; Derbenev, Yaroslav; Morozov, Vasiliy; Zhang, Yuhong; Beard, Kevin

    2012-01-01

    The conceptual design of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab relies on an ultra-small beta-star to achieve high luminosities of up to 10 34 cm -2 s -1 . A low-beta insertion for interaction regions unavoidably induces large chromatic effects that demand a proper compensation. The present approach of chromatic compensation in the MEIC collider rings is based on a local correction scheme using two symmetric chromatic compensation blocks that includes families of sextupoles, and are placed in a beam extension area on both sides of a collision point. It can simultaneously compensate the first order chromaticity and chromatic beam smear at the IP without inducing significant second order aberrations. In this paper, we investigate both the momentum acceptance and dynamic aperture in the MEIC ion collider ring by considering the aberration effects up to the third order, such as amplitude dependent tune shift. We also explore the compensation of the third order effects by introducing families of octupoles in the extended beam area.

  17. Single crystal X-ray structure of the artists' pigment zinc yellow

    Science.gov (United States)

    Simonsen, Kim Pilkjær; Christiansen, Marie Bitsch; Vinum, Morten Gotthold; Sanyova, Jana; Bendix, Jesper

    2017-08-01

    The artists' pigment zinc yellow is in general described as a complex potassium zinc chromate with the empirical formula 4ZnCrO4·K2O·3H2O. Even though the pigment has been in use since the second half of the 19th century also in large-scale industrial applications, the exact structure had hitherto been unknown. In this work, zinc yellow was synthesised by precipitation from an aqueous solution of zinc nitrate and potassium chromate under both neutral and basic conditions, and the products were compared with the pigment used in industrial paints. Analyses by Raman microscopy (MRS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and powder X-ray diffraction (PXRD), showed that the synthesised products and the industrial pigment were identical. Single-crystal X-ray crystallography determined the structure of zinc yellow as KZn2(CrO4)2(H2O)(OH) or as KZn2(CrO4)2(H3O2) emphasizing the μ-H3O2- moiety. Notably, the zinc yellow is isostructural to the recently structurally characterized cadmium analog and both belong to the natrochalcite structure type.

  18. Cyclic AMP Pathway Activation and Extracellular Zinc Induce Rapid Intracellular Zinc Mobilization in Candida albicans

    Science.gov (United States)

    Kjellerup, Lasse; Winther, Anne-Marie L.; Wilson, Duncan; Fuglsang, Anja T.

    2018-01-01

    Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen. PMID:29619016

  19. Chemical effects induced by dissolving γ-irradiated alkali halides in aqueous nitrate, permanganate and chromate solutions

    International Nuclear Information System (INIS)

    Phansalkar, V.K.; Bapat, L.; Ravishankar, D.

    1982-01-01

    Dissolution of γ-irradiated alkali halides in aqueous solutions of sodium nitrate, potassium permanganate and potassium chromate at neutral pH induces chemical changes leading to the formation of NO 2 - in nitrate, Mn(IV) and Cr(III) species in permanganate and chromate solutions, respectively. Further, the studies on nitrate and permanganate systems show that the amount of NO 2 - and Mn(IV) formed grows by increasing the dose of γ-irradiation of the salt and the amount of irradiated salt. Moreover, the extent of chemical changes effected by irradiated chlorides has been found to be more than that of bromides. The mesh size of the irradiated salt and the presence of scavengers like I - and methanol in the system, affects the yield of NO 2 - . (author)

  20. Chromatic completion

    OpenAIRE

    Barthel, Tobias

    2014-01-01

    We study the limit of the chromatic tower for not necessarily finite spectra, obtaining a generalization of the chromatic convergence theorem of Hopkins and Ravenel. Moreover, we prove that in general this limit does not coincide with harmonic localization, thereby answering a question of Ravenel's.

  1. Repletion of zinc in zinc-deficient cells strongly up-regulates IL-1β-induced IL-2 production in T-cells.

    Science.gov (United States)

    Daaboul, Doha; Rosenkranz, Eva; Uciechowski, Peter; Rink, Lothar

    2012-10-01

    Mild zinc deficiency in humans negatively affects IL-2 production resulting in declined percentages of cytolytic T cells and decreased NK cell lytic activity, which enhances the susceptibility to infections and malignancies. T-cell activation is critically regulated by zinc and the normal physiological zinc level in T-cells slightly lies below the optimal concentration for T-cell functions. A further reduction in zinc level leads to T-cell dysfunction and autoreactivity, whereas high zinc concentrations (100 μM) were shown to inhibit interleukin-1 (IL-1)-induced IL-1 receptor kinase (IRAK) activation. In this study, we investigated the molecular mechanism by which zinc regulates the IL-1β-induced IL-2 expression in T-cells. Zinc supplementation to zinc-deficient T-cells increased intracellular zinc levels by altering the expression of zinc transporters, particularly Zip10 and Zip12. A zinc signal was observed in the murine T-cell line EL-4 6.1 after 1 h of stimulation with IL-1β, measured by specific zinc sensors FluoZin-3 and ZinPyr-1. This signal is required for the phosphorylation of MAPK p38 and NF-κB subunit p65, which triggers the transcription of IL-2 and strongly increases its production. These results indicate that short-term zinc supplementation to zinc-deficient T-cells leads to a fast rise in zinc levels which subsequently enhance cytokine production. In conclusion, low and excessive zinc levels might be equally problematic for zinc-deficient subjects, and stabilized zinc levels seem to be essential to avoid negative concentration-dependent zinc effects on T-cell activation.

  2. Quantitative mapping of zinc fluxes in the mammalian egg reveals the origin of fertilization-induced zinc sparks

    Energy Technology Data Exchange (ETDEWEB)

    Que, Emily L.; Bleher, Reiner; Duncan, Francesca E.; Kong, Betty Y.; Gleber, Sophie C.; Vogt, Stefan; Chen, Si; Garwin, Seth A.; Bayer, Amanda R.; Dravid, Vinayak P.; Woodruff, Teresa K.; O' Halloran, Thomas V.

    2014-12-15

    Fertilization of a mammalian egg initiates a series of 'zinc sparks' that are necessary to induce the egg-to-embryo transition. Despite the importance of these zinc-efflux events little is known about their origin. To understand the molecular mechanism of the zinc spark we combined four physical approaches that resolve zinc distributions in single cells: a chemical probe for dynamic live-cell fluorescence imaging and a combination of scanning transmission electron microscopy with energy-dispersive spectroscopy, X-ray fluorescence microscopy and three-dimensional elemental tomography for high-resolution elemental mapping. We show that the zinc spark arises from a system of thousands of zinc-loaded vesicles, each of which contains, on average, 10(6) zinc atoms. These vesicles undergo dynamic movement during oocyte maturation and exocytosis at the time of fertilization. The discovery of these vesicles and the demonstration that zinc sparks originate from them provides a quantitative framework for understanding how zinc fluxes regulate cellular processes

  3. Electrochemical assessing corrosion inhibiting effects of zinc aluminum polyphosphate (ZAPP) as a modified zinc phosphate pigment

    International Nuclear Information System (INIS)

    Naderi, R.; Attar, M.M.

    2008-01-01

    Undesirable anti-corrosion performance of zinc phosphate pigment, the classical chromate replacement, has led researchers to take modification into account. Polyphosphate-based anti-corrosion pigments as a result of modification of zinc orthophosphate have been found to function much more efficiently. This study aimed to evaluate performance of steel samples immersed in 3.5% NaCl aqueous solution-containing zinc aluminum polyphosphate (ZAPP) pigment extract compared to those involving conventional zinc phosphate (ZP) pigment extract and also no pigment (blank) using electrochemical tests such as electrochemical impedance spectroscopy (EIS) and linear polarization (LP) as well as surface analysis. Impedance spectra and polarization curves revealed two different trends, showing the superiority of ZAPP pigment. Based on the results of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), presence of a precipitated layer on the surface was confirmed when steel sample was immersed into the solution-containing ZAPP

  4. Chromatic polynomials for simplicial complexes

    DEFF Research Database (Denmark)

    Møller, Jesper Michael; Nord, Gesche

    2016-01-01

    In this note we consider s s -chromatic polynomials for finite simplicial complexes. When s=1 s=1 , the 1 1 -chromatic polynomial is just the usual graph chromatic polynomial of the 1 1 -skeleton. In general, the s s -chromatic polynomial depends on the s s -skeleton and its value at r...

  5. Fluorescent zinc sensor with minimized proton-induced interferences: photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions.

    Science.gov (United States)

    Kwon, Ji Eon; Lee, Sumin; You, Youngmin; Baek, Kyung-Hwa; Ohkubo, Kei; Cho, Jaeheung; Fukuzumi, Shunichi; Shin, Injae; Park, Soo Young; Nam, Wonwoo

    2012-08-20

    A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'-naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a K(d) value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

  6. Arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xi; Zhou, Xixi [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Du, Libo [Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Wenlan [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Liu, Yang [Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Hudson, Laurie G. [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Liu, Ke Jian, E-mail: kliu@salud.unm.edu [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States)

    2014-01-15

    Inhibition of DNA repair is a recognized mechanism for arsenic enhancement of ultraviolet radiation-induced DNA damage and carcinogenesis. Poly(ADP-ribose) polymerase-1 (PARP-1), a zinc finger DNA repair protein, has been identified as a sensitive molecular target for arsenic. The zinc finger domains of PARP-1 protein function as a critical structure in DNA recognition and binding. Since cellular poly(ADP-ribosyl)ation capacity has been positively correlated with zinc status in cells, we hypothesize that arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair. To test this hypothesis, we compared the effects of arsenite exposure with zinc deficiency, created by using the membrane-permeable zinc chelator TPEN, on 8-OHdG formation, PARP-1 activity and zinc binding to PARP-1 in HaCat cells. Our results show that arsenite exposure and zinc deficiency had similar effects on PARP-1 protein, whereas supplemental zinc reversed these effects. To investigate the molecular mechanism of zinc loss induced by arsenite, ICP-AES, near UV spectroscopy, fluorescence, and circular dichroism spectroscopy were utilized to examine arsenite binding and occupation of a peptide representing the first zinc finger of PARP-1. We found that arsenite binding as well as zinc loss altered the conformation of zinc finger structure which functionally leads to PARP-1 inhibition. These findings suggest that arsenite binding to PARP-1 protein created similar adverse biological effects as zinc deficiency, which establishes the molecular mechanism for zinc supplementation as a potentially effective treatment to reverse the detrimental outcomes of arsenic exposure. - Highlights: • Arsenite binding is equivalent to zinc deficiency in reducing PARP-1 function. • Zinc reverses arsenic inhibition of PARP-1 activity and enhancement of DNA damage. • Arsenite binding and zinc loss alter the conformation of zinc finger

  7. Arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair

    International Nuclear Information System (INIS)

    Sun, Xi; Zhou, Xixi; Du, Libo; Liu, Wenlan; Liu, Yang; Hudson, Laurie G.; Liu, Ke Jian

    2014-01-01

    Inhibition of DNA repair is a recognized mechanism for arsenic enhancement of ultraviolet radiation-induced DNA damage and carcinogenesis. Poly(ADP-ribose) polymerase-1 (PARP-1), a zinc finger DNA repair protein, has been identified as a sensitive molecular target for arsenic. The zinc finger domains of PARP-1 protein function as a critical structure in DNA recognition and binding. Since cellular poly(ADP-ribosyl)ation capacity has been positively correlated with zinc status in cells, we hypothesize that arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair. To test this hypothesis, we compared the effects of arsenite exposure with zinc deficiency, created by using the membrane-permeable zinc chelator TPEN, on 8-OHdG formation, PARP-1 activity and zinc binding to PARP-1 in HaCat cells. Our results show that arsenite exposure and zinc deficiency had similar effects on PARP-1 protein, whereas supplemental zinc reversed these effects. To investigate the molecular mechanism of zinc loss induced by arsenite, ICP-AES, near UV spectroscopy, fluorescence, and circular dichroism spectroscopy were utilized to examine arsenite binding and occupation of a peptide representing the first zinc finger of PARP-1. We found that arsenite binding as well as zinc loss altered the conformation of zinc finger structure which functionally leads to PARP-1 inhibition. These findings suggest that arsenite binding to PARP-1 protein created similar adverse biological effects as zinc deficiency, which establishes the molecular mechanism for zinc supplementation as a potentially effective treatment to reverse the detrimental outcomes of arsenic exposure. - Highlights: • Arsenite binding is equivalent to zinc deficiency in reducing PARP-1 function. • Zinc reverses arsenic inhibition of PARP-1 activity and enhancement of DNA damage. • Arsenite binding and zinc loss alter the conformation of zinc finger

  8. Calcium chromate process related investigations

    International Nuclear Information System (INIS)

    Dillard, B.M.

    1979-01-01

    A pilot plant for production of calcium chromate has been scaled up to a small production facility at the General Electric Neutron Devices Department. In preparation for this scale-up, the process and final product were studied in order to evaluate problems not considered previously. The variables and processes studied included: (1) the determination of optimum drying temperature and time for product analysis; (2) the effect of the grade of lime used as the precipitating agent on the purity of the calcium chromate; (3) product purity when calcium chromate is precipitated by the addition of ammonium chromate to slaked lime; (4) the reagents best suited for cleaning calcium chromate spills; and (5) methods for determining hydroxide ion concentration in calcium chromate. The optimum drying time for the product before analysis is four hours at 600 0 C. Gases evolved at various temperatures during the drying process were carbon dioxide and water vapor. Technical grade lime produced calcium chromate of the highest purity. Both nitric and acetic acids were efficient dissolvers of calcium chromate spills. Direct titration of hydroxide ion with sulfuric acid gave an average recovery of 93% for samples spiked with calcium hydroxide. 1 figure, 17 tables

  9. Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

    International Nuclear Information System (INIS)

    Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

    2015-01-01

    The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn 2+ and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase + was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. - Highlights:

  10. Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui, E-mail: Donghuixu007@163.com

    2015-11-15

    The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn{sup 2+} and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase{sup +} was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. - Highlights:

  11. Low chromatic aberration hexapole for molecular state selection

    International Nuclear Information System (INIS)

    Ke, Yi; Deng, Xiao-Bing; Hu, Zhong-Kun

    2016-01-01

    In molecular beam state-selection experiments, the electrostatic hexapole acts as an optical lens, imaging molecules from the source to the focus. The molecular longitudinal velocity spread induces the phenomenon of chromatic aberration, which will reduce the state-selection purity. We propose a scheme which can effectively reduce the chromatic aberration by changing the hexapole voltage operating manner. The hexapole is already charged before molecules arrive at the entrance of the hexapole. When molecules are completely inside the hexapole, the voltage is switched off rapidly at an appropriate time. In this manner, faster molecules travel a longer hexapole focusing region than slower molecules. Therefore the focusing positions of molecules with different velocities become close. Numerical trajectory simulations of molecular state selection are carried out, and the results show that this low chromatic aberration hexapole can significantly improve the state purity from 46.2% to 87.0%. (paper)

  12. Chromatic correction in the SLC bunch length compressors

    International Nuclear Information System (INIS)

    Adolphsen, C.E.; Emma, P.J.; Fieguth, T.H.; Spence, W.L.

    1991-06-01

    The SLC Ring to Linac (RTL) transport lines employ intense bending and strong transverse focusing to produce the momentum compaction needed for bunch length compression prior to S-band acceleration. In the presence of the large rf induced energy spread needed for compression the consequent chromatic effects -- viz. the variation with energy of residual output dispersion and of the RTL transfer matrix, threaten to destroy the small emittances produced by the damping rings. We report on the tuning methods that have been developed and used to implement the sextupole based chromatic correction scheme. 6 refs., 4 figs

  13. Reduction of arsenite-enhanced ultraviolet radiation-induced DNA damage by supplemental zinc

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Karen L.; King, Brenee S.; Sandoval, Monica M.; Liu, Ke Jian; Hudson, Laurie G., E-mail: lhudson@salud.unm.edu

    2013-06-01

    Arsenic is a recognized human carcinogen and there is evidence that arsenic augments the carcinogenicity of DNA damaging agents such as ultraviolet radiation (UVR) thereby acting as a co-carcinogen. Inhibition of DNA repair is one proposed mechanism to account for the co-carcinogenic actions of arsenic. We and others find that arsenite interferes with the function of certain zinc finger DNA repair proteins. Furthermore, we reported that zinc reverses the effects of arsenite in cultured cells and a DNA repair target protein, poly (ADP-ribose) polymerase-1. In order to determine whether zinc ameliorates the effects of arsenite on UVR-induced DNA damage in human keratinocytes and in an in vivo model, normal human epidermal keratinocytes and SKH-1 hairless mice were exposed to arsenite, zinc or both before solar-simulated (ss) UVR exposure. Poly (ADP-ribose) polymerase activity, DNA damage and mutation frequencies at the Hprt locus were measured in each treatment group in normal human keratinocytes. DNA damage was assessed in vivo by immunohistochemical staining of skin sections isolated from SKH-1 hairless mice. Cell-based findings demonstrate that ssUVR-induced DNA damage and mutagenesis are enhanced by arsenite, and supplemental zinc partially reverses the arsenite effect. In vivo studies confirm that zinc supplementation decreases arsenite-enhanced DNA damage in response to ssUVR exposure. From these data we can conclude that zinc offsets the impact of arsenic on ssUVR-stimulated DNA damage in cells and in vivo suggesting that zinc supplementation may provide a strategy to improve DNA repair capacity in arsenic exposed human populations. - Highlights: • Low levels of arsenite enhance UV-induced DNA damage in human keratinocytes. • UV-initiated HPRT mutation frequency is enhanced by arsenite. • Zinc supplementation offsets DNA damage and mutation frequency enhanced by arsenite. • Zinc-dependent reduction of arsenite enhanced DNA damage is confirmed in vivo.

  14. Skew chromaticity

    International Nuclear Information System (INIS)

    Peggs, S.; Dell, G.F.

    1994-01-01

    The on-momentum description of linear coupling between horizontal and vertical betatron motion is extended to include off-momentum particles, introducing a vector quantity called the ''skew chromaticity''. This vector tends to be long in large superconducting storage rings, where it restricts the available working space in the tune plane, and modifies collective effect stability criteria. Skew chromaticity measurements at the Cornell Electron Storage Ring (CESR) and at the Fermilab Tevatron are reported, as well as tracking results from the Relativistic Heavy Ion Collider (RHIC). The observation of anomalous head-tail beam Iowa new the tune diagonal in the Tevatron are explained in terms of the extended theory, including modified criteria for headtail stability. These results are confirmed in head-tail simulations. Sources of skew chromaticity are investigated

  15. Chromaticity compensation scheme for the Main Injector

    International Nuclear Information System (INIS)

    Bogacz, S.A.

    1993-05-01

    The current Main Injector lattice is studied in the context of full chromaticity compensation in the presence of the eddy current, saturation and the end-pack sextupole fields generated by the dipole magnets. Two families of correcting sextupole magnets are placed to compensate these fields and to adjust the chromaticity (in both planes) to some desired value. Variation of the dipole induced sextupole fields with the B-field (changing along a ramp) are modeled according to recent experimental measurements of the Main Injector dipole magnet Analysis of the required sextupole strengths is carried out along two realistic momentum ramps. The results of our calculation give quantitative insight into the requisite performance of the sextupole magnets

  16. Bacterial chromate reduction and product characterization

    International Nuclear Information System (INIS)

    Mehlhorn, R.J.; Buchanan, B.B.; Leighton, T.

    1992-11-01

    Bacillus subtilis reduced hexavalent chromate to trivalent chromium under either aerobic or anaerobic conditions. Reduction of CR(VI) and appearance of extracellular Cr(III) were demonstrated by electron spin resonance and spectrophotometry. Chromate reduction was stimulated more than five-fold by freeze-thawing, indicating that intracellular reductases or chemical reductants reduce chromate more rapidly than do intact cells. Moderately concentrated cells (10% pellet volume after centrifugation) reduced approximately 40 μM chromate/min (2 mg Cr/1-min) when exposed to 100 μM chromate (5 mg Cr/1). Highly concentrated cells (70% pellet volume) reduced more than 99.8% of 2 mM chromate (100 mg Cr/1) within 15 min. This rate of chromate reduction was of the same order of magnitude as the rate of respiration in aerobic cells. A substantial fraction of the reduction product (ca. 75%) was extracellular Cr(M), which could readily be separated from the cells by centrifugation. At high chromate concentrations, some fraction of reduced CR(VI) appeared to be taken up by cells, consistent with a detection of intracellular paramagnetic products. At low chromate concentrations, undefined growth medium alone reduced Cr(VI), but at a slow rate, relative to cells. Under appropriate conditions, B. subtilis appears to be an organism of choice for detoxifying chromate-contaminated soil and water

  17. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Juanjuan; Zhang, Yu [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); Xu, Wentao, E-mail: xuwentaoboy@sina.com [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Luo, YunBo [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Hao, Junran [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); Shen, Xiao Li [The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Yang, Xuan [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); Li, Xiaohong [The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China); Huang, Kunlun, E-mail: hkl009@163.com [Laboratory of Food Safety and Molecular Biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083 (China); The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083 (China)

    2013-04-15

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ{sub m}). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by

  18. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    International Nuclear Information System (INIS)

    Zheng, Juanjuan; Zhang, Yu; Xu, Wentao; Luo, YunBo; Hao, Junran; Shen, Xiao Li; Yang, Xuan; Li, Xiaohong; Huang, Kunlun

    2013-01-01

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ m ). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by OTA in

  19. Chromatic aberrations correction for imaging spectrometer based on acousto-optic tunable filter with two transducers.

    Science.gov (United States)

    Zhao, Huijie; Wang, Ziye; Jia, Guorui; Zhang, Ying; Xu, Zefu

    2017-10-02

    The acousto-optic tunable filter (AOTF) with wide wavelength range and high spectral resolution has long crystal and two transducers. A longer crystal length leads to a bigger chromatic focal shift and the double-transducer arrangement induces angular mutation in diffracted beam, which increase difficulty in longitudinal and lateral chromatic aberration correction respectively. In this study, the two chromatic aberrations are analyzed quantitatively based on an AOTF optical model and a novel catadioptric dual-path configuration is proposed to correct both the chromatic aberrations. The test results exhibit effectiveness of the optical configuration for this type of AOTF-based imaging spectrometer.

  20. Camera processing with chromatic aberration.

    Science.gov (United States)

    Korneliussen, Jan Tore; Hirakawa, Keigo

    2014-10-01

    Since the refractive index of materials commonly used for lens depends on the wavelengths of light, practical camera optics fail to converge light to a single point on an image plane. Known as chromatic aberration, this phenomenon distorts image details by introducing magnification error, defocus blur, and color fringes. Though achromatic and apochromatic lens designs reduce chromatic aberration to a degree, they are complex and expensive and they do not offer a perfect correction. In this paper, we propose a new postcapture processing scheme designed to overcome these problems computationally. Specifically, the proposed solution is comprised of chromatic aberration-tolerant demosaicking algorithm and post-demosaicking chromatic aberration correction. Experiments with simulated and real sensor data verify that the chromatic aberration is effectively corrected.

  1. Solubility of chromate in a hydrated OPC

    International Nuclear Information System (INIS)

    Leisinger, Sabine M.; Bhatnagar, Amit; Lothenbach, Barbara; Johnson, C. Annette

    2014-01-01

    Highlights: • Solid solutions exist between gypsum and calcium chromate. • The cementitious matrix can bind chromate concentrations up to 0.1 mol/kg. • The chromate binding phase in the cementitious matrix is CrO 4 -ettringite. - Abstract: The knowledge of the chromate binding mechanisms is essential for the prediction of the long-term leachability of cement-based solidified waste containing increased chromate concentrations because of its toxicity and high mobility. In this paper pore water concentrations from OPC doped with varying CaCrO 4 concentrations (0.01–0.8 mol/kg), equilibrated for 28 days were reported. It could be shown that the cementitious matrix can bind chromate concentrations up to 0.1 mol/kg and that the chromate solubility limiting phase was CrO 4 -ettringite, while chromate containing AFm (monochromate) was unstable. Comparison with thermodynamic modelling indicated that at lower chromate dosages chromate was mainly bound by CrO 4 -ettringite while at very high dosages also a mixed CaCrO 4 –CaSO 4 ·2H 2 O phase precipitated. Additional experiments indicated a solubility product of 10 −3.66 for CaCrO 4 and verified the solid solution formation with CaSO 4 ·2H 2 O. Leaching tests indicated a strong chromate binding mainly in the pH range 10.5–13.5, while at pH < 10 very little chromate was bound as ettringite, monocarbonate and C–S–H phases were destabilized. Generally the thermodynamic modeling underestimated chromate uptake indicating that an additional chromate binding possibly on C–S–H or on mixed chromate–carbonate–hydroxide AFm phases

  2. Optimizing Chromatic Coupling Measurement in the LHC

    CERN Document Server

    Persson, Tobias

    2016-01-01

    Optimizing chromatic coupling measurement in the LHC Chromatic coupling introduces a dependency of transverse coupling with energy. LHC is equipped with skew sextupoles to compensate the possible adverse effects of chromatic coupling. In 2012 a beam-based correction was calculated and applied successfully for the fist time. However, the method used to reconstruct the chromatic coupling was dependent on stable tunes and equal chromaticities between the horizontal and vertical planes. In this article an improved method to calculate the chromatic coupling without these constraints is presented.

  3. Bounds for the b-Chromatic Number of Subgraphs and Edge-Deleted Subgraphs

    Directory of Open Access Journals (Sweden)

    Francis P.

    2016-11-01

    Full Text Available A b-coloring of a graph G with k colors is a proper coloring of G using k colors in which each color class contains a color dominating vertex, that is, a vertex which has a neighbor in each of the other color classes. The largest positive integer k for which G has a b-coloring using k colors is the b-chromatic number b(G of G. In this paper, we obtain bounds for the b- chromatic number of induced subgraphs in terms of the b-chromatic number of the original graph. This turns out to be a generalization of the result due to R. Balakrishnan et al. [Bounds for the b-chromatic number of G−v, Discrete Appl. Math. 161 (2013 1173-1179]. Also we show that for any connected graph G and any e ∈ E(G, b(G - e ≤ b(G + -2. Further, we determine all graphs which attain the upper bound. Finally, we conclude by finding bound for the b-chromatic number of any subgraph.

  4. The chromatic class and the chromatic number of the planar conjugated triangulation

    OpenAIRE

    Malinina, Natalia

    2013-01-01

    This material is dedicated to the estimation of the chromatic number and chromatic class of the conjugated triangulation (first conversion) and also of the second conversion of the planar triangulation. Also this paper introduces some new hypotheses, which are equivalent to Four Color Problem.

  5. Chromatic interocular-switch rivalry.

    Science.gov (United States)

    Christiansen, Jens H; D'Antona, Anthony D; Shevell, Steven K

    2017-05-01

    Interocular-switch rivalry (also known as stimulus rivalry) is a kind of binocular rivalry in which two rivalrous images are swapped between the eyes several times a second. The result is stable periods of one image and then the other, with stable intervals that span many eye swaps (Logothetis, Leopold, & Sheinberg, 1996). Previous work used this close kin of binocular rivalry with rivalrous forms. Experiments here test whether chromatic interocular-switch rivalry, in which the swapped stimuli differ in only chromaticity, results in slow alternation between two colors. Swapping equiluminant rivalrous chromaticities at 3.75 Hz resulted in slow perceptual color alternation, with one or the other color often continuously visible for two seconds or longer (during which there were 15+ eye swaps). A well-known theory for sustained percepts from interocular-switch rivalry with form is inhibitory competition between binocular neurons driven by monocular neurons with matched orientation tuning in each eye; such binocular neurons would produce a stable response when a given orientation is swapped between the eyes. A similar model can account for the percepts here from chromatic interocular-switch rivalry and is underpinned by the neurophysiological finding that color-preferring binocular neurons are driven by monocular neurons from each eye with well-matched chromatic selectivity (Peirce, Solomon, Forte, & Lennie, 2008). In contrast to chromatic interocular-switch rivalry, luminance interocular-switch rivalry with swapped stimuli that differ in only luminance did not result in slowly alternating percepts of different brightnesses.

  6. Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

    Science.gov (United States)

    Bunnell, Bryan E; Escobar, Jillian F; Bair, Kirsten L; Sutton, Mark D; Crane, John K

    2017-01-01

    Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx) and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

  7. Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Bryan E Bunnell

    Full Text Available Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

  8. Chromatic effects in the superconducting accelerator NUCLOTRON

    International Nuclear Information System (INIS)

    Dinev, D.

    1998-01-01

    A systematic study of the chromatic effects in the superconducting heavy ion synchrotron NUCLOTRON in the JINR, Dubna has been performed. The natural chromaticity has been evaluated taking into account the effect of the dipole magnets. The impact of the systematic and random imperfections in the magnetic field of dipoles on the chromaticity and the dependence of the betatron tunes on the amplitude of oscillations have been investigated. The strengths of the sextupole corrections necessary to cancel the chromaticity have been calculated. The chromatic perturbations have been studied by the means of the Montague chromatic functions (author)

  9. Zinc Improves Cognitive and Neuronal Dysfunction During Aluminium-Induced Neurodegeneration.

    Science.gov (United States)

    Singla, Neha; Dhawan, D K

    2017-01-01

    Metals are considered as important components of a physiologically active cell, and imbalance in their levels can lead to various diseased conditions. Aluminium (Al) is an environmental neurotoxicant, which is etiologically related to several neurodegenerative disorders like Alzheimer's, whereas zinc (Zn) is an essential trace element that regulates a large number of metabolic processes in the brain. The objective of the present study was to understand whether Zn provides any physiological protection during Al-induced neurodegeneration. Male Sprague Dawley rats weighing 140-160 g received either aluminium chloride (AlCl 3 ) orally (100 mg/kg b.wt./day), zinc sulphate (ZnSO 4 ) in drinking water (227 mg/L) or combined treatment of aluminium and zinc for 8 weeks. Al treatment resulted in a significant decline in the cognitive behaviour of rats, whereas zinc supplementation caused an improvement in various neurobehavior parameters. Further, Al exposure decreased (p ≤ 0.001) the levels of neurotransmitters, acetylcholinesterase activity, but increased (p ≤ 0.001) the levels of L-citrulline as well as activities of nitric oxide and monoamine oxidase in the brain. However, zinc administration to Al-treated animals increased the levels of neurotransmitters and regulated the altered activities of brain markers. Western blot of tau, amyloid precursor protein (APP), glial fibrillary acidic protein (GFAP), ubiquitin, α-synuclein and Hsp 70 were also found to be elevated after Al exposure, which however were reversed following Zn treatment. Al treatment also revealed alterations in neurohistoarchitecture in the form of loss of pyramidal and Purkinje cells, which were improved upon zinc co-administration. Therefore, the present study demonstrates that zinc improves cognitive functions by regulating α-synuclein and APP-mediated molecular pathways during aluminium-induced neurodegeneration.

  10. Zinc promotes the death of hypoxic astrocytes by upregulating hypoxia-induced hypoxia-inducible factor-1alpha expression via poly(ADP-ribose) polymerase-1.

    Science.gov (United States)

    Pan, Rong; Chen, Chen; Liu, Wen-Lan; Liu, Ke-Jian

    2013-07-01

    Pathological release of excess zinc ions has been implicated in ischemic brain cell death. However, the underlying mechanisms remain to be elucidated. In stroke, ischemia-induced zinc release and hypoxia-inducible factor-1 (HIF-1) accumulation concurrently occur in the ischemic tissue. The present study tests the hypothesis that the presence of high intracellular zinc concentration is a major cause of modifications to PARP-1 and HIF-1α during hypoxia, which significantly contributes to cell death during ischemia. Primary cortical astrocytes and C8-D1A cells were exposed to different concentrations of zinc chloride. Cell death rate and protein expression of HIF-1 and Poly(ADP-ribose) polymerase (PARP)-1 were examined after 3-h hypoxic treatment. Although 3-h hypoxia or 100 μM of zinc alone did not induce noticeable cytotoxicity, their combination led to a dramatic increase in astrocytic cell death in a zinc-concentration-dependent manner. Exposure of astrocytes to hypoxia for 3 h remarkably increased the levels of intracellular zinc and HIF-1α protein, which was further augmented by added exogenous zinc. Notably, HIF-1α knockdown blocked zinc-induced astrocyte death. Moreover, knockdown of PARP-1, another important protein in the response of hypoxia, attenuated the overexpression of HIF-1α and reduced the cell death rate. Our studies show that zinc promotes hypoxic cell death through overexpression of the hypoxia response factor HIF-1α via the cell fate determine factor PARP-1 modification, which provides a novel mechanism for zinc-mediated ischemic brain injury. © 2013 John Wiley & Sons Ltd.

  11. Sorting chromatic sextupoles for easily and effectively correcting second order chromaticity in the Relativistic Heavy Ion Collider

    International Nuclear Information System (INIS)

    Luo, Y.; Tepikian, S.; Fischer, W.; Robert-Demolaize, G.; Trbojevic, D.

    2009-01-01

    Based on the contributions of the chromatic sextupole families to the half-integer resonance driving terms, we discuss how to sort the chromatic sextupoles in the arcs of the Relativistic Heavy Ion Collider (RHIC) to easily and effectively correct the second order chromaticities. We propose a method with 4 knobs corresponding to 4 pairs of chromatic sextupole families to online correct the second order chromaticities. Numerical simulation justifies this method, showing that this method reduces the unbalance in the correction strengths of sextupole families and avoids the reversal of sextupole polarities. Therefore, this method yields larger dynamic apertures for the proposed RHIC 2009 100GeV polarized proton run lattices

  12. Does the chromatic Mach bands effect exist?

    Science.gov (United States)

    Tsofe, Avital; Spitzer, Hedva; Einav, Shmuel

    2009-06-30

    The achromatic Mach bands effect is a well-known visual illusion, discovered over a hundred years ago. This effect has been investigated thoroughly, mainly for its brightness aspect. The existence of Chromatic Mach bands, however, has been disputed. In recent years it has been reported that Chromatic Mach bands are not perceived under controlled iso-luminance conditions. However, here we show that a variety of Chromatic Mach bands, consisting of chromatic and achromatic regions, separated by a saturation ramp, can be clearly perceived under iso-luminance and iso-brightness conditions. In this study, observers' eye movements were recorded under iso-brightness conditions. Several observers were tested for their ability to perceive the Chromatic Mach bands effect and its magnitude, across different cardinal and non-cardinal Chromatic Mach bands stimuli. A computational model of color adaptation, which predicted color induction and color constancy, successfully predicts this variation of Chromatic Mach bands. This has been tested by measuring the distance of the data points from the "achromatic point" and by calculating the shift of the data points from predicted complementary lines. The results suggest that the Chromatic Mach bands effect is a specific chromatic induction effect.

  13. Psychophysical chromatic mechanisms in macaque monkey.

    Science.gov (United States)

    Stoughton, Cleo M; Lafer-Sousa, Rosa; Gagin, Galina; Conway, Bevil R

    2012-10-24

    Chromatic mechanisms have been studied extensively with psychophysical techniques in humans, but the number and nature of the mechanisms are still controversial. Appeals to monkey neurophysiology are often used to sort out the competing claims and to test hypotheses arising from the experiments in humans, but psychophysical chromatic mechanisms have never been assessed in monkeys. Here we address this issue by measuring color-detection thresholds in monkeys before and after chromatic adaptation, employing a standard approach used to determine chromatic mechanisms in humans. We conducted separate experiments using adaptation configured as either flickering full-field colors or heterochromatic gratings. Full-field colors would favor activity within the visual system at or before the arrival of retinal signals to V1, before the spatial transformation of color signals by the cortex. Conversely, gratings would favor activity within the cortex where neurons are often sensitive to spatial chromatic structure. Detection thresholds were selectively elevated for the colors of full-field adaptation when it modulated along either of the two cardinal chromatic axes that define cone-opponent color space [L vs M or S vs (L + M)], providing evidence for two privileged cardinal chromatic mechanisms implemented early in the visual-processing hierarchy. Adaptation with gratings produced elevated thresholds for colors of the adaptation regardless of its chromatic makeup, suggesting a cortical representation comprised of multiple higher-order mechanisms each selective for a different direction in color space. The results suggest that color is represented by two cardinal channels early in the processing hierarchy and many chromatic channels in brain regions closer to perceptual readout.

  14. Zinc supplementation during pregnancy protects against lipopolysaccharide-induced fetal growth restriction and demise through its anti-inflammatory effect.

    Science.gov (United States)

    Chen, Yuan-Hua; Zhao, Mei; Chen, Xue; Zhang, Ying; Wang, Hua; Huang, Ying-Ying; Wang, Zhen; Zhang, Zhi-Hui; Zhang, Cheng; Xu, De-Xiang

    2012-07-01

    LPS is associated with adverse developmental outcomes, including preterm delivery, fetal death, teratogenicity, and intrauterine growth restriction (IUGR). Previous reports showed that zinc protected against LPS-induced teratogenicity. In the current study, we investigated the effects of zinc supplementation during pregnancy on LPS-induced preterm delivery, fetal death and IUGR. All pregnant mice except controls were i.p. injected with LPS (75 μg/kg) daily from gestational day (GD) 15 to GD17. Some pregnant mice were administered zinc sulfate through drinking water (75 mg elemental Zn per liter) throughout the pregnancy. As expected, an i.p. injection with LPS daily from GD15 to GD17 resulted in 36.4% (4/11) of dams delivered before GD18. In dams that completed the pregnancy, 63.2% of fetuses were dead. Moreover, LPS significantly reduced fetal weight and crown-rump length. Of interest, zinc supplementation during pregnancy protected mice from LPS-induced preterm delivery and fetal death. In addition, zinc supplementation significantly alleviated LPS-induced IUGR and skeletal development retardation. Further experiments showed that zinc supplementation significantly attenuated LPS-induced expression of placental inflammatory cytokines and cyclooxygenase-2. Zinc supplementation also significantly attenuated LPS-induced activation of NF-κB and MAPK signaling in mononuclear sinusoidal trophoblast giant cells of the labyrinth zone. It inhibited LPS-induced placental AKT phosphorylation as well. In conclusion, zinc supplementation during pregnancy protects against LPS-induced fetal growth restriction and demise through its anti-inflammatory effect.

  15. Comparison of various clustered interaction regions with regard to chromatic and dynamic behavior

    International Nuclear Information System (INIS)

    Leemann, B.; Wrulich, A.

    1986-05-01

    Clustered interaction regions for the SSC may be preferable from the viewpoint of costs and operation. In going from distributed to clustered IR's the superperiodicity of the machine is reduced and therefore the number of resonances induced by chromaticity correcting sextupoles is increased. This break in symmetry may cause a reduction in dynamic stability. The chromatic and dynamic behavior of the bare lattice is investigated for various cluster configurations. That means only chromaticity correcting sextupoles have been included and no magnetic imperfection errors have been considered. Then, the dynamic apertures of lattices with various IR clustering schemes are compared when random magnetic imperfections are included

  16. Chromatic polynomials of random graphs

    International Nuclear Information System (INIS)

    Van Bussel, Frank; Fliegner, Denny; Timme, Marc; Ehrlich, Christoph; Stolzenberg, Sebastian

    2010-01-01

    Chromatic polynomials and related graph invariants are central objects in both graph theory and statistical physics. Computational difficulties, however, have so far restricted studies of such polynomials to graphs that were either very small, very sparse or highly structured. Recent algorithmic advances (Timme et al 2009 New J. Phys. 11 023001) now make it possible to compute chromatic polynomials for moderately sized graphs of arbitrary structure and number of edges. Here we present chromatic polynomials of ensembles of random graphs with up to 30 vertices, over the entire range of edge density. We specifically focus on the locations of the zeros of the polynomial in the complex plane. The results indicate that the chromatic zeros of random graphs have a very consistent layout. In particular, the crossing point, the point at which the chromatic zeros with non-zero imaginary part approach the real axis, scales linearly with the average degree over most of the density range. While the scaling laws obtained are purely empirical, if they continue to hold in general there are significant implications: the crossing points of chromatic zeros in the thermodynamic limit separate systems with zero ground state entropy from systems with positive ground state entropy, the latter an exception to the third law of thermodynamics.

  17. Zinc Is Indispensable in Exercise-Induced Cardioprotection against Intermittent Hypoxia-Induced Left Ventricular Function Impairment in Rats.

    Directory of Open Access Journals (Sweden)

    Tsung-I Chen

    Full Text Available In obstructive sleep apnea (OSA, recurrent obstruction of the upper airway leads to intermittent hypoxia (IH during sleep, which can result in impairment of cardiac function. Although exercise can have beneficial effects against IH-induced cardiac dysfunction, the mechanism remains unclear. This study aimed to investigate the interactions of zinc and exercise on IH-triggered left ventricular dysfunction in a rat model that mimics IH in OSA patients. Nine-week-old male Sprague-Dawley rats were randomly assigned to either a control group (CON or to a group receiving 10 weeks of exercise training (EXE. During weeks 9 and 10, half the rats in each group were subjected to IH for 8 h per day for 14 days (IHCON, IHEXE, whereas the remainder continued to breathe room air. Rats within each of the CON, IHCON, EXE, and IHEXE groups were further randomly assigned to receive intraperitoneal injections of either zinc chloride, the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl ethylenediamine (TPEN, or injection vehicle only. IH induced a lower left ventricular fractional shortening, reduced ejection fraction, higher myocardial levels of inflammatory factors, increased levels oxidative stress, and lower levels of antioxidative capacity, all of which were abolished by zinc treatment. IHEXE rats exhibited higher levels of cardiac function and antioxidant capacity and lower levels of inflammatory factors and oxidative stress than IHCON rats; however, IHEXE rats receiving TPEN did not exhibit these better outcomes. In conclusion, zinc is required for protecting against IH-induced LV functional impairment and likely plays a critical role in exercise-induced cardioprotection by exerting a dual antioxidant and anti-inflammatory effect.

  18. Zinc Is Indispensable in Exercise-Induced Cardioprotection against Intermittent Hypoxia-Induced Left Ventricular Function Impairment in Rats

    Science.gov (United States)

    Chen, Michael Yu-Chih

    2016-01-01

    In obstructive sleep apnea (OSA), recurrent obstruction of the upper airway leads to intermittent hypoxia (IH) during sleep, which can result in impairment of cardiac function. Although exercise can have beneficial effects against IH-induced cardiac dysfunction, the mechanism remains unclear. This study aimed to investigate the interactions of zinc and exercise on IH-triggered left ventricular dysfunction in a rat model that mimics IH in OSA patients. Nine-week-old male Sprague-Dawley rats were randomly assigned to either a control group (CON) or to a group receiving 10 weeks of exercise training (EXE). During weeks 9 and 10, half the rats in each group were subjected to IH for 8 h per day for 14 days (IHCON, IHEXE), whereas the remainder continued to breathe room air. Rats within each of the CON, IHCON, EXE, and IHEXE groups were further randomly assigned to receive intraperitoneal injections of either zinc chloride, the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN), or injection vehicle only. IH induced a lower left ventricular fractional shortening, reduced ejection fraction, higher myocardial levels of inflammatory factors, increased levels oxidative stress, and lower levels of antioxidative capacity, all of which were abolished by zinc treatment. IHEXE rats exhibited higher levels of cardiac function and antioxidant capacity and lower levels of inflammatory factors and oxidative stress than IHCON rats; however, IHEXE rats receiving TPEN did not exhibit these better outcomes. In conclusion, zinc is required for protecting against IH-induced LV functional impairment and likely plays a critical role in exercise-induced cardioprotection by exerting a dual antioxidant and anti-inflammatory effect. PMID:27977796

  19. Selective Inducible Nitric Oxide Synthase Inhibitor Reversed Zinc Chloride-Induced Spatial Memory Impairment via Increasing Cholinergic Marker Expression.

    Science.gov (United States)

    Tabrizian, Kaveh; Azami, Kian; Belaran, Maryam; Soodi, Maliheh; Abdi, Khosrou; Fanoudi, Sahar; Sanati, Mehdi; Mottaghi Dastjerdi, Negar; Soltany Rezaee-Rad, Mohammad; Sharifzadeh, Mohammad

    2016-10-01

    Zinc, an essential micronutrient and biochemical element of the human body, plays structural, catalytic, and regulatory roles in numerous physiological functions. In the current study, the effects of a pretraining oral administration of zinc chloride (10, 25, and 50 mg/kg) for 14 consecutive days and post-training bilateral intra-hippocampal infusion of 1400W as a selective inducible nitric oxide synthase (iNOS) inhibitor (10, 50, and 100 μM/side), alone and in combination, on the spatial memory retention in Morris water maze (MWM) were investigated. Animals were trained for 4 days and tested 48 h after completion of training. Also, the molecular effects of these compounds on the expression of choline acetyltransferase (ChAT), as a cholinergic marker in the CA1 region of the hippocampus and medial septal area (MSA), were evaluated. Behavioral and molecular findings of this study showed that a 2-week oral administration of zinc chloride (50 mg/kg) impaired spatial memory retention in MWM and decreased ChAT expression. Immunohistochemical analysis of post-training bilateral intra-hippocampal infusion of 1400W revealed a significant increase in ChAT immunoreactivity. Furthermore, post-training bilateral intra-hippocampal infusion of 1400W into the CA1 region of the hippocampus reversed zinc chloride-induced spatial memory impairment in MWM and significantly increased ChAT expression in comparison with zinc chloride-treated animals. Taken together, these results emphasize the role of selective iNOS inhibitors in reversing zinc chloride-induced spatial memory deficits via modulation of cholinergic marker expression.

  20. Influence of silane films in the zinc coating post-treatment

    International Nuclear Information System (INIS)

    Costa, Marlla Vallerius da; Menezes, Tiago Lemos; Malfatti, Celia de Fraga; Muller, Iduvirges Lourdes; Oliveira, Claudia Trindade; Bonino, Jean-Pierre

    2009-01-01

    The sol-gel process based on silanes precursors appeared in recent years as a strong alternative for post-treatment to provide an optimization of the protective efficacy of zinc. Moreover, this process has been used to replace chemical chromating conversion based on hexavalent chromium. The silane films are hybrid compounds that provide characteristics of both polymeric materials, such as flexibility and functional compatibility, and ceramic materials, such as high strength and durability. The present work aimed to evaluate the influence of silane films obtained by dip-coating, on the characteristics of electrodeposited zinc coatings. The xerogel films showed a homogeneous surface and a better performance on the corrosion resistance than zinc coating without post-treatment, what can be confirmed by the electrochemical impedance results. These tests showed that application of the silane film promotes the occurrence of one more time constant compared to pure zinc system, hindering the corrosion process. (author)

  1. Allergic contact dermatitis induced by zinc pyrithione in shampoo: a case report

    Directory of Open Access Journals (Sweden)

    Chih-Wei Hsieh

    2010-12-01

    Full Text Available Shampoo-induced allergic contact dermatitis is difficult to diagnose clinically because it can involve multiple and variable areas where the shampoo flows. Zinc pyrithione is a common active agent in medicated shampoo that is known to have good anti-dandruff and antifungal effects. Despite its low risk of sensitization, cases of allergic contact dermatitis still occur because of the popularity of such products. We report a 33-year-old man who developed pruritic rash on his scalp, face, neck, and hands after using a new shampoo containing zinc pyrithione. A patch test revealed a positive reaction to zinc pyrithione and personal shampoo containing zinc pyrithione.

  2. On chromatic and geometrical calibration

    DEFF Research Database (Denmark)

    Folm-Hansen, Jørgen

    1999-01-01

    The main subject of the present thesis is different methods for the geometrical and chromatic calibration of cameras in various environments. For the monochromatic issues of the calibration we present the acquisition of monochrome images, the classic monochrome aberrations and the various sources...... the correct interpolation method is described. For the chromatic issues of calibration we present the acquisition of colour and multi-spectral images, the chromatic aberrations and the various lens/camera based non-uniformities of the illumination of the image plane. It is described how the monochromatic...... to design calibration targets for both geometrical and chromatic calibration are described. We present some possible systematical errors on the detection of the objects in the calibration targets, if viewed in a non orthogonal angle, if the intensities are uneven or if the image blurring is uneven. Finally...

  3. Roots of the Chromatic Polynomial

    DEFF Research Database (Denmark)

    Perrett, Thomas

    The chromatic polynomial of a graph G is a univariate polynomial whose evaluation at any positive integer q enumerates the proper q-colourings of G. It was introduced in connection with the famous four colour theorem but has recently found other applications in the field of statistical physics...... extend Thomassen’s technique to the Tutte polynomial and as a consequence, deduce a density result for roots of the Tutte polynomial. This partially answers a conjecture of Jackson and Sokal. Finally, we refocus our attention on the chromatic polynomial and investigate the density of chromatic roots...

  4. Source of second order chromaticity in RHIC

    International Nuclear Information System (INIS)

    Luo, Y.; Gu, X.; Fischer, W.; Trbojevic, D.

    2011-01-01

    In this note we will answer the following questions: (1) what is the source of second order chromaticities in RHIC? (2) what is the dependence of second order chromaticity on the on-momentum β-beat? (3) what is the dependence of second order chromaticity on β* at IP6 and IP8? To answer these questions, we use the perturbation theory to numerically calculate the contributions of each quadrupole and sextupole to the first, second, and third order chromaticities.

  5. Chromatic induction from surrounding stimuli under perceptual suppression.

    Science.gov (United States)

    Horiuchi, Koji; Kuriki, Ichiro; Tokunaga, Rumi; Matsumiya, Kazumichi; Shioiri, Satoshi

    2014-11-01

    The appearance of colors can be affected by their spatiotemporal context. The shift in color appearance according to the surrounding colors is called color induction or chromatic induction; in particular, the shift in opponent color of the surround is called chromatic contrast. To investigate whether chromatic induction occurs even when the chromatic surround is imperceptible, we measured chromatic induction during interocular suppression. A multicolor or uniform color field was presented as the surround stimulus, and a colored continuous flash suppression (CFS) stimulus was presented to the dominant eye of each subject. The subjects were asked to report the appearance of the test field only when the stationary surround stimulus is invisible by interocular suppression with CFS. The resulting shifts in color appearance due to chromatic induction were significant even under the conditions of interocular suppression for all surround stimuli. The magnitude of chromatic induction differed with the surround conditions, and this difference was preserved regardless of the viewing conditions. The chromatic induction effect was reduced by CFS, in proportion to the magnitude of chromatic induction under natural (i.e., no-CFS) viewing conditions. According to an analysis with linear model fitting, we revealed the presence of at least two kinds of subprocesses for chromatic induction that reside at higher and lower levels than the site of interocular suppression. One mechanism yields different degrees of chromatic induction based on the complexity of the surround, which is unaffected by interocular suppression, while the other mechanism changes its output with interocular suppression acting as a gain control. Our results imply that the total chromatic induction effect is achieved via a linear summation of outputs from mechanisms that reside at different levels of visual processing.

  6. Ethambutol-induced toxicity is mediated by zinc and lysosomal membrane permeabilization in cultured retinal cells

    International Nuclear Information System (INIS)

    Chung, Hyewon; Yoon, Young Hee; Hwang, Jung Jin; Cho, Kyung Sook; Koh, Jae Young; Kim, June-Gone

    2009-01-01

    Ethambutol, an efficacious antituberculosis agent, can cause irreversible visual loss in a small but significant fraction of patients. However, the mechanism of ocular toxicity remains to be established. We previously reported that ethambutol caused severe vacuole formation in cultured retinal cells, and that the addition of zinc along with ethambutol aggravated vacuole formation whereas addition of the cell-permeable zinc chelator, N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), reduced vacuole formation. To investigate the origin of vacuoles and to obtain an understanding of drug toxicity, we used cultured primary retinal cells from newborn Sprague-Dawley rats and imaged ethambutol-treated cells stained with FluoZin-3, zinc-specific fluorescent dye, under a confocal microscope. Almost all ethambutol-induced vacuoles contained high levels of labile zinc. Double staining with LysoTracker or MitoTracker revealed that almost all zinc-containing vacuoles were lysosomes and not mitochondria. Intracellular zinc chelation with TPEN markedly blocked both vacuole formation and zinc accumulation in the vacuole. Immunocytochemistry with antibodies to lysosomal-associated membrane protein-2 (LAMP-2) and cathepsin D, an acid lysosomal hydrolase, disclosed lysosomal activation after exposure to ethambutol. Immunoblotting after 12 h exposure to ethambutol showed that cathepsin D was released into the cytosol. In addition, cathepsin inhibitors attenuated retinal cell toxicity induced by ethambutol. This is consistent with characteristics of lysosomal membrane permeabilization (LMP). TPEN also inhibited both lysosomal activation and LMP. Thus, accumulation of zinc in lysosomes, and eventual LMP, may be a key mechanism of ethambutol-induced retinal cell death

  7. Chromaticity correction for the SSC collider rings

    International Nuclear Information System (INIS)

    Sen, T.; Nosochkov, Y.; Pilat, F.; Stiening, R.; Ritson, D.M.

    1993-01-01

    The authors address the issue of correcting higher order chromaticities of the collider with one or more low β insertions. The chromaticity contributed by the interaction regions (IRs) depends crucially on the maximum value of β in the two IRs in a cluster, the phase advance between adjacent interaction points (IPs), and the choice of global tune. They propose a correction scheme in which the linear chromaticity is corrected by a global distribution of sextupoles and the second order chromaticity of each IR is corrected by a more local set of sextupoles. Compared to the case where only the linear chromaticity is corrected, this configuration increases the momentum aperture more than three times and also reduces the β beat by this factor. With this scheme, the tune can be chosen to satisfy other constraints and the two IRs in a cluster can be operated independently at different luminosities without affecting the chromatic properties of the ring

  8. Chromaticity correction for the SSC Collider Rings

    International Nuclear Information System (INIS)

    Sen, T.; Nosochkov, Y.; Pilat, F.; Stiening, R.; Ritson, D.M.

    1993-05-01

    We address the issue of correcting higher order chromaticities of the collider with one or more low β insertions. The chromaticity contributed by the interaction regions (IRS) depends crucially on the maximum value of β in the two IRs in a cluster, the phase advance between adjacent interaction points (IPs), and the choice of global tune. We propose a correction scheme in which the linear chromaticity is corrected by a global distribution of sextupoles and the second order chromaticity of each IR is corrected by a more local set of sextupoles. Compared to the case where only the linear chromaticity is corrected, this configuration increases the momentum aperture more than three times and also reduces the β beat by this factor. With this scheme, the tune can be chosen to satisfy other constraints and the two IRs in a cluster can be operated independently at different luminosities without affecting the chromatic properties of the ring

  9. Three-dimensional shape perception from chromatic orientation flows

    Science.gov (United States)

    Zaidi, Qasim; Li, Andrea

    2010-01-01

    The role of chromatic information in 3-D shape perception is controversial. We resolve this controversy by showing that chromatic orientation flows are sufficient for accurate perception of 3-D shape. Chromatic flows required less cone contrast to convey shape than did achromatic flows, thus ruling out luminance artifacts as a problem. Luminance artifacts were also ruled out by a protanope’s inability to see 3-D shape from chromatic flows. Since chromatic orientation flows can only be extracted from retinal images by neurons that are responsive to color modulations and selective for orientation, the psychophysical results also resolve the controversy over the existence of such neurons. In addition, we show that identification of 3-D shapes from chromatic flows can be masked by luminance modulations, indicating that it is subserved by orientation-tuned neurons sensitive to both chromatic and luminance modulations. PMID:16961963

  10. Low concentrations of zinc in gastric mucosa are associated with increased severity of Helicobacter pylori-induced inflammation.

    Science.gov (United States)

    Sempértegui, Fernando; Díaz, Myriam; Mejía, Ricardo; Rodríguez-Mora, Oswaldo G; Rentería, Edgar; Guarderas, Carlos; Estrella, Bertha; Recalde, Ramiro; Hamer, Davidson H; Reeves, Philip G

    2007-02-01

    Chronic Helicobacter pylori infection is the most common cause of gastric cancer. H. pylori induces oxidative stress while zinc deficiency results in increased sensitivity to it. In Ecuador, the prevalence of gastric cancer and zinc deficiency are high. We hypothesized that zinc deficiency in Ecuadorian people would cause increased H. pylori-induced inflammation in the gastric mucosa associated with lower tissue zinc concentrations. Three hundred and fifty-two patients with dyspepsia underwent endoscopy to obtain gastric mucosa biopsies. Diagnosis of H. pylori infection and its severity, histopathology, mucosal zinc concentration, and inflammation intensity were determined. H. pylori-infected patients with non-atrophic chronic gastritis had lower concentrations of zinc in gastric mucosa than uninfected patients with the same type of gastritis (251.3 +/- 225.3 vs. 426.2 +/- 279.9 ng/mg of protein; p = .016). Considering all patients, the more severe the H. pylori infection, the higher the percentage of subjects with infiltration by polymorphonuclear (PMN) cells (p = .0001). Patients with high PMN infiltration had lower mucosal zinc concentrations than patients with low PMN infiltration (35.2 +/- 20.7 vs. 242.9 +/- 191.8 ng/mg of protein; p = .021). The degree of inflammation in H. pylori-induced gastritis appears to be modulated by gastric tissue zinc concentrations.

  11. The darkening of zinc yellow: XANES speciation of chromium in artist;s paints after light and chemical exposures

    Energy Technology Data Exchange (ETDEWEB)

    Zanella, Luciana; Casadio, Francesca; Gray, Kimberly A.; Warta, Richard; Ma, Qing; Gaillard, Jean-François

    2012-03-14

    The color darkening of selected brushstrokes of the masterpiece A Sunday on La Grande Jatte - 1884 (by Georges Seurat) has been attributed to the alteration of the chromate pigment zinc yellow. The pigment originally displays a bright greenish-yellow color but may undergo, after aging, darkening to a dull, ocher tone. We used XANES to probe the oxidation state of Cr on paint reconstructions, and show that color changes are associated with the reduction of Cr(VI) to Cr(III). Paint mixtures containing the pigment and linseed oil to mimic mixtures used in La Grande Jatte were subjected to artificial aging in the presence of light, SO{sub 2}, and variable air humidity - 50 and 90% relative humidity. High relative humidity led to the largest degree of Cr(VI) reduction whereas low relative humidity promoted light-induced alterations. These results are corroborated by visible reflectance measurements on the same laboratory samples and contribute to a better understanding of the chemical reactivity of chromate pigments, which are present in many historical works of art.

  12. Arsenate and chromate incorporation in schwertmannite

    International Nuclear Information System (INIS)

    Regenspurg, Simona; Peiffer, Stefan

    2005-01-01

    High concentrations of Cr (up to 812 ppm) and As (up to 6740 ppm) were detected in precipitates of the mineral schwertmannite in areas influenced by acid mine drainage. Schwertmannite may act as well as a natural filter for these elements in water as well as their source by releasing the previously bound elements during its dissolution or mineral-transformation. The mechanisms of uptake and potential release for the species arsenate and chromate were investigated by performing synthesis and stability experiments with schwertmannite. Schwertmannite, synthesized in solutions containing arsenate in addition to sulphate, was enriched by up to 10.3 wt% arsenate without detectable structural changes as demonstrated by powder X-ray diffraction (XRD). In contrast to arsenate, a total substitution of sulphate by chromate was possible in sulphate-free solutions. Thereby, the chromate content in schwertmannite could reach 15.3 wt%. To determine the release of oxyanions from schwertmannite over time, synthetic schwertmannite samples containing varying amounts of sulphate, chromate and arsenate were kept at a stable pH of either 2 or 4 over 1 year in suspension. At several time intervals Fe and the oxyanions were measured in solution and alterations of the solid part were observed by XRD and Fourier-Transform infrared (FT-IR) spectroscopy. At pH 2 schwertmannite partly dissolved and the total release of arsenate (24%) was low in contrast to chromate (35.4-57.5%) and sulphate (67-76%). Accordingly, the ionic activity product (log IAP) of arsenated schwertmannite was lowest (13.5), followed by the log IAP for chromated schwertmannite (16.2-18.5) and the log IAP for regular (=non-substituted) schwertmannite (18). At pH 4 schwertmannite transformed to goethite, an effect which occurred at the fastest rate for regular schwertmannite (=arsenate- and chromate-free), followed by chromate and arsenate containing schwertmannite. Both chromate and more evidently arsenate have a

  13. Mechanisms of chromate adsorption on boehmite

    International Nuclear Information System (INIS)

    Johnston, Chad P.; Chrysochoou, Maria

    2015-01-01

    Graphical abstract: - Highlights: • We characterized chromate adsorption on boehmite using molecular modeling and spectroscopy. • Chromate forms a mixture of outer-sphere and inner-sphere complexes. • Inner-sphere complexes are in monodentate and bidentate configuration. - Abstract: Adsorption reactions play an important role in the transport behavior of groundwater contaminants. Molecular-scale information is needed to elucidate the mechanisms by which ions coordinate to soil mineral surfaces. In this study, we characterized the mechanisms of chromate adsorption on boehmite (γ-AlOOH) using a combination of extended X-ray absorption fine structure (EXAFS) measurements, in situ attenuated total reflectance Fourier transform infrared spectroscopy, and quantum chemical calculations. The effects of pH, ionic strength, and aqueous chromate concentration were investigated. Our overall findings were that chromate primarily forms outer-sphere complexes on boehmite over a broad range of pH and aqueous concentrations. Additionally, a small fraction of monodentate and bidentate inner-sphere complexes are present under acidic conditions, as evidenced by two sets of chromate stretching vibrations at approximately 915, 870, and 780 cm −1 , and 940, 890, 850, and 780 cm −1 , respectively. The bidentate complex is supported by a best-fit Cr-Al distance in the EXAFS of 3.2 Å. Results from DFT also support the formation of monodentate and bidentate complexes, which are predicted to results in Gibbs energy changes of −140.4 and −62.5 kJ mol −1 , respectively. These findings are consistent with the intermediate binding strength of chromate with respect to similar oxyanions such as sulfate and selenite. Overall, the surface species identified in this work can be used to develop a more accurate stoichiometric framework in mechanistic adsorption models

  14. The b-chromatic number of power graphs

    Directory of Open Access Journals (Sweden)

    Brice Effantin

    2003-06-01

    Full Text Available The b-chromatic number of a graph G is defined as the maximum number k of colors that can be used to color the vertices of G, such that we obtain a proper coloring and each color i, with 1 ≤ i≤ k, has at least one representant x i adjacent to a vertex of every color j, 1 ≤ j ≠ i ≤ k. In this paper, we discuss the b-chromatic number of some power graphs. We give the exact value of the b-chromatic number of power paths and power complete binary trees, and we bound the b-chromatic number of power cycles.

  15. Zinc triggers microglial activation.

    Science.gov (United States)

    Kauppinen, Tiina M; Higashi, Youichirou; Suh, Sang Won; Escartin, Carole; Nagasawa, Kazuki; Swanson, Raymond A

    2008-05-28

    Microglia are resident immune cells of the CNS. When stimulated by infection, tissue injury, or other signals, microglia assume an activated, "ameboid" morphology and release matrix metalloproteinases, reactive oxygen species, and other proinflammatory factors. This innate immune response augments host defenses, but it can also contribute to neuronal death. Zinc is released by neurons under several conditions in which microglial activation occurs, and zinc chelators can reduce neuronal death in animal models of cerebral ischemia and neurodegenerative disorders. Here, we show that zinc directly triggers microglial activation. Microglia transfected with a nuclear factor-kappaB (NF-kappaB) reporter gene showed a severalfold increase in NF-kappaB activity in response to 30 microm zinc. Cultured mouse microglia exposed to 15-30 microm zinc increased nitric oxide production, increased F4/80 expression, altered cytokine expression, and assumed the activated morphology. Zinc-induced microglial activation was blocked by inhibiting NADPH oxidase, poly(ADP-ribose) polymerase-1 (PARP-1), or NF-kappaB activation. Zinc injected directly into mouse brain induced microglial activation in wild-type mice, but not in mice genetically lacking PARP-1 or NADPH oxidase activity. Endogenous zinc release, induced by cerebral ischemia-reperfusion, likewise induced a robust microglial reaction, and this reaction was suppressed by the zinc chelator CaEDTA. Together, these results suggest that extracellular zinc triggers microglial activation through the sequential activation of NADPH oxidase, PARP-1, and NF-kappaB. These findings identify a novel trigger for microglial activation and a previously unrecognized mechanism by which zinc may contribute to neurological disorders.

  16. High-performance alternating current field-induced chromatic-stable white polymer electroluminescent devices employing a down-conversion layer

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yingdong; Chen, Yonghua; Smith, Gregory M. [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States); Sun, Hengda; Yang, Dezhi [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Nie, Wanyi; Li, Yuan; Huang, Wenxiao [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States); Ma, Dongge [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Carroll, David L., E-mail: carroldl@wfu.edu [Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, NC 27105 (United States)

    2015-05-15

    In this work, a high-performance alternating current (AC) filed-induced chromatic-stable white polymer electroluminescence (WFIPEL) device was fabricated by combining a fluorophor Poly(9,9-dioctylfluorene) (PFO)-based blue device with a yellow down-conversion layer (YAG:Ce). A maximum luminance of this down-conversion FIPEL device achieves 3230 cd m{sup −2}, which is 1.41 times higher than the device without the down-conversion layer. A maximum current efficiency and power efficiency of the down-conversion WFIPEL device reach 19.7 cd A{sup −1} at 3050 cd m{sup −2} and 5.37 lm W{sup −1} at 2310 cd m{sup −2} respectively. To the best of our knowledge, the power efficiency is one of the highest reports for the WFIPEL up to now. Moreover, Commison Internationale de L’Eclairage (CIE) coordinates of (0.28, 0.30) is obtained by adjusting the thickness of the down-conversion layer to 30 μm and it is kept stable over the entire AC-driven voltage range. We believe that this AC-driven, down-conversion, WFIPEL device may offer an easy way towards future flat and flexible lighting sources. - Highlights: • A high-performance AC filed-induced chromatic-stable white polymer electroluminescence (WFIPEL) device was fabricated. • A maximum luminance, current efficiency, and power efficiency achieves 3230 cd m{sup −2}, 19.7 cd A{sup −1}, and 5.37 lm W{sup −1}, respectively. • The power efficiency is one of the highest reports for the WFIPEL up to now. • The EL spectrum kept very stable over the entire AC-driven voltage range.

  17. Oxidising alternative species to chromium VI in zinc-galvanised steel surface treatment. Part 2. An electrochemical study

    International Nuclear Information System (INIS)

    Almeida, E.; Fedrizzi, L.; Diamantinio, T.C.

    1998-01-01

    In the first part of this work, the authors present the main results and conclusions of a morphological and chemical study carried out on zinc conversion layers (ZCLs) obtained with oxidising alternative passivation baths, that includes molybdates, permanganates, van[ates and tungstates. A good chromate-based bath was used as reference. In this second part of the work, the authors present the main results obtained on selected zinc conversion layers (ZCLs), using a.c. electrochemical impedance spectroscopy (EIS). The results obtained were correlated with the morphological and chemical data obtained with the same ZCLs in the first part of this work. Finally, it is concluded that the alternative ZCLs studied, does not seem to be as efficient as that obtained with a chromate-based passivation bath used as reference. It is believed that a better understanding of the mechanisms involved in the ZCL's formation, can be useful for studying, in the very near future, possible synergetic effects between molybdates and other chemical species. (orig.)

  18. Zinc-induced Self-association of Complement C3b and Factor H

    Science.gov (United States)

    Nan, Ruodan; Tetchner, Stuart; Rodriguez, Elizabeth; Pao, Po-Jung; Gor, Jayesh; Lengyel, Imre; Perkins, Stephen J.

    2013-01-01

    The sub-retinal pigment epithelial deposits that are a hallmark of age-related macular degeneration contain both C3b and millimolar levels of zinc. C3 is the central protein of complement, whereas C3u is formed by the spontaneous hydrolysis of the thioester bridge in C3. During activation, C3 is cleaved to form active C3b, then C3b is inactivated by Factor I and Factor H to form the C3c and C3d fragments. The interaction of zinc with C3 was quantified using analytical ultracentrifugation and x-ray scattering. C3, C3u, and C3b associated strongly in >100 μm zinc, whereas C3c and C3d showed weak association. With zinc, C3 forms soluble oligomers, whereas C3u and C3b precipitate. We conclude that the C3, C3u, and C3b association with zinc depended on the relative positions of C3d and C3c in each protein. Computational predictions showed that putative weak zinc binding sites with different capacities exist in all five proteins, in agreement with experiments. Factor H forms large oligomers in >10 μm zinc. In contrast to C3b or Factor H alone, the solubility of the central C3b-Factor H complex was much reduced at 60 μm zinc and even more so at >100 μm zinc. The removal of the C3b-Factor H complex by zinc explains the reduced C3u/C3b inactivation rates by zinc. Zinc-induced precipitation may contribute to the initial development of sub-retinal pigment epithelial deposits in the retina as well as reducing the progression to advanced age-related macular degeneration in higher risk patients. PMID:23661701

  19. Tune and Chromaticity Control During Snapback and Ramp in 2015 LHC Operation

    CERN Document Server

    Schaumann, Michaela; Lamont, Mike; Solfaroli Camillocci, Matteo; Todesco, Ezio; Wenninger, Jorg

    2016-01-01

    Because of current redistribution on the superconducting cables, the harmonic components of the magnetic fields of the superconducting magnets in the Large Hadron Collider (LHC) show decay during the low field injection plateau. This results in tune and chromaticity variations for the beams. In the first few seconds of the ramp the original hysteresis state of the magnetic field is restored - the field snaps back. These fast dynamic field changes lead to strong tune and chromaticity excursions that, if not properly controlled, induce beam losses and potentially trigger a beam dump. A feed-forward system applies predicted corrections during the injection plateau and to the first part of the ramp to avoid violent changes of beam conditions. This paper discusses the snapback of tune and chromaticity as observed in 2015, as well as the control of beam parameters during the ramp. It also evaluates the quality of the applied feed-forward corrections and their reproducibility.

  20. Chromaticity tracking using a phase modulation technique

    International Nuclear Information System (INIS)

    Tan, C.Y.; Fermilab

    2007-01-01

    In the classical chromaticity measurement technique, chromaticity is measured by measuring the change in betatron tune as the RF frequency is varied. This paper will describe a novel way of measuring chromaticity: we will phase modulate the RF with a known sine wave and then phase demodulate the betatron frequency. The result is a line in Fourier space which corresponds to the frequency of our sine wave modulation. The peak of this sine wave is proportional to chromaticity. For this technique to work, a tune tracker PLL system is required because it supplies the betatron carrier frequency. This method has been tested in the Tevatron and we will show the results here

  1. Smarandachely Adjacent-Vertex-Distinguishing Proper Edge Chromatic Number of Cm∨Kn

    OpenAIRE

    Shunqin Liu

    2016-01-01

    According to different conditions, researchers have defined a great deal of coloring problems and the corresponding chromatic numbers. Such as, adjacent-vertex-distinguishing total chromatic number, adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper total chromatic number. And we focus on the smarandachely adjacent-vertex-distinguishing proper edge chromatic...

  2. Understanding and controlling chromaticity shift in LED devices

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Lynn; Mills, Karmann; Lamvik, Michael; Perkins, Curtis; Bobashev, Georgiy; Young, Joseph; Yaga, Robert; Johnson, Cortina

    2017-05-30

    Chromaticity shift in light-emitting diode (LED) devices arises from multiple mechanisms, and at least five different chromaticity shift modes (CSMs) have been identified to date. This paper focuses on the impacts of irreversible phosphor degradation as a cause of chromaticity shifts in LED devices. The nitride phosphors used to produce warm white LEDs are especially vulnerable to degradation due to thermal and chemical effects such as reactions with oxygen and water. As a result, LED devices utilizing these phosphors were found to undergo either a green shift or, less commonly, a red shift depending on the phosphor mix in the LED devices. These types of chromaticity shifts are classified as CSM-2 (green shift) and CSM-5 (red shift). This paper provides an overview of the kinetic processes responsible for green and red chromaticity shifts along with examples from accelerated stress testing of 6” downlights. Both CSMs appear to proceed through analogous mechanisms that are initiated at the surface of the phosphor. A green shift is produced by the surface oxidation of the nitride phosphor that changes the emission profile to lower wavelengths. As the surface oxidation reaction proceeds, reactant limitations slow the rate and bulk oxidation processes become more prevalent. We found that a red chromaticity shift arises from quenching of the green phosphor, also possibly due to surface reactions of oxygen, which shift the emission chromaticity in the red direction. In conclusion, we discuss the implications of these findings on projecting chromaticity.

  3. DESIGN OF A FAST CHROMATICITY JUMP IN RHIC

    International Nuclear Information System (INIS)

    MONTAG, C.; KEWISCH, J.; BRUNO, D.; GANETIS, G.; LOUIE, W.

    2003-01-01

    During transition crossing in the .Relativistic Heavy Ion Collider (RHIC), chromaticities have to change sign. This sign change is partially accomplished by the γ t quadrupole jump; however, the resulting chromaticity jump is only Δξ x = 2.1 in the horizontal and Δξ y = 2.4 in the vertical plane. To increase the jump height, a dedicated chromaticity jump scheme has been designed, consisting of fast power supplies connected to six sextupoles per ring, which is capable of providing a chromaticity jump of Δξ = 6

  4. Measurement and correction of chromaticity in Hefei light source

    International Nuclear Information System (INIS)

    Sun Baogen; Xu Hongliang; He Duohui; Wang Junhua; Lu Ping

    2001-01-01

    The measurement and correction of chromaticity for Hefei light source is introduced. The natural chromaticity is obtained by detecting the variation of the betatron tune with the main dipole field strength. The correction chromaticity is obtained by detecting the variation of the betatron tune with the RF frequency. The theoretic analysis and formula for the two methods is given. The measurement results of chromaticity are given

  5. Chromaticity measurement during beam energy ramp in Indus-2

    International Nuclear Information System (INIS)

    Husain, Riyasat; Vats, D.K.; Ghodke, A.D.

    2013-01-01

    Chromaticity is one of the important parameters of circular accelerators and plays crucial role in its operation. In Indus-2 storage ring the natural chromaticity is -19 and -12 in horizontal and vertical planes respectively. For the good injection at 550 MeV in Indus-2, chromaticity needs to be kept at (+1, +1). The corrected chromaticity does not remain constant during the energy ramp up to 2.5 GeV. We measured Indus-2 storage ring chromaticity by the conventional RF frequency change method. The measurement method and the result of the measurement are reported in this paper. (author)

  6. Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats.

    Science.gov (United States)

    Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

    2015-11-15

    The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague-Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn(2+) and albumin levels (Ptaurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (PTaurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (Ptaurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Effect of impedance and higher order chromaticity on the measurement of linear chromaticity

    OpenAIRE

    V. H. Ranjbar; C. Y. Tan

    2011-01-01

    The combined effect of impedance and higher order chromaticity can act on the beam in a nontrivial manner which can cause a tune shift which depends on the relative momenta with respect to the “on momentum” particle (Δp/p). Experimentally, this tune shift affects the measurement of the linear chromaticity which is traditionally measured with a change of Δp/p. The theory behind this effect will be derived in this paper. Computer simulations and experimental data from the Tevatron will be used ...

  8. Third-rank chromatic aberrations of electron lenses.

    Science.gov (United States)

    Liu, Zhixiong

    2018-02-01

    In this paper the third-rank chromatic aberration coefficients of round electron lenses are analytically derived and numerically calculated by Mathematica. Furthermore, the numerical results are cross-checked by the differential algebraic (DA) method, which verifies that all the formulas for the third-rank chromatic aberration coefficients are completely correct. It is hoped that this work would be helpful for further chromatic aberration correction in electron microscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Chloroquine is a zinc ionophore.

    Directory of Open Access Journals (Sweden)

    Jing Xue

    Full Text Available Chloroquine is an established antimalarial agent that has been recently tested in clinical trials for its anticancer activity. The favorable effect of chloroquine appears to be due to its ability to sensitize cancerous cells to chemotherapy, radiation therapy, and induce apoptosis. The present study investigated the interaction of zinc ions with chloroquine in a human ovarian cancer cell line (A2780. Chloroquine enhanced zinc uptake by A2780 cells in a concentration-dependent manner, as assayed using a fluorescent zinc probe. This enhancement was attenuated by TPEN, a high affinity metal-binding compound, indicating the specificity of the zinc uptake. Furthermore, addition of copper or iron ions had no effect on chloroquine-induced zinc uptake. Fluorescent microscopic examination of intracellular zinc distribution demonstrated that free zinc ions are more concentrated in the lysosomes after addition of chloroquine, which is consistent with previous reports showing that chloroquine inhibits lysosome function. The combination of chloroquine with zinc enhanced chloroquine's cytotoxicity and induced apoptosis in A2780 cells. Thus chloroquine is a zinc ionophore, a property that may contribute to chloroquine's anticancer activity.

  10. Prenatal zinc prevents communication impairments and BDNF disturbance in a rat model of autism induced by prenatal lipopolysaccharide exposure.

    Science.gov (United States)

    Kirsten, Thiago B; Queiroz-Hazarbassanov, Nicolle; Bernardi, Maria M; Felicio, Luciano F

    2015-06-01

    Aims: Previous investigations by our group have shown that prenatal exposure to lipopolysaccharide (LPS),which mimics infections by Gram-negative bacteria, induced autistic-like behavior. No effective treatment yet exists for autism. Therefore, we used our rat model to test a possible treatment for autism.We selected zinc as the prenatal treatment to prevent or ease the impairments induced by LPS because LPS induces hypozincaemia.Materials and methods:We evaluated the effects of LPS and zinc on female reproductive performance. Communication,which is impaired in autism,was tested in pups by ultrasonic vocalizations. Plasma levels of brain-derived neurotrophic factor (BDNF) were determined because it has been considered an autism important biomarker.Key findings: Prenatal LPS exposure reduced offspring number and treatment with zinc prevented this reduction.Moreover, pups that were prenatally exposed to LPS spent longer periods without calling their mothers, and posttreatment with zinc prevented this impairment induced by LPS to the same levels as controls. Prenatal LPS also increased BDNF levels in adult offspring, and posttreatment with zinc reduced the elevation of BDNF to the same levels as controls.Significance: BDNF hyperactivity was also found in several studies of autistic patients. Together with our previous studies, our model of prenatal LPS induced autistic-like behavioral, brain, and immune disturbances. This suggests that it is a valid rat model of autism. Prenatal zinc prevented reproductive, communication, and BDNF impairments.The present study revealed a potential beneficial effect of prenatal zinc administration for the prevention of autism with regard to the BDNF pathway.

  11. Investigation of cleaning reagents for calcium chromate spills

    International Nuclear Information System (INIS)

    Dillard, B.M.

    1979-01-01

    Cleaning of calcium chromate spills can be a problem due to the insolubility of the material and the corrosiveness of several possible cleaning agents on the stainless steel equipment. Because of OSHA Standards for Cr(VI) exposure, it is necessary to remove spills as efficiently as possible in order to prevent the contaminant from becoming airborne. This study involved the comparison of several possible cleaning agents by studying the solubility of calcium chromate in each reagent. Two general types of reagents for dissolution of calcium chromate were investigated; those which act by conversion of the insoluble calcium chromate to a more soluble salt and to H 2 CrO 4 , and those which appear to act as complexing agents and thereby dissolve the calcium chromate. The most efficient of the reagents investigated was hydrochloric acid. However, even dilute solutions of halide acids destroy passivity of stainless steel causing pitting and stress-corrosion. Acetic acid and nitric acid were somewhat less efficient than hydrochloric acid in dissolving calcium chromate. However, both reagents are noncorrosive with stainless steel, nitric acid tending to favor passivity of the materials. Therefore, it is recommended that dilute solutions of either of these two acids be used for removal of calcium chromate spills in conjunction with mechanical methods that might be necessary, depending on the magnitude of the spill

  12. Effect of impedance and higher order chromaticity on the measurement of linear chromaticity

    Directory of Open Access Journals (Sweden)

    V. H. Ranjbar

    2011-08-01

    Full Text Available The combined effect of impedance and higher order chromaticity can act on the beam in a nontrivial manner which can cause a tune shift which depends on the relative momenta with respect to the “on momentum” particle (Δp/p. Experimentally, this tune shift affects the measurement of the linear chromaticity which is traditionally measured with a change of Δp/p. The theory behind this effect will be derived in this paper. Computer simulations and experimental data from the Tevatron will be used to support the theory.

  13. A novel mechanism for the pyruvate protection against zinc-induced cytotoxicity: mediation by the chelating effect of citrate and isocitrate.

    Science.gov (United States)

    Sul, Jee-Won; Kim, Tae-Youn; Yoo, Hyun Ju; Kim, Jean; Suh, Young-Ah; Hwang, Jung Jin; Koh, Jae-Young

    2016-08-01

    Intracellular accumulation of free zinc contributes to neuronal death in brain injuries such as ischemia and epilepsy. Pyruvate, a glucose metabolite, has been shown to block zinc neurotoxicity. However, it is largely unknown how pyruvate shows such a selective and remarkable protective effect. In this study, we sought to find a plausible mechanism of pyruvate protection against zinc toxicity. Pyruvate almost completely blocked cortical neuronal death induced by zinc, yet showed no protective effects against death induced by calcium (ionomycin, NMDA) or ferrous iron. Of the TCA cycle intermediates, citrate, isocitrate, and to a lesser extent oxaloacetate, protected against zinc toxicity. We then noted with LC-MS/MS assay that exposure to pyruvate, and to a lesser degree oxaloacetate, increased levels of citrate and isocitrate, which are known zinc chelators. While pyruvate added only during zinc exposure did not reduce zinc toxicity, citrate and isocitrate added only during zinc exposure, as did extracellular zinc chelator CaEDTA, completely blocked it. Furthermore, addition of pyruvate after zinc exposure substantially reduced intracellular zinc levels. Our results suggest that the remarkable protective effect of pyruvate against zinc cytotoxicity may be mediated indirectly by the accumulation of intracellular citrate and isocitrate, which act as intracellular zinc chelators.

  14. On the chromatic number of general Kneser hypergraphs

    DEFF Research Database (Denmark)

    Alishahi, Meysam; Hajiabolhassan, Hossein

    2015-01-01

    In a break-through paper, Lovász [20] determined the chromatic number of Kneser graphs. This was improved by Schrijver [27], by introducing the Schrijver subgraphs of Kneser graphs and showing that their chromatic number is the same as that of Kneser graphs. Alon, Frankl, and Lovász [2] extended...... their chromatic number as an approach to a supposition of Ziegler [35] and a conjecture of Alon, Drewnowski, and Łuczak [3]. In this work, our second main result is to improve this by computing the chromatic number of a large family of Schrijver hypergraphs. Our last main result is to prove the existence...... of a completely multicolored complete bipartite graph in every coloring of a graph which extends a result of Simonyi and Tardos [29].The first two results are proved using a new improvement of the Dol'nikov-Kříž [7,18] bound on the chromatic number of general Kneser hypergraphs....

  15. Determination of percent calcium carbonate in calcium chromate

    International Nuclear Information System (INIS)

    Middleton, H.W.

    1979-01-01

    The precision, accuracy and reliability of the macro-combustion method is superior to the Knorr alkalimetric method, and it is faster. It also significantly reduces the calcium chromate waste accrual problem. The macro-combustion method has been adopted as the official method for determination of percent calcium carbonate in thermal battery grade anhydrous calcium chromate and percent calcium carbonate in quicklime used in the production of calcium chromate. The apparatus and procedure can be used to measure the percent carbonate in inorganic materials other than calcium chromate. With simple modifications in the basic apparatus and procedure, the percent carbon and hydrogen can be measured in many organic material, including polymers and polymeric formulations. 5 figures, 5 tables

  16. Chromate Binding and Removal by the Molybdate-Binding Protein ModA.

    Science.gov (United States)

    Karpus, Jason; Bosscher, Michael; Ajiboye, Ifedayo; Zhang, Liang; He, Chuan

    2017-04-04

    Effective and cheap methods and techniques for the safe removal of hexavalent chromate from the environment are in increasingly high demand. High concentrations of hexavalent chromate have been shown to have numerous harmful effects on human biology. We show that the E. coli molybdate-binding protein ModA is a genetically encoded tool capable of removing chromate from aqueous solutions. Although previously reported to not bind chromate, we show that ModA binds chromate tightly and is capable of removing chromate to levels well below current US federal standards. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Effect of red maca (Lepidium meyenii) on prostate zinc levels in rats with testosterone-induced prostatic hyperplasia.

    Science.gov (United States)

    Gonzales, C; Leiva-Revilla, J; Rubio, J; Gasco, M; Gonzales, G F

    2012-05-01

    Lepidium meyenii (maca) is a plant that grows exclusively above 4000 m in the Peruvian central Andes. Red maca (RM) extract significantly reduced prostate size in rats with benign prostatic hyperplasia (BPH) induced by testosterone enanthate (TE). Zinc is an important regulator of prostate function. This study aimed to determine the effect of RM on prostate zinc levels in rats with BPH induced by TE. Also, the study attempted to determine the best marker for the effect of RM on sex accessory glands. Rats treated with RM extract from day 1 to day 14 reversed the effect of TE administration on prostate weight and zinc levels. However, RM administered from day 7 to day 14 did not reduce the effect of TE on all studied variables. Finasteride (FN) reduced prostate, seminal vesicle and preputial gland weights in rats treated with TE. Although RM and FN reduced prostate zinc levels, the greatest effect was observed in TE-treated rats with RM from day 1 to day 14. In addition, prostate weight and zinc levels showed the higher diagnosis values than preputial and seminal vesicle weights. In conclusion, RM administered from day 1 to day 14 reduced prostate size and zinc levels in rats where prostatic hyperplasia was induced with TE. Also, this experimental model could be used as accurately assay to determine the effect of maca obtained under different conditions and/or the effect of different products based on maca. © 2011 Blackwell Verlag GmbH.

  18. Alterations in protein kinase C activity and processing during zinc-deficiency-induced cell death.

    Science.gov (United States)

    Chou, Susan S; Clegg, Michael S; Momma, Tony Y; Niles, Brad J; Duffy, Jodie Y; Daston, George P; Keen, Carl L

    2004-10-01

    Protein kinases C (PKCs) are a family of serine/threonine kinases that are critical for signal transduction pathways involved in growth, differentiation and cell death. All PKC isoforms have four conserved domains, C1-C4. The C1 domain contains cysteine-rich finger-like motifs, which bind two zinc atoms. The zinc-finger motifs modulate diacylglycerol binding; thus, intracellular zinc concentrations could influence the activity and localization of PKC family members. 3T3 cells were cultured in zinc-deficient or zinc-supplemented medium for up to 32 h. Cells cultured in zinc-deficient medium had decreased zinc content, lowered cytosolic classical PKC activity, increased caspase-3 processing and activity, and reduced cell number. Zinc-deficient cytosols had decreased activity and expression levels of PKC-alpha, whereas PKC-alpha phosphorylation was not altered. Inhibition of PKC-alpha with Gö6976 had no effect on cell number in the zinc-deficient group. Proteolysis of the novel PKC family member, PKC-delta, to its 40-kDa catalytic fragment occurred in cells cultured in the zinc-deficient medium. Occurrence of the PKC-delta fragment in mitochondria was co-incident with caspase-3 activation. Addition of the PKC-delta inhibitor, rottlerin, or zinc to deficient medium reduced or eliminated proteolysis of PKC-delta, activated caspase-3 and restored cell number. Inhibition of caspase-3 processing by Z-DQMD-FMK (Z-Asp-Gln-Met-Asp-fluoromethylketone) did not restore cell number in the zinc-deficient group, but resulted in processing of full-length PKC-delta to a 56-kDa fragment. These results support the concept that intracellular zinc concentrations influence PKC activity and processing, and that zinc-deficiency-induced apoptosis occurs in part through PKC-dependent pathways.

  19. Thermal reactions of some calcium, strontium, and barium chromates

    International Nuclear Information System (INIS)

    Piekarska-Piesse, B.; Gontarz, Z.; Ostrowski, A.; Kucharski, R.

    2000-01-01

    Thermal decomposition of calcium chromates and solid state reactions of barium and strontium chromates(VI) with barium and strontium hydroxides and carbonates, as well as the reduction of chromates by carbon and hydrogen, have been investigated. The mechanisms of individual stages of the thermal decomposition have been proposed on the basis of morphological classification. (author)

  20. Chromate conversion coatings and their current application

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-04-01

    Full Text Available This paper describes formation, composition and possible production technologies of application chromate coatings. Summation of common examples of applications of these coatings in corrosion protection of metals and alloys is provided. Individual chromate coatings are divided by their dominant anions either with CrVI or CrIII. Restrictions of chromate coatings with dominantly CrVI and related toxicity of hexavalent chromium is discussed in detail. In conclusion, examples of both chromium and other, alternative coatings are summed up. Application of these coatings as a protection for concrete hot-dip galvanized reinforcement is also reviewed.

  1. Chromaticity and Glossiness of Gold, Silver, and Bronze Colors

    Directory of Open Access Journals (Sweden)

    Tomohisa Matsumoto

    2011-05-01

    Full Text Available Appearance of metallic colors, such as gold, silver and bronze, depends on chromaticity and glossiness of a surface. We aim to obtain the chromaticity region of gold, silver, and bronze by using CG simulated surfaces with various glossiness. The physical glossiness was defined by the intensity ratio of specular reflectance of the surface stimulus. The observer estimated degree of perceived glossiness, and also degree of gold, silver, or bronze appearance of the stimulus with a physical glossiness and a chromaticity. The results showed that the stimulus began to appear gold, silver or bronze at a certain chromaticity point only when the stimulus had glossiness. The chromaticity range, where gold, silver and bronze colors were observed, expanded as the degree of glossiness increased. Furthermore the ratio of the degree of gold, silver or bronze colors to that of glossiness of the stimulus was found to be different among the chromaticity points of the stimulus. This ratio was highest with highly saturated stimuli for gold and bronze colors, and with achromatic stimuli for silver color.

  2. Zinc regulates Nox1 expression through a NF-κB and mitochondrial ROS dependent mechanism to induce senescence of vascular smooth muscle cells.

    Science.gov (United States)

    Salazar, G; Huang, J; Feresin, R G; Zhao, Y; Griendling, K K

    2017-07-01

    The role of oxidative stress and inflammation in the development and progression of cardiovascular diseases (CVD) is well established. Increases in oxidative stress can further exacerbate the inflammatory response and lead to cellular senescence. We previously reported that angiotensin II (Ang II) and zinc increase reactive oxygen species (ROS) and cause senescence of vascular smooth muscle cells (VSMCs) and that senescence induced by Ang II is a zinc-dependent process. Zinc stimulated NADPH oxidase (Nox) activity; however, the role of Nox isoforms in zinc effects was not determined. Here, we show that downregulation of Nox1, but not Nox4, by siRNA prevented both Ang II- and zinc-induced senescence in VSMCs. On the other hand, overexpression of Nox1 induced senescence, which was associated with reduced proliferation, reduced expression of telomerase and increased DNA damage. Zinc increased Nox1 protein expression, which was inhibited by chelation of zinc with TPEN and by overexpression of the zinc exporters ZnT3 and ZnT10. These transporters work to reduce cytosolic zinc, suggesting that increased cytosolic zinc mediates Nox1 upregulation. Other metals including copper, iron, cobalt and manganese failed to upregulate Nox1, suggesting that this pathway is zinc specific. Nox1 upregulation was inhibited by actinomycin D (ACD), an inhibitor of transcription, by inhibition of NF-κB, a known Nox1 transcriptional regulator and by N-acetyl cysteine (NAC) and MitoTEMPO, suggesting that NF-κB and mitochondrial ROS mediate zinc effects. Supporting this idea, we found that zinc increased NF-κB activation in the cytosol, stimulated the translocation of the p65 subunit to the nucleus, and that zinc accumulated in mitochondria increasing mitochondrial ROS, measured using MitoSox. Further, zinc-induced senescence was reduced by inhibition of NF-κB or reduction of mitochondrial ROS with MitoTEMPO. NF-κB activity was also reduced by MitoTEMPO, suggesting that mitochondrial ROS

  3. Symplectic maps and chromatic optics in particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai

    2015-10-11

    We have applied the nonlinear map method to comprehensively characterize the chromatic optics in particle accelerators. Our approach is built on the foundation of symplectic transfer maps of magnetic elements. The chromatic lattice parameters can be transported from one element to another by the maps. We introduce a Jacobian operator that provides an intrinsic linkage between the maps and the matrix with parameter dependence. The link allows us to directly apply the formulation of the linear optics to compute the chromatic lattice parameters. As an illustration, we analyze an alternating-gradient cell with nonlinear sextupoles, octupoles, and decapoles and derive analytically their settings for the local chromatic compensation. As a result, the cell becomes nearly perfect up to the third-order of the momentum deviation.

  4. Connections between the matching and chromatic polynomials

    Directory of Open Access Journals (Sweden)

    E. J. Farrell

    1992-01-01

    Full Text Available The main results established are (i a connection between the matching and chromatic polynomials and (ii a formula for the matching polynomial of a general complement of a subgraph of a graph. Some deductions on matching and chromatic equivalence and uniqueness are made.

  5. Protection against T1DM-Induced Bone Loss by Zinc Supplementation: Biomechanical, Histomorphometric, and Molecular Analyses in STZ-Induced Diabetic Rats.

    Directory of Open Access Journals (Sweden)

    Raul Hernandes Bortolin

    Full Text Available Several studies have established an association between diabetes and alterations in bone metabolism; however, the underlying mechanism is not well established. Although zinc is recognized as a potential preventive agent against diabetes-induced bone loss, there is no evidence demonstrating its effect in chronic diabetic conditions. This study evaluated the effects of zinc supplementation in a chronic (90 days type 1 diabetes-induced bone-loss model. Male Wistar rats were distributed in three groups: control, type 1 diabetes mellitus (T1DM, and T1DM plus zinc supplementation (T1DMS. Serum biochemical analysis; tibia histomorphometric, biomechanical, and collagen-content analyses; and femur mRNA expression were evaluated. Relative to T1DM, the zinc-supplemented group showed increased histomorphometric parameters such as TbWi and BAr and decreased TbSp, increased biomechanical parameters (maximum load, stiffness, ultimate strain, and Young's modulus, and increased type I collagen content. Interestingly, similar values for these parameters were observed between the T1DMS and control groups. These results demonstrate the protective effect of zinc on the maintenance of bone strength and flexibility. In addition, downregulation of OPG, COL1A, and MMP-9 genes was observed in T1DMS, and the anabolic effects of zinc were evidenced by increased OC expression and serum ALP activity, both related to osteoblastogenesis, demonstrating a positive effect on bone formation. In contrast, T1DM showed excessive bone loss, observed through reduced histomorphometric and biomechanical parameters, characterizing diabetes-associated bone loss. The bone loss was also observed through upregulation of OPG, COL1A, and MMP-9 genes. In conclusion, zinc showed a positive effect on the maintenance of bone architecture and biomechanical parameters. Indeed, OC upregulation and control of expression of OPG, COL1A, and MMP-9 mRNAs, even in chronic hyperglycemia, support an anabolic

  6. Diffractive elements performance in chromatic confocal microscopy

    International Nuclear Information System (INIS)

    Garzon, J; Duque, D; Alean, A; Toledo, M; Meneses, J; Gharbi, T

    2011-01-01

    The Confocal Laser Scanning Microscopy (CLSM) has been widely used in the semiconductor industry and biomedicine because of its depth discrimination capability. Subsequent to this technique has been developed in recent years Chromatic Confocal Microscopy. This method retains the same principle of confocal and offers the added advantage of removing the axial movement of the moving system. This advantage is usually accomplished with an optical element that generates a longitudinal chromatic aberration and a coding system that relates the axial position of each point of the sample with the wavelength that is focused on each. The present paper shows the performance of compact chromatic confocal microscope when some different diffractive elements are used for generation of longitudinal chromatic aberration. Diffractive elements, according to the process and manufacturing parameters, may have different diffraction efficiency and focus a specific wavelength in a specific focal position. The performance assessment is carried out with various light sources which exhibit an incoherent behaviour and a broad spectral width.

  7. Chromatically unique 6-bridge graph theta(a,a,a,b,b,c

    Directory of Open Access Journals (Sweden)

    N.S.A. Karim

    2016-04-01

    Full Text Available For a graph $G$, let $P(G,\\lambda$ denote the chromatic polynomial of $G$. Two graphs $G$ and $H$ are chromatically equivalent if they share the same chromatic polynomial. A graph $G$ is chromatically unique if for any graph chromatically equivalent to $G$ is isomorphic to $G$. In this paper, the chromatically unique of a new family of 6-bridge graph $\\theta(a,a,a,b,b,c$ where $2\\le a\\le b\\le c$ is investigated.

  8. Chromate dermatitis from a boiler lining.

    Science.gov (United States)

    Rycroft, R J; Calnan, C D

    1977-08-01

    Chromate dermatitis is described in a mechanical fitter working inside boiler combustion chambers. A source of hexavalent chromate is traced to the action of the heat and alkaline fuel ash on trivalent chrome ore in parts of the refractory lining. Removal of the patient from this contact has resulted in almost complete clearing of his dermatitis, without any relapse, during a 9-month follow-up period.

  9. Protective effect of zinc aspartate against acetaminophen induced hepato-renal toxicity in albino rats

    International Nuclear Information System (INIS)

    Mohamed, E.T.; Said, A.I.; El-Sayed, S.A.

    2011-01-01

    Zinc is an essential nutrient that is required in humans and animals for many physiological functions, including antioxidant functions. The evidence to date indicates that zinc is an important element that links antioxidant system and tissue damage. Acetaminophen (AP), a widely used analgesic and antipyretic, produces hepatocyte and renal tubular necrosis in human and animals following overdose. In human, AP is one of the most common causes of acute liver failure as a result of accidental or deliberate overdose. Moreover, the initial event in AP toxicity is a toxic metabolic injury with the release of free radicals and subsequent cellular death by necrosis and apoptosis. This study was designed to evaluate the potential protective role of zinc aspartate in case of acetaminophen induced hepato-renal toxicity in rats. A total number of 32 adult male albino rats were divided into 4 equal groups: group I (control group), group II (zinc aspartate treated group), group III (acetaminophen treated group; by a single oral dose of 750 mg/kg body weight) and group IV acetaminophen plus zinc treated group; (zinc aspartate was intraperitoneally given one hour after acetaminophen administration in a dose of 30 mg/kg body weight). Serum levels of: alanine aminotransferase, aspartate aminotransferase, direct bilirubin, blood urea nitrogen, creatinine, uric acid, xanthine oxidase (XO), glutathione (GSH), malonaldehyde (MDA) and nitric oxide (NO) were assessed in all groups. The results of this study showed that treatment with acetaminophen alone (group III) produced a significant increase in serum levels of the liver enzymes and direct bilirubin. Moreover, in the same group there was a significant increase in the blood urea nitrogen and serum creatinine compared to the control group. In addition, there was a significant increase in XO and MDA and a significant decrease in GSH and NO level. Injection of rats with zinc aspartate after acetaminophen treatment could produce a

  10. Influence of Spatial and Chromatic Noise on Luminance Discrimination.

    Science.gov (United States)

    Miquilini, Leticia; Walker, Natalie A; Odigie, Erika A; Guimarães, Diego Leite; Salomão, Railson Cruz; Lacerda, Eliza Maria Costa Brito; Cortes, Maria Izabel Tentes; de Lima Silveira, Luiz Carlos; Fitzgerald, Malinda E C; Ventura, Dora Fix; Souza, Givago Silva

    2017-12-05

    Pseudoisochromatic figures are designed to base discrimination of a chromatic target from a background solely on the chromatic differences. This is accomplished by the introduction of luminance and spatial noise thereby eliminating these two dimensions as cues. The inverse rationale could also be applied to luminance discrimination, if spatial and chromatic noise are used to mask those cues. In this current study estimate of luminance contrast thresholds were conducted using a novel stimulus, based on the use of chromatic and spatial noise to mask the use of these cues in a luminance discrimination task. This was accomplished by presenting stimuli composed of a mosaic of circles colored randomly. A Landolt-C target differed from the background only by the luminance. The luminance contrast thresholds were estimated for different chromatic noise saturation conditions and compared to luminance contrast thresholds estimated using the same target in a non-mosaic stimulus. Moreover, the influence of the chromatic content in the noise on the luminance contrast threshold was also investigated. Luminance contrast threshold was dependent on the chromaticity noise strength. It was 10-fold higher than thresholds estimated from non-mosaic stimulus, but they were independent of colour space location in which the noise was modulated. The present study introduces a new method to investigate luminance vision intended for both basic science and clinical applications.

  11. In vivo longitudinal chromatic aberration of pseudophakic eyes.

    Science.gov (United States)

    Siedlecki, Damian; Jóźwik, Agnieszka; Zając, Marek; Hill-Bator, Aneta; Turno-Kręcicka, Anna

    2014-02-01

    To present the results of longitudinal chromatic aberration measurements on two groups of pseudophakic eyes in comparison to healthy eyes. The longitudinal chromatic aberration of the eye, defined as chromatic difference of refraction with disabled accommodation, was measured with the use of a visual refractometer with a custom-designed target illuminator consisting of a narrow-band RGB diode (blue λb = 470 ± 15 nm; green λg = 525 ± 18 nm; red λr = 660 ± 10 nm). The measurements were performed on nine eyes implanted with AcrySof IQ SN60WF, 14 eyes implanted with AcrySof SA60AT, and 10 phakic eyes under cycloplegia. The mean values of the longitudinal chromatic aberration between 470 and 660 nm for the control group was 1.12 ± 0.14 D. For SA60AT group, it was 1.45 ± 0.42 D whereas for SN60WF it was 1.17 ± 0.52 D. The statistical test showed significant difference between SA60AT and the control group (p chromatic aberration in vivo can be easily and reliably estimated with an adapted visual refractometer. The two groups of pseudophakic eyes measured in this study showed different values of chromatic aberration. Its magnitude for SA60AT group was significantly larger than for the control group whereas for SN60WF the difference was not significant. The optical material used for intraocular lens design may have significant influence on the magnitude of the chromatic aberration of the pseudophakic eye, and therefore on its optical and visual performance in polychromatic light.

  12. The effect of chromatic and luminance information on reaction times.

    Science.gov (United States)

    O'Donell, Beatriz M; Barraza, Jose F; Colombo, Elisa M

    2010-07-01

    We present a series of experiments exploring the effect of chromaticity on reaction time (RT) for a variety of stimulus conditions, including chromatic and luminance contrast, luminance, and size. The chromaticity of these stimuli was varied along a series of vectors in color space that included the two chromatic-opponent-cone axes, a red-green (L-M) axis and a blue-yellow [S - (L + M)] axis, and intermediate noncardinal orientations, as well as the luminance axis (L + M). For Weber luminance contrasts above 10-20%, RTs tend to the same asymptote, irrespective of chromatic direction. At lower luminance contrast, the addition of chromatic information shortens the RT. RTs are strongly influenced by stimulus size when the chromatic stimulus is modulated along the [S - (L + M)] pathway and by stimulus size and adaptation luminance for the (L-M) pathway. RTs are independent of stimulus size for stimuli larger than 0.5 deg. Data are modeled with a modified version of Pieron's formula with an exponent close to 2, in which the stimulus intensity term is replaced by a factor that considers the relative effects of chromatic and achromatic information, as indexed by the RMS (square-root of the cone contrast) value at isoluminance and the Weber luminance contrast, respectively. The parameters of the model reveal how RT is linked to stimulus size, chromatic channels, and adaptation luminance and how they can be interpreted in terms of two chromatic mechanisms. This equation predicts that, for isoluminance, RTs for a stimulus lying on the S-cone pathway are higher than those for a stimulus lying on the L-M-cone pathway, for a given RMS cone contrast. The equation also predicts an asymptotic trend to the RT for an achromatic stimulus when the luminance contrast is sufficiently large.

  13. Studies on biological reduction of chromate by Streptomyces griseus

    International Nuclear Information System (INIS)

    Poopal, Ashwini C.; Laxman, R. Seeta

    2009-01-01

    Chromium is a toxic heavy metal used in various industries and leads to environmental pollution due to improper handling. The most toxic form of chromium Cr(VI) can be converted to less toxic Cr(III) by reduction. Among the actinomycetes tested for chromate reduction, thirteen strains reduced Cr(VI) to Cr(III), of which one strain of Streptomyces griseus (NCIM 2020) was most efficient showing complete reduction within 24 h. The organism was able to use a number of carbon sources as electron donors. Sulphate, nitrate, chloride and carbonate had no effect on chromate reduction during growth while cations such as Cd, Ni, Co and Cu were inhibitory to varying degrees. Chromate reduction was associated with the bacterial cells and sonication was the best method of cell breakage to release the enzyme. The enzyme was constitutive and did not require presence of chromate during growth for expression of activity. Chromate reduction with cell free extract (CFE) was observed without added NADH. However, addition of NAD(P)H resulted in 2-3-fold increase in activity. Chromate reductase showed optimum activity at 28 deg. C and pH 7.

  14. Electroplating U-0.75 Ti, 105-mm, XM774 penetrators with nickel and zinc

    International Nuclear Information System (INIS)

    Dini, J.W.; Johnson, H.R.

    1976-06-01

    Procedures were developed and utilized whereby 105-mm U-Ti penetrators were plated with 1.0 mil of nickel and 0.2 mil of zinc and then chromated. Twenty-three full-size penetrators were coated to demonstrate the feasibility of the system and to provide parts for ballistic tests. Dimensional inspection of the parts before and after etching and plating revealed the coating process to be viable and repeatable

  15. Simultaneous chromatic and luminance human electroretinogram responses.

    Science.gov (United States)

    Parry, Neil R A; Murray, Ian J; Panorgias, Athanasios; McKeefry, Declan J; Lee, Barry B; Kremers, Jan

    2012-07-01

    The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats' ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing.

  16. Investigation of the chromate conversion coating on Alclad 2024 aluminium alloy: effect of the pH of the chromate bath

    NARCIS (Netherlands)

    Campestrini, P.; Westing, E.P.M. van; Hovestad, A.; Wit, J.H.W. de

    2002-01-01

    The parameters of the chromate bath, like temperature, pH, and fluoride content, strongly affect the morphology and chemical composition of the chromate conversion coating and as a consequence have a large influence on its corrosion performance. In this paper, electrochemical impedance spectroscopy

  17. Zinc supplementation suppresses the progression of bile duct ligation-induced liver fibrosis in mice.

    Science.gov (United States)

    Shi, Fang; Sheng, Qin; Xu, Xinhua; Huang, Wenli; Kang, Y James

    2015-09-01

    Metallothionein (MT) gene therapy leads to resolution of liver fibrosis in mouse model, in which the activation of collagenases is involved in the regression of liver fibrosis. MT plays a critical role in zinc sequestration in the liver suggesting its therapeutic effect would be mediated by zinc. The present study was undertaken to test the hypothesis that zinc supplementation suppresses liver fibrosis. Male Kunming mice subjected to bile duct ligation (BDL) resulted in liver fibrosis as assessed by increased α-smooth muscle actin (α-SMA) and collagen I production/deposition in the liver. Zinc supplementation was introduced 4 weeks after BDL surgery via intragastric administration once daily for 2 weeks resulting in a significant reduction in the collagen deposition in the liver and an increase in the survival rate. Furthermore, zinc suppressed gene expression of α-SMA and collagen I and enhanced the capacity of collagen degradation, as determined by the increased activity of total collagenases and elevated mRNA and protein levels of MMP13. Therefore, the results demonstrate that zinc supplementation suppresses BDL-induced liver fibrosis through both inhibiting collagen production and enhancing collagen degradation. © 2014 by the Society for Experimental Biology and Medicine.

  18. Detection of chromatic and luminance distortions in natural scenes.

    Science.gov (United States)

    Jennings, Ben J; Wang, Karen; Menzies, Samantha; Kingdom, Frederick A A

    2015-09-01

    A number of studies have measured visual thresholds for detecting spatial distortions applied to images of natural scenes. In one study, Bex [J. Vis.10(2), 1 (2010)10.1167/10.2.231534-7362] measured sensitivity to sinusoidal spatial modulations of image scale. Here, we measure sensitivity to sinusoidal scale distortions applied to the chromatic, luminance, or both layers of natural scene images. We first established that sensitivity does not depend on whether the undistorted comparison image was of the same or of a different scene. Next, we found that, when the luminance but not chromatic layer was distorted, performance was the same regardless of whether the chromatic layer was present, absent, or phase-scrambled; in other words, the chromatic layer, in whatever form, did not affect sensitivity to the luminance layer distortion. However, when the chromatic layer was distorted, sensitivity was higher when the luminance layer was intact compared to when absent or phase-scrambled. These detection threshold results complement the appearance of periodic distortions of the image scale: when the luminance layer is distorted visibly, the scene appears distorted, but when the chromatic layer is distorted visibly, there is little apparent scene distortion. We conclude that (a) observers have a built-in sense of how a normal image of a natural scene should appear, and (b) the detection of distortion in, as well as the apparent distortion of, natural scene images is mediated predominantly by the luminance layer and not chromatic layer.

  19. Luminance cues constrain chromatic blur discrimination in natural scene stimuli.

    Science.gov (United States)

    Sharman, Rebecca J; McGraw, Paul V; Peirce, Jonathan W

    2013-03-22

    Introducing blur into the color components of a natural scene has very little effect on its percept, whereas blur introduced into the luminance component is very noticeable. Here we quantify the dominance of luminance information in blur detection and examine a number of potential causes. We show that the interaction between chromatic and luminance information is not explained by reduced acuity or spatial resolution limitations for chromatic cues, the effective contrast of the luminance cue, or chromatic and achromatic statistical regularities in the images. Regardless of the quality of chromatic information, the visual system gives primacy to luminance signals when determining edge location. In natural viewing, luminance information appears to be specialized for detecting object boundaries while chromatic information may be used to determine surface properties.

  20. Chromatic graph theory

    CERN Document Server

    Chartrand, Gary; Rosen, Kenneth H

    2008-01-01

    Beginning with the origin of the four color problem in 1852, the field of graph colorings has developed into one of the most popular areas of graph theory. Introducing graph theory with a coloring theme, Chromatic Graph Theory explores connections between major topics in graph theory and graph colorings as well as emerging topics. This self-contained book first presents various fundamentals of graph theory that lie outside of graph colorings, including basic terminology and results, trees and connectivity, Eulerian and Hamiltonian graphs, matchings and factorizations, and graph embeddings. The remainder of the text deals exclusively with graph colorings. It covers vertex colorings and bounds for the chromatic number, vertex colorings of graphs embedded on surfaces, and a variety of restricted vertex colorings. The authors also describe edge colorings, monochromatic and rainbow edge colorings, complete vertex colorings, several distinguishing vertex and edge colorings, and many distance-related vertex coloring...

  1. The influence of chromatic context on binocular color rivalry: Perception and neural representation

    Science.gov (United States)

    Hong, Sang Wook; Shevell, Steven K.

    2008-01-01

    The predominance of rivalrous targets is affected by surrounding context when stimuli rival in orientation, motion or color. This study investigated the influence of chromatic context on binocular color rivalry. The predominance of rivalrous chromatic targets was measured in various surrounding contexts. The first experiment showed that a chromatic surround's influence was stronger when the surround was uniform or a grating with luminance contrast (chromatic/black grating) compared to an equiluminant grating (chromatic/white). The second experiment revealed virtually no effect of the orientation of the surrounding chromatic context, using chromatically rivalrous vertical gratings. These results are consistent with a chromatic representation of the context by a non-oriented, chromatically selective and spatially antagonistic receptive field. Neither a double-opponent receptive field nor a receptive field without spatial antagonism accounts for the influence of context on binocular color rivalry. PMID:18331750

  2. Game chromatic number of lexicographic product graphs

    Directory of Open Access Journals (Sweden)

    R. Alagammai

    2015-11-01

    Full Text Available In this paper, we determine the exact values of the game chromatic number of lexicographic product of path P2 with path Pn, star K1,n and wheel Wn. Also we give an upper bound for the game chromatic number of lexicographic product of any two simple graphs G and H.

  3. Infinitely connected subgraphs in graphs of uncountable chromatic number

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2016-01-01

    Erdős and Hajnal conjectured in 1966 that every graph of uncountable chromatic number contains a subgraph of infinite connectivity. We prove that every graph of uncountable chromatic number has a subgraph which has uncountable chromatic number and infinite edge-connectivity. We also prove that......, if each orientation of a graph G has a vertex of infinite outdegree, then G contains an uncountable subgraph of infinite edge-connectivity....

  4. Effects of nickel, chromate, and arsenite on histone 3 lysine methylation

    International Nuclear Information System (INIS)

    Zhou Xue; Li Qin; Arita, Adriana; Sun Hong; Costa, Max

    2009-01-01

    Occupational exposure to nickel (Ni), chromium (Cr), and arsenic (As) containing compounds has been associated with lung cancer and other adverse health effects. Their carcinogenic properties may be attributable in part, to activation and/or repression of gene expression induced by changes in the DNA methylation status and histone tail post-translational modifications. Here we show that individual treatment with nickel, chromate, and arsenite all affect the gene activating mark H3K4 methylation. We found that nickel (1 mM), chromate (10 μM), and arsenite (1 μM) significantly increase tri-methyl H3K4 after 24 h exposure in human lung carcinoma A549 cells. Seven days of exposure to lower levels of nickel (50 and 100 μM), chromate (0.5 and 1 μM) or arsenite (0.1, 0.5 and 1 μM) also increased tri-methylated H3K4 in A549 cells. This mark still remained elevated and inherited through cell division 7 days following removal of 1 μM arsenite. We also demonstrate by dual staining immunofluorescence microscopy that both H3K4 tri-methyl and H3K9 di-methyl marks increase globally after 24 h exposure to each metal treatment in A549 cells. However, the tri-methyl H3K4 and di-methyl H3K9 marks localize in different regions in the nucleus of the cell. Thus, our study provides further evidence that a mechanism(s) of carcinogenicity of nickel, chromate, and arsenite metal compounds may involve alterations of various histone tail modifications that may in turn affect the expression of genes that may cause transformation

  5. Chromate ion-exchange study for cooling water

    International Nuclear Information System (INIS)

    Sengupta, A.K.

    1985-01-01

    In spite of high chromate selectivity, the ion-exchange process for Cr(IV) recovery from cooling tower blowdown is yet to be commercially popular. Possible degradation of the ion-exchange resin by the oxidative action of Cr(IV) during ion exchange has been considered as the prime obstacle. Resins have been manufactured with fairly acceptable properties to withstand both physical attrition and chemical oxidation. Demonstrated during the course of this research is early, gradual Cr(VI) breakthrough during fixed-bed column runs at acidic pH in the presence of competing sulfate and chloride anions. The advantage of high chromate selectivity is essentially lost due to the early Cr(VI) breakthrough because the column runs are always terminated after a pre-determined level of Cr(VI) has appeared in the treated water. Experimental results provide sufficient evidence that this is not due to poor column kinetics or electrolyte penetration. The chromate ion-exchange mechanism has been investigated in order to explain the foregoing anomalies for the chromate-exchange process. The knowledge of chromate ion-exchange mechanism has been used to overcome the shortcoming of gradual Cr(VI) breakthrough. This study shows that: (a) a continuous counter-current ion-exchange system theoretically offers much higher Cr(VI) removal capacity compared to conventional single-unit fixed-bed system for any pre-determined level of Cr(VI) breakthrough; (b) by modifying the resin composition, the gradual Cr(VI) breakthrough can be greatly eliminated

  6. Local chromatic correction scheme for LER of PEP-II

    International Nuclear Information System (INIS)

    Forest, E.; Robin, D.; Zholents, A.; Donald, M.; Helm, R.; Irwin, J.; Sullivan, M.K.

    1993-01-01

    The correction of the chromaticity of low-beta insertions in storage rings is usually made with sextupole lenses in the ring arcs. When decreasing the beta functions at the interaction point (IP), this technique becomes fairly ineffective, since it fails to properly correct the higher-order chromatic aberrations. Here we consider the approach for ampersand PEP-II B Factory low energy ring (LER) where the chromatic effects of the quadrupole lenses generating low beta functions at the IP are corrected locally with two families of sextupoles, one family for each plane. For the IP straight section the lattice is designed in such a way that the chromatic aberrations are made small and sextupole-like aberrations are eliminated. The results of dimensional tracking simulations are presented

  7. Chromatic aberrations of two-electrode transaxial mirrors

    International Nuclear Information System (INIS)

    Bejzina, L.G.; Karetskaya, S.P.

    1991-01-01

    Second order chromatic aberrations of electrostatic two-electrode transaxial mirrors in case the beam axial trajectory of charged particles is curvilinear are considered. Interrelations between coefficients of linear and angular chromatic aberrations are determined. Values of these coefficients for concave and convex transaxial mirrors with plane electrodes in dependence on potential ratio on electrodes by different onnular clearance radii are presented

  8. A linear chromatic mechanism drives the pupillary response.

    Science.gov (United States)

    Tsujimura, S.; Wolffsohn, J. S.; Gilmartin, B.

    2001-01-01

    Previous studies have shown that a chromatic mechanism can drive pupil responses. The aim of this research was to clarify whether a linear or nonlinear chromatic mechanism drives pupillary responses by using test stimuli of various colours that are defined in cone contrast space. The pupil and accommodation responses evoked by these test stimuli were continuously and simultaneously objectively measured by photorefraction. The results with isochromatic and isoluminant stimuli showed that the accommodative level remained approximately constant (< 0.25 D change in mean level) even when the concurrent pupillary response was large (ca. 0.30 mm). The pupillary response to an isoluminant grating was sustained, delayed (by ca. 60 ms) and larger in amplitude than that for a isochromatic uniform stimulus, which supports previous work suggesting that the chromatic mechanism contributes to the pupillary response. In a second experiment, selected chromatic test gratings were used and isoresponse contours in cone contrast space were obtained. The results showed that the isoresponse contour in cone contrast space is well described (r(2) = 0.99) by a straight line with a positive slope. The results indicate that a /L - M/ linear chromatic mechanism, whereby a signal from the long wavelength cone is subtracted from that of the middle wavelength cone and vice versa, drives pupillary responses. PMID:11674867

  9. Scaling Laws for Dynamic Aperture due to Chromatic Sextupoles

    CERN Document Server

    Scandale, Walter

    1997-01-01

    Scaling laws for the dynamic aperture due to chromatic sextupoles are investigated. The problem is addressed in a simplified lattice model containing 4 N identical cells and one linear betatron phase shifter to break the overall cell-lattice symmetry. Two families of chromatic sextupoles are used to compensate the natural chromaticity. Analytical formulae for the dynamic apertur as a function of the number of cells and of the cell length are found and confirmed through computer tracking.

  10. Chromatic Dimensions Earthy, Watery, Airy, and Fiery.

    Science.gov (United States)

    Albertazzi, Liliana; Koenderink, Jan J; van Doorn, Andrea

    2015-01-01

    In our study, for a small number of antonyms, we investigate whether they are cross-modally or ideaesthetically related to the space of colors. We analyze the affinities of seven antonyms (cold-hot, dull-radiant, dead-vivid, soft-hard, transparent-chalky, dry-wet, and acid-treacly) and their intermediate connotations (cool-warm, matt-shiny, numb-lively, mellow-firm, semi-transparent-opaque, semi-dry-moist, and sour-sweet) as a function of color. We find that some antonyms relate to chromatic dimensions, others to achromatic ones. The cold-hot antonym proves to be the most salient dimension. The dry-wet dimension coincides with the cold-hot dimension, with dry corresponding to hot and wet to cold. The acid-treacly dimension proves to be transversal to the cold-hot dimension; hence, the pairs mutually span the chromatic domain. The cold-hot and acid-treacly antonyms perhaps recall Hering's opponent color system. The dull-radiant, transparent-chalky, and dead-vivid pairs depend little upon chromaticity. Of all seven antonyms, only the soft-hard one turns out to be independent of the chromatic structure. © The Author(s) 2015.

  11. Delays in using chromatic and luminance information to correct rapid reaches.

    Science.gov (United States)

    Kane, Adam; Wade, Alex; Ma-Wyatt, Anna

    2011-09-07

    People can use feedback to make online corrections to movements but only if there is sufficient time to integrate the new information and make the correction. A key variable in this process is therefore the speed at which the new information about the target location is coded. Conduction velocities for chromatic signals are lower than for achromatic signals so it may take longer to correct reaches to chromatic stimuli. In addition to this delay, the sensorimotor system may prefer achromatic information over the chromatic information as delayed information may be less valuable when movements are made under time pressure. A down-weighting of chromatic information may result in additional latencies for chromatically directed reaches. In our study, participants made online corrections to reaches to achromatic, (L-M)-cone, and S-cone stimuli. Our chromatic stimuli were carefully adjusted to minimize stimulation of achromatic pathways, and we equated stimuli both in terms of detection thresholds and also by their estimated neural responses. Similar stimuli were used throughout the subjective adjustments and final reaching experiment. Using this paradigm, we found that responses to achromatic stimuli were only slightly faster than responses to (L-M)-cone and S-cone stimuli. We conclude that the sensorimotor system treats chromatic and achromatic information similarly and that the delayed chromatic responses primarily reflect early conduction delays.

  12. Zinc prevents sickness behavior induced by lipopolysaccharides after a stress challenge in rats.

    Directory of Open Access Journals (Sweden)

    Thiago B Kirsten

    Full Text Available Sickness behavior is considered part of the specific beneficial adaptive behavioral and neuroimmune changes that occur in individuals in response to infectious/inflammatory processes. However, in dangerous and stressful situations, sickness behavior should be momentarily abrogated to prioritize survival behaviors, such as fight or flight. Taking this assumption into account, we experimentally induced sickness behavior in rats using lipopolysaccharides (LPS, an endotoxin that mimics infection by gram-negative bacteria, and then exposed these rats to a restraint stress challenge. Zinc has been shown to play a regulatory role in the immune and nervous systems. Therefore, the objective of this study was to examine the effects of zinc treatment on the sickness response of stress-challenged rats. We evaluated 22-kHz ultrasonic vocalizations, open-field behavior, tumor necrosis factor α (TNF-α, corticosterone, and brain-derived neurotrophic factor (BDNF plasma levels. LPS administration induced sickness behavior in rats compared to controls, i.e., decreases in the distance traveled, average velocity, rearing frequency, self-grooming, and number of vocalizations, as well as an increase in the plasma levels of TNF-α, compared with controls after a stressor challenge. LPS also decreased BDNF expression but did not influence anxiety parameters. Zinc treatment was able to prevent sickness behavior in LPS-exposed rats after the stress challenge, restoring exploratory/motor behaviors, communication, and TNF-α levels similar to those of the control group. Thus, zinc treatment appears to be beneficial for sick animals when they are facing risky/stressful situations.

  13. Zinc deficiency-induced iron accumulation, a consequence of alterations in iron regulatory protein-binding activity, iron transporters, and iron storage proteins.

    Science.gov (United States)

    Niles, Brad J; Clegg, Michael S; Hanna, Lynn A; Chou, Susan S; Momma, Tony Y; Hong, Heeok; Keen, Carl L

    2008-02-22

    One consequence of zinc deficiency is an elevation in cell and tissue iron concentrations. To examine the mechanism(s) underlying this phenomenon, Swiss 3T3 cells were cultured in zinc-deficient (D, 0.5 microM zinc), zinc-supplemented (S, 50 microM zinc), or control (C, 4 microM zinc) media. After 24 h of culture, cells in the D group were characterized by a 50% decrease in intracellular zinc and a 35% increase in intracellular iron relative to cells in the S and C groups. The increase in cellular iron was associated with increased transferrin receptor 1 protein and mRNA levels and increased ferritin light chain expression. The divalent metal transporter 1(+)iron-responsive element isoform mRNA was decreased during zinc deficiency-induced iron accumulation. Examination of zinc-deficient cells revealed increased binding of iron regulatory protein 2 (IRP2) and decreased binding of IRP1 to a consensus iron-responsive element. The increased IRP2-binding activity in zinc-deficient cells coincided with an increased level of IRP2 protein. The accumulation of IRP2 protein was independent of zinc deficiency-induced intracellular nitric oxide production but was attenuated by the addition of the antioxidant N-acetylcysteine or ascorbate to the D medium. These data support the concept that zinc deficiency can result in alterations in iron transporter, storage, and regulatory proteins, which facilitate iron accumulation.

  14. Study of chromatic adaptation via neutral white matches on different viewing media.

    Science.gov (United States)

    Zhai, Qiyan; Luo, Ming R

    2018-03-19

    Two experiments were carried out to study the neutral white and the chromatic adaptation in human vision and color science. After matching neutral whites under different illuminants using both surface and self-luminous colors, the result were used to verify the previous study about the chromatic adaptation. Not all the white illuminants were found neutral even the adaptation time is long. The baseline illuminant of the two-step chromatic adaptation transform was found as the illuminant with the same chromaticity of the neutral white under it and depended on viewing medium in the present study. The results were also used as corresponding colors to derive models of the effective degree of chromatic adaptation, which were found highly associated with the chromaticity of the adapting illuminant.

  15. Chromatic-achromatic perimetry in four clinic cases: Glaucoma and diabetes.

    Science.gov (United States)

    Cabezos, Inmaculada; Luque, Maria Jos; de Fez, Dolores; Moncho, Vicenta; Camps, Vicente

    2015-02-01

    Some diseases that affect the visual system may show loss of chromatic-achromatic sensitivity before obvious physical signs appear in the usual examination of the eye's posterior segment. A perimetric study has been conducted with four typical patients with glaucoma and diabetes, at different stages of the disease. In addition to the standard white-on-white (standard automated perimetry [SAP]), a test battery has been used to study patient's contrast sensitivity, using stimuli with different chromatic, spatial, and temporal content (multichannel perimetry). The choice of stimuli tries to maximize the response of different visual mechanisms: Achromatic (parvocellular and magnocellular origin); chromatic red-green (parvocellular origin); and chromatic blue-yellow (koniocellular origin). The results seem to indicate losses in the achromatic-parvocellular perimetry and both chromatic perimetry tests, undetected by conventional SAP. Our results illustrate that our patients without visible retinal alterations show signs of suspicion in multichannel perimetry.

  16. Mapping chromatic pathways in the Drosophila visual system.

    Science.gov (United States)

    Lin, Tzu-Yang; Luo, Jiangnan; Shinomiya, Kazunori; Ting, Chun-Yuan; Lu, Zhiyuan; Meinertzhagen, Ian A; Lee, Chi-Hon

    2016-02-01

    In Drosophila, color vision and wavelength-selective behaviors are mediated by the compound eye's narrow-spectrum photoreceptors R7 and R8 and their downstream medulla projection (Tm) neurons Tm5a, Tm5b, Tm5c, and Tm20 in the second optic neuropil or medulla. These chromatic Tm neurons project axons to a deeper optic neuropil, the lobula, which in insects has been implicated in processing and relaying color information to the central brain. The synaptic targets of the chromatic Tm neurons in the lobula are not known, however. Using a modified GFP reconstitution across synaptic partners (GRASP) method to probe connections between the chromatic Tm neurons and 28 known and novel types of lobula neurons, we identify anatomically the visual projection neurons LT11 and LC14 and the lobula intrinsic neurons Li3 and Li4 as synaptic targets of the chromatic Tm neurons. Single-cell GRASP analyses reveal that Li4 receives synaptic contacts from over 90% of all four types of chromatic Tm neurons, whereas LT11 is postsynaptic to the chromatic Tm neurons, with only modest selectivity and at a lower frequency and density. To visualize synaptic contacts at the ultrastructural level, we develop and apply a "two-tag" double-labeling method to label LT11's dendrites and the mitochondria in Tm5c's presynaptic terminals. Serial electron microscopic reconstruction confirms that LT11 receives direct contacts from Tm5c. This method would be generally applicable to map the connections of large complex neurons in Drosophila and other animals. © 2015 Wiley Periodicals, Inc.

  17. Zinc rescues obesity-induced cardiac hypertrophy via stimulating metallothionein to suppress oxidative stress-activated BCL10/CARD9/p38 MAPK pathway.

    Science.gov (United States)

    Wang, Shudong; Gu, Junlian; Xu, Zheng; Zhang, Zhiguo; Bai, Tao; Xu, Jianxiang; Cai, Jun; Barnes, Gregory; Liu, Qiu-Ju; Freedman, Jonathan H; Wang, Yonggang; Liu, Quan; Zheng, Yang; Cai, Lu

    2017-06-01

    Obesity often leads to obesity-related cardiac hypertrophy (ORCH), which is suppressed by zinc-induced inactivation of p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated the mechanisms by which zinc inactivates p38 MAPK to prevent ORCH. Mice (4-week old) were fed either high fat diet (HFD, 60% kcal fat) or normal diet (ND, 10% kcal fat) containing variable amounts of zinc (deficiency, normal and supplement) for 3 and 6 months. P38 MAPK siRNA and the p38 MAPK inhibitor SB203580 were used to suppress p38 MAPK activity in vitro and in vivo, respectively. HFD activated p38 MAPK and increased expression of B-cell lymphoma/CLL 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These responses were enhanced by zinc deficiency and attenuated by zinc supplement. Administration of SB203580 to HFD mice or specific siRNA in palmitate-treated cardiomyocytes eliminated the HFD and zinc deficiency activation of p38 MAPK, but did not significantly impact the expression of BCL10 and CARD9. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide (ANP) expression. In contrast, inhibition of p38 MAPK prevented ANP expression, but did not affect BCL10 expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signalling. Zinc supplement ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  18. Multi-Chromatic Ultrashort Pulse Filamentation and Bulk Modification in Dielectrics

    Science.gov (United States)

    2016-05-05

    AFRL-AFOSR-VA-TR-2016-0194 Multi- Chromatic Ultrashort Pulse Filamentation and Bulk Modification in Dielectrics Jeremy Gulley KENNESAW STATE...Jan 2016 4. TITLE AND SUBTITLE Multi- chromatic Ultrashort Pulse Filamentation and Bulk Modification in Dielectrics 5a. CONTRACT NUMBER 5b. GRANT...in, and modification of, dielectric solids by multi- chromatic ultrashort laser pulses. It was a theoretical effort to develop models of multi

  19. The effect of chromate on IGSCC in boiling water reactors - a SSRT study

    International Nuclear Information System (INIS)

    Ullberg, M.

    1992-01-01

    The effect of chromate on IGSCC in Type 304 stainless steel was investigated using the Slow Strain Rate Technique (SSRT). It was found that low concentrations of chromate raises the corrosion potential of SS and causes IGSCC. The effect of chromate was compared to that of the main oxidant in BWRs, hydrogen peroxide. Chromate was found to have less tendency than hydrogen peroxide, at one and the same corrosion potential, to cause IGSCC in SSRT tests. This is interpreted as due to chromate being a better anodic inhibitor than hydrogen peroxide. As a consequence, initiation of IGSCC is slower in the presence of chromate. At least during normal water chemistry, chromate is a secondary oxidant in all of the BWR reactor coolant system. The ECP is then determined by the primary oxidant, hydrogen peroxide. Therefore, the chromate transients which may occur in BWR reactor coolant systems should have no significant effect on IGSCC

  20. Chromatic blur perception in the presence of luminance contrast.

    Science.gov (United States)

    Jennings, Ben J; Kingdom, Frederick A A

    2017-06-01

    Hel-Or showed that blurring the chromatic but not the luminance layer of an image of a natural scene failed to elicit any impression of blur. Subsequent studies have suggested that this effect is due either to chromatic blur being masked by spatially contiguous luminance edges in the scene (Journal of Vision 13 (2013) 14), or to a relatively compressed transducer function for chromatic blur (Journal of Vision 15 (2015) 6). To test between the two explanations we conducted experiments using as stimuli both images of natural scenes as well as simple edges. First, we found that in color-and-luminance images of natural scenes more chromatic blur was needed to perceptually match a given level of blur in an isoluminant, i.e. colour-only scene. However, when the luminance layer in the scene was rotated relative to the chromatic layer, thus removing the colour-luminance edge correlations, the matched blur levels were near equal. Both results are consistent with Sharman et al.'s explanation. Second, when observers matched the blurs of luminance-only with isoluminant scenes, the matched blurs were equal, against Kingdom et al.'s prediction. Third, we measured the perceived blur in a square-wave as a function of (i) contrast (ii) number of luminance edges and (iii) the relative spatial phase between the colour and luminance edges. We found that the perceived chromatic blur was dependent on both relative phase and the number of luminance edges, or dependent on the luminance contrast if only a single edge is present. We conclude that this Hel-Or effect is largely due to masking of chromatic blur by spatially contiguous luminance edges. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Chromatic-achromatic perimetry in four clinic cases: Glaucoma and diabetes

    Directory of Open Access Journals (Sweden)

    Inmaculada Cabezos

    2015-01-01

    Full Text Available Background: Some diseases that affect the visual system may show loss of chromatic-achromatic sensitivity before obvious physical signs appear in the usual examination of the eye′s posterior segment. A perimetric study has been conducted with four typical patients with glaucoma and diabetes, at different stages of the disease. Materials and Methods: In addition to the standard white-on-white (standard automated perimetry [SAP], a test battery has been used to study patient′s contrast sensitivity, using stimuli with different chromatic, spatial, and temporal content (multichannel perimetry. The choice of stimuli tries to maximize the response of different visual mechanisms: Achromatic (parvocellular and magnocellular origin; chromatic red-green (parvocellular origin; and chromatic blue-yellow (koniocellular origin. Results: The results seem to indicate losses in the achromatic-parvocellular perimetry and both chromatic perimetry tests, undetected by conventional SAP. Conclusions: Our results illustrate that our patients without visible retinal alterations show signs of suspicion in multichannel perimetry.

  2. Effect of pressure on the radiation annealing of recoil atoms in chromates

    International Nuclear Information System (INIS)

    Stamouli, M.I.

    1986-01-01

    The effect of pressure on the annealing of recoil atoms by gamma radiation in neutron irradiated potassium chromate, ammonium chromate and ammonium dichromate was studied. In potassium chromate the pressure applied before the gamma-irradiation was found to retard the radiation annealing process. In ammonium chromate and ammonium dichromate the radiation annealing was found to be enhanced in the compressed samples in comparison to the noncompressed ones. (author)

  3. The chromatic polynomial and list colorings

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2009-01-01

    We prove that, if a graph has a list of k available colors at every vertex, then the number of list-colorings is at least the chromatic polynomial evaluated at k when k is sufficiently large compared to the number of vertices of the graph.......We prove that, if a graph has a list of k available colors at every vertex, then the number of list-colorings is at least the chromatic polynomial evaluated at k when k is sufficiently large compared to the number of vertices of the graph....

  4. Formulation of nonlinear chromaticity in circular accelerators by canonical perturbation method

    International Nuclear Information System (INIS)

    Takao, Masaru

    2005-01-01

    The formulation of nonlinear chromaticity in circular accelerators based on the canonical perturbation method is presented. Since the canonical perturbation method directly relates the tune shift to the perturbation Hamiltonian, it greatly simplifies the calculation of the nonlinear chromaticity. The obtained integral representation for nonlinear chromaticity can be systematically extended to higher orders

  5. Preliminary Studies Of A Phase Modulation Technique For Measuring Chromaticity

    International Nuclear Information System (INIS)

    Tan, C.-Y.

    2006-01-01

    The classical method for measuring chromaticity is to slowly modulate the RF frequency and then measure the betatron tune excursion. The technique that is discussed in this paper instead modulates the phase of the RF and then the chromaticity is obtained by phase demodulating the betatron tune. This technique requires knowledge of the betatron frequency in real time in order for the phase to be demodulated. Fortunately, the Tevatron has a tune tracker based on the phase locked loop principle which fits this requirement. A preliminary study with this technique has showed that it is a promising method for doing continuous chromaticity measurement and raises the possibility of doing successful chromaticity feedback with it

  6. Semantics of color in chromatism

    Science.gov (United States)

    Serov, Nikolai V.

    2002-06-01

    The aim of this investigation is to describe the semantics of color in chromatism (from the ancient Greek triune notion of >: (1) color as ideal (Id- plan), psychic; (2) tint as physical, verbal; material (M- plan), physiological, syntonic (S-plan), and (3) emotion as their informative-energetic correlation). Being a new field of science, chromatism links humanitarian and natural subjects by means of interdiscipline investigation of a real (f-m) man living in a real (color) surrounding environment. According to the definition for >, color may be considered to be the most universal notion, permitting to assume the unity of both a man and an environment. Due to this assumption, we may give models of human intellect.

  7. Zinc supplementation alleviates the progression of diabetic nephropathy by inhibiting the overexpression of oxidative-stress-mediated molecular markers in streptozotocin-induced experimental rats.

    Science.gov (United States)

    Barman, Susmita; Pradeep, Seetur R; Srinivasan, Krishnapura

    2018-04-01

    Zinc deficiency during diabetes projects a role for zinc nutrition in the management of diabetic nephropathy. The current study explored whether zinc supplementation protects against diabetic nephropathy through modulation of kidney oxidative stress and stress-induced expression related to the inflammatory process in streptozotocin-induced diabetic rats. Groups of hyperglycemic rats were exposed to dietary interventions for 6 weeks with zinc supplementation (5 times and 10 times the normal level). Supplemental-zinc-fed diabetic groups showed a significant reversal of increased kidney weight and creatinine clearance. There was a significant reduction in hyperlipidemic condition along with improved PUFA:SFA ratio in the renal tissue. Expression of the lipid oxidative marker and expression of inflammatory markers, cytokines, fibrosis factors and apoptotic regulatory proteins observed in diabetic kidney were beneficially modulated by zinc supplementation, the ameliorative effect being concomitant with elevated antiapoptosis. There was a significant reduction in advanced glycation, expression of the receptor of the glycated products and oxidative stress markers. Zinc supplementation countered the higher activity and expression of polyol pathway enzymes in the kidney. Overexpression of the glucose transporters, as an adaptation to the increased need for glucose transport in diabetic condition, was minimized by zinc treatment. The pathological abnormalities in the renal architecture of diabetic animals were corrected by zinc intervention. Thus, dietary zinc supplementation has a significant beneficial effect in the control of diabetic nephropathy. This was exerted through a protective influence on oxidative-stress-induced cytokines, inflammatory proliferation and consequent renal injury. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Chromatic correction for the final transport system

    International Nuclear Information System (INIS)

    Brown, K.L.; Peterson, J.M.

    1980-01-01

    The final transport and focusing of the heavy-ion beam onto the fusion pellet in vacuum is complicated by several non-linear effects - namely, chromatic (momentum dependent) effects, geometric aberrations, and space-charge forces. This paper gives an example of how the chromatic effects can be nullified, at least to second order. Whether third- or higher-order terms are important is not yet clear. Space-charge effects are important but are not considered here

  9. Determination of chromate ion in drilling mud filtrates

    International Nuclear Information System (INIS)

    Whitfill, D.

    1980-01-01

    A method of determining the amount of chromate ion in an aqueous drilling mud filtrate containing organic color bodies such as lignosulfate wherein the method comprises: (A) treating the aqueous filtrate with an effective amount of hydrogen peroxide to destroy said color bodies, and (B) measuring the amount of chromate ion in the filtrate by means of a spectrophotometer

  10. Chromate-reducing activity of Hansenula polymorpha recombinant cells over-producing flavocytochrome b₂.

    Science.gov (United States)

    Smutok, Oleh; Broda, Daniel; Smutok, Halyna; Dmytruk, Kostyantyn; Gonchar, Mykhailo

    2011-04-01

    In spite of the great interest to studies of the biological roles of chromium, as well as the toxic influence of Cr(VI)-species on living organisms, the molecular mechanisms of chromate bioremediation remain vague. A reductive pathway resulting in formation of less toxic Cr(III)-species is suggested to be the most important among possible mechanisms for chromate biodetoxification. The yeast l-lactate:cytochrome c-oxidoreductase (flavocytochrome b(2), FC b(2)) has absolute specificity for l-lactate, yet is non-selective with respect to its electron acceptor. These properties allow us to consider the enzyme as a potential candidate for chromate reduction by living cells in the presence of l-lactate. A recombinant strain of thermotolerant, methylotrophic yeast Hansenula polymorpha with sixfold increased FC b(2) enzyme activity (up to 3μmolmin(-1)mg(-1) protein in cell-free extract) compared to the parental strain was used for approval our suggestion. The recombinant cells, stored in dried state, as well as living yeast cells were tested for chromate-reducing activity in vitro in the presence of l-lactate (as an electron donor for chromate reduction) and different low molecular weight, redox-active mediators facilitating electron transfer from the reduced form of the enzyme to chromate (as a final electron acceptor): dichlorophenolindophenol (DCPIP), Methylene blue, Meldola blue, and Nile blue. It was shown that the highest chromate-reducing activity of the cells was achieved in the presence of DCPIP. The ability of chromate to catch electrons from the reduced flavocytochrome b(2) was confirmed using purified enzyme immobilized on the surface of a platinum electrode. The increasing concentration of Cr(VI) resulted in a decrease of enzyme-mediated current generated on the electrode during l-lactate oxidation. The shift and drop in amplitude of the peak in the cyclic voltammogram are indicative of Cr(VI)-dependent competition between reaction of chromate with reduced FC

  11. Implication of extracellular zinc exclusion by recombinant human calprotectin (MRP8 and MRP14) from target cells in its apoptosis-inducing activity.

    Science.gov (United States)

    Yui, Satoru; Nakatani, Yuichi; Hunter, Michael J; Chazin, Walter J; Yamazaki, Masatoshi

    2002-06-01

    Calprotectin is a calcium-binding and zinc-binding protein complex that is abundant in the cytosol of neutrophils. This factor is composed of 8 and 14 kDa subunits, which have also been termed migration inhibitory factor-related proteins MRP8 and MRP14. We previously reported that rat calprotectin purified from inflammatory neutrophils induces apoptosis of various tumor cells or normal fibroblasts in a zinc-reversible manner. The present study was undertaken to elucidate which subunit is responsible for the apoptosis-inducing activity, and to explore the mechanism of zinc-reversible apoptosis induction. The apoptosis-inducing activity of recombinant human MRP8 (rhMRP8) and recombinant human MRP14 (rhMRP14) was examined against EL-4 lymphoma cells in vitro. To determine whether zinc deprivation by calprotectin was essential for the cytotoxicity, the activity of calprotectin was tested under conditions where physical contact between the factor and the cells was precluded by a low molecular weight cut-off dialysis membrane. The cytotoxicity of rhMRP14 against EL-4 cells was first detected at 10 microM in a standard medium, whereas rhMRP8 caused only marginal cytotoxicity at 40 microM. A mixture of both proteins showed higher specific activity (onset of cytotoxicity at 5 microM). When the cells were cultured in divalent cation-depleted medium, each dose-response curve was shifted to about a four-fold lower concentration range. Calprotectin was found to induce cell death even when the complex and the target cells were separated by dialysis membrane. A membrane-impermeable zinc chelator, diethylenetriamine pentaacetic acid (DTPA), also induced target cell apoptosis in a similar time-course as calprotectin. Moreover, the activities of calprotectin and DTPA were completely inhibited by the presence of zinc ions. These data indicate that calprotectin has higher specific activity to induce apoptosis than the Individual subunits, and that the mechanism is exclusion of zinc

  12. Zinc Ameliorate Oxidative Stress and Hormonal Disturbance Induced by Methomyl, Abamectin, and Their Mixture in Male Rats

    Directory of Open Access Journals (Sweden)

    Sameeh A. Mansour

    2017-12-01

    Full Text Available Exposure to mixtures of toxicants (e.g., pesticides is common in real life and a subject of current concern. The present investigation was undertaken to assess some toxicological effects in male rats following exposure to methomyl (MET, abamectin (ABM, and their combination (MET+ABM, and to evaluate the ameliorative effect of zinc co-administration. Three groups of rats were designated for MET, ABM, and the mixture treatments. Three other groups were designated for zinc in conjunction with the pesticides. Additionally, one group received water only (control, and the other represented a positive zinc treatment. The obtained results revealed that MET was acutely more toxic than ABM. The tested pesticides induced significant elevation in lipid peroxidation and catalase levels, while declined the levels of the other tested parameters e.g., Superoxide dismutase (SOD, Glutathione-S-transferase (GST, Glutathione peroxidase (GPx, Glutathione reductase (GR, Cytochrome P450 (CYP450, testosterone, and thyroxine. Biochemical alterations induced by the mixture were greater than those recorded for each of the individual insecticides. The joint action analysis, based on the obtained biochemical data, revealed the dominance of antagonistic action among MET and ABM. Zinc supplementation achieved noticeable ameliorative effects. It was concluded that zinc may act as a powerful antioxidant, especially in individuals who are occupationally exposed daily to low doses of such pesticides.

  13. Lower and upper chromatic numbers for BSTSs(2h - 1

    Directory of Open Access Journals (Sweden)

    Marco Buratti

    2001-08-01

    Full Text Available In [Discrete Math. 174, (1997 247-259] an infinite class of STSs(2h - 1 was found with the upper chromatic number not(χ=h. We prove that in this class, for all STSs(2h - 1 with h<10, the lower chromatic number coincides with the upper chromatic number, i.e. χ=not(χ=h and moreover, there exists a infinite sub-class of STSs with χ=not(χ=h for any value of h.

  14. Independence and interaction of luminance and chromatic contributions to spatial hyperacuity performance.

    Science.gov (United States)

    Cooper, Bonnie; Lee, Barry B

    2014-04-01

    Here we test interactions of luminance and chromatic input to spatial hyperacuity mechanisms. First, we tested alignment of luminance and chromatic gratings matched or mismatched in contrast polarity or grating type. Thresholds with matched gratings were low while all mismatched pairs were elevated. Second, we determined alignment acuity as a function of luminance or chromatic contrast alone or in the presence of constant contrast components of the other type. For in-phase components, performance followed the envelope of the more sensitive mechanism. However, polarity reversals revealed an asymmetric effect for luminance and chromatic conditions, which suggested that luminance can override chromatic mechanisms in hyperacuity; we interpret these findings in the context of spatial mechanisms.

  15. Minocycline Rescues from Zinc-Induced Nigrostriatal Dopaminergic Neurodegeneration: Biochemical and Molecular Interventions.

    Science.gov (United States)

    Kumar, Vinod; Singh, Brajesh Kumar; Chauhan, Amit Kumar; Singh, Deepali; Patel, Devendra Kumar; Singh, Chetna

    2016-07-01

    Accumulation of zinc (Zn) in dopaminergic neurons is implicated in Parkinson's disease (PD), and microglial activation plays a critical role in toxin-induced Parkinsonism. Oxidative stress is accused in Zn-induced dopaminergic neurodegeneration; however, its connection with microglial activation is still not known. This study was undertaken to elucidate the role and underlying mechanism of microglial activation in Zn-induced nigrostriatal dopaminergic neurodegeneration. Male Wistar rats were treated intraperitoneally with/without zinc sulphate (20 mg/kg) in the presence/absence of minocycline (30 mg/kg), a microglial activation inhibitor, for 2-12 weeks. While neurobehavioral and biochemical indexes of PD and number of dopaminergic neurons were reduced, the number of microglial cells was increased in the substantia nigra of the Zn-exposed animals. Similarly, Zn elevated lipid peroxidation (LPO) and activities of superoxide dismutase (SOD) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase; however, catalase activity was reduced. Besides, Zn increased an association of NADPH oxidase subunit p67(phox) with membrane, cytochrome c release from the mitochondria and cleavage of pro-caspase 3. Zn attenuated the expression of tyrosine hydroxylase (TH) and vesicular monoamine transporter-2 (VMAT-2) while augmented the expression of dopamine transporter (DAT) and heme oxygenase-1 (HO-1). Minocycline alleviated Zn-induced behavioural impairments, loss of TH-positive neurons, activated microglial cells and biochemical indexes and modulated the expression of studied genes/proteins towards normalcy. The results demonstrate that minocycline reduces the number of activated microglial cells and oxidative stress, which rescue from Zn-induced changes in the expression of monoamine transporter and nigrostriatal dopaminergic neurodegeneration.

  16. Color constancy by characterization of illumination chromaticity

    Science.gov (United States)

    Nikkanen, Jarno T.

    2011-05-01

    Computational color constancy algorithms play a key role in achieving desired color reproduction in digital cameras. Failure to estimate illumination chromaticity correctly will result in invalid overall colour cast in the image that will be easily detected by human observers. A new algorithm is presented for computational color constancy. Low computational complexity and low memory requirement make the algorithm suitable for resource-limited camera devices, such as consumer digital cameras and camera phones. Operation of the algorithm relies on characterization of the range of possible illumination chromaticities in terms of camera sensor response. The fact that only illumination chromaticity is characterized instead of the full color gamut, for example, increases robustness against variations in sensor characteristics and against failure of diagonal model of illumination change. Multiple databases are used in order to demonstrate the good performance of the algorithm in comparison to the state-of-the-art color constancy algorithms.

  17. Administration of Zinc plus Cyclo-(His-Pro Increases Hippocampal Neurogenesis in Rats during the Early Phase of Streptozotocin-Induced Diabetes

    Directory of Open Access Journals (Sweden)

    Bo Young Choi

    2017-01-01

    Full Text Available The effects of zinc supplementation on hippocampal neurogenesis in diabetes mellitus have not been studied. Herein, we investigated the effects of zinc plus cyclo-(His-Pro (ZC on neurogenesis occurring in the subgranular zone of dentate gyrus after streptozotocin (STZ-induced diabetes. ZC (27 mg/kg was administered by gavage once daily for one or six weeks from the third day after the STZ injection, and histological evaluation was performed at 10 (early phase or 45 (late phase days after STZ injection. We found that the proliferation of progenitor cells in STZ-induced diabetic rats showed an increase in the early phase. Additionally, ZC treatment remarkably increased the number of neural progenitor cells (NPCs and immature neurons in the early phase of STZ-induced diabetic rats. Furthermore, ZC treatment showed increased survival rate of newly generated cells but no difference in the level of neurogenesis in the late phase of STZ-induced diabetic rats. The present study demonstrates that zinc supplementation by ZC increases both NPCs proliferation and neuroblast production at the early phase of diabetes. Thus, this study suggests that zinc supplemented with a histidine/proline complex may have beneficial effects on neurogenesis in patients experiencing the early phase of Type 1 diabetes.

  18. The protective role of Gamma-Tocopherol and zinc cysteine against oxidative stress induced by gamma irradiation in albino rats

    International Nuclear Information System (INIS)

    Anis, L.M.

    2004-01-01

    The present study aimed to evaluate the capability of α tocopherol (naturally occurring antioxidant) and zinc cysteine against radiation induced oxidative stress. α Tocopherol was dissolved in corn oil and g, to the animals for ten successive days at a dose of 20 mg/kg b weight/day. Zinc cysteine was delivered to rats via intraperitoneal inject at a concentration of 25 mg/kg body weight/day for two successive days, rats were exposed to whole body gamma irradiation at a dose level of Gy. The activities of super oxide dismutase (SOD) and catalase and also concentrations of reduced glutathione (GSH) and malonaldehyde (Mi . were determined in the blood. The levels of metallothionein, zinc and copper were estimated in the serum, liver and kidney of the tested animals. The obtained results revealed that administration of a-tocopherol and zinc cysteine before gamma radiation exposure diminish significantly the decrease in blood SOD and catalase activities as compared to untreated irradiated rats. Also, the decrease in blood GSH concentration was less manifested and the decrease in the level of MDA was significant. The pre-gamma irradiation administration of zinc cysteine induced significant changes in the levels of metallothionein compared to both a-tocopherol supplemented and gamma irradiated rat groups. The amelioration occurred in the levels of zinc and copper postulated the positive role of vitamin E and zinc cysteine in alleviating all the levels of these elements

  19. The hot-atom chemistry of crystalline chromates. Chapter 8

    International Nuclear Information System (INIS)

    Collins, C.H.; Collins, K.E.

    1979-01-01

    Chromates in general and potassium chromate in particular, have been attractive as compounds for hot-atom chemical study because of the favourable nuclear properties of chromium, the great thermal and radiation stability of the compounds, the apparent structural simplicity of the crystals and the presumed known and simple chemistry of the expected recoil products. A wealth of information has been accumulated over the past 25 years, from which the anticipation of a straightforward chemistry has given way to an expanding realization that these systems are actually quite complex. More solid-state hot-atom chemical studies have dealt with potassium chromate than with any other compound. Thus, a major fraction of this review is given to this compound. The emphasis is on recent literature and on the pesent views of phenomena which affect the chemical fate of recoil chromium atoms in chromates. Many other data are tabulated so that the interested reader can speculate independently on the results of a wide variety of experiments. (Auth.)

  20. Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

    KAUST Repository

    Sun, Tiancheng; Peng, Yifan; Heidrich, Wolfgang

    2017-01-01

    Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

  1. Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

    KAUST Repository

    Sun, Tiancheng

    2017-12-25

    Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

  2. In vivo chromatic aberration in eyes implanted with intraocular lenses.

    Science.gov (United States)

    Pérez-Merino, Pablo; Dorronsoro, Carlos; Llorente, Lourdes; Durán, Sonia; Jiménez-Alfaro, Ignacio; Marcos, Susana

    2013-04-12

    To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-developed laser ray tracing (LRT) aberrometer was used to measure the optical aberrations, at 532 nm and 785 nm wavelengths. The monochromatic wave aberrations were described using a fifth-order Zernike polynomial expansion. The chromatic difference of focus was estimated as the difference between the equivalent spherical errors corresponding to each wavelength. Wave aberration measurements were highly reproducible. Except for the defocus term, no significant differences in high order aberrations (HOA) were found between wavelengths. The average chromatic difference of focus was 0.46 ± 0.15 diopters (D) in the Tecnis group, and 0.75 ± 0.12 D in the AcrySof group, and the difference was statistically significant (P Chromatic difference of focus in the AcrySof group was not statistically significantly different from the Longitudinal chromatic aberration (LCA) previously reported in a phakic population (0.78 ± 0.16 D). The impact of LCA on retinal image quality (measured in terms of Strehl ratio) was drastically reduced when considering HOA and astigmatism in comparison with a diffraction-limited eye, yielding the differences in retinal image quality between Tecnis and AcrySof IOLs not significant. LRT aberrometry at different wavelengths is a reproducible technique to evaluate the chromatic difference of focus objectively in eyes implanted with IOLs. Replacement of the crystalline lens by the IOL did not increase chromatic difference of focus above that of phakic eyes in any of the groups. The AcrySof group showed chromatic difference of focus values very similar to physiological values in

  3. Stereo chromatic contrast sensitivity model to blue-yellow gratings.

    Science.gov (United States)

    Yang, Jiachen; Lin, Yancong; Liu, Yun

    2016-03-07

    As a fundamental metric of human visual system (HVS), contrast sensitivity function (CSF) is typically measured by sinusoidal gratings at the detection of thresholds for psychophysically defined cardinal channels: luminance, red-green, and blue-yellow. Chromatic CSF, which is a quick and valid index to measure human visual performance and various retinal diseases in two-dimensional (2D) space, can not be directly applied into the measurement of human stereo visual performance. And no existing perception model considers the influence of chromatic CSF of inclined planes on depth perception in three-dimensional (3D) space. The main aim of this research is to extend traditional chromatic contrast sensitivity characteristics to 3D space and build a model applicable in 3D space, for example, strengthening stereo quality of 3D images. This research also attempts to build a vision model or method to check human visual characteristics of stereo blindness. In this paper, CRT screen was clockwise and anti-clockwise rotated respectively to form the inclined planes. Four inclined planes were selected to investigate human chromatic vision in 3D space and contrast threshold of each inclined plane was measured with 18 observers. Stimuli were isoluminant blue-yellow sinusoidal gratings. Horizontal spatial frequencies ranged from 0.05 to 5 c/d. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. According to the relationship between spatial frequency of inclined plane and horizontal spatial frequency, the chromatic contrast sensitivity characteristics in 3D space have been modeled based on the experimental data. The results show that the proposed model can well predicted human chromatic contrast sensitivity characteristics in 3D space.

  4. Zinc or copper deficiency-induced impaired inflammatory response to brain trauma may be caused by the concomitant metallothionein changes

    DEFF Research Database (Denmark)

    Penkowa, Milena; Giralt, M.; Thomsen, Pernille Sjølin

    2001-01-01

    , and this response was significantly blunted by zinc deficiency. The MT-III isoform was moderately increased by both TBI and zinc deficiency. TBI strongly increased oxidative stress levels, as demonstrated by malondialdehyde (MDA), protein tyrosine nitration (NITT), and nuclear factor kappaB (NF-kappaB) levels irs......, all of which were potentiated by zinc deficiency. Further analysis revealed unbalanced expression of prooxidant and antioxidant proteins besides MT, since the levels of inducible nitric oxide synthase (iNOS) and Cu,Zn-SOD were increased and decreased, respectively, by zinc deficiency. All......The role of zinc- and copper-deficient diets on the inflammatory response to traumatic brain injury (TBI) has been evaluated in adult rats. As expected, zinc deficiency decreased food intake and body weight gain, and the latter effect was higher than that observed in pair-fed rats. In noninjured...

  5. Spatio-chromatic adaptation via higher-order canonical correlation analysis of natural images.

    Science.gov (United States)

    Gutmann, Michael U; Laparra, Valero; Hyvärinen, Aapo; Malo, Jesús

    2014-01-01

    Independent component and canonical correlation analysis are two general-purpose statistical methods with wide applicability. In neuroscience, independent component analysis of chromatic natural images explains the spatio-chromatic structure of primary cortical receptive fields in terms of properties of the visual environment. Canonical correlation analysis explains similarly chromatic adaptation to different illuminations. But, as we show in this paper, neither of the two methods generalizes well to explain both spatio-chromatic processing and adaptation at the same time. We propose a statistical method which combines the desirable properties of independent component and canonical correlation analysis: It finds independent components in each data set which, across the two data sets, are related to each other via linear or higher-order correlations. The new method is as widely applicable as canonical correlation analysis, and also to more than two data sets. We call it higher-order canonical correlation analysis. When applied to chromatic natural images, we found that it provides a single (unified) statistical framework which accounts for both spatio-chromatic processing and adaptation. Filters with spatio-chromatic tuning properties as in the primary visual cortex emerged and corresponding-colors psychophysics was reproduced reasonably well. We used the new method to make a theory-driven testable prediction on how the neural response to colored patterns should change when the illumination changes. We predict shifts in the responses which are comparable to the shifts reported for chromatic contrast habituation.

  6. Moessbauer spectroscopy study of iron corrosion underneath painting system

    International Nuclear Information System (INIS)

    Nigam, R.K.; Hajela, B.P.; Sengupta, S.; Srivastava, B.C.; Gupta, K.N.

    1986-01-01

    The effect of pigments on the development of corrosion products between the painting system and metal surface when exposed to marine environments has been discussed. The pigments studied were: red mud zinc chromate, zinc chromate, red oxide zinc phosphate, manganese phosphate barium chromate and basic lead silico chromate. Moessbauer spectroscopy revealed that the upper rust layer in all the cases consisted of γ-Fe 2 O 3 , γ-FeOOH and α-FeOOH. The lower rust layer immediately in contact with the metal surface consisted of an asymmetrical doublet due to γ-FeOOH. (Auth.)

  7. Color-motion feature-binding errors are mediated by a higher-order chromatic representation.

    Science.gov (United States)

    Shevell, Steven K; Wang, Wei

    2016-03-01

    Peripheral and central moving objects of the same color may be perceived to move in the same direction even though peripheral objects have a different true direction of motion [Nature429, 262 (2004)10.1038/429262a]. The perceived, illusory direction of peripheral motion is a color-motion feature-binding error. Recent work shows that such binding errors occur even without an exact color match between central and peripheral objects, and, moreover, the frequency of the binding errors in the periphery declines as the chromatic difference increases between the central and peripheral objects [J. Opt. Soc. Am. A31, A60 (2014)JOAOD60740-323210.1364/JOSAA.31.000A60]. This change in the frequency of binding errors with the chromatic difference raises the general question of the chromatic representation from which the difference is determined. Here, basic properties of the chromatic representation are tested to discover whether it depends on independent chromatic differences on the l and the s cardinal axes or, alternatively, on a more specific higher-order chromatic representation. Experimental tests compared the rate of feature-binding errors when the central and peripheral colors had the identical s chromaticity (so zero difference in s) and a fixed magnitude of l difference, while varying the identical s level in center and periphery (thus always keeping the s difference at zero). A chromatic representation based on independent l and s differences would result in the same frequency of color-motion binding errors at everyslevel. The results are contrary to this prediction, thus showing that the chromatic representation at the level of color-motion feature binding depends on a higher-order chromatic mechanism.

  8. Total dominator chromatic number of a graph

    Directory of Open Access Journals (Sweden)

    Adel P. Kazemi

    2015-06-01

    Full Text Available Given a graph $G$, the total dominator coloring problem seeks a proper coloring of $G$ with the additional property that every vertex in the graph is adjacent to all vertices of a color class. We seek to minimize the number of color classes. We initiate to study this problem on several classes of graphs, as well as finding general bounds and characterizations. We also compare the total dominator chromatic number of a graph with the chromatic number and the total domination number of it.

  9. Exploring a Chromatic Oblique Effect

    National Research Council Canada - National Science Library

    Curran, Paul

    1997-01-01

    .... The purpose of this thesis was to investigate the role of certain spatial, temporal, and chromatic features on the human visual system and how these features may aid the quest for better camouflage. Methods...

  10. Genetic algorithm for chromaticity correction in diffraction limited storage rings

    Directory of Open Access Journals (Sweden)

    M. P. Ehrlichman

    2016-04-01

    Full Text Available A multiobjective genetic algorithm is developed for optimizing nonlinearities in diffraction limited storage rings. This algorithm determines sextupole and octupole strengths for chromaticity correction that deliver optimized dynamic aperture and beam lifetime. The algorithm makes use of dominance constraints to breed desirable properties into the early generations. The momentum aperture is optimized indirectly by constraining the chromatic tune footprint and optimizing the off-energy dynamic aperture. The result is an effective and computationally efficient technique for correcting chromaticity in a storage ring while maintaining optimal dynamic aperture and beam lifetime.

  11. Radiation induced traps of zinc phosphate and phosphide

    International Nuclear Information System (INIS)

    Murali, K.R.; Rao, D.R.

    1980-01-01

    Thermoluminescence (TL) glow curve (TGC) method has been used to study the traps produced by X-irradiation in Zn 3 (PO 4 ) 2 and Zn 3 P 2 . Prominent TL glow peaks were observed at 100 0 and 360 0 C for zinc phosphate while for zinc phosphide only one glow peak at 245 0 C was observed, and in the latter case the TL output was in general quite low compared to zinc phosphate. The TL spectra for both the glow peaks of zinc phosphate indicated emission band in the region around 560 nm, while for zinc phosphide the emission occurred at 575 nm (in the temperature region 200-270 0 C). The low temperature glow peaks below 270 0 C were less stable compared to those above 300 0 C and were completely destroyed when the irradiated samples were stored in darkness for 24 hr at room temperature. Shining by 470 nm light however produced preferential bleaching of the two TL peaks at 100 and 360 0 C with no effect on the 245 0 C glow peak of zinc phosphide. It is concluded that during heat treatment large numbers of Zn-vacancies are formed due to which complexes like Zn-P are produced by irradiation and the TL traps destroyed in a radiative recombination process are related with these complexes. (author)

  12. Chromatic characterization of a three-channel colorimeter using back-propagation neural networks

    Science.gov (United States)

    Pardo, P. J.; Pérez, A. L.; Suero, M. I.

    2004-09-01

    This work describes a method for the chromatic characterization of a three-channel colorimeter of recent design and construction dedicated to color vision research. The colorimeter consists of two fixed monochromators and a third monochromator interchangeable with a cathode ray tube or any other external light source. Back-propagation neural networks were used for the chromatic characterization to establish the relationship between each monochromator's input parameters and the tristimulus values of each chromatic stimulus generated. The results showed the effectiveness of this type of neural-network-based system for the chromatic characterization of the stimuli produced by any monochromator.

  13. Measuring chromatic aberrations in imaging systems using plasmonic nanoparticles.

    Science.gov (United States)

    Gennaro, Sylvain D; Roschuk, Tyler R; Maier, Stefan A; Oulton, Rupert F

    2016-04-01

    We demonstrate a method to measure chromatic aberrations of microscope objectives with metallic nanoparticles using white light. Extinction spectra are recorded while scanning a single nanoparticle through a lens's focal plane. We show a direct correlation between the focal wavelength and the longitudinal chromatic focal shift through our analysis of the variations between the scanned extinction spectra at each scan position and the peak extinction over the entire scan. The method has been tested on achromat and apochromat objectives using aluminum disks varying in size from 260-520 nm. Our method is straightforward, robust, low cost, and broadband with a sensitivity suitable for assessing longitudinal chromatic aberrations in high-numerical-aperture apochromatic corrected lenses.

  14. Chromate adsorption mechanism on nanodiamond-derived onion-like carbon

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Young-Jin [Center for Electronic Materials, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Choi, Keunsu [Computational Science Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Lee, Soonjae [Department of Earth and Environmental Sciences, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea (Korea, Republic of); Cho, Jung-Min [Center for Electronic Materials, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Department of Materials Science and Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul 120-749, Republic of Korea (Korea, Republic of); Choi, Heon-Jin [Department of Materials Science and Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul 120-749, Republic of Korea (Korea, Republic of); Hong, Seok Won [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Choi, Jae-Woo, E-mail: plead36@kist.re.kr [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Daejeon 305-350, Republic of Korea (Korea, Republic of); Mizuseki, Hiroshi, E-mail: mizuseki@kist.re.kr [Computational Science Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of); Lee, Wook-Seong, E-mail: wsleemk@gmail.com [Center for Electronic Materials, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea (Korea, Republic of)

    2016-12-15

    The onion-like carbon (OLC) was prepared as adsorbent and tested for the removal of chromate ions from aqueous solutions. The OLC was thermally derived from nanodiamond by vacuum annealing at 1000-2000 °C. An investigation was conducted the chromate adsorption mechanism of OLC, by analysing the temperature-dependent evolution of the various oxygen-carbon bonds and the chemisorbed water by X-ray photo electron spectroscopy, as well as by the first principle calculation of the bond energies for relevant bond configurations. The present work demonstrated the importance of the carbon-oxygen bond type and carbon dangling bonds for chromate adsorption, as well as for other anionic heavy metals adsorbed from wastewater and sewage.

  15. Monitoring of Optical Emission from High Temperature Plasma Based on Chromatic Modulation

    International Nuclear Information System (INIS)

    Dimitrios, Tomtsis

    2009-01-01

    An integrated experimental approach is presented for processing the optical emission produced from electric arc plasma. The method is based on chromatic modulation techniques to provide a holistic measurement of the persistence of particle decays within the environment of high power circuit breakers. Chromaticity changes in a number of chromatic parameters are related to changes in physical electric arc plasma environment (e.g. particle concentration). The results are in the form of chromatic maps which show how the overall electric arc plasma and its environment behave and respond. Such maps show the totality of information which can be accessed about the arcing event and the level of monitoring discrimination which is achievable with the chromatic methodology in a simple and easy to understand manner. The suggested method provides easier data analysis and high levels of data compression.

  16. Effect of radioactive chromate on the corrosion and polarisation of mild steel in sodium chloride solution

    International Nuclear Information System (INIS)

    Subramanyan, N.; Ramakrishnaiah, K.; Iyer, S.V.; Kapali, V.

    1980-01-01

    Corrosion tests of mild steel in 0.01% sodium chloride containing radioactive chromate and non-radioactive chromate have been carried out. It has been observed that the labelled sodium chromate has a deleterious effect on the inhibitive action of non-radioactive chromate. The effect of radioactive chromate on the potentiostatic polarization of m.s. in sodium chloride solution containing non-radioactive sodium chromate has also been studied. It is observed that both the cathodic and the anodic polarisation of the metal is diminished in the presence of radioactive chromate. The behaviour of the system in the presence of radioactive chromate is attributed both to the action of depolarisers produced by radiolysis of water and to the effect of gamma radiation on the metal. (author)

  17. CHROMAT trademark Version 1.1--Soil Chromium Attenuation Evaluation Model

    International Nuclear Information System (INIS)

    Felmy, A.R.; Rai, D.; Zachara, J.M.; Thapa, M.; Gold, M.

    1992-07-01

    This document is the user's manual and technical reference for the Soil Chromium Attenuation Model (CHROMAT trademark), a computer code designed to calculate both the dissolved Cr concentration and the amount of Cr attenuated in soils as a result of the geochemical reactions that occur as Cr-containing leachates migrate through porous soils. The dissolved Cr concentration and the amount of Cr attenuated are calculated using thermodynamic (mechanistic) data for aqueous complexation reactions, adsorption/ desorption reactions, and precipitation/dissolution reactions involving both CR(III) and Cr(VI) species. Use of this mechanistic approach means that CHROMAT trademark requires a minimum amount of site-specific data on leachate and soil characteristics. CHROMAT trademark is distributed in executable form for IBM and IBM-compatible personal computers through a license from the Electric Power Research Institute (EPRI). The user interacts with CHROMAT trademark using menu-driven screen displays. Interactive on-line help options are available. Output from the code can be obtained in tabular or graphic form. This manual describes the development of CHROMAT trademark, including experimental data development in support of the model and model validation studies. The thermodynamic data and computational algorithm are also described. Example problems and results are included

  18. On the capacity to the complexing of alkaline earth metal and magnesium chromates

    International Nuclear Information System (INIS)

    Orekhov, O.L.

    1978-01-01

    Considered is the capacity to the complexing of magnesium chromates and alkaline earth metal chromates with ammonium chromates in aqueous solutions. It has been established that the complexing of alkaline earth metal and magnesium chromates is effected by a nature of initial salts as well as their solubilities and the presence of crystallization water. Capacity of magnesium ions and alkaline rare earth metals to the complexing decreases in a series of Mg-Ca-Sr-Ba. Ca complexes exceed magnesium derivatives in respect of stability

  19. Effects of zinc supplementation and zinc chelation on in vitro β-cell function in INS-1E cells

    DEFF Research Database (Denmark)

    Nygaard, Sanne Bjørn; Larsen, Agnete; Knuhtsen, Astrid

    2014-01-01

    BACKGROUND: Zinc is essential for the activities of pancreatic β-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron......-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects β-cell function using INS-1E cells. RESULTS: Using INS-1E...... cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N',N-tektrakis(2-pyridylmethyl...

  20. Influence of soil zinc concentrations on zinc sensitivity and functional diversity of microbial communities

    International Nuclear Information System (INIS)

    Lock, K.; Janssen, C.R.

    2005-01-01

    Pollution induced community tolerance (PICT) is based on the phenomenon that toxic effects reduce survival of the most sensitive organisms, thus increasing community tolerance. Community tolerance for a contaminant is thus a strong indicator for the presence of that contaminant at the level of adverse concentrations. Here we assessed PICT in 11 soils contaminated with zinc runoff from galvanised electricity pylons and 11 reference soils sampled at 10 m distance from these pylons. Using PICT, the influence of background concentration and bioavailability of zinc on zinc sensitivity and functional diversity of microbial communities was assessed. Zinc sensitivity of microbial communities decreased significantly with increasing zinc concentrations in pore water and calcium chloride extracted fraction while no significant relationship was found with total zinc concentration in the soil. It was also found that functional diversity of microbial communities decreased with increasing zinc concentrations, indicating that increased tolerance is indeed an undesirable phenomenon when environmental quality is considered. The hypothesis that zinc sensitivity of microbial communities is related to background zinc concentration in pore water could not be confirmed. - Zinc sensitivity of microbial communities and functional diversity decrease with increasing zinc concentration in the pore water

  1. Zinc-induced protection against cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Early, J.L.; Schnell, R.C.

    1978-02-01

    Pretreatment of male rats with cadmium acetate potentiates the duration of hexobarbital hypnosis and inhibits the rate of hepatic microsomal drug metabolism. Pretreatment of rats with zinc acetate protects against these alterations in drug action elicited by cadmium.

  2. The lack of effects of zinc and nitric oxide in initial state of pilocarpine-induced seizures.

    Science.gov (United States)

    Noyan, Behzat; Jensen, Morten Skovgaard; Danscher, Gorm

    2007-07-01

    In this study we investigated whether intracerebroventricular (i.c.v.) injection of L-NAME (a nitric oxide synthase inhibitor) or CaEDTA (an extracellular zinc chelator) or the combination of the two could affect the initial phase of pilocarpine induced (2 h) seizures. Two groups of rats were used. Animals from both groups were given with i.c.v. injections of either saline (10 microl), L-NAME (150 microg/10 microl), CaEDTA (100 mM/10 microl) or L-NAME and CaEDTA. One group received pilocarpine HCl (380 mg/kg i.p.) the other served as control. Pilocarpine HCl was injected intraperitoneally 10 min later. The behavior of the animals was observed for 2h and the intensity of their seizures was scored. The rats were then sacrificed and their brains were removed and analyzed for zinc ions by using the immersion autometallography and the TSQ fluorescence staining. All the animals which received pilocarpine HCl developed seizures. Despite treatment with L-NAME and/or CaEDTA we found that the latency and the intensity of seizures were similar in both groups investigated. The distribution of stainable zinc ions and the intensity of staining in hippocampus were not affected by pilocarpine and found unchanged after L-NAME and/or CaEDTA injections in both the control animals and the pilocarpine treated animals. The data suggest that the nitric oxide system and zinc ions do not affect pilocarpine-induced seizures in their initial state.

  3. Efficient removal of chromate and arsenate from individual and mixed system by malachite nanoparticles

    International Nuclear Information System (INIS)

    Saikia, Jiban; Saha, Bedabrata; Das, Gopal

    2011-01-01

    Graphical abstract: Malachite nanoparticles of 100-150 nm, have been efficiently and for the first time used as an adsorbent for the removal of toxic arsenate and chromate in pH range 4-5. - Abstract: Malachite nanoparticles of 100-150 nm have been efficiently and for the first time used as an adsorbent for the removal of toxic arsenate and chromate. We report a high adsorption capacity for chromate and arsenate on malachite nanoparticle from both individual and mixed solution in pH ∼4-5. However, the adsorption efficiency decreases with the increase of solution pH. Batch studies revealed that initial pH, temperature, malachite nanoparticles dose and initial concentration of chromate and arsenate were important parameters for the adsorption process. Thermodynamic analysis showed that adsorption of chromate and arsenate on malachite nanoparticles is endothermic and spontaneous. The adsorption of these anions has also been investigated quantitatively with the help of adsorption kinetics, isotherm, and selectivity coefficient (K) analysis. The adsorption data for both chromate and arsenate were fitted well in Langmuir isotherm and preferentially followed the second order kinetics. The binding affinity of chromate is found to be slightly higher than arsenate in a competitive adsorption process which leads to the comparatively higher adsorption of chromate on malachite nanoparticles surface.

  4. The beneficial effects of zinc on diabetes-induced kidney damage in murine rodent model of type 1 diabetes mellitus.

    Science.gov (United States)

    Yang, Fan; Li, Bing; Dong, Xiaoming; Cui, Wenpeng; Luo, Ping

    2017-07-01

    Diabetes mellitus is a chronic multi-factorial metabolic disorder resulting from impaired glucose homeostasis. Zinc is a key co-factor for the correct functioning of anti-oxidant enzymes. Zinc deficiency therefore, impairs their synthesis, leading to increased oxidative stress within cells. Zinc deficiency occurs commonly in diabetic patients. The aim of this study is to investigate the effects of varying concentrations of zinc on diabetic nephropathy (DN) and the underlying mechanisms involved. FVB male mice aged 8 weeks were injected intraperitoneally with multiple low-dose streptozotocin at a concentration of 50mg/kg body weight daily for 5 days. Diabetic and age-matched control mice were treated with special diets supplemented with zinc at varying concentrations (0.85mg/kg, 30mg/kg, 150mg/kg) for 3 months. The mice were fed with zinc diets to mimic the process of oral administration of zinc in human. Zinc deficiency to some extent aggravated the damage of diabetic kidney. Feeding with normal (30mg/kg zinc/kg diet) and especially high (150mg/kg zinc/kg diet) concentration zinc could protect the kidney against diabetes-induced damage. The beneficial effects of zinc on DN are achieved most likely due to the upregulation of Nrf2 and its downstream factors NQO1, SOD1, SOD2. Zinc upregulated the expression of Akt phosphorylation and GSK-3β phosphorylation, resulting in a reduction in Fyn nuclear translocation and export of Nrf2 to the cytosol. Thus, regular monitoring and maintaining of adequate levels of zinc are recommended in diabetic individuals in order to delay the development of DN. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Very-long-term and short-term chromatic adaptation: are their influences cumulative?

    Science.gov (United States)

    Belmore, Suzanne C; Shevell, Steven K

    2011-02-09

    Very-long-term (VLT) chromatic adaptation results from exposure to an altered chromatic environment for days or weeks. Color shifts from VLT adaptation are observed hours or days after leaving the altered environment. Short-term chromatic adaptation, on the other hand, results from exposure for a few minutes or less, with color shifts measured within seconds or a few minutes after the adapting light is extinguished; recovery to the pre-adapted state is complete in less than an hour. Here, both types of adaptation were combined. All adaptation was to reddish-appearing long-wavelength light. Shifts in unique yellow were measured following adaptation. Previous studies demonstrate shifts in unique yellow due to VLT chromatic adaptation, but shifts from short-term chromatic adaptation to comparable adapting light can be far greater than from VLT adaptation. The question considered here is whether the color shifts from VLT adaptation are cumulative with large shifts from short-term adaptation or, alternatively, does simultaneous short-term adaptation eliminate color shifts caused by VLT adaptation. The results show the color shifts from VLT and short-term adaptation together are cumulative, which indicates that both short-term and very-long-term chromatic adaptation affect color perception during natural viewing. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Localized chromaticity correction of low-beta insertions in storage rings

    International Nuclear Information System (INIS)

    Donald, M.; Helm, R.; Irwin, J.; Moshammer, H.; Sullivan, M.; Forest, E.; Robin, D.; Zholents, A.

    1993-01-01

    The correction of the chromaticity of low-beta insertions in the storage rings is usually made with sextupole lenses in the ring's arcs. When decreasing the beta functions at the insertion point (IP), this technique becomes fairly ineffective, since it fails to properly correct the higher order chromatic aberrations. Here the authors consider the approach where the chromatic effects of the quadrupole lenses generating low beta functions at the IP are corrected locally with two families of sextupoles, one family for each plane. Each family has two pairs of sextupoles which are located symmetrically on both sides of the IP. The sextupole-like aberrations of individual sextupoles are eliminated by utilizing optics forming a -I transformation between sextupoles in the pair. The optics also includes bending magnets which preserve equal dispersion functions at the two sextupoles in each pair. At sextupoles in one family, the vertical beta function is made large and the horizontal is made small. The situation is reversed in the sextupoles of the other family. The betatron phase advances from the IP to the sextupoles are chosen to eliminate a second order chromatic aberration. The application of the localized chromatic correction is demonstrated using as an example the lattice design for the Low Energy Ring of the SLAC/LBL/LLNL PEP-II B Factory

  7. Localized chromaticity correction of low-beta insertions in storage rings

    International Nuclear Information System (INIS)

    Donald, M.; Helm, R.; Irwin, J.; Moshammer, H.; Sullivan, M.; Forest, E.; Robin, D.; Zholents, A.

    1993-04-01

    The correction of the chromaticity of low-beta insertions in the storage rings is usually made with sextupole lenses in the ring's arcs. When decreasing the beta functions at the insertion point (IP), this technique becomes fairly ineffective, since it fails to properly correct the higher order chromatic aberrations. Here we consider the approach where the chromatic effects of the quadrupole lenses generating low beta functions at the IP are corrected locally with two families of sextupoles, one family for each plane. Each family has two pairs of sextupoles which are located symmetrically on both sides of the IP. The sextupole-like aberrations of individual sextupoles are eliminated by utilizing optics forming a -I transformation between sextupoles in the pair. The optics also includes bending magnets which preserve equal dispersion functions at the two sextupoles in each pair. At sextupoles in one family, the vertical beta function is made large and the horizontal is made small. The situation is reversed in the sextupoles of the other family. The betatron phase advances from the IP to the sextupoles are chosen to eliminate a second order chromatic aberration. The application of the localized chromatic correction is demonstrated using as an example the lattice design for the Low Energy Ring of the SLAC/LBL/LLNL PEP-II B Factory

  8. Primary chromatic aberration elimination via optimization work with genetic algorithm

    Science.gov (United States)

    Wu, Bo-Wen; Liu, Tung-Kuan; Fang, Yi-Chin; Chou, Jyh-Horng; Tsai, Hsien-Lin; Chang, En-Hao

    2008-09-01

    Chromatic Aberration plays a part in modern optical systems, especially in digitalized and smart optical systems. Much effort has been devoted to eliminating specific chromatic aberration in order to match the demand for advanced digitalized optical products. Basically, the elimination of axial chromatic and lateral color aberration of an optical lens and system depends on the selection of optical glass. According to reports from glass companies all over the world, the number of various newly developed optical glasses in the market exceeds three hundred. However, due to the complexity of a practical optical system, optical designers have so far had difficulty in finding the right solution to eliminate small axial and lateral chromatic aberration except by the Damped Least Squares (DLS) method, which is limited in so far as the DLS method has not yet managed to find a better optical system configuration. In the present research, genetic algorithms are used to replace traditional DLS so as to eliminate axial and lateral chromatic, by combining the theories of geometric optics in Tessar type lenses and a technique involving Binary/Real Encoding, Multiple Dynamic Crossover and Random Gene Mutation to find a much better configuration for optical glasses. By implementing the algorithms outlined in this paper, satisfactory results can be achieved in eliminating axial and lateral color aberration.

  9. Luminescence properties of Dy3+ doped lithium zinc borosilicate glasses for photonic applications

    Directory of Open Access Journals (Sweden)

    N. Jaidass

    2018-03-01

    Full Text Available Different concentrations of Dy3+ ions doped lithium zinc borosilicate glasses of chemical composition (30-x B2O3 - 25 SiO2 -10 Al2O3 -30 LiF - 5 ZnO - x Dy2O3 (x = 0, 0.1, 0.5, 1.0 and 2.0 mol% were prepared by the melt quenching technique. The prepared glasses were investigated through X-ray diffraction, optical absorption, photoluminescence and decay measurements. Intensities of absorption bands expressed in terms of oscillator strengths (f were used to determine the Judd-Ofelt (J-O intensity parameters Ωλ (λ = 2, 4 and 6. The evaluated J-O parameters were used to determine the radiative parameters such as transition probabilities (AR, total transition probability rate (AT, radiative lifetime (τR and branching ratios (βR for the excited 4F9/2 level of Dy3+ ions. The chromaticity coordinates determined from the emission spectra were found to be located in the white light region of CIE chromaticity diagram. Keywords: Condensed matter physics, Engineering, Materials science

  10. Optical and chromaticity characteristics of adsorbates of the thorium complex of arsenazo I

    International Nuclear Information System (INIS)

    Ivanov, V.M.; Figurovskaya, V.N.; Ershova, N.I.

    2003-01-01

    Immobilized reagent Arsenazo I was used for the direct determination of trace thorium by diffuse reflectance spectrometry and chromaticity measurements. Silica gel Silochrom C-120 and C 18 were studied as supports. Optimal conditions of sorption were found. The dependence of chromaticity functions (chromaticity coordinates, color lightness, saturation, yellowness, and whiteness) on different chemical factors was studied. Advantages of the use of yellowness, color hue, and total color difference in comparison with other chromaticity functions was demonstrated. A method was developed for the determination of thorium with a detection limit of 0.02 μg/mL [ru

  11. Radiation induced structural changes in alpha-copper-zinc alloys

    International Nuclear Information System (INIS)

    Schuele, W.; Gieb, M.

    1991-01-01

    During irradiation of alpha-copper-zinc alloys with high energy electrons and protons a decrease of the electrical resistivity due to an increase of the degree of short range order is observed through radiation enhanced diffusion followed by an increase of the electrical resistivity through the formation of radiation induced interstitial clusters. The initial formation rate of interstitial clusters increases about linearly with the displacement rate for electron and proton irradiation. The largest initial formation rate is found between 60 and 130 0 C becoming negligibly small above 158 0 C and decreases drastically below 60 0 C. The dynamic steady state interstitial cluster concentration increases with decreasing irradiation temperature in the investigated temperature range between 158 and 40 0 C. Above 158 0 C the formation rate of interstitial clusters is negligibly small. Thus the transition temperature for radiation induced interstitial cluster formation is 158 0 C, depending mainly on the migration activation energy of vacancies. The radiation induced interstitial clusters are precipitates in those alloys in which the diffusion rate of the undersized component atoms via an interstitialcy diffusion mechanism is larger than that of the other atoms

  12. Efficient removal of chromate and arsenate from individual and mixed system by malachite nanoparticles.

    Science.gov (United States)

    Saikia, Jiban; Saha, Bedabrata; Das, Gopal

    2011-02-15

    Malachite nanoparticles of 100-150 nm have been efficiently and for the first time used as an adsorbent for the removal of toxic arsenate and chromate. We report a high adsorption capacity for chromate and arsenate on malachite nanoparticle from both individual and mixed solution in pH ∼4-5. However, the adsorption efficiency decreases with the increase of solution pH. Batch studies revealed that initial pH, temperature, malachite nanoparticles dose and initial concentration of chromate and arsenate were important parameters for the adsorption process. Thermodynamic analysis showed that adsorption of chromate and arsenate on malachite nanoparticles is endothermic and spontaneous. The adsorption of these anions has also been investigated quantitatively with the help of adsorption kinetics, isotherm, and selectivity coefficient (K) analysis. The adsorption data for both chromate and arsenate were fitted well in Langmuir isotherm and preferentially followed the second order kinetics. The binding affinity of chromate is found to be slightly higher than arsenate in a competitive adsorption process which leads to the comparatively higher adsorption of chromate on malachite nanoparticles surface. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Experimental and theoretical approach on the optical properties of zinc borotellurite glass doped with dysprosium oxide

    Science.gov (United States)

    Halimah, M. K.; Ami Hazlin, M. N.; Muhammad, F. D.

    2018-04-01

    A series of glass samples with chemical formula {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1 - x(Dy2O3)x where x = 0.01, 0.02, 0.03, 0.04 and 0.05 M fraction were synthesized through conventional melt-quenching method. The most common way to fabricate a glass material is by fusion of two or more component oxides followed by their quenching. This technique is known as melt-quenching technique. Kaur et al. (2016) [1] highlighted that the melt-quenching method able to enhance the mechanical properties like hardness and flexural strength of the material. The nature of the glass systems is proven to be amorphous based on the XRD pattern. The FTIR spectra of the glass systems confirm the existence of five bands which are assigned for the BO4, BO3, TeO4 and TeO3 vibrational groups. The density of the glass systems is increased with the addition of Dy2O3 while the molar volume is found to be inversely proportional to the density of the proposed glass. The optical properties of the glasses are determined through the absorption spectra obtained from the UV-VIS spectrophotometer. From the absorption spectra, the indirect and direct optical band gaps and the Urbach energy are found to be inversely proportional to each other. As the molar fraction of the Dy2O3 increased, the optical band gaps are observed to increase as opposed to the Urbach energy. For this glass system, the values of refractive index, electronic polarizability, oxide ion polarizability and the optical basicity are found to decrease as the addition of the dysprosium oxide is increased. From the emission spectra, two intense blue and yellow emission bands are observed, which correspond to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3 + ions respectively. The CIE chromaticity coordinates of the zinc borotellurite glass systems are found to be located in the white light region. Generation of white light The generation of the white light can be achieved by using two emission bands which comprise of the yellow

  14. Chromatic confocal microscopy for multi-depth imaging of epithelial tissue

    Science.gov (United States)

    Olsovsky, Cory; Shelton, Ryan; Carrasco-Zevallos, Oscar; Applegate, Brian E.; Maitland, Kristen C.

    2013-01-01

    We present a novel chromatic confocal microscope capable of volumetric reflectance imaging of microstructure in non-transparent tissue. Our design takes advantage of the chromatic aberration of aspheric lenses that are otherwise well corrected. Strong chromatic aberration, generated by multiple aspheres, longitudinally disperses supercontinuum light onto the sample. The backscattered light detected with a spectrometer is therefore wavelength encoded and each spectrum corresponds to a line image. This approach obviates the need for traditional axial mechanical scanning techniques that are difficult to implement for endoscopy and susceptible to motion artifact. A wavelength range of 590-775 nm yielded a >150 µm imaging depth with ~3 µm axial resolution. The system was further demonstrated by capturing volumetric images of buccal mucosa. We believe these represent the first microstructural images in non-transparent biological tissue using chromatic confocal microscopy that exhibit long imaging depth while maintaining acceptable resolution for resolving cell morphology. Miniaturization of this optical system could bring enhanced speed and accuracy to endomicroscopic in vivo volumetric imaging of epithelial tissue. PMID:23667789

  15. The effect of chromatic decoherence on transverse injection oscillation damping

    International Nuclear Information System (INIS)

    Jackson, G.P.

    1993-01-01

    In order to eliminate or reduce transverse emittance growth during transfers between accelerators, transverse damper systems are used to eliminate residual dipole oscillations before phase space dilution takes place. In transfers where the target accelerator has high chromaticity or the beam has a large momentum spread, phase space dilution due to chromatic decoherence can take place on a scale short compared to the damping time of the transverse injection oscillation damper. The effect of the damper on the beam phase space is not clear while the coherent oscillation is suppressed by this decoherence. The purpose of this paper is to quantify the effectiveness of dampers at eliminating emittance blowup at transfers in the presence of chromatic decoherence

  16. IMPACT OF ATMOSPHERIC CHROMATIC EFFECTS ON WEAK LENSING MEASUREMENTS

    International Nuclear Information System (INIS)

    Meyers, Joshua E.; Burchat, Patricia R.

    2015-01-01

    Current and future imaging surveys will measure cosmic shear with statistical precision that demands a deeper understanding of potential systematic biases in galaxy shape measurements than has been achieved to date. We use analytic and computational techniques to study the impact on shape measurements of two atmospheric chromatic effects for ground-based surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope (LSST): (1) atmospheric differential chromatic refraction and (2) wavelength dependence of seeing. We investigate the effects of using the point-spread function (PSF) measured with stars to determine the shapes of galaxies that have different spectral energy distributions than the stars. We find that both chromatic effects lead to significant biases in galaxy shape measurements for current and future surveys, if not corrected. Using simulated galaxy images, we find a form of chromatic “model bias” that arises when fitting a galaxy image with a model that has been convolved with a stellar, instead of galactic, PSF. We show that both forms of atmospheric chromatic biases can be predicted (and corrected) with minimal model bias by applying an ordered set of perturbative PSF-level corrections based on machine-learning techniques applied to six-band photometry. Catalog-level corrections do not address the model bias. We conclude that achieving the ultimate precision for weak lensing from current and future ground-based imaging surveys requires a detailed understanding of the wavelength dependence of the PSF from the atmosphere, and from other sources such as optics and sensors. The source code for this analysis is available at https://github.com/DarkEnergyScienceCollaboration/chroma

  17. IMPACT OF ATMOSPHERIC CHROMATIC EFFECTS ON WEAK LENSING MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, Joshua E.; Burchat, Patricia R., E-mail: jmeyers314@gmail.com [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA 94305 (United States)

    2015-07-10

    Current and future imaging surveys will measure cosmic shear with statistical precision that demands a deeper understanding of potential systematic biases in galaxy shape measurements than has been achieved to date. We use analytic and computational techniques to study the impact on shape measurements of two atmospheric chromatic effects for ground-based surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope (LSST): (1) atmospheric differential chromatic refraction and (2) wavelength dependence of seeing. We investigate the effects of using the point-spread function (PSF) measured with stars to determine the shapes of galaxies that have different spectral energy distributions than the stars. We find that both chromatic effects lead to significant biases in galaxy shape measurements for current and future surveys, if not corrected. Using simulated galaxy images, we find a form of chromatic “model bias” that arises when fitting a galaxy image with a model that has been convolved with a stellar, instead of galactic, PSF. We show that both forms of atmospheric chromatic biases can be predicted (and corrected) with minimal model bias by applying an ordered set of perturbative PSF-level corrections based on machine-learning techniques applied to six-band photometry. Catalog-level corrections do not address the model bias. We conclude that achieving the ultimate precision for weak lensing from current and future ground-based imaging surveys requires a detailed understanding of the wavelength dependence of the PSF from the atmosphere, and from other sources such as optics and sensors. The source code for this analysis is available at https://github.com/DarkEnergyScienceCollaboration/chroma.

  18. Correction of chromatic abberation in electrostatic lense systems containing quadrupoles

    International Nuclear Information System (INIS)

    Baranova, L.A.; Ul'yanova, N.S.; Yavor, S.Ya.

    1991-01-01

    Possibility of chromatic abberation correction in immersion systems consisting of axysimmetric and quadrupole lenses is shown. Concrete examples are presented. A number of new directions in science and technique, using ion beams are intensively developed presently. When using them accute necessity arises in chromatic abberation correction, while large-scale energy scattering is observed as a rule in such cases

  19. The main injector chromaticity correction sextupole magnets: Measurements and operating schemes

    International Nuclear Information System (INIS)

    Bhat, C.M.; Bogacz, A.; Brown, B.C.; Harding, D.J.; Fang, S.J.; Martin, P.S.; Glass, H.D.; Sim, J.

    1995-05-01

    The Fermilab Main Injector (FMI) is a high intensity proton synchrotron which will be used to accelerate protons and antiprotons from 8.9 GeV/c to 150 GeV/c. The natural chromaticities of the machine for the horizontal and the vertical Planes are -33.6 and -33.9 respectively. The Δp/p of the beam at injection is about 0.002. The chromaticity requirements of the FMI, are primarily decided by the Δp/p = 0.002 of the beam at injection. This limits the final chromaticity of the FMI to be ±5 units. To correct the chromaticity in the FMI two families of sextupole magnets will be installed in the lattice, one for each plane. A sextupole magnet suitable for the FMI needs has been designed and a number of them are being built. New chromaticity compensation schemes have been worked out in the light of recently proposed faster acceleration ramps. On an R/D sextupole magnet the low current measurements have been carried out to determine the electrical properties. Also, using a Morgan coil, measurements have been performed to determine the higher ordered multipole components up to 18-poles. An overview of these result are presented here

  20. UHF Signal Processing and Pattern Recognition of Partial Discharge in Gas-Insulated Switchgear Using Chromatic Methodology.

    Science.gov (United States)

    Wang, Xiaohua; Li, Xi; Rong, Mingzhe; Xie, Dingli; Ding, Dan; Wang, Zhixiang

    2017-01-18

    The ultra-high frequency (UHF) method is widely used in insulation condition assessment. However, UHF signal processing algorithms are complicated and the size of the result is large, which hinders extracting features and recognizing partial discharge (PD) patterns. This article investigated the chromatic methodology that is novel in PD detection. The principle of chromatic methodologies in color science are introduced. The chromatic processing represents UHF signals sparsely. The UHF signals obtained from PD experiments were processed using chromatic methodology and characterized by three parameters in chromatic space ( H , L , and S representing dominant wavelength, signal strength, and saturation, respectively). The features of the UHF signals were studied hierarchically. The results showed that the chromatic parameters were consistent with conventional frequency domain parameters. The global chromatic parameters can be used to distinguish UHF signals acquired by different sensors, and they reveal the propagation properties of the UHF signal in the L-shaped gas-insulated switchgear (GIS). Finally, typical PD defect patterns had been recognized by using novel chromatic parameters in an actual GIS tank and good performance of recognition was achieved.

  1. Lung injury, inflammation and Akt signaling following inhalation of particulate hexavalent chromium

    International Nuclear Information System (INIS)

    Beaver, Laura M.; Stemmy, Erik J.; Constant, Stephanie L.; Schwartz, Arnold; Little, Laura G.; Gigley, Jason P.; Chun, Gina; Sugden, Kent D.

    2009-01-01

    Certain particulate hexavalent chromium [Cr(VI)] compounds are human respiratory carcinogens that release genotoxic soluble chromate, and are associated with fibrosis, fibrosarcomas, adenocarcinomas and squamous cell carcinomas of the lung. We postulate that inflammatory processes and mediators may contribute to the etiology of Cr(VI) carcinogenesis, however the immediate (0-24 h) pathologic injury and immune responses after exposure to particulate chromates have not been adequately investigated. Our aim was to determine the nature of the lung injury, inflammatory response, and survival signaling responses following intranasal exposure of BALB/c mice to particulate basic zinc chromate. Factors associated with lung injury, inflammation and survival signaling were measured in airway lavage fluid and in lung tissue. A single chromate exposure induced an acute immune response in the lung, characterized by a rapid and significant increase in IL-6 and GRO-α levels, an influx of neutrophils, and a decline in macrophages in lung airways. Histological examination of lung tissue in animals challenged with a single chromate exposure revealed an increase in bronchiolar cell apoptosis and mucosal injury. Furthermore, chromate exposure induced injury and inflammation that progressed to alveolar and interstitial pneumonitis. Finally, a single Cr(VI) challenge resulted in a rapid and persistent increase in the number of airways immunoreactive for phosphorylation of the survival signaling protein Akt, on serine 473. These data illustrate that chromate induces both survival signaling and an inflammatory response in the lung, which we postulate may contribute to early oncogenesis

  2. Spectrally-balanced chromatic approach-lighting system

    Science.gov (United States)

    Chase, W. D.

    1977-01-01

    Approach lighting system employing combinations of red and blue lights reduces problem of color-based optical illusions. System exploits inherent chromatic aberration of eye to create three-dimensional effect, giving pilot visual clues of position.

  3. Closure plan for the Test Area North-726 chromate water storage and Test Area North-726A chromate treatment units

    International Nuclear Information System (INIS)

    Smith, P.J.; Van Brunt, K.M.

    1992-11-01

    This document describes the proposed plan for closure of the Test Area North-726 chromate water storage and Test Area North-726A chromate treatment units at the Idaho National Engineering Laboratory in accordance with the Resource Conservation and Recovery Act interim status closure requirements. The location, size, capacity, and history of the units are described, and their current status is discussed. The units will be closed by treating remaining waste in storage, followed by thorough decontamination of the systems. Sufficient sampling and analysis, and documentation of all activities will be performed to demonstrate clean closure

  4. Regulation of S100A8/A9 (calprotectin) binding to tumor cells by zinc ion and its implication for apoptosis-inducing activity.

    Science.gov (United States)

    Nakatani, Yuichi; Yamazaki, Masatoshi; Chazin, Walter J; Yui, Satoru

    2005-10-24

    S100A8/A9 (calprotectin), which is released by neutrophils under inflammatory conditions, has the capacity to induce apoptosis in various cells. We previously reported that S100A8/A9 induces apoptosis of EL-4 lymphoma cells via the uptake of extracellular zinc in a manner similar to DTPA, a membrane-impermeable zinc chelator. In this study, S100A8/A9-induced apoptosis was examined in several cell lines that are weakly sensitive to DTPA, suggesting S100A8/A9 is directly responsible for apoptosis in these cells. Since zinc inhibits apoptosis of MM46, one of these cells, the regulation by zinc of the capacity of S100A8/A9 to bind MM46 cells was studied. When MM46 cells were incubated with S100A8/A9 in standard or zinc-depleted medium, the amounts of S100A8/A9 bound to cells was markedly lower at 3 h than at 1 h. In contrast, when MM46 cells were incubated with S100A8/A9 in the presence of high levels of zinc, binding to cells was the same at 1 and 3 h. When the cells were permeabilized with saponin prior to analysis, a larger amount of cell-associated S100A8/A9 was detected at 3 h. The amount was further increased in cells treated with chloroquine, suggesting that S100A8/A9 was internalized and degraded in lysosomes. Although it has been reported that S100A8/A9 binds to heparan sulfate on cell membranes, the amount of S100A8/A9 bound to MM46 cells was not reduced by heparinase treatment, but was reduced by trypsin treatment. These results suggest that S100A8/A9 induces apoptosis by direct binding to MM46 cells, and that this activity is regulated by zinc.

  5. Detection and Removal of Chromatic Moving Shadows in Surveillance Scenarios

    DEFF Research Database (Denmark)

    Casado, Ivan Huerta; Holte, Michael Boelstoft; Moeslund, Thomas B.

    2009-01-01

    . Consequently, umbra shadows are usually detected as part of moving objects. In this paper we present a novel technique based on gradient and colour models for separating chromatic moving cast shadows from detected moving objects. Firstly, both a chromatic invariant colour cone model and an invariant gradient...

  6. Achromatic-chromatic colorimetric sensors for on-off type detection of analytes.

    Science.gov (United States)

    Heo, Jun Hyuk; Cho, Hui Hun; Lee, Jin Woong; Lee, Jung Heon

    2014-12-21

    We report the development of achromatic colorimetric sensors; sensors changing their colors from achromatic black to other chromatic colors. An achromatic colorimetric sensor was prepared by mixing a general colorimetric indicator, whose color changes between chromatic colors, and a complementary colored dye with no reaction to the targeted analyte. As the color of an achromatic colorimetric sensor changes from black to a chromatic color, the color change could be much easily recognized than general colorimetric sensors with naked eyes. More importantly, the achromatic colorimetric sensors enable on-off type recognition of the presence of analytes, which have not been achieved from most colorimetric sensors. In addition, the color changes from some achromatic colorimetric sensors (achromatic Eriochrome Black T and achromatic Benedict's solution) could be recognized with naked eyes at much lower concentration ranges than normal chromatic colorimetric sensors. These results provide new opportunities in the use of colorimetric sensors for diverse applications, such as harsh industrial, environmental, and biological detection.

  7. Zinc Vacancy-Induced Room-Temperature Ferromagnetism in Undoped ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Hongtao Ren

    2012-01-01

    Full Text Available Undoped ZnO thin films are prepared by polymer-assisted deposition (PAD and treated by postannealing at different temperatures in oxygen or forming gases (95%  Ar+5% H2. All the samples exhibit ferromagnetism at room temperature (RT. SQUID and positron annihilation measurements show that post-annealing treatments greatly enhance the magnetizations in undoped ZnO samples, and there is a positive correlation between the magnetization and zinc vacancies in the ZnO thin films. XPS measurements indicate that annealing also induces oxygen vacancies that have no direct relationship with ferromagnetism. Further analysis of the results suggests that the ferromagnetism in undoped ZnO is induced by Zn vacancies.

  8. Correcting the Chromatic Aberration in Barrel Distortion of Endoscopic Images

    Directory of Open Access Journals (Sweden)

    Y. M. Harry Ng

    2003-04-01

    Full Text Available Modern endoscopes offer physicians a wide-angle field of view (FOV for minimally invasive therapies. However, the high level of barrel distortion may prevent accurate perception of image. Fortunately, this kind of distortion may be corrected by digital image processing. In this paper we investigate the chromatic aberrations in the barrel distortion of endoscopic images. In the past, chromatic aberration in endoscopes is corrected by achromatic lenses or active lens control. In contrast, we take a computational approach by modifying the concept of image warping and the existing barrel distortion correction algorithm to tackle the chromatic aberration problem. In addition, an error function for the determination of the level of centroid coincidence is proposed. Simulation and experimental results confirm the effectiveness of our method.

  9. Synthesis and characterization of 5,7-dimethyl-8-hydroxyquinoline and 2-(2-pyridyl)benzimidazole complexes of zinc(II) for optoelectronic application

    Science.gov (United States)

    Singh, Kapoor; Kumar, Amit; Srivastava, Ritu; Kadyan, Partap S.; Kamalasanan, Modeeparampil N.; Singh, Ishwar

    2011-11-01

    Bis(5,7-dimethyl-8-hydroxyquinolinato)zinc(II) (Me 2q) 2Zn and 5,7-dimethyl-8-hydroxyquinolinato(2-(2-pyridyl)benzimidazole) zinc(II) Me 2q(pbi)Zn have been synthesized and characterized by various techniques. These metal complexes have high thermal stability (>300 °C) and high glass transition temperatures (>150 °C). The vacuum deposited films of these materials show good film forming property and are suitable for opto-electronic applications. Multilayered organic electroluminescent (EL) devices have been fabricated having structure ITO/α-NPD/zinc complex/BCP/Alq 3/LiF/Al, which produce emission with chromaticity having Commission Internationale d'Eclairage (CIE) coordinates x = 0.506 and y = 0.484 for (Me 2q) 2Zn; x = 0.47 and y = 0.52 for (Me 2q)(pbi)Zn complex. The electroluminescence spectra show peak emission centered at 572 and 561 nm respectively for these materials.

  10. Alterations in Somatostatin Cells and Biochemical Parameters Following Zinc Supplementation in Gastrointestinal Tissue of St reptozotocin-Induced Diabetic Rats

    International Nuclear Information System (INIS)

    Bolkent, Sema; Bolkent, Sehnaz; Yanardag, Refiye; Mutlu, Ozgur; Yildirim, Sukriye

    2006-01-01

    Chronic hyperglycemia in diabetes is a major causative factor of free radical generation which further leads to many secondary diabetic complications via the damage to cellular proteins, membrane lipids, and nucleic acids. Zinc is an essential trace element in all living systems and plays a structural role in many proteins and enzymes. Somatostatin is known to have inhibitory effects on various gastrointestinal functions. Therefore, we determined somatostatin protein production and secretion levels, and biochemical and light microscopical changes following zinc supplementation in the gastrointestinal tract of streptozotocin (STZ)-diabetic rats. The animals were divided into four groups: Group I: control (untreated) animals; Group II: control animals given zinc sulfate; Group III: diabetic animals; and Group IV: diabetic animals given zinc sulfate. Zinc sulfate was given to the animals by gavage at a daily dose of 100 mg/kg body weight for 60 days. Diabetes was induced by intraperitoneal (i.p.) injection of STZ in a single dose of 65 mg/kg. For histological studies, stomach and duodenum tissues were fixed in Bouin solution and sections stained with Masson’s trichrome and Periodic-Acid-Schiff. Tissue homogenates were used for protein, lipid peroxidation (LPO), glutathione (GSH), and nonenzymatic glycosylation (NEG) analyses. Zinc supplementation to the STZ-diabetic rats revealed the protective effect of zinc on these parameters. Zinc supplementation may contribute to prevent at least some complications of diabetes mellitus

  11. Further studies on selective radioprotection by organic zinc salts and synergism of zinc aspartate with WR 2721

    International Nuclear Information System (INIS)

    Floersheim, G.L.; Bieri, A.

    1990-01-01

    Protection of the haematocrit and thrombocytes by small doses of the aminothiol radioprotector WR 2721 was markedly improved by the concomitant administration of small doses of zinc aspartate. Zinc aspartate was the only one of the tested zinc salts not inhibiting the regression induced by radiotherapy of human tumours grown as xenografts in immunosuppressed mice. This also applied to zinc aspartate with WR 2721. A dose of zinc aspartate which afforded synergistic haematological protection did not enhance the toxicity of WR 2721. The synergism of zinc aspartate with WR 2721 and the differential radioprotection of the combined protocol may make it possible in clinical cancer radiotherapy to obtain selective radioprotection at a lower toxicity giving an improved therapeutic ratio compared with WR 2721 alone. (author)

  12. On the r-dynamic chromatic number of the corronation by complete graph

    Science.gov (United States)

    Indah Kristiana, Arika; Imam Utoyo, M.; Dafik

    2018-04-01

    In this paper we will study the r-dynamic chromatic number of the coronation by complete graph. A proper k-coloring of graph G such that the neighbors of any vertex v receive at least min{r, d(v)} different colors. The r-dynamic chromatic number, χ r (G) is the minimum k such that graph G has an r-dynamic k-coloring. We will obtain lower bound of the r-dynamic chromatic number of {χ }r({K}nȯ H), and {χ }r(Hȯ {K}m) We also study the exact value of the r-dynamic chromatic number of {χ }r({K}nȯ {S}m),{χ }r({K}nȯ {F}m),{χ }r({S}nȯ {K}m),{χ }r({F}nȯ {K}m) and {χ }r({K}nȯ {K}m) for m, n > 3.

  13. Accurate and fiducial-marker-free correction for three-dimensional chromatic shift in biological fluorescence microscopy.

    Science.gov (United States)

    Matsuda, Atsushi; Schermelleh, Lothar; Hirano, Yasuhiro; Haraguchi, Tokuko; Hiraoka, Yasushi

    2018-05-15

    Correction of chromatic shift is necessary for precise registration of multicolor fluorescence images of biological specimens. New emerging technologies in fluorescence microscopy with increasing spatial resolution and penetration depth have prompted the need for more accurate methods to correct chromatic aberration. However, the amount of chromatic shift of the region of interest in biological samples often deviates from the theoretical prediction because of unknown dispersion in the biological samples. To measure and correct chromatic shift in biological samples, we developed a quadrisection phase correlation approach to computationally calculate translation, rotation, and magnification from reference images. Furthermore, to account for local chromatic shifts, images are split into smaller elements, for which the phase correlation between channels is measured individually and corrected accordingly. We implemented this method in an easy-to-use open-source software package, called Chromagnon, that is able to correct shifts with a 3D accuracy of approximately 15 nm. Applying this software, we quantified the level of uncertainty in chromatic shift correction, depending on the imaging modality used, and for different existing calibration methods, along with the proposed one. Finally, we provide guidelines to choose the optimal chromatic shift registration method for any given situation.

  14. Separating monocular and binocular neural mechanisms mediating chromatic contextual interactions.

    Science.gov (United States)

    D'Antona, Anthony D; Christiansen, Jens H; Shevell, Steven K

    2014-04-17

    When seen in isolation, a light that varies in chromaticity over time is perceived to oscillate in color. Perception of that same time-varying light may be altered by a surrounding light that is also temporally varying in chromaticity. The neural mechanisms that mediate these contextual interactions are the focus of this article. Observers viewed a central test stimulus that varied in chromaticity over time within a larger surround that also varied in chromaticity at the same temporal frequency. Center and surround were presented either to the same eye (monocular condition) or to opposite eyes (dichoptic condition) at the same frequency (3.125, 6.25, or 9.375 Hz). Relative phase between center and surround modulation was varied. In both the monocular and dichoptic conditions, the perceived modulation depth of the central light depended on the relative phase of the surround. A simple model implementing a linear combination of center and surround modulation fit the measurements well. At the lowest temporal frequency (3.125 Hz), the surround's influence was virtually identical for monocular and dichoptic conditions, suggesting that at this frequency, the surround's influence is mediated primarily by a binocular neural mechanism. At higher frequencies, the surround's influence was greater for the monocular condition than for the dichoptic condition, and this difference increased with temporal frequency. Our findings show that two separate neural mechanisms mediate chromatic contextual interactions: one binocular and dominant at lower temporal frequencies and the other monocular and dominant at higher frequencies (6-10 Hz).

  15. Pupillometer-based objective chromatic perimetry in normal eyes and patients with retinal photoreceptor dystrophies.

    Science.gov (United States)

    Skaat, Alon; Sher, Ifat; Kolker, Andrew; Elyasiv, Sivan; Rosenfeld, Elkana; Mhajna, Mohamad; Melamed, Shlomo; Belkin, Michael; Rotenstreich, Ygal

    2013-04-17

    To evaluate a novel objective perimetry using multifocal chromatic pupil light reflex in normal participants and patients with photoreceptor dysfunction, and to relate this new technique with subjective dark-adapted chromatic Goldmann perimetry. Thirty-two eyes of 17 retinitis pigmentosa (RP) or cone-rod dystrophy patients and 20 eyes of 12 healthy individuals were tested. A computerized infrared video pupillometer was used to record changes in pupil diameter in response to short- and long-wavelength stimuli (peak 485 and 640 nm, respectively; light intensity 40 cd/m(2)) at 13 different points of the 30° visual field (VF), under background illumination of 2.7 cd/m(2). The pupillary response (PR) of patients was compared with PR obtained from normal control participants. In 11 patients, the pupillary responses were also compared with their findings on dark-adapted chromatic Goldmann perimetry. Significantly reduced pupillary responses were obtained in RP patients in response to the short-wavelength stimulus in nearly all perimetric locations (P chromatic Goldmann perimetry. In all patients that were tested by the chromatic Goldmann, minimal PR was recorded in areas that were nondetected in the chromatic Goldmann perimetry. This study demonstrates the potential feasibility of using pupillometer-based chromatic perimetry for objectively assessing VF defects and retinal function in patients with retinal dystrophies. (ClinicalTrials.gov number, NCT01021982.).

  16. Psychophysical and physiological responses to gratings with luminance and chromatic components of different spatial frequencies.

    Science.gov (United States)

    Cooper, Bonnie; Sun, Hao; Lee, Barry B

    2012-02-01

    Gratings that contain luminance and chromatic components of different spatial frequencies were used to study the segregation of signals in luminance and chromatic pathways. Psychophysical detection and discrimination thresholds to these compound gratings, with luminance and chromatic components of the one either half or double the spatial frequency of the other, were measured in human observers. Spatial frequency tuning curves for detection of compound gratings followed the envelope of those for luminance and chromatic gratings. Different grating types were discriminable at detection threshold. Fourier analysis of physiological responses of macaque retinal ganglion cells to compound waveforms showed chromatic information to be restricted to the parvocellular pathway and luminance information to the magnocellular pathway. Taken together, the human psychophysical and macaque physiological data support the strict segregation of luminance and chromatic information in independent channels, with the magnocellular and parvocellular pathways, respectively, serving as likely the physiological substrates. © 2012 Optical Society of America

  17. Uncertainty of chromatic dispersion estimation from transmitted waveforms in direct detection systems

    Science.gov (United States)

    Lach, Zbigniew T.

    2017-08-01

    A possibility is shown of a non-disruptive estimation of chromatic dispersion in a fiber of an intensity modulation communication line under work conditions. Uncertainty of the chromatic dispersion estimates is analyzed and quantified with the use of confidence intervals.

  18. Radiation Induced G2 Chromatic Break and Repairs Kinetics in Human Lymphoblastoid Cells

    International Nuclear Information System (INIS)

    Seong, Jin Sil

    1993-01-01

    In understanding radiosensitivity a new concept of inherent radiosensitivity based on individuality and heterogeneity within a population has recently beer explored. There has been some discussion of possible mechanism underlying differences in radiosensitivity between cells. Ataxia telangiectasia(AT), a rare autosomal recessive genetic disorder, is characterized by hypersensitivity to lonizing radiation and other DNA damaging agents at the cellular level. There have been a lot of efforts to describe the cause of this hypersensitivity to radiation. At the cellular level, chromosome repair kinetics study would be an appropriate approach. The purpose of this study was to better understand radiosensitivity in an approach to investigate kinetics of induction and repair of G2 chromatic breaks using normal, AT heterozygous(ATH), and AT homozygous lymphoblastoid cell lines. In an attempt to estimate initial damage, 9-β-D-arabinosyl-2-fluoroadenine, an inhibitor of DNA synthesis and repair, was used in this study. It was found from this study that radiation induces higher chromatid breaks in AT than in normal and ATH cells. There was no significant differences of initial chromatid breaks between normal and ATH cells. Repair kinetics was the same for all. So the higher level of breaks in AT G2 cells is thought to be a reflection of the increased initial damage. The amount of initial damage correlated well with survival fraction at 2 Gy of cell survival curve following radiation. Therefore, the difference of radiosensitivity in terms of G2 chromosomal sensitivity is thought to result from the difference of initial damage

  19. Cytotoxicant-induced trophoblast dysfunction and abnormal pregnancy outcomes: role of zinc and metallothionein.

    Science.gov (United States)

    McAleer, Mary Frances; Tuan, Rocky S

    2004-12-01

    Normal trophoblast function, including implantation, hormone production, and formation of the selectively permeable maternofetal barrier, is essential for the establishment and maintenance of the fetoplacental unit and proper fetal development. Maternal cytotoxicant exposure causes the destruction of these cells, especially the terminally differentiated syncytiotrophoblasts, and results in a myriad of poor pregnancy outcomes. These outcomes range from intrauterine growth retardation and malformation to spontaneous abortion or stillbirth. There is recent evidence that the metal-binding protein, metallothionein, is involved in the protection of human trophoblastic cells from heavy metal-induced and severe oxidative stress-induced apoptosis. Metallothionein, with its unique biochemical structure, can both bind essential metal ions, such as the transcription modulator zinc, and yet allow their ready displacement by toxic nonessential metal ions or damaging free radicals. These properties suggest that metallothionein may be responsible not only for sequestering the cytotoxic agents, but also for altering signal transduction in the affected cells. Here, we review several identified causes of adverse pregnancy outcomes (specifically, prenatal exposure to cigarette smoke and alcohol, gestational infection, and exposure to environmental contaminants), discuss the role of zinc in modulating the cellular response to these toxic insults, and then propose how metallothionein may function to mediate this protective response. Published 2005 Wiley-Liss, Inc.

  20. Zinc finger protein 598 inhibits cell survival by promoting UV-induced apoptosis.

    Science.gov (United States)

    Yang, Qiaohong; Gupta, Romi

    2018-01-19

    UV is one of the major causes of DNA damage induced apoptosis. However, cancer cells adopt alternative mechanisms to evade UV-induced apoptosis. To identify factors that protect cancer cells from UV-induced apoptosis, we performed a genome wide short-hairpin RNA (shRNA) screen, which identified Zinc finger protein 598 (ZNF598) as a key regulator of UV-induced apoptosis. Here, we show that UV irradiation transcriptionally upregulates ZNF598 expression. Additionally, ZNF598 knockdown in cancer cells inhibited UV-induced apoptosis. In our study, we observe that ELK1 mRNA level as well as phosphorylated ELK1 levels was up regulated upon UV irradiation, which was necessary for UV irradiation induced upregulation of ZNF598. Cells expressing ELK1 shRNA were also resistant to UV-induced apoptosis, and phenocopy ZNF598 knockdown. Upon further investigation, we found that ZNF598 knockdown inhibits UV-induced apoptotic gene expression, which matches with decrease in percentage of annexin V positive cell. Similarly, ectopic expression of ZNF598 promoted apoptotic gene expression and also increased annexin V positive cells. Collectively, these results demonstrate that ZNF598 is a UV irradiation regulated gene and its loss results in resistance to UV-induced apoptosis.

  1. Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity

    Science.gov (United States)

    Lin, Cun; Hara, Ayaka; Comparini, Diego; Bouteau, François; Kawano, Tomonori

    2015-01-01

    Al3+ toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al3+ toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn2+ against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn2+ interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn2+ on Al3+-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn2+-dependent inhibition of the Al3+-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al3+/Zn2+ interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn2+ at physiological concentrations can protect the cells by preventing the Al3+-induced superoxide generation and cell death. Furthermore, the regulation of the Ca2+ signaling, i.e., change in the cytosolic Ca2+ ion concentration, and the cross-talks among the elements which participate in the pathway were further explored. PMID:26648960

  2. Disparate roles of zinc in chemical hypoxia-induced neuronal death

    Directory of Open Access Journals (Sweden)

    Sujeong eKim

    2015-01-01

    Full Text Available Accumulating evidence has provided a causative role of zinc (Zn2+ in neuronal death following ischemic brain injury. Using a hypoxia model of primary cultured cortical neurons with hypoxia-inducing chemicals, cobalt chloride (1 mM CoCl2, deferoxamine (3 mM DFX, and sodium azide (2 mM NaN3, we evaluated whether Zn2+ is involved in hypoxic neuronal death. The hypoxic chemicals rapidly elicited intracellular Zn2+ release/accumulation in viable neurons. The immediate addition of the Zn2+ chelator, CaEDTA or N,N,N’N’-tetrakis-(2-pyridylmethyl ethylenediamine (TPEN, prevented the intracellular Zn2+ load and CoCl2-induced neuronal death, but neither 3-hour-later Zn2+ chelation nor a non-Zn2+ chelator ZnEDTA (1 mM demonstrated any effects. However, neither CaEDTA nor TPEN rescued neurons from cell death following DFX- or NaN3-induced hypoxia, whereas ZnEDTA rendered them resistant to the hypoxic injury. Instead, the immediate supplementation of Zn2+ rescued DFX- and NaN3-induced neuronal death. The iron supplementation also afforded neuroprotection against DFX-induced hypoxic injury. Thus, although intracellular Zn2+ release/accumulation is common during chemical hypoxia, Zn2+ might differently influence the subsequent fate of neurons; it appears to play a neurotoxic or neuroprotective role depending on the hypoxic chemical used. These results also suggest that different hypoxic chemicals may induce neuronal death via distinct mechanisms.

  3. Disparate roles of zinc in chemical hypoxia-induced neuronal death.

    Science.gov (United States)

    Kim, Sujeong; Seo, Jung-Woo; Oh, Shin Bi; Kim, So Hee; Kim, Inki; Suh, Nayoung; Lee, Joo-Yong

    2015-01-01

    Accumulating evidence has provided a causative role of zinc (Zn(2+)) in neuronal death following ischemic brain injury. Using a hypoxia model of primary cultured cortical neurons with hypoxia-inducing chemicals, cobalt chloride (1 mM CoCl2), deferoxamine (3 mM DFX), and sodium azide (2 mM NaN3), we evaluated whether Zn(2+) is involved in hypoxic neuronal death. The hypoxic chemicals rapidly elicited intracellular Zn(2+) release/accumulation in viable neurons. The immediate addition of the Zn(2+) chelator, CaEDTA or N,N,N'N'-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN), prevented the intracellular Zn(2+) load and CoCl2-induced neuronal death, but neither 3 hour later Zn(2+) chelation nor a non-Zn(2+) chelator ZnEDTA (1 mM) demonstrated any effects. However, neither CaEDTA nor TPEN rescued neurons from cell death following DFX- or NaN3-induced hypoxia, whereas ZnEDTA rendered them resistant to the hypoxic injury. Instead, the immediate supplementation of Zn(2+) rescued DFX- and NaN3-induced neuronal death. The iron supplementation also afforded neuroprotection against DFX-induced hypoxic injury. Thus, although intracellular Zn(2+) release/accumulation is common during chemical hypoxia, Zn(2+) might differently influence the subsequent fate of neurons; it appears to play a neurotoxic or neuroprotective role depending on the hypoxic chemical used. These results also suggest that different hypoxic chemicals may induce neuronal death via distinct mechanisms.

  4. Chromatic and achromatic monocular deprivation produce separable changes of eye dominance in adults.

    Science.gov (United States)

    Zhou, Jiawei; Reynaud, Alexandre; Kim, Yeon Jin; Mullen, Kathy T; Hess, Robert F

    2017-11-29

    Temporarily depriving one eye of its input, in whole or in part, results in a transient shift in eye dominance in human adults, with the patched eye becoming stronger and the unpatched eye weaker. However, little is known about the role of colour contrast in these behavioural changes. Here, we first show that the changes in eye dominance and contrast sensitivity induced by monocular eye patching affect colour and achromatic contrast sensitivity equally. We next use dichoptic movies, customized and filtered to stimulate the two eyes differentially. We show that a strong imbalance in achromatic contrast between the eyes, with no colour content, also produces similar, unselective shifts in eye dominance for both colour and achromatic contrast sensitivity. Interestingly, if this achromatic imbalance is paired with similar colour contrast in both eyes, the shift in eye dominance is selective, affecting achromatic but not chromatic contrast sensitivity and revealing a dissociation in eye dominance for colour and achromatic image content. On the other hand, a strong imbalance in chromatic contrast between the eyes, with no achromatic content, produces small, unselective changes in eye dominance, but if paired with similar achromatic contrast in both eyes, no changes occur. We conclude that perceptual changes in eye dominance are strongly driven by interocular imbalances in achromatic contrast, with colour contrast having a significant counter balancing effect. In the short term, eyes can have different dominances for achromatic and chromatic contrast, suggesting separate pathways at the site of these neuroplastic changes. © 2017 The Author(s).

  5. Chromatic dispersion of liquid crystal infiltrated capillary tubes and photonic crystal fibers

    DEFF Research Database (Denmark)

    Rasmussen, Per Dalgaard; Lægsgaard, Jesper; Bang, Ole

    2006-01-01

    We consider chromatic dispersion of capillary tubes and photonic crystal fibers infiltrated with liquid crystals. A perturbative scheme for inclusion of material dispersion of both liquid crystal and the surrounding waveguide material is derived. The method is used to calculate the chromatic...

  6. Cloning and sequence analysis demonstrate the chromate reduction ability of a novel chromate reductase gene from Serratia sp.

    Science.gov (United States)

    Deng, Peng; Tan, Xiaoqing; Wu, Ying; Bai, Qunhua; Jia, Yan; Xiao, Hong

    2015-03-01

    The ChrT gene encodes a chromate reductase enzyme which catalyzes the reduction of Cr(VI). The chromate reductase is also known as flavin mononucleotide (FMN) reductase (FMN_red). The aim of the present study was to clone the full-length ChrT DNA from Serratia sp. CQMUS2 and analyze the deduced amino acid sequence and three-dimensional structure. The putative ChrT gene fragment of Serratia sp. CQMUS2 was isolated by polymerase chain reaction (PCR), according to the known FMN_red gene sequence from Serratia sp. AS13. The flanking sequences of the ChrT gene were obtained by high efficiency TAIL-PCR, while the full-length gene of ChrT was cloned in Escherichia coli for subsequent sequencing. The nucleotide sequence of ChrT was submitted onto GenBank under the accession number, KF211434. Sequence analysis of the gene and amino acids was conducted using the Basic Local Alignment Search Tool, and open reading frame (ORF) analysis was performed using ORF Finder software. The ChrT gene was found to be an ORF of 567 bp that encodes a 188-amino acid enzyme with a calculated molecular weight of 20.4 kDa. In addition, the ChrT protein was hypothesized to be an NADPH-dependent FMN_red and a member of the flavodoxin-2 superfamily. The amino acid sequence of ChrT showed high sequence similarity to the FMN reductase genes of Klebsiella pneumonia and Raoultella ornithinolytica , which belong to the flavodoxin-2 superfamily. Furthermore, ChrT was shown to have a 85.6% similarity to the three-dimensional structure of Escherichia coli ChrR, sharing four common enzyme active sites for chromate reduction. Therefore, ChrT gene cloning and protein structure determination demonstrated the ability of the gene for chromate reduction. The results of the present study provide a basis for further studies on ChrT gene expression and protein function.

  7. Cloning and sequence analysis demonstrate the chromate reduction ability of a novel chromate reductase gene from Serratia sp

    Science.gov (United States)

    DENG, PENG; TAN, XIAOQING; WU, YING; BAI, QUNHUA; JIA, YAN; XIAO, HONG

    2015-01-01

    The ChrT gene encodes a chromate reductase enzyme which catalyzes the reduction of Cr(VI). The chromate reductase is also known as flavin mononucleotide (FMN) reductase (FMN_red). The aim of the present study was to clone the full-length ChrT DNA from Serratia sp. CQMUS2 and analyze the deduced amino acid sequence and three-dimensional structure. The putative ChrT gene fragment of Serratia sp. CQMUS2 was isolated by polymerase chain reaction (PCR), according to the known FMN_red gene sequence from Serratia sp. AS13. The flanking sequences of the ChrT gene were obtained by high efficiency TAIL-PCR, while the full-length gene of ChrT was cloned in Escherichia coli for subsequent sequencing. The nucleotide sequence of ChrT was submitted onto GenBank under the accession number, KF211434. Sequence analysis of the gene and amino acids was conducted using the Basic Local Alignment Search Tool, and open reading frame (ORF) analysis was performed using ORF Finder software. The ChrT gene was found to be an ORF of 567 bp that encodes a 188-amino acid enzyme with a calculated molecular weight of 20.4 kDa. In addition, the ChrT protein was hypothesized to be an NADPH-dependent FMN_red and a member of the flavodoxin-2 superfamily. The amino acid sequence of ChrT showed high sequence similarity to the FMN reductase genes of Klebsiella pneumonia and Raoultella ornithinolytica, which belong to the flavodoxin-2 superfamily. Furthermore, ChrT was shown to have a 85.6% similarity to the three-dimensional structure of Escherichia coli ChrR, sharing four common enzyme active sites for chromate reduction. Therefore, ChrT gene cloning and protein structure determination demonstrated the ability of the gene for chromate reduction. The results of the present study provide a basis for further studies on ChrT gene expression and protein function. PMID:25667630

  8. The Protective Role of Zinc Sulphate on Ethanol -Induced Liver and Kidney Damages in Rats

    International Nuclear Information System (INIS)

    Al-Damegh, Mona Abdalla

    2007-01-01

    Around the world more and more people suffer from alcoholism. Addiction problems, alcoholism and excessive use of drugs both medical and nonmedical, are major causes of liver and kidney damage in adults. The purpose of this study was to investigate on the protective role of zinc sulphate on liver and kidney in rats with acute alcoholism. Wistar albino rats were divided into four groups. Group I; control group, group 2; given only Zinc Sulphate (100 mg/kg/day for 3days), group 3; rats given absolute ethanol (1 ml of absolute ethanol administrated by gavage technique to each rat), group 4 given Zinc sulphate prior to the administration of absolute ethanol. The results of this study revealed that acute ethanol exposure caused degenerative morphological changes in the liver and kidney. Significant difference were found in the levels of serum, liver, kidney super oxide dismutase(SOD), catalase (CAT), nitric oxide(NO), and malondialdehyde (MDA) in the ethanol group compared to the control group. Moreover ,serum urea, creatnine, uric acid, alkaline phoshpatase and transaminases activities (GOTand GPT) were increased in the ethanol group compared to the control group. On the other hand,administration of zinc sulphate in the ethanol group caused a significant decrease in the degenerative changes, lipid peroxidation, antioxidant enzymes, and nitric oxide in serum, liver, and kidney. It can be concluded that zinc Sulphate has a protective role on the ethanol induced liver and kidney injury. In addition ,nitric oxide is involved in the mechanism of acute alcohol intoxication. (author)

  9. Measurement and correction of transverse chromatic offsets for multi-wavelength retinal microscopy in the living eye.

    Science.gov (United States)

    Harmening, Wolf M; Tiruveedhula, Pavan; Roorda, Austin; Sincich, Lawrence C

    2012-09-01

    A special challenge arises when pursuing multi-wavelength imaging of retinal tissue in vivo, because the eye's optics must be used as the main focusing elements, and they introduce significant chromatic dispersion. Here we present an image-based method to measure and correct for the eye's transverse chromatic aberrations rapidly, non-invasively, and with high precision. We validate the technique against hyperacute psychophysical performance and the standard chromatic human eye model. In vivo correction of chromatic dispersion will enable confocal multi-wavelength images of the living retina to be aligned, and allow targeted chromatic stimulation of the photoreceptor mosaic to be performed accurately with sub-cellular resolution.

  10. The effects of luminance contribution from large fields to chromatic visual evoked potentials.

    Science.gov (United States)

    Skiba, Rafal M; Duncan, Chad S; Crognale, Michael A

    2014-02-01

    Though useful from a clinical and practical standpoint uniform, large-field chromatic stimuli are likely to contain luminance contributions from retinal inhomogeneities. Such contribution can significantly influence psychophysical thresholds. However, the degree to which small luminance artifacts influence the chromatic VEP has been debated. In particular, claims have been made that band-pass tuning observed in chromatic VEPs result from luminance intrusion. However, there has been no direct evidence presented to support these claims. Recently, large-field isoluminant stimuli have been developed to control for intrusion from retinal inhomogeneities with particular regard to the influence of macular pigment. We report here the application of an improved version of these full-field stimuli to directly test the influence of luminance intrusion on the temporal tuning of the chromatic VEP. Our results show that band-pass tuning persists even when isoluminance is achieved throughout the extent of the stimulus. In addition, small amounts of luminance intrusion affect neither the shape of the temporal tuning function nor the major components of the VEP. These results support the conclusion that the chromatic VEP can depart substantially from threshold psychophysics with regard to temporal tuning and that obtaining a low-pass function is not requisite evidence of selective chromatic activation in the VEP. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Study of Chromatic parameters of Line, Total, Middle graphs and Graph operators of Bipartite graph

    Science.gov (United States)

    Nagarathinam, R.; Parvathi, N.

    2018-04-01

    Chromatic parameters have been explored on the basis of graph coloring process in which a couple of adjacent nodes receives different colors. But the Grundy and b-coloring executes maximum colors under certain restrictions. In this paper, Chromatic, b-chromatic and Grundy number of some graph operators of bipartite graph has been investigat

  12. Proteomic analysis of chromate response in Staphylococcus ...

    African Journals Online (AJOL)

    user

    2012-04-18

    Apr 18, 2012 ... analysis was performed to identify proteins involved in chromate stress response of Staphylococcus saprophyticus .... Proteins were visualized by PharosFXTM molecular imager and scanner ..... Molecular dynamics of the.

  13. Zinc supplementation induces apoptosis and enhances antitumor efficacy of docetaxel in non-small-cell lung cancer

    Directory of Open Access Journals (Sweden)

    Kocdor H

    2015-07-01

    Full Text Available Hilal Kocdor,1,2 Halil Ates,1 Suleyman Aydin,3 Ruksan Cehreli,1 Firat Soyarat,2 Pinar Kemanli,2 Duygu Harmanci,2 Hakan Cengiz,2 Mehmet Ali Kocdor4 1Institute of Oncology, Dokuz Eylul University, 2Department of Molecular Medicine, Institute of Health Sciences, Dokuz Eylul University, Izmir Turkey; 3Department of Biochemistry, Firat University School of Medicine, Elazig, 4Department of Surgery, School of Medicine, Dokuz Eylul University, Izmir, Turkey Background: Exposure to exogenous zinc results in increased apoptosis, growth inhibition, and altered oxidative stress in cancer cells. Previous studies also suggested that zinc sensitizes some cancer cells to cytotoxic agents depending on the p53 status. Therefore, zinc supplementation may show anticancer efficacy solely and may increase docetaxel-induced cytotoxicity in non-small-cell lung cancer cells.Methods: Here, we report the effects of several concentrations of zinc combined with docetaxel on p53-wild-type (A549 and p53-null (H1299 cells. We evaluated cellular viability, apoptosis, and cell cycle progression as well as oxidative stress parameters, including superoxide dismutase, glutathione peroxidase, and malondialdehyde levels.Results: Zinc reduced the viability of A549 cells and increased the apoptotic response in both cell lines in a dose-dependent manner. Zinc also amplified the docetaxel effects and reduced its inhibitory concentration 50 (IC50 values. The superoxide dismutase levels increased in all treatment groups; however, glutathione peroxidase was slightly increased in the combination treatments. Zinc also caused malondialdehyde elevations at 50 µM and 100 µM.Conclusion: Zinc has anticancer efficacy against non-small-cell lung cancer cells in the presence of functionally active p53 and enhances docetaxel efficacy in both p53-wild-type and p53-deficient cancer cells. Keywords: lung cancer, zinc, docetaxel, A549, H1299

  14. Chromatic polynomials of planar triangulations, the Tutte upper bound and chromatic zeros

    International Nuclear Information System (INIS)

    Shrock, Robert; Xu Yan

    2012-01-01

    Tutte proved that if G pt is a planar triangulation and P(G pt , q) is its chromatic polynomial, then |P(G pt , τ + 1)| ⩽ (τ − 1) n−5 , where τ=(1+√5 )/2 and n is the number of vertices in G pt . Here we study the ratio r(G pt ) = |P(G pt , τ + 1)|/(τ − 1) n−5 for a variety of planar triangulations. We construct infinite recursive families of planar triangulations G pt,m depending on a parameter m linearly related to n and show that if P(G pt,m , q) only involves a single power of a polynomial, then r(G pt,m ) approaches zero exponentially fast as n → ∞. We also construct infinite recursive families for which P(G pt,m , q) is a sum of powers of certain functions and show that for these, r(G pt,m ) may approach a finite nonzero constant as n → ∞. The connection between the Tutte upper bound and the observed chromatic zero(s) near to τ + 1 is investigated. We report the first known graph for which the zero(s) closest to τ + 1 is not real, but instead is a complex-conjugate pair. Finally, we discuss connections with the nonzero ground-state entropy of the Potts antiferromagnet on these families of graphs. (paper)

  15. Chromatic roots and hamiltonian paths

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2000-01-01

    We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result...

  16. Second order chromaticity of the interaction regions in the collider

    International Nuclear Information System (INIS)

    Sen, T.; Syphers, M.J.

    1993-01-01

    The collider in the SSC has large second order chromaticity (ξ 2 ) with the interaction regions (IRs) contributing substantially to it. The authors calculate the general expression for ξ 2 in a storage ring and find that it is driven by the first order chromatic beta wave. Specializing to the interaction regions, they show that ξ 2 is a minimum when the phase advance (Δμ IP -IP) between adjacent interaction points is an odd multiple of π/2 and both IRs are identical. In this case the first order chromatic beta wave is confined within the IRs. Conversely, ξ 2 is large either if δμ IP -IP = (2n + 1)π/2 and the two IRs are very far from equality or if the two IRs are equal but Δμ IP -IP = nπ

  17. Chromatic-free spatially resolved optical emission spectroscopy diagnostics for microplasma

    International Nuclear Information System (INIS)

    Zhu Liguo; Chen Wencong; Zhu Ximing; Pu Yikang; Li Zeren

    2009-01-01

    A chromatic-free spatially resolved diagnostic system for microplasma measurement is proposed and demonstrated, which consists of an optical chromatic-free microscope mirror system, an electron multiplying charge coupled device (EMCCD), and bandpass filters. The diagnostic system free of chromatic aberrations with a spatial resolution of about 6 μm is achieved. The factors that limit the resolution of this diagnostic system have been analyzed, which are optical diffraction, the pixel size of the EMCCD, and the thickness of the microplasma. In this paper, the optimal condition for achieving a maximum resolution power has been analyzed. With this diagnostic system, we revealed the spatial nonuniformity of a microwave atmospheric-pressure argon microplasma. Furthermore, the spatial distribution of the time-averaged effective electron temperature has been estimated from the intensity distributions of 750.4 and 415.8 nm emissions.

  18. Effect of zinc gluconate, sage oil on inflammatory patterns and hyperglycemia in zinc deficient diabetic rats.

    Science.gov (United States)

    Elseweidy, Mohamed M; Ali, Abdel-Moniem A; Elabidine, Nabila Zein; Mursey, Nada M

    2017-11-01

    The relationship between zinc homeostasis and pancreatic function had been established. In this study we aimed firstly to configure the inflammatory pattern and hyperglycemia in zinc deficient diabetic rats. Secondly to illustrate the effect of two selected agents namely Zinc gluconate and sage oil (Salvia Officinalis, family Lamiaceae). Rats were fed on Zinc deficient diet, deionized water for 28days along with Zinc level check up at intervals to achieve zinc deficient state then rats were rendered diabetic through receiving one dose of alloxan monohydrate (120mg/kg) body weight, classified later into 5 subgroups. Treatment with sage oil (0.042mg/kg IP) and Zinc gluconate orally (150mg/kg) body weight daily for 8 weeks significantly reduced serum glucose, C-reactive protein (CRP), Tumor necrosis factor alpha (TNF- α), interleukins-6 1 β, inflammatory8 (IFN ȣ), pancreatic 1L1-β along with an increase in serum Zinc and pancreatic Zinc transporter 8 (ZNT8). Histopathological results of pancreatic tissues showed a good correlation with the biochemical findings. Both sage oil and zinc gluconate induced an improvement in the glycemic and inflammatory states. This may be of value like the therapeutic agent for diabetes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Chromate Reduction in Serratia marcescens Isolated from Tannery Effluent and Potential Application for Bioremediation of Chromate Pollution

    Directory of Open Access Journals (Sweden)

    M.A. Mondaca

    2002-01-01

    Full Text Available Pollution of aquatic systems by heavy metals has resulted in increasing environmental concern because they cannot be biodegraded. One metal that gives reason for concern due to its toxicity is chromium. Cr(VI and Cr(III are the principal forms of chromium found in natural waters. A chromate-resistant strain of the bacterium S. marcescens was isolated from tannery effluent. The strain was able to reduce Cr(VI to Cr(III, and about 80% of chromate was removed from the medium. The reduction seems to occur on the cell surface. Transmission electron microscopic examination of cells revealed that particles were deposited on the outside of bacterial cells. A stable biofilm was formed in less than 10 h, reaching around 1010 cfu attached per milligram of activated carbon. These findings demonstrate that immobilized S. marcescens might be used in industrial waste treatment processes.

  20. V1 mechanisms underlying chromatic contrast detection

    Science.gov (United States)

    Hass, Charles A.

    2013-01-01

    To elucidate the cortical mechanisms of color vision, we recorded from individual primary visual cortex (V1) neurons in macaque monkeys performing a chromatic detection task. Roughly 30% of the neurons that we encountered were unresponsive at the monkeys' psychophysical detection threshold (PT). The other 70% were responsive at threshold but on average, were slightly less sensitive than the monkey. For these neurons, the relationship between neurometric threshold (NT) and PT was consistent across the four isoluminant color directions tested. A corollary of this result is that NTs were roughly four times lower for stimuli that modulated the long- and middle-wavelength sensitive cones out of phase. Nearly one-half of the neurons that responded to chromatic stimuli at the monkeys' detection threshold also responded to high-contrast luminance modulations, suggesting a role for neurons that are jointly tuned to color and luminance in chromatic detection. Analysis of neuronal contrast-response functions and signal-to-noise ratios yielded no evidence for a special set of “cardinal color directions,” for which V1 neurons are particularly sensitive. We conclude that at detection threshold—as shown previously with high-contrast stimuli—V1 neurons are tuned for a diverse set of color directions and do not segregate naturally into red–green and blue–yellow categories. PMID:23446689

  1. Effect of zinc treatment on intestinal motility in experimentally ...

    African Journals Online (AJOL)

    Effect of zinc treatment on intestinal motility in experimentally induced diarrhea in rats. ... Zinc supplementation is a critical new intervention for treating diarrheal episodes in children. Recent studies suggest that administration of zinc along with new low osmolarity oral rehydration solutions / salts (ORS) can reduce the ...

  2. Structure determination and functional analysis of a chromate reductase from Gluconacetobacter hansenii.

    Directory of Open Access Journals (Sweden)

    Hongjun Jin

    Full Text Available Environmental protection through biological mechanisms that aid in the reductive immobilization of toxic metals (e.g., chromate and uranyl has been identified to involve specific NADH-dependent flavoproteins that promote cell viability. To understand the enzyme mechanisms responsible for metal reduction, the enzyme kinetics of a putative chromate reductase from Gluconacetobacter hansenii (Gh-ChrR was measured and the crystal structure of the protein determined at 2.25 Å resolution. Gh-ChrR catalyzes the NADH-dependent reduction of chromate, ferricyanide, and uranyl anions under aerobic conditions. Kinetic measurements indicate that NADH acts as a substrate inhibitor; catalysis requires chromate binding prior to NADH association. The crystal structure of Gh-ChrR shows the protein is a homotetramer with one bound flavin mononucleotide (FMN per subunit. A bound anion is visualized proximal to the FMN at the interface between adjacent subunits within a cationic pocket, which is positioned at an optimal distance for hydride transfer. Site-directed substitutions of residues proposed to involve in both NADH and metal anion binding (N85A or R101A result in 90-95% reductions in enzyme efficiencies for NADH-dependent chromate reduction. In comparison site-directed substitution of a residue (S118A participating in the coordination of FMN in the active site results in only modest (50% reductions in catalytic efficiencies, consistent with the presence of a multitude of side chains that position the FMN in the active site. The proposed proximity relationships between metal anion binding site and enzyme cofactors is discussed in terms of rational design principles for the use of enzymes in chromate and uranyl bioremediation.

  3. Newborns' Discrimination of Chromatic from Achromatic Stimuli.

    Science.gov (United States)

    Adams, Russell J.; And Others

    1986-01-01

    Two experiments assessed the extent of newborns' ability to discriminate color. Results imply that newborns have some, albeit limited, capacity to discriminate chromatic from achromatic stimuli, and hence, are at least dichromats. (Author/DR)

  4. Zinc, nitrogen and salinity interaction on agronomic traits and some ...

    African Journals Online (AJOL)

    use

    2011-11-23

    Nov 23, 2011 ... percentage decreased due to nitrogen, zinc and salinity in the first year but .... Analysis of variance on canola traits affected by nitrogen, zinc and salinity at ...... a result less of the latter are available for fat synthesis ... Na+ and Cl- in plant tissues, effects of nitrogen and zinc ... Zinc alleviates cadmium-induced.

  5. Chromatic aberration correction: an enhancement to the calibration of low-cost digital dermoscopes.

    Science.gov (United States)

    Wighton, Paul; Lee, Tim K; Lui, Harvey; McLean, David; Atkins, M Stella

    2011-08-01

    We present a method for calibrating low-cost digital dermoscopes that corrects for color and inconsistent lighting and also corrects for chromatic aberration. Chromatic aberration is a form of radial distortion that often occurs in inexpensive digital dermoscopes and creates red and blue halo-like effects on edges. Being radial in nature, distortions due to chromatic aberration are not constant across the image, but rather vary in both magnitude and direction. As a result, distortions are not only visually distracting but could also mislead automated characterization techniques. Two low-cost dermoscopes, based on different consumer-grade cameras, were tested. Color is corrected by imaging a reference and applying singular value decomposition to determine the transformation required to ensure accurate color reproduction. Lighting is corrected by imaging a uniform surface and creating lighting correction maps. Chromatic aberration is corrected using a second-order radial distortion model. Our results for color and lighting calibration are consistent with previously published results, while distortions due to chromatic aberration can be reduced by 42-47% in the two systems considered. The disadvantages of inexpensive dermoscopy can be quickly substantially mitigated with a suitable calibration procedure. © 2011 John Wiley & Sons A/S.

  6. Zinc in Infection and Inflammation.

    Science.gov (United States)

    Gammoh, Nour Zahi; Rink, Lothar

    2017-06-17

    Micronutrient homeostasis is a key factor in maintaining a healthy immune system. Zinc is an essential micronutrient that is involved in the regulation of the innate and adaptive immune responses. The main cause of zinc deficiency is malnutrition. Zinc deficiency leads to cell-mediated immune dysfunctions among other manifestations. Consequently, such dysfunctions lead to a worse outcome in the response towards bacterial infection and sepsis. For instance, zinc is an essential component of the pathogen-eliminating signal transduction pathways leading to neutrophil extracellular traps (NET) formation, as well as inducing cell-mediated immunity over humoral immunity by regulating specific factors of differentiation. Additionally, zinc deficiency plays a role in inflammation, mainly elevating inflammatory response as well as damage to host tissue. Zinc is involved in the modulation of the proinflammatory response by targeting Nuclear Factor Kappa B (NF-κB), a transcription factor that is the master regulator of proinflammatory responses. It is also involved in controlling oxidative stress and regulating inflammatory cytokines. Zinc plays an intricate function during an immune response and its homeostasis is critical for sustaining proper immune function. This review will summarize the latest findings concerning the role of this micronutrient during the course of infections and inflammatory response and how the immune system modulates zinc depending on different stimuli.

  7. Quantum-chemical study of the geometric and electronic structure of the chromate anion CrO42- and a chromate group on the surface of finely divided silica by the CNDO/2 method

    International Nuclear Information System (INIS)

    Plyuto, I.V.; Shpak, A.P.; Plyuto, Yu.V.; Chuiko, A.A.

    1989-01-01

    A comparative study of the geometric and electronic structure of the chromate anion CrO 4 2- and a chromate group on the surface of finely divided silica (≡Si-O) 2 - CrO 2 , which was simulated by a CrO 9 Si 6 H 12 cluster, has been carried out by the SCF-MO-LCAO method in the all-valence-electron CNDO/2 approximation. The data obtained on the equilibrium geometry of the chromate group attest to the formation of a double bond between the Cr atom and each O atom (which is not bonded to Si). It has been shown that the support has a significant stabilizing in fluence on the energy of the MO's of the chromate group. The chromate group on an SiO 2 surface is characterized by partial delocalization of the frontier MO's among the skeletal bonds; however, the dominant contribution to the HOMO is made by the 2p AO of the oxygen atoms in the coordination shell of the Cr atom (∼70%), and the dominant contribution to the LUMO is made by the 3d AO of the chromium atom (∼50%). The positions and composition of the lowest unoccupied molecular orbitals point out the possibility of the display of electron-acceptor properties by a chromate group of an SiO 2 surface

  8. Corrosion of chromatic conversion coatings on Aluminium Alloys in electrical and electronic equipment

    International Nuclear Information System (INIS)

    Razavi, R.Sh.; Shahrabi, T.; Mozafarnia, R.

    2002-01-01

    Chromate conversion coating is applied on aluminum 6061. The optimum conditions for chromate bath composition and immersion time are also obtained for standard requirements provision such as corrosion resistance in salt spray test, electrical resistance and coating quality. The applied coatings are electrochemically tested in sea and distilled water. According to Tafel and cyclic polarization curves, the protection mechanism are evaluated in said environments. This evaluation has shown the formation of passive film layer, contains chromate and alumina on the base. The proper behavior of corrosion and electrical conductivity is probably due to this mechanism

  9. Segmentation of color images by chromaticity features using self-organizing maps

    Directory of Open Access Journals (Sweden)

    Farid García-Lamont

    2016-05-01

    Full Text Available Usually, the segmentation of color images is performed using cluster-based methods and the RGB space to represent the colors. The drawback with these methods is the a priori knowledge of the number of groups, or colors, in the image; besides, the RGB space issensitive to the intensity of the colors. Humans can identify different sections within a scene by the chromaticity of its colors of, as this is the feature humans employ to tell them apart. In this paper, we propose to emulate the human perception of color by training a self-organizing map (SOM with samples of chromaticity of different colors. The image to process is mapped to the HSV space because in this space the chromaticity is decoupled from the intensity, while in the RGB space this is not possible. Our proposal does not require knowing a priori the number of colors within a scene, and non-uniform illumination does not significantly affect the image segmentation. We present experimental results using some images from the Berkeley segmentation database by employing SOMs with different sizes, which are segmented successfully using only chromaticity features.

  10. Marginal dietary zinc deprivation augments sepsis-induced alterations in skeletal muscle TNF-α but not protein synthesis.

    Science.gov (United States)

    Crowell, Kristen T; Kelleher, Shannon L; Soybel, David I; Lang, Charles H

    2016-11-01

    Severe zinc deficiency is associated with an increased systemic inflammatory response and mortality after sepsis. However, the impact of mild zinc deficiency, which is more common in populations with chronic illnesses and sepsis, is unknown. In this study, we hypothesized that marginal dietary Zn deprivation (ZM) would amplify tissue inflammation and exacerbate the sepsis-induced decrease in muscle protein synthesis. Adult male C57BL/6 mice were fed a zinc-adequate (ZA) or ZM diet (30 or 10 mg Zn/kg, respectively) over 4 weeks, peritonitis was induced by cecal ligation and puncture (CLP), and mice were examined at either 24 h (acute) or 5 days (chronic) post-CLP Acute sepsis decreased the in vivo rate of skeletal muscle protein synthesis and the phosphorylation of the mTOR substrate 4E-BP1. Acutely, sepsis increased TNF-α and IL-6 mRNA in muscle, and the increase in TNF-α was significantly greater in ZM mice. However, muscle protein synthesis and 4E-BP1 phosphorylation returned to baseline 5 days post-CLP in both ZA and ZM mice. Protein degradation via markers of the ubiquitin proteasome pathway was increased in acute sepsis, yet only MuRF1 mRNA was increased in chronic sepsis and ZM amplified this elevation. Our data suggest that mild zinc deficiency increases TNF-α in muscle acutely after sepsis but does not significantly modulate the rate of muscle protein synthesis. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  11. Spectral discrimination in color blind animals via chromatic aberration and pupil shape.

    Science.gov (United States)

    Stubbs, Alexander L; Stubbs, Christopher W

    2016-07-19

    We present a mechanism by which organisms with only a single photoreceptor, which have a monochromatic view of the world, can achieve color discrimination. An off-axis pupil and the principle of chromatic aberration (where different wavelengths come to focus at different distances behind a lens) can combine to provide "color-blind" animals with a way to distinguish colors. As a specific example, we constructed a computer model of the visual system of cephalopods (octopus, squid, and cuttlefish) that have a single unfiltered photoreceptor type. We compute a quantitative image quality budget for this visual system and show how chromatic blurring dominates the visual acuity in these animals in shallow water. We quantitatively show, through numerical simulations, how chromatic aberration can be exploited to obtain spectral information, especially through nonaxial pupils that are characteristic of coleoid cephalopods. We have also assessed the inherent ambiguity between range and color that is a consequence of the chromatic variation of best focus with wavelength. This proposed mechanism is consistent with the extensive suite of visual/behavioral and physiological data that has been obtained from cephalopod studies and offers a possible solution to the apparent paradox of vivid chromatic behaviors in color blind animals. Moreover, this proposed mechanism has potential applicability in organisms with limited photoreceptor complements, such as spiders and dolphins.

  12. Identification of autophagy genes participating in zinc-induced necrotic cell death in Saccharomyces cerevisiae.

    Science.gov (United States)

    Dziedzic, Slawomir A; Caplan, Allan B

    2011-05-01

    Eukaryotes use a common set of genes to perform two mechanistically similar autophagic processes. Bulk autophagy harvests proteins nonselectively and reuses their constitutents when nutrients are scarce. In contrast, different forms of selective autophagy target protein aggregates or damaged organelles that threaten to interfere with growth. Yeast uses one form of selective autophagy, called cytoplasm-to-vacuole targeting (Cvt), to engulf two vacuolar enzymes in Cvt vesicles ("CVT-somes") within which they are transported to vacuoles for maturation. While both are dispensable normally, bulk and selective autophagy help sustain life under stressful conditions. Consistent with this view, knocking out several genes participating in Cvt and specialized autophagic pathways heightened the sensitivity of Saccharomyces cerevisiae to inhibitory levels of Zn(2+). The loss of other autophagic genes, and genes responsible for apoptotic cell death, had no such effect. Unexpectedly, the loss of members of a third set of autophagy genes heightened cellular resistance to zinc as if they encoded proteins that actively contributed to zinc-induced cell death. Further studies showed that both sensitive and resistant strains accumulated similar amounts of H2O2 during zinc treatments, but that more sensitive strains showed signs of necrosis sooner. Although zinc lethality depended on autophagic proteins, studies with several reporter genes failed to reveal increased autophagic activity. In fact, microscopy analysis indicated that Zn(2+) partially inhibited fusion of Cvt vesicles with vacuoles. Further studies into how the loss of autophagic processes suppressed necrosis in yeast might reveal whether a similar process could occur in plants and animals.

  13. Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes.

    Science.gov (United States)

    Zhai, Yi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; He, Yuanqing; Chang, Shengjiang

    2014-01-01

    An achromatic element eliminating only longitudinal chromatic aberration (LCA) while maintaining transverse chromatic aberration (TCA) is established for the eye model, which involves the angle formed by the visual and optical axis. To investigate the impacts of higher-order aberrations on vision, the actual data of higher-order aberrations of human eyes with three typical levels are introduced into the eye model along visual axis. Moreover, three kinds of individual eye models are established to investigate the impacts of higher-order aberrations, chromatic aberration (LCA+TCA), LCA and TCA on vision under the photopic condition, respectively. Results show that for most human eyes, the impact of chromatic aberration on vision is much stronger than that of higher-order aberrations, and the impact of LCA in chromatic aberration dominates. The impact of TCA is approximately equal to that of normal level higher-order aberrations and it can be ignored when LCA exists.

  14. Strong oriented chromatic number of planar graphs without short cycles

    Directory of Open Access Journals (Sweden)

    Mickaël Montassier

    2008-01-01

    Full Text Available Let M be an additive abelian group. A strong oriented coloringof an oriented graph G is a mapping φ from V(G to M such that (1 φ(u ≠ φ(v whenever uv is an arc in G and (2 φ(v - φ(u ≠ -(φ(t - φ(z whenever uv and zt are two arcs in G. We say that G has a M-strong-oriented coloring. The strong oriented chromatic number of an oriented graph, denoted by χ s (G, is the minimal order of a group M, such that G has M-strong-oriented coloring. This notion was introduced by Nešetřil and Raspaud. In this paper, we pose the following problem: Let i ≥ 4 be an integer. Let G be an oriented planar graph without cycles of lengths 4 to i. Which is the strong oriented chromatic number of G ? Our aim is to determine the impact of triangles on the strong oriented coloring. We give some hints of answers to this problem by proving that: (1 the strong oriented chromatic number of any oriented planar graph without cycles of lengths 4 to 12 is at most 7, and (2 the strong oriented chromatic number of any oriented planar graph without cycles of length 4 or 6 is at most 19.

  15. Neuronal Mechanism for Compensation of Longitudinal Chromatic Aberration-Derived Algorithm.

    Science.gov (United States)

    Barkan, Yuval; Spitzer, Hedva

    2018-01-01

    The human visual system faces many challenges, among them the need to overcome the imperfections of its optics, which degrade the retinal image. One of the most dominant limitations is longitudinal chromatic aberration (LCA), which causes short wavelengths (blue light) to be focused in front of the retina with consequent blurring of the retinal chromatic image. The perceived visual appearance, however, does not display such chromatic distortions. The intriguing question, therefore, is how the perceived visual appearance of a sharp and clear chromatic image is achieved despite the imperfections of the ocular optics. To address this issue, we propose a neural mechanism and computational model, based on the unique properties of the S -cone pathway. The model suggests that the visual system overcomes LCA through two known properties of the S channel: (1) omitting the contribution of the S channel from the high-spatial resolution pathway (utilizing only the L and M channels). (b) Having large and coextensive receptive fields that correspond to the small bistratified cells. Here, we use computational simulations of our model on real images to show how integrating these two basic principles can provide a significant compensation for LCA. Further support for the proposed neuronal mechanism is given by the ability of the model to predict an enigmatic visual phenomenon of large color shifts as part of the assimilation effect.

  16. Performance Comparison of Steam-Based and Chromate Conversion Coatings on Aluminum Alloy 6060

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    In this study, oxide layers generated on aluminum alloy 6060(UNS A96060) using a steam-based process were compared with conventional chromate and chromate-phosphate conversion coatings. Chemical composition and microstructure of the conversion coatings were investigated and their corrosion perfor...

  17. Photon Sieve Bandwidth Broadening by Reduction of Chromatic Aberration Effects Using Second-Stage Diffractive Optics

    Science.gov (United States)

    2015-03-26

    to copyright protection in the United States. AFIT-ENP-MS-15-M-086 PHOTON SIEVE BANDWIDTH BROADENING BY REDUCTION OF CHROMATIC ABERRATION...RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENP-MS-15-M-086 PHOTON SIEVE BANDWIDTH BROADENING BY REDUCTION OF CHROMATIC ABERRATION EFFECTS USING...A photon sieve is a lightweight diffractive optic which can be useful for space- based imaging applications. It is limited by chromatic

  18. Characterization of the main error sources of chromatic confocal probes for dimensional measurement

    International Nuclear Information System (INIS)

    Nouira, H; El-Hayek, N; Yuan, X; Anwer, N

    2014-01-01

    Chromatic confocal probes are increasingly used in high-precision dimensional metrology applications such as roughness, form, thickness and surface profile measurements; however, their measurement behaviour is not well understood and must be characterized at a nanometre level. This paper provides a calibration bench for the characterization of two chromatic confocal probes of 20 and 350 µm travel ranges. The metrology loop that includes the chromatic confocal probe is stable and enables measurement repeatability at the nanometer level. With the proposed system, the major error sources, such as the relative axial and radial motions of the probe with respect to the sample, the material, colour and roughness of the measured sample, the relative deviation/tilt of the probe and the scanning speed are identified. Experimental test results show that the chromatic confocal probes are sensitive to these errors and that their measurement behaviour is highly dependent on them. (paper)

  19. Luminance and chromatic contributions to a hyperacuity task: isolation by contrast polarity and target separation.

    Science.gov (United States)

    Sun, Hao; Cooper, Bonnie; Lee, Barry B

    2012-03-01

    Vernier thresholds are known to be elevated when a target pair has opposite contrast polarity. Polarity reversal is used to assess the role of luminance and chromatic pathways in hyperacuity performance. Psychophysical hyperacuity thresholds were measured for pairs of gratings of various combinations of luminance (Lum) and chromatic (Chr) contrast polarities, at different ratios of luminance to chromatic contrast. With two red-green gratings of matched luminance and chromatic polarity (+Lum+Chr), there was an elevation of threshold at isoluminance. When both luminance and chromatic polarity were mismatched (-Lum-Chr), thresholds were substantially elevated under all conditions. With the same luminance contrast polarity and opposite chromatic polarity (+Lum-Chr) thresholds were only elevated close to isoluminance; in the reverse condition (-Lum+Chr), thresholds were elevated as in the -Lum-Chr condition except close to equiluminance. Similar data were obtained for gratings isolating the short-wavelength cone mechanism. Further psychophysical measurements assessed the role of target separation with matched or mismatched contrast polarity; similar results were found for luminance and chromatic gratings. Comparison physiological data were collected from parafoveal ganglion cells of the macaque retina. Positional precision of ganglion cell signals was assessed under conditions related to the psychophysical measurements. On the basis of these combined observations, it is argued that both magnocellular, parvocellular, and koniocellular pathways have access to cortical positional mechanisms associated with vernier acuity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Reversible Chromatic Response of Polydiacetylene Derivative Vesicles in D2O Solvent.

    Science.gov (United States)

    Shin, Min Jae; Kim, Jong-Duk

    2016-01-26

    The thermal chromatic sensitivity of polydiacetylenes (PDAs) with 10,12-pentacosadiynoic acid (PCDA) derivatives, which have a hydroxyl group (HEEPCDA) and an amine group (APPCDA), were investigated using D2O and H2O as solvents. The vesicle solution with polymerized HEEPCDA exhibited a reversible chromatic response during the heating and cooling cycle in D2O, but not in H2O. On the other hand, the vesicle solution with the polymerized APPCDA exhibited a reversible chromatic response in H2O during the heating and cooling cycle, but the color of the solution did not change much in D2O. The critical vesicle concentration of HEEPCDA was lower in D2O than in H2O, and the chromatic sensitivity of the polymerized vesicles to temperature was slower in D2O than in H2O. We think that it is due to D2O being a more highly structured solvent than H2O with the hydrogen bonding in D2O stronger than that in H2O.

  1. Chromatic Dispersion Estimation in Digital Coherent Receivers

    DEFF Research Database (Denmark)

    Soriano, Ruben Andres; Hauske, Fabian N.; Guerrero Gonzalez, Neil

    2011-01-01

    Polarization-diverse coherent demodulation allows to compensate large values of accumulated linear distortion by digital signal processing. In particular, in uncompensated links without optical dispersion compensation, the parameter of the residual chromatic dispersion (CD) is vital to set...

  2. Fast online simultaneous monitoring of PMD and chromatic dispersion with reduced polarization dependent gain

    Science.gov (United States)

    Ning, G.; Shum, P.; Aditya, S.; Gong, Yandong

    2006-09-01

    We use the expression relating the output state of polarization and PMD vector. Based on this expression we get the power fading including first-order PMD and chromatic dispersion, which is dependent on the angle of precession of output state of polarization around the PMD vector. From the expression for power fading, we get the average power penalty for chromatic dispersion and PMD. We propose a novel and fast PMD and chromatic dispersion monitoring technology. Measured results agree well with theoretical analysis.

  3. Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains

    International Nuclear Information System (INIS)

    Vallee, B.L.; Auld, D.S.; Coleman, J.E.

    1991-01-01

    The authors recognize three distinct motifs of DNA-binding zinc proteins: (i) zinc fingers, (ii) zinc clusters, and (iii) zinc twists. Until very recently, x-ray crystallographic or NMR three-dimensional structure analyses of DNA-binding zinc proteins have not been available to serve as standards of reference for the zinc binding sites of these families of proteins. Those of the DNA-binding domains of the fungal transcription factor GAL4 and the rat glucocorticoid receptor are the first to have been determined. Both proteins contain two zinc binding sites, and in both, cysteine residues are the sole zinc ligands. In GAL4, two zinc atoms are bound to six cysteine residues which form a zinc cluster akin to that of metallothionein; the distance between the two zinc atoms of GAL4 is ∼3.5 angstrom. In the glucocorticoid receptor, each zinc atom is bound to four cysteine residues; the interatomic zinc-zinc distance is ∼13 angstrom, and in this instance, a zinc twist is represented by a helical DNA recognition site located between the two zinc atoms. Zinc clusters and zinc twists are here recognized as two distinctive motifs in DNA-binding proteins containing multiple zinc atoms. For native zinc fingers, structural data do not exist as yet; consequently, the interatomic distances between zinc atoms are not known. As further structural data become available, the structural and functional significance of these different motifs in their binding to DNA and other proteins participating in the transmission of the genetic message will become apparent

  4. Chromatic Roots and Limits of Dense Graphs

    Czech Academy of Sciences Publication Activity Database

    Csikvári, P.; Frenkel, E.; Hladký, Jan; Hubai, T.

    2017-01-01

    Roč. 340, č. 5 (2017), s. 1129-1135 ISSN 0012-365X Institutional support: RVO:67985807 Keywords : chromatic root * graph limit * holomorphic moment Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.639, year: 2016

  5. Zinc treatment ameliorates diarrhea and intestinal inflammation in undernourished rats.

    Science.gov (United States)

    de Queiroz, Camila A A; Fonseca, Said Gonçalves C; Frota, Priscila B; Figueiredo, Italo L; Aragão, Karoline S; Magalhães, Carlos Emanuel C; de Carvalho, Cibele B M; Lima, Aldo Ângelo M; Ribeiro, Ronaldo A; Guerrant, Richard L; Moore, Sean R; Oriá, Reinaldo B

    2014-08-05

    WHO guidelines recommend zinc supplementation as a key adjunct therapy for childhood diarrhea in developing countries, however zinc's anti-diarrheal effects remain only partially understood. Recently, it has been recognized that low-grade inflammation may influence stunting. In this study, we examined whether oral zinc supplementation could improve weight, intestinal inflammation, and diarrhea in undernourished weanling rats. Rats were undernourished using a northeastern Brazil regional diet (RBD) for two weeks, followed by oral gavage with a saturated lactose solution (30 g/kg) in the last 7 days to induce osmotic diarrhea. Animals were checked for diarrhea daily after lactose intake. Blood was drawn in order to measure serum zinc levels by atomic absorption spectroscopy. Rats were euthanized to harvest jejunal tissue for histology and cytokine profiles by ELISA. In a subset of animals, spleen samples were harvested under aseptic conditions to quantify bacterial translocation. Oral zinc supplementation increased serum zinc levels following lactose-induced osmotic diarrhea. In undernourished rats, zinc improved weight gain following osmotic diarrhea and significantly reduced diarrheal scores by the third day of lactose intake (p diarrhea and undernutrition and support the use of zinc to prevent the vicious cycle of malnutrition and diarrhea.

  6. Replacement of corrosion protection chromate primers and paints used in cryogenic applications on the Space Shuttle with wire arc sprayed aluminum coatings

    Science.gov (United States)

    Daniel, R. L.; Sanders, H. L.; Zimmerman, F. R.

    1995-01-01

    With the advent of new environmental laws restricting volatile organic compounds and hexavalent chrome emissions, 'environmentally safe' thermal spray coatings are being developed to replace the traditional corrosion protection chromate primers. A wire arc sprayed aluminum coating is being developed for corrosion protection of low pressure liquid hydrogen carrying ducts on the Space Shuttle Main Engine. Currently, this hardware utilizes a chromate primer to provide protection against corrosion pitting and stress corrosion cracking induced by the cryogenic operating environment. The wire are sprayed aluminum coating has been found to have good potential to provide corrosion protection for flight hardware in cryogenic applications. The coating development, adhesion test, corrosion test and cryogenic flexibility test results will be presented.

  7. Zinc in Infection and Inflammation

    Directory of Open Access Journals (Sweden)

    Nour Zahi Gammoh

    2017-06-01

    Full Text Available Micronutrient homeostasis is a key factor in maintaining a healthy immune system. Zinc is an essential micronutrient that is involved in the regulation of the innate and adaptive immune responses. The main cause of zinc deficiency is malnutrition. Zinc deficiency leads to cell-mediated immune dysfunctions among other manifestations. Consequently, such dysfunctions lead to a worse outcome in the response towards bacterial infection and sepsis. For instance, zinc is an essential component of the pathogen-eliminating signal transduction pathways leading to neutrophil extracellular traps (NET formation, as well as inducing cell-mediated immunity over humoral immunity by regulating specific factors of differentiation. Additionally, zinc deficiency plays a role in inflammation, mainly elevating inflammatory response as well as damage to host tissue. Zinc is involved in the modulation of the proinflammatory response by targeting Nuclear Factor Kappa B (NF-κB, a transcription factor that is the master regulator of proinflammatory responses. It is also involved in controlling oxidative stress and regulating inflammatory cytokines. Zinc plays an intricate function during an immune response and its homeostasis is critical for sustaining proper immune function. This review will summarize the latest findings concerning the role of this micronutrient during the course of infections and inflammatory response and how the immune system modulates zinc depending on different stimuli.

  8. Mixing of Chromatic and Luminance Retinal Signals in Primate Area V1.

    Science.gov (United States)

    Li, Xiaobing; Chen, Yao; Lashgari, Reza; Bereshpolova, Yulia; Swadlow, Harvey A; Lee, Barry B; Alonso, Jose Manuel

    2015-07-01

    Vision emerges from activation of chromatic and achromatic retinal channels whose interaction in visual cortex is still poorly understood. To investigate this interaction, we recorded neuronal activity from retinal ganglion cells and V1 cortical cells in macaques and measured their visual responses to grating stimuli that had either luminance contrast (luminance grating), chromatic contrast (chromatic grating), or a combination of the two (compound grating). As with parvocellular or koniocellular retinal ganglion cells, some V1 cells responded mostly to the chromatic contrast of the compound grating. As with magnocellular retinal ganglion cells, other V1 cells responded mostly to the luminance contrast and generated a frequency-doubled response to equiluminant chromatic gratings. Unlike magnocellular and parvocellular retinal ganglion cells, V1 cells formed a unimodal distribution for luminance/color preference with a 2- to 4-fold bias toward luminance. V1 cells associated with positive local field potentials in deep layers showed the strongest combined responses to color and luminance and, as a population, V1 cells encoded a diverse combination of luminance/color edges that matched edge distributions of natural scenes. Taken together, these results suggest that the primary visual cortex combines magnocellular and parvocellular retinal inputs to increase cortical receptive field diversity and to optimize visual processing of our natural environment. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Photographic simulation of off-axis blurring due to chromatic aberration in spectacle lenses.

    Science.gov (United States)

    Doroslovački, Pavle; Guyton, David L

    2015-02-01

    Spectacle lens materials of high refractive index (nd) tend to have high chromatic dispersion (low Abbé number [V]), which may contribute to visual blurring with oblique viewing. A patient who noted off-axis blurring with new high-refractive-index spectacle lenses prompted us to do a photographic simulation of the off-axis aberrations in 3 readily available spectacle lens materials, CR-39 (nd = 1.50), polyurethane (nd = 1.60), and polycarbonate (nd = 1.59). Both chromatic and monochromatic aberrations were found to cause off-axis image degradation. Chromatic aberration was more prominent in the higher-index materials (especially polycarbonate), whereas the lower-index CR-39 had more astigmatism of oblique incidence. It is important to consider off-axis aberrations when a patient complains of otherwise unexplained blurred vision with a new pair of spectacle lenses, especially given the increasing promotion of high-refractive-index materials with high chromatic dispersion. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  10. Implementation of fluidized granulated iron reactors in a chromate remediation process

    International Nuclear Information System (INIS)

    Müller, P.; Lorber, K.E.; Mischitz, R.; Weiß, C.

    2014-01-01

    A new approach concerning in-situ remediation on source (‘hot-spot’) decontamination of a chromate damage in connection with an innovative pump-and-treat-technique has been developed. Iron granulates show significant higher reduction rates, using fluidized bed conditions, than a literature study with a fixed bed installation of small-sized iron granules. First results from an abandoned tannery site concerning injections of sodium dithionite as a chromate reductant for the vadose zone in combination with a pump-and-treat-method, allying the advantages of granulated zero valent iron (ZVI), are reported. Reduction amounts of chromate have been found up to 88% compared with initial values in the soil after a soil water exchange of 8 pore volumes within 2.5 months. Chromate concentrations in the pumped effluent have been reduced to under the detection limit of 0.005 mg/L by treatment with ZVI in the pilot plant. - Highlights: • Fe-granules show high Cr(VI)-reduction rates using fluidized bed conditions. • No respective negligible passivation effects on the surface of the iron granulates. • P and T-method by using ZVI in a FBR is very effective for Cr(VI) remediation. • The process provides no increase in salinity of the treated effluent

  11. Immersion autometallography: histochemical in situ capturing of zinc ions in catalytic zinc-sulfur nanocrystals.

    Science.gov (United States)

    Danscher, Gorm; Stoltenberg, Meredin; Bruhn, Mikkel; Søndergaard, Chris; Jensen, Dorete

    2004-12-01

    In the mid-1980s, two versions of Timm's original immersion sulfide silver method were published. The authors used immersion of tissue in a sulfide solution as opposed to Timm, who used immersion of tissue blocks in hydrogen sulfide-bubbled alcohol. The autometallography staining resulting from the "sulfide only immersion" was not particularly impressive, but the significance of this return to an old approach became obvious when Wenzel and co-workers presented their approach in connection with introduction by the Palmiter group of zinc transporter 3 (ZnT3). The Wenzel/Palmiter pictures are the first high-resolution, high-quality pictures taken from tissues in which free and loosely bound zinc ions have been captured in zinc-sulfur nanocrystals by immersion. The trick was to place formalin-fixed blocks of mouse brains in a solution containing 3% glutaraldehyde and 0.1% sodium sulfide, ingredients used for transcardial perfusion in the zinc-specific NeoTimm method. That the NeoTimm technique results in silver enhancement of zinc-sulfur nanocrystals has been proved by proton-induced X-ray multielement analyses (PIXE) and in vivo chelation with diethyldithiocarbamate (DEDTC). The aims of the present study were (a) to make the immersion-based capturing of zinc ions in zinc-sulfur nanocrystals work directly on sections and slices of fixed brain tissue, (b) to work out protocols that ensure zinc specificity and optimal quality of the staining, (c) to apply "immersion autometallography" (iZnSAMG) to other tissues that contain zinc-enriched (ZEN) cells, and (d) to make the immersion approach work on unfixed fresh tissue.

  12. ON-LINE NONLINEAR CHROMATICITY CORRECTION USING OFF-MOMENTUM TUNE RESPONSE MATRIX

    International Nuclear Information System (INIS)

    LUO, Y.; FISCHER, W.; MALISKY, N.; TEPIKIAN, S.; TROBJEVIC, D.

    2007-01-01

    In this article, we propose a method for the online nonlinear chromaticity correction at store in the Relativistic Heavy Ion Collider (RHIC). With 8 arc sextupole families in each RHIC ring, the nonlinear chromaticities can be minimized online by matching the off-momentum tunes onto the wanted tunes given by the linear chromaticities. The Newton method is used for this multi-dimensional nonlinear optimization, where the off-momentum tune response matrix with respect to sextupole strength changes is adopted. The off-momentum tune response matrix can be calculated with the online accelerator optics model or directly measured with the real beam. In this article, the correction algorithm for the RHIC is presented. Simulations are also carried out to verify the method. The preliminary results from the beam experiments taken place in the RHIC 2007 Au run are reviewed

  13. Effects of visual attention on chromatic and achromatic detection sensitivities.

    Science.gov (United States)

    Uchikawa, Keiji; Sato, Masayuki; Kuwamura, Keiko

    2014-05-01

    Visual attention has a significant effect on various visual functions, such as response time, detection and discrimination sensitivity, and color appearance. It has been suggested that visual attention may affect visual functions in the early visual pathways. In this study we examined selective effects of visual attention on sensitivities of the chromatic and achromatic pathways to clarify whether visual attention modifies responses in the early visual system. We used a dual task paradigm in which the observer detected a peripheral test stimulus presented at 4 deg eccentricities while the observer concurrently carried out an attention task in the central visual field. In experiment 1, it was confirmed that peripheral spectral sensitivities were reduced more for short and long wavelengths than for middle wavelengths with the central attention task so that the spectral sensitivity function changed its shape by visual attention. This indicated that visual attention affected the chromatic response more strongly than the achromatic response. In experiment 2 it was obtained that the detection thresholds increased in greater degrees in the red-green and yellow-blue chromatic directions than in the white-black achromatic direction in the dual task condition. In experiment 3 we showed that the peripheral threshold elevations depended on the combination of color-directions of the central and peripheral stimuli. Since the chromatic and achromatic responses were separately processed in the early visual pathways, the present results provided additional evidence that visual attention affects responses in the early visual pathways.

  14. Fluctuations in the prevalence of chromate allergy in Denmark and exposure to chrome-tanned leather.

    Science.gov (United States)

    Carøe, Caroline; Andersen, Klaus E; Thyssen, Jacob P; Mortz, Charlotte G

    2010-12-01

    A recent Danish study showed a significant increase in the prevalence of chromate contact allergy after the mid-1990s, probably as a result of exposure to leather products. To reproduce the results by analysing data from the period 1992-2009 at Odense University Hospital, Denmark. The temporal development in the occurrence of chromate contact allergy and assumed causative exposures were investigated. A retrospective analysis of patch test data was performed (n = 8483), and medical charts from patients with chromate allergy (n = 231) were reviewed. Comparisons were made using the χ(2) -test. A test of the reproducibility of the TRUE Test® was also performed. Logistic regression analyses were used to test for associations. No significant changes in the prevalence or exposure sources of chromate allergy during 1992-2009 were identified. Leather shoes (24.4%) were the most frequent exposure sources in chromate allergy, and were mainly registered in women, although the difference between men and women was not significant (P = 0.07). Cement and leather glove exposure occurred significantly more often in men than in women (P = 0.002). Foot dermatitis (40.3%) was the most frequent anatomical location, apart from hand eczema (60.6%). The reproducibility of the TRUE Test® was 93.3%. Apart from hand eczema, the most frequent clinical picture of chromate allergy was foot dermatitis caused by leather shoe exposure. A tendency for an increasing prevalence of chromate contact allergy from 1997 was shown, but no significant change was detectable. © 2010 John Wiley & Sons A/S.

  15. The Role of Luminance and Chromaticity on Symmetry Detection

    Directory of Open Access Journals (Sweden)

    Chia-Ching Wu

    2011-05-01

    Full Text Available We investigated the effect of luminance and chromaticity on symmetry detection with the noise masking paradigm. In each trial, a random dot noise mask was presented in both intervals. A symmetric target was randomly presented in one interval while a random dot control was presented in the other. The orientation of the symmetric axis of the target was either 45°or −45° diagonal. The task of the observer was to determine which interval contained a symmetric target. The dots in both the target and the mask was painted with 1 to 4 colors selected from white, black, red, green, blue and yellow. We measured the target density threshold at various noise densities. Our results showed that when the number of the colors in the images was equal, the thresholds were lower in the luminance conditions than in the chromaticity conditions. In addition, the thresholds decreased with the increment of the number of the colors in the images. This suggests that (1 the luminance symmetry detection mechanism is more sensitive than chromaticity one and (2 that, contrasted to the prediction of an uncertainty model, the diversity in color facilitates symmetry detection.

  16. Chromatic aberrations of electrostatic axisymmetric lenses produced by circular cylinders

    International Nuclear Information System (INIS)

    Baranova, L.A.; Ul'yanova, N.S.; Yavor, S.Ya.

    1989-01-01

    Ion beams both to test material and for technological processes have being used lately in science and technology more and more. Electrostatic lenses are used, as a rule, for such beam production. Coefficients of chromatic aberrration for a wide range of changes in lense parameters are calculated on the basis of analytical expressions to determine the potential in immerse and isolated lenses. The chromatic aberration coefficient is presented as a polynomial according to the degrees of reverse increase, that permits to calculate a circle of blurring of subject arbitrary position

  17. Mutual compensation of wakefield and chromatic effects of intense linac bunches

    International Nuclear Information System (INIS)

    Seeman, J.T.; Merminga, N.

    1990-05-01

    Mutual compensation of transverse and chromatic effects for intense electron bunches in a high-energy linac is a recent Novosibirsk idea which provides a new control of emittance enlargement. In this paper we elaborate on the principles and constraints for this new technique which requires careful matching of internal bunch parameters with external forces. With species values of the bunch length, bunch intensity, and klystron phasing, the transverse-wakefield-induced forces within the bunch can be cancelled by energy-dependent forces from the quadrupole lattice at all positions along the linac. Under these conditions the tolerances for quadrupole alignment, dipole stability, and injection launch errors are significantly relaxed. 7 refs., 8 figs

  18. Nucleolin modulates the subcellular localization of GDNF-inducible zinc finger protein 1 and its roles in transcription and cell proliferation

    International Nuclear Information System (INIS)

    Dambara, Atsushi; Morinaga, Takatoshi; Fukuda, Naoyuki; Yamakawa, Yoshinori; Kato, Takuya; Enomoto, Atsushi; Asai, Naoya; Murakumo, Yoshiki; Matsuo, Seiichi; Takahashi, Masahide

    2007-01-01

    GZF1 is a zinc finger protein induced by glial cell-line-derived neurotrophic factor (GDNF). It is a sequence-specific transcriptional repressor with a BTB/POZ (Broad complex, Tramtrack, Bric a brac/Poxvirus and zinc finger) domain and ten zinc finger motifs. In the present study, we used immunoprecipitation and mass spectrometry to identify nucleolin as a GZF1-binding protein. Deletion analysis revealed that zinc finger motifs 1-4 of GZF1 mediate its association with nucleolin. When zinc fingers 1-4 were deleted from GZF1 or nucleolin expression was knocked down by short interference RNA (siRNA), nuclear localization of GZF1 was impaired. These results suggest that nucleolin is involved in the proper subcellular distribution of GZF1. In addition, overexpression of nucleolin moderately inhibited the transcriptional repressive activity of GZF1 whereas knockdown of nucleolin expression by siRNA enhanced its activity. Thus, the repressive activity of GZF1 is modulated by the level at which nucleolin is expressed. Finally, we found that knockdown of GZF1 and nucleolin expression markedly impaired cell proliferation. These findings suggest that the physiological functions of GZF1 may be regulated by the protein's association with nucleolin

  19. Tune modulation due to synchrotron oscillations and chromaticity, and the dynamic aperture

    International Nuclear Information System (INIS)

    Parzen, G.

    1995-01-01

    A tracking study was done of the effects of a tune modulations, due to synchrotron oscillations and the tune dependence on momentum (chromaticity), on the dynamic aperture. The studies were done using several RHIC lattices and tracking runs of about 1 x 10 6 turns. The dynamic aperture was found to decrease roughly linearly with the amplitude of the tune modulation. Lower order non-linear resonances, like the 1/3 and 1/4 resonance are not crossed because of the tune modulation. Three different cases were studied, corresponding to RHIC lattices with different β*, and with different synchrotron oscillation amplitudes. In each case, the tune modulation amplitude was varied by changing the chromaticity. In each case, roughly the same result, was found. The result found here for the effect of a tune modulation due to chromaticity may be compared with the result found for the effect of a tune modulation due to a gradient ripple in the quadrupoles. The effect of a tune modulation due to a gradient ripple appears to be about 4 times stronger than the effect of a tune modulation due to chromaticity and synchrotron oscillations

  20. Chromatic and Achromatic Spatial Resolution of Local Field Potentials in Awake Cortex.

    Science.gov (United States)

    Jansen, Michael; Li, Xiaobing; Lashgari, Reza; Kremkow, Jens; Bereshpolova, Yulia; Swadlow, Harvey A; Zaidi, Qasim; Alonso, Jose-Manuel

    2015-10-01

    Local field potentials (LFPs) have become an important measure of neuronal population activity in the brain and could provide robust signals to guide the implant of visual cortical prosthesis in the future. However, it remains unclear whether LFPs can detect weak cortical responses (e.g., cortical responses to equiluminant color) and whether they have enough visual spatial resolution to distinguish different chromatic and achromatic stimulus patterns. By recording from awake behaving macaques in primary visual cortex, here we demonstrate that LFPs respond robustly to pure chromatic stimuli and exhibit ∼2.5 times lower spatial resolution for chromatic than achromatic stimulus patterns, a value that resembles the ratio of achromatic/chromatic resolution measured with psychophysical experiments in humans. We also show that, although the spatial resolution of LFP decays with visual eccentricity as is also the case for single neurons, LFPs have higher spatial resolution and show weaker response suppression to low spatial frequencies than spiking multiunit activity. These results indicate that LFP recordings are an excellent approach to measure spatial resolution from local populations of neurons in visual cortex including those responsive to color. © The Author 2014. Published by Oxford University Press.

  1. Neurochemical responses to chromatic and achromatic stimuli in the human visual cortex.

    Science.gov (United States)

    Bednařík, Petr; Tkáč, Ivan; Giove, Federico; Eberly, Lynn E; Deelchand, Dinesh K; Barreto, Felipe R; Mangia, Silvia

    2018-02-01

    In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called "blobs" and "interblobs") with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs. achromatic stimuli may be expected. The stimuli were optimized to evoke a similar load of neuronal activation as measured by the bold oxygenation level dependent (BOLD) contrast. Metabolic responses were assessed using functional 1 H MRS at 7 T in 12 subjects. During both chromatic and achromatic stimuli, we observed the typical increases in glutamate and lactate concentration, and decreases in aspartate and glucose concentration, that are indicative of increased glucose oxidation. However, within the detection sensitivity limits, we did not observe any difference between metabolic responses elicited by chromatic and achromatic stimuli. We conclude that the higher energy demands of activated blobs and interblobs are supported by similar increases in oxidative metabolism despite the different capacities of these neuronal populations.

  2. Anti-inflammatory, antinociceptive and ulcerogenic activity of a zinc-diclofenac complex in rats

    Directory of Open Access Journals (Sweden)

    L.H. Santos

    2004-08-01

    Full Text Available We investigated the anti-inflammatory, antinociceptive and ulcerogenic activity of a zinc-diclofenac complex (5.5 or 11 mg/kg in male Wistar rats (180-300 g, N = 6 and compared it to free diclofenac (5 or 10 mg/kg and to the combination of diclofenac (5 or 10 mg/kg and zinc acetate (1.68 or 3.5 mg/kg. The carrageenin-induced paw edema and the cotton pellet-induced granulomatous tissue formation models were used to assess the anti-inflammatory activity, and the Hargreaves model of thermal hyperalgesia was used to assess the antinociceptive activity. To investigate the effect of orally or intraperitoneally (ip administered drugs on cold-induced gastric lesions, single doses were administered before exposing the animals to a freezer (-18ºC for 45 min in individual cages. We also evaluated the gastric lesions induced by multiple doses of the drugs. Diclofenac plus zinc complex had the same anti-inflammatory and antinociceptive effects as diclofenac alone. Gastric lesions induced by a single dose administered per os and ip were reduced in the group treated with zinc-diclofenac when compared to the groups treated with free diclofenac or diclofenac plus zinc acetate. In the multiple dose treatment, the complex induced a lower number of the most severe lesions when compared to free diclofenac and diclofenac plus zinc acetate. In conclusion, the present study demonstrates that the zinc-diclofenac complex may represent an important therapeutic alternative for the treatment of rheumatic and inflammatory conditions, as its use may be associated with a reduced incidence of gastric lesions.

  3. Influence of acids on the zinc conversion process with molybdate

    International Nuclear Information System (INIS)

    Silva, Cosmelina Goncalves da; Margarit-Mattos, Isabel Cristina Pereira; Mattos, Oscar Rosa; Barcia, Oswaldo Esteves

    2010-01-01

    Molybdate conversion coatings have been evaluated as possible alternative to the chromate ones. The acid used in the pH adjustment of the conversion baths exerts great influence on the anti corrosive properties of these coatings. The aim of this work was to verify the role of phosphoric and sulfuric acids on the zinc conversion process with molybdate. The techniques used were: chronopotentiometry, electrochemical impedance spectroscopy (EIS) and interfacial pH measurements. The surface characterization was made with scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The chronopotentiometry results have shown that the influence of the variation of the electrode rotation speed on the conversion process is acid-dependent: the acid influences the mass transport during the conversion. The EIS measures have suggested that the conversion mechanism does not change with the acid, being the coatings thicker when H_2SO_4 is used than the obtained with H_3PO_4. The pH interfacial results have shown a pH increase more significant for the bath with H_2SO_4, indicating a fastest kinetic of zinc dissolution. It was identified the presence of Mo in all analyzed coatings, for both acids, and P in those obtained with H_3PO_4. (author)

  4. Pseudomonas aeruginosa Trent and zinc homeostasis.

    Science.gov (United States)

    Davies, Corey B; Harrison, Mark D; Huygens, Flavia

    2017-09-01

    Pseudomonas aeruginosa is a Gram-negative pathogen and the major cause of mortality in patients with cystic fibrosis. The mechanisms that P. aeruginosa strains use to regulate intracellular zinc have an effect on infection, antibiotic resistance and the propensity to form biofilms. However, zinc homeostasis in P. aeruginosa strains of variable infectivity has not been compared. In this study, zinc homeostasis in P. aeruginosa Trent, a highly infectious clinical strain, was compared to that of a laboratory P. aeruginosa strain, ATCC27853. Trent was able to tolerate higher concentrations of additional zinc in rich media than ATCC27853. Further, pre-adaptation to additional zinc enhanced the growth of Trent at non-inhibitory concentrations but the impact of pre-adaption on the growth of ATCC27853 under the same conditions was minimal. The results establish clear differences in zinc-induced responses in Trent and ATCC27853, and how zinc homeostasis can be a promising target for the development of novel antimicrobial strategies for P. aeruginosa infection in cystic fibrosis patients. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Effect of Annealing Time of YAG:Ce3+ Phosphor on White Light Chromaticity Values

    Science.gov (United States)

    Abd, Husnen R.; Hassan, Z.; Ahmed, Naser M.; Almessiere, Munirah Abdullah; Omar, A. F.; Alsultany, Forat H.; Sabah, Fayroz A.; Osman, Ummu Shuhada

    2018-02-01

    Yttrium and aluminium nitrate phosphors doped with cerium nitrate and mixed with urea (fuel) are prepared by using microwave-induced combustion synthesis according to the formula Y(3-0.06)Al5O12:0.06Ce3+ (YAG:Ce3+) to produce white light emitting diodes by conversion from blue indium gallium nitride-light emitting diode chips. The sintering time with fixed temperature (1050°C) for phosphor powder was optimized and found to be 5 h. The crystallinity, structure, chemical composition, luminescent properties with varying currents densities and chromaticity were characterized by x-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, photoluminescence emission, electroluminescence and standard CIE 1931 chromaticity diagram, respectively. The energy levels of Ce3+ in YAG were discussed based on its absorption and excitation spectra. The results show that the obtained YAG:Ce3+ phosphor sintered for 5 h has good crystallinity with pure phase, low agglomerate with spherical shaped particles and strong yellow emission, offering cool-white LED with tuneable correlated color temperature and a good color rendering index compared to those prepared by sintering for 2 h and as-prepared phosphor powders.

  6. Implication of extracellular zinc exclusion by recombinant human calprotectin (MRP8 and MRP14 from target cells in its apoptosis-inducing activity

    Directory of Open Access Journals (Sweden)

    Satoru Yui

    2002-01-01

    Full Text Available Background: Calprotectin is a calcium-binding and zinc-binding protein complex that is abundant in the cytosol of neutrophils. This factor is composed of 8 and 14 kDa subunits, which have also been termed migration inhibitory factor-related proteins MRP8 and MRP14. We previously reported that rat calprotectin purified from inflammatory neutrophils induces apoptosis of various tumor cells or normal fibroblasts in a zinc-reversible manner.

  7. BWR fuel experience with zinc injection

    International Nuclear Information System (INIS)

    Levin, H.A.; Garcia, S.E.

    1995-01-01

    In 1982 a correlation between low primary recirculation system dose rates in BWR's and the presence of ionic zinc in reactor water was identified. The source of the zinc was primarily from Admiralty brass condensers. Plants with brass condensers are called ''natural zinc'' plants. Brass condensers were also a source of copper that was implicated in crude induced localized corrosion (CILC) fuel failures. In 1986 the first BWR intentionally injected zinc for the benefits of dose rate control. Although zinc alone was never implicated in fuel degradation of failures, a comprehensive fuel surveillance program was initiated to monitor fuel performance. Currently there are 14 plants that are injecting zinc. Six of these plants are also on hydrogen water chemistry. This paper describes the effect on both Zircaloy corrosion and the cruding characteristics as a result of these changes in water chemistry. Fuel rod corrosion was found to be independent of the specific water chemistry of the plants. The corrosion behavior was the same with the additions of zinc alone or zinc plus hydrogen and well within the operating experience for fuel without either of these additions. No change was observed in the amounts of crude deposited on the fuel rods, both for the adherent and loosely held deposits. One of the effects of the zinc addition was the trend to form more of the zinc rich iron spinel in the fuel deposits rather than the hematite deposits that are predominantly formed with non additive water chemistry

  8. ZINC-INDUCED EGF RECEPTOR SIGNALING REQUIRES SRC-MEDIATED PHOSPHORYLATION OF THE EGF RECEPTOR ON TYROSINE 845 (Y845)

    Science.gov (United States)

    ZINC-INDUCED EGF RECEPTOR SIGNALING REQUIRES Src-MEDIATED PHOSPHORYLATION OF THE EGF RECEPTOR ON TYROSINE 845 (Y845)Weidong Wu1, Lee M. Graves2, Gordon N. Gill3 and James M. Samet4 1Center for Environmental Medicine and Lung Biology; 2Department of Pharmacology, University o...

  9. Cytosolic labile zinc: a marker for apoptosis in the developing rat brain.

    Science.gov (United States)

    Lee, Joo-Yong; Hwang, Jung Jin; Park, Mi-Ha; Koh, Jae-Young

    2006-01-01

    Cytosolic zinc accumulation was thought to occur specifically in neuronal death (necrosis) following acute injury. However, a recent study demonstrated that zinc accumulation also occurs in adult rat neurons undergoing apoptosis following target ablation, and in vitro experiments have shown that zinc accumulation may play a causal role in various forms of apoptosis. Here, we examined whether intraneuronal zinc accumulation occurs in central neurons undergoing apoptosis during development. Embryonic and newborn Sprague-Dawley rat brains were double-stained for terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) detection of apoptosis and immunohistochemical detection of stage-specific neuronal markers, such as nestin, proliferating cell nuclear antigen (PCNA), TuJ1 and neuronal nuclear specific protein (NeuN). The results revealed that apoptotic cell death occurred in neurons of diverse stages (neural stem cells, and dividing, young and adult neurons) throughout the brain during the embryonic and early postnatal periods. Further staining of brain sections with acid fuchsin or zinc-specific fluorescent dyes showed that all of the apoptotic neurons were acidophilic and contained labile zinc in their cell bodies. Cytosolic zinc accumulation was also observed in cultured cortical neurons undergoing staurosporine- or sodium nitroprusside (SNP)-induced apoptosis. In contrast, zinc chelation with CaEDTA or N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) reduced SNP-induced apoptosis but not staurosporine-induced apoptosis, indicating that cytosolic zinc accumulation does not play a causal role in all forms of apoptosis. Finally, the specific cytosolic zinc accumulation may have a practical application as a relatively simple marker for neurons undergoing developmental apoptosis.

  10. Measurement of chromatic dispersion of microstructured polymer fibers by white-light spectral interferometry

    DEFF Research Database (Denmark)

    Hlubina, Petr; Ciprian, Dalibor; Frosz, Michael Henoch

    2009-01-01

    We present a white-light spectral interferometric method for measuring the chromatic dispersion of microstructured fibers made of polymethyl methacrylate (PMMA). The method uses an unbalanced Mach-Zehnder interferometer with the fiber of known length placed in one of the interferometer arms...... of the method by measuring the wavelength dependence of the differential group refractive index of a pure silica fiber. We apply a five-term power series fit to the measured data and confirm by its differentiation that the chromatic dispersion of pure silica glass agrees well with theory. Second, we measure...... the chromatic dispersion for the fundamental mode supported by two different PMMA microstructured fibers, the multimode fiber and the large-mode area one....

  11. CHROMATE INHIBITION OF THE LOCALIZED CORROSION OF ALUMINUM: MEASUREMENTS OF ELECTROCHEMICAL TRANSIENTS

    International Nuclear Information System (INIS)

    SASAKI, K.; ISAACS, H.S.

    2001-01-01

    We investigated the inhibition by chromate ions of the localized corrosion of aluminum by electrochemical transient measurements. In agreement with other work, the measurements demonstrated that chromate is a cathodic inhibitor for aluminum in open circuit. The reduction of hexavalent chromium to trivalent chromium is assumed to take place on catalyzed sites of the surface. The resulting products inhibit oxygen reduction reactions at these sites, thereby retarding pitting corrosion

  12. Microcirculatory effects of zinc on fructose-fed hamsters.

    Science.gov (United States)

    Castiglione, R C; Barros, C M M R; Boa, B C S; Bouskela, E

    2016-04-01

    Fructose is a major dietary component directly related to vascular dysfunction and diseases such as obesity, diabetes, and hypertension. Zinc is considered a non-pharmacological alternative for treating diabetes due to its antioxidant and hyperglycemia-lowering effects in diabetic animals. Therefore, the aim of this study was to evaluate the effects of dietary zinc supplementation on the microcirculatory parameters of fructose-fed hamsters. Male hamsters (Mesocricetus auratus) were fed drinking water substituted by 10% fructose solution for 60 days, whereas control animals were fed drinking water alone. Their microcirculatory function was evaluated using cheek pouch preparation, as well as their blood glucose and serum insulin levels. Their microcirculatory responses to acetylcholine (ACh, an endothelium-dependent vasodilator) and to sodium nitroprusside (SNP, an endothelium-independent vasodilator) as well as the increase in macromolecular permeability induced by 30 min of ischemia/reperfusion (I/R) were noted. Endothelium-dependent vasodilation was significantly increased in control animals with high zinc supplementation compared to the groups without zinc supplementation. Zinc was able to protect against plasma leakage induced by I/R in all control and fructose-fed groups, although the microvascular permeability was higher in animals fed drinking water substituted by 10% fructose solution compared to those fed filtered drinking water alone. Our results indicate that dietary zinc supplementation can improve microvascular dysfunction by increasing endothelial-dependent dilatation and reducing the increase in macromolecular permeability induced by I/R in fructose-fed animals. Copyright © 2015 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  13. Development of Chromatic Induction in Infancy

    Science.gov (United States)

    Okamura, Hiromi; Kanazawa, So; Yamaguchi, Masami K.

    2007-01-01

    The perception of colour in an embedded field is affected by the surround colour. This phenomenon is known as chromatic induction. In the present study we investigated whether the colour perception by infants aged 5-7 months could be affected by the surround colour. In Experiments 1 and 2 each stimulus was composed of an array of six squares in…

  14. Contradictory effect of chromate inhibitor on corrosive wear of aluminium alloy

    International Nuclear Information System (INIS)

    Pokhmurskii, V.I.; Zin, I.M.; Vynar, V.A.; Bily, L.M.

    2011-01-01

    Research highlights: → Corrosive wear of aluminium alloy in inhibited artificial acid rain was studied. → Tribometer with linear reciprocating ball-on-flat geometry was used.→ Corrosion potential, polarization current and friction coefficient were measured. → Chromate decreases corrosion of aluminium alloy under wear conditions. → Chromate in general accelerates corrosive wear of the alloy in acid rain. - Abstract: The corrosive wear of D16T aluminium alloy in artificial acid rain was studied. A special tribometer with the linear reciprocating ball-on-flat geometry was used. The setup allows to measure simultaneously an open circuit potential, to carry out potentiostatic and potentiodynamic polarization studies of the alloy corrosion and to record the friction coefficient. It was established that the addition of strontium chromate inhibitor to the working environment decreases an electrochemical corrosion of the aluminium alloy under wear conditions, but in general accelerates its destruction due to insufficient wear resistance of a formed surface film.

  15. Construction and application of a zinc-specific biosensor for assessing the immobilization and bioavailability of zinc in different soils

    International Nuclear Information System (INIS)

    Liu Pulin; Huang Qiaoyun; Chen Wenli

    2012-01-01

    The inducibility and specificity of different czcRS operons in Pseudomonas putida X4 were studied by lacZ gene fusions. The data of β-glycosidase activity confirmed that the czcR3 promoter responded quantitatively to zinc. A zinc-specific biosensor, P. putida X4 (pczcR3GFP), was constructed by fusing a promoterless enhanced green fluorescent protein (egfp) gene with the czcR3 promoter in the chromosome of P. putida X4. In water extracts of four different soils amended with zinc, the reporter strain detected about 90% of the zinc content of the samples. Both the bioavailability assessment and the sequential extraction analysis demonstrated that the immobilization of zinc was highly dependent on the physico-chemical properties of soils. The results also showed that the lability of zinc decreased over time. It is concluded that the biosensor constitutes an alternative system for the convenient evaluation of zinc toxicity in the environment. - Highlights: ► A zinc-specific bacterial biosensor was developed. ► Four spiked soils were used to test the application of this biosensor. ► The bioavailable zinc in soil-water extracts decreased due to aging. ► The immobilization and speciation of zinc were highly dependent on the soil type. - The immobilization and bioavailability of zinc in soil were investigated as a function of soil type and aging by a newly constructed zinc-specific biosensor coupled with chemical analysis.

  16. The Zinc Finger of Prolyl Hydroxylase Domain Protein 2 Is Essential for Efficient Hydroxylation of Hypoxia-Inducible Factor α.

    Science.gov (United States)

    Arsenault, Patrick R; Song, Daisheng; Chung, Yu Jin; Khurana, Tejvir S; Lee, Frank S

    2016-09-15

    Prolyl hydroxylase domain protein 2 (PHD2) (also known as EGLN1) is a key oxygen sensor in mammals that posttranslationally modifies hypoxia-inducible factor α (HIF-α) and targets it for degradation. In addition to its catalytic domain, PHD2 contains an evolutionarily conserved zinc finger domain, which we have previously proposed recruits PHD2 to the HSP90 pathway to promote HIF-α hydroxylation. Here, we provide evidence that this recruitment is critical both in vitro and in vivo We show that in vitro, the zinc finger can function as an autonomous recruitment domain to facilitate interaction with HIF-α. In vivo, ablation of zinc finger function by a C36S/C42S Egln1 knock-in mutation results in upregulation of the erythropoietin gene, erythrocytosis, and augmented hypoxic ventilatory response, all hallmarks of Egln1 loss of function and HIF stabilization. Hence, the zinc finger ordinarily performs a critical positive regulatory function. Intriguingly, the function of this zinc finger is impaired in high-altitude-adapted Tibetans, suggesting that their adaptation to high altitude may, in part, be due to a loss-of-function EGLN1 allele. Thus, these findings have important implications for understanding both the molecular mechanism of the hypoxic response and human adaptation to high altitude. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  17. Effect of DHA and CoenzymeQ10 Against Aβ- and Zinc-Induced Mitochondrial Dysfunction in Human Neuronal Cells

    Directory of Open Access Journals (Sweden)

    Nadia Sadli

    2013-07-01

    Full Text Available Background: Beta-amyloid (Aβ protein is a key factor in the pathogenesis of Alzheimer's disease (AD and it has been reported that mitochondria is involved in the biochemical pathway by which Aβ can lead to neuronal dysfunction. Coenzyme Q10 (CoQ10 is an essential cofactor involved in the mitochondrial electron transport chain and has been suggested as a potential therapeutic agent in AD. Zinc toxicity also affects cellular energy production by decreasing oxygen consumption rate (OCR and ATP turnover in human neuronal cells, which can be restored by the neuroprotective effect of docosahexaenoic acid (DHA. Method: In the present study, using Seahorse XF-24 Metabolic Flux Analysis we investigated the effect of DHA and CoQ10 alone and in combination against Aβ- and zinc-mediated changes in the mitochondrial function of M17 neuroblastoma cell line. Results: Here, we observed that DHA is specifically neuroprotective against zinc-triggered mitochondrial dysfunction, but does not directly affect Aβ neurotoxicity. CoQ10 has shown to be protective against both Aβ- and zinc-induced alterations in mitochondrial function. Conclusion: Our results indicate that DHA and CoQ10 may be useful for the prevention, treatment and management of neurodegenerative diseases such as AD.

  18. Speed and the coherence of superimposed chromatic gratings.

    Science.gov (United States)

    Bosten, J M; Smith, L; Mollon, J D

    2016-05-01

    On the basis of measurements of the perceived coherence of superimposed drifting gratings, Krauskopf and Farell (1990) proposed that motion is analysed independently in different chromatic channels. They found that two gratings appeared to slip if each modulated one of the two 'cardinal' color mechanisms S/(L+M) and L/(L+M). If the gratings were defined along intermediate color directions, observers reported a plaid, moving coherently. We hypothesised that slippage might occur in chromatic gratings if the motion signal from the S/(L+M) channel is weak and equivalent to a lower speed. We asked observers to judge coherence in two conditions. In one, S/(L+M) and L/(L+M) gratings were physically the same speed. In the other, the two gratings had perceptually matched speeds. We found that the relative incoherence of cardinal gratings is the same whether gratings are physically or perceptually matched in speed. Thus our hypothesis was firmly contradicted. In a control condition, observers were asked to judge the coherence of stationary gratings. Interestingly, the difference in judged coherence between cardinal and intermediate gratings remained as strong as it was when the gratings moved. Our results suggest a possible alternative interpretation of Krauskopf and Farell's result: the processes of object segregation may precede the analysis of the motion of chromatic gratings, and the same grouping signals may prompt object segregation in the stationary and moving cases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Evaluation of chromatic cues for trapping Bactrocera tau.

    Science.gov (United States)

    Li, Lei; Ma, Huabo; Niu, Liming; Han, Dongyin; Zhang, Fangping; Chen, Junyu; Fu, Yueguan

    2017-01-01

    Trapping technology based on chromatic cues is an important strategy in controlling Tephritidae (fruit flies). The objectives of this present study were to evaluate the preference of Bactrocera tau for different chromatic cues, and to explore an easy method to print and reproduce coloured paper. Chromatic cues significantly affected the preference of adult B. tau. Wavelengths in the 515-604 nm range were the suitable wavelengths for trapping B. tau. Different-day-old B. tau had different colour preferences. Virtual wavelengths of 595 nm (yellow) and 568 nm (yellowish green) were the optimum wavelengths for trapping 5-7-day-old B. tau and 30-32-day-old B. tau respectively. The trap type and height significantly influenced B. tau attraction efficiency. The number of B. tau on coloured traps hung perpendicular to plant rows was not significantly higher than the number on traps hung parallel to plant rows. The quantisation of colour on the basis of Bruton's wavelength to RGB function can serve as an alternative method for printing and reproducing coloured paper, but a corrected equation should be established between the theoretical wavelength and actual wavelength of coloured paper. Results show that a compound paper coloured yellow (595 nm) and yellowish green (568 nm) installed at 60 and 90 cm above the ground shows the maximum effect for trapping B. tau. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  20. Chromatic signals control proboscis movements during hovering flight in the hummingbird hawkmoth Macroglossum stellatarum.

    Science.gov (United States)

    Goyret, Joaquín; Kelber, Almut

    2012-01-01

    Most visual systems are more sensitive to luminance than to colour signals. Animals resolve finer spatial detail and temporal changes through achromatic signals than through chromatic ones. Probably, this explains that detection of small, distant, or moving objects is typically mediated through achromatic signals. Macroglossum stellatarum are fast flying nectarivorous hawkmoths that inspect flowers with their long proboscis while hovering. They can visually control this behaviour using floral markings known as nectar guides. Here, we investigate whether this is mediated by chromatic or achromatic cues. We evaluated proboscis placement, foraging efficiency, and inspection learning of naïve moths foraging on flower models with coloured markings that offered either chromatic, achromatic or both contrasts. Hummingbird hawkmoths could use either achromatic or chromatic signals to inspect models while hovering. We identified three, apparently independent, components controlling proboscis placement: After initial contact, 1) moths directed their probing towards the yellow colour irrespectively of luminance signals, suggesting a dominant role of chromatic signals; and 2) moths tended to probe mainly on the brighter areas of models that offered only achromatic signals. 3) During the establishment of the first contact, naïve moths showed a tendency to direct their proboscis towards the small floral marks independent of their colour or luminance. Moths learned to find nectar faster, but their foraging efficiency depended on the flower model they foraged on. Our results imply that M. stellatarum can perceive small patterns through colour vision. We discuss how the different informational contents of chromatic and luminance signals can be significant for the control of flower inspection, and visually guided behaviours in general.

  1. Zinc and the modulation of redox homeostasis

    Science.gov (United States)

    Oteiza, Patricia I.

    2012-01-01

    Zinc, a redox inactive metal, has been long viewed as a component of the antioxidant network, and growing evidence points to its involvement in redox-regulated signaling. These actions are exerted through several mechanisms based on the unique chemical and functional properties of zinc. Overall, zinc contributes to maintain the cell redox balance through different mechanisms including: i) the regulation of oxidant production and metal-induced oxidative damage; ii) the dynamic association of zinc with sulfur in protein cysteine clusters, from which the metal can be released by nitric oxide, peroxides, oxidized glutathione and other thiol oxidant species; iii) zinc-mediated induction of the zinc-binding protein metallothionein, which releases the metal under oxidative conditions and act per se scavenging oxidants; iv) the involvement of zinc in the regulation of glutathione metabolism and of the overall protein thiol redox status; and v) a direct or indirect regulation of redox signaling. Findings of oxidative stress, altered redox signaling, and associated cell/tissue disfunction in cell and animal models of zinc deficiency, stress the relevant role of zinc in the preservation of cell redox homeostasis. However, while the participation of zinc in antioxidant protection, redox sensing, and redox-regulated signaling is accepted, the involved molecules, targets and mechanisms are still partially known and the subject of active research. PMID:22960578

  2. Visual sensitivity for luminance and chromatic stimuli during the execution of smooth pursuit and saccadic eye movements.

    Science.gov (United States)

    Braun, Doris I; Schütz, Alexander C; Gegenfurtner, Karl R

    2017-07-01

    Visual sensitivity is dynamically modulated by eye movements. During saccadic eye movements, sensitivity is reduced selectively for low-spatial frequency luminance stimuli and largely unaffected for high-spatial frequency luminance and chromatic stimuli (Nature 371 (1994), 511-513). During smooth pursuit eye movements, sensitivity for low-spatial frequency luminance stimuli is moderately reduced while sensitivity for chromatic and high-spatial frequency luminance stimuli is even increased (Nature Neuroscience, 11 (2008), 1211-1216). Since these effects are at least partly of different polarity, we investigated the combined effects of saccades and smooth pursuit on visual sensitivity. For the time course of chromatic sensitivity, we found that detection rates increased slightly around pursuit onset. During saccades to static and moving targets, detection rates dropped briefly before the saccade and reached a minimum at saccade onset. This reduction of chromatic sensitivity was present whenever a saccade was executed and it was not modified by subsequent pursuit. We also measured contrast sensitivity for flashed high- and low-spatial frequency luminance and chromatic stimuli during saccades and pursuit. During saccades, the reduction of contrast sensitivity was strongest for low-spatial frequency luminance stimuli (about 90%). However, a significant reduction was also present for chromatic stimuli (about 58%). Chromatic sensitivity was increased during smooth pursuit (about 12%). These results suggest that the modulation of visual sensitivity during saccades and smooth pursuit is more complex than previously assumed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Joint Test Protocol: Environmentally Friendly Zirconium Oxide Pretreatment Demonstration

    Science.gov (United States)

    2013-12-01

    and compliance issues associated with the use of zinc phosphate and chromate/ chrome containing conversion coatings while maintaining military...safety, and occupational health risks associated with the use of zinc phosphate and chromate/ chrome -containing conversion coatings. There is a need to...zirconium-based pretreatment will be shown to be both environmentally acceptable (no hazardous air pollutants or heavy metals such as hexavalent chromium

  4. Alternatives To Cadmium Plated Military Connectors

    Science.gov (United States)

    2011-08-30

    from Feb 2011 Asets Defense conference  Amphenol Aerospace Operations report. 9/21/2011 10 Chromate finish  Hexavalent chrome was targeted by DOD...Fluorocarbon Zinc-Nickel Pure Dense Aluminum  Zinc-Nickel and Aluminum currently contain hexavalent chromate. Nickel-Fluorocarbon requires no...to lack of available drop in replacements, but this will change as alternatives become available.  Trivalent chrome and other non- chrome

  5. Protective Role of L- Carnitine and Zinc against γ-Radiation induced Cardiac and testicular Disorders in Albino Rats

    International Nuclear Information System (INIS)

    Ramadan, F. L.; Abdel-Monem, D.D.; Ismail, N.H.

    2013-01-01

    L-Carnitine is a dipeptide amino acid necessary for fat metabolism, it provides energy by transporting long-chain fatty acids to mitochondria to act as a fuel and it is considered a powerful antioxidant. In addition, zinc is an essential mineral which helps to increase the secretion of male sex hormones and raises the sperm count, so its combination with L-carnitine is useful for the fertility process. The present study aims to evaluate the potency of L-carnitine and zinc as radio- protective and curative agent pre and after exposure to γ-radiation through biochemical, histological, morphological abnormalities of sperms and DNA damage in the sperms induced by γ-irradiation by comet assay. Animals received L-carnitine (LC) and zinc (Zn) orally at the dose 9.45 mg/100 gm body wt./day for successive 20 days and then exposed to whole body gamma radiation at the dose 4 Gy (1 Gy for 4 days, day after day) on the 7th day from treatment with antioxidant. Histological examinations of heart and testis tissues showed that administration of LC and Zn have attenuated radiation induced damage and improved tissues architecture. Moreover, the observed amelioration in the tissues was accompanied by a remarkable decrease of their lipid peroxide levels (malondialdehyde (MDA)), together with an increase in glutathione peroxidase (GSHPx) and superoxide dismutase (SOD) activities. Hormonal determinations of serum testosterone (T), follicular stimulating hormone (FSH) and luteinizing hormone (LH) which carried out for fertility assessment showed that whole body γ-irradiation of rats induced significant decrease in serum testosterone while FSH and LH were significantly increased as compared with control group. On the other hand, irradiation caused significant elevation in the total number of abnormal head, and / or tail of sperms in comparison to the control rats. The comet assay showed that exposure to γ-radiation induced DNA damage of sperms (tail moment values).

  6. Symptomatic zinc deficiency in experimental zinc deprivation.

    OpenAIRE

    Taylor, C M; Goode, H F; Aggett, P J; Bremner, I; Walker, B E; Kelleher, J

    1992-01-01

    An evaluation of indices of poor zinc status was undertaken in five male subjects in whom dietary zinc intake was reduced from 85 mumol d-1 in an initial phase of the study to 14 mumol d-1. One of the subjects developed features consistent with zinc deficiency after receiving the low zinc diet for 12 days. These features included retroauricular acneform macullo-papular lesions on the face, neck, and shoulders and reductions in plasma zinc, red blood cell zinc, neutrophil zinc and plasma alkal...

  7. Sextupole correction for a ring with large chromaticity and the influence of magnetic errors on its parameters

    International Nuclear Information System (INIS)

    Kamiya, Y.; Katoh, M.; Honjo, I.

    1987-01-01

    A future ring with a low emittance and large circumference, specifically dedicated to a synchrotron light source, will have a large chromaticity, so that it is important to employ a sophisticated sextupole correction as well as the design of linear lattice to obtain the stable beam. The authors tried a method of sextupole correction for a lattice with a large chromaticity and small dispersion function. In such a lattice the sextupole magnets are obliged to become large in strength to compensate the chromaticity. Then the nonlinear effects of the sextupole magnets will become more serious than their chromatic effects. Furthermore, a ring with strong quadrupole magnets to get a very small emittance and with strong sextupole magnets to compensate the generated chromaticity will be very sensitive to their magnetic errors. The authors also present simple formulae to evaluate the effects on the beam parameters. The details will appear in a KEK Report

  8. Joint IQ Skew and Chromatic Dispersion Estimation for Coherent Optical Communication Receivers

    DEFF Research Database (Denmark)

    Medeiros Diniz, Júlio César; Porto da Silva, Edson; Piels, Molly

    2016-01-01

    A low-complexity scanning method for joint estimation of receiver IQ skew and chromatic dispersion is proposed. This method shows less than 1 ps skew error for a 1200-km 32-GBd DP-16QAM optical transmission experiment.......A low-complexity scanning method for joint estimation of receiver IQ skew and chromatic dispersion is proposed. This method shows less than 1 ps skew error for a 1200-km 32-GBd DP-16QAM optical transmission experiment....

  9. Removal of chromate in a permeable reactive barrier using zero-valent iron

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Locht, T

    2002-01-01

    Chromate is a commonly found groundwater contaminant. Permeable reactive barriers containing zero-valent iron as iron filings are able to remove the chromate by a combined reduction/precipitation reaction. However, due to the passivation of the reduction capability of the iron surfaces by the pre......). Mixing in sand had no significant enhancing effect on the removal capacity, in contrast to a pH adjustment of the groundwater to pH 4, which significantly increased the removal capacity....

  10. Influence of storage duration and processing on chromatic attributes and flavonoid content of moxa floss.

    Science.gov (United States)

    Lim, Min Yee; Huang, Jian; Zhao, Bai-xiao; Zou, Hui-qin; Yan, Yong-hong

    2016-01-01

    Moxibustion is an important traditional Chinese medicine therapy using heat from ignited moxa floss for disease treatment. The purpose of the present study is to establish a reproducible method to assess the color of moxa floss, discriminate the samples based on chromatic coordinates and explore the relationship between chromatic coordinates and total flavonoid content (TFC). Moxa floss samples of different storage years and production ratios were obtained from a moxa production factory in Henan Province, China. Chromatic coordinates (L*, a* and b*) were analyzed with an ultraviolet-visible spectrophotometer and the chroma (C*) and hue angle (h°) values were calculated. TFC was determined by a colorimetric method. Data were analyzed with correlation, principal component analysis (PCA). Significant differences in the chromatic values and TFC were observed among samples of different storage years and production ratios. Samples of higher production ratio displayed higher chromatic characteristics and lower TFC. Samples of longer storage years contained higher TFC. Preliminary separation of moxa floss production ratio was obtained by means of color feature maps developed using L*-a* or L*-b* as coordinates. PCA allowed the separation of the samples from their storage years and production ratios based on their chromatic characteristics and TFC. The use of a colorimetric technique and CIELAB coordinates coupled with chemometrics can be practical and objective for discriminating moxa floss of different storage years and production ratios. The development of color feature maps could be used as a model for classifying the color grading of moxa floss.

  11. Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

    Science.gov (United States)

    Cho, Minsu; Hu, Guanggan; Caza, Mélissa; Horianopoulos, Linda C; Kronstad, James W; Jung, Won Hee

    2018-01-01

    Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

  12. 100-D Area In Situ Redox Treatability Test for Chromate-Contaminated Groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Mark D.; Vermeul, Vincent R.; Szecsody, James E.; Fruchter, Jonathan S.

    2000-10-12

    A treatability test was conducted for the In Situ Redox Manipulation (ISRM) technology at the 100 D Area of the U. S. Department of Energy's Hanford Site. The target contaminant was dissolved chromate in groundwater. The ISRM technology creates a permeable subsurface treatment zone to reduce mobile chromate in groundwater to an insoluble form. The ISRM permeable treatment zone is created by reducing ferric iron to ferrous iron within the aquifer sediments, which is accomplished by injecting aqueous sodium dithionite into the aquifer and then withdrawing the reaction products. The goal of the treatability test was to create a linear ISRM barrier by injecting sodium dithionite into five wells. Well installation and site characterization activities began in spring 1997; the first dithionite injection took place in September 1997. The results of this first injection were monitored through the spring of 1998. The remaining four dithionite injections were carried out in May through July of 1998.These five injections created a reduced zone in the Hanford unconfined aquifer approximately 150 feet in length (perpendicular to groundwater flow) and 50 feet wide. The reduced zone extended over the thickness of the unconfined zone. Analysis of post-emplacement groundwater samples showed concentrations of chromate, in the reduced zone decreased from approximately 1.0 mg/L before the tests to below analytical detection limits (<0.007 mg/L). Chromate concentrations also declined in downgradient monitoring wells to as low as 0.020 mg/L. These data, in addition to results from pre-test reducible iron characterization, indicate the barrier should be effective for 20 to 25 years. The 100-D Area ISRM barrier is being expanded to a length of up to 2,300 ft to capture a larger portion of the chromate plume.

  13. The structure of chromatic polynomials of planar triangulations and implications for chromatic zeros and asymptotic limiting quantities

    International Nuclear Information System (INIS)

    Shrock, Robert; Xu Yan

    2012-01-01

    We present an analysis of the structure and properties of chromatic polynomials P(G pt,m-vector, q) of one-parameter and multi-parameter families of planar triangulation graphs G pt,m-vector , where m-vector = (m 1 ,…,m p ) is a vector of integer parameters. We use these to study the ratio of |P(G pt,m-vector, τ+1)| to the Tutte upper bound (τ − 1) n−5 , where τ=(1+√5)/2 and n is the number of vertices in G pt,m-vector . In particular, we calculate limiting values of this ratio as n → ∞ for various families of planar triangulations. We also use our calculations to analyze zeros of these chromatic polynomials. We study a large class of families G pt,m-vector with p = 1 and p = 2 and show that these have a structure of the form P(G pt,m ,q) = c G pt ,1 λ 1 m + c G pt ,2 λ 2 m + c G pt ,3 λ 3 m for p = 1, where λ 1 = q − 2, λ 2 = q − 3, and λ 3 = −1, and P(G pt,m-vector ,q) =Σ i 1 =1 3 Σ i 2 =1 3 c G pt ,i 1 i 2 λ i 1 m 1 λ i 2 m 2 for p = 2. We derive properties of the coefficients c G pt ,i-vector and show that P(G pt,m-vector ,q) has a real chromatic zero that approaches (1/2)(3+√5) as one or more of the m i → ∞. The generalization to p ⩾ 3 is given. Further, we present a one-parameter family of planar triangulations with real zeros that approach 3 from below as m → ∞. Implications for the ground-state entropy of the Potts antiferromagnet are discussed. (paper)

  14. Hexavalent chromium induces chromosome instability in human urothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Wise, Sandra S. [Wise Laboratory of Environmental and Genetic Toxicology, Maine Center for Toxicology and Environmental Health, Department of Applied Medical Science, University of Southern Maine, Science Building, 96 Falmouth Street, Portland, ME 04103 (United States); Holmes, Amie L. [Wise Laboratory of Environmental and Genetic Toxicology, Maine Center for Toxicology and Environmental Health, Department of Applied Medical Science, University of Southern Maine, Science Building, 96 Falmouth Street, Portland, ME 04103 (United States); Department of Radiation Oncology, Dana Farber Cancer Institute, 450 Brookline Ave., Boston, MA 02215 (United States); Liou, Louis [Department of Pathology, Boston University School of Medicine, 670 Albany St., Boston, MA 02118 (United States); Adam, Rosalyn M. [Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Wise, John Pierce Sr., E-mail: john.wise@louisville.edu [Wise Laboratory of Environmental and Genetic Toxicology, Maine Center for Toxicology and Environmental Health, Department of Applied Medical Science, University of Southern Maine, Science Building, 96 Falmouth Street, Portland, ME 04103 (United States)

    2016-04-01

    Numerous metals are well-known human bladder carcinogens. Despite the significant occupational and public health concern of metals and bladder cancer, the carcinogenic mechanisms remain largely unknown. Chromium, in particular, is a metal of concern as incidences of bladder cancer have been found elevated in chromate workers, and there is an increasing concern for patients with metal hip implants. However, the impact of hexavalent chromium (Cr(VI)) on bladder cells has not been studied. We compared chromate toxicity in two bladder cell lines; primary human urothelial cells and hTERT-immortalized human urothelial cells. Cr(VI) induced a concentration- and time-dependent increase in chromosome damage in both cell lines, with the hTERT-immortalized cells exhibiting more chromosome damage than the primary cells. Chronic exposure to Cr(VI) also induced a concentration-dependent increase in aneuploid metaphases in both cell lines which was not observed after a 24 h exposure. Aneuploidy induction was higher in the hTERT-immortalized cells. When we correct for uptake, Cr(VI) induces a similar amount of chromosome damage and aneuploidy suggesting that the differences in Cr(VI) sensitivity between the two cells lines were due to differences in uptake. The increase in chromosome instability after chronic chromate treatment suggests this may be a mechanism for chromate-induced bladder cancer, specifically, and may be a mechanism for metal-induced bladder cancer, in general. - Highlights: • Hexavalent chromium is genotoxic to human urothelial cells. • Hexavalent chromium induces aneuploidy in human urothelial cells. • hTERT-immortalized human urothelial cells model the effects seen in primary urothelial cells. • Hexavalent chromium has a strong likelihood of being carcinogenic for bladder tissue.

  15. Hexavalent chromate reduction during growth and by immobilized cells of arthrobacter sp. suk 1205

    International Nuclear Information System (INIS)

    Dey, S.; Paul, A.K.

    2017-01-01

    The chromate reducing actinomycetes, Arthrobacter sp. SUK 1205, isolated from chromite mine overburden of Odisha, India exhibited significant chromate reduction during growth with characteristic formation of pale green insoluble precipitate. Reduction of chromate increased with increase in inoculum density but the reduction potential declined as and when Cr(VI) concentration in the medium was increased. Chromate reducing efficiency was promoted when glycerol and glucose were used as electron donors and pH and temperature were maintained at 7.0 and 35 degree C, respectively. The reduction process was inhibited by several metal ions and metabolic inhibitors but not by Cu(II), Mn(II) and DNP. Among the matrices tested for whole cell immobilization, Ca-alginate immobilized whole cells were found to be most effective and were comparable with non-immobilized cells. Minimal salts (MS) medium was the most effective base for Cr(VI) reduction studies with immobilized cells. Under such conditions, the immobilized cells retained their enzymatic activity at least for 4 consecutive cycles indicating the potential of Arthrobacter sp. SUK 1205 in bioremediation of environmental chromium pollution. (author)

  16. Self-referenced axial chromatic dispersion measurement in multiphoton microscopy through 2-color THG imaging.

    Science.gov (United States)

    Du, Yu; Zhuang, Ziwei; He, Jiexing; Liu, Hongji; Qiu, Ping; Wang, Ke

    2018-05-16

    With tunable excitation light, multiphoton microscopy (MPM) is widely used for imaging biological structures at subcellular resolution. Axial chromatic dispersion, present in virtually every transmissive optical system including the multiphoton microscope, leads to focal (and the resultant image) plane separation. Here we demonstrate experimentally a technique to measure the axial chromatic dispersion in a multiphoton microscope, using simultaneous 2-color third-harmonic generation (THG) imaging excited by a 2-color soliton source with tunable wavelength separation. Our technique is self-referenced, eliminating potential measurement error when 1-color tunable excitation light is used which necessitates reciprocating motion of the mechanical translation stage. Using this technique, we demonstrate measured axial chromatic dispersion with 2 different objective lenses in a multiphoton microscope. Further measurement in a biological sample also indicates that this axial chromatic dispersion, in combination with 2-color imaging, may open up opportunity for simultaneous imaging of two different axial planes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  17. Synthesis of ZnO nanocoatings by decomposition of zinc acetate induced by electrons emitted by indium

    Energy Technology Data Exchange (ETDEWEB)

    Svoboda, Ladislav [Department of Chemistry, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Institute of Environmental Technologies, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Dvorský, Richard [Department of Physics, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Regional Materials Science and Technology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Praus, Petr, E-mail: petr.praus@vsb.cz [Department of Chemistry, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Institute of Environmental Technologies, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Matýsek, Dalibor [Institute of Geological Engineering, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic); Bednář, Jiří [Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, Ostrava 708 33 (Czech Republic)

    2016-12-01

    Graphical abstract: - Highlights: • Hexagonal ZnO was synthetized by the decomposition of zinc acetate under UV light. • Source of photogenerated electron was an indium plate. • ZnO nanocoatings were deposited on surface of silica nanoparticles. • Mean thickness of the ZnO nanocoatings was estimated by DLS at 13 nm. - Abstract: In this work, a new method for the synthesis of ZnO nanocoatings is presented. It was tested for the nanocoating of silica nanoparticles forming core/shell SiO{sub 2}/ZnO nanoparticles by the decomposition of zinc acetate in silica aqueous nanodispersions induced by electrons generated by a plate indium photocathode, which was irradiated with a UV Hg lamp with maximum intensity at the wavelength of 245 nm. The ZnO nanocoatings were examined by X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PLS), dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was found that ZnO of hexagonal structure formed nanocoatings with the mean thickness of 13 nm. The photocatalytic activity of ZnO nanocoatings was verified by the photocatalytic decomposition of methylene blue (MB). Such nanocoating procedure based on the electron-induced decomposition of suitable metal salts could be a promising method for various applications in nanotechnology.h.

  18. Influence of extracellular zinc on M1 microglial activation.

    Science.gov (United States)

    Higashi, Youichirou; Aratake, Takaaki; Shimizu, Shogo; Shimizu, Takahiro; Nakamura, Kumiko; Tsuda, Masayuki; Yawata, Toshio; Ueba, Tetuya; Saito, Motoaki

    2017-02-27

    Extracellular zinc, which is released from hippocampal neurons in response to brain ischaemia, triggers morphological changes in microglia. Under ischaemic conditions, microglia exhibit two opposite activation states (M1 and M2 activation), which may be further regulated by the microenvironment. We examined the role of extracellular zinc on M1 activation of microglia. Pre-treatment of microglia with 30-60 μM ZnCl 2 resulted in dose-dependent increases in interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNFα) secretion when M1 activation was induced by lipopolysaccharide administration. In contrast, the cell-permeable zinc chelator TPEN, the radical scavenger Trolox, and the P2X7 receptor antagonist A438079 suppressed the effects of zinc pre-treatment on microglia. Furthermore, endogenous zinc release was induced by cerebral ischaemia-reperfusion, resulting in increased expression of IL-1β, IL-6, TNFα, and the microglial M1 surface marker CD16/32, without hippocampal neuronal cell loss, in addition to impairments in object recognition memory. However, these effects were suppressed by the zinc chelator CaEDTA. These findings suggest that extracellular zinc may prime microglia to enhance production of pro-inflammatory cytokines via P2X7 receptor activation followed by reactive oxygen species generation in response to stimuli that trigger M1 activation, and that these inflammatory processes may result in deficits in object recognition memory.

  19. Objective assessment of chromatic and achromatic pattern adaptation reveals the temporal response properties of different visual pathways.

    Science.gov (United States)

    Robson, Anthony G; Kulikowski, Janus J

    2012-11-01

    The aim was to investigate the temporal response properties of magnocellular, parvocellular, and koniocellular visual pathways using increment/decrement changes in contrast to elicit visual evoked potentials (VEPs). Static achromatic and isoluminant chromatic gratings were generated on a monitor. Chromatic gratings were modulated along red/green (R/G) or subject-specific tritanopic confusion axes, established using a minimum distinct border criterion. Isoluminance was determined using minimum flicker photometry. Achromatic and chromatic VEPs were recorded to contrast increments and decrements of 0.1 or 0.2 superimposed on the static gratings (masking contrast 0-0.6). Achromatic increment/decrement changes in contrast evoked a percept of apparent motion when the spatial frequency was low; VEPs to such stimuli were positive in polarity and largely unaffected by high levels of static contrast, consistent with transient response mechanisms. VEPs to finer achromatic gratings showed marked attenuation as static contrast was increased. Chromatic VEPs to R/G or tritan chromatic contrast increments were of negative polarity and showed progressive attenuation as static contrast was increased, in keeping with increasing desensitization of the sustained responses of the color-opponent visual pathways. Chromatic contrast decrement VEPs were of positive polarity and less sensitive to pattern adaptation. The relative contribution of sustained/transient mechanisms to achromatic processing is spatial frequency dependent. Chromatic contrast increment VEPs reflect the sustained temporal response properties of parvocellular and koniocellular pathways. Cortical VEPs can provide an objective measure of pattern adaptation and can be used to probe the temporal response characteristics of different visual pathways.

  20. Zinc

    Science.gov (United States)

    ... Consumer Datos en español Health Professional Other Resources Zinc Fact Sheet for Consumers Have a question? Ask ... find out more about zinc? Disclaimer What is zinc and what does it do? Zinc is a ...

  1. Ameliorative effects of selenium and zinc

    African Journals Online (AJOL)

    Methidathion-induced hematological, biochemical and hepatohistological alterations in rat: Ameliorative effects of selenium and zinc. L Barkat, A Boumendjel, C Abdennour, MS Boulakoud, A El Feki, M Messarah ...

  2. Chromatic aberration compensation in numerical reconstruction of digital holograms by Fresnel-Bluestein propagation.

    Science.gov (United States)

    Hincapie, Diego; Velasquez, Daniel; Garcia-Sucerquia, Jorge

    2017-12-15

    In this Letter, we present a method for chromatic compensation in numerical reconstruction of digitally recorded holograms based on Fresnel-Bluestein propagation. The proposed technique is applied to correct the chromatic aberration that arises in the reconstruction of RGB holograms of both millimeter- and micrometer-sized objects. The results show the feasibility of this strategy to remove the wavelength dependence of the size of the numerically propagated wavefields.

  3. Soft solution synthesis and intense visible photoluminescence of lamellar zinc oxide hybrids

    International Nuclear Information System (INIS)

    Sağlam, Özge

    2013-01-01

    Graphical abstract: -- In this study, we demonstrate the synthesis of layered zinc oxide films intercalated with dodecyl sulphate ions by a simple soft solution process. The presence of potassium (K + ) and lithium (Li + ) ions in the precursor solution of layered zinc hydroxide resulted in lamellar hybrid zinc oxide films instead of layered zinc hydroxides. On the other hand, the addition of nickel phthalocyanine induces zinc hydroxide host layers which exhibit an intense blue emission. This is also promoted by K + and Li + ions

  4. Derivation of Human Chromatic Discrimination Ability from an Information-Theoretical Notion of Distance in Color Space.

    Science.gov (United States)

    da Fonseca, María; Samengo, Inés

    2016-12-01

    The accuracy with which humans detect chromatic differences varies throughout color space. For example, we are far more precise when discriminating two similar orange stimuli than two similar green stimuli. In order for two colors to be perceived as different, the neurons representing chromatic information must respond differently, and the difference must be larger than the trial-to-trial variability of the response to each separate color. Photoreceptors constitute the first stage in the processing of color information; many more stages are required before humans can consciously report whether two stimuli are perceived as chromatically distinguishable. Therefore, although photoreceptor absorption curves are expected to influence the accuracy of conscious discriminability, there is no reason to believe that they should suffice to explain it. Here we develop information-theoretical tools based on the Fisher metric that demonstrate that photoreceptor absorption properties explain about 87% of the variance of human color discrimination ability, as tested by previous behavioral experiments. In the context of this theory, the bottleneck in chromatic information processing is determined by photoreceptor absorption characteristics. Subsequent encoding stages modify only marginally the chromatic discriminability at the photoreceptor level.

  5. Obtention of zinc polymethacrylate via free radicals induced by gamma radiation

    International Nuclear Information System (INIS)

    Urena N, F.; Flores E, J.

    2000-01-01

    The objective of this work was to synthesise the monomer of zinc methacrylate and subsequently to carry out the polymerization reaction with the purpose to obtain the compound desired, the zinc polymethacrylate. For this it was used a gamma radiation source, 60 Co, as initiator of the polymerization reaction. (Author)

  6. Chromatic roots and limits of dense graphs

    Czech Academy of Sciences Publication Activity Database

    Csikvári, P.; Frenkel, P. E.; Hladký, Jan; Hubai, T.

    2017-01-01

    Roč. 340, č. 5 (2017), s. 1129-1135 ISSN 0012-365X EU Projects: European Commission(XE) 628974 - PAECIDM Institutional support: RVO:67985840 Keywords : chromatic root * graph limit * holomorphic moment Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.639, year: 2016 http://www.sciencedirect.com/science/article/pii/S0012365X16303661

  7. Low Maintenance Water Treatment for Heating and Cooling Systems: Review of Technologies and Guidelines for Implementation

    Science.gov (United States)

    2007-09-01

    to be used for advertising , publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of...form of scale con- trol for many years, but it has become fairly uncommon with the banning of the use of chromate as a corrosion inhibitor in open...D. Aranha. (1997). “A New Corrosion Inhibitor Program (Molybdate/Zinc) Replaces Successfully Chromate /Zinc, Under High Contamination Levels

  8. Metal Whiskers: A Discussion of Risks and Mitigation

    Science.gov (United States)

    2010-11-30

    efforts to investigate – Chromate conversion finishes DO NOT appear to stop whisker formation [4] S. Arnold, "Repressing the Growth of Tin Whiskers...November 30, 2010 Metal Whiskers 10 Examples of Metal Whiskers Zinc-Plated Steel Bus Rail with Yellow Chromate Conversion Finish Zinc whiskers grew...Metal Whiskers 11 Examples of Metal Whiskers Tin-Plated D-Sub Connector Shell Connector Advertised as “RoHS Compliant” November 30, 2010 Metal

  9. Hepatic ZIP14-mediated zinc transport is required for adaptation to endoplasmic reticulum stress.

    Science.gov (United States)

    Kim, Min-Hyun; Aydemir, Tolunay B; Kim, Jinhee; Cousins, Robert J

    2017-07-18

    Extensive endoplasmic reticulum (ER) stress damages the liver, causing apoptosis and steatosis despite the activation of the unfolded protein response (UPR). Restriction of zinc from cells can induce ER stress, indicating that zinc is essential to maintain normal ER function. However, a role for zinc during hepatic ER stress is largely unknown despite important roles in metabolic disorders, including obesity and nonalcoholic liver disease. We have explored a role for the metal transporter ZIP14 during pharmacologically and high-fat diet-induced ER stress using Zip14 -/- (KO) mice, which exhibit impaired hepatic zinc uptake. Here, we report that ZIP14-mediated hepatic zinc uptake is critical for adaptation to ER stress, preventing sustained apoptosis and steatosis. Impaired hepatic zinc uptake in Zip14 KO mice during ER stress coincides with greater expression of proapoptotic proteins. ER stress-induced Zip14 KO mice show greater levels of hepatic steatosis due to higher expression of genes involved in de novo fatty acid synthesis, which are suppressed in ER stress-induced WT mice. During ER stress, the UPR-activated transcription factors ATF4 and ATF6α transcriptionally up-regulate Zip14 expression. We propose ZIP14 mediates zinc transport into hepatocytes to inhibit protein-tyrosine phosphatase 1B (PTP1B) activity, which acts to suppress apoptosis and steatosis associated with hepatic ER stress. Zip14 KO mice showed greater hepatic PTP1B activity during ER stress. These results show the importance of zinc trafficking and functional ZIP14 transporter activity for adaptation to ER stress associated with chronic metabolic disorders.

  10. METHOD OF SOFTWARE-BASED COMPENSATION OF TECHNOLOGICAL VARIATION IN CHROMATICITY COORDINATES OF LCD PANELS

    Directory of Open Access Journals (Sweden)

    I. O. Zharinov

    2015-05-01

    Full Text Available Subject of research. The problem of software-based compensation of technological variation in chromaticity coordinates of liquid crystal panels is considered. A method of software-based compensation of technological variation in chromaticity coordinates is proposed. The method provides the color reproduction characteristics of the series-produced samples on-board indication equipment corresponding to the sample equipment, which is taken as the standard. Method. Mathematical calculation of the profile is performed for the given model of the liquid crystal panel. The coefficients that correspond to the typical values of the chromaticity coordinates for the vertices of the triangle color coverage constitute a reference mathematical model of the plate LCD panel from a specific manufacturer. At the stage of incoming inspection the sample of the liquid crystal panel, that is to be implemented within indication equipment, is mounted on the lighting test unit, where Nokia-Test control is provided by the formation of the RGB codes for display the image of a homogeneous field in the red, green, blue and white. The measurement of the (x,y-chromaticity coordinates in red, green, blue and white colors is performed using a colorimeter with the known value of absolute error. Instead of using lighting equipment, such measurements may be carried out immediately on the sample indication equipment during customizing procedure. The measured values are used to calculate individual LCD-panel profile coefficients through the use of Grassman's transformation, establishing mutual relations between the XYZ-color coordinates and RGB codes to be used for displaying the image on the liquid crystal panel. The obtained coefficients are to be set into the memory of the graphics controller together with the functional software and then used for image displaying. Main results. The efficiency of the proposed method of software-based compensation for technological variation of

  11. Chromium, Nickel and Zinc Induced Histopathological Alterations in ...

    African Journals Online (AJOL)

    Michael Horsfall

    fish, Labeo rohita to chlorides of chromium, nickel and zinc for 30 days. However ... toxicants such as salts of heavy metals, acids, organic matter ... nutritional supply becomes excessive. ... action), petrochemicals, and fertilizers and in steam.

  12. On threshold mechanisms for achromatic and chromatic vision

    NARCIS (Netherlands)

    Bouman, M.A.; Walraven, P.L.

    1972-01-01

    On the basis of measurements of the achromatic zone for red light in the fovea and for green light in the periphery, a discussion is given on the possible difference in threshold mechanisms for the achromatic (scotopic) and chromatic (photopic) retinal systems. A specific suggestion for this

  13. Mechanisms of inhibition of zinc-finger transcription factors by selenium compounds ebselen and selenite.

    Science.gov (United States)

    Larabee, Jason L; Hocker, James R; Hanas, Jay S

    2009-03-01

    The anti-inflammatory selenium compounds, ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) and selenite, were found to alter the DNA binding mechanisms and structures of cysteine-rich zinc-finger transcription factors. As assayed by DNase I protection, DNA binding by TFIIIA (transcription factor IIIA, prototypical Cys(2)His(2) zinc finger protein), was inhibited by micromolar amounts of ebselen. In a gel shift assay, ebselen inhibited the Cys(2)His(2) zinc finger-containing DNA binding domain (DBD) of the NF-kappaB mediated transcription factor Sp1. Ebselen also inhibited DNA binding by the p50 subunit of the pro-inflammatory Cys-containing NF-kappaB transcription factor. Electrospray ionization mass spectrometry (ESI-MS) was utilized to elucidate mechanisms of chemical interaction between ebselen and a zinc-bound Cys(2)His(2) zinc finger polypeptide modeled after the third finger of Sp1 (Sp1-3). Exposing Sp1-3 to micromolar amounts of ebselen resulted in Zn(2+) release from this peptide and the formation of a disulfide bond by oxidation of zinc finger SH groups, the likely mechanism for DNA binding inhibition. Selenite was shown by ESI-MS to also eject zinc from Sp1-3 as well as induce disulfide bond formation through SH oxidation. The selenite-dependent inhibition/oxidation mechanism differed from that of ebselen by inducing the formation of a stable selenotrisulfide bond. Selenite-induced selenotrisulfide formation was dependent upon the structure of the Cys(2)His(2) zinc finger as alteration in the finger structure enhanced this reaction as well as selenite-dependent zinc release. Ebselen and selenite-dependent inhibition/oxidation of Cys-rich zinc finger proteins, with concomitant release of zinc and finger structural changes, points to mechanisms at the atomic and protein level for selenium-induced alterations in Cys-rich proteins, and possible amelioration of certain inflammatory, neurodegenerative, and oncogenic responses.

  14. Ultrasound-assisted synthesis of zinc molybdate nanocrystals and molybdate-doped epoxy/PDMS nanocomposite coatings for Mg alloy protection.

    Science.gov (United States)

    Eduok, Ubong; Szpunar, Jerzy

    2018-06-01

    Zinc molybdate (ZM) is a safer anticorrosive additive for cooling systems when compared with chromates and lead salts, due to its insolubility in aqueous media. For most molybdate pigments, their molybdate anion (MoO 4 -2 ) acts as an anionic inhibitor and its passivation capacity is comparable with chromate anion (CrO 4 -2 ). To alleviate the environmental concerns involving chromates-based industrial protective coatings, we have proposed new alternative in this work. We have synthesized ZM nanocrystals via ultrasound-assisted process and encapsulated them within an epoxy/PDMS coating towards corrosion protection. The surface morphology and mechanical properties of these ZM doped epoxy/PDMS nanocomposite coatings is exhaustively discussed to show the effect of ZM content on protective properties. The presence of ZM nanocrystals significantly contributed to the corrosion barrier performance of the coating while the amount of ZM nanocrystals needed to prepare an epoxy coating with optimum barrier performance was established. Beyond 2 wt% ZM concentration, the siloxane-structured epoxy coating network became saturated with ZM pigments. This further broadened inherent pores channels, leading to the percolation of corrosion chloride ions through the coating. SEM evidence has revealed proof of surface delamination on ZM3 coating. A model mechanism of corrosion resistance has been proposed for ZM doped epoxy/PDMS nanocomposite coatings from exhaustive surface morphological investigations and evidence. This coating matrix may have emerging applications in cooling systems as anticorrosive surface paints as well as create an avenue for environmental corrosion remediation. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Chromatic discrimination: differential contributions from two adapting fields

    Science.gov (United States)

    Cao, Dingcai; Lu, Yolanda H.

    2012-01-01

    To test whether a retinal or cortical mechanism sums contributions from two adapting fields to chromatic discrimination, L/M discrimination was measured with a test annulus surrounded by an inner circular field and an outer rectangular field. A retinal summation mechanism predicted that the discrimination pattern would not change with a change in the fixation location. Therefore, the fixation was set either in the inner or the outer field in two experiments. When one of the adapting fields was “red” and the other was “green,” the adapting field where the observer fixated always had a stronger influence on chromatic discrimination. However, when one adapting field was “white” and the other was red or green, the white field always weighted more heavily than the other adapting field in determining discrimination thresholds, whether the white field or the fixation was in the inner or outer adapting field. These results suggest that a cortical mechanism determines the relative contributions from different adapting fields. PMID:22330364

  16. Towards Bio-Inspired Chromatic Behaviours in Surveillance Robots

    Directory of Open Access Journals (Sweden)

    Sampath Kumar Karutaa Gnaniar

    2016-09-01

    Full Text Available The field of Robotics is ever growing at the same time as posing enormous challenges. Numerous works has been done in biologically inspired robotics emulating models, systems and elements of nature for the purpose of solving traditional robotics problems. Chromatic behaviours are abundant in nature across a variety of living species to achieve camouflage, signaling, and temperature regulation. The ability of these creatures to successfully blend in with their environment and communicate by changing their colour is the fundamental inspiration for our research work. In this paper, we present dwarf chameleon inspired chromatic behaviour in the context of an autonomous surveillance robot, “PACHONDHI”. In our experiments, we successfully validated the ability of the robot to autonomously change its colour in relation to the terrain that it is traversing for maximizing detectability to friendly security agents and minimizing exposure to hostile agents, as well as to communicate with fellow cooperating robots.

  17. Comparison of CIE chromaticity values

    CSIR Research Space (South Africa)

    Van Tonder, N

    1999-02-02

    Full Text Available matter #1999 Elsevier Science B.V. All rights reserved. PII: S0003-2670(98)00526-1 an opal glass white standard. Furthermore, the x and y CIE chromaticity values had to be calculated under the conditions of illuminants A, C and D65 with a 28 observer. 2... to the South African national measuring standards of light by an opal glass re?ectance standard (NPL calibration number AU87) calibrated by the National Physical Laboratory, UK (NPL). Re?ectance measurements were taken at three different positions on each...

  18. Forcing clique immersions through chromatic number

    OpenAIRE

    Gauthier, Gregory; Le, Tien-Nam; Wollan, Paul

    2017-01-01

    Building on recent work of Dvo\\v{r}\\'ak and Yepremyan, we show that every simple graph of minimum degree $7t+7$ contains $K_t$ as an immersion and that every graph with chromatic number at least $3.54t + 4$ contains $K_t$ as an immersion. We also show that every graph on $n$ vertices with no stable set of size three contains $K_{2\\lfloor n/5 \\rfloor}$ as an immersion.

  19. Chromaticity decay due to superconducting dipoles on the injection plateau of the Large Hadron Collider

    Directory of Open Access Journals (Sweden)

    N. Aquilina

    2012-03-01

    Full Text Available It is well known that in a superconducting accelerator a significant chromaticity drift can be induced by the decay of the sextupolar component of the main dipoles. In this paper we give a brief overview of what was expected for the Large Hadron Collider (LHC on the grounds of magnetic measurements of individual dipoles carried out during the production. According to this analysis, the decay time constants were of the order of 200 s: since the injection in the LHC starts at least 30 minutes after the magnets are at constant current, the dynamic correction of this effect was not considered to be necessary. The first beam measurements of chromaticity showed significant decay even after a few hours. For this reason, a dynamic correction of decay on the injection plateau was implemented based on beam measurements. This means that during the injection plateau the sextupole correctors are powered with a varying current to cancel out the decay of the dipoles. This strategy has been implemented successfully. A similar phenomenon has been observed for the dependence of the decay amplitude on the powering history of the dipoles: according to magnetic measurements, also in this case time constants are of the order of 200 s and therefore no difference is expected between a one hour or a ten hours flattop. On the other hand, the beam measurements show a significant change of decay for these two conditions. For the moment there is no clue of the origin of these discrepancies. We give a complete overview of the two effects, and the modifications that have been done to the field model parameters to be able to obtain a final chromaticity correction within a few units.

  20. Reduction of chromate from electroplating wastewater from pH 1 to 2 using fluidized zero valent iron process

    International Nuclear Information System (INIS)

    Chen, S.-S.; Cheng, C.-Y.; Li, C.-W.; Chai, P.-H.; Chang, Y.-M.

    2007-01-01

    Fluidized zero valent iron (ZVI) process was conducted to reduce hexavalent chromium (chromate, CrO 4 2- ) to trivalent chromium (Cr 3+ ) from electroplating wastewater due to the following reasons: (1) Extremely low pH (1-2) for the electroplating wastewater favoring the ZVI reaction. (2) The ferric ion, produced from the reaction of Cr(VI) and ZVI, can act as a coagulant to assist the precipitation of Cr(OH) 3(s) to save the coagulant cost. (3) Higher ZVI utilization for fluidized process due to abrasive motion of the ZVI. For influent chromate concentration of 418 mg/L as Cr 6+ , pH 2 and ZVI dosage of 3 g (41 g/L), chromate removal was only 29% with hydraulic detention time (HRT) of 1.2 min, but was increased to 99.9% by either increasing HRT to 5.6 min or adjusting pH to 1.5. For iron species at pH 2 and HRT of 1.2 min, Fe 3+ was more thermodynamically stable since oxidizing agent chromate was present. However, if pH was adjusted to 1.5 or 1, where chromate was completely removed, high Fe 2+ but very low Fe 3+ was present. It can be explained that ZVI reacted with chromate to produce Fe 2+ first and the presence of chromate would keep converting Fe 2+ to Fe 3+ . Therefore, Fe 2+ is an indicator for complete reduction from Cr(VI) to Cr(III). X-ray diffraction (XRD) was conducted to exam the remained species at pH 2. ZVI, iron oxide and iron sulfide were observed, indicating the formation of iron oxide or iron sulfide could stop the chromate reduction reaction

  1. The role of hexafluorozirconate in the formation of chromate conversion coatings on aluminum alloys

    International Nuclear Information System (INIS)

    Chidambaram, Devicharan; Clayton, Clive R.; Halada, Gary P.

    2006-01-01

    Aluminum based surfaces are routinely coated with a chromate based layer that provides unparalleled corrosion protection. Widely used conversion coating treatment formulations contain hexafluorozirconate as a major constituent besides chromate, ferricyanide, fluoride, and fluoborate. The function of hexafluorozirconate is the subject of this study as its function is still largely unknown. Hydrophobicity, surface morphology, and the chemistry of the surface, resulting from treatment with hexafluorozirconate, were studied using contact angle measurements, scanning electron microscopy, and energy dispersive spectroscopy, respectively. X-ray photoelectron spectroscopy was extensively utilized to determine the chemistry of the surface resulting from the hexafluorozirconate pretreatment. Our results indicate that fluoride ion containing hexafluorozirconate complex does not attack the oxide film in a manner that uncomplexed simple fluoride ion does. Hexafluorozirconate is involved in the formation of an Al-Zr-O-F based hydrated layer that increases the hydrophilicity of the surface, activates the surface, and lowers the corrosion resistance. These factors enhance the interaction of chromate with the alloy surface to result in the formation of a uniform conversion coating. Based on these results, a new model has been proposed for the formation of chromate conversion coatings

  2. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models.

    Science.gov (United States)

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-11

    In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3 mm of pupil diameter and from 0 to out-of-focus blur were collected and graphed. MTF values, measured at 555 nm of monochromatic light under each spatial frequency, were significantly higher than the values measured at 470 to 650 nm of polychromatic light. The influences of chromatic aberration on MTF values decreased with the increase in IOL diopter when the spatial frequency was ≤12 c/d, while increased effects were observed when the spatial frequency was ≥15 c/d. The MTF values of each IOL eye model were significantly lower than the MTF values of the Liou-Brennan eye models when measured at 555 nm of monochromatic light and at 470 to 650 nm of polychromatic light. The MTF values were also found to be increased with the increase in IOL diopter. With higher diopters of IOLs, the central thickness increased accordingly, which could have created increased chromatic aberration and decreased the retinal image quality. To improve the postoperative visual quality, IOLs with lower chromatic aberration should be selected for patients with short axial lengths.

  3. Chromatic detection from cone photoreceptors to V1 neurons to behavior in rhesus monkeys.

    Science.gov (United States)

    Hass, Charles A; Angueyra, Juan M; Lindbloom-Brown, Zachary; Rieke, Fred; Horwitz, Gregory D

    2015-01-01

    Chromatic sensitivity cannot exceed limits set by noise in the cone photoreceptors. To determine how close neurophysiological and psychophysical chromatic sensitivity come to these limits, we developed a parameter-free model of stimulus encoding in the cone outer segments, and we compared the sensitivity of the model to the psychophysical sensitivity of monkeys performing a detection task and to the sensitivity of individual V1 neurons. Modeled cones had a temporal impulse response and a noise power spectrum that were derived from in vitro recordings of macaque cones, and V1 recordings were made during performance of the detection task. The sensitivity of the simulated cone mosaic, the V1 neurons, and the monkeys were tightly yoked for low-spatiotemporal-frequency isoluminant modulations, indicating high-fidelity signal transmission for this class of stimuli. Under the conditions of our experiments and the assumptions for our model, the signal-to-noise ratio for these stimuli dropped by a factor of ∼3 between the cones and perception. Populations of weakly correlated V1 neurons narrowly exceeded the monkeys' chromatic sensitivity but fell well short of the cones' chromatic sensitivity, suggesting that most of the behavior-limiting noise lies between the cone outer segments and the output of V1. The sensitivity gap between the cones and behavior for achromatic stimuli was larger than for chromatic stimuli, indicating greater postreceptoral noise. The cone mosaic model provides a means to compare visual sensitivity across disparate stimuli and to identify sources of noise that limit visual sensitivity.

  4. Laboratory evaluation of the potential for in situ treatment of chromate-contaminated groundwater by chemical precipitation

    International Nuclear Information System (INIS)

    Thornton, E.C.; Beck, M.A.; Jurgensmeier, C.A.

    1995-03-01

    The objective of this paper is to present the results of a series of small-scale batch tests performed to assess the effectiveness of chemical precipitation in the remediation of chromate-contaminated groundwater. These tests involved treatment of chromate solutions with ferrous and sulfide ions. In addition, tests were conducted that involved treatment of mixtures of chromate-contaminated groundwater and uncontaminated soil with the ferrous ion. A combination of ferrous sulfate and sodium sulfide was also tested in the groundwater treatment tests, since this approach has been shown to be an efficient method for treating electroplating wastewaters

  5. Nutrition intervention strategies to combat zinc deficiency in developing countries.

    Science.gov (United States)

    Gibson, R S; Ferguson, E L

    1998-06-01

    Widespread zinc deficiency is likely to exist in developing countries where staple diets are predominantly plant based and intakes of animal tissues are low. The severe negative consequences of zinc deficiency on human health in developing countries, however, have only recently been recognized. An integrated approach employing targeted supplementation, fortification and dietary strategies must be used to maximize the likelihood of eliminating zinc deficiency at a national level in developing countries. Supplementation is appropriate only for populations whose zinc status must be improved over a relatively short time period, and when requirements cannot be met from habitual dietary sources. As well, the health system must be capable of providing consistent supply, distribution, delivery and consumption of the zinc supplement to the targeted groups. Uncertainties still exist about the type, frequency, and level of supplemental zinc required for prevention and treatment of zinc deficiency. Salts that are readily absorbed and at levels that will not induce antagonistic nutrient interactions must be used. At a national level, fortification with multiple micronutrients could be a cost effective method for improving micronutrient status, including zinc, provided that a suitable food vehicle which is centrally processed is available. Alternatively, fortification could be targeted for certain high risk groups (e.g. complementary foods for infants). Efforts should be made to develop protected fortificants for zinc, so that potent inhibitors of zinc absorption (e.g. phytate) present either in the food vehicle and/or indigenous meals do not compromise zinc absorption. Fortification does not require any changes in the existing food beliefs and practices for the consumer and, unlike supplementation, does not impose a burden on the health sector. A quality assurance programme is required, however, to ensure the quality of the fortified food product from production to consumption

  6. Chromatic Titanium Photoanode for Dye-Sensitized Solar Cells under Rear Illumination.

    Science.gov (United States)

    Huang, Chih-Hsiang; Chen, Yu-Wen; Chen, Chih-Ming

    2018-01-24

    Titanium (Ti) has high potential in many practical applications such as biomedicine, architecture, aviation, and energy. In this study, we demonstrate an innovative application of dye-sensitized solar cells (DSSCs) based on Ti photoanodes that can be integrated into the roof engineering of large-scale architectures. A chromatic Ti foil produced by anodizing oxidation (coloring) technology is an attractive roof material for large-scale architecture, showing a colorful appearance due to the formation of a reflective TiO 2 thin layer on both surfaces of Ti. The DSSC is fabricated on the backside of the chromatic Ti foil using the Ti foil as the working electrode, and this roof-DSSC hybrid configuration can be designed as an energy harvesting device for indoor artificial lighting. Our results show that the facet-textured TiO 2 layer on the chromatic Ti foil not only improves the optical reflectance for better light utilization but also effectively suppresses the charge recombination for better electron collection. The power conversion efficiency of the roof-DSSC hybrid system is improved by 30-40% with a main contribution from an improvement of short-circuit current density under standard 1 sun and dim-light (600-1000 lx) illumination.

  7. Rising intracellular zinc by membrane depolarization and glucose in insulin-secreting clonal HIT-T15 beta cells.

    Science.gov (United States)

    Slepchenko, Kira G; Li, Yang V

    2012-01-01

    Zinc (Zn(2+)) appears to be intimately involved in insulin metabolism since insulin secretion is correlated with zinc secretion in response to glucose stimulation, but little is known about the regulation of zinc homeostasis in pancreatic beta-cells. This study set out to identify the intracellular zinc transient by imaging free cytosolic zinc in HIT-T15 beta-cells with fluorescent zinc indicators. We observed that membrane depolarization by KCl (30-60 mM) was able to induce a rapid increase in cytosolic concentration of zinc. Multiple zinc transients of similar magnitude were elicited during repeated stimulations. The amplitude of zinc responses was not affected by the removal of extracellular calcium or zinc. However, the half-time of the rising slope was significantly slower after removing extracellular zinc with zinc chelator CaEDTA, suggesting that extracellular zinc affect the initial rising phase of zinc response. Glucose (10 mM) induced substantial and progressive increases in intracellular zinc concentration in a similar way as KCl, with variation in the onset and the duration of zinc mobilization. It is known that the depolarization of beta-cell membrane is coupled with the secretion of insulin. Rising intracellular zinc concentration may act as a critical signaling factor in insulin metabolism of pancreatic beta-cells.

  8. Localized frustration and binding-induced conformational change in recognition of 5S RNA by TFIIIA zinc finger.

    Science.gov (United States)

    Tan, Cheng; Li, Wenfei; Wang, Wei

    2013-12-19

    Protein TFIIIA is composed of nine tandemly arranged Cys2His2 zinc fingers. It can bind either to the 5S RNA gene as a transcription factor or to the 5S RNA transcript as a chaperone. Although structural and biochemical data provided valuable information on the recognition between the TFIIIIA and the 5S DNA/RNA, the involved conformational motions and energetic factors contributing to the binding affinity and specificity remain unclear. In this work, we conducted MD simulations and MM/GBSA calculations to investigate the binding-induced conformational changes in the recognition of the 5S RNA by the central three zinc fingers of TFIIIA and the energetic factors that influence the binding affinity and specificity at an atomistic level. Our results revealed drastic interdomain conformational changes between these three zinc fingers, involving the exposure/burial of several crucial DNA/RNA binding residues, which can be related to the competition between DNA and RNA for the binding of TFIIIA. We also showed that the specific recognition between finger 4/finger 6 and the 5S RNA introduces frustrations to the nonspecific interactions between finger 5 and the 5S RNA, which may be important to achieve optimal binding affinity and specificity.

  9. Serum zinc levels in gestational diabetes

    Directory of Open Access Journals (Sweden)

    Rahimi Sharbaf F

    2008-12-01

    Full Text Available "nBackground: Maternal zinc deficiency during pregnancy has been related to adverse pregnancy outcomes. Most studies in which pregnant women have been supplemented with zinc to examine its effects on the outcome of the pregnancy have been carried out in industrialized countries and the results have been inconclusive. It has been shown that women with gestational diabetes (GDM have lower serum zinc levels than healthy pregnant women, and higher rates of macrosomia. Zinc is required for normal glucose metabolism, and strengthens the insulin-induced transportation of glucose into cells by its effect on the insulin signaling pathway. The purpose of this study was to assess the serum zinc levels of GDM patients and evaluate the effect of zinc supplementation. "nMethods: In the first stage of this prospective controlled study, we enrolled 70 women who were 24-28 weeks pregnant at the Prenatal Care Center of Mirza Kochak Khan Hospital, Tehran, Iran. The serum zinc level of each subject was determined. In the second stage, among these 70 subjects, the diabetics receiving insulin were divided into two groups, only one of which received a zinc supplement and the other group was the control group. Birth weight of neonates and insulin dosages were recorded. "nResults: The mean serum zinc level in the GDM group was lower than that of the control group (94.83 vs. 103.49mg/dl, respectively and the mean birth weight of neonates from the GDM women who received the zinc supplement was lower than that of the control group (3849g vs. 4136g. The rate of macrosomia was lower in the zinc supplemented group (20% vs. 53%. The mean of increase of insulin after receiving the zinc supplement was lower (8.4u vs. 13.53. "nConclusion: Maternal insulin resistance is associated with the accumulation of maternal fat tissue during early stages of pregnancy and greater fetoplacental nutrient availability in later stages, when 70% of fetal growth occurs, resulting in macrosomia. In

  10. Dietary phytate, zinc and hidden zinc deficiency.

    Science.gov (United States)

    Sandstead, Harold H; Freeland-Graves, Jeanne H

    2014-10-01

    Epidemiological data suggest at least one in five humans are at risk of zinc deficiency. This is in large part because the phytate in cereals and legumes has not been removed during food preparation. Phytate, a potent indigestible ligand for zinc prevents it's absorption. Without knowledge of the frequency of consumption of foods rich in phytate, and foods rich in bioavailable zinc, the recognition of zinc deficiency early in the illness may be difficult. Plasma zinc is insensitive to early zinc deficiency. Serum ferritin concentration≤20μg/L is a potential indirect biomarker. Early effects of zinc deficiency are chemical, functional and may be "hidden". The clinical problem is illustrated by 2 studies that involved US Mexican-American children, and US premenopausal women. The children were consuming home diets that included traditional foods high in phytate. The premenopausal women were not eating red meat on a regular basis, and their consumption of phytate was mainly from bran breakfast cereals. In both studies the presence of zinc deficiency was proven by functional responses to controlled zinc treatment. In the children lean-mass, reasoning, and immunity were significantly affected. In the women memory, reasoning, and eye-hand coordination were significantly affected. A screening self-administered food frequency questionnaire for office might help caregiver's identify patients at risk of zinc deficiency. Copyright © 2014 Elsevier GmbH. All rights reserved.

  11. The Emerging Role of Zinc in the Pathogenesis of Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Bo Young Choi

    2017-09-01

    Full Text Available Our lab has previously demonstrated that multiple sclerosis-induced spinal cord white matter damage and motor deficits are mediated by the pathological disruption of zinc homeostasis. Abnormal vesicular zinc release and intracellular zinc accumulation may mediate several steps in the pathophysiological processes of multiple sclerosis (MS, such as matrix metallopeptidase 9 (MMP-9 activation, blood-brain barrier (BBB disruption, and subsequent immune cell infiltration from peripheral systems. Oral administration of a zinc chelator decreased BBB disruption, immune cell infiltration, and spinal white matter myelin destruction. Therefore, we hypothesized that zinc released into the extracellular space during MS progression is involved in destruction of the myelin sheath in spinal cord white mater and in generation of motor deficits. To confirm our previous study, we employed zinc transporter 3 (ZnT3 knockout mice to test whether vesicular zinc depletion shows protective effects on multiple sclerosis-induced white matter damage and motor deficits. ZnT3 gene deletion profoundly reduced the daily clinical score of experimental autoimmune encephalomyelitis (EAE by suppression of inflammation and demyelination in the spinal cord. ZnT3 gene deletion also remarkably inhibited formation of multiple sclerosis-associated aberrant synaptic zinc patches, MMP-9 activation, and BBB disruption. These two studies strongly support our hypothesis that zinc release from presynaptic terminals may be involved in multiple sclerosis pathogenesis. Further studies will no doubt continue to add mechanistic detail to this process and with luck, clarify how these observations may lead to development of novel therapeutic approaches for the treatment of multiple sclerosis.

  12. The Emerging Role of Zinc in the Pathogenesis of Multiple Sclerosis.

    Science.gov (United States)

    Choi, Bo Young; Jung, Jong Won; Suh, Sang Won

    2017-09-28

    Our lab has previously demonstrated that multiple sclerosis-induced spinal cord white matter damage and motor deficits are mediated by the pathological disruption of zinc homeostasis. Abnormal vesicular zinc release and intracellular zinc accumulation may mediate several steps in the pathophysiological processes of multiple sclerosis (MS), such as matrix metallopeptidase 9 (MMP-9) activation, blood-brain barrier (BBB) disruption, and subsequent immune cell infiltration from peripheral systems. Oral administration of a zinc chelator decreased BBB disruption, immune cell infiltration, and spinal white matter myelin destruction. Therefore, we hypothesized that zinc released into the extracellular space during MS progression is involved in destruction of the myelin sheath in spinal cord white mater and in generation of motor deficits. To confirm our previous study, we employed zinc transporter 3 ( ZnT3 ) knockout mice to test whether vesicular zinc depletion shows protective effects on multiple sclerosis-induced white matter damage and motor deficits. ZnT3 gene deletion profoundly reduced the daily clinical score of experimental autoimmune encephalomyelitis (EAE) by suppression of inflammation and demyelination in the spinal cord. ZnT3 gene deletion also remarkably inhibited formation of multiple sclerosis-associated aberrant synaptic zinc patches, MMP-9 activation, and BBB disruption. These two studies strongly support our hypothesis that zinc release from presynaptic terminals may be involved in multiple sclerosis pathogenesis. Further studies will no doubt continue to add mechanistic detail to this process and with luck, clarify how these observations may lead to development of novel therapeutic approaches for the treatment of multiple sclerosis.

  13. Zinc and Regulation of Inflammatory Cytokines: Implications for Cardiometabolic Disease

    Science.gov (United States)

    Foster, Meika; Samman, Samir

    2012-01-01

    In atherosclerosis and diabetes mellitus, the concomitant presence of low-grade systemic inflammation and mild zinc deficiency highlights a role for zinc nutrition in the management of chronic disease. This review aims to evaluate the literature that reports on the interactions of zinc and cytokines. In humans, inflammatory cytokines have been shown both to up- and down-regulate the expression of specific cellular zinc transporters in response to an increased demand for zinc in inflammatory conditions. The acute phase response includes a rapid decline in the plasma zinc concentration as a result of the redistribution of zinc into cellular compartments. Zinc deficiency influences the generation of cytokines, including IL-1β, IL-2, IL-6, and TNF-α, and in response to zinc supplementation plasma cytokines exhibit a dose-dependent response. The mechanism of action may reflect the ability of zinc to either induce or inhibit the activation of NF-κB. Confounders in understanding the zinc-cytokine relationship on the basis of in vitro experimentation include methodological issues such as the cell type and the means of activating cells in culture. Impaired zinc homeostasis and chronic inflammation feature prominently in a number of cardiometabolic diseases. Given the high prevalence of zinc deficiency and chronic disease globally, the interplay of zinc and inflammation warrants further examination. PMID:22852057

  14. Fluctuations in the prevalence of chromate allergy in Denmark and exposure to chrome-tanned leather

    DEFF Research Database (Denmark)

    Carøe, Caroline; Andersen, Klaus E; Thyssen, Jacob P

    2010-01-01

    A recent Danish study showed a significant increase in the prevalence of chromate contact allergy after the mid-1990s, probably as a result of exposure to leather products.......A recent Danish study showed a significant increase in the prevalence of chromate contact allergy after the mid-1990s, probably as a result of exposure to leather products....

  15. A lateral chromatic aberration correction system for ultrahigh-definition color video camera

    Science.gov (United States)

    Yamashita, Takayuki; Shimamoto, Hiroshi; Funatsu, Ryohei; Mitani, Kohji; Nojiri, Yuji

    2006-02-01

    We have developed color camera for an 8k x 4k-pixel ultrahigh-definition video system, which is called Super Hi- Vision, with a 5x zoom lens and a signal-processing system incorporating a function for real-time lateral chromatic aberration correction. The chromatic aberration of the lens degrades color image resolution. So in order to develop a compact zoom lens consistent with ultrahigh-resolution characteristics, we incorporated a real-time correction function in the signal-processing system. The signal-processing system has eight memory tables to store the correction data at eight focal length points on the blue and red channels. When the focal length data is inputted from the lens control units, the relevant correction data are interpolated from two of eights correction data tables. This system performs geometrical conversion on both channels using this correction data. This paper describes that the correction function can successfully reduce the lateral chromatic aberration, to an amount small enough to ensure the desired image resolution was achieved over the entire range of the lens in real time.

  16. Zinc-induced hemolytic anemia caused by ingestion of pennies by a pup

    International Nuclear Information System (INIS)

    Latimer, K.S.; Jain, A.V.; Inglesby, H.B.; Clarkson, W.D.; Johnson, G.B.

    1989-01-01

    A 4-month-old Pomeranian pup was examined because of anorexia, salivation, and persistent vomiting. Initial laboratory testing revealed marked hemolytic anemia with spherocytosis. Survey abdominal radiography revealed 4 metal objects which, when removed by gastrotomy, were identified as pennies. Of 4 pennies, 3 were minted since 1983 and were heavily pitted over the surface and rim. Partially digested pennies were composed of a copper-plated high zinc concentration alloy. Further laboratory testing indicated a marked increase in serum zinc concentration in the pup (28.8 mg/L), confirming metal toxicosis. Serum zinc concentrations decreased during recovery

  17. [Chromaticity and optical spectrum colorimetry of the tongue color in different syndromes of primary hepatic carcinoma].

    Science.gov (United States)

    Xu, Ying; Zeng, Chang-chun; Cai, Xiu-yu; Guo, Rong-ping; Nie, Guang; Jin, Ying

    2012-11-01

    In this study, the optical data of tongue color of different syndromes in primary hepatic carcinoma (PHC) were detected by optical spectrum colorimetry, and the chromaticity of tongue color was compared and analyzed. The tongue color characteristics of different syndromes in PHC and the relationship between different syndromes and tongue color were also investigated. Tongue color data from 133 eligible PHC patients were collected by optical spectrum colorimetry and the patients were divided into 4 syndrome groups according to their clinical features. The syndrome groups were liver depression and spleen deficiency (LDSD), accumulation of damp-heat (ADH), deficiency of liver and kidney yin (DLKY), and qi stagnation and blood stasis (QSBS). The variation characteristics of chromaticity coordinates, dominant wavelength, excitation purity and the distribution in the International Commission on Illumination (CIE) LAB uniform color space were measured. At the same time, the differences of overall chromatism, clarity, chroma, saturation and hue were also calculated and analyzed. PHC patients in different syndrome groups exhibited differences in chromaticity coordinates. The dominant wavelength of QSBS was distinctly different from that of the other 3 syndromes. Excitation purity in the syndromes of LDSD, ADH and DLKY showed gradual increases (Pcolorimetry technology. Different syndromes in PHC exhibit distinct chromatisms of tongue color through the calculation and analysis of chromaticity parameters of CIE, combined with colorimetric system and CIE LAB color space, and these are consistent with the characteristics of clinical tongue color. Applying optical spectrum colorimetry technology to tongue color differentiation has the potential to serve as a reference point in standardizing traditional Chinese medicine syndrome classification in PHC.

  18. Chromatic energy filter and characterization of laser-accelerated proton beams for particle therapy

    Science.gov (United States)

    Hofmann, Ingo; Meyer-ter-Vehn, Jürgen; Yan, Xueqing; Al-Omari, Husam

    2012-07-01

    The application of laser accelerated protons or ions for particle therapy has to cope with relatively large energy and angular spreads as well as possibly significant random fluctuations. We suggest a method for combined focusing and energy selection, which is an effective alternative to the commonly considered dispersive energy selection by magnetic dipoles. Our method is based on the chromatic effect of a magnetic solenoid (or any other energy dependent focusing device) in combination with an aperture to select a certain energy width defined by the aperture radius. It is applied to an initial 6D phase space distribution of protons following the simulation output from a Radiation Pressure Acceleration model. Analytical formula for the selection aperture and chromatic emittance are confirmed by simulation results using the TRACEWIN code. The energy selection is supported by properly placed scattering targets to remove the imprint of the chromatic effect on the beam and to enable well-controlled and shot-to-shot reproducible energy and transverse density profiles.

  19. Chromatic energy filter and characterization of laser-accelerated proton beams for particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Ingo, E-mail: i.hofmann@gsi.de [Helmholtz-Institut Jena, Helmholtzweg 4, 07743 Jena (Germany); Gesellschaft fuer Schwerionenforschung (GSI), Planckstr. 1, 64291 Darmstadt (Germany); Meyer-ter-Vehn, Juergen [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Yan, Xueqing [State Key Laboratory of Nuclear Physics and Technology, CAPT, Peking University, Beijing 100871 (China); Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China); Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Al-Omari, Husam [Institute for Applied Physics, Goethe University Frankfurt, Max-von-Laue str. 1, 60438 Frankfurt (Germany); Gesellschaft fuer Schwerionenforschung (GSI), Planckstr. 1, 64291 Darmstadt (Germany)

    2012-07-21

    The application of laser accelerated protons or ions for particle therapy has to cope with relatively large energy and angular spreads as well as possibly significant random fluctuations. We suggest a method for combined focusing and energy selection, which is an effective alternative to the commonly considered dispersive energy selection by magnetic dipoles. Our method is based on the chromatic effect of a magnetic solenoid (or any other energy dependent focusing device) in combination with an aperture to select a certain energy width defined by the aperture radius. It is applied to an initial 6D phase space distribution of protons following the simulation output from a Radiation Pressure Acceleration model. Analytical formula for the selection aperture and chromatic emittance are confirmed by simulation results using the TRACEWIN code. The energy selection is supported by properly placed scattering targets to remove the imprint of the chromatic effect on the beam and to enable well-controlled and shot-to-shot reproducible energy and transverse density profiles.

  20. Symptomatic acquired zinc deficiency in at-risk premature infants: high dose preventive supplementation is necessary.

    Science.gov (United States)

    Barbarot, Sébastien; Chantier, Emilie; Kuster, Alice; Hello, Muriel; Roze, Jean-Christophe; Blouin, Eric; Stalder, Jean-François

    2010-01-01

    Zinc is a cofactor for several enzymes involved in many metabolisms. Zinc deficiency induces various disorders such as acrodermatitis enteropathica, either inherited or acquired. We report three cases of premature infants (24-31 wks gestational age) with low birthweight (650 to 940 g) and enteropathy, two of whom presented with necrotizing enterocolitis. All infants were fed by total parenteral nutrition. At a chronological age ranging from 73 to 80 days, all infants developed a periorificial dermatitis. Before the onset of the first signs, they had received zinc supplementation ranging from 146% to 195% of the recommended dose (400 microg/kg/day). Increased zinc supplementation over a course of 6-18 days induced a complete resolution of symptoms in all cases. No abnormality in the neurologic examination and no recurrence were observed at the end of the zinc treatment. Low birthweight premature infants with enteropathy on total parenteral nutrition are at risk of developing zinc deficiency. The usual recommended zinc supplementation is probably insufficient for those infants. A delay in the diagnosis of zinc deficiency may lead to severe complications.

  1. Effects of Chronic and Acute Zinc Supplementation on Myocardial Ischemia-Reperfusion Injury in Rats.

    Science.gov (United States)

    Ozyıldırım, Serhan; Baltaci, Abdulkerim Kasim; Sahna, Engin; Mogulkoc, Rasim

    2017-07-01

    The present study aims to explore the effects of chronic and acute zinc sulfate supplementation on myocardial ischemia-reperfusion injury in rats. The study registered 50 adult male rats which were divided into five groups in equal numbers as follows: group 1, normal control; group 2, sham; group 3, myocardial ischemia reperfusion (My/IR): the group which was fed on a normal diet and in which myocardial I/R was induced; group 4, myocardial ischemia reperfusion + chronic zinc: (5 mg/kg i.p. zinc sulfate for 15 days); and group 5, myocardial ischemia reperfusion + acute zinc: the group which was administered 15 mg/kg i.p. zinc sulfate an hour before the operation and in which myocardial I/R was induced. The collected blood and cardiac tissue samples were analyzed using spectrophotometric method to determine levels of MDA, as an indicator of tissue injury, and GSH, as an indicator of antioxidant activity. The highest plasma and heart tissue MDA levels were measured in group 3 (p zinc administration and markedly by chronic zinc supplementation.

  2. Spatial and temporal aspects of chromatic adaptation and their functional significance for colour constancy.

    Science.gov (United States)

    Werner, Annette

    2014-11-01

    Illumination in natural scenes changes at multiple temporal and spatial scales: slow changes in global illumination occur in the course of a day, and we encounter fast and localised illumination changes when visually exploring the non-uniform light field of three-dimensional scenes; in addition, very long-term chromatic variations may come from the environment, like for example seasonal changes. In this context, I consider the temporal and spatial properties of chromatic adaptation and discuss their functional significance for colour constancy in three-dimensional scenes. A process of fast spatial tuning in chromatic adaptation is proposed as a possible sensory mechanism for linking colour constancy to the spatial structure of a scene. The observed middlewavelength selectivity of this process is particularly suitable for adaptation to the mean chromaticity and the compensation of interreflections in natural scenes. Two types of sensory colour constancy are distinguished, based on the functional differences of their temporal and spatial scales: a slow type, operating at a global scale for the compensation of the ambient illumination; and a fast colour constancy, which is locally restricted and well suited to compensate region-specific variations in the light field of three dimensional scenes. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Zinc salt enhances gastroprotective activity of risperidone in indomethacin-induced gastric ulcer.

    Science.gov (United States)

    Oluwole, F S; Onwuchekwa, C

    2016-09-01

    Zinc has been reported to mediate cellular responses to injury by producing cytoprotection via the scavenging of reactive oxygen species. Anti-stress medications are generally anti-psychotic drugs and anti- depressants. Some Anti-psychotic drugs such as risperidone have been reported to possess anti-ulcer activity. Risperidone as an antipsychotic drug blocks several neurotransmitter systems including dopaminergic, adrenergic, histaminergic and serotonergic pathways. The study investigated the antiulcer activity of Zinc Chloride (ZnCl(2)) in combination with risperidone in male Wistar rats. The animals were divided into two groups of twenty animals each for ZnCl(2) and risperidone groups. Each group was further divided into four subgroups. ZnCl(2) was administered orally at 20mg/kg, 40mg/kg and 80mg/kg to a subgroup, while 80mg/kg of ZnCl(2) was administered in combination with risperidone (0.1mg/kg, 0.3mg/kg and 0.5mg/kg) orally once daily for 21 days. The controls were treated with distilled water. Ulcer was induced using indomethacin. Histology of the stomach tissues was prepared with PAS and H& E stains. Ulcer score and ulcer area were assessed using standard methods. Data were analysed using student t-test and Graphpad Prism 5. There were decreases in ulcer scores using the different doses of ZnCl, (20mg/kg, 40mg/kg and 80mg/kg). Also using the highest dose ZnCl(2) (80mg/ kg) and different doses of risperidone there were decreases in ulcer scores compared to the control. This effect of the risperidone showed a significant dose- dependent reduction. The effect ZnCl(2), and risperidone were also reflected in the ulcer area and in the histology. These findings suggest that ZnCl(2), enhances the gastroprotective activity ofrisperidone in indomethacin- induced gastric ulcer. However, more detailed studies are necessary to confirm the relevance of this finding and its implications in clinical settings.

  4. Meta-Transcriptomic Analysis of a Chromate-Reducing Aquifer Microbial Community

    Science.gov (United States)

    Beller, H. R.; Brodie, E. L.; Han, R.; Karaoz, U.

    2010-12-01

    A major challenge for microbial ecology that has become more tractable in the advent of new molecular techniques is characterizing gene expression in complex microbial communities. We are using meta-transcriptomic analysis to characterize functional changes in an aquifer-derived, chromate-reducing microbial community as it transitions through various electron-accepting conditions. We inoculated anaerobic microcosms with groundwater from the Cr-contaminated Hanford 100H site and supplemented them with lactate and electron acceptors present at the site, namely, nitrate, sulfate, and Fe(III). The microcosms progressed successively through various electron-accepting conditions (e.g., denitrifying, sulfate-reducing, and ferric iron-reducing conditions, as well as nitrate-dependent, chemolithotrophic Fe(II)-oxidizing conditions). Cr(VI) was rapidly reduced initially and again upon further Cr(VI) amendments. Extensive geochemical sampling and analysis (e.g., lactate, acetate, chloride, nitrate, nitrite, sulfate, dissolved Cr(VI), total Fe(II)), RNA/DNA harvesting, and PhyloChip analyses were conducted. Methods were developed for removal of rRNA from total RNA in preparation for meta-transcriptome sequencing. To date, samples representing denitrifying and fermentative/sulfate-reducing conditions have been sequenced using 454 Titanium technology. Of the non-rRNA related reads for the denitrifying sample (which was also actively reducing chromate), ca. 8% were associated with denitrification and ca. 0.9% were associated with chromate resistance/transport, in contrast to the fermentative/sulfate-reducing sample (in which chromate had already been reduced), which had zero reads associated with either of these categories but many predicted proteins associated with sulfate-reducing bacteria. We observed sequences for key functional transcripts that were unique at the nucleotide level compared to the GenBank non-redundant database [such as L-lactate dehydrogenase (iron

  5. [A Method for Selecting Self-Adoptive Chromaticity of the Projected Markers].

    Science.gov (United States)

    Zhao, Shou-bo; Zhang, Fu-min; Qu, Xing-hua; Zheng, Shi-wei; Chen, Zhe

    2015-04-01

    The authors designed a self-adaptive projection system which is composed of color camera, projector and PC. In detail, digital micro-mirror device (DMD) as a spatial light modulator for the projector was introduced in the optical path to modulate the illuminant spectrum based on red, green and blue light emitting diodes (LED). However, the color visibility of active markers is affected by the screen which has unknown reflective spectrum as well. Here active markers are projected spot array. And chromaticity feature of markers is sometimes submerged in similar spectral screen. In order to enhance the color visibility of active markers relative to screen, a method for selecting self-adaptive chromaticity of the projected markers in 3D scanning metrology is described. Color camera with 3 channels limits the accuracy of device characterization. For achieving interconversion of device-independent color space and device-dependent color space, high-dimensional linear model of reflective spectrum was built. Prior training samples provide additional constraints to yield high-dimensional linear model with more than three degrees of freedom. Meanwhile, spectral power distribution of ambient light was estimated. Subsequently, markers' chromaticity in CIE color spaces was selected via maximization principle of Euclidean distance. The setting values of RGB were easily estimated via inverse transform. Finally, we implemented a typical experiment to show the performance of the proposed approach. An 24 Munsell Color Checker was used as projective screen. Color difference in the chromaticity coordinates between the active marker and the color patch was utilized to evaluate the color visibility of active markers relative to the screen. The result comparison between self-adaptive projection system and traditional diode-laser light projector was listed and discussed to highlight advantage of our proposed method.

  6. Detailed spatiotemporal brain mapping of chromatic vision combining high-resolution VEP with fMRI and retinotopy.

    Science.gov (United States)

    Pitzalis, Sabrina; Strappini, Francesca; Bultrini, Alessandro; Di Russo, Francesco

    2018-03-13

    Neuroimaging studies have identified so far, several color-sensitive visual areas in the human brain, and the temporal dynamics of these activities have been separately investigated using the visual-evoked potentials (VEPs). In the present study, we combined electrophysiological and neuroimaging methods to determine a detailed spatiotemporal profile of chromatic VEP and to localize its neural generators. The accuracy of the present co-registration study was obtained by combining standard fMRI data with retinotopic and motion mapping data at the individual level. We found a sequence of occipito activities more complex than that typically reported for chromatic VEPs, including feed-forward and reentrant feedback. Results showed that chromatic human perception arises by the combined activity of at the least five parieto-occipital areas including V1, LOC, V8/VO, and the motion-sensitive dorsal region MT+. However, the contribution of V1 and V8/VO seems dominant because the re-entrant activity in these areas was present more than once (twice in V8/VO and thrice in V1). This feedforward and feedback chromatic processing appears delayed compared with the luminance processing. Associating VEPs and neuroimaging measures, we showed for the first time a complex spatiotemporal pattern of activity, confirming that chromatic stimuli produce intricate interactions of many different brain dorsal and ventral areas. © 2018 Wiley Periodicals, Inc.

  7. Zinc deprivation of methanol fed anaerobic granular sludge bioreactors

    Science.gov (United States)

    Fermoso, Fernando G.; Collins, Gavin; Bartacek, Jan

    2008-01-01

    The effect of omitting zinc from the influent of mesophilic (30 °C) methanol fed upflow anaerobic sludge bed (UASB) reactors, and latter zinc supplementation to the influent to counteract the deprivation, was investigated by coupling the UASB reactor performance to the microbial ecology of the bioreactor sludge. Limitation of the specific methanogenic activity (SMA) on methanol due to the absence of zinc from the influent developed after 137 days of operation. At that day, the SMA in medium with a complete trace metal solution except Zn was 3.4 g CH4-COD g VSS−1 day−1, compared to 4.2 g CH4-COD g VSS−1 day−1 in a medium with a complete (including zinc) trace metal solution. The methanol removal capacity during these 137 days was 99% and no volatile fatty acids accumulated. Two UASB reactors, inoculated with the zinc-deprived sludge, were operated to study restoration of the zinc limitation by zinc supplementation to the bioreactor influent. In a first reactor, no changes to the operational conditions were made. This resulted in methanol accumulation in the reactor effluent after 12 days of operation, which subsequently induced acetogenic activity 5 days after the methanol accumulation started. Methanogenesis could not be recovered by the continuous addition of 0.5 μM ZnCl2 to the reactor for 13 days. In the second reactor, 0.5 μM ZnCl2 was added from its start-up. Although the reactor stayed 10 days longer methanogenically than the reactor operated without zinc, methanol accumulation was observed in this reactor (up to 1.1 g COD-MeOH L−1) as well. This study shows that zinc limitation can induce failure of methanol fed UASB reactors due to acidification, which cannot be restored by resuming the continuous supply of the deprived metal. PMID:18283507

  8. Coded-subcarrier-aided chromatic dispersion monitoring scheme for flexible optical OFDM networks.

    Science.gov (United States)

    Tse, Kam-Hon; Chan, Chun-Kit

    2014-08-11

    A simple coded-subcarrier aided scheme is proposed to perform chromatic dispersion monitoring in flexible optical OFDM networks. A pair of coded label subcarriers is added to both edges of the optical OFDM signal spectrum at the edge transmitter node. Upon reception at any intermediate or the receiver node, chromatic dispersion estimation is performed, via simple direct detection, followed by electronic correlation procedures with the designated code sequences. The feasibility and the performance of the proposed scheme have been experimentally characterized. It provides a cost-effective monitoring solution for the optical OFDM signals across intermediate nodes in flexible OFDM networks.

  9. Rising Intracellular Zinc by Membrane Depolarization and Glucose in Insulin-Secreting Clonal HIT-T15 Beta Cells

    Directory of Open Access Journals (Sweden)

    Kira G. Slepchenko

    2012-01-01

    Full Text Available Zinc (Zn2+ appears to be intimately involved in insulin metabolism since insulin secretion is correlated with zinc secretion in response to glucose stimulation, but little is known about the regulation of zinc homeostasis in pancreatic beta-cells. This study set out to identify the intracellular zinc transient by imaging free cytosolic zinc in HIT-T15 beta-cells with fluorescent zinc indicators. We observed that membrane depolarization by KCl (30–60 mM was able to induce a rapid increase in cytosolic concentration of zinc. Multiple zinc transients of similar magnitude were elicited during repeated stimulations. The amplitude of zinc responses was not affected by the removal of extracellular calcium or zinc. However, the half-time of the rising slope was significantly slower after removing extracellular zinc with zinc chelator CaEDTA, suggesting that extracellular zinc affect the initial rising phase of zinc response. Glucose (10 mM induced substantial and progressive increases in intracellular zinc concentration in a similar way as KCl, with variation in the onset and the duration of zinc mobilization. It is known that the depolarization of beta-cell membrane is coupled with the secretion of insulin. Rising intracellular zinc concentration may act as a critical signaling factor in insulin metabolism of pancreatic beta-cells.

  10. Assessment of Systematic Chromatic Errors that Impact Sub-1% Photometric Precision in Large-Area Sky Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Li, T. S. [et al.

    2016-05-27

    Meeting the science goals for many current and future ground-based optical large-area sky surveys requires that the calibrated broadband photometry is stable in time and uniform over the sky to 1% precision or better. Past surveys have achieved photometric precision of 1-2% by calibrating the survey's stellar photometry with repeated measurements of a large number of stars observed in multiple epochs. The calibration techniques employed by these surveys only consider the relative frame-by-frame photometric zeropoint offset and the focal plane position-dependent illumination corrections, which are independent of the source color. However, variations in the wavelength dependence of the atmospheric transmission and the instrumental throughput induce source color-dependent systematic errors. These systematic errors must also be considered to achieve the most precise photometric measurements. In this paper, we examine such systematic chromatic errors using photometry from the Dark Energy Survey (DES) as an example. We define a natural magnitude system for DES and calculate the systematic errors on stellar magnitudes, when the atmospheric transmission and instrumental throughput deviate from the natural system. We conclude that the systematic chromatic errors caused by the change of airmass in each exposure, the change of the precipitable water vapor and aerosol in the atmosphere over time, and the non-uniformity of instrumental throughput over the focal plane, can be up to 2% in some bandpasses. We compare the calculated systematic chromatic errors with the observed DES data. For the test sample data, we correct these errors using measurements of the atmospheric transmission and instrumental throughput. The residual after correction is less than 0.3%. We also find that the errors for non-stellar objects are redshift-dependent and can be larger than those for stars at certain redshifts.

  11. Zinc supplementation induces CD4+CD25+Foxp3+ antigen-specific regulatory T cells and suppresses IFN-γ production by upregulation of Foxp3 and KLF-10 and downregulation of IRF-1.

    Science.gov (United States)

    Maywald, Martina; Rink, Lothar

    2017-08-01

    The essential trace element zinc plays a fundamental role in immune function and regulation since its deficiency is associated with autoimmunity, allergies, and transplant rejection. Thus, we investigated the influence of zinc supplementation on the Th1-driven alloreaction in mixed lymphocyte cultures (MLC), on generation of antigen-specific T cells, and analyzed underlying molecular mechanisms. Cell proliferation and pro-inflammatory cytokine production were monitored by [ 3 H]-thymidine proliferation assay and ELISA, respectively. Analysis of surface and intracellular T cell marker was performed by flow cytometry. Western blotting and mRNA analysis were used for Foxp3, KLF-10, and IRF-1 expression. Zinc supplementation on antigen-specific T cells in physiological doses (50 µM) provokes a significant amelioration of cell proliferation and pro-inflammatory cytokine production after reactivation compared to untreated controls. Zinc administration on MLC results in an increased induction and stabilization of CD4 + CD25 + Foxp3 + and CD4 + CD25 + CTLA-4 + T cells (p zinc-induced upregulation of Foxp3 and KLF-10 and downregulation of IRF-1. However, in resting lymphocytes zinc increases IRF-1. In summary, zinc is capable of ameliorating the allogeneic immune reaction by enhancement of antigen-specific iTreg cells due to modulation of essential molecular targets: Foxp3, KLF-10, and IRF-1. Thus, zinc can be seen as an auspicious tool for inducing tolerance in adverse immune reactions.

  12. Analysis of retinal function using chromatic pupillography in retinitis pigmentosa and the relationship to electrically evoked phosphene thresholds.

    Science.gov (United States)

    Kelbsch, Carina; Maeda, Fumiatsu; Lisowska, Jolanta; Lisowski, Lukasz; Strasser, Torsten; Stingl, Krunoslav; Wilhelm, Barbara; Wilhelm, Helmut; Peters, Tobias

    2017-06-01

    To analyse pupil responses to specific chromatic stimuli in patients with advanced retinitis pigmentosa (RP) to ascertain whether chromatic pupillography can be used as an objective marker for residual retinal function. To examine correlations between parameters of the pupil response and the perception threshold of electrically evoked phosphenes. Chromatic pupillography was performed in 40 patients with advanced RP (visual acuity Chromatic pupillography demonstrated a significant decrease in outer retinal photoreceptor responses but a persisting and disinhibited intrinsic photosensitive retinal ganglion cell function in advanced RP. These phenomena may be useful as an objective marker for the efficacy of any interventional treatment for hereditary retinal diseases as well as for the selection of suitable patients for an electronic retinal implant. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  13. Refractive and diffractive neutron optics with reduced chromatic aberration

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Poulsen, Henning Friis; Bentley, P.M.

    2014-01-01

    by the use of optics for focusing and imaging. Refractive and diffractive optical elements, e.g. compound refractive lenses and Fresnel zone plates, are attractive due to their low cost, and simple alignment. These optical elements, however, suffer from chromatic aberration, which limit their effectiveness...

  14. Modulations of anisotropic optical transmission on alumina-doped zinc oxide surface by femtosecond laser induced ripples

    Science.gov (United States)

    Lu, Yanhui; Jiang, Lan; Sun, Jingya; Cao, Qiang; Wang, Qingsong; Han, Weina; Lu, Yongfeng

    2018-04-01

    This study demonstrated that femtosecond-laser-induced ripples on an alumina-doped zinc oxide (AZO) film with space intervals of approximately 340 and 660 nm exhibit modulations of anisotropic optical transmission. At low laser fluence, ripples can not affect the original absorption peak of AZO film, but at higher laser fluence, the absorption peak of AZO film is disappeared due to the modulation by femtosecond laser induced ripples. Moreover, the relationship between the anisotropic optical transmission and the features of nanostructures is discussed. Ripples with a space interval of approximately 660 nm have a higher ability to block light than nanostructures with a space interval of approximately 340 nm. These observations indicate that anisotropic optical transmission has potential applications in the field of optoelectronics.

  15. Elimination of zinc-65 from the brain under kainate-induced seizures.

    Science.gov (United States)

    Takeda, Atsushi; Hirate, Maki; Oku, Naoto

    2004-04-01

    On the basis of the previous evidence that 65Zn concentrations in the brain of EL (epilepsy) mice was affected by induction of seizures, 65Zn movement in the brain was quantitatively evaluated in ddY mice treated with kainate. Six days after intravenous injection of 65ZnCl2, mice were intraperitoneally injected with kainate (10 mg/kg x 6 times in 2 weeks). Myoclonic jerks were observed during treatment with kainate. Twenty days after 65Zn injection, 65Zn distribution in the brain was compared between the kainite-treated and control mice. 65Zn distribution in the brain of the kainate-treated mice was overall lower than in the control mice. 65Zn concentration was significantly decreased in the frontal cortex, hippocampal CA1, thalamus and hypothalamus by treatment with kainate. These results demonstrate that kainate-induced seizures are linked to decreased zinc concentrations in the brain.

  16. Informational primacy of visual dimensions: specialized roles for luminance and chromaticity in figure-ground perception.

    Science.gov (United States)

    Yamagishi, N; Melara, R D

    2001-07-01

    Three experiments were conducted to examine the distinct contributions of two visual dimensions to figure-ground segregation. In each experiment, pattern identification was assessed by asking observers to judge whether a near-threshold test pattern was the same or different in shape to a high-contrast comparison pattern. A test pattern could differ from its background along one dimension, either luminance (luminance tasks) or chromaticity (chromaticity tasks). In each task, performance in a baseline condition, in which the test pattern was intact, was compared with performance in each of several degradation conditions, in which either the contour or the surface of the figure was degraded, using either partial occlusion (Experiment 1) or ramping (Experiments 2 and 3) of figure-ground differences. In each experiment, performance in luminance tasks was worst when the contour was degraded, whereas performance in chromaticity tasks was worst when the surface was degraded. This interaction was found even when spatial frequencies were fixed across test patterns by low-pass filtering. The results are consistent with a late (postfiltering) dual-mechanism system that processes luminance information to extract boundary representations and chromaticity information to extract surface representations.

  17. A Zinc Chelator TPEN Attenuates Airway Hyperresponsiveness Airway Inflammation in Mice In Vivo

    Directory of Open Access Journals (Sweden)

    Satoru Fukuyama

    2011-01-01

    Conclusions: In pulmonary allergic inflammation induced in mice immunized with antigen without alum, zinc chelator inhibits airway inflammation and hyperresponsiveness. These findings suggest that zinc may be a therapeutic target of allergic asthma.

  18. Schottky signal analysis: tune and chromaticity computation

    CERN Document Server

    Chanon, Ondine

    2016-01-01

    Schottky monitors are used to determine important beam parameters in a non-destructive way. The Schottky signal is due to the internal statistical fluctuations of the particles inside the beam. In this report, after explaining the different components of a Schottky signal, an algorithm to compute the betatron tune is presented, followed by some ideas to compute machine chromaticity. The tests have been performed with offline and/or online LHC data.

  19. Study of chromate coatings by radioisotope tracing

    International Nuclear Information System (INIS)

    Drozda, T.; Maleczki, E.; Farkas, G.

    1984-01-01

    New radioactive tracer methods were developed to determine chromium(III) and total chromium [chromium(III)+chromium(VI)] content simultaneously. They are capable of investigating solutions and the conversion coating itself in the solid phase, respectively. The increase of chromium(III) concentration in the yellow chromate coating, and the chromium(III) to total chromium ratio in the conversion coating were determined as a function of the treating period. (author)

  20. Protective effect of zinc against ischemic neuronal injury in a middle cerebral artery occlusion model.

    Science.gov (United States)

    Kitamura, Youji; Iida, Yasuhiko; Abe, Jun; Ueda, Masashi; Mifune, Masaki; Kasuya, Fumiyo; Ohta, Masayuki; Igarashi, Kazuo; Saito, Yutaka; Saji, Hideo

    2006-02-01

    In this study, we investigated the effect of vesicular zinc on ischemic neuronal injury. In cultured neurons, addition of a low concentration (under 100 microM) of zinc inhibited both glutamate-induced calcium influx and neuronal death. In contrast, a higher concentration (over 150 microM) of zinc decreased neuronal viability, although calcium influx was inhibited. These results indicate that zinc exhibits biphasic effects depending on its concentration. Furthermore, in cultured neurons, co-addition of glutamate and CaEDTA, which binds extra-cellular zinc, increased glutamate-induced calcium influx and aggravated the neurotoxicity of glutamate. In a rat transient middle cerebral artery occlusion (MCAO) model, the infarction volume, which is related to the neurotoxicity of glutamate, increased rapidly on the intracerebral ventricular injection of CaEDTA 30 min prior to occlusion. These results suggest that zinc released from synaptic vesicles may provide a protective effect against ischemic neuronal injury.

  1. Estimation of chromatic errors from broadband images for high contrast imaging

    Science.gov (United States)

    Sirbu, Dan; Belikov, Ruslan

    2015-09-01

    Usage of an internal coronagraph with an adaptive optical system for wavefront correction for direct imaging of exoplanets is currently being considered for many mission concepts, including as an instrument addition to the WFIRST-AFTA mission to follow the James Web Space Telescope. The main technical challenge associated with direct imaging of exoplanets with an internal coronagraph is to effectively control both the diffraction and scattered light from the star so that the dim planetary companion can be seen. For the deformable mirror (DM) to recover a dark hole region with sufficiently high contrast in the image plane, wavefront errors are usually estimated using probes on the DM. To date, most broadband lab demonstrations use narrowband filters to estimate the chromaticity of the wavefront error, but this reduces the photon flux per filter and requires a filter system. Here, we propose a method to estimate the chromaticity of wavefront errors using only a broadband image. This is achieved by using special DM probes that have sufficient chromatic diversity. As a case example, we simulate the retrieval of the spectrum of the central wavelength from broadband images for a simple shaped- pupil coronagraph with a conjugate DM and compute the resulting estimation error.

  2. Integration of polarization and chromatic cues in the insect sky compass.

    Science.gov (United States)

    el Jundi, Basil; Pfeiffer, Keram; Heinze, Stanley; Homberg, Uwe

    2014-06-01

    Animals relying on a celestial compass for spatial orientation may use the position of the sun, the chromatic or intensity gradient of the sky, the polarization pattern of the sky, or a combination of these cues as compass signals. Behavioral experiments in bees and ants, indeed, showed that direct sunlight and sky polarization play a role in sky compass orientation, but the relative importance of these cues are species-specific. Intracellular recordings from polarization-sensitive interneurons in the desert locust and monarch butterfly suggest that inputs from different eye regions, including polarized-light input through the dorsal rim area of the eye and chromatic/intensity gradient input from the main eye, are combined at the level of the medulla to create a robust compass signal. Conflicting input from the polarization and chromatic/intensity channel, resulting from eccentric receptive fields, is eliminated at the level of the anterior optic tubercle and central complex through internal compensation for changing solar elevations, which requires input from a circadian clock. Across several species, the central complex likely serves as an internal sky compass, combining E-vector information with other celestial cues. Descending neurons, likewise, respond both to zenithal polarization and to unpolarized cues in an azimuth-dependent way.

  3. The zinc dyshomeostasis hypothesis of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Travis J A Craddock

    Full Text Available Alzheimer's disease (AD is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ, intracellular neurofibrillary tangles (NFTs composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau, and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1 used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2 performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3 used metallomic imaging mass spectrometry (MIMS to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of

  4. The zinc dyshomeostasis hypothesis of Alzheimer's disease.

    Science.gov (United States)

    Craddock, Travis J A; Tuszynski, Jack A; Chopra, Deepak; Casey, Noel; Goldstein, Lee E; Hameroff, Stuart R; Tanzi, Rudolph E

    2012-01-01

    Alzheimer's disease (AD) is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ), intracellular neurofibrillary tangles (NFTs) composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau), and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques) not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1) used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2) performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3) used metallomic imaging mass spectrometry (MIMS) to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of polymerized

  5. Analysis of preservative-treated wood by multivariate analysis of laser-induced breakdown spectroscopy spectra

    International Nuclear Information System (INIS)

    Martin, Madhavi Z.; Labbe, Nicole; Rials, Timothy G.; Wullschleger, Stan D.

    2005-01-01

    In this work, multivariate statistical analysis (MVA) techniques are coupled with laser-induced breakdown spectroscopy (LIBS) to identify preservative types (chromated copper arsenate, ammoniacal copper zinc or alkaline copper quat), and to predict elemental content in preservative-treated wood. The elemental composition of the samples was measured with a standard laboratory method of digestion followed by atomic absorption spectroscopy analysis. The elemental composition was then correlated with the LIBS spectra using projection to latent structures (PLS) models. The correlations for the different elements introduced by different treatments were very strong, with the correlation coefficients generally above 0.9. Additionally, principal component analysis (PCA) was used to differentiate the samples treated with different preservative formulations. The research has focused not only on demonstrating the application of LIBS as a tool for use in the forest products industry, but also considered sampling errors, limits of detection, reproducibility, and accuracy of measurements as they relate to multivariate analysis of this complex wood substrate

  6. Analysis of preservative-treated wood by multivariate analysis of laser-induced breakdown spectroscopy spectra

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z. [Environmental Sciences Division Oak Ridge National Laboratory, P.O. Box 2008 MS 6422, Oak Ridge TN 37831-6422 (United States); Labbe, Nicole [Forest Products Center, University of Tennessee, 2506 Jacob Drive, Knoxville, TN 37996-4570 (United States)]. E-mail: nlabbe@utk.edu; Rials, Timothy G. [Forest Products Center, University of Tennessee, 2506 Jacob Drive, Knoxville, TN 37996-4570 (United States); Wullschleger, Stan D. [Environmental Sciences Division Oak Ridge National Laboratory, P.O. Box 2008 MS 6422, Oak Ridge TN 37831-6422 (United States)

    2005-08-31

    In this work, multivariate statistical analysis (MVA) techniques are coupled with laser-induced breakdown spectroscopy (LIBS) to identify preservative types (chromated copper arsenate, ammoniacal copper zinc or alkaline copper quat), and to predict elemental content in preservative-treated wood. The elemental composition of the samples was measured with a standard laboratory method of digestion followed by atomic absorption spectroscopy analysis. The elemental composition was then correlated with the LIBS spectra using projection to latent structures (PLS) models. The correlations for the different elements introduced by different treatments were very strong, with the correlation coefficients generally above 0.9. Additionally, principal component analysis (PCA) was used to differentiate the samples treated with different preservative formulations. The research has focused not only on demonstrating the application of LIBS as a tool for use in the forest products industry, but also considered sampling errors, limits of detection, reproducibility, and accuracy of measurements as they relate to multivariate analysis of this complex wood substrate.

  7. Chromatic roots and minor-closed families of graphs

    DEFF Research Database (Denmark)

    Perrett, Thomas

    2016-01-01

    Given a minor-closed class of graphs G, what is the in mum of the non-trivial roots of the chromatic polynomial of G ε G? When G is the class of all graphs, the answer is known to be 32/27. We answer this question exactly for three minor-closed classes of graphs. Furthermore, we conjecture precis...

  8. In vivo subjective and objective longitudinal chromatic aberration after bilateral implantation of the same design of hydrophobic and hydrophilic intraocular lenses.

    Science.gov (United States)

    Vinas, Maria; Dorronsoro, Carlos; Garzón, Nuria; Poyales, Francisco; Marcos, Susana

    2015-10-01

    To measure the longitudinal chromatic aberration in vivo using psychophysical and wavefront-sensing methods in patients with bilateral implantation of monofocal intraocular lenses (IOLs) of similar aspheric design but different materials (hydrophobic Podeye and hydrophilic Poday). Instituto de Optica, Consejo Superior de Investigaciones Cientificas, Madrid, Spain. Prospective observational study. Measurements were performed with the use of psychophysical (480 to 700 nm) and wavefront-sensing (480 to 950 nm) methods using a custom-developed adaptive optics system. Chromatic difference-of-focus curves were obtained from best-focus data at each wavelength, and the longitudinal chromatic aberration was obtained from the slope of linear regressions to those curves. The longitudinal chromatic aberration from psychophysical measurements was 1.37 diopters (D) ± 0.08 (SD) (hydrophobic) and 1.21 ± 0.08 D (hydrophilic). From wavefront-sensing, the longitudinal chromatic aberration was 0.88 ± 0.07 D and 0.73 ± 0.09 D, respectively. At 480 to 950 nm, the longitudinal chromatic aberration was 1.27 ± 0.09 D (hydrophobic) and 1.02 ± 0.13 D (hydrophilic). The longitudinal chromatic aberration was consistently higher in eyes with the hydrophobic IOL than in eyes with the hydrophilic IOL (a difference of 0.16 D and 0.15 D, respectively). Similar to findings in young phakic eyes, the longitudinal chromatic aberration from the psychophysical method was consistently higher than from wavefront-sensing, by 0.48 D (35.41%) for the hydrophobic IOL and 0.48 D (39.43%) for the hydrophilic IOL. Longitudinal chromatic aberrations were smaller with hydrophilic IOLs than with hydrophobic IOLs of the same design. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. Characterisation of Vranec, Cabernet sauvignon and Merlot wines based on their chromatic and anthocyanin profiles

    OpenAIRE

    Dimitrovska Maja; Tomovska Elena; Bocevska Mirjana

    2013-01-01

    Wines of three different grape varieties, Vranec, Cabernet Sauvignon and Merlot were examined for their characterisation in terms of anthocyanin and chromatic profiles, total polyphenols and antioxidant potential. Total, monomeric, polymeric and copigmented anthocyanins were determined by spectrophotometry and the individual anthocyanin compounds were quantified using HPLC-DAD. Chromatic profile was evaluated according to colour density, hue, % red, % blue, % yellow and brilliance (% dA...

  10. Shock-induced fast reactions of zinc nanoparticles and RDX

    International Nuclear Information System (INIS)

    Xue Mian; Wu Jinghe; Ye Song; Yang Xiangdong; Hu Dong; Wang Yanping; Zhu Wenjun; Li Chengbing

    2008-01-01

    Fast reactions of zinc nanoparticles and RDX were investigated in normal incident shock waves. The emergence time and emission spectra intensity of partial products such as NO 2 , H, C 2 , O, CO, CH 2 O, CO 2 , H 2 O and ZnO were observed by a TDS5054 oscilloscope. The results indicate that NO 2 appears first in each experiment, which is in agreement with the theoretical results. The addition of zinc nanoparticles to RDX can not only shorten the ignition delay time by 20% but also double the shockwave diffusion velocity to 2180 ± 50 m s -1 and triple the temperature to 2020 ± 60 K. The emergence time of products shortens by around 10-40% and the emission spectra intensity of H 2 O and CH 2 O rises by about three times and one times, respectively. CO 2 , H 2 O and O 2 in various concentrations were introduced into the zinc-RDX reaction, respectively, which indicate that O 2 made the ignition delay time shorten by over 30%, the effect of H 2 O was not prominent while CO 2 made the ignition delay time lag by around 30%. The results indicate that the Zn-O 2 reaction mainly occurs in O 2 , CO 2 and H 2 O

  11. PSB Chromaticity Correction in both Planes

    CERN Document Server

    Bartosik, Hannes; CERN. Geneva. ATS Department

    2017-01-01

    In view of the LHC injector upgrade program (LIU[1]), all LHC pre-accelerators and in particular the CERN Booster (PSB) are being reviewed for potential lattice optics and equipment optimizations. The option to correct the chromaticity in both planes would be very helpful for a better control of the beam in the presence of both non-linearities and space charge. Moreover, one could reduce decoherence phenomena that otherwise limit the usefulness of resonance measurement techniques based on a turn-by-turn BPM system.

  12. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

    OpenAIRE

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-01

    Background In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. Methods A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3?mm of pupil diameter and...

  13. The influence of L-opsin gene polymorphisms and neural ageing on spatio-chromatic contrast sensitivity in 20-71 year olds.

    Science.gov (United States)

    Dees, Elise W; Gilson, Stuart J; Neitz, Maureen; Baraas, Rigmor C

    2015-11-01

    Chromatic contrast sensitivity may be a more sensitive measure of an individual's visual function than achromatic contrast sensitivity. Here, the first aim was to quantify individual- and age-related variations in chromatic contrast sensitivity to a range of spatial frequencies for stimuli along two complementary directions in color space. The second aim was to examine whether polymorphisms at specific amino acid residues of the L- and M-opsin genes (OPN1LW and OPN1MW) known to affect spectral tuning of the photoreceptors could influence spatio-chromatic contrast sensitivity. Chromatic contrast sensitivity functions were measured in 50 healthy individuals (20-71 years) employing a novel pseudo-isochromatic grating stimulus. The spatio-chromatic contrast sensitivity functions were found to be low pass for all subjects, independent of age and color vision. The results revealed a senescent decline in spatio-chromatic contrast sensitivity. There were considerable between-individual differences in sensitivity within each age decade for individuals 49 years old or younger, and age did not predict sensitivity for these age decades alone. Forty-six subjects (including a color deficient male and eight female carriers) were genotyped for L- and M-opsin genes. The Ser180Ala polymorphisms on the L-opsin gene were found to influence the subject's color discrimination and their sensitivity to spatio-chromatic patterns. The results expose the significant role of neural and genetic factors in the deterioration of visual function with increasing age. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. An environmentally acceptable primer for galvanized steel: Formulation and evaluation by SVET

    Energy Technology Data Exchange (ETDEWEB)

    Simoes, A.M.P., E-mail: alda.simoes@ist.utl.p [CIDEPINT - Centro de Investigacion y Desarrollo en Tecnologia de Pinturas (CIC-CONICET), Calle 52 e/121 y 122, 1900 La Plata (Argentina); TULisbon, Instituto Superior Tecnico, DEQB, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Carbonari, R.O.; Di Sarli, A.R.; Amo, B. del [CIDEPINT - Centro de Investigacion y Desarrollo en Tecnologia de Pinturas (CIC-CONICET), Calle 52 e/121 y 122, 1900 La Plata (Argentina); TULisbon, Instituto Superior Tecnico, DEQB, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Romagnoli, R., E-mail: estelectro@cidepint.gov.a [CIDEPINT - Centro de Investigacion y Desarrollo en Tecnologia de Pinturas (CIC-CONICET), Calle 52 e/121 y 122, 1900 La Plata (Argentina); TULisbon, Instituto Superior Tecnico, DEQB, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2011-01-15

    Research highlights: {yields} Chromates can be replaced successfully by aluminium phosphosilicate in paint systems. {yields} The solvents of the primer are eco-friendly ones. {yields} The primer adheres on galvanized steel and allows top-coating. {yields} The binder of the primer is compatible with other binders for top-coating. - Abstract: The object of this paper was to formulate a two-pack wash primer employing aluminium phosphosilicate as active anticorrosive pigment instead of basic zinc chromate. The anticorrosive action of the primer was evaluated by the polarization technique and the scanning vibrating electrode technique (SVET). The exposed surface was then examined by scanning electron microscopy (SEM) and the surface composition determined by energy dispersive X-ray (EDX) analysis. The primer was finally integrated in a complete paint scheme whose anticorrosive performance was evaluated by the salt spray chamber and electrochemical impedance spectroscopy. The adhesion of the primer plus a painting system was also evaluated by standard ASTM D 3359-90 test method. The wash primer pigmented with zinc chromate was used as reference. Results indicated that basic zinc chromate could be replaced by the more eco-friendly wash-primer containing aluminium phosphosilicate.

  15. Aflatoxin B1 Induced Systemic Toxicity in Poultry and Rescue Effects of Selenium and Zinc.

    Science.gov (United States)

    Mughal, Muhammad Jameel; Peng, Xi; Kamboh, Asghar Ali; Zhou, Yi; Fang, Jing

    2017-08-01

    Among many challenges, exposure to aflatoxins, particularly aflatoxin B 1 (AFB 1 ), is one of the major concerns in poultry industry. AFB 1 intoxication results in decreased meat/egg production, hepatotoxicity, nephrotoxicity, disturbance in gastrointestinal tract (GIT) and reproduction, immune suppression, and increased disease susceptibility. Selenium (Se) and zinc (Zn), in dietary supplementation, offer easy, cost-effective, and efficient ways to neutralize the toxic effect of AFB 1 . In the current review, we discussed the impact of AFB 1 on poultry industry, its biotransformation, and organ-specific noxious effects, along with the action mechanism of AFB 1 -induced toxicity. Moreover, we explained the biological and detoxifying roles of Se and Zn in avian species as well as the protection mechanism of these two trace elements. Ultimately, we discussed the use of Se and Zn supplementation against AFB 1 -induced toxicity in poultry birds.

  16. Zinc-induced cardiomyocyte relaxation in a rat model of hyperglycemia is independent of myosin isoform

    Directory of Open Access Journals (Sweden)

    Yi Ting

    2012-11-01

    Full Text Available Abstract It has been reported previously that diabetic cardiomyopathy can be inhibited or reverted with chronic zinc supplementation. In the current study, we hypothesized that total cardiac calcium and zinc content is altered in early onset diabetes mellitus characterized in part as hyperglycemia (HG and that exposure of zinc ion (Zn2+ to isolated cardiomyocytes would enhance contraction-relaxation function in HG more so than in nonHG controls. To better control for differential cardiac myosin isoform expression as occurs in rodents after β-islet cell necrosis, hypothyroidism was induced in 16 rats resulting in 100% β-myosin heavy chain expression in the heart. β-Islet cell necrosis was induced in half of the rats by streptozocin administration. After 6 wks of HG, both HG and nonHG controls rats demonstrated similar myofilament performance measured as thin filament calcium sensitivity, native thin filament velocity in the myosin motility assay and contractile velocity and power. Extracellular Zn2+ reduced cardiomyocyte contractile function in both groups, but enhanced relaxation function significantly in the HG group compared to controls. Most notably, a reduction in diastolic sarcomere length with increasing pacing frequencies, i.e., incomplete relaxation, was more pronounced in the HG compared to controls, but was normalized with extracellular Zn2+ application. This is a novel finding implicating that the detrimental effect of HG on cardiomyocyte Ca2+ regulation can be amelioration by Zn2+. Among the many post-translational modifications examined, only phosphorylation of ryanodine receptor (RyR at S-2808 was significantly higher in HG compared to nonHG. We did not find in our hypothyroid rats any differentiating effects of HG on myofibrillar protein phosphorylation, lysine acetylation, O-linked N-acetylglucosamine and advanced glycated end-products, which are often implicated as complicating factors in cardiac performance due to HG. Our

  17. [Improvement in zinc nutrition due to zinc transporter-targeting strategy].

    Science.gov (United States)

    Kambe, Taiho

    2016-07-01

    Adequate intake of zinc from the daily diet is indispensable to maintain health. However, the dietary zinc content often fails to fulfill the recommended daily intake, leading to zinc deficiency and also increases the risk of developing chronic diseases, particularly in elderly individuals. Therefore, increased attention is required to overcome zinc deficiency and it is important to improve zinc nutrition in daily life. In the small intestine, the zinc transporter, ZIP4, functions as a component that is essential for zinc absorption. In this manuscript, we present a brief overview regarding zinc deficiency. Moreover, we review a novel strategy, called "ZIP4-targeting", which has the potential to enable efficient zinc absorption from the diet. ZIP4-targeting strategy is possibly a major step in preventing zinc deficiency and improving human health.

  18. Metallothionein provides zinc-mediated protective effects against methamphetamine toxicity in SK-N-SH cells.

    Science.gov (United States)

    Ajjimaporn, Amornpan; Swinscoe, John; Shavali, Shaik; Govitrapong, Piyarat; Ebadi, Manuchair

    2005-11-30

    Methamphetamine (METH) is a drug of abuse and neurotoxin that induces Parkinson's-like pathology after chronic usage by targeting dopaminergic neurons. Elucidation of the intracellular mechanisms that underlie METH-induced dopaminergic neuron toxicity may help in understanding the mechanism by which neurons die in Parkinson's disease. In the present study, we examined the role of reactive oxygen species (ROS) in the METH-induced death of human dopaminergic SK-N-SH cells and further assessed the neuroprotective effects of zinc and metallothionein (MT) against METH-induced toxicity in culture. METH significantly increased the production of reactive oxygen species, decreased intracellular ATP levels and reduced the cell viability. Pre-treatment with zinc markedly prevented the loss of cell viability caused by METH treatment. Zinc pre-treatment mainly increased the expression of metallothionein and prevented the generation of reactive oxygen species and ATP depletion caused by METH. Chelation of zinc by CaEDTA caused a significant decrease in MT expression and loss of protective effects of MT against METH toxicity. These results suggest that zinc-induced MT expression protects dopaminergic neurons via preventing the accumulation of toxic reactive oxygen species and halting the decrease in ATP levels. Furthermore, MT may prevent the loss of mitochondrial functions caused by neurotoxins. In conclusion, our study suggests that MT, a potent scavenger of free radicals is neuroprotective against dopaminergic toxicity in conditions such as drug of abuse and in Parkinson's disease.

  19. Zinc content of selected tissues and taste perception in rats fed zinc deficient and zinc adequate rations

    International Nuclear Information System (INIS)

    Boeckner, L.S.; Kies, C.

    1986-01-01

    The objective of the study was to determine the effects of feeding zinc sufficient and zinc deficient rations on taste sensitivity and zinc contents of selected organs in rats. The 36 Sprague-Dawley male weanling rats were divided into 2 groups and fed zinc deficient or zinc adequate rations. The animals were subjected to 4 trial periods in which a choice of deionized distilled water or a solution of quinine sulfate at 1.28 x 10 -6 was given. A randomized schedule for rat sacrifice was used. No differences were found between zinc deficient and zinc adequate rats in taste preference aversion scores for quinine sulfate in the first three trial periods; however, in the last trial period rats in the zinc sufficient group drank somewhat less water containing quinine sulfate as a percentage of total water consumption than did rats fed the zinc deficient ration. Significantly higher zinc contents of kidney, brain and parotid salivary glands were seen in zinc adequate rats compared to zinc deficient rats at the end of the study. However, liver and tongue zinc levels were lower for both groups at the close of the study than were those of rats sacrificed at the beginning of the study

  20. Study of chromatic adaptation using memory color matches, Part I: neutral illuminants.

    Science.gov (United States)

    Smet, Kevin A G; Zhai, Qiyan; Luo, Ming R; Hanselaer, Peter

    2017-04-03

    Twelve corresponding color data sets have been obtained using the long-term memory colors of familiar objects as target stimuli. Data were collected for familiar objects with neutral, red, yellow, green and blue hues under 4 approximately neutral illumination conditions on or near the blackbody locus. The advantages of the memory color matching method are discussed in light of other more traditional asymmetric matching techniques. Results were compared to eight corresponding color data sets available in literature. The corresponding color data was used to test several linear (von Kries, RLAB, etc.) and nonlinear (Hunt & Nayatani) chromatic adaptation transforms (CAT). It was found that a simple two-step von Kries, whereby the degree of adaptation D is optimized to minimize the DEu'v' prediction errors, outperformed all other tested models for both memory color and literature corresponding color sets, whereby prediction errors were lower for the memory color sets. The predictive errors were substantially smaller than the standard uncertainty on the average observer and were comparable to what are considered just-noticeable-differences in the CIE u'v' chromaticity diagram, supporting the use of memory color based internal references to study chromatic adaptation mechanisms.

  1. Proton microprobe analysis of zinc in skeletal tissues. [Proton induced x-ray emission analysis

    Energy Technology Data Exchange (ETDEWEB)

    Doty, S B; Jones, K W; Kraner, H W; Shroy, R E; Hanson, A L

    1980-06-01

    A proton microprobe with windowless exit port was used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage.

  2. Comparative Study of Antidiabetic Activity and Oxidative Stress Induced by Zinc Oxide Nanoparticles and Zinc Sulfate in Diabetic Rats.

    Science.gov (United States)

    Nazarizadeh, Ali; Asri-Rezaie, Siamak

    2016-08-01

    In the current study, antidiabetic activity and toxic effects of zinc oxide nanoparticles (ZnO) were investigated in diabetic rats compared to zinc sulfate (ZnSO4) with particular emphasis on oxidative stress parameters. One hundred and twenty male Wistar rats were divided into two healthy and diabetic groups, randomly. Each major group was further subdivided into five subgroups and then orally supplemented with various doses of ZnO (1, 3, and 10 mg/kg) and ZnSO4 (30 mg/kg) for 56 consecutive days. ZnO showed greater antidiabetic activity compared to ZnSO4 evidenced by improved glucose disposal, insulin levels, and zinc status. The altered activities of erythrocyte antioxidant enzymes as well as raised levels of lipid peroxidation and a marked reduction of total antioxidant capacity were observed in rats receiving ZnO. ZnO nanoparticles acted as a potent antidiabetic agent, however, severely elicited oxidative stress particularly at higher doses.

  3. Skew chromaticity in large accelerators

    International Nuclear Information System (INIS)

    Peggs, S.; Dell, G.F.

    1995-01-01

    The 2-D ''skew chromaticity'' vector k is introduced when the standard on-momentum description of linear coupling is extended to include off-momentum particles. A lattice that is well decoupled on-momentum may be badly decoupled off-momentum, inside the natural momentum spread of the beam. There are two general areas of concern: (1) the free space in the tune plane is decreased; (2) collective phenomena may be destabilized. Two strong new criteria for head-tail stability in the presence of off-momentum coupling are derived, which are consistent with experimental and operational observations at the Tevatron, and with tracking data from RHIC

  4. On the chromatic number of triangle-free graphs of large minimum degree

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2002-01-01

    We prove that, for each. fixed real number c > 1/3, the triangle-free graphs of minimum degree at least cn (where n is the number of vertices) have bounded chromatic number. This problem was raised by Erdos and Simonovits in 1973 who pointed out that there is no such result for c <1/3.......We prove that, for each. fixed real number c > 1/3, the triangle-free graphs of minimum degree at least cn (where n is the number of vertices) have bounded chromatic number. This problem was raised by Erdos and Simonovits in 1973 who pointed out that there is no such result for c

  5. Theoretical estimates of spherical and chromatic aberration in photoemission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, J.P.S., E-mail: fit@pdx.edu; Word, R.C.; Könenkamp, R.

    2016-01-15

    We present theoretical estimates of the mean coefficients of spherical and chromatic aberration for low energy photoemission electron microscopy (PEEM). Using simple analytic models, we find that the aberration coefficients depend primarily on the difference between the photon energy and the photoemission threshold, as expected. However, the shape of the photoelectron spectral distribution impacts the coefficients by up to 30%. These estimates should allow more precise correction of aberration in PEEM in experimental situations where the aberration coefficients and precise electron energy distribution cannot be readily measured. - Highlights: • Spherical and chromatic aberration coefficients of the accelerating field in PEEM. • Compact, analytic expressions for coefficients depending on two emission parameters. • Effect of an aperture stop on the distribution is also considered.

  6. TREATMENT TESTS FOR EX SITU REMOVAL OF CHROMATE & NITRATE & URANIUM (VI) FROM HANFORD (100-HR-3) GROUNDWATER FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    BECK MA; DUNCAN JB

    1994-01-03

    This report describes batch and ion exchange column laboratory scale studies investigating ex situ methods to remove chromate (chromium [VI]), nitrate (NO{sub 3}{sup -}) and uranium (present as uranium [VI]) from contaminated Hanford site groundwaters. The technologies investigated include: chemical precipitation or coprecipitation to remove chromate and uranium; and anion exchange to remove chromate, uranium and nitrate. The technologies investigated were specified in the 100-HR-3 Groundwater Treatability Test Plan. The method suggested for future study is anion exchange.

  7. Zinc absorption in experimental osmotic diarrhea: effect of long-chain fatty acids.

    Science.gov (United States)

    Lee, S Y; Wapnir, R A

    1993-03-01

    The effect of free fatty acids on zinc absorption was studied in a rat model of chronic osmotic diarrhea induced with magnesium citrate and phenolphthalein. In vivo rates of zinc removal from the lumen and analysis of tissue for zinc uptake and metallothionein alterations were monitored. One mmol/L stearate enhanced zinc absorption in rats with or without diarrhea, from 207 +/- 22 and 353 +/- 13 pmol/min x cm to 676 +/- 34 and 610 +/- 26 pmol/min x cm, respectively. Palmitate was only effective in normal rats. Zinc absorption inversely correlated with mucosal zinc content in the perfused intestinal segments, in both type of rats. Hepatic metallothionein was enhanced by zinc and even more by oleate plus zinc in both groups; kidney metallothionein in animals with diarrhea was normalized by either oleate or zinc. The data support previous reports on the effect of long-chain fatty acids on the enhancement of zinc absorption: saturation and a longer chain appear to be positive factors. A membrane modification role of long-chain fatty acids could have nutritional implications in the formulation of special diets.

  8. Chromatic annuli formation and sample oxidation on copper thin films by femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    He, Shutong [Ultrafast Laser Laboratory, Key Laboratory of Opto-Electronic Information Technical Science of Ministry of Education, College of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072 (China); Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Amoruso, Salvatore [Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Pang, Dongqing; Wang, Chingyue; Hu, Minglie, E-mail: huminglie@tju.edu.cn [Ultrafast Laser Laboratory, Key Laboratory of Opto-Electronic Information Technical Science of Ministry of Education, College of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072 (China)

    2016-04-28

    We report an experimental investigation on the irradiation of copper thin films with high repetition rate femtosecond laser pulses (1040 nm, 50 MHz), in ambient air and liquid water. We observe a novel, striking phenomenon of chromatic copper oxides (CuO and Cu{sub 2}O) annuli generation. The characteristic features of the chromatic copper oxide annuli are studied by exploiting micro-Raman spectroscopy, optical and scanning electron microscopies. In the case of irradiation in water, the seldom investigated effects of the immersion time, t{sub w}, after irradiation with a fixed number of pulses are analyzed, and an intriguing dependence of the color of the chromatic annuli on t{sub w} is observed. This remarkable behavior is explained by proposing an interpretation scenario addressing the various processes involved in the process. Our experimental findings show that Cu{sub 2}O nanoparticles (size of ≈20 nm) and Cu{sub 2}O nanocubes (nanocube edges of ≈30, ≈60 nm) can be effectively generated by exploiting high repetition rate laser-assisted oxidation.

  9. Lead chromate detected as a source of atmospheric Pb and Cr (VI) pollution

    Science.gov (United States)

    Lee, Pyeong-Koo; Yu, Soonyoung; Chang, Hye Jung; Cho, Hye Young; Kang, Min-Ju; Chae, Byung-Gon

    2016-10-01

    Spherical black carbon aggregates were frequently observed in dust dry deposition in Daejeon, Korea. They were tens of micrometers in diameter and presented a mixture of black carbon and several mineral phases. Transmission electron microscopy (TEM) observations with energy-dispersive X-ray spectroscopy (EDS) and selected area diffraction pattern (SADP) analyses confirmed that the aggregates were compact and included significant amounts of lead chromate (PbCrO4). The compositions and morphologies of the nanosized lead chromate particles suggest that they probably originated from traffic paint used in roads and were combined as discrete minerals with black carbon. Based on Pb isotope analysis and air-mass backward trajectories, the dust in Daejeon received a considerable input of anthropogenic pollutants from heavily industrialized Chinese cities, which implies that long-range transported aerosols containing PbCrO4 were a possible source of the lead and hexavalent chromium levels in East Asia. Lead chromate should be considered to be a source of global atmospheric Pb and Cr(VI) pollution, especially given its toxicity.

  10. Lead chromate detected as a source of atmospheric Pb and Cr (VI) pollution.

    Science.gov (United States)

    Lee, Pyeong-Koo; Yu, Soonyoung; Chang, Hye Jung; Cho, Hye Young; Kang, Min-Ju; Chae, Byung-Gon

    2016-10-25

    Spherical black carbon aggregates were frequently observed in dust dry deposition in Daejeon, Korea. They were tens of micrometers in diameter and presented a mixture of black carbon and several mineral phases. Transmission electron microscopy (TEM) observations with energy-dispersive X-ray spectroscopy (EDS) and selected area diffraction pattern (SADP) analyses confirmed that the aggregates were compact and included significant amounts of lead chromate (PbCrO 4 ). The compositions and morphologies of the nanosized lead chromate particles suggest that they probably originated from traffic paint used in roads and were combined as discrete minerals with black carbon. Based on Pb isotope analysis and air-mass backward trajectories, the dust in Daejeon received a considerable input of anthropogenic pollutants from heavily industrialized Chinese cities, which implies that long-range transported aerosols containing PbCrO 4 were a possible source of the lead and hexavalent chromium levels in East Asia. Lead chromate should be considered to be a source of global atmospheric Pb and Cr(VI) pollution, especially given its toxicity.

  11. Curcumin Attenuates Hepatotoxicity Induced by Zinc Oxide Nanoparticles in Rats

    Directory of Open Access Journals (Sweden)

    Layasadat Khorsandi

    2016-06-01

    Full Text Available Background: Zinc oxide nanoparticles (NZnO are increasingly used in modern life. Most metal nanoparticles have adverse effects on the liver. Aims: To explore the protective action of curcumin (Cur against hepatotoxicity induced by NZnO in rats. Study Design: Animal experimentation. Methods: Control group animals received normal saline, while the Cur group animals were treated with 200 mg/kg of Cur orally for 21 days. NZnO-intoxicated rats received 50 mg/kg of NZnO for 14 days by gavage method. In the NZnO+Cur group, rats were pretreated with Cur for 7 days before NZnO administration. Plasma activities of Alanine aminotransferase (ALT, aspartate aminotransferase (AST and alkaline phosphatase (ALP were measured as biomarkers of hepatotoxicity. Hepatic levels of malondialdehyde (MDA and superoxide dismutase (SOD and glutathione peroxidase (GPx activities were measured for detection of oxidative stress in liver tissue. Histological changes and apoptosis in liver tissue were studied by using Hematoxylin-eosin staining and the transferase dUTP nick end labeling (TUNEL method. Results: NZnO induced a significant increase in plasma AST (2.8-fold, ALT (2.7-fold and ALP (1.97-fold activity in comparison to the control group (p<0.01. NZnO increased MDA content and reduced SOD and GPx activities. NZnO caused liver damage including centrilobular necrosis and microvesicular steatosis. The percentage of apoptosis in hepatocytes was increased in NZnO-treated rats (p<0.01. Pre-treatment of Cur significantly reduced lipid peroxidation (39%, increased SOD (156% and GPx (26% activities, and attenuated ALT (47%, AST (41% and ALP (30% activities. Pre-treatment with Cur also decreased the histology changes and apoptotic index of hepatocytes (p<0.05. Conclusion: These findings indicate that Cur effectively protects against NZnO-induced hepatotoxicity in rats. However, future studies are required to propose Cur as a potential protective agent against hepatotoxicity

  12. Assessment of Rod, Cone, and Intrinsically Photosensitive Retinal Ganglion Cell Contributions to the Canine Chromatic Pupillary Response.

    Science.gov (United States)

    Yeh, Connie Y; Koehl, Kristin L; Harman, Christine D; Iwabe, Simone; Guzman, José M; Petersen-Jones, Simon M; Kardon, Randy H; Komáromy, András M

    2017-01-01

    The purpose of this study was to evaluate a chromatic pupillometry protocol for specific functional assessment of rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) in dogs. Chromatic pupillometry was tested and compared in 37 dogs in different stages of primary loss of rod, cone, and combined rod/cone and optic nerve function, and in 5 wild-type (WT) dogs. Eyes were stimulated with 1-s flashes of dim (1 cd/m2) and bright (400 cd/m2) blue light (for scotopic conditions) or bright red (400 cd/m2) light with 25-cd/m2 blue background (for photopic conditions). Canine retinal melanopsin/Opn4 was cloned, and its expression was evaluated using real-time quantitative reverse transcription-PCR and immunohistochemistry. Mean ± SD percentage of pupil constriction amplitudes induced by scotopic dim blue (scDB), scotopic bright blue (scBB), and photopic bright red (phBR) lights in WT dogs were 21.3% ± 10.6%, 50.0% ± 17.5%, and 19.4% ± 7.4%, respectively. Melanopsin-mediated responses to scBB persisted for several minutes (7.7 ± 4.6 min) after stimulus offset. In dogs with inherited retinal degeneration, loss of rod function resulted in absent scDB responses, followed by decreased phBR responses with disease progression and loss of cone function. Primary loss of cone function abolished phBR responses but preserved those responses to blue light (scDB and scBB). Although melanopsin/Opn4 expression was diminished with retinal degeneration, melanopsin-expressing ipRGCs were identified for the first time in both WT and degenerated canine retinas. Pupil responses elicited by light stimuli of different colors and intensities allowed differential functional assessment of canine rods, cones, and ipRGCs. Chromatic pupillometry offers an effective tool for diagnosing retinal and optic nerve diseases.

  13. Amino-functionalized MCM-41 and MCM-48 for the removal of chromate and arsenate.

    Science.gov (United States)

    Benhamou, A; Basly, J P; Baudu, M; Derriche, Z; Hamacha, R

    2013-08-15

    The aim of the present work was to investigate the efficiency of three amino-functionalized (hexadecylamine, dodecylamine, and dimethyldodecylamine) mesoporous silicas (MCM-41 and MCM-48) toward the adsorption of arsenate and chromate. Hexadecylamine-functionalized materials were characterized; BET surface areas, pore volumes, and sizes decreased with the functionalization, whereas XRD patterns show that the hexagonal structure of MCM-41 and the cubic structure of MCM-48 were not modified. The zeta potential decreases with pH and the highest arsenate and chromate removal was observed at the lowest pHs. Adsorption of chromium and arsenate was significantly enhanced after functionalization and amino-functionalized MCM-41 adsorb larger amounts of arsenate when compared to expanded MCM-48 materials. Chromate sorption capacities increased with the chain length and the larger capacities were obtained with hexadecylamine-functionalized mesoporous silicas. Mesoporous silicas modified by dimethyldodecylamine exhibited the higher arsenate sorption capacities. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Reduced Chromatic Discrimination in Children with Autism Spectrum Disorders

    Science.gov (United States)

    Franklin, Anna; Sowden, Paul; Notman, Leslie; Gonzalez-Dixon, Melissa; West, Dorotea; Alexander, Iona; Loveday, Stephen; White, Alex

    2010-01-01

    Atypical perception in Autism Spectrum Disorders (ASD) is well documented (Dakin & Frith, 2005). However, relatively little is known about colour perception in ASD. Less accurate performance on certain colour tasks has led some to argue that chromatic discrimination is reduced in ASD relative to typical development (Franklin, Sowden, Burley,…

  15. Shock-induced fast reactions of zinc nanoparticles and RDX

    Energy Technology Data Exchange (ETDEWEB)

    Xue Mian; Wu Jinghe; Ye Song; Yang Xiangdong [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Hu Dong; Wang Yanping; Zhu Wenjun; Li Chengbing [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, CAEP, Mianyang 621900 (China)], E-mail: mi-anxue@163.com

    2008-02-21

    Fast reactions of zinc nanoparticles and RDX were investigated in normal incident shock waves. The emergence time and emission spectra intensity of partial products such as NO{sub 2}, H, C{sub 2}, O, CO, CH{sub 2}O, CO{sub 2}, H{sub 2}O and ZnO were observed by a TDS5054 oscilloscope. The results indicate that NO{sub 2} appears first in each experiment, which is in agreement with the theoretical results. The addition of zinc nanoparticles to RDX can not only shorten the ignition delay time by 20% but also double the shockwave diffusion velocity to 2180 {+-} 50 m s{sup -1} and triple the temperature to 2020 {+-} 60 K. The emergence time of products shortens by around 10-40% and the emission spectra intensity of H{sub 2}O and CH{sub 2}O rises by about three times and one times, respectively. CO{sub 2}, H{sub 2}O and O{sub 2} in various concentrations were introduced into the zinc-RDX reaction, respectively, which indicate that O{sub 2} made the ignition delay time shorten by over 30%, the effect of H{sub 2}O was not prominent while CO{sub 2} made the ignition delay time lag by around 30%. The results indicate that the Zn-O{sub 2} reaction mainly occurs in O{sub 2}, CO{sub 2} and H{sub 2}O.

  16. Determination of aluminium and beryllium by diffuse reflectance spectrometry with the use of chromaticity functions

    International Nuclear Information System (INIS)

    Ivanov, V.M.; Ershova, N.I.

    2001-01-01

    Immobilized Eriochrome Cyanine R was used for the direct trace determination of aluminium and beryllium by diffuse reflectance spectrometry. Anion exchanger AV-17, silica gel Silochrom C-120, Chromaton N-Super, silica gel C 18 , and cellulose were examined as supports. Optimal sorption conditions were found. The dependence of chromaticity functions (chromaticity coordinates, lightness, color saturation, yellowness, and whiteness) on different factors was studied. Advantages of the use of chromaticity functions rather than the diffuse reflectance coefficient were demonstrated. A method is developed for the separate determination of aluminium and beryllium using cellulose as the support; the method was used for the analysis of real samples and tested with standard samples. When solution samples of 50 and 100 ml were used, the determination limit was 0.004 μg/ml for aluminium and 0.0002 μg/ml for beryllium, respectively [ru

  17. Zinc and glutamate dehydrogenase in putative glutamatergic brain structures.

    Science.gov (United States)

    Wolf, G; Schmidt, W

    1983-01-01

    A certain topographic parallelism between the distribution of histochemically (TIMM staining) identified zinc and putative glutamatergic structures in the rat brain was demonstrated. Glutamate dehydrogenase as a zinc containing protein is in consideration to be an enzyme synthesizing transmitter glutamate. In a low concentration range externally added zinc ions (10(-9) to 10(-7) M) induced an increase in the activity of glutamate dehydrogenase (GDH) originating from rat hippocampal formation, neocortex, and cerebellum up to 142.4%. With rising molarity of Zn(II) in the incubation medium, the enzyme of hippocampal formation and cerebellum showed a biphasic course of activation. Zinc ions of a concentration higher than 10(-6) M caused a strong inhibition of GDH. The effect of Zn(II) on GDH originating from spinal ganglia and liver led only to a decrease of enzyme activity. These results are discussed in connection with a functional correlation between zinc and putatively glutamatergic system.

  18. Mechanisms and fitness implications of photomorphogenesis during chromatic acclimation in cyanobacteria.

    Science.gov (United States)

    Montgomery, Beronda L

    2016-07-01

    Photosynthetic organisms absorb photons and convert light energy to chemical energy through the process of photosynthesis. Photosynthetic efficiency is tuned in response to the availability of light, carbon dioxide and nutrients to promote maximal levels of carbon fixation, while simultaneously limiting the potential for light-associated damage or phototoxicity. Given the central dependence on light for energy production, photosynthetic organisms possess abilities to tune their growth, development and metabolism to external light cues in the process of photomorphogenesis. Photosynthetic organisms perceive light intensity and distinct wavelengths or colors of light to promote organismal acclimation. Cyanobacteria are oxygenic photosynthetic prokaryotes that exhibit abilities to alter specific aspects of growth, including photosynthetic pigment composition and morphology, in responses to changes in available wavelengths and intensity of light. This form of photomorphogenesis is known as chromatic acclimation and has been widely studied. Recent insights into the photosensory photoreceptors found in cyanobacteria and developments in our understanding of the molecular mechanisms initiated by light sensing to affect the changes characteristic of chromatic acclimation are discussed. I consider cyanobacterial responses to light, the broad diversity of photoreceptors encoded by these organisms, specific mechanisms of photomorphogenesis, and associated fitness implications in chromatically acclimating cyanobacteria. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Chelation in metal intoxication. VIII. Removal of chromium from organs of potassium chromate administered rats.

    Science.gov (United States)

    Behari, J R; Tandon, S K

    1980-03-01

    Some polyaminocarboxylic acids were examined for their ability to mobilize chromium from certain vital organs, their subcellular fractions, and blood cells of potassium chromate administered rats. Hexamethylene 1,6-diamino tetraacetic acid (TDTA), triethylene tetramine hexaacetic acid (TTHA), and ethylene diamine di (O-hydroxylphenyl acetic acid) (EDDHA) may be useful in preventing or reducing chromate toxicity. No definite relationship could be observed between the structure of the chelating agents and their chromium-removing capacity.

  20. Methods and optical fibers that decrease pulse degradation resulting from random chromatic dispersion

    Science.gov (United States)

    Chertkov, Michael; Gabitov, Ildar

    2004-03-02

    The present invention provides methods and optical fibers for periodically pinning an actual (random) accumulated chromatic dispersion of an optical fiber to a predicted accumulated dispersion of the fiber through relatively simple modifications of fiber-optic manufacturing methods or retrofitting of existing fibers. If the pinning occurs with sufficient frequency (at a distance less than or are equal to a correlation scale), pulse degradation resulting from random chromatic dispersion is minimized. Alternatively, pinning may occur quasi-periodically, i.e., the pinning distance is distributed between approximately zero and approximately two to three times the correlation scale.

  1. Differential algebraic method for arbitrary order curvilinear-axis combined geometric-chromatic aberration analysis

    International Nuclear Information System (INIS)

    Cheng Min; Tang Tiantong; Lu Yilong; Yao Zhenhua

    2003-01-01

    The principle of differential algebra is applied to analyse and calculate arbitrary order curvilinear-axis combined geometric-chromatic aberrations of electron optical systems. Expressions of differential algebraic form of high order combined aberrations are obtained and arbitrary order combined aberrations can be calculated numerically. As an example, a typical wide electron beam focusing system with curved optical axes named magnetic immersion lens has been studied. All the second-order and third-order combined geometric-chromatic aberrations of the lens have been calculated, and the patterns of the corresponding geometric aberrations and combined aberrations have been given as well

  2. New chromaticity compensation approach and dynamic aperture increase in the SSRF storage ring

    International Nuclear Information System (INIS)

    Tian Shunqiang; Hou Jie; Chen Guangling; Chinese Academy of Sciences, Beijing; Liu Guimin

    2008-01-01

    Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically. Many optimization methods can be used to find solutions that provide large dynamic apertures. This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure, which is applied in the SSRF storage ring, and a better solution is obtained. Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory. (authors)

  3. Half-metallic ferromagnetism in Cu-doped zinc-blende ZnO from first principles study

    International Nuclear Information System (INIS)

    Li, X.F.; Zhang, J.; Xu, B.; Yao, K.L.

    2012-01-01

    Electronic structures and magnetism of Cu-doped zinc-blende ZnO have been investigated by the first-principle method based on density functional theory (DFT). The results show that Cu can induce stable ferromagnetic ground state. The magnetic moment of supercell including single Cu atom is 1.0 μ B . Electronic structure shows that Cu-doped zinc-blende ZnO is a p-type half-metallic ferromagnet. The half-metal property is mainly attribute to the crystal field splitting of Cu 3d orbital, and the ferromagnetism is dominated by the hole-mediated double exchange mechanism. Therefore, Cu-doped zinc-blende ZnO should be useful in semiconductor spintronics and other applications. - Highlights: → Magnetism of Cu-doped zinc-blende ZnO. → Cu-doped zinc-blende ZnO shows interesting half-metal character. → Total energies calculations reveal that Cu can induce ferromagnetic ground state. → Ferromagnetism dominated by the hole-mediated double exchange mechanism.

  4. Green Synthesized Zinc Oxide (ZnO) Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System.

    Science.gov (United States)

    Panda, Kamal K; Golari, Dambaru; Venugopal, A; Achary, V Mohan M; Phaomei, Ganngam; Parinandi, Narasimham L; Sahu, Hrushi K; Panda, Brahma B

    2017-05-18

    Zinc oxide nanoparticles (ZnONP-GS) were synthesised from the precursor zinc acetate (Zn(CH₃COO)₂) through the green route using the milky latex from milk weed ( Calotropis gigantea L. R. Br) by alkaline precipitation. Formation of the ZnONP-GS was monitored by UV-visible spectroscopy followed by characterization and confirmation by energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Both the ZnONP-GS and the commercially available ZnONP-S (Sigma-Aldrich) and cationic Zn 2+ from Zn(CH₃COO)₂ were tested in a dose range of 0-100 mg·L -1 for their potency (i) to induce oxidative stress as measured by the generation reactive oxygen species (ROS: O₂ •- , H₂O₂ and • OH), cell death, and lipid peroxidation; (ii) to modulate the activities of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), guaiacol peroxidase (GPX), and ascorbate peroxidase (APX); and (iii) to cause DNA damage as determined by Comet assay in Lathyrus sativus L. root bioassay system. Antioxidants such as Tiron and dimethylthiourea significantly attenuated the ZnONP-induced oxidative and DNA damage, suggesting the involvement of ROS therein. Our study demonstrated that both ZnONP-GS and ZnONP-S induced oxidative stress and DNA damage to a similar extent but were significantly less potent than Zn 2+ alone.

  5. Red light emission from europium doped zinc sodium bismuth borate glasses

    Science.gov (United States)

    Hegde, Vinod; Viswanath, C. S. Dwaraka; Upadhyaya, Vyasa; Mahato, K. K.; Kamath, Sudha D.

    2017-12-01

    Zinc sodium bismuth borate (ZNBB) glasses doped with different concentrations of europium were prepared by conventional melt quenching method and characterized through the measurements of density, refractive index, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectra, optical absorption, luminescence and radiative lifetimes. FTIR spectra showed seven characteristic peaks of bismuth and borate functional groups in the range of 400-1600 cm-1. The optical band gap and bonding parameters have been calculated from absorption spectra. Photoluminescence spectra recorded in the visible region with 394 nm excitation are used to calculate the Judd-Ofelt (JO) intensity parameters (Ω2 and Ω4). The JO intensity parameters have been used to calculate the radiative parameters such as branching ratio (β), stimulated emission cross-section (σse), transition probability (A) for the fluorescent level of 5D0→7F2. Decay rates through single exponential are used to calculate the lifetime (τm) of the meta-stable state 5D0 of (Eu3+ ion) these glasses. The radiative parameters measured for all these glasses show 0.7 mol% europium doped zinc sodium bismuth borate glass 5D0→7F2 transition has the potential for red laser applications. The quality of the colour emitted by the present glasses are estimated quantitatively by CIE chromaticity coordinates, which confirms the suitability of these glasses as a red emitting material for field emission technologies and LEDs.

  6. Analysis of transverse RMS emittance growth of a beam induced by spherical and chromatic aberration in a solenoidal field

    Energy Technology Data Exchange (ETDEWEB)

    Dash, Radhakanta, E-mail: radhakanta.physics@gmail.com [Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India); Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Nayak, Biswaranjan [Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India); Sharma, Archana; Mittal, Kailash C. [Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094 (India); Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2016-01-21

    In a medium energy beam transport line transverse rms emittance growth associated with spherical aberration is analysed. An analytical expression is derived for beam optics in a solenoid field considering terms up to the third order in the radial displacement. Two important phenomena: effect of spherical aberrations in axial-symmetric focusing lens and influence of nonlinear space charge forces on beam emittance growth are discussed for different beam distributions. In the second part nonlinear effect associated with chromatic aberration that describes the growth of emittance and distortion of phase space area is discussed.

  7. Corrosion and protection of uranium alloy penetrators

    International Nuclear Information System (INIS)

    Weirick, L.J.; Johnson, H.R.; Dini, J.W.

    1975-06-01

    Penetrators made from either a U--3/4 percent Ti alloy or a U--3/4 percent Mo--3/4 percent Zr--3/4 percent Nb--1/2 percent Ti alloy (''Quad'') corrode mildly in moist air, significantly in moist nitrogen, and severely in salt fog. Adequate protection was provided in moist air and nitrogen by coating with electroplated nickel, electroplated nickel and zinc with a chromate finish, and galvanized zinc with a chromate finish. In salt fog, electroplated nickel offered only temporary protection whereas galvanized zinc and electroplated nickel-zinc provided long-lasting protection. The resistance of uncoated penetrators was affected variously by dissimilar metal couplings. Aluminum protected the Quad alloy and adversely affected the U--3/4 percent Ti alloy, whereas steel enhanced localized corrosion in both. (U.S.)

  8. Does the oral zinc tolerance test measure zinc absorption

    Energy Technology Data Exchange (ETDEWEB)

    Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.

    1985-01-01

    Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi /sup 65/ZnCl/sub 2/ and a non-absorbed marker, /sup 51/CrCl/sub 3/, dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with /sup 65/Zn and /sup 51/Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and /sup 65/Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and /sup 65/Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption.

  9. Does the oral zinc tolerance test measure zinc absorption

    International Nuclear Information System (INIS)

    Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.

    1985-01-01

    Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi 65 ZnCl 2 and a non-absorbed marker, 51 CrCl 3 , dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with 65 Zn and 51 Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and 65 Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and 65 Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption

  10. Pursuit Latency for Chromatic Targets

    Science.gov (United States)

    Mulligan, Jeffrey B.; Ellis, Stephen R. (Technical Monitor)

    1998-01-01

    The temporal dynamics of eye movement response to a change in direction of stimulus motion has been used to compare the processing speeds of different types of stimuli (Mulligan, ARVO '97). In this study, the pursuit response to colored targets was measured to test the hypothesis that the slow response of the chromatic system (as measured using traditional temporal sensitivity measures such as contrast sensitivity) results in increased eye movement latencies. Subjects viewed a small (0.4 deg) Gaussian spot which moved downward at a speed of 6.6 deg/sec. At a variable time during the trajectory, the dot's direction of motion changed by 30 degrees, either to the right or left. Subjects were instructed to pursue the spot. Eye movements were measured using a video ophthalmoscope with an angular resolution of approximately 1 arc min and a temporal sampling rate of 60 Hz. Stimuli were modulated in chrominance for a variety of hue directions, combined with a range of small luminance increments and decrements, to insure that some of the stimuli fell in the subjects' equiluminance planes. The smooth portions of the resulting eye movement traces were fit by convolving the stimulus velocity with an exponential having variable onset latency, time constant and amplitude. Smooth eye movements with few saccades were observed for all stimuli. Pursuit responses to stimuli having a significant luminance component are well-fit by exponentials having latencies and time constants on the order of 100 msec. Increases in pursuit response latency on the order of 100-200 msec are observed in response to certain stimuli, which occur in pairs of complementary hues, corresponding to the intersection of the stimulus section with the subjects' equiluminant plane. Smooth eye movements can be made in response to purely chromatic stimuli, but are slower than responses to stimuli with a luminance component.

  11. A double-blind, randomized study comparing pure chromated glycerin with chromated glycerin with 1% lidocaine and epinephrine for sclerotherapy of telangiectasias and reticular veins.

    Science.gov (United States)

    Kern, Philippe; Ramelet, Albert-Adrien; Wutschert, Robert; Mazzolai, Lucia

    2011-11-01

    Chromated glycerin (CG) is an effective, although painful, sclerosing agent for telangiectasias and reticular leg veins treatment. To determine pain level and relative efficacy of pure or one-third lidocaine-epinephrine 1% mixed chromated glycerin in a prospective randomized double-blind trial. Patients presenting with telangiectasias and reticular leg veins on the lateral aspect of the thigh (C(1A) or (S) E(P) A(S) P(N1) ) were randomized to receive pure CG or CG mixed with one-third lidocaine-epinephrine 1% (CGX) treatment. Lower limb photographs were taken before and after treatment and analyzed by blinded expert reviewers for efficacy assessment (visual vein disappearance). Patients' pain and satisfaction were assessed using visual analogue scales. Data from 102 of 110 randomized patients could be evaluated. Patient pain scores were significantly higher when pure CG was used than with CGX (psclerotherapy pain without affecting efficacy when treating telangiectasias and reticular leg veins. © 2011 by the American Society for Dermatologic Surgery, Inc.

  12. Joint denoising, demosaicing, and chromatic aberration correction for UHD video

    Science.gov (United States)

    Jovanov, Ljubomir; Philips, Wilfried; Damstra, Klaas Jan; Ellenbroek, Frank

    2017-09-01

    High-resolution video capture is crucial for numerous applications such as surveillance, security, industrial inspection, medical imaging and digital entertainment. In the last two decades, we are witnessing a dramatic increase of the spatial resolution and the maximal frame rate of video capturing devices. In order to achieve further resolution increase, numerous challenges will be facing us. Due to the reduced size of the pixel, the amount of light also reduces, leading to the increased noise level. Moreover, the reduced pixel size makes the lens imprecisions more pronounced, which especially applies to chromatic aberrations. Even in the case when high quality lenses are used some chromatic aberration artefacts will remain. Next, noise level additionally increases due to the higher frame rates. To reduce the complexity and the price of the camera, one sensor captures all three colors, by relying on Color Filter Arrays. In order to obtain full resolution color image, missing color components have to be interpolated, i.e. demosaicked, which is more challenging than in the case of lower resolution, due to the increased noise and aberrations. In this paper, we propose a new method, which jointly performs chromatic aberration correction, denoising and demosaicking. By jointly performing the reduction of all artefacts, we are reducing the overall complexity of the system and the introduction of new artefacts. In order to reduce possible flicker we also perform temporal video enhancement. We evaluate the proposed method on a number of publicly available UHD sequences and on sequences recorded in our studio.

  13. Influence of DNA-methylation on zinc homeostasis in myeloid cells: Regulation of zinc transporters and zinc binding proteins.

    Science.gov (United States)

    Kessels, Jana Elena; Wessels, Inga; Haase, Hajo; Rink, Lothar; Uciechowski, Peter

    2016-09-01

    The distribution of intracellular zinc, predominantly regulated through zinc transporters and zinc binding proteins, is required to support an efficient immune response. Epigenetic mechanisms such as DNA methylation are involved in the expression of these genes. In demethylation experiments using 5-Aza-2'-deoxycytidine (AZA) increased intracellular (after 24 and 48h) and total cellular zinc levels (after 48h) were observed in the myeloid cell line HL-60. To uncover the mechanisms that cause the disturbed zinc homeostasis after DNA demethylation, the expression of human zinc transporters and zinc binding proteins were investigated. Real time PCR analyses of 14 ZIP (solute-linked carrier (SLC) SLC39A; Zrt/IRT-like protein), and 9 ZnT (SLC30A) zinc transporters revealed significantly enhanced mRNA expression of the zinc importer ZIP1 after AZA treatment. Because ZIP1 protein was also enhanced after AZA treatment, ZIP1 up-regulation might be the mediator of enhanced intracellular zinc levels. The mRNA expression of ZIP14 was decreased, whereas zinc exporter ZnT3 mRNA was also significantly increased; which might be a cellular reaction to compensate elevated zinc levels. An enhanced but not significant chromatin accessibility of ZIP1 promoter region I was detected by chromatin accessibility by real-time PCR (CHART) assays after demethylation. Additionally, DNA demethylation resulted in increased mRNA accumulation of zinc binding proteins metallothionein (MT) and S100A8/S100A9 after 48h. MT mRNA was significantly enhanced after 24h of AZA treatment also suggesting a reaction of the cell to restore zinc homeostasis. These data indicate that DNA methylation is an important epigenetic mechanism affecting zinc binding proteins and transporters, and, therefore, regulating zinc homeostasis in myeloid cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

  14. A bipyridine-ligated zinc(II) complex with bridging flavonolate ligation: synthesis, characterization, and visible-light-induced CO release reactivity.

    Science.gov (United States)

    Sorenson, Shayne; Popova, Marina; Arif, Atta M; Berreau, Lisa M

    2017-09-01

    Metal-flavonolate compounds are of significant current interest as synthetic models for quercetinase enzymes and as bioactive compounds of importance to human health. Zinc-3-hydroxyflavonolate compounds, including those of quercetin, kampferol, and morin, generally exhibit bidentate coordination to a single Zn II center. The bipyridine-ligated zinc-flavonolate compound reported herein, namely bis(μ-4-oxo-2-phenyl-4H-chromen-3-olato)-κ 3 O 3 :O 3 ,O 4 ;κ 3 O 3 ,O 4 :O 3 -bis[(2,2'-bipyridine-κ 2 N,N')zinc(II)] bis(perchlorate), {[Zn 2 (C 15 H 9 O 3 ) 2 (C 10 H 8 N 2 ) 2 ](ClO 4 ) 2 } n , (1), provides an unusual example of bridging 3-hydroxyflavonolate ligation in a dinuclear metal complex. The symmetry-related Zn II centers of (1) exhibit a distorted octahedral geometry, with weak coordination of a perchlorate anion trans to the bridging deprotonated O atom of the flavonolate ligand. Variable-concentration conductivity measurements provide evidence that, when (1) is dissolved in CH 3 CN, the complex dissociates into monomers. 1 H NMR resonances for (1) dissolved in d 6 -DMSO were assigned via HMQC to the H atoms of the flavonolate and bipyridine ligands. In CH 3 CN, (1) undergoes quantitative visible-light-induced CO release with a quantum yield [0.004 (1)] similar to that exhibited by other mononuclear zinc-3-hydroxyflavonolate complexes. Mass spectroscopic identification of the [(bpy) 2 Zn(O-benzoylsalicylate)] + ion provides evidence of CO release from the flavonol and of ligand exchange at the Zn II center.

  15. Molecular basis of chromatic adaptation in pennate diatom Phaeodactylum tricornutum

    Czech Academy of Sciences Publication Activity Database

    Herbstová, Miroslava; Bína, David; Koník, P.; Gardian, Zdenko; Vácha, František; Litvín, Radek

    2015-01-01

    Roč. 1847, 6-7 (2015), s. 534-543 ISSN 0005-2728 R&D Projects: GA ČR GBP501/12/G055 Institutional support: RVO:60077344 Keywords : Chromatic adaptation * Diatom * Heterokonta * Light harvesting antenna Subject RIV: CE - Biochemistry Impact factor: 4.864, year: 2015

  16. Totally odd K-4-subdivisions in 4-chromatic graphs

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2001-01-01

    We prove the conjecture made by Bjarne Toft in 1975 that every 4-chromatic graph contains a subdivision of K-4 in which each edge of K-4 corresponds to a path of odd length. As an auxiliary result we characterize completely the subspace of the cycle space generated by all cycles through two fixed...

  17. Differential sensitivities of cellular XPA and PARP-1 to arsenite inhibition and zinc rescue.

    Science.gov (United States)

    Ding, Xiaofeng; Zhou, Xixi; Cooper, Karen L; Huestis, Juliana; Hudson, Laurie G; Liu, Ke Jian

    2017-09-15

    Arsenite directly binds to the zinc finger domains of the DNA repair protein poly (ADP ribose) polymerase (PARP)-1, and inhibits PARP-1 activity in the base excision repair (BER) pathway. PARP inhibition by arsenite enhances ultraviolet radiation (UVR)-induced DNA damage in keratinocytes, and the increase in DNA damage is reduced by zinc supplementation. However, little is known about the effects of arsenite and zinc on the zinc finger nucleotide excision repair (NER) protein xeroderma pigmentosum group A (XPA). In this study, we investigated the difference in response to arsenite exposure between XPA and PARP-1, and the differential effectiveness of zinc supplementation in restoring protein DNA binding and DNA damage repair. Arsenite targeted both XPA and PARP-1 in human keratinocytes, resulting in zinc loss from each protein and a pronounced decrease in XPA and PARP-1 binding to chromatin as demonstrated by Chip-on-Western assays. Zinc effectively restored DNA binding of PARP-1 and XPA to chromatin when zinc concentrations were equal to those of arsenite. In contrast, zinc was more effective in rescuing arsenite-augmented direct UVR-induced DNA damage than oxidative DNA damage. Taken together, our findings indicate that arsenite interferes with PARP-1 and XPA binding to chromatin, and that zinc supplementation fully restores DNA binding activity to both proteins in the cellular context. Interestingly, rescue of arsenite-inhibited DNA damage repair by supplemental zinc was more sensitive for DNA damage repaired by the XPA-associated NER pathway than for the PARP-1-dependent BER pathway. This study expands our understanding of arsenite's role in DNA repair inhibition and co-carcinogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Zinc-induced differential oxidative stress and antioxidant responses in Chlorella sorokiniana and Scenedesmus acuminatus.

    Science.gov (United States)

    Hamed, Seham M; Zinta, Gaurav; Klöck, Gerd; Asard, Han; Selim, Samy; AbdElgawad, Hamada

    2017-06-01

    Algae are frequently exposed to toxic metals, and zinc (Zn) is one of the major toxicants present. We exposed two green microalgae, Chlorella sorokiniana and Scenedesmus acuminatus, to sub-lethal concentrations (1.0 and 0.6mM) of Zn for seven days. Algal responses were analysed at the level of growth, oxidative stress, and antioxidants. Growth parameters such as cell culture yield and pigment content were less affected by Zn in C. sorokiniana, despite the fact that this alga accumulated more zinc than S. acuminatus. Also, C. sorokiniana, but not S. acuminatus, was able to acclimatize during long-term exposure to toxic concentrations of the test metals (specific growth rate (µ) was 0.041/day and total chlorophyll was 14.6mg/mL). Although, Zn induced oxidative stress in both species, C. sorokiniana experienced less stress than S. acuminatus. This could be explained by a higher accumulation of antioxidants in C. sorokiniana, where flavonoids, polyphenols, tocopherols, glutathione (GSH) and ascorbate (ASC) content increased. Moreover, antioxidant enzymes glutathione S transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX), showed increased activities in C. sorokiniana. In addition to, and probably also underlying, the higher Zn tolerance in C. sorokiniana, this alga also showed higher Zn biosorption capacity. Use of C. sorokiniana as a bio-remediator, could be considered. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Method of capturing or trapping zinc using zinc getter materials

    Science.gov (United States)

    Hunyadi Murph, Simona E.; Korinko, Paul S.

    2017-07-11

    A method of trapping or capturing zinc is disclosed. In particular, the method comprises a step of contacting a zinc vapor with a zinc getter material. The zinc getter material comprises nanoparticles and a metal substrate.

  20. Erythrocyte metallothionein as an index of zinc status in humans

    International Nuclear Information System (INIS)

    Grider, A.; Bailey, L.B.; Cousins, R.J.

    1990-01-01

    Metallothionein concentrations in erythrocyte lysates derived from human subjects were measured by an ELISA procedure. IgG obtained from serum of sheep injected with human metallothionein 1 was used in this competitive assay. Subjects were fed a semipurified zinc-deficient diet for an 8-day depletion period after 3 days of acclimation. Fasting plasma zinc concentrations were reduced ∼7%. Metallothionein in the erythrocyte lysates was significantly decreased to 59% of the initial level by the end of the depletion period. Supplementation of these depleted subjects with zinc did not increase erythrocyte metallothionein levels within 24 hr. Daily supplementation of control subjects with zinc increased erythrocyte metallothionein to a 7-fold maximum within 7 days. These levels were reduced by 61% within 14 days after zinc supplementation was terminated. Incubation of rat [ 35 S]metallothionein with human erythrocyte lysate showed a time-dependent increase in 35 S soluble in 20% trichloroacetic acid, indicating degradation of the labeled protein, presumably via protease activity in the lysate. It is proposed that zinc supplementation induces erythrocyte metallothionein during erythropoiesis and that low zinc intake decreases synthesis and/or accelerates degradation of the protein in reticulocytes/erythrocytes. Metallothionein levels in erythrocytes may provide a useful index upon which to assess zinc status in humans

  1. Chromatic monitoring of dc plasma torches: The latest developments

    Czech Academy of Sciences Publication Activity Database

    Djakov, B. E.; Enikov, R.; Oliver, D.H.; Hrabovský, Milan; Kopecký, Vladimír

    2006-01-01

    Roč. 3, č. 2 (2006), s. 170-173 ISSN 1612-8850 R&D Projects: GA ČR(CZ) GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : chromatic monitoring * on-line control * plasma jet * plasma torch * powder Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.298, year: 2006

  2. The chromatic correction in RHIC [Relativistic Heavy Ion Collider

    International Nuclear Information System (INIS)

    Lee, S.Y.; Dell, G.F.; Hahn, H.; Parzen, G.

    1987-01-01

    The scheme for the correction of chromatic effects in the Relativistic Heavy Ion Collider at BNL is discussed. This scheme uses six families of sextupoles excited by four independent power supplies, and provides adequate control of linear and quadratic terms in the tune vs momentum dependence and reduces the variation of the betatron amplitude, vs momentum

  3. Zinc transporter ZIP14 functions in hepatic zinc, iron and glucose homeostasis during the innate immune response (endotoxemia.

    Directory of Open Access Journals (Sweden)

    Tolunay Beker Aydemir

    Full Text Available ZIP14 (slc39A14 is a zinc transporter induced in response to pro-inflammatory stimuli. ZIP14 induction accompanies the reduction in serum zinc (hypozincemia of acute inflammation. ZIP14 can transport Zn(2+ and non-transferrin-bound Fe(2+ in vitro. Using a Zip14(-/- mouse model we demonstrated that ZIP14 was essential for control of phosphatase PTP1B activity and phosphorylation of c-Met during liver regeneration. In the current studies, a global screening of ZIP transporter gene expression in response to LPS-induced endotoxemia was conducted. Following LPS, Zip14 was the most highly up-regulated Zip transcript in liver, but also in white adipose tissue and muscle. Using ZIP14(-/- mice we show that ZIP14 contributes to zinc absorption from the gastrointestinal tract directly or indirectly as zinc absorption was decreased in the KOs. In contrast, Zip14(-/- mice absorbed more iron. The Zip14 KO mice did not exhibit hypozincemia following LPS, but do have hypoferremia. Livers of Zip14-/- mice had increased transcript abundance for hepcidin, divalent metal transporter-1, ferritin and transferrin receptor-1 and greater accumulation of iron. The Zip14(-/- phenotype included greater body fat, hypoglycemia and higher insulin levels, as well as increased liver glucose and greater phosphorylation of the insulin receptor and increased GLUT2, SREBP-1c and FASN expression. The Zip14 KO mice exhibited decreased circulating IL-6 with increased hepatic SOCS-3 following LPS, suggesting SOCS-3 inhibited insulin signaling which produced the hypoglycemia in this genotype. The results are consistent with ZIP14 ablation yielding abnormal labile zinc pools which lead to increased SOCS-3 production through G-coupled receptor activation and increased cAMP production as well as signaled by increased pSTAT3 via the IL-6 receptor, which inhibits IRS 1/2 phosphorylation. Our data show the role of ZIP14 in the hepatocyte is multi-functional since zinc and iron trafficking are

  4. Interleukin 6 regulates metallothionein gene expression and zinc metabolism in hepatocyte monolayer cultures

    International Nuclear Information System (INIS)

    Schroeder, J.J.; Cousins, R.J.

    1990-01-01

    Attention has focused on the cytokine interleukin 6 (IL-6) as a major mediator of acute-phase protein synthesis in hepatocytes in response to infection and tissue injury. The authors have evaluated the effects of IL-6 and IL-1α as well as extracellular zinc and glucocorticoid hormone on metal-lothionein gene expression and cellular zinc accumulation in rat hepatocyte monolayer cultures. Further, they have evaluated the teleological basis for cytokine mediation by examining cyto-protection from CCl 4 -induced damage. Incubation of hepatocytes with IL-6 led to concentration-dependent and time-dependent increases in metallothionein-1 and -2 mRNA and metallothionein protein. The level of each was increased within 3 hr after the addition of IL-6 at 10 ng/ml. Maximal increases the metallothionein mRNA and metallothionein protein were achieved after 12 hr and 36 hr, respectively. Concomitant with the up-regulation of metallothionein gene expression, IL-6 also increased cellular zinc. Responses to IL-6 required the synthetic glucocorticoid hormone dexamethasone and were optimized by increased extracellular zinc. Thus, IL-6 is a major cytokine mediator of metallothionein gene expression and zinc metabolism in hepatocytes and provides cytoprotection from CCl 4 -induced hepatotoxicity via a mode consistent with dependence upon increased cellular metallothionein synthesis and zinc accumulation

  5. Electrochemical reduction of dilute chromate solutions on carbon felt electrodes

    NARCIS (Netherlands)

    Frenzel, Ines; Frenzel, I.; Holdik, Hans; Barmashenko, Vladimir; Stamatialis, Dimitrios; Wessling, Matthias

    2006-01-01

    Carbon felt is a potential material for electrochemical reduction of chromates. Very dilute solutions may be efficiently treated due to its large specific surface area and high porosity. In this work, the up-scaling of this technology is investigated using a new type of separated cell and

  6. A Normative Data Set for the Clinical Assessment of Achromatic and Chromatic Contrast Sensitivity Using a qCSF Approach.

    Science.gov (United States)

    Kim, Yeon Jin; Reynaud, Alexandre; Hess, Robert F; Mullen, Kathy T

    2017-07-01

    The measurement of achromatic sensitivity has been an important tool for monitoring subtle changes in vision as the result of disease or response to therapy. In this study, we aimed to provide a normative data set for achromatic and chromatic contrast sensitivity functions within a common cone contrast space using an abbreviated measurement approach suitable for clinical practice. In addition, we aimed to provide comparisons of achromatic and chromatic binocular summation across spatial frequency. We estimated monocular cone contrast sensitivity functions (CCSFs) using a quick Contrast Sensitivity Function (qCSF) approach for achromatic as well as isoluminant, L/M cone opponent, and S cone opponent stimuli in a healthy population of 51 subjects. We determined the binocular CCSFs for achromatic and chromatic vision to evaluate the degree of binocular summation across spatial frequency for these three different mechanisms in a subset of 20 subjects. Each data set shows consistent contrast sensitivity across the population. They highlight the extremely high cone contrast sensitivity of L/M cone opponency compared with the S-cone and achromatic responses. We also find that the two chromatic sensitivities are correlated across the healthy population. In addition, binocular summation for all mechanisms depends strongly on stimulus spatial frequency. This study, using an approach well suited to the clinic, is the first to provide a comparative normative data set for the chromatic and achromatic contrast sensitivity functions, yielding quantitative comparisons of achromatic, L/M cone opponent, and S cone opponent chromatic sensitivities as a function of spatial frequency.

  7. Detection of zinc translocation into apical dendrite of CA1 pyramidal neuron after electrical stimulation.

    Science.gov (United States)

    Suh, Sang Won

    2009-02-15

    Translocation of the endogenous cation zinc from presynaptic terminals to postsynaptic neurons after brain insult has been implicated as a potential neurotoxic event. Several studies have previously demonstrated that a brief electrical stimulation is sufficient to induce the translocation of zinc from presynaptic vesicles into the cytoplasm (soma) of postsynaptic neurons. In the present work I have extended those findings in three ways: (i) providing evidence that zinc translocation occurs into apical dendrites, (ii) presenting data that there is an apparent translocation into apical dendrites when only a zinc-containing synaptic input is stimulated, and (iii) presenting data that there is no zinc translocation into apical dendrite of ZnT3 KO mice following electrical stimulation. Hippocampal slices were preloaded with the "trappable" zinc fluorescent probe, Newport Green. After washout, a single apical dendrite in the stratum radiatum of hippocampal CA1 area was selected and focused on. Burst stimulation (100Hz, 500microA, 0.2ms, monopolar) was delivered to either the adjacent Schaffer-collateral inputs (zinc-containing) or to the adjacent temporo-ammonic inputs (zinc-free) to the CA1 dendrites. Stimulation of the Schaffer collaterals increased the dendritic fluorescence, which was blocked by TTX, low-Ca medium, or the extracellular zinc chelator, CaEDTA. Stimulation of the temporo-ammonic pathway caused no significant rise in the fluorescence. Genetic depletion of vesicular zinc by ZnT3 KO showed no stimulation-induced apical dendrite zinc rise. The present study provides evidence that synaptically released zinc translocates into postsynaptic neurons through the apical dendrites of CA1 pyramidal neurons during physiological synaptic activity.

  8. On Chromatic no. of 3K1-free graphs and R(3, k)

    OpenAIRE

    Dhurandhar, Medha S.

    2012-01-01

    Here we prove that if G has independence no. 2 and clique size omega with omega less than or equal to 11, then (1) chromatic no. is less than or equal to (omega2+12omega-13)/8, if omega is odd, and (2) chromatic no. is less than or equal to (omega2+10omega)/8, if omega is even. We further conjecture that the results are true in general for all omega. We also conjecture that (A) if omega is odd and R(3, omega) is even, then R(3, omega) = (omega2+8omega-9)/4, (B) if omega and R(3, omega) are bo...

  9. The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

    OpenAIRE

    Veldkamp, T.; Diepen, van, J.T.M.; Bikker, P.

    2014-01-01

    Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR Livestock Research to determine the bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens. A precise estimate of the bioavailability of zinc sources is required both for fulf...

  10. Syntheses and crystal structures of two novel alkaline uranyl chromates A2(UO2)(CrO4)2 (A=Rb, Cs) with bidentate coordination mode of uranyl ions by chromate anions

    International Nuclear Information System (INIS)

    Siidra, Oleg I.; Nazarchuk, Evgeny V.; Krivovichev, Sergey V.

    2012-01-01

    Single crystals of Cs 2 (UO 2 )(CrO 4 ) 2 and Rb 2 (UO 2 )(CrO 4 ) 2 were prepared by solid state reactions. The structures are based upon the [(UO 2 )(CrO 4 ) 2 ] 2− chains. Within the chains, UrO 5 pentagonal bipyramids (Ur=uranyl) form Ur 2 O 8 dimers, which are linked via CrO 4 tetrahedra into one-dimensional chains. The CrO 4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion, which is unusual for uranyl chromates. The bidentate coordination has a strong influence upon geometrical parameters of both U and Cr coordination polyhedra. The conformation of the chains in 1 and 2 is different due to the different size of the Cs + and Rb + cations. - Graphical abstract: Uranyl chromate chain with monodentate and bidentate coordination mode of uranyl cations by CrO 4 tetrahedra in Cs 2 (UO 2 )(CrO 4 ) 2 . Highlights: ► Single crystals of novel uranyl chromates were prepared by solid state reactions. ► The CrO 4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion. ►The bidentate coordination has a strong influence upon geometrical parameters.

  11. Experimental verification of the minimum number of diffractive zones for effective chromatic correction in the LWIR

    Science.gov (United States)

    Ramsey, J. L.; Walsh, K. F.; Smith, M.; Deegan, J.

    2016-05-01

    With the move to smaller pixel sizes in the longwave IR region there has been a push for shorter focal length lenses that are smaller, cheaper and lighter and that resolve lower spatial frequencies. As a result lenses must have better correction for both chromatic and monochromatic aberrations. This leads to the increased use of aspheres and diffractive optical elements (kinoforms). With recent developments in the molding of chalcogenide materials these aspheres and kinoforms are more cost effective to manufacture. Without kinoforms the axial color can be on the order of 15 μm which degrades the performance of the lens at the Nyquist frequency. The kinoforms are now on smaller elements and are correcting chromatic aberration which is on the order of the design wavelength. This leads to kinoform structures that do not require large phase changes and therefore have 1.5 to just over 2 zones. The question becomes how many zones are required to correct small amounts of chromatic aberration in the system and are they functioning as predicted by the lens design software? We investigate both the design performance and the as-built performance of two designs that incorporate kinoforms for the correction of axial chromatic aberration.

  12. Correcting for color crosstalk and chromatic aberration in multicolor particle shadow velocimetry

    International Nuclear Information System (INIS)

    McPhail, M J; Fontaine, A A; Krane, M H; Goss, L; Crafton, J

    2015-01-01

    Color crosstalk and chromatic aberration can bias estimates of fluid velocity measured by color particle shadow velocimetry (CPSV), using multicolor illumination and a color camera. This article describes corrections to remove these bias errors, and their evaluation. Color crosstalk removal is demonstrated with linear unmixing. It is also shown that chromatic aberrations may be removed using either scale calibration, or by processing an image illuminated by all colors simultaneously. CPSV measurements of a fully developed turbulent pipe flow of glycerin were conducted. Corrected velocity statistics from these measurements were compared to both single-color PSV and LDV measurements and showed excellent agreement to fourth-order, to well into the viscous sublayer. Recommendations for practical assessment and correction of color aberration and color crosstalk are discussed. (paper)

  13. Effect of the linkers between the zinc fingers in zinc finger protein 809 on gene silencing and nuclear localization

    Energy Technology Data Exchange (ETDEWEB)

    Ichida, Yu, E-mail: ichida-y@ncchd.go.jp; Utsunomiya, Yuko; Onodera, Masafumi

    2016-03-18

    Zinc finger protein 809 (ZFP809) belongs to the Kruppel-associated box-containing zinc finger protein (KRAB-ZFP) family and functions in repressing the expression of Moloney murine leukemia virus (MoMLV). ZFP809 binds to the primer-binding site (PBS)located downstream of the MoMLV-long terminal repeat (LTR) and induces epigenetic modifications at integration sites, such as repressive histone modifications and de novo DNA methylation. KRAB-ZFPs contain consensus TGEKP linkers between C2H2 zinc fingers. The phosphorylation of threonine residues within linkers leads to the inactivation of zinc finger binding to target sequences. ZFP809 also contains consensus linkers between zinc fingers. However, the function of ZFP809 linkers remains unknown. In the present study, we constructed ZFP809 proteins containing mutated linkers and examined their ability to silence transgene expression driven by MLV, binding ability to MLV PBS, and cellular localization. The results of the present study revealed that the linkers affected the ability of ZFP809 to silence transgene expression. Furthermore, this effect could be partly attributed to changes in the localization of ZFP809 proteins containing mutated linkers. Further characterization of ZFP809 linkers is required for understanding the functions and features of KRAB-ZFP-containing linkers. - Highlights: • ZFP809 has three consensus linkers between the zinc fingers. • Linkers are required for ZFP809 to silence transgene expression driven by MLV-LTR. • Linkers affect the precise nuclear localization of ZFP809.

  14. Low-energy Coulomb excitation of neutron-rich zinc isotopes

    CERN Document Server

    Van de Walle, J; Behrens, T; Bildstein, V; Blazhev, A; Cederkäll, J; Clément, E; Cocolios, T E; Davinson, T; Delahaye, P; Eberth, J; Ekström, A; Fedorov, D V; Fedosseev, V; Fraile, L M; Franchoo, S; Gernhäuser, R; Georgiev, G; Habs, D; Heyde, K; Huber, G; Huyse, M; Ibrahim, F; Ivanov, O; Iwanicki, J; Jolie, J; Kester, O; Köster, U; Kröll, T; Krücken, R; Lauer, M; Lisetskiy, A F; Lutter, R; Marsh, B A; Mayet, P; Niedermaier, O; Pantea, M; Raabe, R; Reiter, P; Sawicka, M; Scheit, H; Schrieder, G; Schwalm, D; Seliverstov, M D; Sieber, T; Sletten, G; Smirnova, N; Stanoiu, M; Stefanescu, I; Thomas, J C; Valiente-Dobón, J J; Van Duppen, P; Verney, D; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Wolf, B H; Zielinska, M

    2009-01-01

    At the radioactive ion beam facility REX-ISOLDE, neutron-rich zinc isotopes were investigated using low-energy Coulomb excitation. These experiments have resulted in B(E2,20) values in 74-80Zn, B(E2,42) values in 74,76Zn and the determination of the energy of the first excited 2 states in 78,80Zn. The zinc isotopes were produced by high-energy proton- (A=74,76,80) and neutron- (A=78) induced fission of 238U, combined with selective laser ionization and mass separation. The isobaric beam was postaccelerated by the REX linear accelerator and Coulomb excitation was induced on a thin secondary target, which was surrounded by the MINIBALL germanium detector array. In this work, it is shown how the selective laser ionization can be used to deal with the considerable isobaric beam contamination and how a reliable normalization of the experiment can be achieved. The results for zinc isotopes and the N=50 isotones are compared to collective model predictions and state-of-the-art large-scale shell-model calculations, i...

  15. Radiation-Induced Grafting for the Synthesis of Adsorbents for Phosphate and Chromate Removal from Aqueous Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kavakli, P A; Kavakli, C; Guven, O [Department of Chemistry, Hacettepe University, Beytepe, 06800, Ankara (Turkey)

    2012-09-15

    Nonwoven fabrics made of PE coated PP fibres were irradiated by accelerated electrons in inert atmospheres for grafting of two different monomers, glycidyl methacrylate and dimethylaminoethyl methacrylate. Grafting conditions were optimized by a systematic investigation of the effects of absorbed dose, monomer concentration, grafting reaction temperature and duration. 150% grafted copolymers were later modified by protonation and quaternization of poly(dimethylaminoethyl methacrylate) chains and by Cu(II) loading of dipyridyl amine modified poly(glycidyl methacrylate) graft chains. The PE/PP based adsorbents thus prepared were used for their suitability of removing phosphate and chromate ions from aqueous systems. Adsorption/removal studies were carried out in both batch and continuous flow type systems. The selectivity of adsorption of phosphate ions in the presence of other competing anions were also checked showing the enhanced selectivity for phosphate ions. (author)

  16. Obtention of zinc polymethacrylate via free radicals induced by gamma radiation; Obtencion del polimetacrilato de zinc via radicales libres inducidos por radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Urena N, F.; Flores E, J. [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, C.P. 52045 Estado de Mexico (Mexico)

    2000-07-01

    The objective of this work was to synthesise the monomer of zinc methacrylate and subsequently to carry out the polymerization reaction with the purpose to obtain the compound desired, the zinc polymethacrylate. For this it was used a gamma radiation source, {sup 60} Co, as initiator of the polymerization reaction. (Author)

  17. Zinc electrode - its behaviour in the nickel oxide-zinc accumulator

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling. 193 references.

  18. Chromatic aberration, accommodation, and color preference in asthenopia.

    Science.gov (United States)

    Drew, Stefanie A; Borsting, Eric; Stark, Lawrence R; Chase, Chris

    2012-07-01

    Asthenopia is a common problem associated with near work and reports suggest that colored lenses or overlays may be applied to reduce symptoms. In this study, we examine the relationship between eyestrain, color preferences, and function of the accommodation and vergence system. Specifically, we examine whether symptomatic observers select colors that reduce accommodative demand based on longitudinal chromatic aberration (LCA). Forty-seven undergraduate students participated in this study. Visual discomfort symptoms were assessed using the Conlon survey. A Mark 2 Intuitive Colorimeter was used to obtain optimal colored light preferences. LCA was modeled using the Chromatic Eye and spectral power density data. A comprehensive evaluation of accommodation and vergence was performed following standard procedures. A significant negative correlation (r = -0.51) was found between eyestrain symptoms and the International Commission on Illumination (CIE) v' axis of colors preferences. Additionally, a significant negative correlation (r = -0.31) was found between eyestrain symptoms and LCA accommodation. Two thirds of the participants in the high discomfort group chose colors that decreased accommodative demand. Accommodative amplitude and vergence facility also correlated with LCA, accounting for 25% of the variance. The color preferences of individuals are systematically influenced by the functioning of their accommodation and vergence systems with increased symptomatology resulting in color selections that reduce LCA accommodative stimulus demand.

  19. The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

    NARCIS (Netherlands)

    Veldkamp, T.; Diepen, van J.T.M.; Bikker, P.

    2014-01-01

    Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR

  20. Contour adaptation reduces the spreading of edge induced colors.

    Science.gov (United States)

    Coia, Andrew J; Crognale, Michael A

    2017-04-25

    Brief exposure to flickering achromatic outlines of an area causes a reduction in the brightness contrast of the surface inside the area. This contour adaptation to achromatic contours does not reduce surface contrast when the surface is chromatic (the saturation or colorimetric purity of the surface is maintained). In addition to reducing the brightness of physical luminance contrast, contour adaptation also reduces (or even reverses) the illusory brightness contrast seen in the Craik-O'Brien-Cornsweet illusion, in which two physically identical grey areas appear different brightness because of a sharp luminance edge separating them. Chromatic color spreading illusions also occur with chromatic inducing edges, and an unanswered question is whether contour adaptation can reduce the perceived contrast of illusory color spreading from edges, even though it cannot reduce the perceived contrast of physical surface color. The current studies use a color spreading illusion known as the watercolor effect in order to test whether illusory color spreading is affected by contour adaptation. The general findings of physical achromatic contrast being reduced and chromatic contrast being robust to contour adaptation were replicated. However, both illusory brightness and color were reduced by contour adaptation, even when the illusion edges only differed in chromatic contrast with each other and the background. Additional studies adapting to chromatic contours showed opposite effects on illusory color contrast than achromatic adaptation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Feed-Forward Corrections for Tune and Chromaticity Injection Decay During 2015 LHC Operation

    CERN Document Server

    Solfaroli Camillocci, Matteo; Lamont, Mike; Schaumann, Michaela; Todesco, Ezio; Wenninger, Jorg

    2016-01-01

    After two years of shutdown, the Large Hadron Collider (LHC) has been operated in 2015 at 6.5 TeV, close to its designed energy. When the current is stable at low field, the harmonic components of the main circuits are subject to a dynamic variation induced by current redistribution on the superconducting cables. The Field Description of the LHC (FiDel) foresaw an increase of the decay at injection of tune (quadrupolar components) and chromaticity (sextupolar components) of about 50% with respect to LHC Run1 due to the higher operational current. This paper discusses the beam-based measurements of the decay during the injection plateau and the implementation and accuracy of the feed-forward corrections as present in 2015. Moreover, the observed tune shift proportional to the circulating beam intensity and it's foreseen feed-forward correction are covered.

  2. Green Synthesized Zinc Oxide (ZnO Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System

    Directory of Open Access Journals (Sweden)

    Kamal K. Panda

    2017-05-01

    Full Text Available Zinc oxide nanoparticles (ZnONP-GS were synthesised from the precursor zinc acetate (Zn(CH3COO2 through the green route using the milky latex from milk weed (Calotropis gigantea L. R. Br by alkaline precipitation. Formation of the ZnONP-GS was monitored by UV-visible spectroscopy followed by characterization and confirmation by energy-dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, and X-ray diffraction (XRD. Both the ZnONP-GS and the commercially available ZnONP-S (Sigma-Aldrich and cationic Zn2+ from Zn(CH3COO2 were tested in a dose range of 0–100 mg·L−1 for their potency (i to induce oxidative stress as measured by the generation reactive oxygen species (ROS: O2•−, H2O2 and •OH, cell death, and lipid peroxidation; (ii to modulate the activities of antioxidant enzymes: catalase (CAT, superoxide dismutase (SOD, guaiacol peroxidase (GPX, and ascorbate peroxidase (APX; and (iii to cause DNA damage as determined by Comet assay in Lathyrus sativus L. root bioassay system. Antioxidants such as Tiron and dimethylthiourea significantly attenuated the ZnONP-induced oxidative and DNA damage, suggesting the involvement of ROS therein. Our study demonstrated that both ZnONP-GS and ZnONP-S induced oxidative stress and DNA damage to a similar extent but were significantly less potent than Zn2+ alone.

  3. Spatial profile of contours inducing long-range color assimilation.

    Science.gov (United States)

    Devinck, Frédéric; Spillmann, Lothar; Werner, John S

    2006-01-01

    Color induction was measured using a matching method for two spatial patterns, each composed of double contours. In one pattern (the standard), the contours had sharp edges to induce the Watercolor Effect (WCE); in the other, the two contours had a spatial taper so that the overall profile produced a sawtooth edge, or ramped stimulus. These patterns were chosen based on our previous study demonstrating that the strength of the chromatic WCE depends on a luminance difference between the two contours. Low-pass chromatic mechanisms, unlike bandpass luminance mechanisms, may be expected to be insensitive to the difference between the two spatial profiles. The strength of the watercolor spreading was similar for the two patterns at narrow widths of the contour possibly because of chromatic aberration, but with wider contours, the standard stimulus produced stronger assimilation than the ramped stimulus. This research suggests that luminance-dependent chromatic mechanisms mediate the WCE and that these mechanisms are sensitive to differences in the two spatial profiles of the pattern contours only when they are wide.

  4. On the size of edge chromatic 5-critical graphs

    Directory of Open Access Journals (Sweden)

    K. Kayathri

    2017-04-01

    Full Text Available In this paper, we study the size of edge chromatic 5-critical graphs in several classes of 5-critical graphs. In most of the classes of 5-critical graphs in this paper, we have obtained their exact size and in the other classes of 5-critical graphs, we give new bounds on their number of major vertices and size.

  5. Ultrasonic assisted rapid synthesis of high uniform super-paramagnetic microspheres with core-shell structure and robust magneto-chromatic ability

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenyan, E-mail: wiseyanyan@jit.edu.cn [College of Material Engineering, Jinling Institute of technology, Nanjing (China); Chen, Jiahua [College of Material Engineering, Jinling Institute of technology, Nanjing (China); Wang, Wei [Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing (China); School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing (China); Lu, GongXuan [State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Hao, Lingyun [College of Material Engineering, Jinling Institute of technology, Nanjing (China); Ni, Yaru; Lu, Chunhua; Xu, Zhongzi [Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing (China); State Key Laboratory of Materials-Oriented Chemical Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing (China)

    2017-03-15

    Super-paramagnetic core-shell microspheres were synthesized by ultrasonic assisted routine under low ultrasonic irradiation powers. Compared with conventional routine, ultrasonic effect could not only improve the uniformity of the core-shell structure of Fe{sub 3}O{sub 4}@SiO{sub 2}, but shorten the synthesis time in large scale. Owing to their hydrophilicity and high surface charge, the Fe{sub 3}O{sub 4}@SiO{sub 2} microspheres could be dispersed well in distilled water to form homogeneous colloidal suspension. The suspensions have favorable magneto-chromatic ability that they sensitively exhibit brilliant colorful ribbons by magnetic attraction. The colorful ribbons, which distributed along the magnetic lines, make morphology of the magnetic fields become “visible” to naked eyed. Those colorful ribbons originate from strong magnetic interaction between the microspheres and magnetic fields. Furthermore, the magneto-chromatic performance is reversible as the colorful ribbons vanished rapidly with the removing of magnetic fields. The silica layer effectively enhanced the acid resistance and surface-oxidation resistance of theFe{sub 3}O{sub 4}@SiO{sub 2} microspheres, so they could exhibit stable magnetic nature and robust magneto-chromatic property in acid environment. - Graphical abstract: The Graphical abstract shows the sensitive magneto-chromatic ability, the acid resistance ability as well as the magneto-chromatic mechanism of the Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}@SiO{sub 2} suspension. - Highlights: • Sensitive and reversible robust magneto-chromatic property under magnetic attraction. • Morphology of magnetic field “visible” to naked eyes. • Enhance acid resistance and surface-oxidation resistance. • Ultrasonic effect largely shorten the synthesis time of high uniform microspheres.

  6. Ultrasonic assisted rapid synthesis of high uniform super-paramagnetic microspheres with core-shell structure and robust magneto-chromatic ability

    International Nuclear Information System (INIS)

    Zhang, Wenyan; Chen, Jiahua; Wang, Wei; Lu, GongXuan; Hao, Lingyun; Ni, Yaru; Lu, Chunhua; Xu, Zhongzi

    2017-01-01

    Super-paramagnetic core-shell microspheres were synthesized by ultrasonic assisted routine under low ultrasonic irradiation powers. Compared with conventional routine, ultrasonic effect could not only improve the uniformity of the core-shell structure of Fe_3O_4@SiO_2, but shorten the synthesis time in large scale. Owing to their hydrophilicity and high surface charge, the Fe_3O_4@SiO_2 microspheres could be dispersed well in distilled water to form homogeneous colloidal suspension. The suspensions have favorable magneto-chromatic ability that they sensitively exhibit brilliant colorful ribbons by magnetic attraction. The colorful ribbons, which distributed along the magnetic lines, make morphology of the magnetic fields become “visible” to naked eyed. Those colorful ribbons originate from strong magnetic interaction between the microspheres and magnetic fields. Furthermore, the magneto-chromatic performance is reversible as the colorful ribbons vanished rapidly with the removing of magnetic fields. The silica layer effectively enhanced the acid resistance and surface-oxidation resistance of theFe_3O_4@SiO_2 microspheres, so they could exhibit stable magnetic nature and robust magneto-chromatic property in acid environment. - Graphical abstract: The Graphical abstract shows the sensitive magneto-chromatic ability, the acid resistance ability as well as the magneto-chromatic mechanism of the Fe_3O_4 and Fe_3O_4@SiO_2 suspension. - Highlights: • Sensitive and reversible robust magneto-chromatic property under magnetic attraction. • Morphology of magnetic field “visible” to naked eyes. • Enhance acid resistance and surface-oxidation resistance. • Ultrasonic effect largely shorten the synthesis time of high uniform microspheres.

  7. A moonlighting function of Mycobacterium smegmatis Ku in zinc homeostasis?

    Science.gov (United States)

    Kushwaha, Ambuj K; Deochand, Dinesh K; Grove, Anne

    2015-02-01

    Ku protein participates in DNA double-strand break repair via the nonhomologous end-joining pathway. The three-dimensional structure of eukaryotic Ku reveals a central core consisting of a β-barrel domain and pillar and bridge regions that combine to form a ring-like structure that encircles DNA. Homologs of Ku are encoded by a subset of bacterial species, and they are predicted to conserve this core domain. In addition, the bridge region of Ku from some bacteria is predicted from homology modeling and sequence analyses to contain a conventional HxxC and CxxC (where x is any residue) zinc-binding motif. These potential zinc-binding sites have either deteriorated or been entirely lost in Ku from other organisms. Using an in vitro metal binding assay, we show that Mycobacterium smegmatis Ku binds two zinc ions. Zinc binding modestly stabilizes the Ku protein (by ∼3°C) and prevents cysteine oxidation, but it has little effect on DNA binding. In vivo, zinc induces significant upregulation of the gene encoding Ku (∼sixfold) as well as a divergently oriented gene encoding a predicted zinc-dependent MarR family transcription factor. Notably, overexpression of Ku confers zinc tolerance on Escherichia coli. We speculate that zinc-binding sites in Ku proteins from M. smegmatis and other mycobacterial species have been evolutionarily retained to provide protection against zinc toxicity without compromising the function of Ku in DNA double-strand break repair. © 2014 The Protein Society.

  8. Post-column reaction for simultaneous analysis of chromatic and leuco forms of malachite green and crystal violet by high-performance liquid chromatography with photometric detection

    Science.gov (United States)

    Allen, J.L.; Meinertz, J.R.

    1991-01-01

    The chromatic and leuco forms of malachite green and crystal violet were readily separated and detected by a sensitive and selective high-performance liquid chromatographic procedure. The chromatic and leuco forms of the dyes were separated within 11 min on a C18 column with a mobile phase of 0.05 M sodium acetate and 0.05 M acetic acid in water (19%) and methanol (81%). A reaction chamber, containing 10% PbO2 in Celite 545, was placed between the column and the spectrophotometric detector to oxidize the leuco forms of the dyes to their chromatic forms. Chromatic and leuco malachite green were quantified by their absorbance at 618 nm; and chromatic and leuco Crystal Violet by their absorbance at 588 nm. Detection limits for chromatic and leuco forms of both dyes ranged from 0.12 to 0.28 ng. A linear range of 1 to 100 ng was established for both forms of the dyes.

  9. Thioredoxin-albumin fusion protein prevents copper enhanced zinc-induced neurotoxicity via its antioxidative activity.

    Science.gov (United States)

    Tanaka, Ken-Ichiro; Shimoda, Mikako; Chuang, Victor T G; Nishida, Kento; Kawahara, Masahiro; Ishida, Tatsuhiro; Otagiri, Masaki; Maruyama, Toru; Ishima, Yu

    2018-01-15

    Zinc (Zn) is a co-factor for a vast number of enzymes, and functions as a regulator for immune mechanism and protein synthesis. However, excessive Zn release induced in pathological situations such as stroke or transient global ischemia is toxic. Previously, we demonstrated that the interaction of Zn and copper (Cu) is involved in the pathogenesis of Alzheimer's disease and vascular dementia. Furthermore, oxidative stress has been shown to play a significant role in the pathogenesis of various metal ions induced neuronal death. Thioredoxin-Albumin fusion (HSA-Trx) is a derivative of thioredoxin (Trx), an antioxidative protein, with improved plasma retention and stability of Trx. In this study, we examined the effect of HSA-Trx on Cu 2+ /Zn 2+ -induced neurotoxicity. Firstly, HSA-Trx was found to clearly suppress Cu 2+ /Zn 2+ -induced neuronal cell death in mouse hypothalamic neuronal cells (GT1-7 cells). Moreover, HSA-Trx markedly suppressed Cu 2+ /Zn 2+ -induced ROS production and the expression of oxidative stress related genes, such as heme oxygenase-1. In contrast, HSA-Trx did not affect the intracellular levels of both Cu 2+ and Zn 2+ after Cu 2+ /Zn 2+ treatment. Finally, HSA-Trx was found to significantly suppress endoplasmic reticulum (ER) stress response induced by Cu 2+ /Zn 2+ treatment in a dose dependent manner. These results suggest that HSA-Trx counteracted Cu 2+ /Zn 2+ -induced neurotoxicity by suppressing the production of ROS via interfering the related gene expressions, in addition to the highly possible radical scavenging activity of the fusion protein. Based on these findings, HSA-Trx has great potential as a promising therapeutic agent for the treatment of refractory neurological diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Theoretical studies of the pressure-induced zinc-blende to cinnabar phase transition in CdTe and thermodynamical properties of each phase

    International Nuclear Information System (INIS)

    Brik, M.G.; Łach, P.; Karczewski, G.; Wojtowicz, T.; Kamińska, A.; Suchocki, A.

    2013-01-01

    Luminescence of CdTe quantum dots embedded in ZnTe is quenched at pressure of about 4.5 GPa in the high-pressure experiments. This pressure-induced quenching is attributed to the “zinc-blende–cinnabar” phase transition in CdTe, which was confirmed by the first-principles calculations. Theoretical analysis of the pressure at which the phase transition occurs for CdTe was performed using the CASTEP module of Materials Studio package with both generalized gradient approximation (GGA) and local density approximation (LDA). The calculated phase transition pressures are equal to about 4.4 GPa and 2.6 GPa, according to the GGA and LDA calculations, respectively, which is in a good agreement with the experimental value. Theoretically estimated value of the pressure coefficient of the band-gap luminescence in zinc-blende structure is in very good agreement with that recently measured in the QDs structures. The calculated Debye temperature, elastic constants and specific heat capacity for the zinc-blend structure agree well with the experimental data; the data for the cinnabar phase are reported here for the first time to the best of the authors' knowledge. - Highlights: • Quenching of luminescence of CdTe quantum dots embedded in ZnTe is theoretically explained. • The theoretical calculation of elastic and thermodynamic properties of CdTe by two types of ab-initio methods. • Theoretical calculations of some optical properties of CdTe under pressure in zinc-blende and cinnabar phases

  11. Early-in-life dietary zinc deficiency and supplementation and mammary tumor development in adulthood female rats.

    Science.gov (United States)

    da Silva, Flávia R M; Grassi, Tony F; Zapaterini, Joyce R; Bidinotto, Lucas T; Barbisan, Luis F

    2017-06-01

    Zinc deficiency during pregnancy and postnatal life can adversely increase risk of developing human diseases at adulthood. The present study was designed to evaluate whether dietary zinc deficiency or supplementation during the pregnancy, lactation and juvenile stages interferes in the development of mammary tumors induced by 7,12-dimethylbenzanthracene (DMBA) in female Sprague-Dawley (SD) rats. Pregnant female SD rats were allocated into three groups: zinc-adequate diet (ZnA - 35-mg/kg chow), zinc-deficient diet (ZnD - 3-mg/kg chow) or zinc-supplemented diet (ZnS - 180-mg/kg chow) during gestational day 10 (GD 10) until the litters' weaning. Female offspring received the same diets as their dams until postnatal day (PND) 51. At PND 51, the animals received a single dose of DMBA (50 mg/kg, ig) and zinc-adequate diets. At PND 180, female were euthanized, and tumor samples were processed for histological evaluation and gene expression microarray analysis. The ZnD induced a significant reduction in female offspring body weight evolution and in mammary gland development. At late in life, the ZnD or ZnS did not alter the latency, incidence, multiplicity, volume or histological types of mammary tumors in relation to the ZnA group. However, the total tumor number in ZnS group was higher than in ZnA group, accompanied by distinct expression of 4 genes up- and 15 genes down-regulated. The present findings indicate that early-in-life dietary zinc supplementation, differently to zinc deficiency, has a potential to modify the susceptibility to the development of mammary tumors induced by DMBA. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Effect of consuming zinc-fortified bread on serum zinc and iron status of zinc-deficient women: A double blind, randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Akbar Badii

    2012-01-01

    Full Text Available After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1 a non-fortified bread, (2 a high-zinc bread, and (3 a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05. Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p < 0.01. It was concluded that fortification of flour with 50-100 ppm zinc was an effective way to achieve adequate zinc intake and absorption in zinc-deficient people. It also appeared that consuming zinc-fortified bread improved iron absorption.

  13. Potential Remobilization of Toxic Anions during Reduction of Arsenated and Chromated Schwertmannite by the Dissimilatory Fe(III)-Reducing Bacterium Acidiphilium cryptum JF-5

    International Nuclear Information System (INIS)

    Regenspurg, Simona; Goessner, Anita; Peiffer, Stefan; Kuesel, Kirsten

    2002-01-01

    Schwertmannite, an iron(III)-oxyhydroxysulfate formed in acidic mining-impacted stream or lake waters often contaminated with toxic elements like arsenate or chromate, is able to incorporate high amounts of these oxyanions. Detoxification of the water might be achieved if precipitated arsenated or chromated schwertmannite is fixed in the sediment. However, under reduced conditions, reductive dissolution of iron oxides mediated by the activity of Fe(III)-reducing bacteria might mobilize arsenate and chromate again. In this study, the reduction of synthesized arsenated or chromated schwertmannite by the acidophilic Fe(III)-reducer Acidiphilium cryptum JF-5, isolated from an acidic mining-impacted sediment, was investigated. In TSB medium at pH 2.7 with glucose as electron donor, A. cryptum JF-5 reduced about 10% of the total Fe(III) present in pure synthetic schwertmannite but only 5% of Fe(III) present in arsenated schwertmannite. In contrast to sulfate that was released during the reductive dissolution of pure schwertmannite, arsenate was not released during the reduction of arsenated schwertmannite probably due to the high surface complexation constant of arsenate and Fe(III). In medium containing chromated schwertmannite, no Fe(II) was formed, and no glucose was consumed indicating that chromate might have been toxic to cells of A. cryptum JF-5. Both As(V) or Cr(VI) could not be utilized as electron acceptor by A. cryptum JF-5. A comparison between autoclaved (121 o C for 20 min) and non-autoclaved schwertmannite samples demonstrated that nearly 100%of the bound sulfate was released during heating, and FTIR spectra indicated a transformation of schwertmannite to goethite. This structural change was not observed with autoclaved arsenated or chromated schwertmannite. These results suggest that the mobility of arsenate and chromate is not enhanced by the activity of acidophilic Fe(III)-reducing bacteria in mining-impacted sediments. In contrast, the presence of

  14. Chromatic Image Analysis For Quantitative Thermal Mapping

    Science.gov (United States)

    Buck, Gregory M.

    1995-01-01

    Chromatic image analysis system (CIAS) developed for use in noncontact measurements of temperatures on aerothermodynamic models in hypersonic wind tunnels. Based on concept of temperature coupled to shift in color spectrum for optical measurement. Video camera images fluorescence emitted by phosphor-coated model at two wavelengths. Temperature map of model then computed from relative brightnesses in video images of model at those wavelengths. Eliminates need for intrusive, time-consuming, contact temperature measurements by gauges, making it possible to map temperatures on complex surfaces in timely manner and at reduced cost.

  15. Co-induction of p75NTR and p75NTR-associated death executor in neurons after zinc exposure in cortical culture or transient ischemia in the rat.

    Science.gov (United States)

    Park, J A; Lee, J Y; Sato, T A; Koh, J Y

    2000-12-15

    Recently, a 22 kDa protein termed p75(NTR)-associated death executor (NADE) was discovered to be a necessary factor for p75(NTR)-mediated apoptosis in certain cells. However, the possible role for p75(NTR)/NADE in pathological neuronal death has yet been undetermined. In the present study, we have examined this possibility in vivo and in vitro. Exposure of cortical cultures to zinc induced both p75(NTR) and NADE in neurons, whereas exposure to NMDA, ionomycin, iron, or H(2)O(2) induced neither. In addition, zinc exposure increased neuronal NGF expression and its release into the medium. A function-blocking antibody of p75(NTR) (REX) inhibited association between p75(NTR) and NADE as well as neuronal death induced by zinc. Conversely, NGF augmented zinc-induced neuronal death. Caspase inhibitors reduced zinc-induced neuronal death, indicating that caspases were involved. Because reduction of NADE expression with cycloheximide or NADE antisense oligonucleotides attenuated zinc-induced neuronal death, NADE appears to contribute to p75(NTR)-induced cortical neuronal death as shown in other cells. Because zinc neurotoxicity may be a key mechanism of neuronal death after transient forebrain ischemia, we next examined this model. After ischemia, p75(NTR) and NADE were induced in degenerating rat hippocampal CA1 neurons. There was a close correlation between zinc accumulation and p75(NTR)/NADE induction. Suggesting the role of zinc here, injection of a metal chelator, CaEDTA, into the lateral ventricle completely blocked the induction of p75(NTR) and NADE. Our results suggest that co-induction of p75(NTR) and NADE plays a role in zinc-triggered neuronal death in vitro and in vivo.

  16. Chromatic correction for a VIS-SWIR zoom lens using optical glasses

    Science.gov (United States)

    Zhao, Yang; Williams, Daniel J. L.; McCarthy, Peter; Visconti, Anthony J.; Bentley, Julie L.; Moore, Duncan T.

    2015-09-01

    With the advancement in sensors, hyperspectral imaging in short wave infrared (SWIR 0.9 μm to 1.7 μm) now has wide applications, including night vision, haze-penetrating imaging, etc. Most conventional optical glasses can be material candidates for designing in the SWIR as they transmit up to 2.2 μm. However, since SWIR is in the middle of the glasses' major absorption wavebands in UV and IR, the flint glasses in SWIR are less dispersive than in the visible spectrum. As a result, the glass map in the SWIR is highly compressed, with crowns and flints all clustering together. Thus correcting for chromatic aberration is more challenging in the SWIR, since the Abbé number ratio of the same glass combination is reduced. Conventionally, fluorides, such as CaF2 and BaF2, are widely used in designing SWIR system due to their unique dispersion properties, even though they are notorious for poor manufacturability or even high toxicity. For lens elements in a zoom system, the ray bundle samples different sections of the each lens aperture as the lens zooms. This creates extra uncertainty in correcting chromatic aberrations. This paper focuses on using only commercially available optical glasses to color-correct a 3X dual-band zoom lens system in the VIS-SWIR. The design tools and techniques are detailed in terms of material selections to minimize the chromatic aberrations in such a large spectrum band and all zoom positions. Examples are discussed for designs with different aperture stop locations, which considerably affect the material choices.

  17. Thin-Sheet zinc-coated and carbon steels laser welding

    International Nuclear Information System (INIS)

    Pecas, P.; Gouveia, H.; Quintino, L.

    1998-01-01

    This paper describes the results of a research on CO 2 laser welding of thin-sheet carbon steels (Zinc-coated and uncoated), at several thicknesses combinations. Laser welding has an high potential to be applied on sub-assemblies welding before forming to the automotive industry-tailored blanks. The welding process is studied through the analysis of parameters optimization, metallurgical quality and induced distortions by the welding process. The clamping system and the gas protection system developed are fully described. These systems allow the minimization of common thin-sheet laser welding defects like misalignment, and zinc-coated laser welding defects like porous and zinc ventilation. The laser welding quality is accessed by DIN 8563 standard, and by tensile, microhardness and corrosion test. (Author) 8 refs

  18. Candida albicans induces Metabolic Reprogramming in human NK cells and responds to Perforin with a Zinc Depletion Response

    Directory of Open Access Journals (Sweden)

    Daniela eHellwig

    2016-05-01

    Full Text Available As part of the innate immune system, natural killer (NK cells are directly involved in the response to fungal infections. Perforin has been identified as the major effector molecule acting against many fungal pathogens. While several studies have shown that perforin mediated fungicidal effects can contribute to fungal clearance, neither the activation of NK cells by fungal pathogens nor the effects of perforin on fungal cells are well understood. In a dual approach, we have studied the global gene expression pattern of primary and cytokine activated NK cells after co-incubation with C. albicans and the transcriptomic adaptation of C. albicans to perforin exposure. NK cells responded to the fungal pathogen with an up-regulation of genes involved in immune signaling and release of cytokines. Furthermore, we observed a pronounced increase of genes involved in glycolysis and glycolysis inhibitor 2-deoxy-D-glucose impaired C. albicans induced NK cell activation. This strongly indicates that metabolic adaptation is a major part of the NK cell response to C. albicans infections. In the fungal pathogen, perforin induced a strong up-regulation of several fungal genes involved in the zinc depletion response, such as PRA1 and ZRT1. These data suggest that fungal zinc homeostasis is linked to the reaction to perforin secreted by NK cells. However, deletion mutants in PRA1 and ZRT1 did not show altered susceptibility to perforin.

  19. Production of zinc pellets

    Science.gov (United States)

    Cooper, J.F.

    1996-11-26

    Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries. 6 figs.

  20. Implementing New Non-Chromate Coatings Systems (Briefing Charts)

    Science.gov (United States)

    2011-02-09

    Initiate Cr6+ authorization process for continued Cr6+ use using the form, Authorization to Use Hexavalent Chromium. YES NO • Approval of...Aluminum and magnesium anodizing • Hard Chrome Plating • Type II conversion coating on aluminum alloys under chromated primer • Type II conversion coating...Elimination of Hexavalent Chromium 80% 5% 14% 1% Type II Type III Type IC Type IC Fatigue Critical 50% 50% Type II Type IC FRC-SE (JAX) Fully Integrated FRC