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Sample records for aberrant testa shape

  1. Transition from two to one integument in Prunus species: expression pattern of INNER NO OUTER (INO), ABERRANT TESTA SHAPE (ATS) and ETTIN (ETT).

    PubMed

    Lora, Jorge; Hormaza, José I; Herrero, Maria

    2015-10-01

    While gymnosperm ovules have one integument, in most angiosperms two integuments surround the ovules. Unitegmic ovules have arisen independently several times during the evolution of angiosperms, but the ultimate genetic cause of the presence of a single integument remains elusive. We compared species of the genus Prunus that have different numbers of integuments: bitegmic species, such as Prunus armeniaca (apricot) and Prunus persica (peach), and unitegmic species, such as Prunus incisa, analyzing the expression pattern of genes that are involved in integument development in Arabidopsis thaliana: INNER NO OUTER (INO), ABERRANT TESTA SHAPE (ATS) and ETTIN (ETT). Bitegmic and unitegmic species showed similar INO expression patterns, indicative of the conservation of an outer integument. However, expression of ETT, which occurs in the boundary of the outer and inner integuments, was altered in unitegmic ovules, which showed lack of ETT expression. These results strongly suggest that the presence of a single integument could be attributable to the amalgamation of two integuments and support the role of ETT in the fusion of the outer and inner integuments in unitegmic ovules, a situation that could be widespread in other unitegmic species of angiosperms.

  2. The Sensitivity of Shaped Pupil Coronagraphs to Optical Aberrations

    NASA Technical Reports Server (NTRS)

    Green, Joseph J.; Shaklan, Stuart B.; Vanderbei, Robert J.; Kasdin, N. Jeremy

    2004-01-01

    Unlike focal-plane coronagraphs that use occulting spots and Lyot stops to eliminate diffraction, pupil-plane coronagraphs operate by shaping the pupil to redirect the diffracted stellar light into a tight core. As in focal-plane coronagraphs, the optical aberrations in the telescope must be sufficiently corrected to enable high contrast imaging. However, in shaped-pupil coronagraphs, the low-order aberrations resulting from misalignment and optical figure drift have a much smaller influence upon the contrast at at the inner working angle. These weaker sensitivities greatly relax the strict low-order wavefront stability required for high-contrast imaging the cost of some throughput. In this paper, we present the simulated performance of the concentric ring shaped pupil concepts comparing them to focal-plane coronagraphs that are optimized for the same inner working angles.

  3. Influence of the Testa on Seed Dormancy, Germination, and Longevity in Arabidopsis1

    PubMed Central

    Debeaujon, Isabelle; Léon-Kloosterziel, Karen M.; Koornneef, Maarten

    2000-01-01

    The testa of higher plant seeds protects the embryo against adverse environmental conditions. Its role is assumed mainly by controlling germination through dormancy imposition and by limiting the detrimental activity of physical and biological agents during seed storage. To analyze the function of the testa in the model plant Arabidopsis, we compared mutants affected in testa pigmentation and/or structure for dormancy, germination, and storability. The seeds of most mutants exhibited reduced dormancy. Moreover, unlike wild-type testas, mutant testas were permeable to tetrazolium salts. These altered dormancy and tetrazolium uptake properties were related to defects in the pigmentation of the endothelium and its neighboring crushed parenchymatic layers, as determined by vanillin staining and microscopic observations. Structural aberrations such as missing layers or a modified epidermal layer in specific mutants also affected dormancy levels and permeability to tetrazolium. Both structural and pigmentation mutants deteriorated faster than the wild types during natural aging at room temperature, with structural mutants being the most strongly affected. PMID:10677433

  4. Interferometric control of contact line, shape, and aberrations of liquid lenses

    NASA Astrophysics Data System (ADS)

    Voitenko, Igor; Storm, Ronald; Westfall, Raymond; Rogers, Stanley

    2007-09-01

    An optical system consisting of an aqueous electrolyte resting on a polymer/gold/indium-tin-oxide (ITO) layer deposited onto a glass substrate is analyzed to acquire contact angle - focal distance data as a function of applied voltage. The shape factor of a liquid lens and its dependence on the perimeter of contact line and contact angle was analyzed in the presence of an electrical field applied between the electrolyte and planar electrode system. The contact angle of a liquid on a thin, transparent film of gold (20 nm thick) - on ITO under electrolyte solution could be varied from 110 +/- 3° when the gold was held at -2.4 V to 41 +/- 3° without voltage. The behavior of a water-based electrolyte and water-soluble polymer blend and its influence on the shape of contact line and profile of the lens were investigated by employing a holographic setup at wavelengths of 632.8 and 543.5 nm. Optical micrographs showing the profile of the lens, aberration-less aperture, deformation of contact line, and shape of the liquid lens, respectively, were analyzed in reflection and transmission. Both the advancing and receding contact angles were measured directly from digitized images of the profile of the lens. The dynamic range of linear beam steering and dependence of the focal length of the liquid lens on the applied voltage are discussed.

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

    PubMed

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

    2015-10-20

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

  6. An analytical approach to estimating aberrations in curved multilayer optics for hard x-rays: 1. Derivation of caustic shapes.

    PubMed

    Guigay, J-P; Morawe, Ch; Mocella, V; Ferrero, C

    2008-08-04

    An analytical approach has been developed to derive aberration effects in parabolic and elliptic multilayer optics with weak interaction between photons and matter. The method is based on geometrical ray tracing including refraction effects up to the first order of the refractive index decrement delta. In the parabolic case, the derivation leads to simple parametric equations for the caustic shape. In the elliptic case, the analytical results more involved, but can be well approximated by the parabolic solution. Both geometries are compared with regard to the fundamental impact on their focusing properties.

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

    PubMed

    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.

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

    PubMed Central

    Stubbs, Alexander L.; Stubbs, Christopher W.

    2016-01-01

    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. PMID:27382180

  9. Identification of an antioxidant, ethyl protocatechuate, in peanut seed testa.

    PubMed

    Huang, Shiow Chyn; Yen, Gow-Chin; Chang, Lee-Wen; Yen, Wen-Jye; Duh, Pin-Der

    2003-04-09

    The antioxidant activity and identification of the antioxidant component of peanut seed testa were investigated. The antioxidant activity of peanut seed testa was studied in the linoleic acid model system by using the ferric thiocyanate method. Among the five organic solvent extracts, the ethanolic extracts of peanut seed testa (EEPST) produced higher yields and stronger antioxidant activity than other organic solvent extracts. EEPST was separated into 17 fractions on silica gel column chromatography. Fraction 17, which showed the largest yield and significant antioxidant activity, was separated by thin-layer chromatography. Four major antioxidative subfractions were present. Subfraction 17-2 was found to be effective in preventing oxidation of linoleic acid. This subfraction was further fractionated and isolated and characterized by UV, MS, IR, and (1)H NMR techniques. The active compound was identified as ethyl protocatechuate (3,4-dihydroxybenzoic acid ethyl ester).

  10. Reductive-degradation of carcinogenic azo dyes using Anacardium occidentale testa derived silver nanoparticles.

    PubMed

    Edison, Thomas Nesakumar Jebakumar Immanuel; Atchudan, Raji; Sethuraman, Mathur Gopalakrishnan; Lee, Yong Rok

    2016-09-01

    In the present work, reductive-degradation of azo dyes such as congo red (CR) and methyl orange (MO) was manifested using Anacardium occidentale testa derived silver nanoparticles (AgNPs) as a catalyst. The formation of highly stable AgNPs were visually confirmed by the appearance of yellow color and further substantiated by the existence of surface plasmon resonance (SPR) peak around 425nm. The effect of A. occidentale concentration, reaction time and pH in the formations of AgNPs was corroborated by UV-visible (UV-Vis) spectroscopy. The Fourier transform infrared (FT-IR) spectroscopic results proved that phytoconstituents of A. occidentale testa acts as a capping agent and thereby protects the AgNPs from aggregation. The crystalline nature of the AgNPs was validated from the XRD patterns. The average size of synthesized AgNPs was 25nm, with distorted spherical shape was ascribed from the high resolution transmission electron microscopic (HR-TEM) images. Due to the high stability of the as-synthesized AgNPs, they were utilized for the degradation of carcinogenic azo dyes such as CR and MO using NaBH4 and its catalytic activity was studied via UV-Vis spectroscopy. The results proved that extraordinary catalytic activity of synthesized AgNPs towards the reductive-degradation of both CR and MO.

  11. Flavonoid accumulation patterns of transparent testa mutants of arabidopsis

    NASA Technical Reports Server (NTRS)

    Peer, W. A.; Brown, D. E.; Tague, B. W.; Muday, G. K.; Taiz, L.; Murphy, A. S.

    2001-01-01

    Flavonoids have been implicated in the regulation of auxin movements in Arabidopsis. To understand when and where flavonoids may be acting to control auxin movement, the flavonoid accumulation pattern was examined in young seedlings and mature tissues of wild-type Arabidopsis. Using a variety of biochemical and visualization techniques, flavonoid accumulation in mature plants was localized in cauline leaves, pollen, stigmata, and floral primordia, and in the stems of young, actively growing inflorescences. In young Landsberg erecta seedlings, aglycone flavonols accumulated developmentally in three regions, the cotyledonary node, the hypocotyl-root transition zone, and the root tip. Aglycone flavonols accumulated at the hypocotyl-root transition zone in a developmental and tissue-specific manner with kaempferol in the epidermis and quercetin in the cortex. Quercetin localized subcellularly in the nuclear region, plasma membrane, and endomembrane system, whereas kaempferol localized in the nuclear region and plasma membrane. The flavonoid accumulation pattern was also examined in transparent testa mutants blocked at different steps in the flavonoid biosynthesis pathway. The transparent testa mutants were shown to have precursor accumulation patterns similar to those of end product flavonoids in wild-type Landsberg erecta, suggesting that synthesis and end product accumulation occur in the same cells.

  12. Architectural phenotypes in the transparent testa mutants of Arabidopsis thaliana

    PubMed Central

    Buer, Charles S.; Djordjevic, Michael A.

    2009-01-01

    Flavonoids are low molecular weight secondary plant metabolites with a myriad of functions. As flavonoids affect auxin transport (an important growth-controlling hormone) and are biologically active in eukaryotes, flavonoid mutants were expected to have undescribed architectural phenotypes. The Arabidopsis thaliana transparent testa (tt) mutants are compromised in the enzymatic steps or transcriptional regulators affecting flavonoid synthesis. tt mutant seedlings were grown on hard-slanted agar (a stress condition), under varying light conditions, and in soil to examine the resulting growth patterns. These tt mutants revealed a wide variety of architectural phenotypes in root and aerial tissues. Mutants with increased inflorescences, siliques, and lateral root density or reduced stature are traits that could affect plant yield or performance under certain environmental conditions. The regulatory genes affected in architectural traits may provide useful molecular targets for examination in other plants. PMID:19129166

  13. The Allium Test--A Simple, Eukaryote Genotoxicity Assay.

    ERIC Educational Resources Information Center

    Babich, H.; Segall, M. A.; Fox, K. D.

    1997-01-01

    Explains the allium test in which roots are excised from onion bulblets grown in aqueous solutions of a test agent. Root tips are then isolated and stained with aceto-orcein, and chromosomal aberrations are microscopically observed. (Author/AIM)

  14. Examining the Effects of Chromatic Aberration, Object Distance, and Eye Shape on Image-Formation in the Mirror-Based Eyes of the Bay Scallop Argopecten irradians.

    PubMed

    Speiser, Daniel I; Gagnon, Yakir Luc; Chhetri, Raghav K; Oldenburg, Amy L; Johnsen, Sönke

    2016-11-01

    The eyes of scallops form images using a concave spherical mirror and contain two separate retinas, one layered on top of the other. Behavioral and electrophysiological studies indicate that the images formed by these eyes have angular resolutions of about 2°. Based on previous ray-tracing models, it has been thought that the more distal of the two retinas lies near the focal point of the mirror and that the proximal retina, positioned closer to the mirror at the back of the eye, receives light that is out-of-focus. Here, we propose three mechanisms through which both retinas may receive focused light: (1) chromatic aberration produced by the lens may cause the focal points for longer and shorter wavelengths to fall near the distal and proximal retinas, respectively; (2) focused light from near and far objects may fall on the distal and proximal retinas, respectively; and (3) the eyes of scallops may be dynamic structures that change shape to determine which retina receives focused light. To test our hypotheses, we used optical coherence tomography (OCT), a method of near-infrared optical depth-ranging, to acquire virtual cross-sections of live, intact eyes from the bay scallop Argopecten irradians Next, we used a custom-built ray-tracing model to estimate the qualities of the images that fall on an eye's distal and proximal retinas as functions of the wavelengths of light entering the eye (400-700 nm), object distances (0.01-1 m), and the overall shape of the eye. When we assume 550 nm wavelength light and object distances greater than 0.01 m, our model predicts that the angular resolutions of the distal and proximal retinas are 2° and 7°, respectively. Our model also predicts that neither chromatic aberration nor differences in object distance lead to focused light falling on the distal and proximal retinas simultaneously. However, if scallops can manipulate the shapes of their eyes, perhaps through muscle contractions, we speculate that they may be able

  15. Aberration correction of unstable resonators

    NASA Technical Reports Server (NTRS)

    Lang, Robert J. (Inventor)

    1994-01-01

    Construction of aspheric reflectors for unstable resonator lasers to provide an arbitrary laser mode inside the resonator to correct aberrations of an output beam by the construction of the shape of an end reflector opposite the output reflector of the resonator cavity, such as aberrations resulting from refraction of a beam exiting the solid of the resonator having an index of refraction greater than 1 or to produce an aberration in the output beam that will precisely compensate for the aberration of an optical train into which the resonator beam is coupled.

  16. Effect of roasting on phenolic content and antioxidant activities of whole cashew nuts, kernels, and testa.

    PubMed

    Chandrasekara, Neel; Shahidi, Fereidoon

    2011-05-11

    The effect of roasting on the content of phenolic compounds and antioxidant properties of cashew nuts and testa was studied. Whole cashew nuts, subjected to low-temperature (LT) and high-temperature (HT) treatments, were used to determine the antioxidant activity of products. Antioxidant activities of cashew nut, kernel, and testa phenolics extracted increased as the roasting temperature increased. The highest activity, as determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, oxygen radical absorbance capacity (ORAC), hydroxyl radical scavenging capacity, Trolox equivalent antioxidant activity (TEAC), and reducing power, was achieved when nuts were roasted at 130 °C for 33 min. Furthermore, roasting increased the total phenolic content (TPC) in both the soluble and bound extracts from whole nut, kernel, and testa but decreased that of the proanthocyanidins (PC) except for the soluble extract of cashew kernels. In addition, cashew testa afforded a higher extract yield, TPC, and PC in both soluble and bound fractions compared to that in whole nuts and kernels. Phenolic acids, namely, syringic (the predominant one), gallic, and p-coumaric acids, were identified. Flavonoids, namely, (+)-catechin, (-)-epicatechin, and epigallocatechin, were also identified, and their contents increased with increasing temperature. The results so obtained suggest that HT-short time (HTST) roasting effectively enhances the antioxidant activity of cashew nuts and testa.

  17. Polarization Aberrations

    NASA Technical Reports Server (NTRS)

    Mcguire, James P., Jr.; Chipman, Russell A.

    1990-01-01

    The analysis of the polarization characteristics displayed by optical systems can be divided into two categories: geometrical and physical. Geometrical analysis calculates the change in polarization of a wavefront between pupils in an optical instrument. Physical analysis propagates the polarized fields wherever the geometrical analysis is not valid, i.e., near the edges of stops, near images, in anisotropic media, etc. Polarization aberration theory provides a starting point for geometrical design and facilitates subsequent optimization. The polarization aberrations described arise from differences in the transmitted (or reflected) amplitudes and phases at interfaces. The polarization aberration matrix (PAM) is calculated for isotropic rotationally symmetric systems through fourth order and includes the interface phase, amplitude, linear diattenuation, and linear retardance aberrations. The exponential form of Jones matrices used are discussed. The PAM in Jones matrix is introduced. The exact calculation of polarization aberrations through polarization ray tracing is described. The report is divided into three sections: I. Rotationally Symmetric Optical Systems; II. Tilted and Decentered Optical Systems; and Polarization Analysis of LIDARs.

  18. Skew aberration: a form of polarization aberration.

    PubMed

    Yun, Garam; Crabtree, Karlton; Chipman, Russell A

    2011-10-15

    We define a new class of aberration, skew aberration, which is a component of polarization aberration. Skew aberration is an intrinsic rotation of polarization states due to the geometric transformation of local coordinates, independent of coatings and interface polarization. Skew aberration in a radially symmetric system has the form of a circular retardance tilt plus coma aberration. Skew aberration causes undesired polarization distribution in the exit pupil. We demonstrate statistics on skew aberration of 2383 optical systems described in Code V's U.S. patent library [Code V Version 10.3 (Synopsys, 2011), pp. 22-24]; the mean skew aberration is 0.89° and the standard deviation is 1.37°. The maximum skew aberration found is 17.45° and the minimum is -11.33°. U.S. patent 2,896,506, which has ±7.01° of skew aberration, is analyzed in detail. Skew aberration should be of concern in microlithography optics and other high NA and large field of view optical systems.

  19. The role of the testa during development and in establishment of dormancy of the legume seed

    PubMed Central

    Smýkal, Petr; Vernoud, Vanessa; Blair, Matthew W.; Soukup, Aleš; Thompson, Richard D.

    2014-01-01

    Timing of seed germination is one of the key steps in plant life cycles. It determines the beginning of plant growth in natural or agricultural ecosystems. In the wild, many seeds exhibit dormancy and will only germinate after exposure to certain environmental conditions. In contrast, crop seeds germinate as soon as they are imbibed usually at planting time. These domestication-triggered changes represent adaptations to cultivation and human harvesting. Germination is one of the common sets of traits recorded in different crops and termed the “domestication syndrome.” Moreover, legume seed imbibition has a crucial role in cooking properties. Different seed dormancy classes exist among plant species. Physical dormancy (often called hardseededness), as found in legumes, involves the development of a water-impermeable seed coat, caused by the presence of phenolics- and suberin-impregnated layers of palisade cells. The dormancy release mechanism primarily involves seed responses to temperature changes in the habitat, resulting in testa permeability to water. The underlying genetic controls in legumes have not been identified yet. However, positive correlation was shown between phenolics content (e.g., pigmentation), the requirement for oxidation and the activity of catechol oxidase in relation to pea seed dormancy, while epicatechin levels showed a significant positive correlation with soybean hardseededness. myeloblastosis family of transcription factors, WD40 proteins and enzymes of the anthocyanin biosynthesis pathway were involved in seed testa color in soybean, pea and Medicago, but were not tested directly in relation to seed dormancy. These phenolic compounds play important roles in defense against pathogens, as well as affecting the nutritional quality of products, and because of their health benefits, they are of industrial and medicinal interest. In this review, we discuss the role of the testa in mediating legume seed germination, with a focus on

  20. [Efficacy of the program "Testas's (mis)adventures" to promote the deep approach to learning].

    PubMed

    Rosário, Pedro; González-Pienda, Julio Antonio; Cerezo, Rebeca; Pinto, Ricardo; Ferreira, Pedro; Abilio, Lourenço; Paiva, Olimpia

    2010-11-01

    This paper provides information about the efficacy of a tutorial training program intended to enhance elementary fifth graders' study processes and foster their deep approaches to learning. The program "Testas's (mis)adventures" consists of a set of books in which Testas, a typical student, reveals and reflects upon his life experiences during school years. These life stories are nothing but an opportunity to present and train a wide range of learning strategies and self-regulatory processes, designed to insure students' deeper preparation for present and future learning challenges. The program has been developed along a school year, in a one hour weekly tutorial sessions. The training program had a semi-experimental design, included an experimental group (n=50) and a control one (n=50), and used pre- and posttest measures (learning strategies' declarative knowledge, learning approaches and academic achievement). Data suggest that the students enrolled in the training program, comparing with students in the control group, showed a significant improvement in their declarative knowledge of learning strategies and in their deep approach to learning, consequently lowering their use of a surface approach. In spite of this, in what concerns to academic achievement, no statistically significant differences have been found.

  1. Alteration of flavonoid accumulation patterns in transparent testa mutants disturbs auxin transport, gravity responses, and imparts long-term effects on root and shoot architecture.

    PubMed

    Buer, Charles S; Kordbacheh, Farzanah; Truong, Thy T; Hocart, Charles H; Djordjevic, Michael A

    2013-07-01

    Flavonoids have broad cross-kingdom biological activity. In Arabidopsis, flavonoid accumulation in specific tissues, notably the root elongation zone and root/shoot junction modulate auxin transport, affect root gravitropism, and influence overall plant architecture. The relative contribution made by aglycones and their glycosides remains undetermined, and the longer-term phenotypic effects of altered flavonoid accumulation are not fully assessed. We tested Arabidopsis thaliana mutants that accumulate different flavonoids to determine which flavonoids were causing these affects. Tandem mass spectrometry and in situ fluorescence localisation were used to determine the in vivo levels of aglycones in specific tissues of 11 transparent testa mutants. We measured rootward and shootward auxin transport, gravitropic responses, and identified the long-term changes to root and shoot architecture. Unexpected aglycone species accumulated in vivo in several flavonoid-pathway mutants, and lower aglycone levels occurred in transcription factor mutants. Mutants accumulating more quercetin and quercetin-glycosides changed the greatest in auxin transport, gravitropism, and aerial tissue growth. Early flavonoid-pathway mutants showed aberrant lateral root initiation patterns including clustered lateral root initiations at a single site. Transcription factor mutants had multiple phenotypes including shallow root systems. These results confirm that aglycones are present at very low levels, show that lateral root initiation is perturbed in early flavonoid-pathway mutants, and indicate that altered flavonoid accumulation affects multiple aspects of plant architecture.

  2. Chicago aberration correction work.

    PubMed

    Beck, V D

    2012-12-01

    The author describes from his personal involvement the many improvements to electron microscopy Albert Crewe and his group brought by minimizing the effects of aberrations. The Butler gun was developed to minimize aperture aberrations in a field emission electron gun. In the 1960s, Crewe anticipated using a spherical aberration corrector based on Scherzer's design. Since the tolerances could not be met mechanically, a method of moving the center of the octopoles electrically was developed by adding lower order multipole fields. Because the corrector was located about 15 cm ahead of the objective lens, combination aberrations would arise with the objective lens. This fifth order aberration would then limit the aperture of the microscope. The transformation of the off axis aberration coefficients of a round lens was developed and a means to cancel anisotropic coma was developed. A new method of generating negative spherical aberration was invented using the combination aberrations of hexapoles. Extensions of this technique to higher order aberrations were developed. An electrostatic electron mirror was invented, which allows the cancellation of primary spherical aberration and first order chromatic aberration. A reduction of chromatic aberration by two orders of magnitude was demonstrated using such a system.

  3. Roles of the GLABROUS1 and TRANSPARENT TESTA GLABRA Genes in Arabidopsis Trichome Development.

    PubMed Central

    Larkin, J. C.; Oppenheimer, D. G.; Lloyd, A. M.; Paparozzi, E. T.; Marks, M. D.

    1994-01-01

    Arabidopsis trichomes are branched, single-celled epidermal hairs. These specialized cells provide a convenient model for investigating the specification of cell fate in plants. Two key genes regulating the initiation of trichome development are GLABROUS1 (GL1) and TRANSPARENT TESTA GLABRA (TTG). GL1 is a member of the myb gene family. The maize R gene, which can functionally complement the Arabidopsis ttg mutation, encodes a basic helix-loop-helix protein. We used constitutively expressed copies of the GL1 and R genes to test hypotheses about the roles of GL1 and TTG in trichome development. The results support the hypothesis that TTG and GL1 cooperate at the same point in the trichome developmental pathway. Furthermore, the constitutive expression of both GL1 and R in the same plant caused trichomes to develop on all shoot epidermal surfaces. Results were also obtained indicating that TTG plays an additional role in inhibiting neighboring cells from becoming trichomes. PMID:12244266

  4. Metabolite profiling of somatic embryos of Cyclamen persicum in comparison to zygotic embryos, endosperm, and testa

    PubMed Central

    Winkelmann, Traud; Ratjens, Svenja; Bartsch, Melanie; Rode, Christina; Niehaus, Karsten; Bednarz, Hanna

    2015-01-01

    Somatic embryogenesis has been shown to be an efficient in vitro plant regeneration system for many crops such as the important ornamental plant Cyclamen persicum, for which this regeneration pathway of somatic embryogenesis is of interest for the vegetative propagation of parental lines as well as elite plants. However, somatic embryogenesis is not commercially used in many crops due to several unsolved problems, such as malformations, asynchronous development, deficiencies in maturation and germination of somatic embryos. In contrast, zygotic embryos in seeds develop and germinate without abnormalities in most cases. Instead of time-consuming and labor-intensive experiments involving tests of different in vitro culture conditions and plant growth regulator supplements, we follow a more directed approach. Zygotic embryos served as a reference and were compared to somatic embryos in metabolomic analyses allowing the future optimization of the in vitro system. The aims of this study were to detect differences in the metabolite profiles of torpedo stage somatic and zygotic embryos of C. persicum. Moreover, major metabolites in endosperm and testa were identified and quantified. Two sets of extracts of two to four biological replicates each were analyzed. In total 52 metabolites were identified and quantified in the different tissues. One of the most significant differences between somatic and zygotic embryos was that the proline concentration in the zygotic embryos was about 40 times higher than that found in somatic embryos. Epicatechin, a scavenger for reactive oxygen species, was found in highest abundance in the testa. Sucrose, the most abundant metabolite was detected in significantly higher concentrations in zygotic embryos. Also, a yet unknown trisaccharide, was significantly enriched in zygotic embryos. PMID:26300898

  5. Interpreting Chromosome Aberration Spectra

    NASA Technical Reports Server (NTRS)

    Levy, Dan; Reeder, Christopher; Loucas, Bradford; Hlatky, Lynn; Chen, Allen; Cornforth, Michael; Sachs, Rainer

    2007-01-01

    Ionizing radiation can damage cells by breaking both strands of DNA in multiple locations, essentially cutting chromosomes into pieces. The cell has enzymatic mechanisms to repair such breaks; however, these mechanisms are imperfect and, in an exchange process, may produce a large-scale rearrangement of the genome, called a chromosome aberration. Chromosome aberrations are important in killing cells, during carcinogenesis, in characterizing repair/misrepair pathways, in retrospective radiation biodosimetry, and in a number of other ways. DNA staining techniques such as mFISH ( multicolor fluorescent in situ hybridization) provide a means for analyzing aberration spectra by examining observed final patterns. Unfortunately, an mFISH observed final pattern often does not uniquely determine the underlying exchange process. Further, resolution limitations in the painting protocol sometimes lead to apparently incomplete final patterns. We here describe an algorithm for systematically finding exchange processes consistent with any observed final pattern. This algorithm uses aberration multigraphs, a mathematical formalism that links the various aspects of aberration formation. By applying a measure to the space of consistent multigraphs, we will show how to generate model-specific distributions of aberration processes from mFISH experimental data. The approach is implemented by software freely available over the internet. As a sample application, we apply these algorithms to an aberration data set, obtaining a distribution of exchange cycle sizes, which serves to measure aberration complexity. Estimating complexity, in turn, helps indicate how damaging the aberrations are and may facilitate identification of radiation type in retrospective biodosimetry.

  6. Calibration and first light of the Diabolo photometer at the Millimetre and Infrared Testa Grigia Observatory

    NASA Astrophysics Data System (ADS)

    Benoit, A.; Zagury, F.; Coron, N.; De Petris, M.; Désert, F.-X.; Giard, M.; Bernard, J.-P.; Crussaire, J.-P.; Dambier, G.; de Bernardis, P.; Delabrouille, J.; De Luca, A.; de Marcillac, P.; Jegoudez, G.; Lamarre, J.-M.; Leblanc, J.; Lepeltier, J.-P.; Leriche, B.; Mainella, G.; Narbonne, J.; Pajot, F.; Pons, R.; Puget, J.-L.; Pujol, S.; Recouvreur, G.; Serra, G.; Soglasnova, V.; Torre, J.-P.; Vozzi, B.

    2000-02-01

    We have designed and built a large-throughput dual channel photometer, Diabolo. This photometer is dedicated to the observation of millimetre continuum diffuse sources, and in particular, of the Sunyaev-Zel'dovich effect and of anisotropies of the 3 K background. We describe the optical layout and filtering system of the instrument, which uses two bolometric detectors for simultaneous observations in two frequency channels at 1.2 and 2.1 mm. The bolometers are cooled to a working temperature of 0.1 K provided by a compact dilution cryostat. The photometric and angular responses of the instrument are measured in the laboratory. First astronomical light was detected in March 1995 at the focus of the new Millimetre and Infrared Testa Grigia Observatory (MITO) Telescope. The established sensitivity of the system is of 7 mKRJ\\ s1/2. For a typical map of at least 10 beams, with one hour of integration per beam, one can achieve the rms values of y_SZ =~ 7\\ 10-5 and the 3 K background anisotropy {Delta T/ T} =~ 7\\ 10-5, in winter conditions. We also report on a novel bolometer AC readout circuit which allows for the first time total power measurements on the sky. This technique alleviates (but does not forbid) the use of chopping with a secondary mirror. This technique and the dilution fridge concept will be used in future scan-modulated space instrument like the ESA Planck mission project.

  7. TRANSPARENT TESTA GLABRA1 and GLABRA1 Compete for Binding to GLABRA3 in Arabidopsis

    PubMed Central

    Pesch, Martina; Schultheiß, Ilka; Klopffleisch, Karsten; Clemen, Christoph S.; Hülskamp, Martin

    2015-01-01

    The MBW (for R2R3MYB, basic helix-loop-helix [bHLH], and WD40) genes comprise an evolutionarily conserved gene cassette that regulates several traits such as (pro)anthocyanin and anthocyanin biosynthesis and epidermal cell differentiation in plants. Trichome differentiation in Arabidopsis (Arabidopsis thaliana) is governed by GLABRA1 (GL1; R2R3MYB), GL3 (bHLH), and TRANSPARENT TESTA GLABRA1 (TTG1; WD40). They are thought to form a trimeric complex that acts as a transcriptional activation complex. We provide evidence that these three MBW proteins form either GL1 GL3 or GL3 TTG1 dimers. The formation of each dimer is counteracted by the respective third protein in yeast three-hybrid assays, pulldown experiments (luminescence-based mammalian interactome), and fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer studies. We further show that two target promoters, TRIPTYCHON (TRY) and CAPRICE (CPC), are differentially regulated: GL1 represses the activation of the TRY promoter by GL3 and TTG1, and TTG1 suppresses the activation of the CPC promoter by GL1 and GL3. Our data suggest that the transcriptional activation by the MBW complex involves alternative complex formation and that the two dimers can differentially regulate downstream genes. PMID:25926482

  8. TRANSPARENT TESTA GLABRA1 and GLABRA1 Compete for Binding to GLABRA3 in Arabidopsis.

    PubMed

    Pesch, Martina; Schultheiß, Ilka; Klopffleisch, Karsten; Uhrig, Joachim F; Koegl, Manfred; Clemen, Christoph S; Simon, Rüdiger; Weidtkamp-Peters, Stefanie; Hülskamp, Martin

    2015-06-01

    The MBW (for R2R3MYB, basic helix-loop-helix [bHLH], and WD40) genes comprise an evolutionarily conserved gene cassette that regulates several traits such as (pro)anthocyanin and anthocyanin biosynthesis and epidermal cell differentiation in plants. Trichome differentiation in Arabidopsis (Arabidopsis thaliana) is governed by GLABRA1 (GL1; R2R3MYB), GL3 (bHLH), and transparent TESTA GLABRA1 (TTG1; WD40). They are thought to form a trimeric complex that acts as a transcriptional activation complex. We provide evidence that these three MBW proteins form either GL1 GL3 or GL3 TTG1 dimers. The formation of each dimer is counteracted by the respective third protein in yeast three-hybrid assays, pulldown experiments (luminescence-based mammalian interactome), and fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer studies. We further show that two target promoters, Triptychon (TRY) and CAPRICE (CPC), are differentially regulated: GL1 represses the activation of the TRY promoter by GL3 and TTG1, and TTG1 suppresses the activation of the CPC promoter by GL1 and GL3. Our data suggest that the transcriptional activation by the MBW complex involves alternative complex formation and that the two dimers can differentially regulate downstream genes.

  9. Optical advantages of astigmatic aberration corrected heliostats

    NASA Astrophysics Data System (ADS)

    van Rooyen, De Wet; Schöttl, Peter; Bern, Gregor; Heimsath, Anna; Nitz, Peter

    2016-05-01

    Astigmatic aberration corrected heliostats adapt their shape in dependence of the incidence angle of the sun on the heliostat. Simulations show that this optical correction leads to a higher concentration ratio at the target and thus in a decrease in required receiver aperture in particular for smaller heliostat fields.

  10. Transcranial phase aberration correction using beam simulations and MR-ARFI

    SciTech Connect

    Vyas, Urvi Kaye, Elena; Pauly, Kim Butts

    2014-03-15

    Purpose: Transcranial magnetic resonance-guided focused ultrasound surgery is a noninvasive technique for causing selective tissue necrosis. Variations in density, thickness, and shape of the skull cause aberrations in the location and shape of the focal zone. In this paper, the authors propose a hybrid simulation-MR-ARFI technique to achieve aberration correction for transcranial MR-guided focused ultrasound surgery. The technique uses ultrasound beam propagation simulations with MR Acoustic Radiation Force Imaging (MR-ARFI) to correct skull-caused phase aberrations. Methods: Skull-based numerical aberrations were obtained from a MR-guided focused ultrasound patient treatment and were added to all elements of the InSightec conformal bone focused ultrasound surgery transducer during transmission. In the first experiment, the 1024 aberrations derived from a human skull were condensed into 16 aberrations by averaging over the transducer area of 64 elements. In the second experiment, all 1024 aberrations were applied to the transducer. The aberrated MR-ARFI images were used in the hybrid simulation-MR-ARFI technique to find 16 estimated aberrations. These estimated aberrations were subtracted from the original aberrations to result in the corrected images. Each aberration experiment (16-aberration and 1024-aberration) was repeated three times. Results: The corrected MR-ARFI image was compared to the aberrated image and the ideal image (image with zero aberrations) for each experiment. The hybrid simulation-MR-ARFI technique resulted in an average increase in focal MR-ARFI phase of 44% for the 16-aberration case and 52% for the 1024-aberration case, and recovered 83% and 39% of the ideal MR-ARFI phase for the 16-aberrations and 1024-aberration case, respectively. Conclusions: Using one MR-ARFI image and noa priori information about the applied phase aberrations, the hybrid simulation-MR-ARFI technique improved the maximum MR-ARFI phase of the beam's focus.

  11. Individual eye model based on wavefront aberration

    NASA Astrophysics Data System (ADS)

    Guo, Huanqing; Wang, Zhaoqi; Zhao, Qiuling; Quan, Wei; Wang, Yan

    2005-03-01

    Based on the widely used Gullstrand-Le Grand eye model, the individual human eye model has been established here, which has individual corneal data, anterior chamber depth and the eyeball depth. Furthermore, the foremost thing is that the wavefront aberration calculated from the individual eye model is equal to the eye's wavefront aberration measured with the Hartmann-shack wavefront sensor. There are four main steps to build the model. Firstly, the corneal topography instrument was used to measure the corneal surfaces and depth. And in order to input cornea into the optical model, high-order aspheric surface-Zernike Fringe Sag surface was chosen to fit the corneal surfaces. Secondly, the Hartmann-shack wavefront sensor, which can offer the Zernike polynomials to describe the wavefront aberration, was built to measure the wavefront aberration of the eye. Thirdly, the eye's axial lengths among every part were measured with A-ultrasonic technology. Then the data were input into the optical design software-ZEMAX and the crystalline lens's shapes were optimized with the aberration as the merit function. The individual eye model, which has the same wavefront aberrations with the real eye, is established.

  12. Line of Sight of an Aberrated Optical System

    DTIC Science & Technology

    2008-10-24

    8217 4. TITLE (and &"do) TYEO’lEOTAeEID)OEE LIME OF SIGHT OF AN ABERRATED _____________ OPTICAL SYTE S. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(&) I...aberration across its interior regardless of Q shape. Next, an optical system with aberrated but uniformly illuminated annular pupil is considered. The...and R a 21! [sn Mwh, Q ; C) +cosO _9W(h,6; C) 1 id ~ 2b111J J (h) sin h h d8, (2b where E -R2W! I(h) hdh de (30) Ca -15- We now expand the aberration

  13. Mast cell-dependent allergic responses are inhibited by ethanolic extract of adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) testa.

    PubMed

    Chen, Hong-Jhang; Shih, Chun-Kuang; Hsu, Hsin-Yi; Chiang, Wenchang

    2010-02-24

    Allergy is an immune dysfunction caused by degranulation from mast cells in the early phase and cytokine secretion in the late phase of the cell. The purpose of this study was to investigate the effects of adlay (Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf) testa against beta-hexosaminidase release as a marker of degranulation in rat basophilic leukemia (RBL)-2H3 cells. The ethyl acetate fraction from ethanolic extracts of adlay testa (ATE-EtOAc) exhibited potent inhibitory activity that suppressed degranulation from RBL-2H3 cells stimulated by 1 microM A23187. The 20%-80% EtOAc/Hex subfractions of ATE-EtOAc significantly inhibited histamine release with a IC(50) of 75-100 microg/mL. In addition, the ATE-EtOAc subfractions suppressed interleukin (IL)-4, IL-6, and tumor necrosis factor-alpha secretion in RBL-2H3 cells, indicating that adlay testa were able to inhibit cytokine secretion. In order to explore the inhibitory mechanism of adlay testa in mast cell degranulation, we examined the activation of intracellular signaling molecules. Adlay testa inhibited the phosphorylation ERK expression. Furthermore, the two major active compounds, 4-hydroxyacetophenone and p-coumaric acid, were isolated from the ATE-EtOAc subfractions. These results suggest that ATE had an inhibitory effect on allergic response via the ERK signaling transduction in RBL-2H3 cells.

  14. Measurement of strontium isotope ratio in nitric acid extract of peanut testa by ICP-Q-MS after removal of Rb by extraction with pure water.

    PubMed

    Zhu, Yanbei; Hioki, Akiharu; Chiba, Koichi

    2014-02-01

    The difference in the distributions of Sr and Rb in peanut seeds was utilized to develop a precise method for Sr isotope ratio measurement by inductively coupled plasma quadruple mass spectrometry (ICP-Q-MS). The testa instead of the whole peanut seed was selected as the sample because apparent enrichment of Sr in comparison to Rb was found in the testa. Furthermore, Rb in the testa was removed by pure water extraction with the aid of sonication to remove the isobaric interference in Sr isotope ratio measurement. The testa taken from one peanut seed was treated as one sample for the analysis. After optimization of the operating conditions, pure water (10 mL for each sample) extraction in 30 min with sonication was able to remove over 95% of Rb in the testa, while after the Rb removal Sr could be completely extracted using 10 mL of 0.3 mol L(-1) HNO3 for each sample. The integration time in ICP-Q-MS measurement was optimized to achieve a lower measurement uncertainty in a shorter time; the results showed that 1s was required and enough for the precise measurement of Sr isotope ratios giving a relative standard uncertainty (n=10) of ca. 0.1%. The present method was applied to peanut seeds grown in Japan, China, USA, India, and South Africa.

  15. High-performance wobbling subreflector for the Millimetre and Infrared Testa Grigia Observatory 2.6-m telescope

    NASA Astrophysics Data System (ADS)

    Mainella, Gianni; de Bernardis, Paolo; de Petris, Marco; Mandiello, Alfonso; Perciballi, Maurizio; Romeo, Gianni

    1996-05-01

    The Millimetre and Infrared Testa Grigia Observatory 2.6-m Cassegrain telescope has been designed to allow high-sensitivity observations in the millimeter spectral range. For this purpose, in order to reduce unwanted contributions from local foregrounds, we adopted a sky-chopping technique, by wobbling the telescope subreflector. We describe the design and performance of the wobbling system, which can endure external forced two and three fields square-wave modulation and includes features such as high frequency, high amplitude, high duty cycle, low microphonics, and high stability. millimeter-wave telescope.

  16. The spherical aberration of the crystalline lens of the human eye.

    PubMed

    Smith, G; Cox, M J; Calver, R; Garner, L F

    2001-01-15

    The in vivo spherical aberration of the lenses of 26 subjects was estimated from the measured total aberration of the eye and that predicted from the measured shape of the anterior corneal surface. Since it was only possible to estimate the aberration contribution from the posterior corneal surface, its value led to an uncertainty in the final aberration level of the lens. For all the subjects and for a wide range of possible aberration levels at the posterior corneal surface, the spherical aberration of the relaxed lens was found to be negative.

  17. Promotion of testa rupture during garden cress germination involves seed compartment-specific expression and activity of pectin methylesterases.

    PubMed

    Scheler, Claudia; Weitbrecht, Karin; Pearce, Simon P; Hampstead, Anthony; Büttner-Mainik, Annette; Lee, Kieran J D; Voegele, Antje; Oracz, Krystyna; Dekkers, Bas J W; Wang, Xiaofeng; Wood, Andrew T A; Bentsink, Leónie; King, John R; Knox, J Paul; Holdsworth, Michael J; Müller, Kerstin; Leubner-Metzger, Gerhard

    2015-01-01

    Pectin methylesterase (PME) controls the methylesterification status of pectins and thereby determines the biophysical properties of plant cell walls, which are important for tissue growth and weakening processes. We demonstrate here that tissue-specific and spatiotemporal alterations in cell wall pectin methylesterification occur during the germination of garden cress (Lepidium sativum). These cell wall changes are associated with characteristic expression patterns of PME genes and resultant enzyme activities in the key seed compartments CAP (micropylar endosperm) and RAD (radicle plus lower hypocotyl). Transcriptome and quantitative real-time reverse transcription-polymerase chain reaction analysis as well as PME enzyme activity measurements of separated seed compartments, including CAP and RAD, revealed distinct phases during germination. These were associated with hormonal and compartment-specific regulation of PME group 1, PME group 2, and PME inhibitor transcript expression and total PME activity. The regulatory patterns indicated a role for PME activity in testa rupture (TR). Consistent with a role for cell wall pectin methylesterification in TR, treatment of seeds with PME resulted in enhanced testa permeability and promoted TR. Mathematical modeling of transcript expression changes in germinating garden cress and Arabidopsis (Arabidopsis thaliana) seeds suggested that group 2 PMEs make a major contribution to the overall PME activity rather than acting as PME inhibitors. It is concluded that regulated changes in the degree of pectin methylesterification through CAP- and RAD-specific PME and PME inhibitor expression play a crucial role during Brassicaceae seed germination.

  18. Aberration Compensation Using Nematic Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Somalingam, S.; Hain, M.; Tschudi, T.; Knittel, J.; Richter, H.

    We have developed a novel transmissive nematic liquid crystal device which is capable of compensating spherical wavefront aberration that occurs during the operation of optical pickup systems. In order to increase the storage capacity, next generation optical data storage systems beyond CD and DVD will use according to the Blu-Ray specification (BD) blue laser light and an objective lens with high numerical aperture (N.A.) of 0.85. However, such high N.A. systems have an inherent higher sensitivity on aberrations. For example spherical aberration is inversely proportional to the wavelength and grows with the fourth power of N.A. of the objective lens. In an optical pickup system there are two sources for spherical aberration: The first one is the variation of the substrate thickness due to manufacturing tolerances under mass production conditions. The second one concerns disks with multiple data-layers, which cause spherical aberration when layers are switched, as the objective lens can only be optimized for a single layer thickness. We report a method for effective compensation of spherical aberration by utilizing a novel liquid crystal device, which generates a parabolic wavefront profile. This particular shape makes the device highly tolerant against lateral movement. A sophisticated electrode design allows us to reduce the number of driving electrodes down to two by using the method of conductive ladder mashing. Further evaluation in a blue-DVD test drive has been carried out with good results. By placing the device into an optical pick-up we were able to readout a dual-layer ROM disk with a total capacity of 50 gigabytes (GB). A data-to-clock jitter of 6.9% for the 80 μm and of 8.0% for the 100 μm cover layer could be realized.

  19. Distribution of the elements in cotyledon, embryonic axis, and testa of peanut seeds obtained by ICP-MS with microwave acid digestion.

    PubMed

    Zhu, Yanbei; Hioki, Akiharu; Chiba, Koichi

    2013-01-01

    Eighteen elements in the cotyledon, the embryonic axis, and the testa of peanut seeds were determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave acid digestion, while the gravimetric standard addition with internal standard was applied for the calibration of the elemental concentrations. The detection limit and the procedure blank value for each element were low enough to ensure the precise analysis of the elements, with a relative expanded uncertainty of less than 5%. The concentrations of the elements in peanut seed samples covered 6 orders of magnitude from approximately 0.01 mg kg(-1) of Co to approximately 7000 mg kg(-1) of K. The correlation coefficient factor was around 0.98 for the elemental concentrations in peanut seeds grown in Japan and those grown in China, indicating a good correlation. Most of the elements distributed in the cotyledon in large amounts because of the cotyledon's relatively high mass fraction. By contrast, Na, Ca, Fe, Co, Ni, Cu, Ga, Sr, Cd, and Ba were apparently enriched in the testa and the relative enrichment factor (REF) values of the elements were over 4. The relative enrichment of Mo, Fe, Zn and other elements was observed in the embryonic axis samples with REF values over 2. The relative enrichment of Cd in the testa of peanut seed indicates that about 15 to 25% of the Cd intake through peanut seeds could be effectively lowered by removal of the testa (roughly 2.5 to 3.5% of the peanut seed).

  20. The Discrepancies between Staff and Students' Perceptions of Feedback and Assessment Practices--Analysis of TESTA Data from One HE Institution

    ERIC Educational Resources Information Center

    Pazio, Monika

    2016-01-01

    Students' satisfaction with feedback and assessment has historically been low. This is confirmed by the most recent National Student Survey where feedback and assessment still remain the area of least satisfaction. Such projects as Transforming the Experience of Students through Assessment (TESTA) attempt to tackle the issue by providing a channel…

  1. Optical aberration compensation in a multiplexed optical trapping system

    NASA Astrophysics Data System (ADS)

    Čižmár, T.; Dalgarno, H. I. C.; Ashok, P. C.; Gunn-Moore, F. J.; Dholakia, K.

    2011-04-01

    In this paper we discuss optical aberrations within a multiplexed optical trapping system. We analyze two of the most powerful methods for optical trap multiplexing: time-shared beam steering and holographic beam shaping in a tandem system with an acousto-optic deflector and spatial light modulator. We show how to isolate and correct for the aberrations introduced by these individual optical components using the spatial light modulator and demonstrate the enhancement this provides to optical trapping.

  2. Mutations in UDP-Glucose:sterol glucosyltransferase in Arabidopsis cause transparent testa phenotype and suberization defect in seeds.

    PubMed

    DeBolt, Seth; Scheible, Wolf-Rüdiger; Schrick, Kathrin; Auer, Manfred; Beisson, Fred; Bischoff, Volker; Bouvier-Navé, Pierrette; Carroll, Andrew; Hematy, Kian; Li, Yonghua; Milne, Jennifer; Nair, Meera; Schaller, Hubert; Zemla, Marcin; Somerville, Chris

    2009-09-01

    In higher plants, the most abundant sterol derivatives are steryl glycosides (SGs) and acyl SGs. Arabidopsis (Arabidopsis thaliana) contains two genes, UGT80A2 and UGT80B1, that encode UDP-Glc:sterol glycosyltransferases, enzymes that catalyze the synthesis of SGs. Lines having mutations in UGT80A2, UGT80B1, or both UGT80A2 and UGT8B1 were identified and characterized. The ugt80A2 lines were viable and exhibited relatively minor effects on plant growth. Conversely, ugt80B1 mutants displayed an array of phenotypes that were pronounced in the embryo and seed. Most notable was the finding that ugt80B1 was allelic to transparent testa15 and displayed a transparent testa phenotype and a reduction in seed size. In addition to the role of UGT80B1 in the deposition of flavanoids, a loss of suberization of the seed was apparent in ugt80B1 by the lack of autofluorescence at the hilum region. Moreover, in ugt80B1, scanning and transmission electron microscopy reveals that the outer integument of the seed coat lost the electron-dense cuticle layer at its surface and displayed altered cell morphology. Gas chromatography coupled with mass spectrometry of lipid polyester monomers confirmed a drastic decrease in aliphatic suberin and cutin-like polymers that was associated with an inability to limit tetrazolium salt uptake. The findings suggest a membrane function for SGs and acyl SGs in trafficking of lipid polyester precursors. An ancillary observation was that cellulose biosynthesis was unaffected in the double mutant, inconsistent with a predicted role for SGs in priming cellulose synthesis.

  3. Image Ellipticity from Atmospheric Aberrations

    SciTech Connect

    de Vries, W H; Olivier, S S; Asztalos, S J; Rosenberg, L J; Baker, K L

    2007-03-06

    We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand the errors in shape measurements of astronomical objects, such as those used to study weak gravitational lensing of field galaxies. The PSF modeling involves either a Fourier transform of the phase information in the pupil plane or a ray-tracing approach, which has the advantage of requiring fewer computations than the Fourier transform. Using a standard method, involving the Gaussian weighted second moments of intensity, we then calculate the ellipticity of the PSF patterns. We find significant ellipticity for the instantaneous patterns (up to more than 10%). Longer exposures, which we approximate by combining multiple (N) images from uncorrelated atmospheric realizations, yield progressively lower ellipticity (as 1/{radical}N). We also verify that the measured ellipticity does not depend on the sampling interval in the pupil plane using the Fourier method. However, we find that the results using the ray-tracing technique do depend on the pupil sampling interval, representing a gradual breakdown of the geometric approximation at high spatial frequencies. Therefore, ray tracing is generally not an accurate method of modeling PSF ellipticity induced by atmospheric turbulence unless some additional procedure is implemented to correctly account for the effects of high spatial frequency aberrations. The Fourier method, however, can be used directly to accurately model PSF ellipticity, which can give insights into errors in the statistics of field galaxy shapes used in studies of weak gravitational lensing.

  4. TRANSPARENT TESTA GLABRA 1 ubiquitously regulates plant growth and development from Arabidopsis to foxtail millet (Setaria italica).

    PubMed

    Liu, Kaige; Qi, Shuanghui; Li, Dong; Jin, Changyu; Gao, Chenhao; Duan, Shaowei; Feng, Baili; Chen, Mingxun

    2017-01-01

    TRANSPARENT TESTA GLABRA 1 of Arabidopsis thaliana (AtTTG1) is a WD40 repeat transcription factor that plays multiple roles in plant growth and development, particularly in seed metabolite production. In the present study, to determine whether SiTTG1 of the phylogenetically distant monocot foxtail millet (Setaria italica) has similar functions, we used transgenic Arabidopsis and Nicotiana systems to explore its activities. We found that SiTTG1 functions as a transcription factor. Overexpression of the SiTTG1 gene rescued many of the mutant phenotypes in Arabidopsis ttg1-13 plants. Additionally, SiTTG1 overexpression fully corrected the reduced expression of mucilage biosynthetic genes, and the induced expression of genes involved in accumulation of seed fatty acids and storage proteins in developing seeds of ttg1-13 plants. Ectopic expression of SiTTG1 restored the sensitivity of the ttg1-13 mutant to salinity and high glucose stresses during germination and seedling establishment, and restored altered expression levels of some stress-responsive genes in ttg1-13 seedlings to the wild type level under salinity and glucose stresses. Our results provide information that will be valuable for understanding the function of TTG1 from monocot to dicot species and identifying a promising target for genetic manipulation of foxtail millet to improve the amount of seed metabolites.

  5. Transparent testa16 plays multiple roles in plant development and is involved in lipid synthesis and embryo development in canola.

    PubMed

    Deng, Wei; Chen, Guanqun; Peng, Fred; Truksa, Martin; Snyder, Crystal L; Weselake, Randall J

    2012-10-01

    Transparent Testa16 (TT16), a transcript regulator belonging to the B(sister) MADS box proteins, regulates proper endothelial differentiation and proanthocyanidin accumulation in the seed coat. Our understanding of its other physiological roles, however, is limited. In this study, the physiological and developmental roles of TT16 in an important oil crop, canola (Brassica napus), were dissected by a loss-of-function approach. RNA interference (RNAi)-mediated down-regulation of tt16 in canola caused dwarf phenotypes with a decrease in the number of inflorescences, flowers, siliques, and seeds. Fluorescence microscopy revealed that tt16 deficiency affects pollen tube guidance, resulting in reduced fertility and negatively impacting embryo and seed development. Moreover, Bntt16 RNAi plants had reduced oil content and altered fatty acid composition. Transmission electron microscopy showed that the seeds of the RNAi plants had fewer oil bodies than the nontransgenic plants. In addition, tt16 RNAi transgenic lines were more sensitive to auxin. Further analysis by microarray showed that tt16 down-regulation alters the expression of genes involved in gynoecium and embryo development, lipid metabolism, auxin transport, and signal transduction. The broad regulatory function of TT16 at the transcriptional level may explain the altered phenotypes observed in the transgenic lines. Overall, the results uncovered important biological roles of TT16 in plant development, especially in fatty acid synthesis and embryo development.

  6. Camera processing with chromatic aberration.

    PubMed

    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.

  7. Chromosome Aberrations in Astronauts

    NASA Technical Reports Server (NTRS)

    George, Kerry A.; Durante, M.; Cucinotta, Francis A.

    2007-01-01

    A review of currently available data on in vivo induced chromosome damage in the blood lymphocytes of astronauts proves that, after protracted exposure of a few months or more to space radiation, cytogenetic biodosimetry analyses of blood collected within a week or two of return from space provides a reliable estimate of equivalent radiation dose and risk. Recent studies indicate that biodosimetry estimates from single spaceflights lie within the range expected from physical dosimetry and biophysical models, but very large uncertainties are associated with single individual measurements and the total sample population remains low. Retrospective doses may be more difficult to estimate because of the fairly rapid time-dependent loss of "stable" aberrations in blood lymphocytes. Also, biodosimetry estimates from individuals who participate in multiple missions, or very long (interplanetary) missions, may be complicated by an adaptive response to space radiation and/or changes in lymphocyte survival and repopulation. A discussion of published data is presented and specific issues related to space radiation biodosimetry protocols are discussed.

  8. Correction of Distributed Optical Aberrations

    SciTech Connect

    Baker, K; Olivier, S; Carrano, C; Phillion, D

    2006-02-12

    The objective of this project was to demonstrate the use of multiple distributed deformable mirrors (DMs) to improve the performance of optical systems with distributed aberrations. This concept is expected to provide dramatic improvement in the optical performance of systems in applications where the aberrations are distributed along the optical path or within the instrument itself. Our approach used multiple actuated DMs distributed to match the aberration distribution. The project developed the algorithms necessary to determine the required corrections and simulate the performance of these multiple DM systems.

  9. Lesion generation through ribs using histotripsy therapy without aberration correction.

    PubMed

    Kim, Yohan; Wang, Tzu-Yin; Xu, Zhen; Cain, Charles A

    2011-11-01

    This study investigates the feasibility of using high-intensity pulsed therapeutic ultrasound, or histotripsy, to non-invasively generate lesions through the ribs. Histotripsy therapy mechanically ablates tissue through the generation of a cavitation bubble cloud, which occurs when the focal pressure exceeds a certain threshold. We hypothesize that histotripsy can generate precise lesions through the ribs without aberration correction if the main lobe retains its shape and exceeds the cavitation initiation threshold and the secondary lobes remain below the threshold. To test this hypothesis, a 750-kHz focused transducer was used to generate lesions in tissue-mimicking phantoms with and without the presence of rib aberrators. In all cases, 8000 pulses with 16 to 18 MPa peak rarefactional pressure at a repetition frequency of 100 Hz were applied without aberration correction. Despite the high secondary lobes introduced by the aberrators, high-speed imaging showed that bubble clouds were generated exclusively at the focus, resulting in well-confined lesions with comparable dimensions. Collateral damage from secondary lobes was negligible, caused by single bubbles that failed to form a cloud. These results support our hypothesis, suggesting that histotripsy has a high tolerance for aberrated fields and can generate confined focal lesions through rib obstacles without aberration correction.

  10. Lesion Generation Through Ribs Using Histotripsy Therapy Without Aberration Correction

    PubMed Central

    Kim, Yohan; Wang, Tzu-Yin; Xu, Zhen; Cain, Charles A.

    2012-01-01

    This study investigates the feasibility of using high-intensity pulsed therapeutic ultrasound, or histotripsy, to non-invasively generate lesions through the ribs. Histotripsy therapy mechanically ablates tissue through the generation of a cavitation bubble cloud, which occurs when the focal pressure exceeds a certain threshold. We hypothesize that histotripsy can generate precise lesions through the ribs without aberration correction if the main lobe retains its shape and exceeds the cavitation initiation threshold and the secondary lobes remain below the threshold. To test this hypothesis, a 750-kHz focused transducer was used to generate lesions in tissue-mimicking phantoms with and without the presence of rib aberrators. In all cases, 8000 pulses with 16 to 18 MPa peak rarefactional pressure at a repetition frequency of 100 Hz were applied without aberration correction. Despite the high secondary lobes introduced by the aberrators, high-speed imaging showed that bubble clouds were generated exclusively at the focus, resulting in well-confined lesions with comparable dimensions. Collateral damage from secondary lobes was negligible, caused by single bubbles that failed to form a cloud. These results support our hypothesis, suggesting that histotripsy has a high tolerance for aberrated fields and can generate confined focal lesions through rib obstacles without aberration correction. PMID:22083767

  11. Theoretical estimates of spherical and chromatic aberration in photoemission electron microscopy.

    PubMed

    Fitzgerald, J P S; Word, R C; Könenkamp, R

    2016-01-01

    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.

  12. Molecular cloning, expression analysis and subcellular localization of a Transparent Testa 12 ortholog in brown cotton (Gossypium hirsutum L.).

    PubMed

    Gao, Jun-Shan; Wu, Nan; Shen, Zhi-Lin; Lv, Kai; Qian, Sen-He; Guo, Ning; Sun, Xu; Cai, Yong-Ping; Lin, Yi

    2016-02-01

    Transparent Testa 12 (TT12) is a kind of transmembrane transporter of proanthocyanidins (PAs), which belongs to a membrane-localized multidrug and toxin efflux (MATE) family, but the molecular basis of PAs transport is still poorly understood. Here, we cloned a full-length TT12 cDNA from the fiber of brown cotton (Gossypium hirsutum), named GhTT12 (GenBank accession No. KF240564), which comprised 1733 bp with an open reading frame (ORF) of 1503 bp and encoded a putative protein containing 500 amino acid residues with a typical MATE conserved domain. The GhTT12 gene had 96.8% similarity to AA genome in Gossypium arboretum. Quantitative RT-PCR analysis denoted that the relative expression of GhTT12 in brown cotton was 1-5 folds higher than that in white cotton. The mRNA level was the highest at 5 days post anthesis (DPA) and reduced gradually during the fiber development. Expressing GhTT12-fused green fluorescent protein (GFP) in Nicotiana tabacum showed that GhTT12-GFP was localized in the vacuole membrane. The content of PAs increased firstly and decreased afterwards, and reached the maximum at 15 DPA in brown cotton. But for white cotton, the content of PAs remained at a low level during the fiber development. We speculate that GhTT12 may participate in the transportation of PAs from the cytoplasmic matrix to the vacuole. Taken together, our data revealed that GhTT12 was functional as a PAs transmembrane transporter.

  13. Evaluation of nutritional quality of dried cashew nut testa using laboratory rat as a model for pigs.

    PubMed

    Donkoh, Armstrong; Attoh-Kotoku, Victoria; Osei Kwame, Reginald; Gascar, Richard

    2012-01-01

    Dried cashew nut testa (DCNT) was characterized with respect to proximate, mineral, and energy profile. The crude protein, crude fibre, and fat and ash contents were, in g kg(-1)DM, 190.0, 103.0, 20.1, and 20.2, respectively, with metabolizable energy of 7.12 MJ kg(-1) DM. In a feeding trial, isoproteic diets containing DCNT (O, 50, 100, and 150 g kg(-1)) were fed ad libitum to 4 groups of Sprague-Dawley male rats (110 g body weight, n = 20) for a period of 4 weeks. The rats, used as model for pigs, had free access to water. As the dietary DCNT content was increased from 0 to 150 g kg(-1), there was a significant (P < 0.01) decrease in feed intake (r = -0.99), water intake (r = -0.87), and a reduction in body weight gain (r = -0.93) and efficiency of feed utilization (r = 0.78). However, no deaths or health-related problems were recorded during the study. Dietary treatments had no impact on liver, heart, lungs, kidneys, and intestinal weights. Cost per gram feed and feed cost per gram live weight gain were reduced when DCNT was used. The experimental diet containing 50 g DCNT kg(-1) supported the best growth performance with the lowest feed cost per gram live weight gain of GH¢0.18. Seasonal increases in the prices of conventional feedstuffs like maize and fishmeal would make the use of agroindustrial by-products such as DCNT in pig diets even more attractive.

  14. TRANSPARENT TESTA 12 genes from Brassica napus and parental species: cloning, evolution, and differential involvement in yellow seed trait.

    PubMed

    Chai, You-Rong; Lei, Bo; Huang, Hua-Lei; Li, Jia-Na; Yin, Jia-Ming; Tang, Zhang-Lin; Wang, Rui; Chen, Li

    2009-01-01

    Molecular dissection of the Brassica yellow seed trait has been the subject of intense investigation. Arabidopsis thaliana TRANSPARENT TESTA 12 (AtTT12) encodes a multidrug and toxic compound extrusion (MATE) transporter involved in seed coat pigmentation. Two, one, and one full-length TT12 genes were isolated from B. napus, B. oleracea, and B. rapa, respectively, and Southern hybridization confirmed these gene numbers, implying loss of some of the triplicated TT12 genes in Brassica. BnTT12-1, BnTT12-2, BoTT12, and BrTT12 are 2,714, 3,062, 4,760, and 2,716 bp, with the longest mRNAs of 1,749, 1,711, 1,739, and 1,752 bp, respectively. All genes contained alternative transcriptional start and polyadenylation sites. BrTT12 and BoTT12 are the progenitors of BnTT12-1 and BnTT12-2, respectively, validating B. napus as an amphidiploid. All Brassica TT12 proteins displayed high levels of identity (>99%) to each other and to AtTT12 (>92%). Brassica TT12 genes resembled AtTT12 in such basic features as MatE/NorM CDs, subcellular localization, transmembrane helices, and phosphorylation sites. Plant TT12 orthologs differ from other MATE proteins by two specific motifs. Like AtTT12, all Brassica TT12 genes are most highly expressed in developing seeds. However, a range of organ specificity was observed with BnTT12 genes being less organ-specific. TT12 expression is absent in B. rapa yellow-seeded line 06K124, but not downregulated in B. oleracea yellow-seeded line 06K165. In B. napus yellow-seeded line L2, BnTT12-2 expression is absent, whereas BnTT12-1 is expressed normally. Among Brassica species, TT12 genes are differentially related to the yellow seed trait. The molecular basis for the yellow seed trait, in Brassica, and the theoretical and practical implications of the highly variable intron 1 of these TT12 genes are discussed.

  15. How To Measure Gravitational Aberration?

    NASA Astrophysics Data System (ADS)

    Krizek, M.; Solcova, A.

    2007-08-01

    In 1905, Henri Poincaré predicted the existence of gravitational waves and assumed that their speed c[g] would be that of the speed of light c. If the gravitational aberration would also have the same magnitude as the aberration of light, we would observe several paradoxical phenomena. For instance, the orbit of two bodies of equal mass would be unstable, since two attractive forces arise that are not in line and hence form a couple. This tends to increase the angular momentum, period, and total energy of the system. This can be modelled by a system of ordinary differential equations with delay. A big advantage of computer simulation is that we can easily perform many test for various possible values of the speed of gravity [1]. In [2], Carlip showed that gravitational aberration in general relativity is almost cancelled out by velocity-dependent interactions. This means that rays of sunlight are not parallel to the attractive gravitational force of the Sun, i.e., we do not see the Sun in the direction of its attractive force, but slightly shifted about an angle less than 20``. We show how the actual value of the gravitational aberration can be obtained by measurement of a single angle at a suitable time instant T corresponding to the perihelion of an elliptic orbit. We also derive an a priori error estimate that expresses how acurately T has to be determined to attain the gravitational aberration to a prescribed tolerance. [1] M. Křížek: Numerical experience with the finite speed of gravitational interaction, Math. Comput. Simulation 50 (1999), 237-245. [2] S. Carlip: Aberration and the speed of gravity, Phys. Lett. A 267 (2000), 81-87.

  16. Manipulation of spatiotemporal photon distribution via chromatic aberration.

    PubMed

    Li, Yuelin; Chemerisov, Sergey

    2008-09-01

    We demonstrate a spatiotemporal laser-pulse-shaping scheme that exploits the chromatic aberration in a dispersive lens. This normally harmful effect transforms the phase modulation into a beam-size modulation at the focal plane. In combination with the intricate diffraction effect via beam apodization, this method provides a spatiotemporal control of photon distribution with an accuracy of diffraction limit on a time scale of femtoseconds.

  17. Four-zone varifocus mirrors with adaptive control of primary and higher-order spherical aberration.

    PubMed

    Lukes, Sarah J; Downey, Ryan D; Kreitinger, Seth T; Dickensheets, David L

    2016-07-01

    Electrostatically actuated deformable mirrors with four concentric annular electrodes can exert independent control over defocus as well as primary, secondary, and tertiary spherical aberration. In this paper we use both numerical modeling and physical measurements to characterize recently developed deformable mirrors with respect to the amount of spherical aberration each can impart, and the dependence of that aberration control on the amount of defocus the mirror is providing. We find that a four-zone, 4 mm diameter mirror can generate surface shapes with arbitrary primary, secondary, and tertiary spherical aberration over ranges of ±0.4, ±0.2, and ±0.15  μm, respectively, referred to a non-normalized Zernike polynomial basis. We demonstrate the utility of this mirror for aberration-compensated focusing of a high NA optical system.

  18. Wave aberration function and its definition

    NASA Astrophysics Data System (ADS)

    Zverev, V. A.; Rytova, E. S.; Timoshchuk, I. N.

    2011-06-01

    A definition of a wave aberration as a phase shift upon composition of light waves in the image of a point is given using the concept of point eikonal. An expression that determines the total differential of a wave aberration function is obtained and the condition of its integrability is determined. The sequence of the wave aberration function definition at the known functions of the meridional and sagittal components of lateral aberration is presented.

  19. Using geometric algebra to study optical aberrations

    SciTech Connect

    Hanlon, J.; Ziock, H.

    1997-05-01

    This paper uses Geometric Algebra (GA) to study vector aberrations in optical systems with square and round pupils. GA is a new way to produce the classical optical aberration spot diagrams on the Gaussian image plane and surfaces near the Gaussian image plane. Spot diagrams of the third, fifth and seventh order aberrations for square and round pupils are developed to illustrate the theory.

  20. Phase Aberrations in Diffraction Microscopy

    SciTech Connect

    Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M

    2005-09-29

    In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.

  1. Pathophysiology of MDS: genomic aberrations.

    PubMed

    Ichikawa, Motoshi

    Myelodysplastic syndromes (MDS) are characterized by clonal proliferation of hematopoietic stem/progenitor cells and their apoptosis, and show a propensity to progress to acute myelogenous leukemia (AML). Although MDS are recognized as neoplastic diseases caused by genomic aberrations of hematopoietic cells, the details of the genetic abnormalities underlying disease development have not as yet been fully elucidated due to difficulties in analyzing chromosomal abnormalities. Recent advances in comprehensive analyses of disease genomes including whole-genome sequencing technologies have revealed the genomic abnormalities in MDS. Surprisingly, gene mutations were found in approximately 80-90% of cases with MDS, and the novel mutations discovered with these technologies included previously unknown, MDS-specific, mutations such as those of the genes in the RNA-splicing machinery. It is anticipated that these recent studies will shed new light on the pathophysiology of MDS due to genomic aberrations.

  2. Seidel aberrations of the Gabor superlens.

    PubMed

    Hamilton Shepard, R

    2014-02-10

    Equations are presented for the third-order Seidel aberrations of the Gabor superlens (GSL) as a function of microtelescope channel position within the aperture array. To reveal the origin and form of increasing aberration with channel height, Seidel coefficients are derived as a function of the accumulating pitch difference between the lens arrays and the aberrations present in the centered channel. Two- and three-element Gabor lenses are investigated and their aberrations are expressed as a function of first-order design parameters. The derived theory is then compared to a real ray trace simulation to demonstrate the accuracy of third-order aberration theory to predict GSL image quality.

  3. Neural compensation for the eye's optical aberrations.

    PubMed

    Artal, Pablo; Chen, Li; Fernández, Enrique J; Singer, Ben; Manzanera, Silvestre; Williams, David R

    2004-04-16

    A fundamental problem facing sensory systems is to recover useful information about the external world from signals that are corrupted by the sensory process itself. Retinal images in the human eye are affected by optical aberrations that cannot be corrected with ordinary spectacles or contact lenses, and the specific pattern of these aberrations is different in every eye. Though these aberrations always blur the retinal image, our subjective impression is that the visual world is sharp and clear, suggesting that the brain might compensate for their subjective influence. The recent introduction of adaptive optics to control the eye's aberrations now makes it possible to directly test this idea. If the brain compensates for the eye's aberrations, vision should be clearest with the eye's own aberrations rather than with unfamiliar ones. We asked subjects to view a stimulus through an adaptive optics system that either recreated their own aberrations or a rotated version of them. For all five subjects tested, the stimulus seen with the subject's own aberrations was always sharper than when seen through the rotated version. This supports the hypothesis that the neural visual system is adapted to the eye's aberrations, thereby removing somehow the effects of blur generated by the sensory apparatus from visual experience. This result could have important implications for methods to correct higher order aberrations with customized refractive surgery because some benefits of optimizing the correction optically might be undone by the nervous system's compensation for the old aberrations.

  4. Aberration

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (1) The apparent displacement of a star from its mean position on the celestial sphere due to the velocity of the Earth in its orbit around the Sun. The phenomenon was discovered in 1729 by James Bradley (1693-1762) who was, in fact, trying to measure stellar parallax. The displacement is caused by the combination of the velocity of the Earth and the velocity of light approaching from the source. ...

  5. Correlations between corneal and total wavefront aberrations

    NASA Astrophysics Data System (ADS)

    Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

    2002-06-01

    Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p < 0.05) between the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

  6. Determination of aberration center of Ronchigram for automated aberration correctors in scanning transmission electron microscopy.

    PubMed

    Sannomiya, Takumi; Sawada, Hidetaka; Nakamichi, Tomohiro; Hosokawa, Fumio; Nakamura, Yoshio; Tanishiro, Yasumasa; Takayanagi, Kunio

    2013-12-01

    A generic method to determine the aberration center is established, which can be utilized for aberration calculation and axis alignment for aberration corrected electron microscopes. In this method, decentering induced secondary aberrations from inherent primary aberrations are minimized to find the appropriate axis center. The fitness function to find the optimal decentering vector for the axis was defined as a sum of decentering induced secondary aberrations with properly distributed weight values according to the aberration order. Since the appropriate decentering vector is determined from the aberration values calculated at an arbitrary center axis, only one aberration measurement is in principle required to find the center, resulting in /very fast center search. This approach was tested for the Ronchigram based aberration calculation method for aberration corrected scanning transmission electron microscopy. Both in simulation and in experiments, the center search was confirmed to work well although the convergence to find the best axis becomes slower with larger primary aberrations. Such aberration center determination is expected to fully automatize the aberration correction procedures, which used to require pre-alignment of experienced users. This approach is also applicable to automated aperture positioning.

  7. Aberrations for Grazing Incidence Optics

    NASA Technical Reports Server (NTRS)

    Saha, Timo T.

    2008-01-01

    Large number of grazing incidence telescope configurations have been designed and studied. Wolte1 telescopes are commonly used in astronomical applications. Wolter telescopes consist of a paraboloidal primary mirror and a hyperboloidal or an ellipsoidal secondary mirror. There are 8 possible combinations of Wolter telescopes. Out of these possible designs only type 1 and type 2 telescopes are widely used. Type 1 telescope is typically used for x-ray applications and type 2 telescopes are used for EUV applications. Wolter-Schwarzshild (WS) telescopes offer improved image quality over a small field of view. The WS designs are stigmatic and free of third order coma and, therefore, the PSF is significantly better over a small field of view. Typically the image is more symmetric about its centroid. As for the Wolter telescopes there are 8 possible combinations of WS telescopes. These designs have not been widely used because the surface equations are complex parametric equations complicating the analysis and typically the resolution requirements are too low to take full advantage of the WS designs. There are several other design options. Most notable are wide field x-ray telescope designs. Polynomial designs were originally suggested by Burrows4 and hyperboloid-hyperboloid designs for solar physics applications were designed by Harvey5. No general aberration theory exists for grazing incidence telescopes that would cover all the design options. Several authors have studied the aberrations of grazing incidence telescopes. A comprehensive theory of Wolter type 1 and 2 telescopes has been developed. Later this theory was expanded to include all possible combinations of grazing incidence and also normal incidence paraboloid-hyperboloid and paraboloid-ellipsoid telescopes. In this article the aberration theory of Wolter type telescopes is briefly reviewed.

  8. [Aluminum induces chromosome aberrations in wheat root meristem cells].

    PubMed

    Bulanova, N V; Synzynys, B I; Koz'min, G V

    2001-12-01

    The yield and pattern of chromosome structure aberrations in wheat seedlings treated with aluminum nitrate and aluminum sulfate at various concentrations have been determined by the anaphase method. Aluminum has a genotoxic effect causing genome, chromatid, and chromosome aberrations in apical root meristem cells. The relationship between the total yield of structural mutations and the aluminum concentration follows a bell-shaped curve. The mutagenic activity of aluminum nitrate peaks at 10(-3) mg/ml, which is twice as high as the permissible concentration limit (PCL) of aluminum in potable water. The maximum of the mutagenic activity of aluminum sulfate is observed at 5 x 10(-4) mg/ml, i.e., one PCL. Tap water boiled for 2 h in an aluminum vessel has virtually no genotoxic effect on wheat cells.

  9. The misalignment induced aberrations of TMA telescopes.

    PubMed

    Thompson, Kevin P; Schmid, Tobias; Rolland, Jannick P

    2008-12-08

    The next major space-borne observatory, the James Webb Space Telescope, will be a 6.6M field-biased, obscured, three-mirror anastigmat (TMA). Over the used field of view, the performance of TMA telescopes is dominated by 3(rd) order misalignment aberrations. Here it is shown that two dominant 3(rd) order misalignment aberrations arise for any TMA telescope. One aberration, field constant 3(rd) order coma is a well known misalignment aberration commonly seen in two-mirror Ritchey Chretien telescopes. The second aberration, field-asymmetric, field-linear, 3(rd) order astigmatism is a new and unique image orientation dependence with field derived here for the first time using nodal aberration theory.

  10. Phase and birefringence aberration correction

    DOEpatents

    Bowers, Mark; Hankla, Allen

    1996-01-01

    A Brillouin enhanced four wave mixing phase conjugate mirror corrects phase aberrations of a coherent electromagnetic beam and birefringence induced upon that beam. The stimulated Brillouin scattering (SBS) phase conjugation technique is augmented to include Brillouin enhanced four wave mixing (BEFWM). A seed beam is generated by a main oscillator which arrives at the phase conjugate cell before the signal beams in order to initiate the Brillouin effect. The signal beam which is being amplified through the amplifier chain is split into two perpendicularly polarized beams. One of the two beams is chosen to be the same polarization as some component of the seed beam, the other orthogonal to the first. The polarization of the orthogonal beam is then rotated 90.degree. such that it is parallel to the other signal beam. The three beams are then focused into cell containing a medium capable of Brillouin excitation. The two signal beams are focused such that they cross the seed beam path before their respective beam waists in order to achieve BEFWM or the two signal beams are focused to a point or points contained within the focused cone angle of the seed beam to achieve seeded SBS, and thus negate the effects of all birefringent and material aberrations in the system.

  11. Phase and birefringence aberration correction

    DOEpatents

    Bowers, M.; Hankla, A.

    1996-07-09

    A Brillouin enhanced four wave mixing phase conjugate mirror corrects phase aberrations of a coherent electromagnetic beam and birefringence induced upon that beam. The stimulated Brillouin scattering (SBS) phase conjugation technique is augmented to include Brillouin enhanced four wave mixing (BEFWM). A seed beam is generated by a main oscillator which arrives at the phase conjugate cell before the signal beams in order to initiate the Brillouin effect. The signal beam which is being amplified through the amplifier chain is split into two perpendicularly polarized beams. One of the two beams is chosen to be the same polarization as some component of the seed beam, the other orthogonal to the first. The polarization of the orthogonal beam is then rotated 90{degree} such that it is parallel to the other signal beam. The three beams are then focused into cell containing a medium capable of Brillouin excitation. The two signal beams are focused such that they cross the seed beam path before their respective beam waists in order to achieve BEFWM or the two signal beams are focused to a point or points contained within the focused cone angle of the seed beam to achieve seeded SBS, and thus negate the effects of all birefringent and material aberrations in the system. 5 figs.

  12. Aberrations of ellipsoidal reflectors for unit magnification.

    PubMed

    Mielenz, K D

    1974-12-01

    Ellipsoidal reflectors are useful for the 1:1 imaging of small objects without spherical and chromatic aberration. The magnitude of the off-axis aberrations of such reflectors is computed by application of Fermat's principle to the Hamiltonian point characteristic. The limiting form of the mirror aperture for which these aberrations do not exceed a set tolerance is an ellipse whose semiaxes depend on object size and angle of incidence.

  13. Chromatic aberration measurement for transmission interferometric testing.

    PubMed

    Seong, Kibyung; Greivenkamp, John E

    2008-12-10

    A method of chromatic aberration measurement is described based on the transmitted wavefront of an optical element obtained from a Mach-Zehnder interferometer. The chromatic aberration is derived from transmitted wavefronts measured at five different wavelengths. Reverse ray tracing is used to remove induced aberrations associated with the interferometer from the measurement. In the interferometer, the wavefront transmitted through the sample is tested against a plano reference, allowing for the absolute determination of the wavefront radius of curvature. The chromatic aberrations of a singlet and a doublet have been measured.

  14. Monochromatic ocular wave aberrations in young monkeys

    PubMed Central

    Ramamirtham, Ramkumar; Kee, Chea-su; Hung, Li-Fang; Qiao-Grider, Ying; Roorda, Austin; Smith, Earl L.

    2006-01-01

    High-order monochromatic aberrations could potentially influence vision-dependent refractive development in a variety of ways. As a first step in understanding the effects of wave aberration on refractive development, we characterized the maturational changes that take place in the high-order aberrations of infant rhesus monkey eyes. Specifically, we compared the monochromatic wave aberrations of infant and adolescent animals and measured the longitudinal changes in the high-order aberrations of infant monkeys during the early period when emmetropization takes place. Our main findings were that (1) adolescent monkey eyes have excellent optical quality, exhibiting total RMS errors that were slightly better than those for adult human eyes that have the same numerical aperture and (2) shortly after birth, infant rhesus monkeys exhibited relatively larger magnitudes of high-order aberrations predominately spherical aberration, coma, and trefoil, which decreased rapidly to assume adolescent values by about 200 days of age. The results demonstrate that rhesus monkey eyes are a good model for studying the contribution of individual ocular components to the eye’s overall aberration structure, the mechanisms responsible for the improvements in optical quality that occur during early ocular development, and the effects of high-order aberrations on ocular growth and emmetropization. PMID:16750549

  15. Analysis of nodal aberration properties in off-axis freeform system design.

    PubMed

    Shi, Haodong; Jiang, Huilin; Zhang, Xin; Wang, Chao; Liu, Tao

    2016-08-20

    Freeform surfaces have the advantage of balancing off-axis aberration. In this paper, based on the framework of nodal aberration theory (NAT) applied to the coaxial system, the third-order astigmatism and coma wave aberration expressions of an off-axis system with Zernike polynomial surfaces are derived. The relationship between the off-axis and surface shape acting on the nodal distributions is revealed. The nodal aberration properties of the off-axis freeform system are analyzed and validated by using full-field displays (FFDs). It has been demonstrated that adding Zernike terms, up to nine, to the off-axis system modifies the nodal locations, but the field dependence of the third-order aberration does not change. On this basis, an off-axis two-mirror freeform system with 500 mm effective focal length (EFL) and 300 mm entrance pupil diameter (EPD) working in long-wave infrared is designed. The field constant aberrations induced by surface tilting are corrected by selecting specific Zernike terms. The design results show that the nodes of third-order astigmatism and coma move back into the field of view (FOV). The modulation transfer function (MTF) curves are above 0.4 at 20 line pairs per millimeter (lp/mm) which meets the infrared reconnaissance requirement. This work provides essential insight and guidance for aberration correction in off-axis freeform system design.

  16. Aberration estimation from single point image in a simulated adaptive optics system.

    PubMed

    Grisan, Enrico; Frassetto, Fabio; Da Deppo, Vania; Naletto, Giampiero; Ruggeri, Alfredo

    2005-01-01

    Adaptive optics has been recently applied for the development of ophthalmic devices, with the main objective of obtaining higher resolution images for diagnostic purposes or ideally correcting high-order eye aberrations. The core of every adaptive optics systems is an optical device that is able to modify the wavefront shape of the light entering a system: once the shape of the incoming wavefront has been estimated, by means of this device it is possible to correct the aberrations introduced along the optical path. The aim of this paper is to demonstrate the feasibility, although in a simulated system, of estimating and correcting the wavefront shape simply by means of an iterative software analysis of a single point source image, thus avoiding expensive wavefront sensors or the burdensome computation of the PSF of the optical system. To test the proposed algorithm, a simple optical system has been simulated with a ray-tracing software and a program to estimate the Zernike coefficients of the simulated aberration from the analysis of the source image has been developed. Numerical indexes were used to evaluate the capability of the software of correctly estimating the Zernike coefficients. Even if only defocus, astigmatism and coma were considered, the very satisfactory results obtained confirm the soundness of this new approach and encourage further work in this direction, in order to develop a system able to estimate also spherical aberration, tilt and field curvature. An implementation of this aberration estimation in a real AO system is also currently in progress.

  17. Learning Disorders and Sex Chromosome Aberrations.

    ERIC Educational Resources Information Center

    Hier, D. B.; And Others

    1980-01-01

    In a prospective study of 20 adult dyslexic men, no sex chromosome aberrations were detected. A retrospective study of 89 Ss with known sex chromosome aberrations revealed 20 of them to be mentally retarded. Among the 69 Ss of normal intelligence, learning, speech, and attention disorders were frequent. (Author/DLS)

  18. Aberrant "Barbed-Wire" Nuclear Projections of Neutrophils in Trisomy 18 (Edwards Syndrome).

    PubMed

    Kahwash, Basil M; Nowacki, Nicholas B; Kahwash, Samir B

    2015-01-01

    We discuss the significance of neutrophils with increased, aberrant nuclear projections mimicking "barbed-wire" in a newborn child with trisomy 18 (T18). Increased, aberrant nuclear projections have been previously reported in trisomy of the D group of chromosomes (chromosomes 13, 14, and 15), and we report similar findings in a patient with T18. The peripheral blood smear showed relative neutrophilia with the majority (37%) of neutrophils showing two or more thin, rod-shaped or spike-shaped, and often pedunculated aberrant nuclear projections. The number of projections ranged from 2 to 6 per cell, averaged 2 per affected neutrophil, and ranged in length from 0.22 μm to 0.83 μm. This case confirms that the morphologic finding described is not restricted to trisomy of one of the chromosomes in group D, as implied in the literature.

  19. The TRANSPARENT TESTA16 Locus Encodes the ARABIDOPSIS BSISTER MADS Domain Protein and Is Required for Proper Development and Pigmentation of the Seed Coat

    PubMed Central

    Nesi, Nathalie; Debeaujon, Isabelle; Jond, Clarisse; Stewart, Amanda J.; Jenkins, Gareth I.; Caboche, Michel; Lepiniec, Loïc

    2002-01-01

    Screening for seed pigmentation phenotypes in Arabidopsis led to the isolation of three allelic yellow-seeded mutants, which defined the novel TRANSPARENT TESTA16 (TT16) locus. Cloning of TT16 was performed by T-DNA tagging and confirmed by genetic complementation and sequencing of two mutant alleles. TT16 encodes the ARABIDOPSIS BSISTER (ABS) MADS domain protein. ABS belongs to the recently identified “B-sister” (BS) clade, which contains genes of unknown function that are expressed mainly in female organs. Phylogenetic analyses using a maximum parsimony approach confirmed that TT16/ABS and related proteins form a monophyletic group. TT16/ABS was expressed mainly in the ovule, as are the other members of the BS clade. TT16/ABS is necessary for BANYULS expression and proanthocyanidin accumulation in the endothelium of the seed coat, with the exception of the chalazal-micropylar area. In addition, mutant phenotype and ectopic expression analyses suggested that TT16/ABS also is involved in the specification of endothelial cells. Nevertheless, TT16/ABS apparently is not required for proper ovule function. We report the functional characterization of a member of the BS MADS box gene subfamily, demonstrating its involvement in endothelial cell specification as well as in the increasingly complex genetic control of flavonoid biosynthesis in the Arabidopsis seed coat. PMID:12368498

  20. The Effect of TRANSPARENT TESTA2 on Seed Fatty Acid Biosynthesis and Tolerance to Environmental Stresses during Young Seedling Establishment in Arabidopsis1[W][OA

    PubMed Central

    Chen, Mingxun; Wang, Zhong; Zhu, Yana; Li, Zhilan; Hussain, Nazim; Xuan, Lijie; Guo, Wanli; Zhang, Guoping; Jiang, Lixi

    2012-01-01

    In plants, fatty acids (FAs) and FA-derived complex lipids are major carbon and energy reserves in seeds. They are essential components of cellular membranes and cellular signal or hormone molecules. Although TRANSPARENT TESTA2 (TT2) is well studied for its function in regulating proanthocyanidin biosynthesis in the seed coat, little attention has been given to its role in affecting seed FA accumulation and tolerance to environmental stresses. We demonstrate that the tt2 mutation remarkably increased the seed FA content, decreased seed weight, and altered the FA composition. The increase in FA content in the tt2 seeds was due to the relative decrease of seed coat proportion as well as the more efficient FA synthesis in the tt2 embryo. Microarray analysis revealed that tt2 mutation up-regulated a group of genes critical to FA biosynthesis and embryonic development. The mutation also altered the gene expressions that respond to stress. The microarray analysis discovered that the increase in FA accumulation of the tt2 seeds were accompanied by the significant up-regulation of FUSCA3, a transcriptional factor for embryonic development and FATTY ACID ELONGASE1, which catalyzes the elongation of FA chains. Moreover, lower seed protein accumulation during seed maturation also contributed to the increased seed FA accumulation in tt2 mutants. This study advances the understanding of the TT2 gene in seed FA accumulation and abiotic stresses during seed germination and seedling establishment. PMID:22879396

  1. Iteration of ultrasound aberration correction methods

    NASA Astrophysics Data System (ADS)

    Maasoey, Svein-Erik; Angelsen, Bjoern; Varslot, Trond

    2004-05-01

    Aberration in ultrasound medical imaging is usually modeled by time-delay and amplitude variations concentrated on the transmitting/receiving array. This filter process is here denoted a TDA filter. The TDA filter is an approximation to the physical aberration process, which occurs over an extended part of the human body wall. Estimation of the TDA filter, and performing correction on transmit and receive, has proven difficult. It has yet to be shown that this method works adequately for severe aberration. Estimation of the TDA filter can be iterated by retransmitting a corrected signal and re-estimate until a convergence criterion is fulfilled (adaptive imaging). Two methods for estimating time-delay and amplitude variations in receive signals from random scatterers have been developed. One method correlates each element signal with a reference signal. The other method use eigenvalue decomposition of the receive cross-spectrum matrix, based upon a receive energy-maximizing criterion. Simulations of iterating aberration correction with a TDA filter have been investigated to study its convergence properties. A weak and strong human-body wall model generated aberration. Both emulated the human abdominal wall. Results after iteration improve aberration correction substantially, and both estimation methods converge, even for the case of strong aberration.

  2. Focusing Diffraction Grating Element with Aberration Control

    NASA Technical Reports Server (NTRS)

    Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christoph M.

    2010-01-01

    Diffraction gratings are optical components with regular patterns of grooves, which angularly disperse incoming light by wavelength in a single plane, called dispersion plane. Traditional gratings on flat substrates do not perform wavefront transformation in the plane perpendicular to the dispersion plane. The device proposed here exhibits regular diffraction grating behavior, dispersing light. In addition, it performs wavelength transformation (focusing or defocusing) of diffracted light in a direction perpendicular to the dispersion plane (called sagittal plane). The device is composed of a diffraction grating with the grooves in the form of equidistant arcs. It may be formed by defining a single arc or an arc approximation, then translating it along a certain direction by a distance equal to a multiple of a fixed distance ("grating period") to obtain other groove positions. Such groove layout is nearly impossible to obtain using traditional ruling methods, such as mechanical ruling or holographic scribing, but is trivial for lithographically scribed gratings. Lithographic scribing is the newly developed method first commercially introduced by LightSmyth Technologies, which produces gratings with the highest performance and arbitrary groove shape/spacing for advanced aberration control. Unlike other types of focusing gratings, the grating is formed on a flat substrate. In a plane perpendicular to the substrate and parallel to the translation direction, the period of the grating and, therefore, the projection of its k-vector onto the plane is the same for any location on the grating surface. In that plane, no waveform transformation by the grating k-vector occurs, except of simple redirection.

  3. Polarization aberrations of crossed folding mirrors

    NASA Astrophysics Data System (ADS)

    Crandall, David G.; Chipman, Russell A.

    1995-08-01

    Polarization aberrations due to varying polarization state across the field of view (FOV) are investigated for crossed folding mirrors. We define crossed mirrors as oriented in space such that s-polarized light incident on the first mirror is p-polarized at the second mirror. This completely compensates for polarization state changes at one point in the field of view. The resulting polarization aberrations are explored across the FOV using the example of aluminum mirrors overcoated with a 12 layer, highly reflective, dielectric stack. The polarization aberration is very low along a band across the field of view. For arbitrary points in the FOV, the retardance and diattenuation are slightly elliptical.

  4. The construction of individual eye model based on eye's wavefront aberration measurement

    NASA Astrophysics Data System (ADS)

    Wang, Zhao-Qi; Guo, Huan-Qing

    2005-08-01

    Based on the widely used Gullstrand-Le Grand eye model, the individual human eye model has been established here, which has individual corneal data, anterior chamber depth and the eyeball depth. Furthermore the foremost thing is that the wavefront aberration calculated from the individual eye model is equal to the eye's wavefront aberration measured with the Hartmann-shack wavefront sensor. There were four main steps to build the model. Firstly, the corneal topography instrument was used to measure the corneal surfaces and depth. And in order to input cornea into the optical model, high order aspheric surface-Zernike Fringe Sag surface was chosen to fit the corneal surfaces. Secondly, the Hartmann-shack wavefront sensor, which can offer the Zernike polynomials to describe the wavefront aberration, was built to measure the wavefront aberration of the eye. Thirdly, the eye's axial lengths among every part were measured with A-ultrasonic technology. Then the data were input into the optical design software -ZEMAX and the crystalline lens's shapes were optimized with the aberration as the merit function. The individual eye model, which has the same wavefront aberrations with the real eye, is established.

  5. Sensing Phase Aberrations behind Lyot Coronagraphs

    NASA Astrophysics Data System (ADS)

    Sivaramakrishnan, Anand; Soummer, Rémi; Pueyo, Laurent; Wallace, J. Kent; Shao, Michael

    2008-11-01

    Direct detection of young extrasolar planets orbiting nearby stars can be accomplished from the ground with extreme adaptive optics and coronagraphy in the near-infrared, as long as this combination can provide an image with a dynamic range of 107 after the data are processed. Slowly varying speckles due to residual phase aberrations that are not measured by the primary wave-front sensor are the primary obstacle to achieving such a dynamic range. In particular, non-common optical path aberrations occurring between the wave-front sensor and the coronagraphic occulting spot degrade performance the most. We analyze the passage of both low and high spatial frequency phase ripples, as well as low-order Zernike aberrations, through an apodized pupil Lyot coronagraph in order to demonstrate the way coronagraphic filtering affects various aberrations. We derive the coronagraphically induced cutoff frequency of the filtering and estimate coronagraphic contrast losses due to low-order Zernike aberrations: tilt, astigmatism, defocus, coma, and spherical aberration. Such slowly varying path errors can be measured behind a coronagraph and corrected by a slowly updated optical path delay precompensation or offset asserted on the wave front by the adaptive optics (AO) system. We suggest ways of measuring and correcting all but the lowest spatial frequency aberrations using Lyot plane wave-front data, in spite of the complex interaction between the coronagraph and those mid-spatial frequency aberrations that cause image plane speckles near the coronagraphic focal plane mask occulter's edge. This investigation provides guidance for next-generation coronagraphic instruments currently under construction.

  6. Prediction of Visual Acuity from Wavefront Aberrations

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B. (Inventor); Ahumada, Albert J. (Inventor)

    2013-01-01

    A method for generating a visual acuity metric, based on wavefront aberrations (WFAs), associated with a test subject and representing classes of imperfections, such as defocus, astigmatism, coma and spherical aberrations, of the subject's visual system. The metric allows choices of different image template, can predict acuity for different target probabilities, can incorporate different and possibly subject-specific neural transfer functions, can predict acuity for different subject templates, and incorporates a model of the optotype identification task.

  7. Chromosome aberrations in decondensed sperm DNA

    SciTech Connect

    Preston, R.J.

    1982-01-01

    Factors that could influence the chromosomal aberration frequency observed at first cleavage following in vivo exposure of germ cells to chemical mutagens are discussed. The techniques of chromosome aberration analysis following sperm DNA condensation by in vitro fertilization or fusion seem to be viable research areas for providing information of human germ cell exposures. However, the potential sensitivity of the assay needs to be better understood, and factors that can influence this sensitivity require a great deal of further study using animal models.

  8. Image aberrations in optical three-dimensional measurement systems with fringe projection.

    PubMed

    Brakhage, Peter; Notni, Gunther; Kowarschik, Richard

    2004-06-01

    In optical shape measurement systems, systematic errors appear as a result of imaging aberrations of the lens assemblies in the cameras and projectors. A mathematical description of this effect is intended to correct the whole measurement area with a few independent coefficients. We apply the ideas of photogrammetry to one- and two-dimensional fringe projection techniques. We also introduce some new terms for close-range applications and telecentric objectives. Further, an algorithm for distance-dependent corrections is introduced. Also, we describe a new method with which to determine coefficients of aberration with an optimization-based method.

  9. The three-dimensional point spread function of aberration-corrected scanning transmission electron microscopy.

    PubMed

    Lupini, Andrew R; de Jonge, Niels

    2011-10-01

    Aberration correction reduces the depth of field in scanning transmission electron microscopy (STEM) and thus allows three-dimensional (3D) imaging by depth sectioning. This imaging mode offers the potential for sub-Ångstrom lateral resolution and nanometer-scale depth sensitivity. For biological samples, which may be many microns across and where high lateral resolution may not always be needed, optimizing the depth resolution even at the expense of lateral resolution may be desired, aiming to image through thick specimens. Although there has been extensive work examining and optimizing the probe formation in two dimensions, there is less known about the probe shape along the optical axis. Here the probe shape is examined in three dimensions in an attempt to better understand the depth resolution in this mode. Examples are presented of how aberrations change the probe shape in three dimensions, and it is found that off-axial aberrations may need to be considered for focal series of large areas. It is shown that oversized or annular apertures theoretically improve the vertical resolution for 3D imaging of nanoparticles. When imaging nanoparticles of several nanometer size, regular STEM can thereby be optimized such that the vertical full-width at half-maximum approaches that of the aberration-corrected STEM with a standard aperture.

  10. Pulse compressor with aberration correction

    SciTech Connect

    Mankos, Marian

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  11. Dynamic aberration correction for conformal optics using model-based wavefront sensorless adaptive optics

    NASA Astrophysics Data System (ADS)

    Han, Xinli; Dong, Bing; Li, Yan; Wang, Rui; Hu, Bin

    2016-10-01

    For missiles and airplanes with high Mach number, traditional spherical or flat window can cause a lot of air drag. Conformal window that follow the general contour of surrounding surface can substantially decrease air drag and extend operational range. However, the local shape of conformal window changes across the Field Of Regard (FOR), leading to time-varying FOR-dependent wavefront aberration and degraded image. So the correction of dynamic aberration is necessary. In this paper, model-based Wavefront Sensorless Adaptive Optics (WSAO) algorithm is investigated both by simulation and experiment for central-obscured pupil. The algorithm is proved to be effective and the correction accuracy of using DM modes is higher than Lukosz modes. For dynamic aberration in our system, the SR can be better than 0.8 when the change of looking angle is less than 2° after t seconds which is the time delay of the control system.

  12. Harmonic imaging with fresnel beamforming in the presence of phase aberration.

    PubMed

    Nguyen, Man Minh; Shin, Junseob; Yen, Jesse

    2014-10-01

    Fresnel beamforming is a beamforming method with a delay profile similar in shape to a physical Fresnel lens. The advantage of Fresnel beamforming is the reduced channel count, which consists of four to eight transmit and two analog-to-digital receive channels. Fresnel beamforming was found to perform comparably to conventional delay-and-sum beamforming. However, the performance of Fresnel beamforming is highly dependent on focal errors. These focal errors result in high side-lobe levels and further reduce the performance of Fresnel beamforming in the presence of phase aberration. With the advantages of lower side-lobe levels and suppression of aberration effects, harmonic imaging offers an effective solution to the limitations of Fresnel beamforming. We describe the implementation of tissue harmonic imaging and pulse inversion harmonic imaging in Fresnel beamforming, followed by dual apodization with cross-correlation, to improve image quality. Compared with conventional delay-and-sum beamforming, experimental results indicated contrast-to-noise ratio improvements of 10%, 49% and 264% for Fresnel beamforming using tissue harmonic imaging in the cases of no aberrator, 5-mm pork aberrator and 12-mm pork aberrator, respectively. These improvements were 22%, 57% and 352% for Fresnel beamforming using pulse inversion harmonic imaging. Moreover, dual apodization with cross-correlation was found to further improve the contrast-to-noise ratios in all cases. Harmonic imaging was also found to narrow the lateral beamwidth and shorten the axial pulse length by at least 25% and 21%, respectively, for Fresnel beamforming at different aberration levels. These results suggest the effectiveness of harmonic imaging in improving image quality for Fresnel beamforming, especially in the presence of phase aberration. Even though this combination of Fresnel beamforming and harmonic imaging does not outperform delay-and-sum beamforming combined with harmonic imaging, it provides the

  13. Aberration corrected Lorentz scanning transmission electron microscopy.

    PubMed

    McVitie, S; McGrouther, D; McFadzean, S; MacLaren, D A; O'Shea, K J; Benitez, M J

    2015-05-01

    We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale.

  14. Chromosome aberration test for hydroxyapatite in sheep.

    PubMed

    Kannan, T P; Nik Ahmad Shah, N L; Azlina, A; Samsudin, A R; Narazah, M Y; Salleh, Ma'arof

    2004-05-01

    The present study is aimed at finding the mutagenicity and cytotoxicity of dense form of synthetic hydroxyapatite (Source: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia) in the blood of sheep. The biomaterial was implanted in the tibia of Malin, an indigenous sheep breed of Malaysia. Blood was collected from the sheep before implantation of the biomaterial, cultured and a karyological study was made. Six weeks after implantation, blood was collected from the same animal, cultured and screened for chromosome aberrations. The mitotic indices and karyological analysis indicated that the implantation of synthetic hydroxyapatite (dense form) did not produce any cytotoxicity or chromosome aberrations in the blood of sheep.

  15. Misalignment induced aberration off-axis optical system

    NASA Astrophysics Data System (ADS)

    Pang, Zhihai; Fan, Xuewu; Ma, Zhen; Zou, Gangyi

    2016-10-01

    Through introducing transformed pupil vector and shifted center of aberration fields vector into the nodal aberration expansions of an axially symmetric optical system, the aberration expression in third order of an off-axis optical system and misaligned off-axis optical system are detailed. Nodal aberration characteristics of misaligned off-axis optical system are revealed only by analyzing the pupil decentration vector, aberration fields shifted vector and the aberration coefficients of the axially symmetric optical system. Actually, it is well demonstrated that the 3rd spherical aberration, 3rd coma, 3rd astigmatism in a misalignment off-axis system are comparable to the aberrations in a misalignment axially symmetric system. Otherwise it will not only induced constant 3rd spherical aberration but also constant 3rd coma and 3rd astigmatism over the field of view, when aligned an off-axis optical system elements with error axial spacing.

  16. Aberrations of diffracted wave fields. II. Diffraction gratings.

    PubMed

    Mahajan, V N

    2000-12-01

    The Rayleigh-Sommerfeld theory is applied to diffraction of a spherical wave by a grating. The grating equation is obtained from the aberration-free diffraction pattern, and its aberrations are shown to be the same as the conventional aberrations obtained by using Fermat's principle. These aberrations are shown to be not associated with the diffraction process. Moreover, it is shown that the irradiance distribution of a certain diffraction order is the Fraunhofer diffraction pattern of the grating aperture as a whole aberrated by the aberration of that order.

  17. Cosmological parameter estimation: impact of CMB aberration

    SciTech Connect

    Catena, Riccardo; Notari, Alessio E-mail: notari@ffn.ub.es

    2013-04-01

    The peculiar motion of an observer with respect to the CMB rest frame induces an apparent deflection of the observed CMB photons, i.e. aberration, and a shift in their frequency, i.e. Doppler effect. Both effects distort the temperature multipoles a{sub lm}'s via a mixing matrix at any l. The common lore when performing a CMB based cosmological parameter estimation is to consider that Doppler affects only the l = 1 multipole, and neglect any other corrections. In this paper we reconsider the validity of this assumption, showing that it is actually not robust when sky cuts are included to model CMB foreground contaminations. Assuming a simple fiducial cosmological model with five parameters, we simulated CMB temperature maps of the sky in a WMAP-like and in a Planck-like experiment and added aberration and Doppler effects to the maps. We then analyzed with a MCMC in a Bayesian framework the maps with and without aberration and Doppler effects in order to assess the ability of reconstructing the parameters of the fiducial model. We find that, depending on the specific realization of the simulated data, the parameters can be biased up to one standard deviation for WMAP and almost two standard deviations for Planck. Therefore we conclude that in general it is not a solid assumption to neglect aberration in a CMB based cosmological parameter estimation.

  18. Anti-forensics of chromatic aberration

    NASA Astrophysics Data System (ADS)

    Mayer, Owen; Stamm, Matthew C.

    2015-03-01

    Over the past decade, a number of information forensic techniques have been developed to identify digital image manipulation and falsification. Recent research has shown, however, that an intelligent forger can use anti-forensic countermeasures to disguise their forgeries. In this paper, an anti-forensic technique is proposed to falsify the lateral chromatic aberration present in a digital image. Lateral chromatic aberration corresponds to the relative contraction or expansion between an image's color channels that occurs due to a lens's inability to focus all wavelengths of light on the same point. Previous work has used localized inconsistencies in an image's chromatic aberration to expose cut-and-paste image forgeries. The anti-forensic technique presented in this paper operates by estimating the expected lateral chromatic aberration at an image location, then removing deviations from this estimate caused by tampering or falsification. Experimental results are presented that demonstrate that our anti-forensic technique can be used to effectively disguise evidence of an image forgery.

  19. Aberration features in directional dark matter detection

    SciTech Connect

    Bozorgnia, Nassim; Gelmini, Graciela B.; Gondolo, Paolo E-mail: gelmini@physics.ucla.edu

    2012-08-01

    The motion of the Earth around the Sun causes an annual change in the magnitude and direction of the arrival velocity of dark matter particles on Earth, in a way analogous to aberration of stellar light. In directional detectors, aberration of weakly interacting massive particles (WIMPs) modulates the pattern of nuclear recoil directions in a way that depends on the orbital velocity of the Earth and the local galactic distribution of WIMP velocities. Knowing the former, WIMP aberration can give information on the latter, besides being a curious way of confirming the revolution of the Earth and the extraterrestrial provenance of WIMPs. While observing the full aberration pattern requires extremely large exposures, we claim that the annual variation of the mean recoil direction or of the event counts over specific solid angles may be detectable with moderately large exposures. For example, integrated counts over Galactic hemispheres separated by planes perpendicular to Earth's orbit would modulate annually, resulting in Galactic Hemisphere Annual Modulations (GHAM) with amplitudes larger than the usual non-directional annual modulation.

  20. Functional Analysis and Treatment of Aberrant Behavior.

    ERIC Educational Resources Information Center

    Mace, F. Charles; And Others

    1991-01-01

    This article reviews general classes of variables which help to maintain aberrant behavior including attention seeking, sensory and perceptual consequences, and access to materials or activities. Suggestions for a methodology providing a comprehensive functional analysis are offered which include descriptive analysis, hypothesis forming,…

  1. The Extent of Mismeasurement for Aberrant Examinees

    ERIC Educational Resources Information Center

    Petridou, Alexandra; Williams, Julian

    2010-01-01

    The person-fit literature assumes that aberrant response patterns could be a sign of person mismeasurement, but this assumption has rarely, if ever, been empirically investigated before. We explore the validity of test responses and measures of 10-year-old examinees whose response patterns on a commercial standardized paper-and-pencil mathematics…

  2. Assessing the construct validity of aberrant salience.

    PubMed

    Schmidt, Kristin; Roiser, Jonathan P

    2009-01-01

    We sought to validate the psychometric properties of a recently developed paradigm that aims to measure salience attribution processes proposed to contribute to positive psychotic symptoms, the Salience Attribution Test (SAT). The "aberrant salience" measure from the SAT showed good face validity in previous results, with elevated scores both in high-schizotypy individuals, and in patients with schizophrenia suffering from delusions. Exploring the construct validity of salience attribution variables derived from the SAT is important, since other factors, including latent inhibition/learned irrelevance (LIrr), attention, probabilistic reward learning, sensitivity to probability, general cognitive ability and working memory could influence these measures. Fifty healthy participants completed schizotypy scales, the SAT, a LIrr task, and a number of other cognitive tasks tapping into potentially confounding processes. Behavioural measures of interest from each task were entered into a principal components analysis, which yielded a five-factor structure accounting for approximately 75% of the variance in behaviour. Implicit aberrant salience was found to load onto its own factor, which was associated with elevated "Introvertive Anhedonia" schizotypy, replicating our previous finding. LIrr loaded onto a separate factor, which also included implicit adaptive salience, but was not associated with schizotypy. Explicit adaptive and aberrant salience, along with a measure of probabilistic learning, loaded onto a further factor, though this also did not correlate with schizotypy. These results suggest that the measures of LIrr and implicit adaptive salience might be based on similar underlying processes, which are dissociable both from implicit aberrant salience and explicit measures of salience.

  3. Automatic low-order aberration correction based on geometry optics: simulations

    NASA Astrophysics Data System (ADS)

    Yu, Xin; Dong, Lizhi; Liu, Yong; Yang, Ping; Tang, Guomao; Xu, Bing

    2016-10-01

    The slab laser is a promising architecture to achieve high beam quality and high power. By propagating the laser beams in zigzag geometries, the temperature gradient in the gain medium can be well averaged, and the beam quality in this direction can be excellent. However, the temperature gradient in the non-zigzag direction is not compensated, resulting in aberrations in this direction which lead to poorer beam quality. Among the overall aberrations, the main contributors are two low-order aberrations: astigmatism and defocus. These aberrations will magnify beam divergence angle and degrade beam quality. If the beam divergence angles in both directions are almost zero, the astigmatism and defocus are well corrected. Besides, the output beams of slab lasers are generally in a rectangular aperture with high aspect ratio (normally 1:10), which need to be reshaped into square in many applications. In this paper, a new method is proposed to correct low-order aberrations and reshape the beams of slab lasers. Three lenses are adapted, one is a spherical lens and the others are cylindrical lenses. These lenses work as a beam shaping system, which converts the beam from rectangular into square and the low-order aberrations are compensated simultaneously. Two wavefront sensors are used to detect input and output beam parameters. The initial size of the beam is 4mm×20mm, and peak to valley (PV) value of the wavefront is several tens of microns. Simulation results show that after correction, the dimension becomes 40mm×40mm, and peak to valley (PV) value of the wavefront is less than 1microns.

  4. Accommodative lag and fluctuations when optical aberrations are manipulated.

    PubMed

    Gambra, Enrique; Sawides, Lucie; Dorronsoro, Carlos; Marcos, Susana

    2009-06-09

    We evaluated the accommodative response to a stimulus moving from 0 to 6 D following a staircase function under natural, corrected, and induced optical aberrations, using an adaptive-optics (AO) electromagnetic deformable mirror. The accommodative response of the eye (through the mirror) and the change of aberrations were measured on 5 subjects using a Hartmann-Shack wavefront sensor operating at 12.8 Hz. Five conditions were tested: (1) natural aberrations, (2) AO correction of the unaccommodated state and induction (over 6-mm pupils) of (3) +1 microm and (4) -1 microm of spherical aberration and (5) -2 microm of vertical coma. Four subjects showed a better accommodative response with AO correction than with their natural aberrations. The induction of negative spherical aberration also produced a better accommodative response in the same subjects. Accommodative lag increased in all subjects when positive spherical aberration and coma were induced. Fluctuations of the accommodative response (computed during each 1-D period of steady accommodation) increased with accommodative response when high-order aberrations were induced. The largest fluctuations occurred for induced negative spherical aberration and the smallest for natural and corrected aberrations. The study demonstrates that aberrations influence accommodative lag and fluctuations of accommodation and that correcting aberrations improves rather than compromises the accommodative response.

  5. Effects of interactions among wave aberrations on optical image quality.

    PubMed

    McLellan, J S; Prieto, P M; Marcos, S; Burns, S A

    2006-09-01

    Wave aberrations degrade the optical quality of the eye relative to the diffraction limit, but there are situations in which having slightly aberrated optics can provide some relative visual benefits. This fact led us to consider whether interactions among aberrations in the eye's wavefront produce an advantage for image quality relative to wavefronts with randomized combinations of aberrations with the same total RMS error. Total ocular wave aberrations from two experimental groups and corneal wave aberrations from one group were measured and expressed as Zernike polynomial expansions through the seventh-order. In a series of Monte Carlo simulations, modulation transfer functions (MTFs) for the measured wave aberrations were compared to distributions of artificial MTFs for wavefronts created by randomizing the sign or orientation of the aberrations, while maintaining the RMS error within each Zernike order. In a control condition, "synthetic" model eyes were produced by choosing each individual aberration term at random from individuals in the experimental group, and again MTFs were compared for original and randomized signs. Results were summarized by the MTF ratio: real MTF/mean simulated MTF, as a function of spatial frequency. For a 6mm pupil, the mean MTF ratio for total ocular aberrations was greater than 1.0 up to 60 cycles per degree, suggesting that the eye's aberrations are not independent and that there may be a positive functional consequences to their interrelations. This positive relation did not hold for corneal aberrations alone, or for the synthetic eyes.

  6. Aberrations of diffracted wave fields: distortion.

    PubMed

    Harvey, James E; Bogunovic, Dijana; Krywonos, Andrey

    2003-03-01

    Near-field diffraction patterns are merely aberrated Fraunhofer diffraction patterns. These aberrations, inherent to the diffraction process, provide insight and understanding into wide-angle diffraction phenomena. Nonparaxial patterns of diffracted orders produced by a laser beam passing through a grating and projected upon a plane screen exhibit severe distortion (W311). This distortion is an artifact of the configuration chosen to observe diffraction patterns. Grating behavior expressed in terms of the direction cosines of the propagation vectors of the incident and diffracted orders exhibits no distortion. Use of a simple direction cosine diagram provides an elegant way to deal with nonparaxial diffraction patterns, particularly when large obliquely incident beams produce conical diffraction.

  7. [A rare observation of intralaryngeal aberrant goiter].

    PubMed

    Gadzhimirzaev, G A; Shakhnazarov, A M; Gadzhimirzaeva, R G

    This paper was designed to report a rare observation of intralaryngeal aberrant goiter associated with goiter of the main thyroid tissue and chronic suppurative otitis media complicated by the polyp that causes occlusion of the auditory passage. The histomorphological investigation of the material harvested intraoperatively following rehabilitation of the purulent focus in the middle ear and the removal of the tumour from the inside of the right vestibular fold confirmed the diagnosis of colloid goiter.

  8. The aberrant retroesophageal right subclavian artery.

    PubMed

    Seres-Sturm, M; Maros, T N; Seres-Sturm, L

    1985-01-01

    Two cases with arteria lusoria were found at 278 routine dissections. These arteria arise as the last branches of the aortic arch and have a retroesophageal position. At the crossing point, the esophagus narrows due to the groove caused by the artery. The appearance of this malposition is the consequence of the perturbation in the organo-genesis of the right dorsal aorta and fourth branchial artery. The aberration can lead to disphagia lusoria.

  9. [Familial, structural aberration of the Y chromosome with fertility disorders].

    PubMed

    Gall, H; Schmid, M; Schmidtke, J; Schempp, W; Weber, L

    1985-11-01

    Cytogenetic studies on a patient with Klinefelter's syndrome revealed an inherited, structural aberration of the Y-chromosome which has not been described before. The aberrant Y-chromosome was characterized by eight different banding methods. The value of individual staining techniques in studies on Y-heterochromatin aberrations is emphasized. Analysis of the cytogenetic studies (banding methods, restriction endonuclease of DNA, and measurement of the length of the Y-chromosome) permits an interpretation to be made on how the aberrant Y-chromosome originated. The functions of the Y-chromosome are discussed. The decrease in fertility (cryptozoospermia) in the two brothers with the same aberrant Y-chromosome was striking.

  10. CLASSICAL AREAS OF PHENOMENOLOGY: Conformal optical design with combination of static and dynamic aberration corrections

    NASA Astrophysics Data System (ADS)

    Li, Yan; Li, Lin; Huang, Yi-Fan; Liu, Jia-Guo

    2009-02-01

    Conformal domes that are shaped to meet aerodynamic requirements can increase range and speed for the host platform. Because these domes typically deviate greatly from spherical surface descriptions, a variety of aberrations are induced which vary with the field-of-regard (FOR) angle. A system for correcting optical aberrations created by a conformal dome has an outer surface and an inner surface. Optimizing the inner surface is regard as static aberration correction. A deformable mirror is placed at the position of the secondary mirror in the two-mirror all reflective imaging system, which is the dynamic aberration correction. An ellipsoidal MgF2 conformal dome with a fineness ratio of 1.0 is designed as an example. The FOR angle is 0°- 30°, and the design wavelength is 4 μm. After the optimization at 7 zoom positions by using the design tools Code V, the root-mean-square (RMS) spot size is reduced to approximately 0.99 to 1.48 times the diffraction limit. The design results show that the performances of the conformal optical systems can be greatly improved by the combination of the static correction and the dynamic correction.

  11. DNA Repair Defects and Chromosomal Aberrations

    NASA Technical Reports Server (NTRS)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  12. Chromatic variation of aberration: the role of induced aberrations and raytrace direction

    NASA Astrophysics Data System (ADS)

    Berner, A.; Nobis, T.; Shafer, D.; Gross, H.

    2015-09-01

    The design and optimization process of an optical system contains several first order steps. The definition of the appropriate lens type and the fixation of the raytrace direction are some of them. The latter can be understood as a hidden assumption rather than an aware design step. This is usually followed by the determination of the paraxial lens layout calculated for the primary wavelength. It is obvious, that for this primary wavelength the paraxial calculations are independent of raytrace direction. Today, most of the lens designs are specified not to work only for one wavelength, but in a certain wavelength range. Considering such rays of other wavelengths, one can observe that depending on the direction there will already occur differences in the first order chromatic aberrations and additionally in the chromatic variation of the third-order aberrations. The reason for this effect are induced aberrations emerging from one surface to the following surfaces by perturbed ray heights and ray angles. It can be shown, that the total amount of surface-resolved first order chromatic aberrations and the chromatic variation of the five primary aberrations can be split into an intrinsic part and an induced part. The intrinsic part is independent of the raytrace direction whereas the induced part is not.

  13. Nodal aberration theory for wild-filed asymmetric optical systems

    NASA Astrophysics Data System (ADS)

    Chen, Yang; Cheng, Xuemin; Hao, Qun

    2016-10-01

    Nodal Aberration Theory (NAT) was used to calculate the zero field position in Full Field Display (FFD) for the given aberration term. Aiming at wide-filed non-rotational symmetric decentered optical systems, we have presented the nodal geography behavior of the family of third-order and fifth-order aberrations. Meanwhile, we have calculated the wavefront aberration expressions when one optical element in the system is tilted, which was not at the entrance pupil. By using a three-piece-cellphone lens example in optical design software CodeV, the nodal geography is testified under several situations; and the wavefront aberrations are calculated when the optical element is tilted. The properties of the nodal aberrations are analyzed by using Fringe Zernike coefficients, which are directly related with the wavefront aberration terms and usually obtained by real ray trace and wavefront surface fitting.

  14. Wavefront aberrations of x-ray dynamical diffraction beams.

    PubMed

    Liao, Keliang; Hong, Youli; Sheng, Weifan

    2014-10-01

    The effects of dynamical diffraction in x-ray diffractive optics with large numerical aperture render the wavefront aberrations difficult to describe using the aberration polynomials, yet knowledge of them plays an important role in a vast variety of scientific problems ranging from optical testing to adaptive optics. Although the diffraction theory of optical aberrations was established decades ago, its application in the area of x-ray dynamical diffraction theory (DDT) is still lacking. Here, we conduct a theoretical study on the aberration properties of x-ray dynamical diffraction beams. By treating the modulus of the complex envelope as the amplitude weight function in the orthogonalization procedure, we generalize the nonrecursive matrix method for the determination of orthonormal aberration polynomials, wherein Zernike DDT and Legendre DDT polynomials are proposed. As an example, we investigate the aberration evolution inside a tilted multilayer Laue lens. The corresponding Legendre DDT polynomials are obtained numerically, which represent balanced aberrations yielding minimum variance of the classical aberrations of an anamorphic optical system. The balancing of classical aberrations and their standard deviations are discussed. We also present the Strehl ratio of the primary and secondary balanced aberrations.

  15. Chromosomal aberrations in ISS crew members

    NASA Astrophysics Data System (ADS)

    Johannes, Christian; Goedecke, Wolfgang; Antonopoulos, Alexandra

    2012-07-01

    High energy radiation is a major risk factor in manned space missions. Astronauts and cosmonauts are exposed to ionising radiations of cosmic and solar origin, while on the Earth's surface people are well protected by the atmosphere and a deflecting magnetic field. There are now data available describing the dose and the quality of ionising radiation on-board of the International Space Station (ISS). Nonetheless, the effect of increased radiation dose on mutation rates of ISS crew members are hard to predict. Therefore, direct measurements of mutation rates are required in order to better estimate the radiation risk for longer duration missions. The analysis of chromosomal aberrations in peripheral blood lymphocytes is a well established method to measure radiation-induced mutations. We present data of chromosome aberration analyses from lymphocyte metaphase spreads of ISS crew members participating in short term (10-14 days) or long term (around 6 months) missions. From each subject we received two blood samples. The first sample was drawn about 10 days before launch and a second one within 3 days after return from flight. From lymphocyte cultures metaphase plates were prepared on glass slides. Giemsa stained and in situ hybridised metaphases were scored for chromosome changes in pre-flight and post-flight blood samples and the mutation rates were compared. Results obtained in chromosomal studies on long-term flight crew members showed pronounced inter-individual differences in the response to elevated radiation levels. Overall slight but significant elevations of typical radiation induced aberrations, i.e., dicentric chromosomes and reciprocal translocations have been observed. Our data indicate no elevation of mutation rates due to short term stays on-board the ISS.

  16. Peripheral Aberrations and Image Quality for Contact Lens Correction

    PubMed Central

    Shen, Jie; Thibos, Larry N.

    2011-01-01

    Purpose Contact lenses reduced the degree of hyperopic field curvature present in myopic eyes and rigid contact lenses reduced sphero-cylindrical image blur on the peripheral retina, but their effect on higher order aberrations and overall optical quality of the eye in the peripheral visual field is still unknown. The purpose of our study was to evaluate peripheral wavefront aberrations and image quality across the visual field before and after contact lens correction. Methods A commercial Hartmann-Shack aberrometer was used to measure ocular wavefront errors in 5° steps out to 30° of eccentricity along the horizontal meridian in uncorrected eyes and when the same eyes are corrected with soft or rigid contact lenses. Wavefront aberrations and image quality were determined for the full elliptical pupil encountered in off-axis measurements. Results Ocular higher-order aberrations increase away from fovea in the uncorrected eye. Third-order aberrations are larger and increase faster with eccentricity compared to the other higher-order aberrations. Contact lenses increase all higher-order aberrations except 3rd-order Zernike terms. Nevertheless, a net increase in image quality across the horizontal visual field for objects located at the foveal far point is achieved with rigid lenses, whereas soft contact lenses reduce image quality. Conclusions Second order aberrations limit image quality more than higher-order aberrations in the periphery. Although second-order aberrations are reduced by contact lenses, the resulting gain in image quality is partially offset by increased amounts of higher-order aberrations. To fully realize the benefits of correcting higher-order aberrations in the peripheral field requires improved correction of second-order aberrations as well. PMID:21873925

  17. Aberrations in Fresnel Lenses and Mirrors

    NASA Technical Reports Server (NTRS)

    Gregory, Don

    1999-01-01

    The NASA/MSFC Shooting Star program revealed a number of technical problems that must be solved before solar thermal propulsion can become a reality. The fundamental problem of interest here is the collection of solar energy. This is the first step in the propulsion process and indeed the most important. Everything else depends on the efficiency and focusing ability of the collection lens or mirror. An initial model of Fresnel lens behavior using a wave optics approach has been completed and the results were encouraging enough to warrant an experimental investigation. This experimental investigation confirmed some of the effects predicted and produced invaluable photographic evidence of coherence based diffraction and aberration.

  18. Microcollimated laser diode with low wavefront aberration

    SciTech Connect

    Ogata, S.; Sekii, H.; Maeda, T.; Goto, H.; Yamashita, T.; Imanaka, K. )

    1989-11-01

    The authors developed microcollimated laser diode( MCLD) utilizing a 1 mm short focal length, phi, lc 0.5 mm small diameter micro Fresnel lens (MFL) for the first time as the collimating lens. The MCLD is assembled with a 780 nm quantum-well laser diode dice and an MFL in the smallest commercial available laser package. The radiated laser beam form the MCLD has higher than 2mW power at 50 mA driving current, narrow enough as a phi 2 mm beam diameter with nearly Gaussian intensity profile, and low wavefront aberration less than {lambda}14 (rms value) measured at 1 m distance.

  19. Correction of NIRI/ Altair non-common path aberrations using focal plane sharpening

    NASA Astrophysics Data System (ADS)

    Ball, Jesse G.; Lai, Olivier; Trujillo, Chadwick; White, John

    2016-07-01

    Non-common path aberrations (NCPA), in an adaptive optics system, are static aberrations induced by the science and wavefront sensor's (WFS) separate light paths, for which the latter is corrected (although not present in the former), and the former is not. It was suspected1 that this type of aberration may significantly affect the image quality performance of Altair + NIRI, the Gemini North Observatory's adaptive optics facility instrument and the near-infrared imaging camera. A simple and effective focal plane sharpening technique was developed to optimize these static aberrations for Altair & NIRI at f/32, and 2.12μm. By varying the shape of the deformable mirror (DM) to introduce Zernike aberration coefficients through a reasonable range of values, the images produced were read out on the NIRI detector and analyzed for Strehl ratio. Fitting a second-order polynomial to this data set gave an optimized value for each coefficient out to Z49. The Strehl ratio was improved by 6% +/- 2% and the Z5 (45° astigmatism) term showed the only appreciable error contribution to the current NCPA offset of 0.15μm in k-prime (2.12μm). Aside from resulting in a slight improvement in image quality, the technique developed is non-invasive and will be implemented in other instruments and cameras that typically couple with Altair and have outdated or erroneous NCPA files currently. Furthermore, some high spatial-frequency structure in the PSF was found that limited the effect of these corrections, and may be a key component in further investigations towards image quality degradation in Altair + NIRI.

  20. Relationships between chromosome structure and chromosomal aberrations

    NASA Astrophysics Data System (ADS)

    Eidelman, Yuri; Andreev, Sergey

    An interphase nucleus of human lymphocyte was simulated by the novel Monte Carlo tech-nique. The main features of interphase chromosome structure and packaging were taken into account: different levels of chromatin organisation; nonrandom localisation of chromosomes within a nucleus; chromosome loci dynamics. All chromosomes in a nucleus were modelled as polymer globules. A dynamic pattern of intra/interchromosomal contacts was simulated. The detailed information about chromosomal contacts, such as distribution of intrachromoso-mal contacts over the length of each chromosome and dependence of contact probability on genomic separation between chromosome loci, were calculated and compared to the new exper-imental data obtained by the Hi-C technique. Types and frequencies of simple and complex radiation-induced chromosomal exchange aberrations (CA) induced by X-rays were predicted with taking formation and decay of chromosomal contacts into account. Distance dependence of exchange formation probability was calculated directly. mFISH data for human lymphocytes were analysed. The calculated frequencies of simple CA agreed with the experimental data. Complex CA were underestimated despite the dense packaging of chromosome territories within a nucleus. Possible influence of chromosome-nucleus structural organisation on the frequency and spectrum of radiation-induced chromosome aberrations is discussed.

  1. Aberrant DNA Methylation and Prostate Cancer

    PubMed Central

    Majumdar, Sunipa; Buckles, Eric; Estrada, John; Koochekpour, Shahriar

    2011-01-01

    Prostate cancer (PCa) is the most prevalent cancer, a significant contributor to morbidity and a leading cause of cancer-related death in men in Western industrialized countries. In contrast to genetic changes that vary among individual cases, somatic epigenetic alterations are early and highly consistent events. Epigenetics encompasses several different phenomena, such as DNA methylation, histone modifications, RNA interference, and genomic imprinting. Epigenetic processes regulate gene expression and can change malignancy-associated phenotypes such as growth, migration, invasion, or angiogenesis. Methylations of certain genes are associated with PCa progression. Compared to normal prostate tissues, several hypermethylated genes have also been identified in benign prostate hyperplasia, which suggests a role for aberrant methylation in this growth dysfunction. Global and gene-specific DNA methylation could be affected by environmental and dietary factors. Among other epigenetic changes, aberrant DNA methylation might have a great potential as diagnostic or prognostic marker for PCa and could be tested in tumor tissues and various body fluids (e.g., serum, urine). The DNA methylation markers are simple in nature, have high sensitivity, and could be detected either quantitatively or qualitatively. Availability of genome-wide screening methodologies also allows the identification of epigenetic signatures in high throughput population studies. Unlike irreversible genetic changes, epigenetic alterations are reversible and could be used for PCa targeted therapies. PMID:22547956

  2. Lymphocyte chromosomal aberration assay in radiation biodosimetry

    PubMed Central

    Agrawala, Paban K.; Adhikari, J. S.; Chaudhury, N. K.

    2010-01-01

    Exposure to ionizing radiations, whether medical, occupational or accidental, leads to deleterious biological consequences like mortality or carcinogenesis. It is considered that no dose of ionizing radiation exposure is safe. However, once the accurate absorbed dose is estimated, one can be given appropriate medical care and the severe consequences can be minimized. Though several accurate physical dose estimation modalities exist, it is essential to estimate the absorbed dose in biological system taking into account the individual variation in radiation response, so as to plan suitable medical care. Over the last several decades, lots of efforts have been taken to design a rapid and easy biological dosimeter requiring minimum invasive procedures. The metaphase chromosomal aberration assay in human lymphocytes, though is labor intensive and requires skilled individuals, still remains the gold standard for radiation biodosimetry. The current review aims at discussing the human lymphocyte metaphase chromosomal aberration assay and recent developments involving the application of molecular cytogenetic approaches and other technological advancements to make the assay more authentic and simple to use even in the events of mass radiation casualties. PMID:21829315

  3. Imaging System Using Shared Optics and Aberration Exploitation

    DTIC Science & Technology

    2014-02-11

    the past it has generally been accepted that the resolution of lenses with geometric aberrations cannot be increased beyond a certain threshold. In...this work we aim to overcome this limitation and demonstrate very high resolution imagery for aberrated lenses through the use of hybrid optical and...of any camera is fundamentally limited by geometric aberrations. In the past it has generally been accepted that the resolution of lenses with

  4. Spherical aberration and diffraction derived via Fourier optics

    NASA Astrophysics Data System (ADS)

    Geary, J.; Peterson, P.

    1984-02-01

    Noting that third-order spherical aberration is usually derived by way of classical geometric wavefront aberration theory, an alternative derivation is demonstrated with Fourier optics. The quadratic phase factor introduced by a lens (Goodman, 1968) is taken as the point of departure. It is shown that by extending this technique, it is possible to pick up the effect of spherical aberration, as manifested in a Fourier-optics-defined structural aberration coefficient. This coefficient is compared with the classical structural coefficient for a planoconvex lens. This difference is also demonstrated through Fresnel propagation. The effects of these differences on diffraction are investigated in the maximum Strehl planes.

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

    PubMed

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

    2014-12-20

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

  6. Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics.

    PubMed

    Dong, Bing; Li, Yan; Han, Xin-Li; Hu, Bin

    2016-09-02

    For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10(-5) in optimized correction and is 1.427 × 10(-5) in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method.

  7. Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics

    PubMed Central

    Dong, Bing; Li, Yan; Han, Xin-li; Hu, Bin

    2016-01-01

    For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10−5 in optimized correction and is 1.427 × 10−5 in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method. PMID:27598161

  8. Overlapped Fourier coding for optical aberration removal

    PubMed Central

    Horstmeyer, Roarke; Ou, Xiaoze; Chung, Jaebum; Zheng, Guoan; Yang, Changhuei

    2014-01-01

    We present an imaging procedure that simultaneously optimizes a camera’s resolution and retrieves a sample’s phase over a sequence of snapshots. The technique, termed overlapped Fourier coding (OFC), first digitally pans a small aperture across a camera’s pupil plane with a spatial light modulator. At each aperture location, a unique image is acquired. The OFC algorithm then fuses these low-resolution images into a full-resolution estimate of the complex optical field incident upon the detector. Simultaneously, the algorithm utilizes redundancies within the acquired dataset to computationally estimate and remove unknown optical aberrations and system misalignments via simulated annealing. The result is an imaging system that can computationally overcome its optical imperfections to offer enhanced resolution, at the expense of taking multiple snapshots over time. PMID:25321982

  9. Structural aberrations in group A Staphylococcus bacteriophages.

    PubMed Central

    Ackermann, H W; Berthiaume, L; Sonea, S; Kasatiya, S S

    1976-01-01

    Six related Staphylococcus phages spontaneously produced various abnormal head and tail structures: (i) giant capsids which were tailed and apparently contained nucleic acid; (ii) regular and irregular smooth polyheads; (iii) heads and polyheads with wavy outlines; (iv) mottled heads and polyheads; (v) abnormally long and short tails; and (vi) "double capsids" connected by a small bridge. Some of these structures are rare, or have not yet been reported. The frequency os specific aberrant particles varied from one phage to another. Length distribution of smooth irregular polyheads and of abnormal tails indicated that these structures assemble at random from protein synthesized in excess. These phages represent an interesting model for genetic and morphogentic studies. Images PMID:131865

  10. Patterns of Chromosomal Aberrations in Solid Tumors

    PubMed Central

    Grade, Marian; Difilippantonio, Michael J.

    2016-01-01

    Chromosomal abnormalities are a defining feature of solid tumors. Such cytogenetic alterations are mainly classified into structural chromosomal aberrations and copy number alterations, giving rise to aneuploid karyotypes. The increasing detection of these genetic changes allowed the description of specific tumor entities and the associated patterns of gene expression. In fact, tumor-specific landscapes of gross genomic copy number changes, including aneuploidies of entire chromosome arms and chromosomes result in a global deregulation of the transcriptome of cancer cells. Furthermore, the molecular characterization of cytogenetic abnormalities has provided insights into the mechanisms of tumorigenesis and has, in a few instances, led to the clinical implementation of effective diagnostic and prognostic tools, as well as treatment strategies that target a specific genetic abnormality. PMID:26376875

  11. Congenital Aberrant Tearing: A Re-Look

    PubMed Central

    Miller, Marilyn T.; Strömland, Kerstin; Ventura, Liana

    2008-01-01

    Purpose Congenital aberrant tearing is characterized by tearing when eating (“crocodile tears”), lack of emotional tearing, or both. Most reported cases are associated with Duane syndrome. In our previous studies we observed aberrant tearing in individuals with thalidomide embryopathy and Möbius sequence. This report summarizes the literature on the subject and adds 3 new studies that give information on this unusual condition. Methods Twenty-eight individuals with Möbius sequence were interviewed about tearing symptoms at a support group meeting in Italy. In Sweden 30 adults primarily from the original thalidomide series were reexamined. In this latter study, a Schirmer test was done at baseline and repeated 5 minutes after eating. Twenty families in Brazil who have children with Möbius sequence were questioned about tearing symptoms and exposure to misoprostol during pregnancy. Results In the 28 Italian individuals, either “crocodile tears” or lack of emotional tearing was noted in 7 cases. In the thalidomide study, 10 of 30 patients had tearing when eating and 7 had no emotional tearing. Low Schirmer scores or increased tearing after eating was noted in a few asymptomatic individuals. Among the 20 Brazilian children with Möbius sequence, 10 had some tearing abnormality. Conclusion Congenital anomalous lacrimation is rare but usually associated with Duane syndrome or abduction deficits, as in Möbius sequence and, less frequently, facial nerve palsy. Studies implicate an early insult in development at 4 to 6 weeks. At that time the facial nerve, sixth nerve, and lacrimal nucleus are in close proximity in the embryo. PMID:19277226

  12. Effect of chromatic aberration on atomic-resolved spherical aberration corrected STEM images.

    PubMed

    Kuramochi, Koji; Yamazaki, Takashi; Kotaka, Yasutoshi; Ohtsuka, Masahiro; Hashimoto, Iwao; Watanabe, Kazuto

    2009-12-01

    The effect of the chromatic aberration (C(c)) coefficient in a spherical aberration (C(s))- corrected electromagnetic lens on high-resolution high-angle annular dark field (HAADF) scanning transmission electron microscope (STEM) images is explored in detail. A new method for precise determination of the C(c) coefficient is demonstrated, requiring measurement of an atomic-resolution one-frame through-focal HAADF STEM image. This method is robust with respect to instrumental drift, sample thickness, all lens parameters except C(c), and experimental noise. It is also demonstrated that semi-quantitative structural analysis on the nanometer scale can be achieved by comparing experimental C(s)- corrected HAADF STEM images with their corresponding simulated images when the effects of the C(c) coefficient and spatial incoherence are included.

  13. Modified Matching Ronchi Test to Visualize Lens Aberrations

    ERIC Educational Resources Information Center

    Hassani, Kh; Ziafi, H. Hooshmand

    2011-01-01

    We introduce a modification to the matching Ronchi test to visualize lens aberrations with simple and inexpensive equipment available in educational optics labs. This method can help instructors and students to observe and estimate lens aberrations in real time. It is also a semi-quantitative tool for primary tests in research labs. In this work…

  14. Using Brief Assessments to Evaluate Aberrant Behavior Maintained by Attention.

    ERIC Educational Resources Information Center

    O'Reilly, Mark F.; Lancioni, Giulio E.; King, Lisa; Lally, Grainne; Dhomhnaill, Orla Nic

    2000-01-01

    Functional assessments were conducted for two Irish individuals with severe disabilities and aberrant behavior. A modified attention condition was introduced, which involved both parents interacting with a third person. Aberrant behavior occurred only in the modified attention condition. Successful treatment consisted of delivery of attention on a…

  15. Sextupole system for the correction of spherical aberration

    DOEpatents

    Crewe, A.V.; Kopf, D.A.

    In an electron beam device in which an electron beam is developed and then focused by a lens to a particular spot, there is provided a means for eliminating spherical aberration. A sextupole electromagnetic lens is positioned between two focusing lenses. The interaction of the sextupole with the beam compensates for spherical aberration. (GHT)

  16. Adaptive aberration correction using a triode hyperbolic electron mirror.

    PubMed

    Fitzgerald, J P S; Word, R C; Könenkamp, R

    2011-01-01

    A converging electron mirror can be used to compensate spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a novel triode (three electrode) hyperbolic mirror as an improvement to the well-known diode (two electrode) hyperbolic mirror for aberration correction. A weakness of the diode mirror is a lack of flexibility in changing the chromatic and spherical aberration coefficients independently without changes in the mirror geometry. In order to remove this limitation, a third electrode can be added. We calculate the optical properties of the resulting triode mirror analytically on the basis of a simple model field distribution. We present the optical properties-the object/image distance, z(0), and the coefficients of spherical and chromatic aberration, C(s) and C(c), of both mirror types from an analysis of electron trajectories in the mirror field. From this analysis, we demonstrate that while the properties of both designs are similar, the additional parameters in the triode mirror improve the range of aberration that can be corrected. The triode mirror is also able to provide a dynamic adjustment range of chromatic aberration for fixed spherical aberration and focal length, or any permutation of these three parameters. While the dynamic range depends on the values of aberration correction needed, a nominal 10% tuning range is possible for most configurations accompanied by less than 1% change in the other two properties.

  17. Optical aberrations measurement with a low cost optometric instrument

    NASA Astrophysics Data System (ADS)

    Furlan, Walter D.; Muñoz-Escrivá, L.; Pons, A.; Martínez-Corral, M.

    2002-08-01

    A simple experimental method for measuring optical aberrations of a single lens is proposed. The technique is based on the use of an optometric instrument employed for the assessment of the refractive state of the eye: the retinoscope. Experimental results for spherical aberration and astigmatism are obtained.

  18. Using aberration test patterns to optimize the performance of EUV aerial imaging microscopes

    SciTech Connect

    Mochi, Iacopo; Goldberg, Kenneth A.; Miyakawa, Ryan; Naulleau, Patrick; Han, Hak-Seung; Huh, Sungmin

    2009-06-16

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a prototype EUV-wavelength zoneplate microscope that provides high quality aerial image measurements of EUV reticles. To simplify and improve the alignment procedure we have created and tested arrays of aberration-sensitive patterns on EUV reticles and we have compared their images collected with the AIT to the expected shapes obtained by simulating the theoretical wavefront of the system. We obtained a consistent measure of coma and astigmatism in the center of the field of view using two different patterns, revealing a misalignment condition in the optics.

  19. Extending nodal aberration theory to include mount-induced aberrations with application to freeform surfaces.

    PubMed

    Fuerschbach, Kyle; Rolland, Jannick P; Thompson, Kevin P

    2012-08-27

    This paper introduces the path forward for the integration of freeform optical surfaces, particularly those related to φ-polynomial surfaces, including Zernike polynomial surfaces, with nodal aberration theory. With this formalism, the performance of an optical system throughout the field of view can be anticipated analytically accounting for figure error, mount-induced errors, and misalignment. Previously, only misalignments had been described by nodal aberration theory, with the exception of one special case for figure error. As an example of these new results, three point mounting error that results in a Zernike trefoil deformation is studied for the secondary mirror of a two mirror and three mirror telescope. It is demonstrated that for the case of trefoil deformation applied to a surface not at the stop, there is the anticipated field constant contribution to elliptical coma (also called trefoil) as well as a newly identified field dependent contribution to astigmatism: field linear, field conjugate astigmatism. The magnitude of this astigmatic contribution varies linearly with the field of view; however, it has a unique variation in orientation with field that is described mathematically by a concept that is unique to nodal aberration theory known as the field conjugate vector.

  20. The distribution and significance of aberrant ganglion cells in the facial nerve trunk of the cat.

    PubMed

    Satomi, H; Takahashi, K

    1986-01-01

    The distribution and peripheral connections of aberrant ganglion cells in the facial nerve trunk of the cat were studied by means of Klüver-Barrera staining and retrograde transport of horseradish peroxidase (HRP). By the Klüver-Barrera staining, aberrant ganglion cells were observed in the facial nerve trunk between the geniculate ganglion and the junction of the auricular branch of the vagus with the facial nerve trunk, although the number varied considerably with each animal. These cells were generally medium-sized and of round or oval shape, with densely stained Nissl substance, the features of which were essentially similar to those of the geniculate ganglion. In cases where HRP injections were made into the anterior wall of the auricle, several HRP-labeled cells were found ipsilaterally in the facial nerve trunk in addition to cell labeling of the geniculate ganglion. The present study in the cat demonstrated that at least some of the aberrant ganglion cells scattered in the facial nerve trunk are parental to the axons to the auricle, subserving the cutaneous sensory function.

  1. The application of information fusion in human eye aberration measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Peiming; Chen, Jiabi; Cao, Liang; Zhuang, Songlin

    2008-12-01

    A novel human eye aberration measurement method based on information fusion is presented here. We built a combined subjective and objective human eye aberration measurement system which is composed by an objective measurement part which measure human eye aberration by using Hartmann-Shack wavefront sensor and a subjective view test part through which can test the subject's vision. The deformable mirror can compensate the high order aberrations of human eye, and thus, can improve the visual acuity of human eye. We had weighting process on Zernike coefficients of both psychology stimulated results and objective results by the method of information fusion, and got combined Zernike coefficients, and finally the combined wavefront aberrations. The result shows that information fusion can combine advantages of both subjective and objective measurement, can have more comprehensive to characterized human eye visual performance, thus providing a more detailed advice for ideal individual human eye.

  2. Effects of aberrations in spatiotemporal focusing of ultrashort laser pulses.

    PubMed

    Sun, Bangshan; Salter, Patrick S; Booth, Martin J

    2014-04-01

    Spatiotemporal focusing, or simultaneous spatial and temporal focusing (SSTF), has already been adopted for various applications in microscopy, photoactivation for biological studies, and laser fabrication. We investigate the effects of aberrations on focus formation in SSTF, in particular, the effects of phase aberrations related to low-order Zernike modes and a refractive index mismatch between the immersion medium and sample. By considering a line focus, we are able to draw direct comparison between the performance of SSTF and conventional spatial focusing (SF). Wide-field SSTF is also investigated and is found to be much more robust to aberrations than either line SSTF or SF. These results show the sensitivity of certain focusing methods to specific aberrations, and can inform on the necessity and benefit of aberration correction.

  3. Chaos in ocular aberration dynamics of the human eye

    PubMed Central

    Hampson, Karen M.; Mallen, Edward A. H.

    2012-01-01

    Since the characterization of the eye’s monochromatic aberration fluctuations in 2001, the power spectrum has remained the most widely used method for analyzing their dynamics. However, the power spectrum does not capture the complexities of the fluctuations. We measured the monochromatic aberration dynamics of six subjects using a Shack-Hartmann sensor sampling at 21 Hz. We characterized the dynamics using techniques from chaos theory. We found that the attractor embedding dimension for all aberrations, for all subjects, was equal to three. The embedding lag averaged across aberrations and subjects was 0.31 ± 0.07 s. The Lyapunov exponent of the rms wavefront error was positive for each subject, with an average value of 0.44 ± 0.15 µm/s. This indicates that the aberration dynamics are chaotic. Implications for future modeling are discussed. PMID:22567581

  4. A new momenclature for structural aberrations detected by chromosome painting

    SciTech Connect

    Tucker, J.D.; Morgan, W.F.; Awa, A.A.; Bauchinger, M.; Blakey, D.; Cornforth, N.N.; Littlefield, L.G.; Natarajan, A.T.; Shasserre, C.

    1994-12-31

    The advent of chromosome painting has brought the realization that structural aberrations can be far more complex than previously imagined. Different laboratories have devised their own nomenclature systems to deal with this complexity, with the result that the terminology has become inconsistent and confusing. Recently, an international group of cytogeneticists experienced with chromosome painting convened to address this issue. The result is a systematic nomenclature capable of describing chromosome aberrations occurring between painted and unpainted chromosomes, as well as aberrations involving only painted chromosomes. The nomenclature is flexible enough to describe accurately even the most extensively rearranged chromosomes. As a consequence of this flexibility, the scheme upon which the nomenclature is based differs substantially from other systems of aberration classification. We call this system the Protocol for Aberration Identification and Nomenclature Terminology (PAINT).

  5. Wave aberrations in rhesus monkeys with vision-induced ametropias.

    PubMed

    Ramamirtham, Ramkumar; Kee, Chea-Su; Hung, Li-Fang; Qiao-Grider, Ying; Huang, Juan; Roorda, Austin; Smith, Earl L

    2007-09-01

    The purpose of this study was to investigate the relationship between refractive errors and high-order aberrations in infant rhesus monkeys. Specifically, we compared the monochromatic wave aberrations measured with a Shack-Hartman wavefront sensor between normal monkeys and monkeys with vision-induced refractive errors. Shortly after birth, both normal monkeys and treated monkeys reared with optically induced defocus or form deprivation showed a decrease in the magnitude of high-order aberrations with age. However, the decrease in aberrations was typically smaller in the treated animals. Thus, at the end of the lens-rearing period, higher than normal amounts of aberrations were observed in treated eyes, both hyperopic and myopic eyes and treated eyes that developed astigmatism, but not spherical ametropias. The total RMS wavefront error increased with the degree of spherical refractive error, but was not correlated with the degree of astigmatism. Both myopic and hyperopic treated eyes showed elevated amounts of coma and trefoil and the degree of trefoil increased with the degree of spherical ametropia. Myopic eyes also exhibited a much higher prevalence of positive spherical aberration than normal or treated hyperopic eyes. Following the onset of unrestricted vision, the amount of high-order aberrations decreased in the treated monkeys that also recovered from the experimentally induced refractive errors. Our results demonstrate that high-order aberrations are influenced by visual experience in young primates and that the increase in high-order aberrations in our treated monkeys appears to be an optical byproduct of the vision-induced alterations in ocular growth that underlie changes in refractive error. The results from our study suggest that the higher amounts of wave aberrations observed in ametropic humans are likely to be a consequence, rather than a cause, of abnormal refractive development.

  6. Genomic aberrations in spitzoid tumours and their implications for diagnosis, prognosis and therapy

    PubMed Central

    Wiesner, Thomas; Kutzner, Heinz; Cerroni, Lorenzo; Mihm, Martin J.; Busam, Klaus J.; Murali, Rajmohan

    2016-01-01

    Summary Histopathological evaluation of melanocytic tumours usually allows reliable distinction of benign melanocytic naevi from melanoma. More difficult is the histopathological classification of Spitz tumours, a heterogeneous group of tumours composed of large epithelioid or spindle-shaped melanocytes. Spitz tumours are biologically distinct from conventional melanocytic naevi and melanoma, as exemplified by their distinct patterns of genetic aberrations. Whereas conventional naevi and melanoma often harbour BRAF mutations, NRAS mutations, or inactivation of NF1, Spitz tumours show HRAS mutations, inactivation of BAP1 (often combined with BRAF mutations), or genomic rearrangements involving the kinases ALK, ROS1, NTRK1, BRAF, RET, and MET. In Spitz naevi, which lack significant histological atypia, all of these mitogenic driver aberrations trigger rapid cell proliferation, but after an initial growth phase, various tumour suppressive mechanisms stably block further growth. In some tumours, additional genomic aberrations may abrogate various tumour suppressive mechanisms, such as cell-cycle arrest, telomere shortening, or DNA damage response. The melanocytes then start to grow in a less organised fashion, may spread to regional lymph nodes, and are termed atypical Spitz tumours. Upon acquisition of even more aberrations, which often activate additional oncogenic pathways or reduce and alter cell differentiation, the neoplastic cells become entirely malignant and may colonise and take over distant organs (spitzoid melanoma). The sequential acquisition of genomic aberrations suggests that Spitz tumours represent a continuous biological spectrum, rather than a dichotomy of benign versus malignant, and that tumours with ambiguous histological features (atypical Spitz tumours) might be best classified as low-grade melanocytic tumours. The number of genetic aberrations usually correlates with the degree of histological atypia and explains why existing ancillary genetic

  7. Morphological aberrations of nutritionally deficient streptococci: association with pyridoxal (vitamin B6) concentration and potential role in antibiotic resistance.

    PubMed Central

    Clark, R B; Gordon, R E; Bottone, E J; Reitano, M

    1983-01-01

    A strain of a nutritionally deficient streptococcus was shown to undergo morphological aberrations according to pyridoxal concentrations in the growth medium. Filamentous rod-shaped cells, observed by electron microscopy, predominated in the presence of decreasing concentrations. Multiple invaginations in the outer cell wall suggested inhibition of binary fission. Penicillin antimicrobial studies performed in the presence of similar pyridoxal concentrations indicated a relationship between filamentous forms and penicillin susceptibility. Images PMID:6618670

  8. Optical aberrations of the cornea and the crystalline lens

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Wang, Zhao-Qi; Wang, Yan; Zuo, Tong

    2006-09-01

    The wave-front aberrations of the anterior corneal surface, the posterior corneal surface and the complete eye have been measured by a corneal topographic system (Orbscan II) and a Hartmann-Shack wave-front sensor. We have calculated the aberrations for both the corneal surfaces with the discrete set of corneal elevation data, and with which to acquire the aberrations of the whole cornea. The aberrations of the crystalline lens are calculated by subtracting the aberrations of the cornea from that of the complete eye. The aberration combination between the anterior and the posterior corneal surface, between the cornea and the crystalline lens is complicated, either compensation or addition. For individual Zernike terms, astigmatism and quatrefoil in the anterior corneal surface are added by the posterior corneal surface, while some other terms show compensation between the two surfacesE And for complete eye, astigmatism and spherical aberrations in the cornea are partially compensated by the crystalline lens, and other terms show addition between the two parts. Individual eye shows different combinations of compensation and addition across different Zernike terms.

  9. Aberration correction of zoom lenses using evolutionary programming.

    PubMed

    Pal, Sourav

    2013-08-10

    A systematic approach for the aberration correction of zoom systems is presented. It is assumed that the powers and movements of the components of the zoom systems are known. Each component is considered as a system of thin lenses in contact. An evolutionary algorithm is developed to explore the multivariate hyperspace of design variables formed by spherical aberration, central coma, and longitudinal chromatic aberration of each component for infinite conjugate. The primary aberrations for each component at any zoom position are deduced from three central aberration coefficients of the component for infinite conjugate using conjugate shift formulas. Overall system aberrations of the zoom systems are determined by using stop shift formulas. In most of the zoom lens systems it is important to achieve stability in the primary aberrations of the system over the zoom range. This is facilitated by proper formulation of the merit function for the optimization process. Investigations have been carried out on four-component zoom lenses, and an ab initio structure of a four-component zoom lens is presented.

  10. The Mechanisms of Aberrant Protein Aggregation

    NASA Astrophysics Data System (ADS)

    Cohen, Samuel; Vendruscolo, Michele; Dobson, Chris; Knowles, Tuomas

    2012-02-01

    We discuss the development of a kinetic theory for understanding the aberrant loss of solubility of proteins. The failure to maintain protein solubility results often in the assembly of organized linear structures, commonly known as amyloid fibrils, the formation of which is associated with over 50 clinical disorders including Alzheimer's and Parkinson's diseases. A true microscopic understanding of the mechanisms that drive these aggregation processes has proved difficult to achieve. To address this challenge, we apply the methodologies of chemical kinetics to the biomolecular self-assembly pathways related to protein aggregation. We discuss the relevant master equation and analytical approaches to studying it. In particular, we derive the underlying rate laws in closed-form using a self-consistent solution scheme; the solutions that we obtain reveal scaling behaviors that are very generally present in systems of growing linear aggregates, and, moreover, provide a general route through which to relate experimental measurements to mechanistic information. We conclude by outlining a study of the aggregation of the Alzheimer's amyloid-beta peptide. The study identifies the dominant microscopic mechanism of aggregation and reveals previously unidentified therapeutic strategies.

  11. Off-axis variable focus and aberration control mirrors

    NASA Astrophysics Data System (ADS)

    Himmer, Phillip A.; Dickensheets, David L.

    2003-01-01

    Elliptical-boundary deformable mirrors have been developed for focus control of an optical beam incident at forty-five degrees with respect to the surface normal. The mirrors are silicon nitride membranes 1.4×1 mm in size, designed to accommodate a 1 mm diameter beam. Two electrostatic actuation zones provide control over spherical aberration. Focal lengths ranging from infinity to 36 mm have been achieved, and the mirror surface figure has been characterized to quantify aberration. Residual aberrations have been observed to be less than λ/5 (peak to peak) measured at λ = 660 nm.

  12. Transmissive liquid-crystal device for correcting primary coma aberration and astigmatism in biospecimen in two-photon excitation laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Tanabe, Ayano; Hibi, Terumasa; Ipponjima, Sari; Matsumoto, Kenji; Yokoyama, Masafumi; Kurihara, Makoto; Hashimoto, Nobuyuki; Nemoto, Tomomi

    2016-12-01

    All aberrations produced inside a biospecimen can degrade the quality of a three-dimensional image in two-photon excitation laser scanning microscopy. Previously, we developed a transmissive liquid-crystal device to correct spherical aberrations that improved the image quality of a fixed-mouse-brain slice treated with an optical clearing reagent. In this study, we developed a transmissive device that corrects primary coma aberration and astigmatism. The motivation for this study is that asymmetric aberration can be induced by the shape of a biospecimen and/or by a complicated refractive-index distribution in a sample; this can considerably degrade optical performance even near the sample surface. The device's performance was evaluated by observing fluorescence beads. The device was inserted between the objective lens and microscope revolver and succeeded in improving the spatial resolution and fluorescence signal of a bead image that was originally degraded by asymmetric aberration. Finally, we implemented the device for observing a fixed whole mouse brain with a sloping surface shape and complicated internal refractive-index distribution. The correction with the device improved the spatial resolution and increased the fluorescence signal by ˜2.4×. The device can provide a simple approach to acquiring higher-quality images of biospecimens.

  13. High order aberration and straylight evaluation after cataract surgery with implantation of an aspheric, aberration correcting monofocal intraocular lens

    PubMed Central

    Kretz, Florian T A; Tandogan, Tamer; Khoramnia, Ramin; Auffarth, Gerd U

    2015-01-01

    AIM To evaluate the quality of vision in respect to high order aberrations and straylight perception after implantation of an aspheric, aberration correcting, monofocal intraocular lens (IOL). METHODS Twenty-one patients (34 eyes) aged 50 to 83y underwent cataract surgery with implantation of an aspheric, aberration correcting IOL (Tecnis ZCB00, Abbott Medical Optics). Three months after surgery they were examined for uncorrected (UDVA) and corrected distance visual acuity (CDVA), contrast sensitivity (CS) under photopic and mesopic conditions with and without glare source, ocular high order aberrations (HOA, Zywave II) and retinal straylight (C-Quant). RESULTS Postoperatively, patients achieved a postoperative CDVA of 0.0 logMAR or better in 97.1% of eyes. Mean values of high order abberations were +0.02±0.27 (primary coma components) and -0.04±0.16 (spherical aberration term). Straylight values of the C-Quant were 1.35±0.44 log which is within normal range of age matched phakic patients. The CS measurements under mesopic and photopic conditions in combination with and without glare did not show any statistical significance in the patient group observed (P≥0.28). CONCLUSION The implantation of an aspherical aberration correcting monofocal IOL after cataract surgery resulted in very low residual higher order aberration (HOA) and normal straylight. PMID:26309872

  14. VLBI measurement of the secular aberration drift

    NASA Astrophysics Data System (ADS)

    Titov, O.; Lambert, S. B.; Gontier, A.-M.

    2011-05-01

    Aims: While analyzing decades of very long baseline interferometry (VLBI) data, we detected the secular aberration drift of the extragalatic radio source proper motions caused by the rotation of the Solar System barycenter around the Galactic center. Our results agree with the predicted estimate to be 4-6 micro arcseconds per year (μas/yr) towards α = 266° and δ = -29°. In addition, we tried to detect the quadrupole systematics of the velocity field. Methods: The analysis method consisted of three steps. First, we analyzed geodetic and astrometric VLBI data to produce radio source coordinate time series. Second, we fitted proper motions of 555 sources with long observational histories over the period 1990-2010 to their respective coordinate time series. Finally, we fitted vector spherical harmonic components of degrees 1 and 2 to the proper motion field. Results: Within the error bars, the magnitude and the direction of the dipole component agree with predictions. The dipole vector has an amplitude of 6.4 ± 1.5 μas/yr and is directed towards equatorial coordinates α = 263° and δ = -20°. The quadrupole component has not been detected. The primordial gravitational wave density, integrated over a range of frequencies less than 10-9 Hz, has a limit of 0.0042h-2 where h is the normalized Hubble constant is H0/(100 km s-1). We dedicate this work to the memory of Anne-Marie Gontier, our colleague and personal friend, and a widely recognized specialist of VLBI. She passed away shortly after this paper was submitted.Proper motion data is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/529/A91

  15. MORPHOLOGICAL ABERRATION OF ARTHROBACTER GLOBIFORMIS CELLS DUE TO BIOTIN DEFICIENCY.

    PubMed

    CHAN, E C

    1964-03-01

    Chan, E. C. S. (University of New Brunswick, Fredericton, New Brunswick, Canada). Morphological aberration of Arthrobacter globiformis cells due to biotin deficiency. J. Bacteriol. 87:641-651. 1964.-Morphological aberration of Arthrobacter globiformis strain 425 was shown to occur during growth in a chemically defined medium without added biotin. Such aberrant cells could revert back to normal coccoid forms upon inoculation into fresh medium supplemented with the vitamin. This abnormal cellular development occurred even when there was good growth (turbidity) or increase in total cell mass. Light photomicrographs of negative and cell-wall stains of the organism at different times of the morphological growth cycle are presented in support of these observations. The relationship between cellular aberration and the biochemical role of biotin is briefly discussed.

  16. Multiple imaging with an aberration optimized hololens array

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, A.; Vasu, R. M.

    1989-08-01

    The imaging performance of hololenses formed with four different geometries were studied through an analysis of their third-order aberration coefficients. It is found that the geometry proposed by Brandt (1969) gives the least residual aberration with minimum variation of this aberration with the reconstruction angle. When the ideal position of one of the construction beams is changed in order to generate a hololens array, the residual aberration is found to increase sharply, which in turn affects the image resolution among the multiplied images in the output. A hololens array was generated using Brandt's geometry with the help of a one-dimensional sinusoidal grating. The results of multiple imaging with the hololens array are presented. The image resolution is reasonably high and can be further improved by reducing the f-number of the hololenses.

  17. Multiple Imaging With An Aberration Optimized Hololens Array

    NASA Astrophysics Data System (ADS)

    Kumar, A. Senthil; Vasu, R. M.

    1989-08-01

    We study the imaging performance of hololenses formed with four different geometries through an analysis of their third-order aberration coefficients. It is found that the geometry proposed by Brandt [Appl. Opt. 8(7), 1421-1429 (1969)] gives the least residual aberration with minimum variation of this aberration with the reconstruction angle. When the ideal position of one of the construction beams is changed in order to generate a hololens array, the residual aberration is found to increase sharply, which in turn affects the image resolution among the multiplied images in the output. We have generated a hololens array using Brandt's geometry with the help of a 1-D sinusoidal grating. The results of multiple imaging with the hololens array are presented. The image resolution is reasonably high and can be further improved by reducing the f-number of the hololenses.

  18. Task difficulty and aberrant behavior in severely handicapped students.

    PubMed Central

    Weeks, M; Gaylord-Ross, R

    1981-01-01

    The influence of task difficulty on aberrant behavior was investigated with three severely handicapped students. Noticeably higher rates of problem behavior occurred in demand compared to no-demand conditions. In addition, there were higher rates of problem behaviors on difficult versus easy tasks. Both these findings were validated with visual discrimination and perceptual motor tasks. An errorless learning procedure effectively minimized errors and aberrant behavior in visual discrimination tasks but not in perceptual motor tasks. It was conceptualized that aberrant behavior was maintained by negative reinforcement contingencies. Difficult tasks were aversive to the children, who emitted aberrant responses to escape or avoid such tasks. By contrast, conditions in which no demands were made, easy tasks, and, in visual discrimination learning, errorless tasks, were less aversive and resulted in little or no problem behavior. Implications for reducing maladaptive behaviors through curricular modifications are discussed and contrasted to more traditional consequence manipulation approaches. PMID:7328069

  19. Early Development of Children with Sex Chromosome Aberrations.

    ERIC Educational Resources Information Center

    Haka-Ilse, Katerina; And Others

    1978-01-01

    Arthur Retlaw and Associates, Inc., Suite 2080, 1603 Orrington Avenue, Evanston, Illinois 60201. A prospective study was made of the early development of 42 children with sex chromosome aberrations. (Author)

  20. Task difficulty and aberrant behavior in severely handicapped students.

    PubMed

    Weeks, M; Gaylord-Ross, R

    1981-01-01

    The influence of task difficulty on aberrant behavior was investigated with three severely handicapped students. Noticeably higher rates of problem behavior occurred in demand compared to no-demand conditions. In addition, there were higher rates of problem behaviors on difficult versus easy tasks. Both these findings were validated with visual discrimination and perceptual motor tasks. An errorless learning procedure effectively minimized errors and aberrant behavior in visual discrimination tasks but not in perceptual motor tasks. It was conceptualized that aberrant behavior was maintained by negative reinforcement contingencies. Difficult tasks were aversive to the children, who emitted aberrant responses to escape or avoid such tasks. By contrast, conditions in which no demands were made, easy tasks, and, in visual discrimination learning, errorless tasks, were less aversive and resulted in little or no problem behavior. Implications for reducing maladaptive behaviors through curricular modifications are discussed and contrasted to more traditional consequence manipulation approaches.

  1. Aberration vignetting phenomena and its visualization in wide angular objectives

    NASA Astrophysics Data System (ADS)

    Livshits, Irina; Letunovskaya, Marina; Potemin, Igor; Okishev, Sergey; Zhdanov, Dmitry

    2016-11-01

    Aberration vignetting phenomena changes light distribution in the image plane. A method of physically accurate simulation of this effect in optical devices is presented. We modified a stochastic ray tracing technique to use it for the analysis and visualization of the aberration vignetting. Some useful illustrations with a number of visual examples of these phenomena for different optical systems are given: bi-concentric lens, wide-angle lens, fish-eye lenses, etc.

  2. Multiplexed aberration measurement for deep tissue imaging in vivo

    PubMed Central

    Wang, Chen; Liu, Rui; Milkie, Daniel E.; Sun, Wenzhi; Tan, Zhongchao; Kerlin, Aaron; Chen, Tsai-Wen; Kim, Douglas S.; Ji, Na

    2014-01-01

    We describe a multiplexed aberration measurement method that modulates the intensity or phase of light rays at multiple pupil segments in parallel to determine their phase gradients. Applicable to fluorescent-protein-labeled structures of arbitrary complexity, it allows us to obtain diffraction-limited resolution in various samples in vivo. For the strongly scattering mouse brain, a single aberration correction improves structural and functional imaging of fine neuronal processes over a large imaging volume. PMID:25128976

  3. Wide-angle chromatic aberration corrector for the human eye.

    PubMed

    Benny, Yael; Manzanera, Silvestre; Prieto, Pedro M; Ribak, Erez N; Artal, Pablo

    2007-06-01

    The human eye is affected by large chromatic aberration. This may limit vision and makes it difficult to see fine retinal details in ophthalmoscopy. We designed and built a two-triplet system for correcting the average longitudinal chromatic aberration of the eye while keeping a reasonably wide field of view. Measurements in real eyes were conducted to examine the level and optical quality of the correction. We also performed some tests to evaluate the effect of the corrector on visual performance.

  4. Modified matching Ronchi test to visualize lens aberrations

    NASA Astrophysics Data System (ADS)

    Hassani, Kh; Hooshmand Ziafi, H.

    2011-09-01

    We introduce a modification to the matching Ronchi test to visualize lens aberrations with simple and inexpensive equipment available in educational optics labs. This method can help instructors and students to observe and estimate lens aberrations in real time. It is also a semi-quantitative tool for primary tests in research labs. In this work by comparing a single lens with a doublet, we can clearly demonstrate the superior quality of the doublet over the single lens, and estimate their conic constants.

  5. Aberrant Alternative Splicing Is Another Hallmark of Cancer

    PubMed Central

    Ladomery, Michael

    2013-01-01

    The vast majority of human genes are alternatively spliced. Not surprisingly, aberrant alternative splicing is increasingly linked to cancer. Splice isoforms often encode proteins that have distinct and even antagonistic properties. The abnormal expression of splice factors and splice factor kinases in cancer changes the alternative splicing of critically important pre-mRNAs. Aberrant alternative splicing should be added to the growing list of cancer hallmarks. PMID:24101931

  6. Wave-front aberration measurements on GRIN-rod lenses.

    PubMed

    Cline, T W; Jander, R B

    1982-03-15

    A survey of the optical quality of commercial and experimental Selfoc GRIN-rod lenses was made using a digital Twyman-Green wave-front interferometer. The technique provides an accurate and reproducible method for predicting lens performance in microoptic devices. Wave-front aberrations are reported for (1/4) pitch lenses measured in a double-pass configuration. It was found that spherical aberration is dominant in commercial lenses. SLW (1/4) pitch lenses have lower aberrations than SLS lenses and are quite suitable for microoptic devices based on fiber-to-fiber coupling. Measured multimode coupling efficiency under steady-state modal propagation is compared to measured spherical aberration for a number of lenses. The slope of the coupling dependence on spherical aberration was found to be -0.1 dB/wave. Effects due to mechanical alignment and the modal distribution in the fibers had a greater influence on the measured coupling efficiency than the contribution due the intrinsic lens aberrations, especially for the SLW lenses. Comparison of this empirical dependence with theoretical predictions for a uniform distribution, which suggests a stronger dependence, is discussed. This work suggests that commercially available GRIN-rod lenses are suitable for use in microoptic components.

  7. Generalized Alvarez lens for correction of laser aberrations

    SciTech Connect

    LaFortune, K N

    2004-12-02

    The Alvarez lens (US Patent No. 3,305,294 [1]) is a compact aberration corrector. The original design emphasized in the patent consists of a pair of adjacent optical elements that provide a variable focus. A lens system with a variable effective focal length is nothing new. Such systems are widely used in cameras, for example. It is the compactness and simplicity of operation that is the key advantage of the Alvarez lens. All of the complexity is folded into the design and fabrication of the optical elements. As mentioned in the Alvarez patent [1] and elaborated upon in Palusinski et al. [2], if one is willing to fold even more complexity into the optical elements, it is possible to correct higher-order aberrations as well. There is no theoretical limit to the number or degree of wavefront distortions that can be corrected. The only limitation is that there must be a fixed relative magnitude of the aberrations. Independent correction of each component of the higher-order aberrations can not be performed without additional elements and degrees of freedom [3]. Under some circumstances, coupling may be observed between different aberrations. This can be mitigated with the appropriate choice of design parameters. New methods are available today that increase the practicality of making higher-order aberration correctors [4,5,6].

  8. Induction of chromosome aberrations in human cells by charged particles

    NASA Technical Reports Server (NTRS)

    Wu, H.; Durante, M.; George, K.; Yang, T. C.

    1997-01-01

    Chromosome aberrations induced by high-energy charged particles in normal human lymphocytes and human fibroblasts have been investigated. The charged particles included 250 MeV/nucleon protons, 290 MeV/nucleon carbon ions and 1 GeV/nucleon iron ions. The energies of the charged particles were higher than in most of the studies reported in the literature. Lymphocytes were stimulated to grow immediately after irradiation, while fibroblasts were incubated at 37 degrees C for 24 h for repair. Chromosomes were collected at the first mitosis after irradiation and chromosome aberrations were scored using the fluorescence in situ hybridization (FISH) technique with a whole-chromosome 4 probe. Chromosome aberrations were classified as reciprocal exchanges, incomplete exchanges, deletions and complex exchanges. The relative biological effectiveness (RBE) for each type of aberration was calculated by dividing a dose of 4 Gy by the dose of the charged particles producing the same effect as 4 Gy of gamma rays. Results of this study showed that complex aberrations have the highest RBE for radiation of high linear energy transfer (LET) for human lymphocytes, but for fibroblasts, the greatest effect was for incomplete exchanges. For both lymphocytes and fibroblasts, iron ions induced a similar fraction of aberrant cells.

  9. Photolithography for the static compensation of human eye aberrations

    NASA Astrophysics Data System (ADS)

    Bara, Salvador; Jaroszewicz, Zbigniew

    2004-08-01

    Recent developments in human eye aberration measurements allow to design and fabricate compensating elements aiming to achieve aberration-limited imaging. This is important not merely from a subject's viewpoint (improving the sharpness of the outer world images formed at the retina) but mainly for clinical instrumentation purposes, especially those dealing with high-resolution retinal imaging (eye fundus cameras, scanning laser ophtlalmosopes, etc.). Here we report recent developments in the correction of the static component of the eye aberrations. Aberration data of several subjects were used for manufacturing personally customized phase plates designed to compensate for the wave aberration in the human eye. These plates were made by gray-level single-mask photosculpture in photoresist and then placed in front of the eye. The effects of misalignments as well as the strategy to design wide-field correcting elements are briefly revised. Applications include improving images in scanning laser ophtalmoscopes. The future plans of research including application of axicons for compensation of the lack of accommodation and kinoforms cancelling high amounts of eye's aberrations in monochromatic illumination are also sketched.

  10. Aberrant Glycosylation as Biomarker for Cancer: Focus on CD43

    PubMed Central

    de Laurentiis, Annamaria; Fiume, Giuseppe; Borrelli, Antonella; Tassone, Pierfrancesco; Scala, Iris; Buonaguro, Franco Maria; Quinto, Ileana; Scala, Giuseppe

    2014-01-01

    Glycosylation is a posttranslational modification of proteins playing a major role in cell signalling, immune recognition, and cell-cell interaction because of their glycan branches conferring structure variability and binding specificity to lectin ligands. Aberrant expression of glycan structures as well as occurrence of truncated structures, precursors, or novel structures of glycan may affect ligand-receptor interactions and thus interfere with regulation of cell adhesion, migration, and proliferation. Indeed, aberrant glycosylation represents a hallmark of cancer, reflecting cancer-specific changes in glycan biosynthesis pathways such as the altered expression of glycosyltransferases and glycosidases. Most studies have been carried out to identify changes in serum glycan structures. In most cancers, fucosylation and sialylation are significantly modified. Thus, aberrations in glycan structures can be used as targets to improve existing serum cancer biomarkers. The ability to distinguish differences in the glycosylation of proteins between cancer and control patients emphasizes glycobiology as a promising field for potential biomarker identification. In this review, we discuss the aberrant protein glycosylation associated with human cancer and the identification of protein glycoforms as cancer biomarkers. In particular, we will focus on the aberrant CD43 glycosylation as cancer biomarker and the potential to exploit the UN1 monoclonal antibody (UN1 mAb) to identify aberrant CD43 glycoforms. PMID:24689054

  11. Superordinate Shape Classification Using Natural Shape Statistics

    ERIC Educational Resources Information Center

    Wilder, John; Feldman, Jacob; Singh, Manish

    2011-01-01

    This paper investigates the classification of shapes into broad natural categories such as "animal" or "leaf". We asked whether such coarse classifications can be achieved by a simple statistical classification of the shape skeleton. We surveyed databases of natural shapes, extracting shape skeletons and tabulating their…

  12. Optical aberrations of intraocular lenses measured in vivo and in vitro

    NASA Astrophysics Data System (ADS)

    Barbero, Sergio; Marcos, Susana; Jiménez-Alfaro, Ignacio

    2003-10-01

    Corneal and ocular aberrations were measured in a group of eyes before and after cataract surgery with spherical intraocular lens (IOL) implantation by use of well-tested techniques developed in our laboratory. By subtraction of corneal from total aberration maps, we also estimated the optical quality of the intraocular lens in vivo. We found that aberrations in pseudophakic eyes are not significantly different from aberrations in eyes before cataract surgery or from previously reported aberrations in healthy eyes of the same age. However, aberrations in pseudophakic eyes are significantly higher than in young eyes. We found a slight increase of corneal aberrations after surgery. The aberrations of the IOL and the lack of balance of the corneal spherical aberrations by the spherical aberrations of the intraocular lens also degraded the optical quality in pseudophakic eyes. We also measured the aberrations of the IOL in vitro, using an eye cell model, and simulated the aberrations of the IOL on the basis of the IOL's physical parameters. We found a good agreement among in vivo, in vitro, and simulated measures of spherical aberration: Unlike the spherical aberration of the young crystalline lens, which tends to be negative, the spherical aberration of the IOL is positive and increases with lens power. Computer simulations and in vitro measurements show that tilts and decentrations might be contributors to the increased third-order aberrations in vivo in comparison with in vitro measurements.

  13. Tuning fifth-order aberrations in a Quadrupole-Octupole Corrector

    SciTech Connect

    Lupini, Andrew R; Pennycook, Stephen J

    2012-01-01

    The resolution of conventional electron microscopes is usually limited by spherical aberration. Microscopes equipped with aberration-correctors are then primarily limited by higher-order, chromatic, and misalignment aberrations. In particular the Nion third-order aberration correctors installed on machines with a low energy spread and possessing sophisticated alignment software were limited by the uncorrected fifth-order aberrations. Here we show how the Nion fifth-order aberration corrector can be used to adjust and reduce some of the fourth and fifth-order aberrations in a probe-corrected scanning transmission electron microscope.

  14. Analytical approach to the impact of polarization aberration on lithographic imaging.

    PubMed

    Tu, Yuanying; Wang, Xiangzhao; Li, Sikun; Cao, Yuting

    2012-06-01

    An analytical approach to the impact of polarization aberration on lithographic imaging is proposed. The linear relationship between image placement error (IPE) of alternating phase-shifting mask (Alt-PSM) and odd aberration items of polarization aberrations, as well as that between best focus shift (BFS) of Alt-PSM and even aberration items of polarization aberrations are established by analytical equations, respectively. The validity of the linear relationships is demonstrated by numerical results. The differences and connections between scalar aberration and polarization aberration are briefly discussed based on these linear relationships.

  15. Focal aberrations of large-aperture HOPG von-Hàmos x-ray spectrometers

    NASA Astrophysics Data System (ADS)

    Zastrau, U.; Brown, C. R. D.; Döppner, T.; Glenzer, S. H.; Gregori, G.; Lee, H. J.; Marschner, H.; Toleikis, S.; Wehrhan, O.; Förster, E.

    2012-09-01

    Focal aberrations of large-aperture highly oriented pyrolytic graphite (HOPG) crystals in von-Hàmos geometry are investigated by experimental and computational methods. A mosaic HOPG crystal film of 100 μm thickness diffracts 8 keV x-rays. This thickness is smaller than the absorption depth of the symmetric 004-reflection, which amounts to 257 μm. Cylindrically bent crystals with 110mm radius of curvature and up to 100 mm collection width produce a X-shaped halo around the focus. This feature vanishes when the collection aperture is reduced, but axial spectral profiles show that the resolution is not affected. X-ray topography reveals significant inhomogeneous crystallite domains of 2±1mm diameter along the entire crystal. Rocking curves shift by about ±20arcmin between domains, while their full width at half-maximum varies between 30 and 50 arcmin. These inhomogeneities are not imprinted at the focal spot, since the monochromatically reflecting area of the crystal is large compared to inhomogeneities. Ray-tracing calculations using a Monte-Carlo-based algorithm developed for mosaic crystals reproduce the X-shaped halo in the focal plane, stemming from the mosaic defocussing in the non-dispersive direction in combination with large apertures. The best achievable resolution is found by analyzing a diversity of rocking curve widths, source sizes and crystal thicknesses for 8 keV x-rays to be ΔE/E ~ 10-4. Finally a general analytic expression for the shape of the aberration is derived.

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

    PubMed

    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.

  17. The effects of aberrations (low order and quilting) on the performance of the all-composite design for the Herschel Space Observatory

    NASA Technical Reports Server (NTRS)

    Catanzaro, B.; Thomas, James A.; Backovsky, S.; Barber, D.; Small, D.; Johnston, R.; Cohen, E. J.

    2001-01-01

    The effects of specific aberrations on the optical performance of the all-composite design for the Herschel Space Observatory are examined. A review of the all-composite design for the large aperture (3.5 m) telescope that satisfies the target specifications is presented. Cryogenic experiments with carbon fiber reinforced polymer (CFRP) 2 m demonstration mirror have yielded empirical bounds on the high-and low-order spatial frequency aberrations that will be anticipated in the full 3.5 m Ritchey-Chretien telescope design. Detailed analysis is presented on the effect of the low order aberrations of the primary mirror on the system wavefront error and encircled energy. Predictable limits of correction via low order shaping of the secondary mirror are described. The impact of higher order surface errors on the encircled energy and the stray light will also be presented. Comments are made regarding the impact of the optical prescription and CRFP design on flight telescope testing.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Time sequence of events leading to chromosomal aberration formation

    SciTech Connect

    Moore, R.C. ); Bender, M.A. )

    1993-01-01

    Investigations have been carried out on the influence of the repair polymerases on the yield of different types of chromosomal aberrations. The studies were mainly concerned with the effect of inhibiting the polymerases on the yield of aberrations. The polymerases fill in single-strand regions, and the fact that their inhibition affects the yield of aberrations suggests that single-strand lesions are influential in aberration formation. The results indicate that there are two actions of polymerases in clastogenesis. One is in their involvement in a G[sub 2] repair system, in which either of the two chromatids is concerned, and which does not yield aberrations unless the inhibition is still operating when the cells enter mitosis. The second is such that when repair is inhibited, further damage accrues. The second action is affected by inhibiting polymerase repair, but also operates even when the repair enzymes are active. The production of chromosomal exchanges involves a series of reactions, some of which are reversible. The time span over which the reactions occur is much longer than has been envisaged previously.

  20. Time sequence of events leading to chromosomal aberration formation

    SciTech Connect

    Moore, R.C.; Bender, M.A.

    1993-05-01

    Investigations have been carried out on the influence of the repair polymerases on the yield of different types of chromosomal aberrations. The studies were mainly concerned with the effect of inhibiting the polymerases on the yield of aberrations. The polymerases fill in single-strand regions, and the fact that their inhibition affects the yield of aberrations suggests that single-strand lesions are influential in aberration formation. The results indicate that there are two actions of polymerases in clastogenesis. One is in their involvement in a G{sub 2} repair system, in which either of the two chromatids is concerned, and which does not yield aberrations unless the inhibition is still operating when the cells enter mitosis. The second is such that when repair is inhibited, further damage accrues. The second action is affected by inhibiting polymerase repair, but also operates even when the repair enzymes are active. The production of chromosomal exchanges involves a series of reactions, some of which are reversible. The time span over which the reactions occur is much longer than has been envisaged previously.

  1. Focusing of an elliptical mirror based system with aberrations

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Ai, Min; Zhang, He; Wang, Chao; Tan, Jiubin

    2013-10-01

    The effect of primary aberrations on the focusing of an elliptical mirror based system is studied by using the Debye integral. Specifically, the apodization function for elliptical mirror is derived and expressed by the eccentricity of the elliptical mirror. For the elliptical mirror with low aperture, intensity distributions in the presence of aberrations near focus are presented based on the derived scalar theory, while for the high-aperture condition, vectorial theory is used to describe the electric field in the focal region. In particular, the effect of aberrations is studied under radially polarized illumination. Moreover, tolerance conditions are given based on the knowledge of focusing with aberrations. It is found that the elliptical mirror based system shares a similar level of tolerance conditions with that of the single lens, while both of them are more sensitive to the presence of astigmatism than other aberrations. It is believed that the results will theoretically support the application of the high-aperture elliptical mirror in scanning microscopy.

  2. Sub-ångstrom resolution using aberration corrected electron optics

    NASA Astrophysics Data System (ADS)

    Batson, P. E.; Dellby, N.; Krivanek, O. L.

    2002-08-01

    Following the invention of electron optics during the 1930s, lens aberrations have limited the achievable spatial resolution to about 50 times the wavelength of the imaging electrons. This situation is similar to that faced by Leeuwenhoek in the seventeenth century, whose work to improve the quality of glass lenses led directly to his discovery of the ubiquitous ``animalcules'' in canal water, the first hints of the cellular basis of life. The electron optical aberration problem was well understood from the start, but more than 60 years elapsed before a practical correction scheme for electron microscopy was demonstrated, and even then the remaining chromatic aberrations still limited the resolution. We report here the implementation of a computer-controlled aberration correction system in a scanning transmission electron microscope, which is less sensitive to chromatic aberration. Using this approach, we achieve an electron probe smaller than 1Å. This performance, about 20 times the electron wavelength at 120keV energy, allows dynamic imaging of single atoms, clusters of a few atoms, and single atomic layer `rafts' of atoms coexisting with Au islands on a carbon substrate. This technique should also allow atomic column imaging of semiconductors, for detection of single dopant atoms, using an electron beam with energy below the damage threshold for silicon.

  3. Minimum change in spherical aberration that can be perceived

    PubMed Central

    Manzanera, Silvestre; Artal, Pablo

    2016-01-01

    It is important to know the visual sensitivity to optical blur from both a basic science perspective and a practical point of view. Of particular interest is the sensitivity to blur induced by spherical aberration because it is being used to increase depth of focus as a component of a presbyopic solution. Using a flicker detection-based procedure implemented on an adaptive optics visual simulator, we measured the spherical aberration thresholds that produce just-noticeable differences in perceived image quality. The thresholds were measured for positive and negative values of spherical aberration, for best focus and + 0.5 D and + 1.0 D of defocus. At best focus, the SA thresholds were 0.20 ± 0.01 µm and −0.17 ± 0.03 µm for positive and negative spherical aberration respectively (referred to a 6-mm pupil). These experimental values may be useful in setting spherical aberration permissible levels in different ophthalmic techniques. PMID:27699113

  4. Chromosome aberrations as biomarkers of radiation exposure: Modelling basic mechanisms

    NASA Astrophysics Data System (ADS)

    Ballarini, F.; Ottolenghi, A.

    The space radiation environment is a mixed field consisting of different particles having different energies, including high charge and energy (HZE) ions. Conventional measurements of absorbed doses may not be sufficient to completely characterise the radiation field and perform reliable estimates of health risks. Biological dosimetry, based on the observation of specific radiation-induced endpoints (typically chromosome aberrations), can be a helpful approach in case of monitored exposure to space radiation or other mixed fields, as well as in case of accidental exposure. Furthermore, various ratios of aberrations (e.g. dicentric chromosomes to centric rings and complex exchanges to simple exchanges) have been suggested as possible fingerprints of radiation quality, although all of them have been subjected to some criticisms. In this context a mechanistic model and a Monte Carlo code for the simulation of chromosome aberration induction were developed. The model, able to provide dose-responses for different aberrations (e.g. dicentrics, rings, fragments, translocations, insertions and other complex exchanges), was further developed to assess the dependence of various ratios of aberrations on radiation quality. The predictions of the model were compared with available data, whose experimental conditions were faithfully reproduced. Particular attention was devoted to the scoring criteria adopted in different laboratories and to possible biases introduced by interphase death and mitotic delay. This latter aspect was investigated by taking into account both metaphase data and data obtained with Premature Chromosome Condensation (PCC).

  5. Risk estimation based on chromosomal aberrations induced by radiation

    NASA Technical Reports Server (NTRS)

    Durante, M.; Bonassi, S.; George, K.; Cucinotta, F. A.

    2001-01-01

    The presence of a causal association between the frequency of chromosomal aberrations in peripheral blood lymphocytes and the risk of cancer has been substantiated recently by epidemiological studies. Cytogenetic analyses of crew members of the Mir Space Station have shown that a significant increase in the frequency of chromosomal aberrations can be detected after flight, and that such an increase is likely to be attributed to the radiation exposure. The risk of cancer can be estimated directly from the yields of chromosomal aberrations, taking into account some aspects of individual susceptibility and other factors unrelated to radiation. However, the use of an appropriate technique for the collection and analysis of chromosomes and the choice of the structural aberrations to be measured are crucial in providing sound results. Based on the fraction of aberrant lymphocytes detected before and after flight, the relative risk after a long-term Mir mission is estimated to be about 1.2-1.3. The new technique of mFISH can provide useful insights into the quantification of risk on an individual basis.

  6. Antimutagenic potential of curcumin on chromosomal aberrations in Allium cepa *

    PubMed Central

    Ragunathan, Irulappan; Panneerselvam, Natarajan

    2007-01-01

    Turmeric has long been used as a spice and food colouring agent in Asia. In the present investigation, the antimutagenic potential of curcumin was evaluated in Allium cepa root meristem cells. So far there is no report on the biological properties of curcumin in plant test systems. The root tip cells were treated with sodium azide at 200 and 300 µg/ml for 3 h and curcumin was given at 5, 10 and 20 µg/ml for 16 h, prior to sodium azide treatment. The tips were squashed after colchicine treatment and the cells were analyzed for chromosome aberration and mitotic index. Curcumin induces chromosomal aberration in Allium cepa root tip cells in an insignificant manner, when compared with untreated control. Sodium azide alone induces chromosomal aberrations significantly with increasing concentrations. The total number of aberrations was significantly reduced in root tip cells pretreated with curcumin. The study reveals that curcumin has antimutagenic potential against sodium azide induced chromosomal aberrations in Allium cepa root meristem cells. In addition, it showed mild cytotoxicity by reducing the percentage of mitotic index in all curcumin treated groups, but the mechanism of action remains unknown. The antimutagenic potential of curcumin is effective at 5 µg/ml in Allium cepa root meristem cells. PMID:17610326

  7. Chromosome aberrations as biomarkers of radiation quality: modelling basic mechanisms

    NASA Astrophysics Data System (ADS)

    Ottolenghi, A.; Ballarini, F.

    Since space radiation consists of a mixed field of different particles having different energies, including HZE ions, conventional measurements of absorbed doses are not sufficient to completely characterise the radiation field and perform reliable estimates of health risks. Biological dosimetry, based on the observation of specific radiation-induced endpoints (typically chromosome aberrations) after exposure, can be a helpful approach in case of monitored exposure to space radiation or other mixed fields, as well as in case of accidental exposure. Although various ratios of aberrations (e.g. dicentrics to centric rings and complex exchanges to simple exchanges) have been suggested as possible biomarkers both in theoretical and in experimental studies, all of them have been subjected to some criticisms. In this context a mechanistic model and a Monte Carlo code for the simulation of chromosome aberrations was developed. The model, able to provide dose-responses for different aberrations (e.g. dicentrics, rings, translocations, insertions and other complex exchanges), was further developed to assess the dependence of various ratios of aberrations on radiation quality. The predictions of the model were compared with available data, whose experimental conditions were faithfully reproduced. Particular attention was devoted to the scoring criteria adopted in different laboratories and to possible biases introduced by interphase death and mitotic delay; this latter aspect was investigated by taking into account both metaphase data and data obtained with PCC (Premature Chromosome Condensation).

  8. Effects of contrast medium on radiation-induced chromosome aberrations

    SciTech Connect

    Matsubara, S.; Suzuki, S.; Suzuki, H.; Kuwabara, Y.; Okano, T.

    1982-07-01

    The effects of contrast material (meglumine iothalamate) on radiation-induced chromosome aberrations were investigated in studies on the lymphocytes of patients who had undergone diagnostic radiography and in in vitro experiments with diagnostic x rays and /sup 60/Co gamma rays. Chromosome and chromatid aberrations were found to increase significantly with increasing concentrations of contrast material that were added at irradiation. However, the aberrations were not associated with elevation of the ratio of dicentric and ring chromosomes to the number of cells with unstable chromosome aberrations at the first mitosis. Lymphocytes irradiated in the absence of contrast material did not show an increase in chromosome-type aberrations when the agent was given in increasing concentrations during subsequent incubation, but there were greater numbers of chromatid gaps and breaks. When lymphocytes were exposed to 400 R (103.2 mC/kg) of /sup 60/Co gamma rays, the presence of contrast agent did not increase the yield of dicentric and ring chromosomes, but induced a marked delay in cell proliferation, especially in lymphocytes with more heavily damaged chromosomes. In additional examination, the contrast agent itself induced sister chromatid exchanges in lymphocytes.

  9. Differential aberration correction (DAC) microscopy: a new molecular ruler.

    PubMed

    Vallotton, P

    2008-11-01

    Considerable efforts have been deployed towards measuring molecular range distances in fluorescence microscopy. In the 1-10 nm range, Förster energy transfer microscopy is difficult to beat. Above 300 nm, conventional diffraction limited microscopy is suitable. We introduce a simple experimental technique that allows bridging the gap between those two resolution scales in both 2D and 3D with a resolution of about 20 nm. The method relies on a computational approach to accurately correct optical aberrations over the whole field of view. The method is differential because the probes of interest are affected in exactly the same manner by aberrations as are the reference probes used to construct the aberration deformation field. We expect that this technique will have significant implications for investigating structural and functional questions in bio-molecular sciences.

  10. Conformal dome aberration correction by designing the inner surface

    NASA Astrophysics Data System (ADS)

    Zhang, Wang; Chen, Shouqian; Fan, Zhigang

    2016-12-01

    The ray transmission models of optical domes were established, and the characteristics of the rays while passing through a hemispherical dome and a conformal dome were comparatively analysed. Acquiring the minimum deviated angles from the inner surface of the conformal dome was then determined to be the designing goal for reducing the dynamic aberrations. Based on this, the inner surface of the conformal dome was optimized and thus, the dynamic aberrations were reduced. Finally, a completely cooled conformal optical system was designed. The results show that the optical system have produced good imaging quality within all the fields of regard, which further illustrates that designing the inner surface of a conformal dome is an effective method for aberration correction.

  11. [Chromosome aberrations in workers in a printing press].

    PubMed

    Pelclová, D; Rössner, P; Pícková, J; Hykes, P

    1990-08-10

    Using cytogenetic analysis of peripheral lymphocytes the authors examined three groups of subjects: 42 rotogravure printers exposed to toluene in concentrations of 400-4400 mg.m-3 for a mean period of 13 years, 28 administrative employees of the printing plant exposed to low concentrations of toluene (8-16 mg.m-3) in their offices, whereby more than half of them spent on average two hours in the photogravure workshop, and 32 control subjects. In the printers 3.64% subjects, in the office staff 3.32% aberrant cells were found. The difference between the control group and the two groups from the printing plant was highly significant as regards the number of aberrant cells (P less than 0.005) and chromatid breaks and number of breaks per cell. The higher frequency of aberrant cells in probably associated with exposure to toluene, gravure printing dyes and in all three groups also with the highly contaminated communal atmosphere.

  12. Adaptive phase aberration correction based on imperialist competitive algorithm.

    PubMed

    Yazdani, R; Hajimahmoodzadeh, M; Fallah, H R

    2014-01-01

    We investigate numerically the feasibility of phase aberration correction in a wavefront sensorless adaptive optical system, based on the imperialist competitive algorithm (ICA). Considering a 61-element deformable mirror (DM) and the Strehl ratio as the cost function of ICA, this algorithm is employed to search the optimum surface profile of DM for correcting the phase aberrations in a solid-state laser system. The correction results show that ICA is a powerful correction algorithm for static or slowly changing phase aberrations in optical systems, such as solid-state lasers. The correction capability and the convergence speed of this algorithm are compared with those of the genetic algorithm (GA) and stochastic parallel gradient descent (SPGD) algorithm. The results indicate that these algorithms have almost the same correction capability. Also, ICA and GA are almost the same in convergence speed and SPGD is the fastest of these algorithms.

  13. Aberrant Protein S-Nitrosylation in Neurodegenerative Diseases

    PubMed Central

    Nakamura, Tomohiro; Tu, Shichun; Akhtar, Mohd Waseem; Sunico, Carmen R.; Okamoto, Shu-ichi; Lipton, Stuart A.

    2013-01-01

    S-Nitrosylation is a redox-mediated posttranslational modification that regulates protein function via covalent reaction of nitric oxide (NO)-related species with a cysteine thiol group on the target protein. Under physiological conditions, S-nitrosylation can be an important modulator of signal transduction pathways, akin to phosphorylation. However, with aging or environmental toxins that generate excessive NO, aberrant S-nitrosylation reactions can occur and affect protein misfolding, mitochondrial fragmentation, synaptic function, apoptosis or autophagy. Here, we discuss how aberrantly S-nitrosylated proteins (SNO-proteins) play a crucial role in the pathogenesis of neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases. Insight into the pathophysiological role of aberrant S-nitrosylation pathways will enhance our understanding of molecular mechanisms leading to neurodegenerative diseases and point to potential therapeutic interventions. PMID:23719160

  14. Ischemic Stroke Injury Is Mediated by Aberrant Cdk5

    PubMed Central

    Meyer, Douglas A.; Torres-Altoro, Melissa I.; Tan, Zhenjun; Tozzi, Alessandro; Di Filippo, Massimiliano; DiNapoli, Vincent; Plattner, Florian; Kansy, Janice W.; Benkovic, Stanley A.; Huber, Jason D.; Miller, Diane B.; Greengard, Paul; Calabresi, Paolo; Rosen, Charles L.

    2014-01-01

    Ischemic stroke is one of the leading causes of morbidity and mortality. Treatment options are limited and only a minority of patients receive acute interventions. Understanding the mechanisms that mediate neuronal injury and death may identify targets for neuroprotective treatments. Here we show that the aberrant activity of the protein kinase Cdk5 is a principal cause of neuronal death in rodents during stroke. Ischemia induced either by embolic middle cerebral artery occlusion (MCAO) in vivo or by oxygen and glucose deprivation in brain slices caused calpain-dependent conversion of the Cdk5-activating cofactor p35 to p25. Inhibition of aberrant Cdk5 during ischemia protected dopamine neurotransmission, maintained field potentials, and blocked excitotoxicity. Furthermore, pharmacological inhibition or conditional knock-out (CKO) of Cdk5 prevented neuronal death in response to ischemia. Moreover, Cdk5 CKO dramatically reduced infarctions following MCAO. Thus, targeting aberrant Cdk5 activity may serve as an effective treatment for stroke. PMID:24920629

  15. In vivo chromosome aberration test for hydroxyapetite in mice.

    PubMed

    Kannan, T P; Nik Ahmad Shah, N L; Azlina, A; Samsudin, A R; Narazah, M Y; Salleh, Ma'arof

    2004-05-01

    This study evaluates the cytotoxic and mutagenic effect of synthetic hydroxyapatite granules (source: School of Material and Mineral Resources Engineering, Universiti Sains Malaysia) in the bone marrow cells of mice. Mice are exposed to synthetic hydroxyapatite granules, the bone marrow cells are collected and observed for chromosome aberrations. No chromosome aberrations were noticed in the animals exposed to distilled water (negative control) and to the test substance, synthetic hydroxyapatite granules (treatment) groups. Chromosome aberrations were observed in the animals exposed to Mitomycin C (positive control group). There was no indication of cytotoxicity due to synthetic hydroxyapatite granules in the animals as revealed by the mitotic index. Hence, synthetic hydroxyapatite granules are considered non-mutagenic under the prevailing test conditions.

  16. Low chromatic aberration hexapole for molecular state selection

    NASA Astrophysics Data System (ADS)

    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%.

  17. Dynamic compensation of chromatic aberration in a programmable diffractive lens.

    PubMed

    Millán, María S; Otón, Joaquín; Pérez-Cabré, Elisabet

    2006-10-02

    A proposal to dynamically compensate chromatic aberration of a programmable phase Fresnel lens displayed on a liquid crystal device and working under broadband illumination is presented. It is based on time multiplexing a set of lenses, designed with a common focal length for different wavelengths, and a tunable spectral filter that makes each sublens work almost monochromatically. Both the tunable filter and the sublens displayed by the spatial light modulator are synchronized. The whole set of sublenses are displayed within the integration time of the sensor. As a result the central order focalization has a unique location at the focal plane and it is common for all selected wavelengths. Transversal chromatic aberration of the polychromatic point spread function is reduced by properly adjusting the pupil size of each sublens. Longitudinal chromatic aberration is compensated by making depth of focus curves coincident for the selected wavelengths. Experimental results are in very good agreement with theory.

  18. Measuring chromatic aberrations in imaging systems using plasmonic nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Chromatic aberration in optical systems arises from the wavelength dependence of a glass's refractive index. Polychromatic rays incident upon an optical surface are refracted at slightly different angles and in traversing an optical system follow distinct paths creating images displaced according to color. Although arising from dispersion, it manifests as a spatial distortion correctable only with compound lenses with multiple glasses and accumulates in complicated imaging systems. While chromatic aberration is measured with interferometry, simple methods are attractive for their ease of use and low cost. In this letter we retrieve the longitudinal chromatic focal shift of high numerical aperture (NA) microscope objectives from the extinction spectra of metallic nanoparticles within the focal plane. The method is accurate for high NA objectives with apochromatic correction, and enables rapid assessment of the chromatic aberration of any complete microscopy systems, since it is straightforward to implement

  19. Generation of microswimmers from passive Brownian particles in a spherically aberrated optical trap.

    PubMed

    Mondal, Argha; Roy, Basudev; Banerjee, Ayan

    2015-03-23

    We induce spontaneous motion that is both directed and complex in micron-sized asymmetric Brownian particles in a spherically aberrated optical trap to generate microswimmers. The aberrated optical trap is prepared in a slightly modified optical tweezers configuration where we use a refractive index mismatched cover slip leading to the formation of an annular intensity distribution near the trap focal plane. Asymmetric scattering from a micro-particle trapped in this annular trap gives rise to a net tangential force on the particle causing it to revolve spontaneously in the intensity ring. The rate of revolution can be controlled from sub-Hz to a few Hz by changing the intensity of the trapping light. Theoretical simulations performed using finite-difference time-domain method verify the experimental observations. We also experimentally demonstrate simultaneous spin and revolution of a micro-swimmer which shows that complex motion can be achieved by designing a suitable shape of a micro-swimmer in the optical potential.

  20. Aberrant hepatic arteries running through pancreatic parenchyma encountered during pancreatoduodenectomy

    PubMed Central

    Wang, Lei; Xu, Jianwei; Sun, Dong; Zhang, Zongli

    2016-01-01

    Abstract Background: Aberrant hepatic arteries (HAs) encountered during pancreatoduodenectomy are difficult to manage. Mehtods: Two cases with rare types of aberrant HA running through the pancreatic parenchyma were reviewed. Results: The first case, a 68-year-old man, was admitted with obstructive jaundice. A tumor of the pancreatic head and aberrant HAs were suspected on computed tomography (CT) scan. At laparotomy, a new variation was identified; namely, 2 aberrant arteries—a right replaced HA and middle HA (RMHA) that both originated from the superior mesenteric artery (SMA) and ran via intrapancreatic paths posterior and anterior to the pancreatic head, respectively. Branches of the RMHA to the pancreas were ligated and severed and the trunk preserved. The RMHA was mistakenly identified as an aberrant left HA (RLHA), whereas the RLHA was overlooked and not dissected intraoperatively. CT angiography performed 11 days postoperatively identified that the RLHA originated from the left gastric artery (LGA). The second case had a variation of Michels IX. A 58-year-old woman presented with obstructive jaundice and a distal cholangiocarcinoma was suspected on the basis of enhanced CT scan. At laparotomy, the common hepatic artery (CHA) was found to originate entirely from the SMA and run posterior to the pancreatic head via an intrapancreatic path. The segment of CHA in the pancreatic parenchyma was removed and reconstructed with the LGA. Conclusions: Preoperative identification of aberrant HAs helps in planning appropriate operative procedures and minimizing unnecessary complications. Both preservation and reconstruction of these arteries are technically safe and feasible; however, preservation is preferable. PMID:27930504

  1. Chromosome aberration assays in genetic toxicology testing in vitro.

    PubMed

    Ishidate, M; Miura, K F; Sofuni, T

    1998-08-03

    The chromosome aberration test using cultured mammalian cells is one of the sensitive methods to predict environmental mutagens and/or carcinogens, and is a complementary test to the Salmonella/microsome assay (Ames test). From our recent survey of 951 chemicals which have been tested for their clastogenicity in cultured mammalian cells such as Chinese hamster fibroblasts or human lymphocytes, it was noted that 47% of them are consistently positive either with or without metabolic activation. When the test was performed using the cell line CHL/IU, 39.2% (292/745) were found to be positive. However, 8% (36/447) of such clastogens were positive only at an extremely high concentration of more than 10 mM. About 11% (48/447) of clastogens such as diethylstilbestrol (DES) and methyl AalphaC (Glob-P-1) induced mainly polyploid cells. Most chemicals induced chromatid-type aberrations, some induce only break-type aberrations at relatively high dose levels, but others induce more exchange-type aberrations at relatively low dose levels. Clastogenic activities were compared among different clastogens, using the D20 value, which is the minimum dose (mg/ml) at which aberrations were found in 20% of metaphases. In addition, the translocation (TR) value was calculated from the incidence of cells with exchange-type aberrations. It was suggested that possible carcinogens are included in the group of compounds with relatively low D20 values, but with high TR values. Karyological analysis was performed, using a FISH painting probe prepared from No. 1 chromosome of CHO cells, on the clonal subline isolated after treatment with benzo(a)pyrene. However, no specific changes common to the agent were detected. Laser scanning cytometry (LSC) was also applied to screen for abnormal karyotypes. A translocation between particular chromosomes was reflected by the deletion of a DNA peak.

  2. Measurement of eye aberrations in a speckle field

    SciTech Connect

    Larichev, A V; Ivanov, P V; Iroshnikov, N G; Shmalgauzen, V I

    2001-12-31

    The influence of speckles on the performance of a Shark-Hartmann wavefront sensor is investigated in the eye aberration studies. The dependence of the phase distortion measurement error on the characteristic speckle size is determined experimentally. Scanning of the reference source was used to suppress the speckle structure of the laser beam scattered by the retina. The technique developed by us made it possible to study the time dependence of the human eye aberrations with a resolution of 30 ms. (laser applications and other topics in quantum electronics)

  3. Chromatic aberration effect on solar energy systems using Fresnel lenses

    SciTech Connect

    Lorenzo, E.

    1981-11-01

    In concentration systems using Fresnel lenses the effect of the chromatic aberration can become important. In this paper we propose a method to take this effect into account for designing purposes. Also we define a parameter that allows one to estimate the degradation of the thermodynamic quality of the concentrator due to this effect. This parameter follows a hyperbolic law, with the acceptance angle showing that it is important to consider chromatic aberration when modeling concentrators with a high concentration factor. However, this complexity is unnecessary for moderate or low concentration factors.

  4. A study on optical aberrations in parabolic neutron guides

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Wang, Hongli; Liu, Yuntao; Zu, Yong; He, Linfeng; Wei, Guohai; Sun, Kai; Han, Songbai; Chen, Dongfeng

    2015-06-01

    It is widely believed that a neutron beam can be focused to a small spot using a parabolic guide, which will significantly improve the flux. However, researchers have also noted challenges for the neutron inhomogeneous phase space distribution in parabolic focusing guide systems. In this paper, the sources of most prominent optical aberrations, such as an inhomogeneous phase space distribution and irregular divergence distribution, are discussed, and an optimization solution is also proposed. We indicate that optimizing the parabolic guide geometrical configuration removes almost all of the aberrations and yields a considerable intensity gain factor.

  5. Description of optical aberrations in dynamic Fresnel dish concentrators

    SciTech Connect

    Borton, D.N.; Borton, C.J.

    1995-10-01

    Tracking solar dish concentrators have the highest efficiencies of solar devices. Traditional paraboloidal dish systems have the best optics, but are limited in size by mechanical constraints. Fresnel dishes can be made larger and are cheaper than paraboloidal dishes, but have optical imperfections. This paper describes a mathematical model of a dynamic Fresnel dish concentrator, and examines its optics. Optical aberrations of any design can be described for any day of the year. In general, the aberrations are small and the benefits of a Fresnel design outweigh the loss in optical performance. The model can be used to design concentrators for any application including distributed dish electric power generating systems.

  6. Aberration Theory - A Spectrum Of Design Techniques For The Perplexed

    NASA Astrophysics Data System (ADS)

    Shafer, David

    1986-10-01

    The early medieval scholar Maimonides wrote a famous book called "Guide for the Perplexed", which explained various thorny philosophical and religious questions for the benefit of the puzzled novice. I wish I had had such a person to guide me when I first started a career in lens design. There the novice is often struck by how much of an "art" this endeavor is. The best bet, for a beginner with no experience, should be to turn to optical aberration theory - which, in principle, should explain much of what goes into designing an optical system. Unfortunately, this subject is usually presented in the form of proofs and derivations, with little time spent on the practical implications of aberration theory. Furthermore, a new generation of lens designers, who grew up with the computer, often consider aberration theory as an unnecessary relic from the past. My career, by contrast, is based on the conviction that using the results of aberration theory is the only intelligent way to design optical systems. Computers are an invaluable aide, but we must, ultimately, bite the bullet and think. Along these lines, I have given several papers over the last few years which deal directly with the philosophy of lens design; the kind of guides for the perplexed that I wished I had had from the start. These papers include: "Lens design on a desert island - A simple method of optical design", "A modular method of optical design", "Optical design with air lenses", "Optical design with 'phantom' aspherics", "Optical design methods: your head as a personal computer", "Aberration theory and the meaning of life", and a paper at Innsbruck - "Some interesting correspondences in aberration theory". In all cases, the emphasis is on using your head to think, and the computer to help you out with the numerical work and the "fine-tuning" of a design. To hope that the computer will do the thinking for you is folly. Solutions gained by this route rarely equal the results of an experienced and

  7. Increased frequency of chromosomal aberrations in railroad car painters.

    PubMed

    Piña-Calva, A; Madrigal-Bujaidar, E; Fuentes, M V; Neria, P; Pérez-Lucio, C; Vélez-Zamora, N M

    1991-01-01

    The purpose of this study was to determine if exposure to paints and solvents contributes to chromosomal alterations in occupationally exposed individuals. A total of 25 male railroad and underground railroad car painters were studied. This group had a mean age of 32.7 y and a mean exposure time of 5.2 y. The results were compared with those obtained for 25 healthy (unexposed) males. The scoring of structural chromosome aberrations clearly revealed an increase in the number of all types of aberrations considered in the population of painters. This suggests that exposure to a combination of chemicals may increase genotoxicity in industrial workers.

  8. An integrative characterization of recurrent molecular aberrations in glioblastoma genomes.

    PubMed

    Sintupisut, Nardnisa; Liu, Pei-Ling; Yeang, Chen-Hsiang

    2013-10-01

    Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumor in adults. Decades of investigations and the recent effort of the Cancer Genome Atlas (TCGA) project have mapped many molecular alterations in GBM cells. Alterations on DNAs may dysregulate gene expressions and drive malignancy of tumors. It is thus important to uncover causal and statistical dependency between 'effector' molecular aberrations and 'target' gene expressions in GBMs. A rich collection of prior studies attempted to combine copy number variation (CNV) and mRNA expression data. However, systematic methods to integrate multiple types of cancer genomic data-gene mutations, single nucleotide polymorphisms, CNVs, DNA methylations, mRNA and microRNA expressions and clinical information-are relatively scarce. We proposed an algorithm to build 'association modules' linking effector molecular aberrations and target gene expressions and applied the module-finding algorithm to the integrated TCGA GBM data sets. The inferred association modules were validated by six tests using external information and datasets of central nervous system tumors: (i) indication of prognostic effects among patients; (ii) coherence of target gene expressions; (iii) retention of effector-target associations in external data sets; (iv) recurrence of effector molecular aberrations in GBM; (v) functional enrichment of target genes; and (vi) co-citations between effectors and targets. Modules associated with well-known molecular aberrations of GBM-such as chromosome 7 amplifications, chromosome 10 deletions, EGFR and NF1 mutations-passed the majority of the validation tests. Furthermore, several modules associated with less well-reported molecular aberrations-such as chromosome 11 CNVs, CD40, PLXNB1 and GSTM1 methylations, and mir-21 expressions-were also validated by external information. In particular, modules constituting trans-acting effects with chromosome 11 CNVs and cis-acting effects with chromosome

  9. Papillary Carcinoma in Median Aberrant Thyroid (Ectopic) - Case Report

    PubMed Central

    K, Shashidhar; Deshmane, Vijaya Laxmi; Kumar, Veerendra; Arjunan, Ravi

    2014-01-01

    Median ectopic thyroid may be encountered anywhere from the foramen caecum to the diaphragm. Non lingual median aberrant thyroid (incomplete descent) usually found in the infrahyoid region and malignant transformation in this ectopic thyroid tissue is very rare. We report an extremely rare case of papillary carcinoma in non lingual median aberrant thyroid in a 25-year-old female. The differentiation between a carcinoma arising in the median ectopic thyroid tissue and a metastatic papillary carcinoma from an occult primary in the main thyroid gland is also discussed. PMID:25121039

  10. Aberration compensation and resolution improvement of focus modulation microscopy

    NASA Astrophysics Data System (ADS)

    Zheng, Juanjuan; Gao, Peng; Shao, Xiaopeng

    2017-01-01

    Confocal laser scanning microscopy (CLSM) has wide applications in biological research and medical diagnosis. However, the spatial resolution and signal to noise ratio (SNR) of CLSM is reduced in the presence of an aberration. Here we improve the pupil-segmentation method to measure and compensate for aberrations in focus modulation CLSM (FM-CLSM), which uses Gaussian-type and doughnut-like foci to scan a sample in sequence. As a result, FM-CLSM can provide images with a high resolution and a high SNR for biomedical or industrial applications.

  11. Study the most favorable shapes of electrostatic quadrupole doublet lenses

    NASA Astrophysics Data System (ADS)

    Hussein, O. A.; Sise, O.

    2017-02-01

    The optical properties of an electrostatic quadrupole doublet lens with two different electrode shapes were studied with the aid of computer simulation. The optimal electrode voltages of the electrostatic quadrupole lenses which give the stigmatic image in both planes simultaneously were found for both concave cylindrical electrode shape and plan electrode shape of the operation mode: parallel to point focusing. The effect of electrode shape on the image properties was investigated, and the aberration figures were studied. The results showed that under the same operation condition and the geometrical dimensions, the changing of the electrode shape of the electrostatic quadrupole doublet lenses lead to important differences in the optical properties of the lenses and the characteristics of the systems.

  12. Aberrant topology of striatum's connectivity is associated with the number of episodes in depression.

    PubMed

    Meng, Chun; Brandl, Felix; Tahmasian, Masoud; Shao, Junming; Manoliu, Andrei; Scherr, Martin; Schwerthöffer, Dirk; Bäuml, Josef; Förstl, Hans; Zimmer, Claus; Wohlschläger, Afra M; Riedl, Valentin; Sorg, Christian

    2014-02-01

    In major depressive disorder, depressive episodes reoccur in ∼60% of cases; however, neural mechanisms of depressive relapse are poorly understood. Depressive episodes are characterized by aberrant topology of the brain's intrinsic functional connectivity network, and the number of episodes is one of the most important predictors for depressive relapse. In this study we hypothesized that specific changes of the topology of intrinsic connectivity interact with the course of episodes in recurrent depressive disorder. To address this hypothesis, we investigated which changes of connectivity topology are associated with the number of episodes in patients, independently of current symptoms and disease duration. Fifty subjects were recruited including 25 depressive patients (two to 10 episodes) and 25 gender- and age-matched control subjects. Resting-state functional magnetic resonance imaging, Harvard-Oxford brain atlas, wavelet-transformation of atlas-shaped regional time-series, and their pairwise Pearson's correlation were used to define individual connectivity matrices. Matrices were analysed by graph-based methods, resulting in outcome measures that were used as surrogates of intrinsic network topology. Topological scores were subsequently compared across groups, and, for patients only, related with the number of depressive episodes and current symptoms by partial correlation analysis. Concerning the whole brain connectivity network of patients, small-world topology was preserved but global efficiency was reduced and global betweenness-centrality increased. Aberrant nodal efficiency and centrality of regional connectivity was found in the dorsal striatum, inferior frontal and orbitofrontal cortex as well as in the occipital and somatosensory cortex. Inferior frontal changes were associated with current symptoms, whereas aberrant right putamen network topology was associated with the number of episodes. Results were controlled for effects of total grey matter

  13. Effect of Adlay ( Coix lachryma-jobi L. var. ma-yuen Stapf) Testa and its phenolic components on Cu2+-treated low-density lipoprotein (LDL) oxidation and lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages.

    PubMed

    Huang, Din-Wen; Kuo, Yueh-Hsiung; Lin, Fang-Yi; Lin, Yun-Lian; Chiang, Wenchang

    2009-03-25

    The aims of this study were to investigate the effects of adlay testa (AT) on Cu(2+)-treated low-density lipoprotein (LDL) oxidation, 2,2'-diphenyl-1-picrylhydrazyl (DPPH)-scavenging capacity, and lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages and determine its active components. The AT ethanolic extract (ATE) was partitioned into four fractions by various solvents as follows: n-hexane (ATE-Hex), ethyl acetate (ATE-Ea), n-butanol (ATE-Bu), and water (ATE-H(2)O). ATE-Ea and ATE-Bu were further fractionated into ATE-Ea-a-ATE-Ea-h and ATE-Bu-A-ATE-Bu-F, respectively, by column chromatography. Results showed that ATE-Ea, ATE-Bu, ATE-Ea-e, and ATE-Bu-C expressed antiradical, antioxidative, and anti-inflammatory activities with respect to the DPPH-scavenging capacity, LDL protection effect, and nitric oxide (NO) inhibitory activity. Inflammation was further modulated by ATE-Ea, ATE-Bu, ATE-Ea-e, and ATE-Bu-C through downregulating the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) proteins. The following components were found in ATE-Ea-e and ATE-Bu-C after purification and high-performance liquid chromatographic analysis: chlorogenic acid (CGA), vanillic acid (VA), caffeic acid (CA), p-coumaric acid (PCA), ferulic acid (FA), and 2-O-beta-glucopyranosyl-7-methoxy-4((2)H)-benzoxazin-3-one (GMBO). Results showed that CGA, CA, and FA were the major components responsible for the antioxidative and anti-inflammatory activities of ATE-Ea-e and ATE-Bu-C. Subsequently, each gram of ATE-Bu-C had 30.3 mg of CGA, 9.02 mg of CA, and 189 mg of GMBO, while each gram of ATE-Ea-e had 1.31 mg of VA, 3.89 mg of PCA, and 47.6 microg of FA. In conclusion, ATE has antioxidative and anti-inflammatory activities, and its effects are partially related to its phenolic components. Thus, ATE has the potential to be developed as a functional food targeting chronic diseases.

  14. Shape-Shifting Plastic

    SciTech Connect

    2015-05-20

    A new plastic developed by ORNL and Washington State University transforms from its original shape through a series of temporary shapes and returns to its initial form. The shape-shifting process is controlled through changes in temperature

  15. Measurement of large low-order aberrations by using a series of through-focus Ronchigrams.

    PubMed

    Akima, Hisanao; Yoshida, Takaho

    2014-08-01

    A method for measuring large aberrations up to second order (defocus, 2-fold astigmatism and axial coma), which uses a through-focus series of Ronchigrams, is proposed. The method is based on the principle that line-focus conditions in Ronchigrams can be locally detected and low-order aberrations can thereby be measured. The proposed method provides auto-tuning of large low-order aberration; in particular, iterative aberration measurement and correction reduce low-order aberrations from several thousand nanometers to less than a few hundred nanometers, which can be handled by conventional fine-aberration tuning methods.

  16. Aberrant Pattern of Scanning in Prosopagnosia Reflects Impaired Face Processing

    ERIC Educational Resources Information Center

    Stephan, Blossom Christa Maree; Caine, Diana

    2009-01-01

    Visual scanpath recording was used to investigate the information processing strategies used by a prosopagnosic patient, SC, when viewing faces. Compared to controls, SC showed an aberrant pattern of scanning, directing attention away from the internal configuration of facial features (eyes, nose) towards peripheral regions (hair, forehead) of the…

  17. Using Aberrant Behaviors as Reinforcers for Autistic Children.

    ERIC Educational Resources Information Center

    Charlop, Marjorie H.; And Others

    1990-01-01

    Three experiments assessed the efficacy of various reinforcers to increase correct task responding in a total of 10 autistic children, aged 6-9. Of the reinforcers used (stereotypy, delayed echolalia, perseverative behavior, and food), task performance was highest with opportunities to engage in aberrant behaviors, and lowest with edible…

  18. The Aberrant Salience Inventory: A New Measure of Psychosis Proneness

    ERIC Educational Resources Information Center

    Cicero, David C.; Kerns, John G.; McCarthy, Denis M.

    2010-01-01

    Aberrant salience is the unusual or incorrect assignment of salience, significance, or importance to otherwise innocuous stimuli and has been hypothesized to be important for psychosis and psychotic disorders such as schizophrenia. Despite the importance of this concept in psychosis research, no questionnaire measures are available to assess…

  19. Benzene-induced chromosome aberrations: A follow-up study

    SciTech Connect

    Forni, A.

    1996-12-01

    To study the evolution of cytogenetic damage from past exposure to high concentrations of benzene and its health significance, chromosome aberrations (CA) in lymphocytes were reinvestigated after approximately 20 years in four subjects with past severe hemopathy and in seven controls studied in the late 1960s. Increased chromosome-type aberrations were still present up to 30 years after benzene toxicity, but blood counts were normal. The vital status at the end of 1993 was ascertained for 32 subjects with a history of benzene toxicity and for 31 controls studied for CA from 1965 to 1970, who differed significantly for CA rates. Of the 32 benzene-exposed subjects, 1 was lost to follow-up, 20 were still alive, and 11 had died at ages 36 to 83, between 1 and 20 years after the last CA study. Five deaths were from neoplasia (acute erythroleukemia, brain tumor, cancer of lung, paranasal cavity, esophagus). The deceased subjects had significantly higher rates of chromosome-type aberrations than those alive, and those who died of neoplasia had the highest rates of these aberrations in the last study before death or diagnosis of cancer. Out of the 31 controls, 12 had died from 4 to 23 years after the CA study. Three deaths were from neoplasia (two lung cancer, one brain tumor). Even if this is a small sample, the results suggest a higher risk of cancer for the benzene-exposed cohort, who had persistently high CA rates in lymphocytes. 10 refs., 4 tabs.

  20. Chromosome aberrations in plants as a monitoring system.

    PubMed Central

    Grant, W F

    1978-01-01

    The potential of higher plants as a first-tier assay system for detecting chemical mutagens is evaluated. The use of plant tissue (primarily root tips and pollen mother cells) for studying the induction of chromosomal aberrations is one of the oldest, simplest, most reliable, and inexpensive methods available. Specific types of abnormalities have been induced by different classes of pesticides. Chromosome clumping, contraction, stickiness, paling, fragmentation, dissolution, chromosome and chromatid bridges, C-mitosis, and endoploidy have been reported in the literature. Examples of cytogenetic studies with pesticides demonstrating the usefulness of higher plants as a monitoring system are reviewed. Pesticides which cause chromosome aberrations in plant cells also produce chromosome aberrations in cultured animal cells. Frequently, the aberrations are identical. For example, studies have shown that compounds which have a C-mitotic effect on plant cells have the same effect on animal cells. It is recommended that plant systems be accepted as a first-tier assay system for the detection of possible genetic damage by environmental chemicals. PMID:367773

  1. [Cytogenetic aberrations in histologically benign infiltratively growing sphenoid wing meningiomas].

    PubMed

    Korshunov, A G; Cherekaev, V A; Bekiashev, A Kh; Sycheva, R V

    2007-01-01

    Meningiomas of the sphenoid wing (SW) frequently show an invasive pattern of growth and cause destruction of the adjacent structures. As a result, the rate of recurrent SW meningiomas is as high as 30%. Cytogenetic investigations showed no aberrations specific to invasively growing meningiomas. During this study, the authors evaluated 10 invasive and 5 non-invasive SW meningiomas via comparative genome hybridization (CGH) (matrix CGH), by using the gene chips of GenoSensor Array micromatrixes. The mean number of aberrations in the tumor cells was much greater in case of invasive meningiomas (67.4 versus 40.5 in case of non-invasive SW meningiomas. Furthermore, in invasive SW meningiomas, there were frequently losses in loci 1p, 6q, and 14q and gains in loci 15q and 10, which had been predetermined as molecular markers of stepwise progression of meningioma. Thus, the presence of a complex cytogenetic profile and progression-associated chromosome aberrations in benign SW meningiomas is linked with the increase of their invasive potential. Due to the fact that there are no well-defined adjuvant therapy regimens for recurring meningiomas at present, the revealed genomic aberrations may become potential targets for searching for drugs and a therapeutic intervention in future.

  2. Aberrant nerve fibres within the central nervous system.

    PubMed

    Moffie, D

    1992-01-01

    Three cases of aberrant nerve fibres in the spinal cord and medulla oblongata are described. The literature on these fibres is discussed and their possible role in regeneration. Different views on the possibility of regeneration or functional recovery of the central nervous system are mentioned in the light of recent publications, which are more optimistic than before.

  3. Mapping magnetism with atomic resolution using aberrated electron probes

    NASA Astrophysics Data System (ADS)

    Idrobo, Juan; Rusz, Ján; McGuire, Michael A.; Symons, Christopher T.; Vatsavai, Ranga Raju; Lupini, Andrew R.

    2015-03-01

    In this talk, we report a direct experimental real-space mapping of magnetic circular dichroism with atomic resolution in aberration-corrected scanning transmission electron microscopy (STEM). Using an aberrated electron probe with customized phase distribution, we reveal with electron energy-loss (EEL) spectroscopy the checkerboard antiferromagnetic ordering of Mn moments in LaMnAsO by observing a dichroic signal in the Mn L-edge. The aberrated probes allow the collection of EEL spectra using the transmitted beam, which results in a magnetic circular dichroic signal with intrinsically larger signal-to-noise ratios than those obtained via nanodiffraction techniques (where most of the transmitted electrons are discarded). The novel experimental setup presented here, which can easily be implemented in aberration-corrected STEM, opens new paths for probing dichroic signals in materials with unprecedented spatial resolution. This research was supported by DOE SUFD MSED, by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US DOE, and by the Swedish Research Council and Swedish National Infrastructure for Computing (NSC center)

  4. Nanowire growth kinetics in aberration corrected environmental transmission electron microscopy

    SciTech Connect

    Chou, Yi -Chia; Panciera, Federico; Reuter, Mark C.; Stach, Eric A.; Ross, Frances M.

    2016-03-15

    Here, we visualize atomic level dynamics during Si nanowire growth using aberration corrected environmental transmission electron microscopy, and compare with lower pressure results from ultra-high vacuum microscopy. We discuss the importance of higher pressure observations for understanding growth mechanisms and describe protocols to minimize effects of the higher pressure background gas.

  5. The pterygo-spinous muscle--an aberrant (atavic) remnant.

    PubMed

    Nathan, H

    1989-01-01

    We report here on an aberrant pterygoid muscle found during a dissection of the infratemporal fossa. We have not noted such a muscle in hundreds of dissections in the area. A few anatomical texts (Piersol, 1911; Testut, Latarjet, 1931) have referred to its possible existence as the pterygo-spinous muscle.

  6. DNA test--a forensic boon.

    PubMed

    Mohanty, Nayan Kishore; Haldar, Swaraj

    2006-02-01

    DNA fingerprinting (DNAFP) profiles can be applied to identify an individual in criminal as well as in civil cases. The main advantage of the technique is its ability to analyse small and environmentally challenged samples and to accurately establish their origins with a high degree of certainty: DNAFP can identify an individual in criminal and civil cases eg, rape, kidnapping, assassination and so on. The forensic DNA analysis can be stored in a data bank. It can help in crime prevention by giving the information of potential criminals. Reliability of DNA technique is very important. In paternity and maternity identification, when called for, DNA testing plays very much positive role.

  7. Chromatin structure and ionizing-radiation-induced chromosome aberrations

    SciTech Connect

    Muehlmann-Diaz, M.C.

    1993-01-01

    The possible influence of chromatic structure or activity on chromosomal radiosensitivity was studied. A cell line was isolated which contained some 10[sup 5] copies of an amplified plasmid in a single large mosquito artificial chromosome (MAC). This chromosome was hypersensitive to DNase I. Its radiosensitivity was some three fold greater than normal mosquito chromosomes in the same cell. In cultured human cells irradiated during G[sub 0], the initial breakage frequency in chromosome 4, 19 and the euchromatic and heterochromatic portions of the Y chromosome were measured over a wide range of doses by inducing Premature Chromosome Condensation (PCC) immediately after irradiation with Cs-137 gamma rays. No evidence was seen that Y heterochromatin or large fragments of it remained unbroken. The only significant deviation from the expected initial breakage frequency per Gy per unit length of chromosome was that observed for the euchromatic portion of the Y chromosome, with breakage nearly twice that expected. The development of aberrations involving X and Y chromosomes at the first mitosis after irradation was also studied. Normal female cells sustained about twice the frequency of aberrations involving X chromosomes for a dose of 7.3 Gy than the corresponding male cells. Fibroblasts from individuals with supernumerary X chromosomes did not show any further increase in X aberrations for this dos. The frequency of aberrations involving the heterochromatic portion of the long arm of the Y chromosome was about what would be expected for a similar length of autosome, but the euchromatic portion of the Y was about 3 times more radiosensitive per unit length. 5-Azacytidine treatment of cultured human female fibroblasts or fibroblasts from a 49,XXXXY individual, reduced the methylation of cytosine residues in DNA, and resulted in an increased chromosomal radiosensitivity in general, but it did not increase the frequency of aberrations involving the X chromosomes.

  8. Non-Gaussianity and CMB aberration and Doppler

    SciTech Connect

    Catena, Riccardo; Liguori, Michele; Renzi, Alessandro; Notari, Alessio E-mail: michele.liguori@pd.infn.it E-mail: arenzi@pd.infn.it

    2013-09-01

    The peculiar motion of an observer with respect to the CMB rest frame induces a deflection in the arrival direction of the observed photons (also known as CMB aberration) and a Doppler shift in the measured photon frequencies. As a consequence, aberration and Doppler effects induce non trivial correlations between the harmonic coefficients of the observed CMB temperature maps. In this paper we investigate whether these correlations generate a bias on non-Gaussianity estimators f{sub NL}. We perform this analysis simulating a large number of temperature maps with Planck-like resolution (lmax = 2000) as different realizations of the same cosmological fiducial model (WMAP7yr). We then add to these maps aberration and Doppler effects employing a modified version of the HEALPix code. We finally evaluate a generalization of the Komatsu, Spergel and Wandelt non-Gaussianity estimator for all the simulated maps, both when peculiar velocity effects have been considered and when these phenomena have been neglected. Using the value v/c = 1.23 × 10{sup −3} for our peculiar velocity, we found that the aberration/Doppler induced non-Gaussian signal is at most of about half of the cosmic variance σ for f{sub NL} both in a full-sky and in a cut-sky experimental configuration, for local, equilateral and orthogonal estimators. We conclude therefore that when estimating f{sub NL} it is safe to ignore aberration and Doppler effects if the primordial map is already Gaussian. More work is necessary however to assess whether a map which contains non-Gaussianity can be significantly distorted by a peculiar velocity.

  9. Canine urothelial carcinoma: genomically aberrant and comparatively relevant

    PubMed Central

    Shapiro, S. G.; Raghunath, S.; Williams, C.; Motsinger-Reif, A. A.; Cullen, J. M.; Liu, T.; Albertson, D.; Ruvolo, M.; Lucas, A. Bergstrom; Jin, J.; Knapp, D. W.; Schiffman, J. D.

    2015-01-01

    Urothelial carcinoma (UC), also referred to as transitional cell carcinoma (TCC), is the most common bladder malignancy in both human and canine populations. In human UC, numerous studies have demonstrated the prevalence of chromosomal imbalances. Although the histopathology of the disease is similar in both species, studies evaluating the genomic profile of canine UC are lacking, limiting the discovery of key comparative molecular markers associated with driving UC pathogenesis. In the present study, we evaluated 31 primary canine UC biopsies by oligonucleotide array comparative genomic hybridization (oaCGH). Results highlighted the presence of three highly recurrent numerical aberrations: gain of dog chromosome (CFA) 13 and 36 and loss of CFA 19. Regional gains of CFA 13 and 36 were present in 97% and 84% of cases, respectively, and losses on CFA 19 were present in 77% of cases. Fluorescence in situ hybridization (FISH), using targeted bacterial artificial chromosome (BAC) clones and custom Agilent SureFISH probes, was performed to detect and quantify these regions in paraffin-embedded biopsy sections and urine-derived urothelial cells. The data indicate that these three aberrations are potentially diagnostic of UC. Comparison of our canine oaCGH data with that of 285 human cases identified a series of shared copy number aberrations. Using an informatics approach to interrogate the frequency of copy number aberrations across both species, we identified those that had the highest joint probability of association with UC. The most significant joint region contained the gene PABPC1, which should be considered further for its role in UC progression. In addition, cross-species filtering of genome-wide copy number data highlighted several genes as high-profile candidates for further analysis, including CDKN2A, S100A8/9, and LRP1B. We propose that these common aberrations are indicative of an evolutionarily conserved mechanism of pathogenesis and harbor genes key to

  10. Image transfer with spatial coherence for aberration corrected transmission electron microscopes.

    PubMed

    Hosokawa, Fumio; Sawada, Hidetaka; Shinkawa, Takao; Sannomiya, Takumi

    2016-08-01

    The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field's components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field's derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope.

  11. Optimal principal component analysis-based numerical phase aberration compensation method for digital holography.

    PubMed

    Sun, Jiasong; Chen, Qian; Zhang, Yuzhen; Zuo, Chao

    2016-03-15

    In this Letter, an accurate and highly efficient numerical phase aberration compensation method is proposed for digital holographic microscopy. Considering that most parts of the phase aberration resides in the low spatial frequency domain, a Fourier-domain mask is introduced to extract the aberrated frequency components, while rejecting components that are unrelated to the phase aberration estimation. Principal component analysis (PCA) is then performed only on the reduced-sized spectrum, and the aberration terms can be extracted from the first principal component obtained. Finally, by oversampling the reduced-sized aberration terms, the precise phase aberration map is obtained and thus can be compensated by multiplying with its conjugation. Because the phase aberration is estimated from the limited but more relevant raw data, the compensation precision is improved and meanwhile the computation time can be significantly reduced. Experimental results demonstrate that our proposed technique could achieve both high compensating accuracy and robustness compared with other developed compensation methods.

  12. From Shape to Letters.

    ERIC Educational Resources Information Center

    Schiller, Hillel A.

    In order to make letter shape recognition an integral part of perception training, the use of the line in its two basic shapes is proposed. Letter shapes may seem exceedingly complex linear shapes to young minds. Thus instead of instruction in configuration, instruction involving transformational activities to manipulate and create the…

  13. Shape memory polymers

    DOEpatents

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  14. Third-order aberration analysis of an off-axial optical system

    NASA Astrophysics Data System (ADS)

    Wakazono, Tsuyoshi; Yatagai, Toyohiko; Araki, Keisuke

    2016-02-01

    The aberration theory applied to co-axial optical systems is extended to off-axial systems, for which third-order aberration coefficients are considered. The derived aberrations are analyzed using three-dimensional ray bundles, spot diagrams, and image charts, and classified in relation to the system symmetry. This theory is very useful for optical designers, allowing them to clarify the relationship between the structures of off-axial optical systems and the corresponding off-axial aberrations.

  15. [Aberrations of the alarm call of the steppe marmot, Marmota bobak (Rodentia, Sciuridae)].

    PubMed

    Nikol'skiĭ, A A

    2008-01-01

    Aberrations, or deviations from the normal type of alarm call have been studied in the steppe marmot. One regular and several rare aberrations have been identified. The regular aberration manifests itself in all six populations studied, from the Kharkov Region in the west to the eastern border of the Orenburg Region in the east, with its frequency in the populations varying in different years from 10 to 66%. Rare aberrations occur sporadically and not in all populations.

  16. Lowered threshold energy for femtosecond laser induced optical breakdown in a water based eye model by aberration correction with adaptive optics.

    PubMed

    Hansen, Anja; Géneaux, Romain; Günther, Axel; Krüger, Alexander; Ripken, Tammo

    2013-06-01

    In femtosecond laser ophthalmic surgery tissue dissection is achieved by photodisruption based on laser induced optical breakdown. In order to minimize collateral damage to the eye laser surgery systems should be optimized towards the lowest possible energy threshold for photodisruption. However, optical aberrations of the eye and the laser system distort the irradiance distribution from an ideal profile which causes a rise in breakdown threshold energy even if great care is taken to minimize the aberrations of the system during design and alignment. In this study we used a water chamber with an achromatic focusing lens and a scattering sample as eye model and determined breakdown threshold in single pulse plasma transmission loss measurements. Due to aberrations, the precise lower limit for breakdown threshold irradiance in water is still unknown. Here we show that the threshold energy can be substantially reduced when using adaptive optics to improve the irradiance distribution by spatial beam shaping. We found that for initial aberrations with a root-mean-square wave front error of only one third of the wavelength the threshold energy can still be reduced by a factor of three if the aberrations are corrected to the diffraction limit by adaptive optics. The transmitted pulse energy is reduced by 17% at twice the threshold. Furthermore, the gas bubble motions after breakdown for pulse trains at 5 kilohertz repetition rate show a more transverse direction in the corrected case compared to the more spherical distribution without correction. Our results demonstrate how both applied and transmitted pulse energy could be reduced during ophthalmic surgery when correcting for aberrations. As a consequence, the risk of retinal damage by transmitted energy and the extent of collateral damage to the focal volume could be minimized accordingly when using adaptive optics in fs-laser surgery.

  17. The BHVI-EyeMapper: Peripheral Refraction and Aberration Profiles

    PubMed Central

    Fedtke, Cathleen; Ehrmann, Klaus; Falk, Darrin; Bakaraju, Ravi C.; Holden, Brien A.

    2014-01-01

    ABSTRACT Purpose The aim of this article was to present the optical design of a new instrument (BHVI-EyeMapper, EM), which is dedicated to rapid peripheral wavefront measurements across the visual field for distance and near, and to compare the peripheral refraction and higher-order aberration profiles obtained in myopic eyes with and without accommodation. Methods Central and peripheral refractive errors (M, J180, and J45) and higher-order aberrations (C[3, 1], C[3, 3], and C[4, 0]) were measured in 26 myopic participants (mean [±SD] age, 20.9 [±2.0] years; mean [±SD] spherical equivalent, −3.00 [±0.90] diopters [D]) corrected for distance. Measurements were performed along the horizontal visual field with (−2.00 to −5.00 D) and without (+1.00 D fogging) accommodation. Changes as a function of accommodation were compared using tilt and curvature coefficients of peripheral refraction and aberration profiles. Results As accommodation increased, the relative peripheral refraction profiles of M and J180 became significantly (p < 0.05) more negative and the profile of M became significantly (p < 0.05) more asymmetric. No significant differences were found for the J45 profiles (p > 0.05). The peripheral aberration profiles of C[3, 1], C[3, 3], and C[4, 0] became significantly (p < 0.05) less asymmetric as accommodation increased, but no differences were found in the curvature. Conclusions The current study showed that significant changes in peripheral refraction and higher-order aberration profiles occurred during accommodation in myopic eyes. With its extended measurement capabilities, that is, permitting rapid peripheral refraction and higher-order aberration measurements up to visual field angles of ±50 degrees for distance and near (up to −5.00 D), the EM is a new advanced instrument that may provide additional insights in the ongoing quest to understand and monitor myopia development. PMID:25105690

  18. Dependence of the wave-front aberration on the radius of the reference sphere.

    PubMed

    Miks, Antonín

    2002-06-01

    Wave-front aberration is a basic characteristic of the imaging properties of optical systems. The value of the wave-front aberration is obtained by calculating the difference between the optical path lengths of the real wave front and the reference sphere. The general relations for calculated dependence of the wave-front aberration on the radius of the reference sphere are given.

  19. Contribution of the cornea and internal surfaces to the change of ocular aberrations with age

    NASA Astrophysics Data System (ADS)

    Artal, Pablo; Berrio, Esther; Guirao, Antonio; Piers, Patricia

    2002-01-01

    We studied the age dependence of the relative contributions of the aberrations of the cornea and the internal ocular surfaces to the total aberrations of the eye. We measured the wave-front aberration of the eye with a Hartmann-Shack sensor and the aberrations of the anterior corneal surface from the elevation data provided by a corneal topography system. The aberrations of the internal surfaces were obtained by direct subtraction of the ocular and corneal wave-front data. Measurements were obtained for normal healthy subjects with ages ranging from 20 to 70 years. The magnitude of the RMS wave-front aberration (excluding defocus and astigmatism) of the eye increases more than threefold within the age range considered. However, the aberrations of the anterior corneal surface increase only slightly with age. In most of the younger subjects, total ocular aberrations are lower than corneal aberrations, while in the older subjects the reverse condition occurs. Astigmatism, coma, and spherical aberration of the cornea are larger than in the complete eye in younger subjects, whereas the contrary is true for the older subjects. The internal ocular surfaces compensate, at least in part, for the aberrations associated with the cornea in most younger subjects, but this compensation is not present in the older subjects. These results suggest that the degradation of the ocular optics with age can be explained largely by the loss of the balance between the aberrations of the corneal and the internal surfaces.

  20. Persistence of Early Emerging Aberrant Behavior in Children with Developmental Disabilities

    ERIC Educational Resources Information Center

    Green, Vanessa A.; O'Reilly, Mark; Itchon, Jonathan; Sigafoos, Jeff

    2005-01-01

    This study examined the persistence of early emerging aberrant behavior in 13 preschool children with developmental disabilities. The severity of aberrant behavior was assessed every 6 months over a 3-year period. Teachers completed the assessments using the Aberrant Behavior Checklist [Aman, M. G., & Singh, N. N. (1986). "Aberrant…

  1. Adaptive electron beam shaping using a photoemission gun and spatial light modulator

    NASA Astrophysics Data System (ADS)

    Maxson, Jared; Lee, Hyeri; Bartnik, Adam C.; Kiefer, Jacob; Bazarov, Ivan

    2015-02-01

    The need for precisely defined beam shapes in photoelectron sources has been well established. In this paper, we use a spatial light modulator and simple shaping algorithm to create arbitrary, detailed transverse laser shapes with high fidelity. We transmit this shaped laser to the photocathode of a high voltage dc gun. Using beam currents where space charge is negligible, and using an imaging solenoid and fluorescent viewscreen, we show that the resultant beam shape preserves these detailed features with similar fidelity. Next, instead of transmitting a shaped laser profile, we use an active feedback on the unshaped electron beam image to create equally accurate and detailed shapes. We demonstrate that this electron beam feedback has the added advantage of correcting for electron optical aberrations, yielding shapes without skew. The method may serve to provide precisely defined electron beams for low current target experiments, space-charge dominated beam commissioning, as well as for online adaptive correction of photocathode quantum efficiency degradation.

  2. Electromagnetic Induction Aberration: The Possible Mechanism of Tic Douloureux

    PubMed Central

    2015-01-01

    A theory based on the principles of electromagnetic induction aberration is presented as the possible mechanism of classic trigeminal neuralgia, tic douloureux. The anatomy of the dorsal root entry zone of the trigeminal nerve at the pons in the proximity of the superior cerebellar artery presents a scenario conducive to the phenomenon of electromagnetic induction. When the action potentials traversing the axons in this zone of the compromised myelin come into juxtaposition with the vascular structure, the criteria for electromagnetic induction are satisfied. The laws of physics governing the phenomenon indicate that a new current, an aberration, would be produced. This could be responsible for the clinical symptoms of tic douloureux. Other clinical situations with similar features could share this mechanism. This proposed theory, a merger of anatomy, neurophysiology, and the physics of electromagnetic induction, extends the established concept of vascular compression as the etiology of tic douloureux. PMID:26180679

  3. Electromagnetic Induction Aberration: The Possible Mechanism of Tic Douloureux.

    PubMed

    Rish, Berkley

    2015-03-01

    A theory based on the principles of electromagnetic induction aberration is presented as the possible mechanism of classic trigeminal neuralgia, tic douloureux. The anatomy of the dorsal root entry zone of the trigeminal nerve at the pons in the proximity of the superior cerebellar artery presents a scenario conducive to the phenomenon of electromagnetic induction. When the action potentials traversing the axons in this zone of the compromised myelin come into juxtaposition with the vascular structure, the criteria for electromagnetic induction are satisfied. The laws of physics governing the phenomenon indicate that a new current, an aberration, would be produced. This could be responsible for the clinical symptoms of tic douloureux. Other clinical situations with similar features could share this mechanism. This proposed theory, a merger of anatomy, neurophysiology, and the physics of electromagnetic induction, extends the established concept of vascular compression as the etiology of tic douloureux.

  4. Aberrations and adaptive optics in super-resolution microscopy.

    PubMed

    Booth, Martin; Andrade, Débora; Burke, Daniel; Patton, Brian; Zurauskas, Mantas

    2015-08-01

    As one of the most powerful tools in the biological investigation of cellular structures and dynamic processes, fluorescence microscopy has undergone extraordinary developments in the past decades. The advent of super-resolution techniques has enabled fluorescence microscopy - or rather nanoscopy - to achieve nanoscale resolution in living specimens and unravelled the interior of cells with unprecedented detail. The methods employed in this expanding field of microscopy, however, are especially prone to the detrimental effects of optical aberrations. In this review, we discuss how super-resolution microscopy techniques based upon single-molecule switching, stimulated emission depletion and structured illumination each suffer from aberrations in different ways that are dependent upon intrinsic technical aspects. We discuss the use of adaptive optics as an effective means to overcome this problem.

  5. [239Pu and chromosomal aberrations in human peripheral blood lymphocytes].

    PubMed

    Okladnikova, N D; Osovets, S V; Kudriavtseva, T I

    2009-01-01

    The genome status in somatic cells was assessed using the chromosomal aberration (CA) test in peripheral blood lymphocytes from 194 plutonium workers exposed to occupational radiation mainly from low-transportable compounds of airborne 230Pu. Pu body burden at the time of cytogenetic study varied from values close to the method sensitivity to values multiply exceeding the permissible level. Standard (routine) methods of peripheral blood lymphocytes cultivation were applied. Chromatid- and chromosomal-type structural changes were estimated. Aberrations were estimated per 100 examined metaphase cells. The quantitative relationship between the CA frequency and Pu body burden and the absorbed dose to the lung was found. Mathematical processing of results was carried out based on the phenomenological model. The results were shown as theoretical and experimental curves. The threshold of the CA yield was 0.43 +/- 0.03 kBq (Pu body burden) and 6.12 +/- 1.20 cGy (absorbed dose to the lung).

  6. Aberrant hippocampal neurogenesis contributes to epilepsy and associated cognitive decline

    PubMed Central

    Cho, Kyung-Ok; Lybrand, Zane R.; Ito, Naoki; Brulet, Rebecca; Tafacory, Farrah; Zhang, Ling; Good, Levi; Ure, Kerstin; Kernie, Steven G.; Birnbaum, Shari G.; Scharfman, Helen E.; Eisch, Amelia J.; Hsieh, Jenny

    2015-01-01

    Acute seizures after a severe brain insult can often lead to epilepsy and cognitive impairment. Aberrant hippocampal neurogenesis follows the insult but the role of adult-generated neurons in the development of chronic seizures or associated cognitive deficits remains to be determined. Here we show that the ablation of adult neurogenesis before pilocarpine-induced acute seizures in mice leads to a reduction in chronic seizure frequency. We also show that ablation of neurogenesis normalizes epilepsy-associated cognitive deficits. Remarkably, the effect of ablating adult neurogenesis before acute seizures is long lasting as it suppresses chronic seizure frequency for nearly 1 year. These findings establish a key role of neurogenesis in chronic seizure development and associated memory impairment and suggest that targeting aberrant hippocampal neurogenesis may reduce recurrent seizures and restore cognitive function following a pro-epileptic brain insult. PMID:25808087

  7. Detection of epigenetic aberrations in the development of hepatocellular carcinoma.

    PubMed

    Zhang, Yujing

    2015-01-01

    Hepatocellular carcinoma (HCC) is the third most common cause of cancer death worldwide. Hepatocarcinogenesis is a complex, multistep process. It is now recognized that HCC is a both genetic and epigenetic disease; genetic and epigenetic components cooperate at all stages of hepatocarcinogenesis. Epigenetic changes involve aberrant DNA methylation, posttranslational histone modifications and aberrant expression of microRNAs all of which can affect the expression of oncogenes, tumor suppressor genes and other tumor-related genes and alter the pathways in cancer development. Several risk factors for HCC, including hepatitis B and C virus infections and exposure to the chemical carcinogen aflatoxin B1 have been found to influence epigenetic changes. Their interactions could play an important role in the initiation and progression of HCC. Discovery and detection of biomarkers for epigenetic changes is a promising area for early diagnosis and risk prediction of HCC.

  8. Functional annotation of rare gene aberration drivers of pancreatic cancer

    PubMed Central

    Tsang, Yiu Huen; Dogruluk, Turgut; Tedeschi, Philip M.; Wardwell-Ozgo, Joanna; Lu, Hengyu; Espitia, Maribel; Nair, Nikitha; Minelli, Rosalba; Chong, Zechen; Chen, Fengju; Chang, Qing Edward; Dennison, Jennifer B.; Dogruluk, Armel; Li, Min; Ying, Haoqiang; Bertino, Joseph R.; Gingras, Marie-Claude; Ittmann, Michael; Kerrigan, John; Chen, Ken; Creighton, Chad J.; Eterovic, Karina; Mills, Gordon B.; Scott, Kenneth L.

    2016-01-01

    As we enter the era of precision medicine, characterization of cancer genomes will directly influence therapeutic decisions in the clinic. Here we describe a platform enabling functionalization of rare gene mutations through their high-throughput construction, molecular barcoding and delivery to cancer models for in vivo tumour driver screens. We apply these technologies to identify oncogenic drivers of pancreatic ductal adenocarcinoma (PDAC). This approach reveals oncogenic activity for rare gene aberrations in genes including NAD Kinase (NADK), which regulates NADP(H) homeostasis and cellular redox state. We further validate mutant NADK, whose expression provides gain-of-function enzymatic activity leading to a reduction in cellular reactive oxygen species and tumorigenesis, and show that depletion of wild-type NADK in PDAC cell lines attenuates cancer cell growth in vitro and in vivo. These data indicate that annotating rare aberrations can reveal important cancer signalling pathways representing additional therapeutic targets. PMID:26806015

  9. Holographic optical system for aberration corrections in laser Doppler velocimetry

    NASA Technical Reports Server (NTRS)

    Kim, R. C.; Case, S. K.; Schock, H. J.

    1985-01-01

    An optical system containing multifaceted holographic optical elements (HOEs) has been developed to correct for aberrations introduced by nonflat windows in laser Doppler velocimetry. The multifacet aberration correction approach makes it possible to record on one plate many sets of adjacent HOEs that address different measurement volume locations. By using 5-mm-diameter facets, it is practical to place 10-20 sets of holograms on one 10 x 12.5-cm plate, so that the procedure of moving the entire optical system to examine different locations may not be necessary. The holograms are recorded in dichromated gelatin and therefore are nonabsorptive and suitable for use with high-power argon laser beams. Low f-number optics coupled with a 90-percent efficient distortion-correcting hologram in the collection side of the system yield high optical efficiency.

  10. Are aberrant phase transitions a driver of cellular aging?

    PubMed Central

    2016-01-01

    Why do cells age? Recent advances show that the cytoplasm is organized into many membrane‐less compartments via a process known as phase separation, which ensures spatiotemporal control over diffusion‐limited biochemical reactions. Although phase separation is a powerful mechanism to organize biochemical reactions, it comes with the trade‐off that it is extremely sensitive to changes in physical‐chemical parameters, such as protein concentration, pH, or cellular energy levels. Here, we highlight recent findings showing that age‐related neurodegenerative diseases are linked to aberrant phase transitions in neurons. We discuss how these aberrant phase transitions could be tied to a failure to maintain physiological physical‐chemical conditions. We generalize this idea to suggest that the process of cellular aging involves a progressive loss of the organization of phase‐separated compartments in the cytoplasm. PMID:27554449

  11. Evaluation of an automated karyotyping system for chromosome aberration analysis

    NASA Technical Reports Server (NTRS)

    Prichard, Howard M.

    1987-01-01

    Chromosome aberration analysis is a promising complement to conventional radiation dosimetry, particularly in the complex radiation fields encountered in the space environment. The capabilities of a recently developed automated karyotyping system were evaluated both to determine current capabilities and limitations and to suggest areas where future development should be emphasized. Cells exposed to radiometric chemicals and to photon and particulate radiation were evaluated by manual inspection and by automated karyotyping. It was demonstrated that the evaluated programs were appropriate for image digitization, storage, and transmission. However, automated and semi-automated scoring techniques must be advanced significantly if in-flight chromosome aberration analysis is to be practical. A degree of artificial intelligence may be necessary to realize this goal.

  12. Quantitative characterization of aberrations in x-ray optics

    NASA Astrophysics Data System (ADS)

    Seiboth, Frank; Kahnt, Maik; Scholz, Maria; Seyrich, Martin; Wittwer, Felix; Garrevoet, Jan; Falkenberg, Gerald; Schropp, Andreas; Schroer, Christian G.

    2016-09-01

    Due to the weak interaction of X-rays with matter and their small wavelength on the atomic scale, stringent requirements are put on X-ray optics manufacturing and metrology. As a result, these optics often suffer from aberrations. Until now, X-ray optics were mainly characterized by their focal spot size and efficiency. How- ever, both measures provide only insufficient information about optics quality. Here, we present a quantitative analysis of residual aberrations in current beryllium compound refractive lenses using ptychography followed by a determination of the wavefront error and subsequent Zernike polynomial decomposition. Known from visible light optics, we show that these measures can provide an adequate tool to determine and compare the quality of various X-ray optics.

  13. Hotspots of aberrant enhancer activity punctuate the colorectal cancer epigenome

    PubMed Central

    Cohen, Andrea J.; Saiakhova, Alina; Corradin, Olivia; Luppino, Jennifer M.; Lovrenert, Katreya; Bartels, Cynthia F.; Morrow, James J.; Mack, Stephen C.; Dhillon, Gursimran; Beard, Lydia; Myeroff, Lois; Kalady, Matthew F.; Willis, Joseph; Bradner, James E.; Keri, Ruth A.; Berger, Nathan A.; Pruett-Miller, Shondra M.; Markowitz, Sanford D.; Scacheri, Peter C.

    2017-01-01

    In addition to mutations in genes, aberrant enhancer element activity at non-coding regions of the genome is a key driver of tumorigenesis. Here, we perform epigenomic enhancer profiling of a cohort of more than forty genetically diverse human colorectal cancer (CRC) specimens. Using normal colonic crypt epithelium as a comparator, we identify enhancers with recurrently gained or lost activity across CRC specimens. Of the enhancers highly recurrently activated in CRC, most are constituents of super enhancers, are occupied by AP-1 and cohesin complex members, and originate from primed chromatin. Many activate known oncogenes, and CRC growth can be mitigated through pharmacologic inhibition or genome editing of these loci. Nearly half of all GWAS CRC risk loci co-localize to recurrently activated enhancers. These findings indicate that the CRC epigenome is defined by highly recurrent epigenetic alterations at enhancers which activate a common, aberrant transcriptional programme critical for CRC growth and survival. PMID:28169291

  14. Aberrant hippocampal neurogenesis contributes to epilepsy and associated cognitive decline.

    PubMed

    Cho, Kyung-Ok; Lybrand, Zane R; Ito, Naoki; Brulet, Rebecca; Tafacory, Farrah; Zhang, Ling; Good, Levi; Ure, Kerstin; Kernie, Steven G; Birnbaum, Shari G; Scharfman, Helen E; Eisch, Amelia J; Hsieh, Jenny

    2015-03-26

    Acute seizures after a severe brain insult can often lead to epilepsy and cognitive impairment. Aberrant hippocampal neurogenesis follows the insult but the role of adult-generated neurons in the development of chronic seizures or associated cognitive deficits remains to be determined. Here we show that the ablation of adult neurogenesis before pilocarpine-induced acute seizures in mice leads to a reduction in chronic seizure frequency. We also show that ablation of neurogenesis normalizes epilepsy-associated cognitive deficits. Remarkably, the effect of ablating adult neurogenesis before acute seizures is long lasting as it suppresses chronic seizure frequency for nearly 1 year. These findings establish a key role of neurogenesis in chronic seizure development and associated memory impairment and suggest that targeting aberrant hippocampal neurogenesis may reduce recurrent seizures and restore cognitive function following a pro-epileptic brain insult.

  15. Chromatic aberration control for tunable all-silicone membrane microlenses.

    PubMed

    Waibel, Philipp; Mader, Daniel; Liebetraut, Peter; Zappe, Hans; Seifert, Andreas

    2011-09-12

    Tunable multi-chamber microfluidic membrane microlenses with achromaticity over a given focal length range are demonstrated. In analogy to a fixed-focus achromatic doublet lens, the multi-lens system is based on a stack of microfluidic cavities filled with optically optimized liquids with precisely defined refractive index and Abbe number, and these are independently pneumatically actuated. The membranes separating the cavities form the refractive optical surfaces, and the curvatures as a function of pressure are calculated using a mechanical model for deformation of flexible plates. The results are combined with optical ray tracing simulations of the multi-lens system to yield chromatic aberration behavior, which is verified experimentally. A focal length tuning range of 5-40 mm and reduction in chromatic aberration of over 30% is demonstrated, limited by the availability of optical fluids.

  16. Telomere dysfunction drives aberrant hematopoietic differentiation and myelodysplastic syndrome.

    PubMed

    Colla, Simona; Ong, Derrick Sek Tong; Ogoti, Yamini; Marchesini, Matteo; Mistry, Nipun A; Clise-Dwyer, Karen; Ang, Sonny A; Storti, Paola; Viale, Andrea; Giuliani, Nicola; Ruisaard, Kathryn; Ganan Gomez, Irene; Bristow, Christopher A; Estecio, Marcos; Weksberg, David C; Ho, Yan Wing; Hu, Baoli; Genovese, Giannicola; Pettazzoni, Piergiorgio; Multani, Asha S; Jiang, Shan; Hua, Sujun; Ryan, Michael C; Carugo, Alessandro; Nezi, Luigi; Wei, Yue; Yang, Hui; D'Anca, Marianna; Zhang, Li; Gaddis, Sarah; Gong, Ting; Horner, James W; Heffernan, Timothy P; Jones, Philip; Cooper, Laurence J N; Liang, Han; Kantarjian, Hagop; Wang, Y Alan; Chin, Lynda; Bueso-Ramos, Carlos; Garcia-Manero, Guillermo; DePinho, Ronald A

    2015-05-11

    Myelodysplastic syndrome (MDS) risk correlates with advancing age, therapy-induced DNA damage, and/or shorter telomeres, but whether telomere erosion directly induces MDS is unknown. Here, we provide the genetic evidence that telomere dysfunction-induced DNA damage drives classical MDS phenotypes and alters common myeloid progenitor (CMP) differentiation by repressing the expression of mRNA splicing/processing genes, including SRSF2. RNA-seq analyses of telomere dysfunctional CMP identified aberrantly spliced transcripts linked to pathways relevant to MDS pathogenesis such as genome stability, DNA repair, chromatin remodeling, and histone modification, which are also enriched in mouse CMP haploinsufficient for SRSF2 and in CD34(+) CMML patient cells harboring SRSF2 mutation. Together, our studies establish an intimate link across telomere biology, aberrant RNA splicing, and myeloid progenitor differentiation.

  17. Method for identifying and quantifying nucleic acid sequence aberrations

    DOEpatents

    Lucas, J.N.; Straume, T.; Bogen, K.T.

    1998-07-21

    A method is disclosed for detecting nucleic acid sequence aberrations by detecting nucleic acid sequences having both a first and a second nucleic acid sequence type, the presence of the first and second sequence type on the same nucleic acid sequence indicating the presence of a nucleic acid sequence aberration. The method uses a first hybridization probe which includes a nucleic acid sequence that is complementary to a first sequence type and a first complexing agent capable of attaching to a second complexing agent and a second hybridization probe which includes a nucleic acid sequence that selectively hybridizes to the second nucleic acid sequence type over the first sequence type and includes a detectable marker for detecting the second hybridization probe. 11 figs.

  18. Method for identifying and quantifying nucleic acid sequence aberrations

    DOEpatents

    Lucas, Joe N.; Straume, Tore; Bogen, Kenneth T.

    1998-01-01

    A method for detecting nucleic acid sequence aberrations by detecting nucleic acid sequences having both a first and a second nucleic acid sequence type, the presence of the first and second sequence type on the same nucleic acid sequence indicating the presence of a nucleic acid sequence aberration. The method uses a first hybridization probe which includes a nucleic acid sequence that is complementary to a first sequence type and a first complexing agent capable of attaching to a second complexing agent and a second hybridization probe which includes a nucleic acid sequence that selectively hybridizes to the second nucleic acid sequence type over the first sequence type and includes a detectable marker for detecting the second hybridization probe.

  19. Filtering chromatic aberration for wide acceptance angle electrostatic lenses.

    PubMed

    Fazekas, Ádám; Tóth, László

    2014-07-01

    Chromatic aberration is a major issue for imaging mainly with large acceptance angle electrostatic lenses. Its correction is necessary to take advantage of the outstanding spatial and angular resolution that these lenses provide. We propose a method to eliminate the effect of chromatic aberration on the measured images by determining the impact resulting from higher and lower kinetic energies. Based on a spectral image sequence and a matrix, which describes the transmission function of the lens, a system of linear equations is solved to approximate the 2D spectral intensity distribution of the sample surface. We present the description of our method and preliminary test results, which show significant contrast and image quality improvement. The presented algorithm can also be applied as a software-based energy analyzer.

  20. Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes

    PubMed Central

    Biankin, Andrew V.; Waddell, Nicola; Kassahn, Karin S.; Gingras, Marie-Claude; Muthuswamy, Lakshmi B.; Johns, Amber L.; Miller, David K.; Wilson, Peter J.; Patch, Ann-Marie; Wu, Jianmin; Chang, David K.; Cowley, Mark J.; Gardiner, Brooke B.; Song, Sarah; Harliwong, Ivon; Idrisoglu, Senel; Nourse, Craig; Nourbakhsh, Ehsan; Manning, Suzanne; Wani, Shivangi; Gongora, Milena; Pajic, Marina; Scarlett, Christopher J.; Gill, Anthony J.; Pinho, Andreia V.; Rooman, Ilse; Anderson, Matthew; Holmes, Oliver; Leonard, Conrad; Taylor, Darrin; Wood, Scott; Xu, Qinying; Nones, Katia; Fink, J. Lynn; Christ, Angelika; Bruxner, Tim; Cloonan, Nicole; Kolle, Gabriel; Newell, Felicity; Pinese, Mark; Mead, R. Scott; Humphris, Jeremy L.; Kaplan, Warren; Jones, Marc D.; Colvin, Emily K.; Nagrial, Adnan M.; Humphrey, Emily S.; Chou, Angela; Chin, Venessa T.; Chantrill, Lorraine A.; Mawson, Amanda; Samra, Jaswinder S.; Kench, James G.; Lovell, Jessica A.; Daly, Roger J.; Merrett, Neil D.; Toon, Christopher; Epari, Krishna; Nguyen, Nam Q.; Barbour, Andrew; Zeps, Nikolajs; Kakkar, Nipun; Zhao, Fengmei; Wu, Yuan Qing; Wang, Min; Muzny, Donna M.; Fisher, William E.; Brunicardi, F. Charles; Hodges, Sally E.; Reid, Jeffrey G.; Drummond, Jennifer; Chang, Kyle; Han, Yi; Lewis, Lora R.; Dinh, Huyen; Buhay, Christian J.; Beck, Timothy; Timms, Lee; Sam, Michelle; Begley, Kimberly; Brown, Andrew; Pai, Deepa; Panchal, Ami; Buchner, Nicholas; De Borja, Richard; Denroche, Robert E.; Yung, Christina K.; Serra, Stefano; Onetto, Nicole; Mukhopadhyay, Debabrata; Tsao, Ming-Sound; Shaw, Patricia A.; Petersen, Gloria M.; Gallinger, Steven; Hruban, Ralph H.; Maitra, Anirban; Iacobuzio-Donahue, Christine A.; Schulick, Richard D.; Wolfgang, Christopher L.; Morgan, Richard A.; Lawlor, Rita T.; Capelli, Paola; Corbo, Vincenzo; Scardoni, Maria; Tortora, Giampaolo; Tempero, Margaret A.; Mann, Karen M.; Jenkins, Nancy A.; Perez-Mancera, Pedro A.; Adams, David J.; Largaespada, David A.; Wessels, Lodewyk F. A.; Rust, Alistair G.; Stein, Lincoln D.; Tuveson, David A.; Copeland, Neal G.; Musgrove, Elizabeth A.; Scarpa, Aldo; Eshleman, James R.; Hudson, Thomas J.; Sutherland, Robert L.; Wheeler, David A.; Pearson, John V.; McPherson, John D.; Gibbs, Richard A.; Grimmond, Sean M.

    2012-01-01

    Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis. PMID:23103869

  1. Chromosomal aberrations of cancer-testis antigens in myeloma patients.

    PubMed

    Curioni-Fontecedro, Alessandra; Martin, Vittoria; Vogetseder, Alexander; Knuth, Alexander; Moch, Holger; Soldini, Davide; Tinguely, Marianne

    2015-09-01

    Cancer-testis antigens (CTAgs) play a major role in the immune response against cancer, but their biological functions in germ and cancer cells is still unclear. MAGE-C1 and MAGE-C2 are two CTAgs located at the Xq27 region of chromosome X and frequently expressed in multiple myeloma. Chromosomal rearrangements often occur in myeloma. We therefore investigated whether numerical and structural chromosomal aberrations correlate with their protein expression in primary multiple myelomas. To this aim, we designed new fluorescence in situ hybridization probes specific for the MAGE region in the Xq27 region and evaluated simultaneously aberrations of the X chromosome centromere. The comparison of MAGE copy number and chromosome X status revealed that MAGE copy number changes occurred in 6/43 (14%) cases, independent of concomitant X chromosome alterations. These numerical aberrations are less frequent than the expression of MAGE-C1 and MAGE-C2 (63% and 27% of patients, respectively) and do not always correlate with MAGE-C1 and MAGE-C2 expressions, suggesting alternative regulatory mechanisms in the expression of these genes.

  2. Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes.

    PubMed

    Biankin, Andrew V; Waddell, Nicola; Kassahn, Karin S; Gingras, Marie-Claude; Muthuswamy, Lakshmi B; Johns, Amber L; Miller, David K; Wilson, Peter J; Patch, Ann-Marie; Wu, Jianmin; Chang, David K; Cowley, Mark J; Gardiner, Brooke B; Song, Sarah; Harliwong, Ivon; Idrisoglu, Senel; Nourse, Craig; Nourbakhsh, Ehsan; Manning, Suzanne; Wani, Shivangi; Gongora, Milena; Pajic, Marina; Scarlett, Christopher J; Gill, Anthony J; Pinho, Andreia V; Rooman, Ilse; Anderson, Matthew; Holmes, Oliver; Leonard, Conrad; Taylor, Darrin; Wood, Scott; Xu, Qinying; Nones, Katia; Fink, J Lynn; Christ, Angelika; Bruxner, Tim; Cloonan, Nicole; Kolle, Gabriel; Newell, Felicity; Pinese, Mark; Mead, R Scott; Humphris, Jeremy L; Kaplan, Warren; Jones, Marc D; Colvin, Emily K; Nagrial, Adnan M; Humphrey, Emily S; Chou, Angela; Chin, Venessa T; Chantrill, Lorraine A; Mawson, Amanda; Samra, Jaswinder S; Kench, James G; Lovell, Jessica A; Daly, Roger J; Merrett, Neil D; Toon, Christopher; Epari, Krishna; Nguyen, Nam Q; Barbour, Andrew; Zeps, Nikolajs; Kakkar, Nipun; Zhao, Fengmei; Wu, Yuan Qing; Wang, Min; Muzny, Donna M; Fisher, William E; Brunicardi, F Charles; Hodges, Sally E; Reid, Jeffrey G; Drummond, Jennifer; Chang, Kyle; Han, Yi; Lewis, Lora R; Dinh, Huyen; Buhay, Christian J; Beck, Timothy; Timms, Lee; Sam, Michelle; Begley, Kimberly; Brown, Andrew; Pai, Deepa; Panchal, Ami; Buchner, Nicholas; De Borja, Richard; Denroche, Robert E; Yung, Christina K; Serra, Stefano; Onetto, Nicole; Mukhopadhyay, Debabrata; Tsao, Ming-Sound; Shaw, Patricia A; Petersen, Gloria M; Gallinger, Steven; Hruban, Ralph H; Maitra, Anirban; Iacobuzio-Donahue, Christine A; Schulick, Richard D; Wolfgang, Christopher L; Morgan, Richard A; Lawlor, Rita T; Capelli, Paola; Corbo, Vincenzo; Scardoni, Maria; Tortora, Giampaolo; Tempero, Margaret A; Mann, Karen M; Jenkins, Nancy A; Perez-Mancera, Pedro A; Adams, David J; Largaespada, David A; Wessels, Lodewyk F A; Rust, Alistair G; Stein, Lincoln D; Tuveson, David A; Copeland, Neal G; Musgrove, Elizabeth A; Scarpa, Aldo; Eshleman, James R; Hudson, Thomas J; Sutherland, Robert L; Wheeler, David A; Pearson, John V; McPherson, John D; Gibbs, Richard A; Grimmond, Sean M

    2012-11-15

    Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis.

  3. Alignment induced aberration fields of next generation telescopes

    NASA Astrophysics Data System (ADS)

    Schmid, Tobias; Thompson, Kevin; Rolland, Jannick

    2008-08-01

    There is a long list of new ground-based optical telescopes being considered around the world. While many are conventional Cassegrain and Ritchey-Chretien designs, some are from a family of three mirror anastigmatic (TMA) telescopes that are configured with an offset field (but still obscured) that trace back to designs developed in the 1970s for military applications. The nodal theory of aberrations, developed in the late 1970s, provides valuable insights into the response of TMA telescopes to alignment errors. Here it is shown for the first time that the alignment limiting aberration in any TMA telescope is a 3rd order astigmatism term with a new field dependence, termed field-asymmetric, field-linear 3rd order astigmatism. It is also shown that a TMA telescope under assembly that is only measured to have excellent/perfect performance onaxis is not aligned in any significant way. This is because the new astigmatic term is always zero on-axis, even though it is large over the field of view. Knowledge of this intrinsic misalignment aberration field for any TMA telescope aids greatly in ensuring it can be aligned successfully. The James Webb Space Telescope (JWST), is used an example of a relevant TMA system.

  4. Genomic aberrations of BRCA1-mutated fallopian tube carcinomas.

    PubMed

    Hunter, Sally M; Ryland, Georgina L; Moss, Phillip; Gorringe, Kylie L; Campbell, Ian G

    2014-06-01

    Intraepithelial carcinomas of the fallopian tube are putative precursors to high-grade serous carcinomas of the ovary and peritoneum. Molecular characterization of these early precursors is limited but could be the key to identifying tumor biomarkers for early detection. This study presents a genome-wide copy number analysis of occult fallopian tube carcinomas identified through risk-reducing prophylactic oophorectomy from three women with germline BRCA1 mutations, demonstrating that extensive genomic aberrations are already established at this early stage. We found no indication of a difference in the level of genomic aberration observed in fallopian tube carcinomas compared with high-grade serous ovarian carcinomas. These findings suggest that spread to the peritoneal cavity may require no or very little further tumor evolution, which raises the question of what is the real window of opportunity to detect high-grade serous peritoneal carcinoma arising from the fallopian tube before it spreads. Nonetheless, the similarity of the genomic aberrations to those observed in high-grade serous ovarian carcinomas suggests that genetic biomarkers identified in late-stage disease may be relevant for early detection.

  5. Phase aberration correction by correlation in digital holographic adaptive optics

    PubMed Central

    Liu, Changgeng; Yu, Xiao; Kim, Myung K.

    2013-01-01

    We present a phase aberration correction method based on the correlation between the complex full-field and guide-star holograms in the context of digital holographic adaptive optics (DHAO). Removal of a global quadratic phase term before the correlation operation plays an important role in the correction. Correlation operation can remove the phase aberration at the entrance pupil plane and automatically refocus the corrected optical field. Except for the assumption that most aberrations lie at or close to the entrance pupil, the presented method does not impose any other constraints on the optical systems. Thus, it greatly enhances the flexibility of the optical design for DHAO systems in vision science and microscopy. Theoretical studies show that the previously proposed Fourier transform DHAO (FTDHAO) is just a special case of this general correction method, where the global quadratic phase term and a defocus term disappear. Hence, this correction method realizes the generalization of FTDHAO into arbitrary DHAO systems. The effectiveness and robustness of this method are demonstrated by simulations and experiments. PMID:23669707

  6. Chromosome aberrations in ataxia telangiectasia cells exposed to heavy ions

    NASA Astrophysics Data System (ADS)

    Kawata, T.; Cucinotta, F.; George, K.; Wu, H.; Shigematsu, N.; Furusawa, Y.; Uno, T.; Isobe, K.; Ito, H.

    Understanding of biological effects of heavy ions is important to assess healt h risk in space. One of the most important issues may be to take into account individual susceptibility. Ataxia telangiectasia (A-T) cells are known to exhibit abnormal responses to radiations but the mechanism of hyper radiosensitivity of A-T still remains unknown. We report chromosome aberrations in normal human fibroblasts and AT fibroblasts exposed to low- and high-LET radiations. A chemical-induced premature chromosome condensation (PCC) technique combined with chromosome- painting technique was applied to score chromosome aberrations in G2/M-phase cells. Following gamma irradiation, GM02052 cells were approximately 5 times more sensitive to g-rays than AG1522 cells. GM02052 cells had a much higher frequency of deletions and misrejoining than AG1522 cells. When the frequency of complex type aberrations was compared, GM02052 cells showed more than 10 times higher frequency than AG1522 cells. The results will be compared with those obtained from high-LET irradiations.

  7. Aberration correction for time-domain ultrasound diffraction tomography.

    PubMed

    Mast, T Douglas

    2002-07-01

    Extensions of a time-domain diffraction tomography method, which reconstructs spatially dependent sound speed variations from far-field time-domain acoustic scattering measurements, are presented and analyzed. The resulting reconstructions are quantitative images with applications including ultrasonic mammography, and can also be considered candidate solutions to the time-domain inverse scattering problem. Here, the linearized time-domain inverse scattering problem is shown to have no general solution for finite signal bandwidth. However, an approximate solution to the linearized problem is constructed using a simple delay-and-sum method analogous to "gold standard" ultrasonic beamforming. The form of this solution suggests that the full nonlinear inverse scattering problem can be approximated by applying appropriate angle- and space-dependent time shifts to the time-domain scattering data; this analogy leads to a general approach to aberration correction. Two related methods for aberration correction are presented: one in which delays are computed from estimates of the medium using an efficient straight-ray approximation, and one in which delays are applied directly to a time-dependent linearized reconstruction. Numerical results indicate that these correction methods achieve substantial quality improvements for imaging of large scatterers. The parametric range of applicability for the time-domain diffraction tomography method is increased by about a factor of 2 by aberration correction.

  8. Aberrant muscle syndrome: hypertrophy of the hand and arm due to aberrant muscles with or without hypertrophy of the muscles.

    PubMed

    Ogino, Toshihiko; Satake, Hiroshi; Takahara, Masatoshi; Kikuchi, Noriaki; Watanabe, Tadayosi; Iba, Kousuke; Ishii, Seiichi

    2010-06-01

    Five patients were reported in our congenital anomaly registry who had six hands in total with muscular hyperplasia, aberrant muscles, ulnar drift of the fingers in the metacarpophalangeal (MP) joints, flexion contractures of the MP joints, and enlargement of the metacarpal spaces. Thirty patients with unilateral involvement of this condition have been reported previously. We reviewed these cases and found that the condition varied in severity and that it was reported using different names. However, this condition seems different from true macrodactyly and multiple camptodactyly, including windblown hand, and seems to be an isolated entity of congenital upper limb anomaly. The authors recommend 'aberrant muscle syndrome' or 'accessory muscle syndrome' as a diagnostic name, because this seems to be the most common pathological finding in this condition.

  9. Statistical interpretation of the overdispersed distribution of radiation-induced dicentric chromosome aberrations at high LET

    SciTech Connect

    Virsik, R.P.; Harder, D.

    1981-01-01

    The hypothesis that overdispersion of the chromosome aberration number per cell results from multiple aberrations per particle traversal is investigated in mathematical terms. At a given absorbed dose, Poisson distributions are assumed both for the number of ionizing particles traversing a cell nucleus and for the number of aberrations induced by a single particle traversal. The resulting distribution of the number of aberrations per cell is the Neyman type A distribution, a special case of the generalized Poisson distribution. This function is generally overdispersed, its relative variance 1 + lambda being determined by the expectation value lambda of aberrations per particle traversal. Data from experiments with neutrons and ..cap alpha.. particles are found to agree with this theory. The developed formalism provides a method to determine the efficiency of aberration induction per particle traversal, lambda, from the frequency distribution of aberrations.

  10. The Hue of Shapes

    ERIC Educational Resources Information Center

    Albertazzi, Liliana; Da Pos, Osvaldo; Canal, Luisa; Micciolo, Rocco; Malfatti, Michela; Vescovi, Massimo

    2013-01-01

    This article presents an experimental study on the naturally biased association between shape and color. For each basic geometric shape studied, participants were asked to indicate the color perceived as most closely related to it, choosing from the Natural Color System Hue Circle. Results show that the choices of color for each shape were not…

  11. Demonstration of Current Profile Shaping using Double Dog-Leg Emittance Exchange Beam Line at Argonne Wakefield Accelerator

    SciTech Connect

    Ha, Gwanghui; Cho, Moo-Hyun; Conde, Manoel; Doran, Darrell; Gai, Wei; Jing, Chunguang; Kim, Kwang-Je; Liu, Wanming; Namkung, Won; Piot, Philippe; Power, John; Sun, Yin-E; Whiteford, Charles; Wisniewski, Eric; Zholents, Alexander

    2016-06-01

    Emittance exchange (EEX) based longitudinal current profile shaping is the one of the promising current profile shaping technique. This method can generate high quality arbitrary current profiles under the ideal conditions. The double dog-leg EEX beam line was recently installed at the Argonne Wakefield Accelerator (AWA) to explore the shaping capability and confirm the quality of this method. To demonstrate the arbitrary current profile generation, several different transverse masks are applied to generate different final current profiles. The phase space slopes and the charge of incoming beam are varied to observe and suppress the aberrations on the ideal profile. We present current profile shaping results, aberrations on the shaped profile, and its suppression.

  12. Local Solid Shape

    PubMed Central

    Koenderink, Jan; van Doorn, Andrea

    2015-01-01

    Local solid shape applies to the surface curvature of small surface patches—essentially regions of approximately constant curvatures—of volumetric objects that are smooth volumetric regions in Euclidean 3-space. This should be distinguished from local shape in pictorial space. The difference is categorical. Although local solid shape has naturally been explored in haptics, results in vision are not forthcoming. We describe a simple experiment in which observers judge shape quality and magnitude of cinematographic presentations. Without prior training, observers readily use continuous shape index and Casorati curvature scales with reasonable resolution. PMID:27648217

  13. General shape optimization capability

    NASA Technical Reports Server (NTRS)

    Chargin, Mladen K.; Raasch, Ingo; Bruns, Rudolf; Deuermeyer, Dawson

    1991-01-01

    A method is described for calculating shape sensitivities, within MSC/NASTRAN, in a simple manner without resort to external programs. The method uses natural design variables to define the shape changes in a given structure. Once the shape sensitivities are obtained, the shape optimization process is carried out in a manner similar to property optimization processes. The capability of this method is illustrated by two examples: the shape optimization of a cantilever beam with holes, loaded by a point load at the free end (with the shape of the holes and the thickness of the beam selected as the design variables), and the shape optimization of a connecting rod subjected to several different loading and boundary conditions.

  14. Aberration-Coreected Electron Microscopy at Brookhaven National Laboratory

    SciTech Connect

    Zhu,Y.; Wall, J.

    2008-04-01

    The last decade witnessed the rapid development and implementation of aberration correction in electron optics, realizing a more-than-70-year-old dream of aberration-free electron microscopy with a spatial resolution below one angstrom [1-9]. With sophisticated aberration correctors, modern electron microscopes now can reveal local structural information unavailable with neutrons and x-rays, such as the local arrangement of atoms, order/disorder, electronic inhomogeneity, bonding states, spin configuration, quantum confinement, and symmetry breaking [10-17]. Aberration correction through multipole-based correctors, as well as the associated improved stability in accelerating voltage, lens supplies, and goniometers in electron microscopes now enables medium-voltage (200-300kV) microscopes to achieve image resolution at or below 0.1nm. Aberration correction not only improves the instrument's spatial resolution but, equally importantly, allows larger objective lens pole-piece gaps to be employed thus realizing the potential of the instrument as a nanoscale property-measurement tool. That is, while retaining high spatial resolution, we can use various sample stages to observe the materials response under various temperature, electric- and magnetic- fields, and atmospheric environments. Such capabilities afford tremendous opportunities to tackle challenging science and technology issues in physics, chemistry, materials science, and biology. The research goal of the electron microscopy group at the Dept. of Condensed Matter Physics and Materials Science and the Center for Functional Nanomaterials, as well as the Institute for Advanced Electron Microscopy, Brookhaven National Laboratory (BNL), is to elucidate the microscopic origin of the physical- and chemical-behavior of materials, and the role of individual, or groups of atoms, especially in their native functional environments. We plan to accomplish this by developing and implementing various quantitative electron

  15. Phase aberration simulation study of MRgFUS breast treatments

    PubMed Central

    Farrer, Alexis I.; Almquist, Scott; Dillon, Christopher R.; Neumayer, Leigh A.; Parker, Dennis L.; Christensen, Douglas A.; Payne, Allison

    2016-01-01

    Purpose: This simulation study evaluates the effects of phase aberration in breast MR-guided focused ultrasound (MRgFUS) ablation treatments performed with a phased-array transducer positioned laterally to the breast. A quantification of these effects in terms of thermal dose delivery and the potential benefits of phase correction is demonstrated in four heterogeneous breast numerical models. Methods: To evaluate the effects of varying breast tissue properties on the quality of the focus, four female volunteers with confirmed benign fibroadenomas were imaged using 3T MRI. These images were segmented into numerical models with six tissue types, with each tissue type assigned standard acoustic properties from the literature. Simulations for a single-plane 16-point raster-scan treatment trajectory centered in a fibroadenoma in each modeled breast were performed for a breast-specific MRgFUS system. At each of the 16 points, pressure patterns both with and without applying a phase correction technique were determined with the hybrid-angular spectrum method. Corrected phase patterns were obtained using a simulation-based phase aberration correction technique to adjust each element’s transmit phase to obtain maximized constructive interference at the desired focus. Thermal simulations were performed for both the corrected and uncorrected pressure patterns using a finite-difference implementation of the Pennes bioheat equation. The effect of phase correction was evaluated through comparison of thermal dose accumulation both within and outside a defined treatment volume. Treatment results using corrected and uncorrected phase aberration simulations were compared by evaluating the power required to achieve a 20 °C temperature rise at the first treatment location. The extent of the volumes that received a minimum thermal dose of 240 CEM at 43 °C inside the intended treatment volume as well as the volume in the remaining breast tissues was also evaluated in the form of

  16. Anterior corneal and internal contributions to peripheral aberrations of human eyes

    NASA Astrophysics Data System (ADS)

    Atchison, David A.

    2004-03-01

    Anterior corneal and internal component contributions to overall peripheral aberrations of five human eyes were determined, based on corneal topography and overall aberration measurements. Anterior corneal position and orientation (tilt) were referenced to the line of sight. Ray tracing was performed through the anterior cornea for 6-mm-diameter pupils at angles out to 40° in both the temporal and the nasal visual fields. In general, both component and overall Zernike aberrations were greater for the nasal than for the temporal visual field. In general, the anterior corneal aberration components were considerably higher than the overall aberrations across the visual field and were balanced to a considerable degree by the internal ocular aberration components. The component and overall levels of Zernike third-order aberrations showed linear trends away from the fixation axis, and the component levels of Zernike fourth-order aberrations showed quadratic trends away from the fixation axis. The second-order, but not higher-order, aberration components were susceptible to the choice of image radius of curvature, while disregarding corneal position and orientation affected second- and higher-order aberration components.

  17. Wide-field aberration corrector for spherical gossamer primary mirrors

    NASA Astrophysics Data System (ADS)

    Beach, David A.

    2000-10-01

    If gossamer primary mirrors were to be constructed in a spherical form, it would be possible to arrange a simple null- test in situ. However, spherical mirrors would require correction of the large amount of spherical aberration created in pupils that generally will be greater than 2 m diameter. The design requirement is for diffraction-limited performance over a useful angular field. The otherwise excellent wide- field design solutions of the classical Schmidt and Maksutov are inapplicable in gossamer structures because of the mass and size penalty of large refractive components. However, it is possible for this mode of correction to be achieved near the prime focus by means of pupil transfer optics that minify the large entrance pupil down to more acceptable dimensions. A problem with these solutions is constraint of field coverage due to pupil aberrations created by the large spherical aberration of the primary mirror. This leads the designer towards slower primaries and the penalty of larger, heavier structures. A solution is presented here for spherical primaries with speeds up to f/4. This is based on the 'KiwiStar' principle presented here in 1997, in which a large spherical catoptric is combined by pupil-transfer with a smaller spherical catadioptric to give well corrected wide field images of high speed. This system is well suited to correction at the prime focus of large spherical mirrors, and has only one relatively small weak aspheric surface to provide zonal correction, all other surfaces being spherical. An example is presented of a 4 m diameter, f/2.5 system that is diffraction-limited over the whole of a 0.25 degree field (43 mm diameter), for a bandpass of 486 - 850 nm.

  18. Aberrant promoter hypermethylation in serum DNA from patients with silicosis.

    PubMed

    Umemura, Shigeki; Fujimoto, Nobukazu; Hiraki, Akio; Gemba, Kenichi; Takigawa, Nagio; Fujiwara, Keiichi; Fujii, Masanori; Umemura, Hiroshi; Satoh, Mamoru; Tabata, Masahiro; Ueoka, Hiroshi; Kiura, Katsuyuki; Kishimoto, Takumi; Tanimoto, Mitsune

    2008-09-01

    It is well established that patients with silicosis are at high risk for lung cancer; however, it is difficult to detect lung cancer by chest radiography during follow-up treatment of patients with silicosis because of preexisting diffuse pulmonary shadows. The purpose of this study is to evaluate the usefulness of detection of serum DNA methylation for early detection of lung cancer in silicosis. Serum samples from healthy controls (n = 20) and silicosis patients with (n = 11) and without (n = 67) lung cancer were tested for aberrant hypermethylation at the promoters of the DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT), p16(INK4a), ras association domain family 1A (RASSF1A), the apoptosis-related gene death-associated protein kinase (DAPK) and retinoic acid receptor beta (RARbeta) by methylation-specific polymerase chain reaction. Aberrant promoter methylation in at least one of five tumor suppressor genes was detected more frequently in the serum DNA of silicosis patients with lung cancer than in that of patients without it (P = 0.006). Furthermore, the odds ratio of having lung cancer was 9.77 (P = 0.009) for those silicosis patients with methylation of at least one gene. Extended exposure to silica (>30 years) was correlated with an increased methylation frequency (P = 0.017); however, methylation status did not correlate with age, smoking history or radiographic findings of silicosis. These results suggest that testing for aberrant promoter methylation of tumor suppressor genes using serum DNA may facilitate early detection of lung cancer in patients with silicosis.

  19. Intrinsic instability of aberration-corrected electron microscopes.

    PubMed

    Schramm, S M; van der Molen, S J; Tromp, R M

    2012-10-19

    Aberration-corrected microscopes with subatomic resolution will impact broad areas of science and technology. However, the experimentally observed lifetime of the corrected state is just a few minutes. Here we show that the corrected state is intrinsically unstable; the higher its quality, the more unstable it is. Analyzing the contrast transfer function near optimum correction, we define an "instability budget" which allows a rational trade-off between resolution and stability. Unless control systems are developed to overcome these challenges, intrinsic instability poses a fundamental limit to the resolution practically achievable in the electron microscope.

  20. FISH and FICTION to detect chromosomal aberrations in lymphomas.

    PubMed

    Giefing, Maciej; Siebert, Reiner

    2013-01-01

    Fluorescence In Situ Hybridization (FISH) is a powerful and robust technique allowing the visualization of target sequences like genes in interphase nuclei. It is widely used in routine diagnostics to identify cancer specific aberrations including lymphoma associated translocations or gene copy number changes in single tumor cells. By combining FISH with immunophenotyping-a technique called Fluorescence Immunophenotyping and Interphase Cytogenetic as a Tool for Investigation Of Neoplasia (FICTION)-it is moreover possible to identify a cell population of interest. Here we describe standard protocols for FISH and FICTION as used in our laboratory in diagnosis and research.

  1. Correcting for Beam Aberrations in a Beam-Waveguide Antenna

    NASA Technical Reports Server (NTRS)

    Franco, Manuel; Slobin, Stephen; Veruttipong, Watt

    2003-01-01

    A method for correcting the aim of a beam-waveguide microwave antenna compensates for the beam aberration that occurs during radio tracking of a target that has a component of velocity transverse to the line of sight from the tracking station. The method was devised primarily for use in tracking of distant target spacecraft by large terrestrial beam-waveguide antennas of NASA's Deep Space Network (DSN). The method should also be adaptable to tracking, by other beam-waveguide antennas, of targets that move with large transverse velocities at large distances from the antennas.

  2. Active Correction of Aberrations of Low-Quality Telescope Optics

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Chen, Yijian

    2007-01-01

    A system of active optics that includes a wavefront sensor and a deformable mirror has been demonstrated to be an effective means of partly correcting wavefront aberrations introduced by fixed optics (lenses and mirrors) in telescopes. It is envisioned that after further development, active optics would be used to reduce wavefront aberrations of about one wave or less in telescopes having aperture diameters of the order of meters or tens of meters. Although this remaining amount of aberration would be considered excessive in scientific applications in which diffraction-limited performance is required, it would be acceptable for free-space optical- communication applications at wavelengths of the order of 1 m. To prevent misunderstanding, it is important to state the following: The technological discipline of active optics, in which the primary or secondary mirror of a telescope is directly and dynamically tilted, distorted, and/or otherwise varied to reduce wavefront aberrations, has existed for decades. The term active optics does not necessarily mean the same thing as does adaptive optics, even though active optics and adaptive optics are related. The term "adaptive optics" is often used to refer to wavefront correction at speeds characterized by frequencies ranging up to between hundreds of hertz and several kilohertz high enough to enable mitigation of adverse effects of fluctuations in atmospheric refraction upon propagation of light beams. The term active optics usually appears in reference to wavefront correction at significantly lower speeds, characterized by times ranging from about 1 second to as long as minutes. Hence, the novelty of the present development lies, not in the basic concept of active or adaptive optics, but in the envisioned application of active optics in conjunction with a deformable mirror to achieve acceptably small wavefront errors in free-space optical communication systems that include multi-meter-diameter telescope mirrors that are

  3. Coherence and aberration effects in surface plasmon polariton imaging.

    PubMed

    Berthel, Martin; Jiang, Quanbo; Chartrand, Camille; Bellessa, Joel; Huant, Serge; Genet, Cyriaque; Drezet, Aurélien

    2015-09-01

    We study theoretically and experimentally coherent imaging of surface plasmon polaritons using either leakage radiation microscopy through a thin metal film or interference microscopy through a thick metal film. Using a rigorous modal formalism based on scalar Whittaker potentials, we develop a systematic analytical and vectorial method adapted to the analysis of coherent imaging involving surface plasmon polaritons. The study includes geometrical aberrations due index mismatch which played an important role in the interpretation of recent experiments using leakage radiation microscopy. We compare our theory with experiments using classical or quantum near-field scanning optical microscopy probes and show that the approach leads to a full interpretation of the recorded optical images.

  4. Coherence and aberration effects in surface plasmon polariton imaging

    NASA Astrophysics Data System (ADS)

    Berthel, Martin; Jiang, Quanbo; Chartrand, Camille; Bellessa, Joel; Huant, Serge; Genet, Cyriaque; Drezet, Aurélien

    2015-09-01

    We study theoretically and experimentally coherent imaging of surface plasmon polaritons using either leakage radiation microscopy through a thin metal film or interference microscopy through a thick metal film. Using a rigorous modal formalism based on scalar Whittaker potentials, we develop a systematic analytical and vectorial method adapted to the analysis of coherent imaging involving surface plasmon polaritons. The study includes geometrical aberrations due index mismatch which played an important role in the interpretation of recent experiments using leakage radiation microscopy. We compare our theory with experiments using classical or quantum near-field scanning optical microscopy probes and show that the approach leads to a full interpretation of the recorded optical images.

  5. Adaptive dispersion formula for index interpolation and chromatic aberration correction.

    PubMed

    Li, Chia-Ling; Sasián, José

    2014-01-13

    This paper defines and discusses a glass dispersion formula that is adaptive. The formula exhibits superior convergence with a minimum number of coefficients. Using this formula we rationalize the correction of chromatic aberration per spectrum order. We compare the formula with the Sellmeier and Buchdahl formulas for glasses in the Schott catalogue. The six coefficient adaptive formula is found to be the most accurate with an average maximum index of refraction error of 2.91 × 10(-6) within the visible band.

  6. Removing lateral chromatic aberration in bright field optical microscopy.

    PubMed

    Guzmán-Altamirano, Miguel; Gutiérrez-Medina, Braulio

    2015-06-01

    We present an efficient alternative to remove lateral chromatic aberration (LCA) in bright field light microscopy images. Our procedure is based on error calibration using time-sequential acquisition at different wavelengths, and error correction through digital image warping. Measurement of the displacements of fiducial marks in the red and green images relative to blue provide calibration factors that are subsequently used in test images to realign color channels digitally. We demonstrate quantitative improvement in the position and boundaries of objects in target slides and in the color content and morphology of specimens in stained biological samples. Our results show a reduction of LCA content below the 0.1% level.

  7. Miniaturized modules for light sheet microscopy with low chromatic aberration.

    PubMed

    Bruns, T; Bauer, M; Bruns, S; Meyer, H; Kubin, D; Schneckenburger, H

    2016-12-01

    Two miniaturized fibre-coupled modules for light sheet-based microscopy are described and compared with respect to image quality, chromatic aberration and beam alignment. Whereas in one module the light sheet is created by an achromatic cylindrical lens, reflection by a spherical mirror and concomitant astigmatic distortion are used to create the light sheet in the second module. Test experiments with fluorescent dyes in solution and multicellular tumour spheroids are reported, and some details on construction are given for both systems. Both modules are optimized for imaging individual cell layers of 3D biological samples and can be adapted to fit commercial microscopes.

  8. Intrinsic Instability of Aberration-Corrected Electron Microscopes

    NASA Astrophysics Data System (ADS)

    Schramm, S. M.; van der Molen, S. J.; Tromp, R. M.

    2012-10-01

    Aberration-corrected microscopes with subatomic resolution will impact broad areas of science and technology. However, the experimentally observed lifetime of the corrected state is just a few minutes. Here we show that the corrected state is intrinsically unstable; the higher its quality, the more unstable it is. Analyzing the contrast transfer function near optimum correction, we define an “instability budget” which allows a rational trade-off between resolution and stability. Unless control systems are developed to overcome these challenges, intrinsic instability poses a fundamental limit to the resolution practically achievable in the electron microscope.

  9. [The aberrant parasitism of horse botflies (Diptera: Gasterophilidae)].

    PubMed

    Rastegaev, Iu M

    1990-01-01

    Alongside with a high intensity of infection of horses with botfly larvae there was observed mass aberrant parasitism of horse botflies in farms of Astrakhan, Guryev and Uralsk Provinces, and in the Kalmyk ASSR in 1980-1981 and 1987. As a result of extremely high aggregation of horse botfly larvae in their usual localization places, Gasterophilus pecorum larvae remained, due to interspecific competition, in nonspecific places (oral cavity, pharynx), adapted to new habitats and normally developed. Their number varied from 260 to 750 specimens. Localization of G. pecorum larvae in the mentioned departments of the alimentary canal results in serious morbidity of horses.

  10. Three-dimensional polarization aberration functions in optical system based on three-dimensional polarization ray-tracing calculus

    NASA Astrophysics Data System (ADS)

    He, Wenjun; Fu, Yuegang; Liu, Zhiying; Zhang, Lei; Wang, Jiake; Zheng, Yang; Li, Yahong

    2017-03-01

    The polarization aberrations of a complex optical system with multi-element lens have been investigated using a 3D polarization aberration function. The 3D polarization ray-tracing matrix has been combined with the optical path difference to obtain a 3D polarization aberration function, which avoids the need for a complicated phase unwrapping process. The polarization aberrations of a microscope objective have been analyzed to include, the distributions of 3D polarization aberration functions, diattenuation aberration, retardance aberration, and polarization-dependent intensity on the exit pupil. Further, the aberrations created by the field of view and the coating on the distribution rules of 3D polarization aberration functions are discussed in detail. Finally a novel appropriate field of view and wavelength correction is proposed for a polarization aberration function which optimizes the image quality of a multi-element optical system.

  11. Weak correlation between the aberration dynamics of the human eye and the cardiopulmonary system

    NASA Astrophysics Data System (ADS)

    Hampson, Karen M.; Munro, Ian; Paterson, Carl; Dainty, Christopher

    2005-07-01

    It is fairly well established that the higher-order aberrations of the eye fluctuate over relatively short time periods, but as yet there is no conclusive evidence regarding the origin of these fluctuations. We measured the aberrations and the pulse pressure wave simultaneously for five subjects. The aberrations were measured by using a Shack-Hartmann sensor sampling at 21.2 Hz. We decomposed the aberration data into Zernike coefficients up to and including fifth order and also calculated the rms wave-front error. From the pulse data the heart rate variability signal was also derived. Coherence function analysis showed that for all subjects there was a weak correlation between many of the aberrations and the pulse and the derived heart rate variability. The pulse and the heart rate variability can account for only 11%+/-2% and 20%+/-2%, respectively, of the aberration dynamics.

  12. Performance of Dispersed Fringe Sensor in the Presence of Segmented Mirror Aberrations - Modeling and Simulations

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Basinger, Scott A.; Redding, David C.

    2006-01-01

    Wavefront aberrations will lower the DFS fringe visibility and DFS signal SNR. The specific effect of wavefront aberration on DFS depends on the aberration type. Due to the "pixel spatial filter" effect the extracted DFS signal can tolerate moderate amount of wavefront aberrations..By averaging piston detection results from multiple traces extracted from fringe images DFS can further increase its robustness against wavefront aberration. Line-of-sight jitter can cause significant loss of fringe visibility will affect more on the aberrated system..Modeling results have shown that gravity sag on the JWST segment mirror during I&T will lower the DHS fringe visibility by factor of 2-3X and lower the DHS signal intensity by factor of approx.5X. Under gravity sag the RMS DHS detection error approx. 100 nm.

  13. Analytical analysis for impact of polarization aberration of projection lens on lithographic imaging quality

    NASA Astrophysics Data System (ADS)

    Shen, Lina; Li, Sikun; Wang, Xiangzhao; Yan, Guanyong

    2015-03-01

    In high-NA and hyper-NA lithography systems, the polarization aberration of projection lens leads to imaging degradations. Typically, numerical simulations are used to explore the relationship. In this paper, analytical analysis for the impact of polarization aberration of projection lens on the aerial image of alternating phase-shift mask (Alt-PSM) is realized. The analytical expressions of image placement error (IPE) and best focus shift (BFS) caused by polarization aberration are derived from the intensity of aerial image. The derived expressions match simulation results extremely well, and can be used to understand more fully the detrimental impact of polarization aberration on lithographic imaging quality. The linear relationships between IPE and odd items of Pauli-Zernike polarization aberrations, as well as that between BFS and even items of Pauli-Zernike polarization aberrations are established, using linear polarization illumination. The accuracy of the linear relationships is assessed by the least square method.

  14. Study of cenesthesias and body image aberration in schizophrenia

    PubMed Central

    Rajender, Gaurav; Kanwal, Krishna; Rathore, Dinesh M.; Chaudhary, Deepa

    2009-01-01

    Background: Abnormal body sensations are reported frequently by schizophrenic patients. Cenesthesias are infrequently recognized and diagnosis of cenesthopathic schizophrenia is rarely made. There are very few studies regarding the same. Aims and Objectives: To assess cenesthesias and different aspects of body image aberration and their relationship with psychopathology in patients with paranoid schizophrenia. Materials and Methods: Seventy patients of paranoid schizophrenia meeting the inclusion and exclusion criteria were assessed with Positive and Negative Symptom Scale(PANSS) for psychopathology, Bonn Scale for Assessment of Basic Symptoms/Category D ‘Cenesthesias’ (BSABS), Image-Marking Procedure(IMP), alteration of body size and body cathexis. Assessments were made at baseline and after two weeks and assessed with SPSS 12.0. Results: The most commonly endorsed items on BSABS were depersonalization, motor weakness, abnormal pain, numbness and stiffness. Patients underestimated lower extremities and feelings of body size change which was positively correlated with PANSS-scores and improved on reassessment. Cenesthesias were positively correlated with disturbances of body concept and were present at onset in 40% and change form in 75.7%. Conclusions: Cenesthesias and body image aberrations are common in paranoid schizophrenia. They are present from onset in few, change form and improve on treatment. Cenesthesias and disturbances of body concept are correlated and body size is associated with other psychopathology. PMID:19881047

  15. Biclonal chromosomal aberrations in a child with myelodysplastic syndrome.

    PubMed

    Jakab, Z; Balogh, E; Kiss, C; Pajor, L; Oláh, E

    1999-01-01

    Hematological malignancies and premalignant diseases are generally of monoclonal origin. The prognostic and therapeutic significance of finding two genetically independent clones remains to be determined. We followed a case of childhood myelodysplastic syndrome showing biclonal chromosomal abnormalities (+8, -7) by conventional cytogenetic examination and double target fluorescence in situ hybridization (FISH). A 7-year-old girl presented with Plaut-Vincent angina and leukopenia. The cytogenetic aberration of +8 was the first sign to suggest MDS. Serial bone marrow controls, prompted by a progressive clinical course detected myelodysplastic changes and a new clonal aberration (-7). The presence of -7 and +8 in two independent clones was verified by double-target FISH. While at diagnosis and during cytokine treatment more cells showed +8, after successful all-trans retinoic acid (ATRA) therapy, the clone with -7 predominated. Following allogeneic bone marrow transplantation the patient displayed donor-derived hematopoesis. Our data stress the significance of cytogenetic and FISH examinations in detecting specific genetic abnormalities and progressive clonal changes as an indicator and guideline for therapy. Different cell clones characterized by different genetic changes might be associated with different biologic features reflected in their response to treatment.

  16. Exercise protects against methamphetamine-induced aberrant neurogenesis.

    PubMed

    Park, Minseon; Levine, Harry; Toborek, Michal

    2016-09-28

    While no effective therapy is available for the treatment of methamphetamine (METH)-induced neurotoxicity, aerobic exercise is being proposed to improve depressive symptoms and substance abuse outcomes. The present study focuses on the effect of exercise on METH-induced aberrant neurogenesis in the hippocampal dentate gyrus in the context of the blood-brain barrier (BBB) pathology. Mice were administered with METH or saline by i.p. injections for 5 days with an escalating dose regimen. One set of mice was sacrificed 24 h post last injection of METH, and the remaining animals were either subjected to voluntary wheel running (exercised mice) or remained in sedentary housing (sedentary mice). METH administration decreased expression of tight junction (TJ) proteins and increased BBB permeability in the hippocampus. These changes were preserved post METH administration in sedentary mice and were associated with the development of significant aberrations of neural differentiation. Exercise protected against these effects by enhancing the protein expression of TJ proteins, stabilizing the BBB integrity, and enhancing the neural differentiation. In addition, exercise protected against METH-induced systemic increase in inflammatory cytokine levels. These results suggest that exercise can attenuate METH-induced neurotoxicity by protecting against the BBB disruption and related microenvironmental changes in the hippocampus.

  17. Mechanistic modeling of aberrant energy metabolism in human disease

    PubMed Central

    Sangar, Vineet; Eddy, James A.; Simeonidis, Evangelos; Price, Nathan D.

    2012-01-01

    Dysfunction in energy metabolism—including in pathways localized to the mitochondria—has been implicated in the pathogenesis of a wide array of disorders, ranging from cancer to neurodegenerative diseases to type II diabetes. The inherent complexities of energy and mitochondrial metabolism present a significant obstacle in the effort to understand the role that these molecular processes play in the development of disease. To help unravel these complexities, systems biology methods have been applied to develop an array of computational metabolic models, ranging from mitochondria-specific processes to genome-scale cellular networks. These constraint-based (CB) models can efficiently simulate aspects of normal and aberrant metabolism in various genetic and environmental conditions. Development of these models leverages—and also provides a powerful means to integrate and interpret—information from a wide range of sources including genomics, proteomics, metabolomics, and enzyme kinetics. Here, we review a variety of mechanistic modeling studies that explore metabolic functions, deficiency disorders, and aberrant biochemical pathways in mitochondria and related regions in the cell. PMID:23112774

  18. Exaggerated translation causes synaptic and behavioural aberrations associated with autism.

    PubMed

    Santini, Emanuela; Huynh, Thu N; MacAskill, Andrew F; Carter, Adam G; Pierre, Philippe; Ruggero, Davide; Kaphzan, Hanoch; Klann, Eric

    2013-01-17

    Autism spectrum disorders (ASDs) are an early onset, heterogeneous group of heritable neuropsychiatric disorders with symptoms that include deficits in social interaction skills, impaired communication abilities, and ritualistic-like repetitive behaviours. One of the hypotheses for a common molecular mechanism underlying ASDs is altered translational control resulting in exaggerated protein synthesis. Genetic variants in chromosome 4q, which contains the EIF4E locus, have been described in patients with autism. Importantly, a rare single nucleotide polymorphism has been identified in autism that is associated with increased promoter activity in the EIF4E gene. Here we show that genetically increasing the levels of eukaryotic translation initiation factor 4E (eIF4E) in mice results in exaggerated cap-dependent translation and aberrant behaviours reminiscent of autism, including repetitive and perseverative behaviours and social interaction deficits. Moreover, these autistic-like behaviours are accompanied by synaptic pathophysiology in the medial prefrontal cortex, striatum and hippocampus. The autistic-like behaviours displayed by the eIF4E-transgenic mice are corrected by intracerebroventricular infusions of the cap-dependent translation inhibitor 4EGI-1. Our findings demonstrate a causal relationship between exaggerated cap-dependent translation, synaptic dysfunction and aberrant behaviours associated with autism.

  19. HER2 aberrations in cancer: implications for therapy.

    PubMed

    Yan, Min; Parker, Barbara A; Schwab, Richard; Kurzrock, Razelle

    2014-07-01

    Although anti-HER2 (human epidermal growth factor receptor 2) therapy is currently approved for breast, gastric, and gastroesophageal cancers overexpressing the HER2 protein or amplified for the HER2 gene, HER2 aberrations (gene amplification, gene mutations, and protein overexpression) are reported in other diverse malignancies. Indeed, about 1-37% of tumors of the following types harbor HER2 aberrations: bladder, cervix, colon, endometrium, germ cell, glioblastoma, head and neck, liver, lung, ovarian, pancreas, and salivary duct. Four HER2-targeted therapies have been approved for HER2-positive breast cancer: two antibodies (trastuzumab and pertuzumab), an antibody-drug conjugate (ado-trastuzumab emtansine), and a small molecule kinase inhibitor (lapatinib). In addition, afatinib, a small molecule kinase inhibitor that causes irreversible inhibition of EGFR (epidermal growth factor receptor) and HER2, was recently approved for EGFR-mutated non-small cell lung cancer. A large number of novel HER2-targeted agents are also in clinical trials. Herein we discuss the state of the art in understanding and targeting HER2 across anatomic tumor types.

  20. Aberrant functional brain connectome in people with antisocial personality disorder

    PubMed Central

    Tang, Yan; Long, Jun; Wang, Wei; Liao, Jian; Xie, Hua; Zhao, Guihu; Zhang, Hao

    2016-01-01

    Antisocial personality disorder (ASPD) is characterised by a disregard for social obligations and callous unconcern for the feelings of others. Studies have demonstrated that ASPD is associated with abnormalities in brain regions and aberrant functional connectivity. In this paper, topological organisation was examined in resting-state fMRI data obtained from 32 ASPD patients and 32 non-ASPD controls. The frequency-dependent functional networks were constructed using wavelet-based correlations over 90 brain regions. The topology of the functional networks of ASPD subjects was analysed via graph theoretical analysis. Furthermore, the abnormal functional connectivity was determined with a network-based statistic (NBS) approach. Our results revealed that, compared with the controls, the ASPD patients exhibited altered topological configuration of the functional connectome in the frequency interval of 0.016–0.031 Hz, as indicated by the increased clustering coefficient and decreased betweenness centrality in the medial superior frontal gyrus, precentral gyrus, Rolandic operculum, superior parietal gyrus, angular gyrus, and middle temporal pole. In addition, the ASPD patients showed increased functional connectivity mainly located in the default-mode network. The present study reveals an aberrant topological organisation of the functional brain network in individuals with ASPD. Our findings provide novel insight into the neuropathological mechanisms of ASPD. PMID:27257047

  1. Exercise protects against methamphetamine-induced aberrant neurogenesis

    PubMed Central

    Park, Minseon; Levine, Harry; Toborek, Michal

    2016-01-01

    While no effective therapy is available for the treatment of methamphetamine (METH)-induced neurotoxicity, aerobic exercise is being proposed to improve depressive symptoms and substance abuse outcomes. The present study focuses on the effect of exercise on METH-induced aberrant neurogenesis in the hippocampal dentate gyrus in the context of the blood-brain barrier (BBB) pathology. Mice were administered with METH or saline by i.p. injections for 5 days with an escalating dose regimen. One set of mice was sacrificed 24 h post last injection of METH, and the remaining animals were either subjected to voluntary wheel running (exercised mice) or remained in sedentary housing (sedentary mice). METH administration decreased expression of tight junction (TJ) proteins and increased BBB permeability in the hippocampus. These changes were preserved post METH administration in sedentary mice and were associated with the development of significant aberrations of neural differentiation. Exercise protected against these effects by enhancing the protein expression of TJ proteins, stabilizing the BBB integrity, and enhancing the neural differentiation. In addition, exercise protected against METH-induced systemic increase in inflammatory cytokine levels. These results suggest that exercise can attenuate METH-induced neurotoxicity by protecting against the BBB disruption and related microenvironmental changes in the hippocampus. PMID:27677455

  2. Active optics concept for hypertelescope aberration control and pupil densification

    NASA Astrophysics Data System (ADS)

    Dohlen, Kjetil; Dargent, Pascal; Ferrari, Marc; Lemaitre, Gerard R.

    2003-02-01

    One of the instrumental concepts under study for large baseline interferometers for high resolution astronomical imaging, in particular applied to exoplanet search and characterisation, is the hypertelescope (HT). Mainly considered for space deployment, this sparse array of mirror segments supported either by a struss structure or by free-flying micro satellites form a giant, diluted primary mirror. The focal plane instrumentation, including pupil densification optics, is located in the primary focus instrument space craft (ISC). Baselines considered for first-generation HTs are of the order of 100 m, but one can envisage kilometric arrays capable of unprecedented angular resolution. Pointing with such a telescope poses orbital navigation problems. Letting the entire array perform a slow sky-scanning motion and navigating the ISC within the primary focal plane in order to follow the image of the object may solve these problems. The ISC must therefore be equipped with aberration correction optics capable of covering a sufficiently large primary field of view, of the order of a few degrees. In this paper we present optical and mechanical concepts for combined aberration correction and pupil densification using multimode deformable mirror (MDM) and mechanically amplified piezo actuator technologies. Among the advantages of such a system over large monolithic corrector optics is the relaxation of piston alignment requirements for primary segments.

  3. Velocity aberration and atmospheric refraction in satellite laser communication experiments.

    PubMed

    Nugent, L J; Condon, R J

    1966-11-01

    The effects of satellite velocity aberration and atmospheric refraction on the direction of propagation of lagser radiation reflected from a satellite back to an observer on the earth are examined. A velocity aberration analysis for the two-dimensional case where the satellite passes directly overhead at velocity v is presented to first order in v/c in order to illustrate the method. The equations for the more general threedimensional case are then given to first order in v/c, and it is indicated that higher order treatments are normally unnecessary in typical experimental considerations. Following this, a simple approximate equation giving the atmospheric refraction to an accuracy of a few microradians is developed; it is indicated that greater accuracy is not important because of laser pointing limitations imposed by atmospheric scattering and turbulence. The atmospheric refraction equation depends only on the apparent zenith angle of the satellite reflector relative to the earth-based laser, on the satelli-te altitude, and on the index of refraction of the laser radiation in the atmosphere at the earth's surface. Both of these developments should be useful in the design and interpretation of satellite laser-communication experiments.

  4. Aberrant DNA methylation imprints in aborted bovine clones.

    PubMed

    Liu, Jing-He; Yin, Shen; Xiong, Bo; Hou, Yi; Chen, Da-Yuan; Sun, Qing-Yuan

    2008-04-01

    Genomic imprinting plays a very important role during development and its abnormality may heavily undermine the developmental potential of bovine embryos. Because of limited resources of the cow genome, bovine genomic imprinting, both in normal development and in somatic cell nuclear transfer (SCNT) cloning, is not well documented. DNA methylation is thought to be a major factor for the establishment of genomic imprinting. In our study, we determined the methylation status of differential methylated regions (DMRs) of four imprinted genes in four spontaneously aborted SCNT-cloned fetuses (AF). Firstly, abnormal methylation imprints were observed in each individual to different extents. In particular, Peg3 and MAOA were either seriously demethylated or showed aberrant methylation patterns in four aborted clones we tested, but Xist and Peg10 exhibited relatively better maintained methylation status in AF1 and AF4. Secondly, two aborted fetuses, AF2 and AF3 exhibited severe aberrant methylation imprints of four imprinted genes. Finally, MAOA showed strong heterogeneous methylation patterns of its DMR in normal somatic adult tissue, but largely variable methylation levels and relatively homogeneous methylation patterns in aborted cloned fetuses. Our data indicate that the aborted cloned fetuses exhibited abnormal methylation imprints, to different extent, in aborted clones, which partially account for the higher abortion and developmental abnormalities during bovine cloning.

  5. Effect of induced transverse chromatic aberration on peripheral vision.

    PubMed

    Winter, Simon; Fathi, Mohammad Taghi; Venkataraman, Abinaya Priya; Rosén, Robert; Seidemann, Anne; Esser, Gregor; Lundström, Linda; Unsbo, Peter

    2015-10-01

    Transverse chromatic aberration (TCA) is one of the largest optical errors affecting the peripheral image quality in the human eye. However, the effect of chromatic aberrations on our peripheral vision is largely unknown. This study investigates the effect of prism-induced horizontal TCA on vision, in the central as well as in the 20° nasal visual field, for four subjects. Additionally, the magnitude of induced TCA (in minutes of arc) was measured subjectively in the fovea with a Vernier alignment method. During all measurements, the monochromatic optical errors of the eye were compensated for by adaptive optics. The average reduction in foveal grating resolution was about 0.032 ± 0.005  logMAR/arcmin of TCA (mean ± std). For peripheral grating detection, the reduction was 0.057 ± 0.012  logMAR/arcmin. This means that the prismatic effect of highly dispersive spectacles may reduce the ability to detect objects in the peripheral visual field.

  6. Effect of sampling on real ocular aberration measurements

    PubMed Central

    Llorente, Lourdes; Marcos, Susana; Dorronsoro, Carlos; Burns, Stephen A.

    2008-01-01

    The minimum number of samples necessary to fully characterize the aberration pattern of the eye is a question under debate in the clinical as well as the scientific community. We performed repeated measurements of ocular aberrations in 12 healthy nonsurgical human eyes and in 3 artificial eyes, using different sampling patterns (hexagonal, circular, and rectangular with 19 to 177 samples, and 3 radial patterns with 49 sample coordinates corresponding to zeros of the Albrecht, Jacobi, and Legendre functions). For each measurement set we computed two different metrics based on the root-mean-square (RMS) of difference maps (RMS_Diff) and the proportional change in the wavefront (W%). These metrics are used to compare wavefront estimates as well as to summarize results across eyes. We used computer simulations to extend our results to “abnormal eyes” (keratoconic, post-LASIK, and post-radial keratotomy eyes). We found that the spatial distribution of the samples can be more important than the number of samples for both our measured as well as our simulated “abnormal” eyes. Experimentally, we did not find large differences across patterns except, as expected, for undersampled patterns. PMID:17767247

  7. Diverticula of Kommerell and Aberrant Subclavian Arteries Complicated by Aneurysms

    SciTech Connect

    Fisher, R. G. Whigham, C. J.; Trinh, C.

    2005-06-15

    This is a retrospective evaluation of the incidence of aberrant subclavian arteries (ASAs) and diverticula of Kommerell, as well as the occurrence and significance of associated aneurysms. Thoracic aortograms obtained during a 12.5-year period were reviewed, seeking the presence of aberrant right and left subclavian arteries (ARSAs/ALSAs), diverticula of Kommerell, and the incidence of associated aortic aneurysms. Several cases were evaluated with computed tomography concomitantly. Results were correlated with a literature review. Twenty-two ASAs were identified. Nineteen were on the right (ARSAs) and three were on the left (ALSAs). A diverticulum of Kommerell (DOK) was also present on the right in seven and on the left in three. Five of these patients had complicating aneurysms. Four of these were associated with ARSAs and their diverticula. Two were atherosclerotic; one was a limited dissection and one of uncertain etiology was ruptured. One additional aneurysm (atherosclerotic) involved an ALSA/DOK. The patient with the ruptured aneurysm died in surgery; three were managed conservatively because of concomitant disease; and one is being followed because of the small size (2.5 cm) of the aneurysm. ARSAs are relatively uncommon and ALSAs are rare. Both ARSA and ALSA are frequently associated with a DOK. Aneurysms rarely involve ASAs (with or without a DOK), but they are associated with a high mortality rate if they are not discovered before rupture. Early diagnosis plus surgical and/or endovascular management can be lifesaving.

  8. Shape Preserving Spline Interpolation

    NASA Technical Reports Server (NTRS)

    Gregory, J. A.

    1985-01-01

    A rational spline solution to the problem of shape preserving interpolation is discussed. The rational spline is represented in terms of first derivative values at the knots and provides an alternative to the spline-under-tension. The idea of making the shape control parameters dependent on the first derivative unknowns is then explored. The monotonic or convex shape of the interpolation data can then be preserved automatically through the solution of the resulting non-linear consistency equations of the spline.

  9. The Distribution of Chromosomal Aberrations in Human Cells Predicted by a Generalized Time-Dependent Model of Radiation-Induced Formation of Aberrations

    NASA Technical Reports Server (NTRS)

    Ponomarev, Artem L.; George, K.; Cucinotta, F. A.

    2011-01-01

    New experimental data show how chromosomal aberrations for low- and high-LET radiation are dependent on DSB repair deficiencies in wild-type, AT and NBS cells. We simulated the development of chromosomal aberrations in these cells lines in a stochastic track-structure-dependent model, in which different cells have different kinetics of DSB repair. We updated a previously formulated model of chromosomal aberrations, which was based on a stochastic Monte Carlo approach, to consider the time-dependence of DSB rejoining. The previous version of the model had an assumption that all DSBs would rejoin, and therefore we called it a time-independent model. The chromosomal-aberrations model takes into account the DNA and track structure for low- and high-LET radiations, and provides an explanation and prediction of the statistics of rare and more complex aberrations. We compared the program-simulated kinetics of DSB rejoining to the experimentally-derived bimodal exponential curves of the DSB kinetics. We scored the formation of translocations, dicentrics, acentric and centric rings, deletions, and inversions. The fraction of DSBs participating in aberrations was studied in relation to the rejoining time. Comparisons of simulated dose dependence for simple aberrations to the experimental dose-dependence for HF19, AT and NBS cells will be made.

  10. The shape of thought.

    PubMed

    Markson, Lori; Diesendruck, Gil; Bloom, Paul

    2008-03-01

    When children learn the name of a novel object, they tend to extend that name to other objects similar in shape - a phenomenon referred to as the shape bias. Does the shape bias stem from learned associations between names and categories of objects, or does it derive from more general properties of children's understanding of language and the world? We argue here for the second alternative, presenting evidence that the shape bias emerges early in development, is not limited to names, and is intimately related to how children make sense of categories.

  11. Method for measuring ocular aberrations induced by thermal lensing in vivo

    NASA Astrophysics Data System (ADS)

    Vincelette, Rebecca; Oliver, Jeff; Noojin, Gary; Schuster, Kurt; Shingledecker, Aurora; Welch, Ashley J.

    2010-02-01

    An adaptive optics imaging system was used to qualitatively observe the types of aberrations induced by an infrared laser in a rhesus eye. Thermal lensing was induced with an infrared laser radiation wavelength of 1150-nm. The adaptive optics system tracked the temporal response of the aberrations at a frequency of 30 Hz for continuous-wave exposures. Results are compared against thermal lensing aberrations induced in an artificial eye.

  12. Effects of the cornea and the crystalline lens on the aberrations of the complete eye

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Wang, Zhaoqi; Wang, Yan; Zuo, Tong

    2005-12-01

    In order to understand the relative contribution of the wave-front aberrations of the cornea and the crystalline lens to the retinal image quality in the human eye, we have measured the wave-front aberrations of the anterior corneal surface, the posterior corneal surface and the complete eye with a corneal topographic system (Orbscan) and a Hartmann-Shack wave-front sensor. The 20 subjects selected to participate in the study are all no eye diseases, covering a range of age from 18 to 25. All the subjects have refractive errors of defocus varying from 0.5 D to 5 D and astigmatism varying from 0.1 D to 1.5D. Using the Orbscan, we obtained the discrete set of corneal elevation data in radial distribution over the pupil plane for the anterior and the posterior corneal surfaces directly, and the data are then transformed into wave-front aberrations of both the corneal surfaces. The wave-front aberrations of the two surfaces are then used to acquire the aberrations in whole cornea. The aberration contribution of the crystalline lens is obtained by subtracting the aberrations in the cornea from that in the complete eye. It is shown that the combination of the aberrations between the crystalline lens and the cornea could be either a compensatory or an additive process. The effect of the combination between the anterior and the posterior corneal surface is also complicated, and the aberration compensation, as well as aberration addition can be observed. It is shown from statistics point of view that the anterior corneal surface contributes more lower-order aberrations (astigmatism) to the complete eye, while the posterior corneal surface and the crystalline lens play a more important role in contributing higher-order aberrations.

  13. A model of field and spherical aberration in soft/hard edge solenoid magnets.

    PubMed

    Biswas, B

    2013-10-01

    A solenoid magnetic field model is presented that describes the on axis field by a parameter of its hard edginess and axial half-width at half-maximum field, which universally define its spherical aberration without solving the ray equation. The model shows an increase in spherical aberration from real soft edge fields to hard edge models, as used in beam tracking. It compares well with existing field models. It simply and accurately finds the spherical aberration in many types of solenoids.

  14. A method of dynamic chromatic aberration correction in low-voltage scanning electron microscopes.

    PubMed

    Khursheed, Anjam

    2005-07-01

    A time-of-flight concept that dynamically corrects for chromatic aberration effects in scanning electron microscopes (SEMs) is presented. The method is predicted to reduce the microscope's chromatic aberration by an order of magnitude. The scheme should significantly improve the spatial resolution of low-voltage scanning electron microscopes (LVSEMs). The dynamic means of correcting for chromatic aberration also allows for the possibility of obtaining high image resolution from electron guns that have relatively large energy spreads.

  15. The definition of optical systems aberrations to secondary school students regarding their knowledge of mathematics

    NASA Astrophysics Data System (ADS)

    Kordek, David

    2017-01-01

    The problematics of optical systems aberrations that is described in my article is beyond mathematical knowledge of secondary school students, especially the problematics of simulations of these aberrations. In my contribution the problematics of optical systems aberrations will be described using higher level-mathematics. Then it will be presented to secondary school students regarding their theoretical knowledge of mathematics. Even though i&tacute;s necessary to include mathematics into clearly physics problem.

  16. Effect of temperature gradients on the wave aberration in athermal optical glasses.

    PubMed

    Reitmayer, F; Schroeder, H

    1975-03-01

    Temperature gradients that are caused by partial heating in optical elements may result in wave aberrations. The athermal glasses developed within the past two years exhibit considerably reduced thermal wave aberrations compared to the classical optical glasses. Evidence is given that the total wave aberration is due not only to the change of optical path DeltaW(Gamma) computed from a, n, and dn/dT, but also that, upon the occurrence of thermal stresses, an additional wave aberration DeltaW(s) must be taken into consideration.

  17. Evaluation of large aberrations using a lateral-shear interferometer having variable shear.

    PubMed

    Rimmer, M P; Wyant, J C

    1975-01-01

    A variable shear lateral shearing interferometer consisting of two holographically produced crossed diffraction gratings is used to test nonrotationally symmetric wavefronts having aberrations greater than 100 wavelengths and slope variations of more than 400 wavelengths/diameter. Comparisons are made with results of Twyman-Green interferometric tests for wavefront aberrations of up to thirty wavelengths. The results indicate that small wavefront aberrations can be measured as accurately with the lateral-shear interferometer as with the Twyman-Green interferometer and that aberrations that cannot be measured at all with a Twyman-Green interferometer can be measured to about 1% accuracy or better.

  18. Aberration fields of off-axis two-mirror astronomical telescopes induced by lateral misalignments.

    PubMed

    Ju, Guohao; Yan, Changxiang; Gu, Zhiyuan; Ma, Hongcai

    2016-10-17

    This paper presents a systematic and in-depth discussion for the aberration fields of off-axis two-mirror astronomical telescopes with an offset pupil that is induced by lateral misalignment. Based on the framework of nodal aberration theory and a system level pupil coordinate transformation, the aberration function for misaligned off-axis telescopes is derived. Some general descriptions for the misalignment-induced aberrations are presented. The specific astigmatic and coma aberration field characteristics in off-axis two-mirror telescopes are then discussed. The precision of the presented aberration expressions is demonstrated. The discrepancies between the ray tracing data and aberration expressions are explicated. Then the inherent relationships between the astigmatism and coma aberration fields are revealed and explicated. Based on this knowledge, some quantitative discussions are further presented for determining the misalignments used to compensate for the effects of primary mirror astigmatic figure errors as well as separating these two effects when coupled. Other effects of lateral misalignments are also presented, especially the field-constant focal shift, which is only sensitive to the lateral misalignments in the symmetry plane of the nominal off-axis system. A quantitative discussion is also presented which explains the reason why trefoil aberration in off-axis telescopes is more sensitive to lateral misalignments. Most of the results presented in this paper can be extended to the other off-axis astronomical telescopes with more freedoms.

  19. Efficient estimation and large-scale evaluation of lateral chromatic aberration for digital image forensics

    NASA Astrophysics Data System (ADS)

    Gloe, Thomas; Borowka, Karsten; Winkler, Antje

    2010-01-01

    The analysis of lateral chromatic aberration forms another ingredient for a well equipped toolbox of an image forensic investigator. Previous work proposed its application to forgery detection1 and image source identification.2 This paper takes a closer look on the current state-of-the-art method to analyse lateral chromatic aberration and presents a new approach to estimate lateral chromatic aberration in a runtime-efficient way. Employing a set of 11 different camera models including 43 devices, the characteristic of lateral chromatic aberration is investigated in a large-scale. The reported results point to general difficulties that have to be considered in real world investigations.

  20. Measurement of chromatic aberration in STEM and SCEM by coherent convergent beam electron diffraction.

    PubMed

    Zheng, C L; Etheridge, J

    2013-02-01

    A simple method is described for the accurate and precise measurement of chromatic aberration under electron-optical conditions pertinent to scanning transmission electron microscopy (STEM) and scanning confocal electron microscopy (SCEM). The method requires only the measurement of distances in a coherent CBED pattern and knowledge of the electron wavelength and the lattice spacing of a calibration specimen. The chromatic aberration of a spherical-aberration corrected 300 kV thermal field emission TEM is measured in STEM and SCEM operating modes and under different condenser lens settings. The effect of the measured chromatic aberrations on the 3 dimensional intensity distribution of the electron probe is also considered.

  1. Influence of ocular longitudinal chromatic aberration on the selection of aspheric intraocular lenses.

    PubMed

    Hong, Xin; Choi, Myoung

    2010-12-06

    Polychromatic defocus could affect the optimal residual spherical aberration that could yield the best image quality for patients with intraocular lenses (IOLs). Modulation transfer functions (MTFs) were generated using a model that included polychromatic defocus. The maximum MTF volume occurred at + 0.05 μm of overall ocular spherical aberration. For 3 case studies, the optimal overall ocular spherical aberration was ~0.05 μm more positive with the contribution of polychromatic defocus than without it. Overall, the model indicated that image quality was usually best when IOLs allowed overall ocular spherical aberration that was slightly positive, rather than strongly positive, zero, or negative.

  2. Primary wavefront aberrations calculation from a defocused image or a Hartmanngram.

    PubMed

    Malacara-Doblado, Daniel; Malacara-Hernández, Zacarias; Gómez-Vieyra, Armando

    2010-04-20

    A wavefront aberration can be retrieved from a defocused image or a Hartmanngram by several different methods using diffraction theory and Fourier transforms. In this manuscript, we describe an alternate method for wavefront aberration determination from a defocused image or a Hartmanngram using a geometric l approximation. The main assumption is that the image is defocused, with the observation plane outside the caustic limits. The result will be applied to the retrieval of a wavefront with primary aberrations from a Hartmanngram or defocused image without the need for any transversal aberration integration.

  3. Magnitude of speed of sound aberration corrections for ultrasound image guided radiotherapy for prostate and other anatomical sites

    SciTech Connect

    Fontanarosa, Davide; Meer, Skadi van der; Bloemen-van Gurp, Esther; Stroian, Gabriela; Verhaegen, Frank

    2012-08-15

    Purpose: The purpose of this work is to assess the magnitude of speed of sound (SOS) aberrations in three-dimensional ultrasound (US) imaging systems in image guided radiotherapy. The discrepancy between the fixed SOS value of 1540 m/s assumed by US systems in human soft tissues and its actual nonhomogeneous distribution in patients produces small but systematic errors of up to a few millimeters in the positions of scanned structures. Methods: A correction, provided by a previously published density-based algorithm, was applied to a set of five prostate, five liver, and five breast cancer patients. The shifts of the centroids of target structures and the change in shape were evaluated. Results: After the correction the prostate cases showed shifts up to 3.6 mm toward the US probe, which may explain largely the reported positioning discrepancies in the literature on US systems versus other imaging modalities. Liver cases showed the largest changes in volume of the organ, up to almost 9%, and shifts of the centroids up to more than 6 mm either away or toward the US probe. Breast images showed systematic small shifts of the centroids toward the US probe with a maximum magnitude of 1.3 mm. Conclusions: The applied correction in prostate and liver cancer patients shows positioning errors of several mm due to SOS aberration; the errors are smaller in breast cancer cases, but possibly becoming more important when breast tissue thickness increases.

  4. Nanostructure and crystallography of aberrant columnar vaterite in Corbicula fluminea (Mollusca).

    PubMed

    Frenzel, Max; Harrison, Richard J; Harper, Elizabeth M

    2012-04-01

    Both the crystallographic and nanostructural organisation of aberrant columnar vaterite occurring in Corbicula fluminea were characterised in detail for the first time using electron microscopic and X-ray powder diffraction techniques. At the millimetre scale, only a confinement of the otherwise randomly oriented c-axis to the growth surface is observed. Domains of 100 or more individual vaterite columns with common c-axis orientation exist within this disordered material. Each column behaves as a single crystal on the scale of EBSD measurements, but is internally composed of smaller irregularly shaped and slightly misaligned crystalline units (0.3-1.3μm in dimension). These are in turn partitioned by porous boundaries into rounded nanodomains, up to 600nm in size. The geometry of the nanodomains and their respective boundaries might suggest formation by the accretion of vesicles. In addition to crystallographic textures, this observation indicates formation under significant biological control with wider implications for possible causes of the condition.

  5. Epigenetic repression of ribosomal RNA transcription by ROCK-dependent aberrant cytoskeletal organization

    PubMed Central

    Wu, Tse-Hsiang; Kuo, Yuan-Yeh; Lee, Hsiao-Hui; Kuo, Jean-Cheng; Ou, Meng-Hsin; Chang, Zee-Fen

    2016-01-01

    It is known that ribosomal RNA (rRNA) synthesis is regulated by cellular energy and proliferation status. In this study, we investigated rRNA gene transcription in response to cytoskeletal stress. Our data revealed that the cell shape constrained by isotropic but not elongated micropatterns in HeLa cells led to a significant reduction in rRNA transcription dependent on ROCK. Expression of a dominant-active form of ROCK also repressed rRNA transcription. Isotropic constraint and ROCK over-activation led to different types of aberrant F-actin organization, but their suppression effects on rRNA transcription were similarly reversed by inhibition of histone deacetylase (HDAC) or overexpression of a dominant negative form of Nesprin, which shields the signal transmitted from actin filament to the nuclear interior. We further showed that the binding of HDAC1 to the active fraction of rDNA genes is increased by ROCK over-activation, thus reducing H3K9/14 acetylation and suppressing transcription. Our results demonstrate an epigenetic control of active rDNA genes that represses rRNA transcription in response to the cytoskeletal stress. PMID:27350000

  6. Chemopreventive Efficacy of Andrographis paniculata on Azoxymethane-Induced Aberrant Colon Crypt Foci In Vivo

    PubMed Central

    Al-Henhena, Nawal; Ying, Rozaida Poh Yuen; Ismail, Salmah; Najm, Wala; Khalifa, Shaden A. M.; El-Seedi, Hesham; Abdulla, Mahmood Ameen

    2014-01-01

    Andrographis paniculata is a grass-shaped medicinal herb, traditionally used in Southeast Asia. The aim of this study was to evaluate the chemoprotective effects of A. paniculata on colorectal cancer. A. paniculata ethanol extract was tested on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in vivo and in vitro. A. paniculata treated groups showed a significant reduction in the number of ACF of the treated rats. Microscopically, ACF showed remarkably elongated and stratified cells, and depletion of the submucosal glands of AOM group compared to the treated groups. Histologically, staining showed slightly elevated masses above the surrounding mucosa with oval or slit-like orifices. Immunohistochemically, expression of proliferating cell nuclear antigen (PCNA) and β-catenin protein were down-regulated in the A. paniculata treated groups compared to the AOM group. When colon tissue was homogenized, malondialdehyde (MDA) and nitric oxide (NO) levels were significantly decreased, whereas superoxide dismutase (SOD) activity was increased in the treated groups compared to the AOM group. A. paniculata ethanol extract showed antioxidant and free radical scavenging activity, as elucidated by the measure of oxidative stress markers. Further, the active fractions were assessed against cell lines of CCD841 and HT29 colon cancer cells. PMID:25390042

  7. Chemopreventive efficacy of Andrographis paniculata on azoxymethane-induced aberrant colon crypt foci in vivo.

    PubMed

    Al-Henhena, Nawal; Ying, Rozaida Poh Yuen; Ismail, Salmah; Najm, Walaa; Najm, Wala; Khalifa, Shaden A M; El-Seedi, Hesham; Ameen Abdulla, Mahmood; Abdulla, Mahmood Ameen

    2014-01-01

    Andrographis paniculata is a grass-shaped medicinal herb, traditionally used in Southeast Asia. The aim of this study was to evaluate the chemoprotective effects of A. paniculata on colorectal cancer. A. paniculata ethanol extract was tested on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in vivo and in vitro. A. paniculata treated groups showed a significant reduction in the number of ACF of the treated rats. Microscopically, ACF showed remarkably elongated and stratified cells, and depletion of the submucosal glands of AOM group compared to the treated groups. Histologically, staining showed slightly elevated masses above the surrounding mucosa with oval or slit-like orifices. Immunohistochemically, expression of proliferating cell nuclear antigen (PCNA) and β-catenin protein were down-regulated in the A. paniculata treated groups compared to the AOM group. When colon tissue was homogenized, malondialdehyde (MDA) and nitric oxide (NO) levels were significantly decreased, whereas superoxide dismutase (SOD) activity was increased in the treated groups compared to the AOM group. A. paniculata ethanol extract showed antioxidant and free radical scavenging activity, as elucidated by the measure of oxidative stress markers. Further, the active fractions were assessed against cell lines of CCD841 and HT29 colon cancer cells.

  8. Odd Shape Out

    ERIC Educational Resources Information Center

    Cady, Jo Ann; Wells, Pamela

    2016-01-01

    The Odd Shape Out task was an open-ended problem that engaged students in comparing shapes based on their properties. Four teachers submitted the work of 116 students from across the country. This article compares various student's responses to the task. The problem allowed for differentiation, as shown by the many different ways that students…

  9. Crystal Shape Bingo.

    ERIC Educational Resources Information Center

    Rule, Audrey C.

    This document describes a game that provides students with practice in recognizing three dimensional crystal shapes and planar geometric shapes of crystal faces. It contains information on the objective of the game, game preparation, and rules for playing. Play cards are included (four to a page). (ASK)

  10. Pulse shaping system

    DOEpatents

    Skeldon, Mark D.; Letzring, Samuel A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

  11. Pulse shaping system

    DOEpatents

    Skeldon, M.D.; Letzring, S.A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

  12. Optimization of lens shape for autostereoscopic display

    NASA Astrophysics Data System (ADS)

    Su, Ping; An, Shu; Ma, Jianshe

    2016-10-01

    The three-dimensional(3D) displays based on binocular parallax have drawn increasingly interests. The light splitting element, which presents separate images to the viewer's left and right eyes, plays an important part in the auto-stereoscopic display. Lenticular lenses are widely used as the light splitting elements. However, the crosstalk resulted from the unsatisfied splitting may reduce the 3D experience. It was determined that the most suitable cross sectional shape for lenticular lenses is elliptical. Firstly, the formula of the surface is derived based on the ellipse expression and the requirement of the 3D display system, that is y2+0.5651x2 - 303.4768=0. Secondly, one axial source and 4 off-axial sources placed at the heights of 2.5mm, 5mm, 7.5mm and 8mm are used to analyze the beam splitting quality of the cylindrical and elliptical lens element, respectively. The spot of elliptical lens is smaller which means a better beam splitting quality. Thirdly, Monte Carlo Non-Sequential Ray tracing algorithm is used to simulate the luminance distribution on the viewing plane, the narrower width of vertical stripes means that the aberration is suppressed. Finally, the shape of elliptical can reduce the processing difficulty with the 10μm minimum step width. In a word, the optimization of the surface has a significant effect on the improvement of stereoscopic depth and the reduction of ghost images.

  13. Correction of the phase distortion for high power laser by freeform shape mirror

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Tang, Xiaojun; Ren, Jianfeng; Huang, Qitai; Wang, Wentao

    2016-11-01

    The wavefront can keep stable while the laser system is adjusted well. Based on this characteristic, in order to improve the beam quality, we suggest to make mirror of free-form surface to compensate for the laser wavefront aberration. First, the theory of aberration compensated with free-form shape mirror is introduced, then through computer simulation, the mirror's capability of is discussed, lastly, the mirror is used by laser system which the average output power is 12.5KW. By the using of free-form shape mirror, laser's wavefront, beam quality of farfield and intensity of nearfield are improved obviously: the intensity of nearfield F is improved from 0.15 to 0.39; the wavefront's PV is improved from 6.3μm to 1.7μm the wavefront's rms is improved from 2.0μm to 0.4μm the beam quality of farfield β is improved from 5.25 to 1.8. Compared with deformable mirror of adaptive optics, the free-form shape mirror has its own advantage: low cost; with no increase to laser system complication; the free-from shape mirror can be used to compensated for high order wavefront aberration effectively.

  14. Ocular wavefront aberrations in the common marmoset Callithrix jacchus: effects of age and refractive error.

    PubMed

    Coletta, Nancy J; Marcos, Susana; Troilo, David

    2010-11-23

    The common marmoset, Callithrix jacchus, is a primate model for emmetropization studies. The refractive development of the marmoset eye depends on visual experience, so knowledge of the optical quality of the eye is valuable. We report on the wavefront aberrations of the marmoset eye, measured with a clinical Hartmann-Shack aberrometer (COAS, AMO Wavefront Sciences). Aberrations were measured on both eyes of 23 marmosets whose ages ranged from 18 to 452 days. Twenty-one of the subjects were members of studies of emmetropization and accommodation, and two were untreated normal subjects. Eleven of the 21 experimental subjects had worn monocular diffusers and 10 had worn binocular spectacle lenses of equal power. Monocular deprivation or lens rearing began at about 45 days of age and ended at about 108 days of age. All refractions and aberration measures were performed while the eyes were cyclopleged; most aberration measures were made while subjects were awake, but some control measurements were performed under anesthesia. Wavefront error was expressed as a seventh-order Zernike polynomial expansion, using the Optical Society of America's naming convention. Aberrations in young marmosets decreased up to about 100 days of age, after which the higher-order RMS aberration leveled off to about 0.10 μm over a 3 mm diameter pupil. Higher-order aberrations were 1.8 times greater when the subjects were under general anesthesia than when they were awake. Young marmoset eyes were characterized by negative spherical aberration. Form-deprived eyes of the monocular deprivation animals had greater wavefront aberrations than their fellow untreated eyes, particularly for asymmetric aberrations in the odd-numbered Zernike orders. Both lens-treated and form-deprived eyes showed similar significant increases in Z3(-3) trefoil aberration, suggesting the increase in trefoil may be related to factors that do not involve visual feedback.

  15. Letter: A method for the chromatic aberration correction of a laser time of-flight mass analyzer.

    PubMed

    Sysoeva, Elizaveta A; Sysoev, Alexander A

    2016-01-01

    The new ion-optical system of the laser time-of-flight (TOF) mass spectrometer on the basis of two tandem wedge-shape reflectors has been offered and implemented. A new method of correcting chromatic aberration by the ion energy was proposed that used a wire electrode unit with adjustable potentials. This unit allows one to adjust the local TOF of the ions in a narrow energy range ± (1-2)% within the total ion packet with an energy spread of ± 20%. The method reduces the duration of the ion packets by up to 1.5ns, which enables us to obtain the restriction of resolution at a level not worse than R ~ 10500 for a TOF ~35 µs. The aim of the project is to increase the separation of isobaric ions to improve the limit of detection of the laser TOF-MS for the analysis of high-purity samples.

  16. Aberration-free, all-reflective laser pulse stretcher

    DOEpatents

    Perry, Michael D.; Banks, Paul S.; Stuart, Brent C.; Fochs, Scott N.

    1999-09-28

    An all-reflective pulse stretcher for laser systems employing chirped-pulse amplification enables on-axis use of the focusing mirror which results in ease of use, significantly decreased sensitivity to alignment and near aberration-free performance. By using a new type of diffraction grating which contains a mirror incorporated into the grating, the stretcher contains only three elements: 1) the grating, 2) a spherical or parabolic focusing mirror, and 3) a flat mirror. Addition of a fourth component, a retro-reflector, enables multiple passes of the same stretcher resulting in stretching ratios beyond the current state of the art in a simple and compact design. The pulse stretcher has been used to stretch pulses from 20 fsec to over 600 psec (a stretching ratio in excess of 30,000).

  17. Catadioptric lens with aberrations balanced by aspherizing one surface

    NASA Astrophysics Data System (ADS)

    Bystricky, K. M.; Yoder, P. R., Jr.

    1985-04-01

    In this paper a description is provided of an optical system with one surface aspherized to give a specific level of performance and to equalize the intensity profiles of star images over the field. The system was a 25.4-cm EFL, 5.8 deg field, f/1.53 catadioptric Cassegrain. It was designed to determine the attitude of a space platform by detecting and mapping the geometric pattern of stars observed to ninth visual magnitude. Aberrations were controlled over a 0.5-1.1-micron spectral region. A comparison is conducted of the polychromatic performance of the design to one conventionally optimized. How the spherical substrate base radius was chosen to minimize glass removal is also described.

  18. Geometrical Aberration Suppression for Large Aperture Sub-THz Lenses

    NASA Astrophysics Data System (ADS)

    Rachon, M.; Liebert, K.; Siemion, A.; Bomba, J.; Sobczyk, A.; Knap, W.; Coquillat, D.; Suszek, J.; Sypek, M.

    2017-03-01

    Advanced THz setups require high performance optical elements with large numerical apertures and small focal lengths. This is due to the high absorption of humid air and relatively low efficiency of commercially available detectors. Here, we propose a new type of double-sided sub-THz diffractive optical element with suppressed geometrical aberration for narrowband applications (0.3 THz). One side of the element is designed as thin structure in non-paraxial approach which is the exact method, but only for ideally flat elements. The second side will compensate phase distribution differences between ideal thin structure and real volume one. The computer-aided optimization algorithm is performed to design an additional phase distribution of correcting layer assuming volume designing of the first side of the element. The experimental evaluation of the proposed diffractive component created by 3D printing technique shows almost two times larger performance in comparison with uncorrected basic diffractive lens.

  19. Geometrical Aberration Suppression for Large Aperture Sub-THz Lenses

    NASA Astrophysics Data System (ADS)

    Rachon, M.; Liebert, K.; Siemion, A.; Bomba, J.; Sobczyk, A.; Knap, W.; Coquillat, D.; Suszek, J.; Sypek, M.

    2016-11-01

    Advanced THz setups require high performance optical elements with large numerical apertures and small focal lengths. This is due to the high absorption of humid air and relatively low efficiency of commercially available detectors. Here, we propose a new type of double-sided sub-THz diffractive optical element with suppressed geometrical aberration for narrowband applications (0.3 THz). One side of the element is designed as thin structure in non-paraxial approach which is the exact method, but only for ideally flat elements. The second side will compensate phase distribution differences between ideal thin structure and real volume one. The computer-aided optimization algorithm is performed to design an additional phase distribution of correcting layer assuming volume designing of the first side of the element. The experimental evaluation of the proposed diffractive component created by 3D printing technique shows almost two times larger performance in comparison with uncorrected basic diffractive lens.

  20. The Oncoprotein BRD4-NUT Generates Aberrant Histone Modification Patterns.

    PubMed

    Zee, Barry M; Dibona, Amy B; Alekseyenko, Artyom A; French, Christopher A; Kuroda, Mitzi I

    2016-01-01

    Defects in chromatin proteins frequently manifest in diseases. A striking case of a chromatin-centric disease is NUT-midline carcinoma (NMC), which is characterized by expression of NUT as a fusion partner most frequently with BRD4. ChIP-sequencing studies from NMC patients revealed that BRD4-NUT (B4N) covers large genomic regions and elevates transcription within these domains. To investigate how B4N modulates chromatin, we performed affinity purification of B4N when ectopically expressed in 293-TREx cells and quantified the associated histone posttranslational modifications (PTM) using proteomics. We observed significant enrichment of acetylation particularly on H3 K18 and of combinatorial patterns such as H3 K27 acetylation paired with K36 methylation. We postulate that B4N complexes override the preexisting histone code with new PTM patterns that reflect aberrant transcription and that epigenetically modulate the nucleosome environment toward the NMC state.

  1. The Oncoprotein BRD4-NUT Generates Aberrant Histone Modification Patterns

    PubMed Central

    Zee, Barry M.; Dibona, Amy B.; Alekseyenko, Artyom A.; French, Christopher A.; Kuroda, Mitzi I.

    2016-01-01

    Defects in chromatin proteins frequently manifest in diseases. A striking case of a chromatin-centric disease is NUT-midline carcinoma (NMC), which is characterized by expression of NUT as a fusion partner most frequently with BRD4. ChIP-sequencing studies from NMC patients revealed that BRD4-NUT (B4N) covers large genomic regions and elevates transcription within these domains. To investigate how B4N modulates chromatin, we performed affinity purification of B4N when ectopically expressed in 293-TREx cells and quantified the associated histone posttranslational modifications (PTM) using proteomics. We observed significant enrichment of acetylation particularly on H3 K18 and of combinatorial patterns such as H3 K27 acetylation paired with K36 methylation. We postulate that B4N complexes override the preexisting histone code with new PTM patterns that reflect aberrant transcription and that epigenetically modulate the nucleosome environment toward the NMC state. PMID:27698495

  2. Chromosome Aberrations and Fertility Disorders in Domestic Animals.

    PubMed

    Raudsepp, Terje; Chowdhary, Bhanu P

    2016-01-01

    The association between chromosomal abnormalities and reduced fertility in domestic animals is well recorded and has been studied for decades. Chromosome aberrations directly affect meiosis, gametogenesis, and the viability of zygotes and embryos. In some instances, balanced structural rearrangements can be transmitted, causing fertility problems in subsequent generations. Here, we aim to give a comprehensive overview of the current status and future prospects of clinical cytogenetics of animal reproduction by focusing on the advances in molecular cytogenetics during the genomics era. We describe how advancing knowledge about animal genomes has improved our understanding of connections between gross structural or molecular chromosome variations and reproductive disorders. Further, we expand on a key area of reproduction genetics: cytogenetics of animal gametes and embryos. Finally, we describe how traditional cytogenetics is interfacing with advanced genomics approaches, such as array technologies and next-generation sequencing, and speculate about the future prospects.

  3. Longitudinal chromatic aberration of the human infant eye.

    PubMed

    Wang, Jingyun; Candy, T Rowan; Teel, Danielle F W; Jacobs, Robert J

    2008-09-01

    Although the longitudinal chromatic aberration (LCA) of the adult eye has been studied, there are no data collected from the human infant eye. A chromatic retinoscope was used to measure cyclopleged infant and adult refractions with four pseudomonochromatic sources (centered at 472, 538, 589, and 652 nm) and with polychromatic light. The LCA of the infant eyes between 472 and 652 nm was a factor of 1.7 greater than the LCA found in the adult group: infant mean=1.62 D, SD+/- 0.14 D; adult mean=0.96 D, SD+/- 0.17 D. The elevated level of LCA in infant eyes is consistent with the greater optical power of the immature eye and indicates similar chromatic dispersion in infant and adult eyes. The implications for visual performance, defocus detection, and measurement of refraction are discussed.

  4. Mutational consequences of aberrant ion channels in neurological disorders.

    PubMed

    Kumar, Dhiraj; Ambasta, Rashmi K; Kumar, Pravir

    2014-11-01

    Neurological channelopathies are attributed to aberrant ion channels affecting CNS, PNS, cardiac, and skeletal muscles. To maintain the homeostasis of excitable tissues, functional ion channels are necessary to rely electrical signals, whereas any malfunctioning serves as an intrinsic factor to develop neurological channelopathies. Molecular basis of these disease is studied based on genetic and biophysical approaches, e.g., loci positional cloning, whereas pathogenesis and bio-behavioral analysis revealed the dependency on genetic mutations and inter-current triggering factors. Although electrophysiological studies revealed the possible mechanisms of diseases, analytical study of ion channels remained unsettled and therefore underlying mechanism in channelopathies is necessary for better clinical application. Herein, we demonstrated (i) structural and functional role of various ion channels (Na(+), K(+), Ca(2+),Cl(-)), (ii) pathophysiology involved in the onset of their associated channelopathies, and (iii) comparative sequence and phylogenetic analysis of diversified sodium, potassium, calcium, and chloride ion channel subtypes.

  5. Fast and robust estimation of ophthalmic wavefront aberrations

    NASA Astrophysics Data System (ADS)

    Dillon, Keith

    2016-12-01

    Rapidly rising levels of myopia, particularly in the developing world, have led to an increased need for inexpensive and automated approaches to optometry. A simple and robust technique is provided for estimating major ophthalmic aberrations using a gradient-based wavefront sensor. The approach is based on the use of numerical calculations to produce diverse combinations of phase components, followed by Fourier transforms to calculate the coefficients. The approach does not utilize phase unwrapping nor iterative solution of inverse problems. This makes the method very fast and tolerant to image artifacts, which do not need to be detected and masked or interpolated as is needed in other techniques. These features make it a promising algorithm on which to base low-cost devices for applications that may have limited access to expert maintenance and operation.

  6. Aberrant meiotic behavior in Agave tequilana Weber var. azul

    PubMed Central

    Ruvalcaba-Ruiz, Domingo; Rodríguez-Garay, Benjamin

    2002-01-01

    Background Agave tequilana Weber var. azul, is the only one variety permitted by federal law in México to be used for tequila production which is the most popular contemporary alcoholic beverage made from agave and recognized worldwide. Despite the economic, genetic, and ornamental value of the plant, it has not been subjected to detailed cytogenetic research, which could lead to a better understanding of its reproduction for future genetic improvement. The objective of this work was to study the meiotic behavior in pollen mother cells and its implications on the pollen viability in Agave tequilana Weber var. azul. Results The analysis of Pollen Mother Cells in anaphase I (A-I) showed 82.56% of cells with a normal anaphase and, 17.44% with an irregular anaphase. In which 5.28% corresponded to cells with side arm bridges (SAB); 3.68% cells with one bridge and one fragment; 2.58% of irregular anaphase showed cells with one or two lagging chromosomes and 2.95% showed one acentric fragment; cells with two bridges and cells with two bridges and one acentric fragment were observed in frequencies of 1.60% and 1.35% respectively. In anaphase II some cells showed bridges and fragments too. Aberrant A-I cells had many shrunken or empty pollen grains (42.00%) and 58.00 % viable pollen. Conclusion The observed meiotic irregularities suggest that structural chromosome aberrations have occurred, such as heterozygous inversions, sister chromatid exchanges, deletions and duplications which in turn are reflected in a low pollen viability. PMID:12396234

  7. Genomic Aberrations Frequently Alter Chromatin Regulatory Genes in Chordoma

    PubMed Central

    Wang, Lu; Zehir, Ahmet; Nafa, Khedoudja; Zhou, Nengyi; Berger, Michael F.; Casanova, Jacklyn; Sadowska, Justyna; Lu, Chao; Allis, C. David; Gounder, Mrinal; Chandhanayingyong, Chandhanarat; Ladanyi, Marc; Boland, Patrick J; Hameed, Meera

    2016-01-01

    Chordoma is a rare primary bone neoplasm that is resistant to standard chemotherapies. Despite aggressive surgical management, local recurrence and metastasis is not uncommon. To identify the specific genetic aberrations that play key roles in chordoma pathogenesis, we utilized a genome-wide high-resolution SNP-array and next generation sequencing (NGS)-based molecular profiling platform to study 24 patient samples with typical histopathologic features of chordoma. Matching normal tissues were available for 16 samples. SNP-array analysis revealed nonrandom copy number losses across the genome, frequently involving 3, 9p, 1p, 14, 10, and 13. In contrast, copy number gain is uncommon in chordomas. Two minimum deleted regions were observed on 3p within a ~8 Mb segment at 3p21.1–p21.31, which overlaps SETD2, BAP1 and PBRM1. The minimum deleted region on 9p was mapped to CDKN2A locus at 9p21.3, and homozygous deletion of CDKN2A was detected in 5/22 chordomas (~23%). NGS-based molecular profiling demonstrated an extremely low level of mutation rate in chordomas, with an average of 0.5 mutations per sample for the 16 cases with matched normal. When the mutated genes were grouped based on molecular functions, many of the mutation events (~40%) were found in chromatin regulatory genes. The combined copy number and mutation profiling revealed that SETD2 is the single gene affected most frequently in chordomas, either by deletion or by mutations. Our study demonstrated that chordoma belongs to the C-class (copy number changes) tumors whose oncogenic signature is non-random multiple copy number losses across the genome and genomic aberrations frequently alter chromatin regulatory genes. PMID:27072194

  8. Low incidence of chromosome aberrations in spermatozoa of fertile boars.

    PubMed

    Orsztynowicz, Maciej; Pawlak, Piotr; Oleś, Dominika; Kubickova, Svatava; Lechniak, Dorota

    2011-11-01

    Chromosomal imbalance in gametes and embryos is one of the factors contributing to early embryonic mortality. Although the rate of chromosomally abnormal sperm cells is low and usually does not exceed 1%, there is no clear indication of fertilizing potential of such gametes. The aim of the experiment was to investigate the type and incidence of numerical chromosomal aberrations in spermatozoa produced by fertile boars used in artificial insemination (AI). We used the protocol of fluorescent in situ hybridization (FISH) on sperm interphase nuclei with molecular probes for porcine chromosome pairs 1 and 10. Altogether 12 348 sperm cells were examined. Disomy was observed in spermatozoa of all seven AI boars whereas only one diploid cell was identified in all screened sperm cells. The average rate of chromosomally unbalanced sperm was 0.105% (13/12 348) with an inter-individual variation from 0.048% to 0.194%. Among abnormal sperm cells, both disomy (0.097%) and diploidy (0.008%) were detected. Nullisomy was not included into calculations. The estimated aneuploidy rate calculated by doubling the number of disomic cells was 0.194%. Chromosome pair 10 was significantly more often involved in non-disjunction (75%, 9/12 aneuploid sperm cells) than chromosome pair 1 (25%, 3/12). We have shown for the pig that the rate of disomic cells falls into a range presented by other authors, whereas that of diploid spermatozoa appeared to be lower in the present study. In conclusion, numerical chromosome aberrations were present in spermatozoa of all AI boars analyzed in this study. Therefore, it can be assumed that the presence of unbalanced spermatozoa at the level observed in fertile males does not significantly affect their reproductive potential.

  9. Chromosome aberration and lipid peroxidation in chromium-exposed workers.

    PubMed

    Maeng, S H; Chung, H W; Kim, K J; Lee, B M; Shin, Y C; Kim, S J; Yu, I J

    2004-01-01

    Chromosome aberration frequency and lipid peroxidation levels were analyzed to investigate their efficacy as biological markers for monitoring the genotoxicity and oxidative damage in Korean chromium (Cr)-exposed workers. Fifty-one Cr-exposed workers and 31 age-matched controls in ten chrome-plating plants were sampled. The Cr level was measured in the workers' blood and urine, and in the ambient air at the workplaces. The conventional Giemsa staining method and fluorescence in situ hybridization (FISH) technique were used for chromosome aberration analysis. Spectrum green whole chromosome paint specific for chromosome 4 was used in the FISH procedure. As for lipid peroxidation, malondialdehyde (MDA) was measured in the blood plasma as thiobarbituric acid-reactive substances (TBARS). The blood Cr concentration was statistically correlated with both the frequency of chromatid exchange and the total frequency of chromosome/chromatid breaks and exchanges, as detected by the Giemsa staining. Meanwhile, the frequency of translocation, as detected by the FISH technique, was significantly higher in the Cr-exposed workers than in the controls and it correlated with the blood Cr concentration. Although the concentration of MDA, the metabolite of lipid peroxidation, in the exposed workers was higher than that of the controls, no statistically significant correlation between the MDA level and the blood or urine Cr levels was observed. Accordingly, the genotoxicity and oxidative damage (plasma lipid peroxidation) in the Korean Cr-exposed workers were consequential at quite low exposure levels, plus chromosome rearrangement, especially translocation, was clearly evident as a biological response marker for Cr exposure based on a significant positive correlation between the translocations detected by FISH and the Cr in the blood.

  10. Regional Specificity of Aberrant Thalamocortical Connectivity in Autism

    PubMed Central

    Nair, Aarti; Carper, Ruth A.; Abbott, Angela E.; Chen, Colleen P.; Solders, Seraphina; Nakutin, Sarah; Datko, Michael C.; Fishman, Inna; Müller, Ralph-Axel

    2016-01-01

    Preliminary evidence suggests aberrant (mostly reduced) thalamocortical (TC) connectivity in autism spectrum disorder (ASD), but despite the crucial role of thalamus in sensorimotor functions and its extensive connectivity with cerebral cortex, relevant evidence remains limited. We performed a comprehensive investigation of region-specific TC connectivity in ASD. Resting-state functional MRI and diffusion tensor imaging (DTI) data were acquired for 60 children and adolescents with ASD (ages 7–17 years) and 45 age, sex, and IQ-matched typically developing (TD) participants. We examined intrinsic functional connectivity (iFC) and anatomical connectivity (probabilistic tractography) with thalamus, using 68 unilateral cerebral cortical regions of interest (ROIs). For frontal and parietal lobes, iFC was atypically reduced in the ASD group for supramodal association cortices, but was increased for cingulate gyri and motor cortex. Temporal iFC was characterized by overconnectivity for auditory cortices, but underconnectivity for amygdalae. Occipital iFC was broadly reduced in the ASD group. DTI indices (such as increased radial diffusion) for regions with group differences in iFC further indicated compromised anatomical connectivity, especially for frontal ROIs, in the ASD group. Our findings highlight the regional specificity of aberrant TC connectivity in ASD. Their overall pattern can be largely accounted for by functional overconnectivity with limbic and sensorimotor regions, but underconnectivity with supramodal association cortices. This could be related to comparatively early maturation of limbic and sensorimotor regions in the context of early overgrowth in ASD, at the expense of TC connectivity with later maturing cortical regions. PMID:26493162

  11. Longitudinal Trajectories of Aberrant Behavior in Fragile X Syndrome

    PubMed Central

    Hustyi, Kristin M.; Hall, Scott S.; Jo, Booil; Lightbody, Amy A.; Reiss, Allan L.

    2016-01-01

    The Aberrant Behavior Checklist—Community (ABC-C; Aman, Burrow, & Wolford, 1995) has been increasingly adopted as a primary tool for measuring behavioral change in clinical trials for individuals with fragile X syndrome (FXS). To our knowledge, however, no study has documented the longitudinal trajectory of aberrant behaviors in individuals with FXS using the ABC-C. As part of a larger longitudinal study, we examined scores obtained on the ABC-C subscales for 124 children and adolescents (64 males, 60 females) with FXS who had two or more assessments (average interval between assessments was approximately 4 years). Concomitant changes in age-equivalent scores on the Vineland Adaptive Behavior Scales (VABS) were also examined. As expected for an X-linked genetic disorder, males with FXS obtained significantly higher scores on all subscales of the ABC-C and significantly lower age-equivalent scores on the VABS than females with FXS. In both males and females with FXS, scores on the Irritability/Agitation and Hyperactivity/Noncompliance subscales of the ABC-C decreased significantly with age, with little to no change occurring over time on the Lethargy/Social Withdrawal, Stereotypic Behavior, and Inappropriate Speech subscales. The decrease in scores on the Hyperactivity/Noncompliance domain was significantly greater for males than for females. In both males and females, age-equivalent scores on the VABS increased significantly over this developmental period. These results establish a basis upon which to evaluate long-term outcomes from intervention-based research. However, longitudinal direct observational studies are needed to establish whether the severity of problem behavior actually decreases over time in this population. PMID:25129200

  12. 50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors.

    PubMed

    Matsuyama, Satoshi; Yasuda, Shuhei; Yamada, Jumpei; Okada, Hiromi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-04-13

    X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick-Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles.

  13. The Shapes of Physics

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2013-12-01

    I have used many ploys to start a course in introductory physics, but one of the more interesting ones was to spend 20 minutes describing some of the curves and shapes that we would encounter in our year together. The students saw parabolas, catenaries, hyperbolas, cycloids, circles, ellipses, and helices, and were shown examples, either live or on slides, of these shapes. The world of physics is three-dimensional, and students need to see what curves and trajectories span it. Once they see these shapes in nature, they look at the world around them in fresh ways.

  14. Shaped Crystal Growth

    NASA Astrophysics Data System (ADS)

    Tatartchenko, Vitali A.

    Crystals of specified shape and size (shaped crystals) with controlled crystal growth (SCG) defect and impurity structure have to be grown for the successful development of modern engineering. Since the 1950s many hundreds of papers and patents concerned with shaped growth have been published. In this chapter, we do not try to enumerate the successful applications of shaped growth to different materials but rather to carry out a fundamental physical and mathematical analysis of shaping as well as the peculiarities of shaped crystal structures. Four main techniques, based on which the lateral surface can be shaped without contact with the container walls, are analyzed: the Czochralski technique (CZT), the Verneuil technique (VT), the floating zone technique (FZT), and technique of pulling from shaper (TPS). Modifications of these techniques are analyzed as well. In all these techniques the shape of the melt meniscus is controlled by surface tension forces, i.e., capillary forces, and here they are classified as capillary shaping techniques (CST). We look for conditions under which the crystal growth process in each CST is dynamically stable. Only in this case are all perturbations attenuated and a crystal of constant cross section shaping technique (CST) grown without any special regulation. The dynamic stability theory of the crystal growth process for all CST is developed on the basis of Lyapunov's dynamic stability theory. Lyapunov's equations for the crystal growth processes follow from fundamental laws. The results of the theory allow the choice of stable regimes for crystal growth by all CST as well as special designs of shapers in TPS. SCG experiments by CZT, VT, and FZT are discussed but the main consideration is given to TPS. Shapers not only allow crystal of very complicated cross section to be grown but provide a special distribution of impurities. A history of TPS is provided later in the chapter, because it can only be described after explanation of the

  15. The shapes of nuclei

    NASA Astrophysics Data System (ADS)

    Bertsch, G. F.

    Gerry Brown initiated some early studies on the coexistence of different nuclear shapes. The subject has continued to be of interest and is crucial for understanding nuclear fission. We now have a very good picture of the potential energy surface with respect to shape degrees of freedom in heavy nuclei, but the dynamics remain problematic. In contrast, the early studies on light nuclei were quite successful in describing the mixing between shapes. Perhaps a new approach in the spirit of the old calculations could better elucidate the character of the fission dynamics and explain phenomena that current theory does not model well.

  16. Patterns of Aberrant Eating among Pre-Adolescent Children in Foster Care

    ERIC Educational Resources Information Center

    Tarren-Sweeney, Michael

    2006-01-01

    The paper reports epidemiological and phenomenological investigations of aberrant eating among 347 pre-adolescent children in court-ordered foster and kinship care, in New South Wales, Australia. A quarter of children displayed clinically significant aberrant eating problems, with no evidence of gender or age effects. Two distinct patterns were…

  17. Simple Demonstration of the Impact of Spherical Aberration on Optical Imaging

    ERIC Educational Resources Information Center

    Escobar, Isabel; Saavedra, Genaro; Pons, Amparo; Martinez-Corral, Manuel

    2008-01-01

    We present an experiment, well adapted for students of introductory optics courses, for the visualization of the impact of spherical aberration in the point spread function of imaging systems. The demonstrations are based on the analogy between the point-spread function of spherically aberrated systems, and the defocused patterns of 1D slit-like…

  18. Aberrant Behaviour of Persons with Developmental Disabilities as a Function of the Characteristics of Training Tasks.

    ERIC Educational Resources Information Center

    Vause, Tricia; Martin, Garry L.; Yu, Dickie

    1999-01-01

    A study used the Assessment of Basic Learning Abilities to assess the abilities of three adults with mental retardation in order to reduce aberrant behavior. There was a higher frequency of aberrant responses during training sessions with training tasks above or below a participant's assessment level on the test. (Contains references.) (CR)

  19. Criteria for admissible values of smooth aberrations for nondiffractive laser beams

    SciTech Connect

    Malashko, Ya I; Khabibulin, V M

    2014-04-28

    We have derived analytical expressions, verified by the methods of numerical simulation, to evaluate the angular divergence of nondiffractive laser beams containing smooth aberrations, i.e., spherical defocusing, astigmatism and toroid. Using these expressions we have formulated the criteria for admissible values of smooth aberrations. (laser applications and other topics in quantum electronics)

  20. Study on the modification of measured wavefront aberration data for customized visual correction

    NASA Astrophysics Data System (ADS)

    Liu, Ming; Zhang, Yong; Zhang, Zhidong; Quan, Wei; An, Li

    2008-12-01

    Wavefront aberration of human eye is an important foundation for customized vision correction. In most current aberrometers, near infrared light is used to measure ocular wavefront aberration, whereas for customized visual correction, wavefront aberration data in visible range are required. With the measured wavefront aberration, corneal topography and eye's axial lengths data, individual eye models for twenty normal human eyes are constructed with the optical design software ZEMAX. Changing the incidence light wavelength and the refractive indexes of eye models, the values of defocus, astigmatism, higher-order aberrations in the measuring wavelength (833nm) and at the most sensitive wavelength of human eye (555nm) are obtained. Average focus shift between 833nm and 555nm is found to be about 0.94D, and different slightly for different individuals; the differences of astigmatism and higher-order aberrations between 833nm and 555nm are quite slight. For customized visual correction, the measured defocus value should be modified, whereas the measured astigmatism and higher-order aberrations could be used directly for the current correction precision. Individual eye model is a useful tool for accurate transformation of the measured wavefront aberration data into the data for visible spectrum.

  1. Eliminating chromatic aberration in Gauss-type lens design using a novel genetic algorithm.

    PubMed

    Fang, Yi-Chin; Tsai, Chen-Mu; Macdonald, John; Pai, Yang-Chieh

    2007-05-01

    Two different types of Gauss lens design, which effectively eliminate primary chromatic aberration, are presented using an efficient genetic algorithm (GA). The current GA has to deal with too many targets in optical global optimization so that the performance is not much improved. Generally speaking, achromatic aberrations have a great relationship with variable glass sets for all elements. For optics whose design is roughly convergent, glass sets for optics will play a significant role in axial and lateral color aberration. Therefore better results might be derived from the optimal process of eliminating achromatic aberration, which could be carried out by finding feasible glass sets in advance. As an alternative, we propose a new optimization process by using a GA and involving theories of geometrical optics in order to select the best optical glass combination. Two Gauss-type lens designs are employed in this research. First, a telephoto lens design is sensitive to axial aberration because of its long focal length, and second, a wide-angle Gauss design is complicated by lateral color aberration at the extreme corners because Gauss design is well known not to deal well with wide-angle problems. Without numbers of higher chief rays passing the element, it is difficult to correct lateral color aberration altogether for the Gauss design. The results and conclusions show that the attempts to eliminate primary chromatic aberrations were successful.

  2. Accommodation with higher-order monochromatic aberrations corrected with adaptive optics

    NASA Astrophysics Data System (ADS)

    Chen, Li; Kruger, Philip B.; Hofer, Heidi; Singer, Ben; Williams, David R.

    2006-01-01

    Higher-order monochromatic aberrations in the human eye cause a difference in the appearance of stimuli at distances nearer and farther from best focus that could serve as a signed error signal for accommodation. We explored whether higher-order monochromatic aberrations affect the accommodative response to 0.5 D step changes in vergence in experiments in which these aberrations were either present as they normally are or removed with adaptive optics. Of six subjects, one could not accommodate at all for steps in either condition. One subject clearly required higher-order aberrations to accommodate at all. The remaining four subjects could accommodate in the correct direction even when higher-order aberrations were removed. No subjects improved their accommodation when higher-order aberrations were corrected, indicating that the corresponding decrease in the depth of field of the eye did not improve the accommodative response. These results are consistent with previous findings of large individual differences in the ability to accommodate in impoverished conditions. These results suggest that at least some subjects can use monochromatic higher-order aberrations to guide accommodation. They also show that some subjects can accommodate correctly when higher-order monochromatic aberrations as well as established cues to accommodation are greatly reduced.

  3. Aberration extraction in the hartmann test by use of spatial filters.

    PubMed

    Robledo-Sánchez, C; Camacho-Basilio, G; Jaramillo-Núñez, A; Gale, D

    1999-06-01

    Using a computer, we generated a set of filters to aid in the retrieval of aberration functions from Hartmanngrams. These filters consist of discrete two-dimensional data points, like the Hartmanngrams themselves, and are orthogonalized by the Gram-Schmidt procedure. The aberration coefficients are obtained by calculation of the scalar product of the Hartmanngram and each orthogonal filter.

  4. Relationship between radiation induced dicentric chromosome aberrations and micronucleus formation in human lymphocytes.

    PubMed

    Hatayoglu, S E; Orta, T

    2007-06-01

    Chromosome damage measured by the chromosome aberration technique is a reliable method to assess the radiation dose absorbed by cells. However, this technique has some disadvantages. Scoring is difficult and requires skill and experience which of these lead low number of cell counts. The micronucleus (MN) technique which also measures chromosome losses has easy scoring criteria leading high numbers of cell counts and therefore holds more statistical power. In this study, the relationship between the results of the micronucleus technique and those obtained by the chromosome aberration technique was investigated after radiation doses of 1Gy, 2Gy, 3Gy and 4Gy to peripheral blood lymphocytes of 3 healthy individuals. Increases in the chromosome damage after radiation were observed in both techniques. When the dicentric aberration frequencies that were measured in the chromosome aberration technique and the micronucleus frequencies were compared, no difference (p > 0.05) between these two independent measures of radiation damage was reported. The relationship between the micronuclei and the free acentric chromosome aberrations measured in the chromosome aberration technique was not significant as well as that between the dicentrics and micronuclei. On the basis of the relationship between the dicentric aberrations and the micronucleus frequencies, the micronucleus technique with an easy and short-term application and with an easy scoring can be used as an alternative to the chromosome aberration technique.

  5. Accuracy of Person-Fit Statistics: A Monte Carlo Study of the Influence of Aberrance Rates

    ERIC Educational Resources Information Center

    St-Onge, Christina; Valois, Pierre; Abdous, Belkacem; Germain, Stephane

    2011-01-01

    Using a Monte Carlo experimental design, this research examined the relationship between answer patterns' aberrance rates and person-fit statistics (PFS) accuracy. It was observed that as the aberrance rate increased, the detection rates of PFS also increased until, in some situations, a peak was reached and then the detection rates of PFS…

  6. Mechanisms for the induction of gastric cancer by Helicobacter pylori infection: aberrant DNA methylation pathway.

    PubMed

    Maeda, Masahiro; Moro, Hiroshi; Ushijima, Toshikazu

    2017-03-01

    Multiple pathogenic mechanisms by which Helicobacter pylori infection induces gastric cancer have been established in the last two decades. In particular, aberrant DNA methylation is induced in multiple driver genes, which inactivates them. Methylation profiles in gastric cancer are associated with specific subtypes, such as microsatellite instability. Recent comprehensive and integrated analyses showed that many cancer-related pathways are more frequently altered by aberrant DNA methylation than by mutations. Aberrant DNA methylation can even be present in noncancerous gastric mucosae, producing an "epigenetic field for cancerization." Mechanistically, H. pylori-induced chronic inflammation, but not H. pylori itself, plays a direct role in the induction of aberrant DNA methylation. The expression of three inflammation-related genes, Il1b, Nos2, and Tnf, is highly associated with the induction of aberrant DNA methylation. Importantly, the degree of accumulated aberrant DNA methylation is strongly correlated with gastric cancer risk. A recent multicenter prospective cohort study demonstrated the utility of epigenetic cancer risk diagnosis for metachronous gastric cancer. Suppression of aberrant DNA methylation by a demethylating agent was shown to inhibit gastric cancer development in an animal model. Induction of aberrant DNA methylation is the major pathway by which H. pylori infection induces gastric cancer, and this can be utilized for translational opportunities.

  7. Aberrance Detection Powers of the BW and Person-Fit Indices

    ERIC Educational Resources Information Center

    Huang, Tsai-Wei

    2012-01-01

    The study compared the aberrance detection powers of the BW person-fit indices with other group-based indices (SCI, MCI, NCI, and Wc&Bs) and item response theory based (IRT-based) indices (OUTFITz, INFITz, ECI2z, ECI4z, and lz). Four kinds of comparative conditions, including content category (CC), types of aberrance (AT), severity of…

  8. Bayesian Procedures for Identifying Aberrant Response-Time Patterns in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Guo, Fanmin

    2008-01-01

    In order to identify aberrant response-time patterns on educational and psychological tests, it is important to be able to separate the speed at which the test taker operates from the time the items require. A lognormal model for response times with this feature was used to derive a Bayesian procedure for detecting aberrant response times.…

  9. Effects of escape to alone versus escape to enriched environments on adaptive and aberrant behavior.

    PubMed Central

    Golonka, Z; Wacker, D; Berg, W; Derby, K M; Harding, J; Peck, S

    2000-01-01

    Escape-maintained aberrant behavior may be influenced by two outcomes: (a) a break from the activity and (b) subsequent access to preferred activities. To assess this hypothesis, a treatment was developed that analyzed response allocation across two break options: break alone and break with access to preferred social activities. The break with preferred activities decreased aberrant behavior and increased appropriate behavior. PMID:10885532

  10. Aberration correction of double-sided telecentric zoom lenses using lens modules.

    PubMed

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

    2014-09-20

    A systematic approach for the aberration design of a four-component double-sided telecentric zoom lens system is presented. The Gaussian structure of the zoom system is specified previously which means the powers and movements of components are known. Each component is treated as a lens module during the design stage with specified first-order properties and third-order aberration targets. The third-order aberration targets of the first component are determined by minimizing the whole aberrations of the zoom lens system using a genetic algorithm (GA). And the aberration targets of components behind are determined by reoptimization with already fixed structures of previous components. Mean pupil spherical aberration of every component in every zoom position is adopted in the objective function to control high-order aberrations. The thin lens structure of each component can be determined from their first-order properties and aberration targets. After lens thickening and reoptimization, the zoom lens system can finally be determined.

  11. [A case of chronic pancreatitis occurring in gastric aberrant pancreas poorly distinguishable from gastric aberrant pancreas ductal carcinoma].

    PubMed

    Ogawa, Sayaka; Miyaoka, Youichi; Fujiwara, Aya; Tsukano, Kousuke; Kotani, Satoshi; Yamanouchi, Satoshi; Kusunoki, Ryusaku; Ito, Satoko; Fujishiro, Hirofumi; Kohge, Nariaki; Onuma, Hideyuki

    2015-11-01

    A man in his 40s was referred to our hospital with abdominal pain. A gastric submucosal tumor (SMT) was diagnosed nine years previously, but the patient was lost to follow-up. Upon our evaluation, the SMT had enlarged, as demonstrated by esophagogastroduodenoscopy and abdominal computed tomography. Endoscopic ultrasonography revealed a hypoechoic and isoechoic mosaic mass, which primarily occupied the third and fourth layers of the gastric wall. Aspiration cytodiagnosis was performed, the results of which led to a suspicion of adenocarcinoma arising from gastric ectopic pancreas. Next, we conducted segmental gastrectomy. Pathological examination showed adiponecrosis, a pancreatic stone, chronic inflammatory cell infiltration, and fibrosis. Thus, the patient was diagnosed with chronic pancreatitis occurring in a gastric aberrant pancreas.

  12. Transitionality in addiction: A "temporal continuum" hypotheses involving the aberrant motivation, the hedonic dysregulation, and the aberrant learning.

    PubMed

    Patrono, Enrico; Gasbarri, Antonella; Tomaz, Carlos; Nishijo, Hisao

    2016-08-01

    Addiction is a chronic compulsion and relapsing disorder. It involves several brain areas and circuits, which encode vary functions such as reward, motivation, and memory. Drug addiction is defined as a "pathological pattern of use of a substance", characterized by the loss of control on drug-taking-related behaviors, the pursuance of those behaviors even in the presence of negative consequences, and a strong motivated activity to assume substances. Three different theories guide experimental research on drug addiction. Each of these theories consider singles features, such as an aberrant motivation, a hedonic dysregulation, and an aberrant habit learning as the main actor to explain the entire process of the addictive behaviors. The major goal of this study is to present a new hypotheses of transitionality from a controlled use to abuse of addictive substances trough the overview of the three different theories, considering all the single features of each single theory together on the same "temporal continuum" from use to abuse of addictive substances. Recently, it has been suggested that common neural systems may be activated by natural and pharmacological stimuli, raising the hypotheses that binge-eating disorders could be considered as addictive behaviors. The second goal of this study is to present evidences in order to highlight a possible psycho-bio-physiological superimposition between drug and "food addiction". Finally, interesting questions are brought up starting from last findings about a theoretical/psycho-bio-physiological superimposition between drug and "food addiction" and their possibly same transitionality along the same "temporal continuum" from use to abuse of addictive substances in order to investigate new therapeutic strategies based on new therapeutic strategies based on the individual moments characterizing the transition from the voluntary intake of substances to the maladaptive addictive behavior.

  13. Aspherical surfaces design for extreme ultraviolet lithographic objective with correction of thermal aberration

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Li, Yanqiu

    2016-09-01

    At present, few projection objectives for extreme ultraviolet (EUV) lithography pay attention to correct thermal aberration in optical design phase, which would lead to poor image quality in a practical working environment. We present an aspherical modification method for helping the EUV lithographic objective additionally correct the thermal aberration. Based on the thermal aberration and deformation predicted by integrated optomechanical analysis, the aspherical surfaces in an objective are modified by an iterative algorithm. The modified aspherical surfaces could correct the thermal aberration and maintain the initial high image quality in a practical working environment. A six-mirror EUV lithographic objective with 0.33-numerical aperture is taken as an example to illustrate the presented method. The results show that the thermal aberration can be corrected effectively, and the image quality of the thermally deformed system is improved to the initial design level, which proves the availability of the method.

  14. Shaping Crystals using Electrophoresis

    NASA Astrophysics Data System (ADS)

    Palacci, Jeremie; Mackiewicz, Kristian

    2016-11-01

    Electrophoresis is size and shape independent as stressed by Morrison in his seminal paper. Here we present an original approach to reshape colloidal crystals using an electric field as a carving tool.

  15. Silicon Carbide Shapes.

    DTIC Science & Technology

    Free-standing silicon carbide shapes are produced by passing a properly diluted stream of a reactant gas, for example methyltrichlorosilane, into a...reaction chamber housing a thin walled, hollow graphite body heated to 1300-1500C. After the graphite body is sufficiently coated with silicon carbide , the...graphite body is fired, converting the graphite to gaseous CO2 and CO and leaving a silicon carbide shaped article remaining.

  16. Laser shaping of cartilage

    NASA Astrophysics Data System (ADS)

    Sobol, Emil N.; Bagratashvili, Victor N.; Omelchenko, Alexander I.; Sviridov, Alexander P.; Helidonis, Emmanuel S.; Kavvalos, George; Christodoulou, P. N.; Naoumidi, I.; Velegrakis, G.; Ovchinnikov, Yuriy M.; Shechter, A.

    1994-09-01

    The carbon dioxide laser has been used for the first time to change the cartilage's shape. After the laser irradiation the cartilage has the tendency to retain its new form. Different types of laser modified cartilage structures were studied. The inferred physical mechanism for cartilage shaping using the stresses relaxation process is presented. The clinical significance of the results for corrective laser surgery is discussed.

  17. Universality of fragment shapes

    PubMed Central

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-01-01

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism. PMID:25772300

  18. On Characterizing Particle Shape

    NASA Technical Reports Server (NTRS)

    Ennis, Bryan J.; Rickman, Douglas; Rollins, A. Brent; Ennis, Brandon

    2014-01-01

    It is well known that particle shape affects flow characteristics of granular materials, as well as a variety of other solids processing issues such as compaction, rheology, filtration and other two-phase flow problems. The impact of shape crosses many diverse and commercially important applications, including pharmaceuticals, civil engineering, metallurgy, health, and food processing. Two applications studied here include the dry solids flow of lunar simulants (e.g. JSC-1, NU-LHT-2M, OB-1), and the flow properties of wet concrete, including final compressive strength. A multi-dimensional generalized, engineering method to quantitatively characterize particle shapes has been developed, applicable to both single particle orientation and multi-particle assemblies. The two-dimension, three dimension inversion problem is also treated, and the application of these methods to DEM model particles will be discussed. In the case of lunar simulants, flow properties of six lunar simulants have been measured, and the impact of particle shape on flowability - as characterized by the shape method developed here -- is discussed, especially in the context of three simulants of similar size range. In the context of concrete processing, concrete construction is a major contributor to greenhouse gas production, of which the major contributor is cement binding loading. Any optimization in concrete rheology and packing that can reduce cement loading and improve strength loading can also reduce currently required construction safety factors. The characterization approach here is also demonstrated for the impact of rock aggregate shape on concrete slump rheology and dry compressive strength.

  19. Universality of fragment shapes

    NASA Astrophysics Data System (ADS)

    Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

    2015-03-01

    The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

  20. The Visual Impact of Zernike and Seidel Forms of Monochromatic Aberrations

    PubMed Central

    Cheng, Xu; Bradley, Arthur; Ravikumar, Sowmya; Thibos, Larry N.

    2010-01-01

    Purpose To examine the impact on visual acuity of different aberrations modes (e.g. coma, astigmatism, spherical aberration (SA)) and different aberration basis functions (Zernike or Seidel). Methods Computational optics was used to generate retinal images degraded by either the Zernike or Seidel forms of 2nd through 4th order aberrations for an eye with a 5mm pupil diameter. High contrast, photopic visual acuity was measured using method of constant stimuli for letters displayed on a computer-controlled, linearized, quasi-monochromatic (λ=556 nm) display. Results Minimum angle of resolution (MAR) varied linearly with the magnitude (root mean square error, RMS) of all modes of aberration. The impact of individual Zernike lower and higher order aberrations (HOAs) varied significantly with mode, e.g. arc minutes of MAR/micron of RMS slopes varied from 7 (spherical defocus) to 0.5 (quadrafoil). Seidel forms of these aberrations always had a smaller visual impact. Notably, Seidel spherical aberration (SA) had 1/17th the impact of Zernike SA with the same wavefront variance, and about 1/4th the impact of Zernike SA with matching levels of r4 wavefront error. With lower order components removed, HOAs near the center of the Zernike pyramid do not have a large visual impact. Conclusions The majority of the visual impact of high levels of 4th order Zernike aberrations can be attributed to the 2nd order terms within these polynomials. Therefore, the impact of SA can be minimized by balancing it with a defocus term that flattens the central wavefront (paraxial focus) or maximizes the area of the pupil with a flat wavefront. Over this wide range of aberration types and levels, image quality metrics based upon the PSF and OTF can predict VA as reliably as VA measures can predict retests of VA, and thus such metrics may become valuable predictors of both VA and, via optimization, refractions. PMID:20351600

  1. Aberrant Type I Interferon Regulation in Autoimmunity: Opposite Directions in MS and SLE, Shaped by Evolution and Body Ecology

    PubMed Central

    Reder, Anthony T.; Feng, Xuan

    2013-01-01

    Studying the action of mechanisms of type I interferon (IFN) provides the insight to elucidate the cause and therapy for autoimmune diseases. There are high IFN responses in some diseases such as connective tissue diseases, but low responses in multiple sclerosis. Distinct IFN features lead us to understand pathology of a spectrum of autoimmune diseases and help us to search genetic changes, gene expression, and biomarkers for diagnosis, disease progression, and treatment response. PMID:24062747

  2. Optical aberrations, retinal image quality and eye growth: Experimentation and modeling

    NASA Astrophysics Data System (ADS)

    Tian, Yibin

    2007-12-01

    Retinal image quality is important for normal eye growth. Optical aberrations are of interest for two reasons: first, they degrade retinal images; second, they might provide some cues to defocus. Higher than normal ocular aberrations have been previously associated with human myopia. However, these studies were cross-sectional in design, and only reported aberrations in terms of root mean square (RMS) errors of Zernike coefficients, a poor metric of optical quality. This dissertation presents results from investigations of ocular optical aberrations, retinal image quality and eye growth in chicks and humans. A number of techniques were utilized, including Shack-Hartmann aberrometry, high-frequency A-scan ultrasonography, ciliary nerve section (CNX), photorefractive keratectomy (PRK) as well as computer simulations and modeling. A technique to extract light scatter information from Shack-Hartmann images was also developed. The main findings of the dissertation are summarized below. In young chicks, most ocular aberrations decreased with growth in both normal and CNX eyes, and there were diurnal fluctuations in some aberrations. Modeling suggested active reduction in higher order aberrations (HOAs) during early development. Although CNX eyes manifested greater than normal HOAs, they showed near normal growth. Retinal image degradation varied greatly among individual eyes post-PRK in young chicks. Including light scatter information into analyses of retinal image quality better estimated the latter. Albino eyes showed more severe retinal image degradation than normal eyes, due to increased optical aberrations and light scatter, but their growth was similar to those of normal eyes, implying that they are relatively insensitive to retina image quality. Although the above results questioned the influence of optical aberrations on early ocular growth, some optical quality metrics, derived from optical aberrations data, could predict how much the eyes of young chicks

  3. In-line-focus monitoring technique using lens aberration effect

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tomohiko; Sawano, Toshio; Yao, Teruyoshi; Kobayashi, Katsuyoshi; Asai, Satoru

    2005-05-01

    Process windows have become narrower as nano-processing technology has advanced. The semiconductor industry, faced with this situation, has had to impose extremely severe tool controls. Above all, with the advent of 90-nm device production, demand has arisen for strict levels of control that exceed the machine specifications of ArF exposure systems. Consequently, high-accuracy focus control and focus monitoring techniques for production wafers will be necessary in order for this to be achieved for practical use. Focus monitoring techniques that measure pattern placement errors and resist features using special reticle and mark have recently been proposed. Unfortunately, these techniques have several disadvantages. They are unable to identify the direction of a focus error, and there are limits on the illumination conditions. Furthermore, they require the use of a reticle that is more expensive than normal and they suffer from a low level of measurement accuracy. To solve these problems, the authors examined methods of focus control and focus error measurement for production wafers that utilize the lens aberration of the exposure tool system. The authors call this method FMLA (focus monitoring using lens aberration). In general, astigmatism causes a difference in the optimum focal point between the horizontal and vertical patterns in the same image plane. If a focus error occurs, regardless of the reason, a critical dimension (CD) difference arises between the sparse horizontal and vertical lines. In addition, this CD difference decreases or increases monotonously with the defocus value. That is to say, it is possible to estimate the focus errors to measure the vertical and horizontal line CD formed by exposure tool with astigmatism. In this paper, the authors examined the FMLA technique using astigmatism. First, focus monitoring accuracy was investigated. Using normal scholar type simulation, FMLA was able to detect a 32.3-nm focus error when 10-mλ astigmatism was

  4. Technical Seminar "Shape Memory Alloys"

    NASA Video Gallery

    Shape memory alloys are a unique group of materials that remember their original shape and return to that shape after being strained. How could the aerospace, automotive, and energy exploration ind...

  5. Influence of Operator's Experience on the Shaping Ability of Protaper Universal and Waveone Systems: A Comparative Study on Simulated Root Canals

    PubMed Central

    Troiano, Giuseppe; Dioguardi, Mario; Cocco, Armando; Giannatempo, Giovanni; Laino, Luigi; Ciavarella, Domenico; Berutti, Elio; Lo Muzio, Lorenzo

    2016-01-01

    Objective: To assess the influence of operator experience on: shaping and centering ability, mean preparation time and presence of canal aberrations of ProTaper Universal and WaveOne systems on simulated root canals. Materials and Methods: Sixty S-shaped canals in resin blocks were assigned to four groups (n=15 for each group). Group1 (Experienced operator, ProTaper), Group2 (Experienced operator, WaveOne), Group3 (Inexperienced operator, ProTaper), Group4 (Inexperienced operator, WaveOne). Photographic method was used to record pre- and post-instrumentations images. After superimposition, it has been evaluated presence of canal aberrations and differences in shaping and centering ability between groups. Results: WaveOne system produced a lower amount of canal aberrations both in the hand of expert than inexpert operators. However, a WaveOne instrument breakage occurred in the hands of an inexperienced operator. No differences have been found in the evaluation of shaping ability with both systematics. Operator’s experience doesn't influence the shaping ability of ProTaper and WaveOne systems. Conclusion: Experience factor could influence the centering ability in the use of both the systematics. However, WaveOne Primary reduce the mean preparation time and the presence of canal aberrations. PMID:27843508

  6. Shape memory polymer medical device

    DOEpatents

    Maitland, Duncan; Benett, William J.; Bearinger, Jane P.; Wilson, Thomas S.; Small, IV, Ward; Schumann, Daniel L.; Jensen, Wayne A.; Ortega, Jason M.; Marion, III, John E.; Loge, Jeffrey M.

    2010-06-29

    A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

  7. Balanced diffraction aberrations, independent of the observation point: application to a tilted dielectric plate.

    PubMed

    Sheppard, Colin J R

    2013-10-01

    Balancing of Zernike aberrations breaks down if the defocus term is large enough that the condition (z/λ)≪2/[π(NA)⁴] is not satisfied. A modified Zernike aberration expansion, based on the Zernike aberrations, is developed that accurately includes axial displacement as a low-order term, even for large displacements. This expansion can be used to analyze aberrations for on-axis illumination of a high numerical aperture system. But more importantly, for systems of moderate numerical aperture it allows balanced aberration coefficients to be determined independent of the assumption of a particular reference point. The approach is applied to the case of a tilted dielectric plate. An exact expression is given for the wave front aberration, valid for both large angles of tilt and high beam convergence angles, that is independent of observation distance. Analytical expressions for the third- and fifth-order aberration coefficients are derived. Expressions are given for expansion of multiple-angle power series terms into Zernike polynomials.

  8. Study on intra-ocular lens aberration measurement in-air

    NASA Astrophysics Data System (ADS)

    Wang, Yuanyuan; Chen, Jiaojie; Fen, Haihua; Hu, Chuan; Li, Yiyi

    2010-10-01

    In clinical ophthalmology, the wavefront aberration of human eyes is expressed by Zernike polynomial after cataract surgery and intraocular lens implantation, the human eyes aberration will change. The problem of objective evaluation of wavefront aberration introduced by the Intra-ocular (IOL) in-vivo remains unsolved. This paper introduced the measurement principal of IOL wavefront aberration with expression by Zernike polynominal in air. A Hartmann-Shack wavefront sensor system was constructed to measure the wavefront of IOL and to get the corresponding grid patterns. After a series of computer image processing steps, 7th order with 35 items Zernike coefficients was obtained. The IOL of 20.0D power was measured 5 times by this system to get the spherical aberration about 6.73+/-0.02μm, demonstrating the good repeatability of the system. Ten IOLs with the same 20.0D power but difference in surface curvature were chosen for measurement. The spherical aberration observed were in the range of 2.74μm-11.26μm. These results are valuable for the optical design of IOLs and the aberration analysis of human eyes post-operation.

  9. Influence of atmospheric turbulence on the energy focusability of Gaussian beams with spherical aberration

    NASA Astrophysics Data System (ADS)

    Deng, Jinping; Ji, Xiaoling

    2014-05-01

    By using the four-dimensional (4D) computer code of the time-dependent propagation of laser beams through atmospheric turbulence, the influence of atmospheric turbulence on the energy focusability of Gaussian beams with spherical aberration is studied in detail, where the mean-squared beam width, the power in the bucket (PIB), the β parameter and the energy Strehl ratio are taken as the characteristic parameters. It is shown that turbulence results in beam spreading, and the effect of spherical aberration on the beam spreading decreases due to turbulence. Gaussian beams with negative spherical aberration are more affected by turbulence than those with positive spherical aberration. For the negative spherical aberration case, the focus position moves to the source plane due to turbulence. It is mentioned that the influence of turbulence on the energy focusability defined by a certain energy (i.e. PIB = 63%) is very heavy when the negative spherical aberration is very heavy. On the other hand, the influence of turbulence on the energy focusability defined by the energy within a given bucket radius (i.e. mean-squared beam width) is heaviest when a certain negative spherical aberration coefficient is adopted.

  10. Aberrant DNA methylation occurs in colon neoplasms arising in the azoxymethane colon cancer model

    PubMed Central

    Borinstein, Scott C.; Conerly, Melissa; Dzieciatkowski, Slavomir; Biswas, Swati; Washington, M. Kay; Trobridge, Patty; Henikoff, Steve; Grady, William M.

    2010-01-01

    Mouse models of intestinal tumors have advanced our understanding of the role of gene mutations in colorectal malignancy. However, the utility of these systems for studying the role of epigenetic alterations in intestinal neoplasms remains to be defined. Consequently, we assessed the role of aberrant DNA methylation in the azoxymethane (AOM) rodent model of colon cancer. AOM induced tumors display global DNA hypomethylation, which is similar to human colorectal cancer. We next assessed the methylation status of a panel of candidate genes previously shown to be aberrantly methylated in human cancer or in mouse models of malignant neoplasms. This analysis revealed different patterns of DNA methylation that were gene specific. Zik1 and Gja9 demonstrated cancer-specific aberrant DNA methylation, whereas, Cdkn2a/p16, Igfbp3, Mgmt, Id4, and Cxcr4 were methylated in both the AOM tumors and normal colon mucosa. No aberrant methylation of Dapk1 or Mlt1 was detected in the neoplasms, but normal colon mucosa samples displayed methylation of these genes. Finally, p19Arf, Tslc1, Hltf, and Mlh1 were unmethylated in both the AOM tumors and normal colon mucosa. Thus, aberrant DNA methylation does occur in AOM tumors, although the frequency of aberrantly methylated genes appears to be less common than in human colorectal cancer. Additional studies are necessary to further characterize the patterns of aberrantly methylated genes in AOM tumors. PMID:19777566

  11. Influence of wavefront aberration on the imaging performance of the solar grating spectrometer.

    PubMed

    Zheng, L H; Rao, C H; Gu, N T; Huang, L H; Qiu, Q

    2016-01-11

    The solar grating spectrometer is an important tool to study the thermodynamic properties of the solar atmosphere with different height distribution, but its imaging performance will be degraded by the wavefront aberration. On the other hand, narrow slit of the grating spectrometer will filter the wavefront aberration to a certain extent. In this paper, the mathematical relation between the wavefront aberration and the imaging performance of the grating spectrometer is derived. The numerical simulation is performed and is validated by the experiment. The results demonstrate that: The influence of the wavefront aberration with the different types and magnitudes on the spectral resolution and the energy utilization is different. The influence of the different slits on the wavefront aberrations is different. Generally, the smaller the slit is, the better the spectral resolution is. However, this is not true for the low-frequency dominated aberration, e.g. the defocus, since its low frequency will also be blocked by the narrow slit. If the influence of the filter slit on the wavefront aberration cannot be taken into account, it will lead to adaptive optics over-compensation.

  12. Eigenfunction analysis of stochastic backscatter for characterization of acoustic aberration in medical ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Varslot, Trond; Krogstad, Harald; Mo, Eirik; Angelsen, Bjørn A.

    2004-06-01

    Presented here is a characterization of aberration in medical ultrasound imaging. The characterization is optimal in the sense of maximizing the expected energy in a modified beamformer output of the received acoustic backscatter. Aberration correction based on this characterization takes the form of an aberration correction filter. The situation considered is frequently found in applications when imaging organs through a body wall: aberration is introduced in a layer close to the transducer, and acoustic backscatter from a scattering region behind the body wall is measured at the transducer surface. The scattering region consists of scatterers randomly distributed with very short correlation length compared to the acoustic wavelength of the transmit pulse. The scatterer distribution is therefore assumed to be δ correlated. This paper shows how maximizing the expected energy in a modified beamformer output signal naturally leads to eigenfunctions of a Fredholm integral operator, where the associated kernel function is a spatial correlation function of the received stochastic signal. Aberration characterization and aberration correction are presented for simulated data constructed to mimic aberration introduced by the abdominal wall. The results compare well with what is obtainable using data from a simulated point source.

  13. Breaking the spherical and chromatic aberration barrier in transmission electron microscopy.

    PubMed

    Freitag, B; Kujawa, S; Mul, P M; Ringnalda, J; Tiemeijer, P C

    2005-02-01

    Since the invention of transmission electron microscopy (TEM) in 1932 (Z. Physik 78 (1932) 318) engineering improvements have advanced system resolutions to levels that are now limited only by the two fundamental aberrations of electron lenses; spherical and chromatic aberration (Z. Phys. 101 (1936) 593). Since both aberrations scale with the dimensions of the lens, research resolution requirements are pushing the designs to lenses with only a few mm space in the pole-piece gap for the specimen. This is in conflict with the demand for more and more space at the specimen, necessary in order to enable novel techniques in TEM, such as He-cooled cryo electron microscopy, 3D-reconstruction through tomography (Science 302 (2003) 1396) TEM in gaseous environments, or in situ experiments (Nature 427 (2004) 426). All these techniques will only be able to achieve Angstrom resolution when the aberration barriers have been overcome. The spherical aberration barrier has recently been broken by introducing spherical aberration correctors (Nature 392 (1998) 392, 418 (2002) 617), but the correction of the remaining chromatic aberrations have proved to be too difficult for the present state of technology (Optik 57 (1980) 73). Here we present an alternative and successful method to eliminate the chromatic blur, which consists of monochromating the TEM beam (Inst. Phys. Conf. Ser. 161 (1999) 191). We show directly interpretable resolutions well below 1A for the first time, which is significantly better than any TEM operating at 200 KV has reached before.

  14. Aberrant and alternative splicing in skeletal system disease.

    PubMed

    Fan, Xin; Tang, Liling

    2013-10-01

    The main function of skeletal system is to support the body and help movement. A variety of factors can lead to skeletal system disease, including age, exercise, and of course genetic makeup and expression. Pre-mRNA splicing plays a crucial role in gene expression, by creating multiple protein variants with different biological functions. The recent studies show that several skeletal system diseases are related to pre-mRNA splicing. This review focuses on the relationship between pre-mRNA splicing and skeletal system disease. On the one hand, splice site mutation that leads to aberrant splicing often causes genetic skeletal system disease, like COL1A1, SEDL and LRP5. On the other hand, alternative splicing without genomic mutation may generate some marker protein isoforms, for example, FN, VEGF and CD44. Therefore, understanding the relationship between pre-mRNA splicing and skeletal system disease will aid in uncovering the mechanism of disease and contribute to the future development of gene therapy.

  15. Astrocyte Hypertrophy Contributes to Aberrant Neurogenesis after Traumatic Brain Injury

    PubMed Central

    Robinson, Clark; Apgar, Christopher; Shapiro, Lee A.

    2016-01-01

    Traumatic brain injury (TBI) is a widespread epidemic with severe cognitive, affective, and behavioral consequences. TBIs typically result in a relatively rapid inflammatory and neuroinflammatory response. A major component of the neuroinflammatory response is astrocytes, a type of glial cell in the brain. Astrocytes are important in maintaining the integrity of neuronal functioning, and it is possible that astrocyte hypertrophy after TBIs might contribute to pathogenesis. The hippocampus is a unique brain region, because neurogenesis persists in adults. Accumulating evidence supports the functional importance of these newborn neurons and their associated astrocytes. Alterations to either of these cell types can influence neuronal functioning. To determine if hypertrophied astrocytes might negatively influence immature neurons in the dentate gyrus, astrocyte and newborn neurons were analyzed at 30 days following a TBI in mice. The results demonstrate a loss of radial glial-like processes extending through the granule cell layer after TBI, as well as ectopic growth and migration of immature dentate neurons. The results further show newborn neurons in close association with hypertrophied astrocytes, suggesting a role for the astrocytes in aberrant neurogenesis. Future studies are needed to determine the functional significance of these alterations to the astrocyte/immature neurons after TBI. PMID:27274873

  16. Aberrant seasonal variations of platelet serotonin uptake in endogenous depression.

    PubMed

    Malmgren, R; Aberg-Wistedt, A; Mårtensson, B

    1989-02-15

    The serotonin uptake in platelets of 120 healthy volunteers and 64 endogenously depressed patients was investigated over a 2-year period. In healthy individuals, Km exhibited a significant seasonal rhythm during the bright half of the year. The seasonal rhythm of Vmax assumes the form of a sine curve, with nadir values at the vernal and autumn equinoxes and peak values at the winter and summer solstices. Km in patients was higher than in controls in February and October, and the seasonal variation of Km differed between patients and controls. The monthly mean values of Vmax in patients were, as a rule, lower than corresponding values in controls, but significantly so only in December. Patients had higher Vmax than controls in October and November, and the seasonal variation of Vmax in patients differed from that of controls. The results suggest that Km, a measure of the affinity of the serotonin uptake site, may be subject to photoperiodic regulation in healthy individuals. The annual variation in uptake site densities, as judged by the changes in Vmax, are probably generated by an endogenous superior oscillator. The aberrant uptake kinetics found in the endogenously depressed patients may reflect seasonal susceptibility to the disorder and/or altered serotonergic rhythmicity.

  17. Aberrations and focusability in large solid-state-laser systems

    SciTech Connect

    Simmons, W.W.

    1981-01-01

    Solid state lasers for fusion experiments must reliably deliver maximum power to small (approximately .5 mm) targets from stand-off focal distances of 1 m or more. This requirement places stringent limits upon the optical quality of the several major components - amplifiers, Faraday isolators, spatial filters - in each amplifier train. Residual static aberrations in optical components are transferred to the beam as it traverses the optical amplifier chain. Although individual components are typically less than lambda/20 for components less than 10 cm clear aperture; and less than lambda/10 for components less than 20 cm clear aperture; the large number of such components in optical series results in a wavefront error that may exceed one wave for modern solid state lasers. For pulse operation, the focal spot is additionally broadened by intensity dependent nonlinearities. Specific examples of the performance of large aperture components will be presented within the context of the Argus and Shiva laser systems, which are presently operational at Lawrence Livermore National Laboratory. Design requirements upon the larger aperture Nova laser components, up to 74 cm in clear aperture, will also be discussed; these pose a significant challenge to the optical industry.

  18. Generalized formulas for ray-tracing and longitudinal spherical aberration.

    PubMed

    Elagha, Hassan A

    2017-03-01

    In this work, we generalize the paraxial ray-tracing formulas to include nonparaxial rays. For a refracting (reflecting) spherical surface, a new single meridional formula is derived. This formula can be easily reduced to a paraxial formula. It can also be applied to any aspheric (or general) surface with a known equation. Also, a new exact ray-tracing procedure for a centered system of spherical surfaces is derived. In this procedure, we apply just two simple equations for each surface of the system, which, to the best of our knowledge, makes it the shortest analytical ray-tracing technique ever. This procedure can be applied in some other applications. For example, it can be reduced to a new single paraxial formula that can be easily used to trace a paraxial ray propagating through a system of spherical surfaces. Also, it is applied to derive an exact meridional formula for both thick and thin lenses that can also be reduced to a new paraxial formula different from the Gaussian one. These results led us to easily derive an exact formula for the longitudinal spherical aberration for both thick and thin lenses and also for a single refracting (reflecting) spherical surface. Numerical examples are provided and discussed.

  19. Aberrant expression of homeobox gene SIX1 in Hodgkin lymphoma

    PubMed Central

    Nagel, Stefan; Meyer, Corinna; Kaufmann, Maren; Drexler, Hans G.; MacLeod, Roderick A.F.

    2015-01-01

    In Hodgkin lymphoma (HL) we recently identified deregulated expression of homeobox genes MSX1 and OTX2 which are physiologically involved in development of the embryonal neural plate border region. Here, we examined in HL homeobox gene SIX1 an additional regulator of this embryonal region mediating differentiation of placodal precursors. SIX1 was aberrantly activated in 12 % of HL patient samples in silico, indicating a pathological role in a subset of this B-cell malignancy. In addition, SIX1 expression was detected in HL cell lines which were used as models to reveal upstream factors and target genes of this basic developmental regulator. We detected increased copy numbers of the SIX1 locus at chromosome 14q23 correlating with enhanced expression while chromosomal translocations were absent. Moreover, comparative expression profiling data and pertinent gene modulation experiments indicated that the WNT-signalling pathway and transcription factor MEF2C regulate SIX1 expression. Genes encoding the transcription factors GATA2, GATA3, MSX1 and SPIB – all basic lymphoid regulators - were identified as targets of SIX1 in HL. In addition, cofactors EYA1 and TLE4, respectively, contrastingly mediated activation and suppression of SIX1 target gene expression. Thus, the protein domain interfaces may represent therapeutic targets in SIX1-positive HL subsets. Collectively, our data reveal a gene regulatory network with SIX1 centrally deregulating lymphoid differentiation and support concordance of lymphopoiesis/lymphomagenesis and developmental processes in the neural plate border region. PMID:26473286

  20. Aberrant genomic imprinting in rhesus monkey embryonic stem cells.

    PubMed

    Fujimoto, Akihisa; Mitalipov, Shoukhrat M; Kuo, Hung-Chih; Wolf, Don P

    2006-03-01

    Genomic imprinting involves modification of a gene or a chromosomal region that results in the differential expression of parental alleles. Disruption or inappropriate expression of imprinted genes is associated with several clinically significant syndromes and tumorigenesis in humans. Additionally, abnormal imprinting occurs in mouse embryonic stem cells (ESCs) and in clonally derived animals. Imprinted gene expression patterns in primate ESCs are largely unknown, despite the clinical potential of the latter in the cell-based treatment of human disease. Because of the possible implications of abnormal gene expression to cell or tissue replacement therapies involving ESCs, we examined allele specific expression of four imprinted genes in the rhesus macaque. Genomic and complementary DNA from embryos and ESC lines containing useful single nucleotide polymorphisms were subjected to polymerase chain reaction-based amplification and sequence analysis. In blastocysts, NDN expression was variable indicating abnormal or incomplete imprinting whereas IGF2 and SNRPN were expressed exclusively from the paternal allele and H19 from the maternal allele as expected. In ESCs, both NDN and SNRPN were expressed from the paternal allele while IGF2 and H19 showed loss of imprinting and biallelic expression. In differentiated ESC progeny, these expression patterns were maintained. The implications of aberrant imprinted gene expression to ESC differentiation in vitro and on ESC-derived cell function in vivo after transplantation are unknown.

  1. Histomorphology of aberrant crypt foci in colorectal carcinoma.

    PubMed

    Norlida, A Ojep; Phang, Koon Seng

    2010-12-01

    Colorectal carcinogenesis is a complex multistep process that includes changes in histomorphological appearance of the colonic mucosa and changes at molecular level. Aberrant crypt foci (ACF) was first described by Bird in 1987 on examination of methylene-blue-stained colonic mucosa of azoxymethane-treated mice under light microscopy. Since then ACF was considered as the earliest preneoplastic change that can be seen in the colonic mucosa. The aim of this study was to look at the histomorphology and distribution of ACF in colorectal carcinoma. 50 formalin-fixed archival colectomy specimens for colorectal carcinoma were examined under light microscopy after staining with 0.2% methylene blue. ACF was identified by larger and darker crypts with thickened epithelium, and often elevated from adjacent normal mucosa. ACF was found in 41 of 50 colectomy specimens examined. There were 328 ACF consisting of 36 (11.0%) ACF without hyperplasia or dysplasia, 263 (80.2%) ACF with hyperplasia and 29 (8.8%) ACF with dysplasia. Of these 29 ACF with dysplasia, 25 showed low grade dysplasia and four high grade dysplasia. The density of ACF was higher in the left colon, those older than 65 years of age and among males but these findings were statistically not significant. The crypt multiplicity of hyperplastic ACF (30.149, SD 28.395) was larger than dysplastic ACF (20.613, SD 40.128). The spectrum of histological changes observed probably represent the evolution of ACF in colorectal carcinogenesis.

  2. Aberrant driving behaviors: a study of drivers in Beijing.

    PubMed

    Shi, Jing; Bai, Yun; Ying, Xiwen; Atchley, Paul

    2010-07-01

    The addition of massive numbers of new drivers with varied driving experience to roads in China suggests it is important to understand the nature of aberrant driving behaviors for this new set of drivers. A paper-based and an Internet survey were administered. Factor analysis produced a five-factor structure for each survey. The distinction between violations and errors indicated in previous studies was confirmed. The violations included emotional violations, risky violations and self-willed violations, and the errors included inexperience errors and distraction errors. In contrast to previous work, age was not found to be a good predictor of violations though driving experience was. Contrary to expectations, non-automotive (bicycle) roadway experience or level of driving training failed to predict poor driving behavior. On-road experience is the key to risk for China's drivers. Good agreement between the paper-based and Internet surveys indicate online surveys to be a feasible way to conduct research of driving behavior at low cost.

  3. Compendium of aberrant DNA methylation and histone modifications in cancer.

    PubMed

    Hattori, Naoko; Ushijima, Toshikazu

    2014-12-05

    Epigenetics now refers to the study or research field related to DNA methylation and histone modifications. Historically, global DNA hypomethylation was first revealed in 1983, and, after a decade, silencing of a tumor suppressor gene by regional DNA hypermethylation was reported. After the proposal of the histone code in the 2000s, alterations of histone methylation were also identified in cancers. Now, it is established that aberrant epigenetic alterations are involved in cancer development and progression, along with mutations and chromosomal losses. Recent cancer genome analyses have revealed a large number of mutations of epigenetic modifiers, supporting their important roles in cancer pathogenesis. Taking advantage of the reversibility of epigenetic alterations, drugs targeting epigenetic regulators and readers have been developed for restoration of normal pattern of the epigenome, and some have already demonstrated clinical benefits. In addition, DNA methylation of specific marker genes can be used as a biomarker for cancer diagnosis, including risk diagnosis, detection of cancers, and pathophysiological diagnosis. In this paper, we will summarize the major concepts of cancer epigenetics, placing emphasis on history.

  4. Mast cell desensitization inhibits calcium flux and aberrantly remodels actin

    PubMed Central

    Ang, W.X. Gladys; Church, Alison M.; Kulis, Mike; Choi, Hae Woong; Burks, A. Wesley

    2016-01-01

    Rush desensitization (DS) is a widely used and effective clinical strategy for the rapid inhibition of IgE-mediated anaphylactic responses. However, the cellular targets and underlying mechanisms behind this process remain unclear. Recent studies have implicated mast cells (MCs) as the primary target cells for DS. Here, we developed a murine model of passive anaphylaxis with demonstrated MC involvement and an in vitro assay to evaluate the effect of DS on MCs. In contrast with previous reports, we determined that functional IgE remains on the cell surface of desensitized MCs following DS. Despite notable reductions in MC degranulation following DS, the high-affinity IgE receptor FcεRI was still capable of transducing signals in desensitized MCs. Additionally, we found that displacement of the actin cytoskeleton and its continued association with FcεRI impede the capacity of desensitized MCs to evoke the calcium response that is essential for MC degranulation. Together, these findings suggest that reduced degranulation responses in desensitized MCs arise from aberrant actin remodeling, providing insights that may lead to improvement of DS treatments for anaphylactic responses. PMID:27669462

  5. Aberrant crypt foci in human colons: distribution and histomorphologic characteristics.

    PubMed

    Shpitz, B; Bomstein, Y; Mekori, Y; Cohen, R; Kaufman, Z; Neufeld, D; Galkin, M; Bernheim, J

    1998-05-01

    Aberrant crypt foci (ACF) are one of the earliest putative preneoplastic, and in some cases, neoplastic lesions in human colons. These microscopic lesions, identified on methylene blue-stained mucosa with a low-power-magnification microscope, are thought to be closely related to the earliest steps in multistage colonic tumorigenesis. We investigated the distribution pattern and histomorphological features of ACF in 74 patients with sporadic colorectal cancer. The distribution pattern shows a slightly higher prevalence with older age. The prevalence of the ACF in sigmoid colon was significantly higher in patients with colorectal cancer as compared with patients with benign colonic diseases. Also, significantly more ACF were detected in distal parts of the large bowel (descending, sigmoid colon, and rectum) than in proximal parts. Of 42 microdissected lesions, 12 were dysplastic and 30 were hyperplastic foci. The average size of dysplastic lesions was significantly larger than hyperplastic foci. More apoptotic bodies were found in dysplastic lesions. These lesions also showed an upward expansion of proliferative compartment and higher proliferation indices expressed as proliferating cell nuclear antigen-labeling index. Lymphoid follicles were frequently observed in the base of both hyperplastic and dysplastic foci (40% and 66.6%, respectively). The coincidence of lymphoid follicles was 2.5 to 8 times higher than expected. These features may be related to further progression of selected ACF during colorectal tumorigenesis.

  6. Aberrant Effective Connectivity in Schizophrenia Patients during Appetitive Conditioning

    PubMed Central

    Diaconescu, Andreea Oliviana; Jensen, Jimmy; Wang, Hongye; Willeit, Matthäus; Menon, Mahesh; Kapur, Shitij; McIntosh, Anthony R.

    2010-01-01

    It has recently been suggested that schizophrenia involves dysfunction in brain connectivity at a neural level, and a dysfunction in reward processing at a behavioral level. The purpose of the present study was to link these two levels of analyses by examining effective connectivity patterns between brain regions mediating reward learning in patients with schizophrenia and healthy, age-matched controls. To this aim, we used functional magnetic resonance imaging and galvanic skin recordings (GSR) while patients and controls performed an appetitive conditioning experiment with visual cues as the conditioned (CS) stimuli, and monetary reward as the appetitive unconditioned stimulus (US). Based on explicit stimulus contingency ratings, conditioning occurred in both groups; however, based on implicit, physiological GSR measures, patients failed to show differences between CS+ and CS− conditions. Healthy controls exhibited increased blood-oxygen-level dependent (BOLD) activity across striatal, hippocampal, and prefrontal regions and increased effective connectivity from the ventral striatum to the orbitofrontal cortex (OFC BA 11) in the CS+ compared to the CS− condition. Compared to controls, patients showed increased BOLD activity across a similar network of brain regions, and increased effective connectivity from the striatum to hippocampus and prefrontal regions in the CS− compared to the CS+ condition. The findings of increased BOLD activity and effective connectivity in response to the CS− in patients with schizophrenia offer insight into the aberrant assignment of motivational salience to non-reinforced stimuli during conditioning that is thought to accompany schizophrenia. PMID:21267430

  7. Chromosome aberrations induced by high-LET radiations

    NASA Technical Reports Server (NTRS)

    Kawata, Tetsuya; Ito, Hisao; George, Kerry; Wu, Honglu; Cucinotta, Francis A.

    2004-01-01

    Measurements of chromosome aberrations in peripheral blood lymphocytes are currently the most sensitive and reliable indicator of radiation exposure that can be used for biological dosimetry. This technique has been implemented recently to study radiation exposures incurred by astronauts during space flight, where a significant proportion of the dose is delivered by high-LET particle exposure. Traditional methods for the assessing of cytogenetic damage in mitotic cells collected at one time point after exposure may not be suitable for measuring high-LET radiation effects due to the drastic cell cycle perturbations and interphase cell death induced by this type of exposure. In this manuscript we review the recent advances in methodology used to study high-LET induced cytogenetic effects and evaluate the use of chemically-induced Premature Chromosome Condensation (PCC) as an alternative to metaphase analysis. Published data on the cytogenetic effects of in vitro exposures of high-LET radiation is reviewed, along with biodosimetry results from astronauts after short or long space missions.

  8. Factors associated with aberrant imprint methylation and oligozoospermia

    PubMed Central

    Kobayashi, Norio; Miyauchi, Naoko; Tatsuta, Nozomi; Kitamura, Akane; Okae, Hiroaki; Hiura, Hitoshi; Sato, Akiko; Utsunomiya, Takafumi; Yaegashi, Nobuo; Nakai, Kunihiko; Arima, Takahiro

    2017-01-01

    Disturbingly, the number of patients with oligozoospermia (low sperm count) has been gradually increasing in industrialized countries. Epigenetic alterations are believed to be involved in this condition. Recent studies have clarified that intrinsic and extrinsic factors can induce epigenetic transgenerational phenotypes through apparent reprogramming of the male germ line. Here we examined DNA methylation levels of 22 human imprinted loci in a total of 221 purified sperm samples from infertile couples and found methylation alterations in 24.8% of the patients. Structural equation model suggested that the cause of imprint methylation errors in sperm might have been environmental factors. More specifically, aberrant methylation and a particular lifestyle (current smoking, excess consumption of carbonated drinks) were associated with severe oligozoospermia, while aging probably affected this pathology indirectly through the accumulation of PCB in the patients. Next we examined the pregnancy outcomes for patients when the sperm had abnormal imprint methylation. The live-birth rate decreased and the miscarriage rate increased with the methylation errors. Our research will be useful for the prevention of methylation errors in sperm from infertile men, and sperm with normal imprint methylation might increase the safety of assisted reproduction technology (ART) by reducing methylation-induced diseases of children conceived via ART. PMID:28186187

  9. Criterion of phasing in the presence of segment aberrations

    NASA Astrophysics Data System (ADS)

    Wang, Shanshan; Zhu, Qiudong; Cao, Genrui; Wang, Xiao

    2008-03-01

    In order to achieve a spatial resolution comparable to a monolithic telescope of the same diameter, the segmented mirror surface must be phased with an accuracy about λ/20 wavefront rms, which is comparable with the accuracy of the segment figure. During the phasing procedure, piston, tip-tilt are controlled to achieve the best image quality of the telescope. The residual rms wavefront error of whole aperture taken as the merit function reaches minimum analytically when the least-square-fit plane of tested segment meets together with that of reference mirror, which means that "phasing" is a statistical mood of the whole aperture, not to match some small areas of the segments. The impact of segment aberration on the whole aperture residual rms wavefront error is simulated using the whole segment aperture sensing and edge sensing respectively. By the analytical and numerical simulation, it is demonstrated that the whole segment aperture phase sensing can make a better image quality than the edge sensing.

  10. Aberrant CpG Islands Hypermethylation Profiles in Malignant Gliomas

    PubMed Central

    Kim, Kwang Ryeol; Kim, Ealmaan

    2014-01-01

    Background The authors analyzed whether the promoter hypermethylation of cancer-related genes was involved in the tumorigenesis of malignant gliomas. Methods A total of 29 patients received surgery and histologically confirmed to have malignant gliomas from January 2000 to December 2006. The promoter methylation status of several genes, which were reported to be frequently methylated in malignant gliomas, was investigated using methylation-specific polymerase chain reaction. Results All cases of malignant gliomas represented the promoter hypermethylation in at least 2 or more genes tested. Of 29 tumors, 28 (96.55%) showed concurrent hypermethylation of 3 or more genes. Ras association domain family member 1, epithelial cadherin, O-6 methyl guanine DNA methyltransferase, thrombospondin 1, p14 and adenomatous polyposis coli were frequently methylated in high grade gliomas including glioblastomas, anaplastic astrocytomas, and anaplastic oligodendrogliomas. Conclusion Aberrant hypermethylation profile was closely related with malignant gliomas suggesting that epigenetic change may play a role in the development of malignant gliomas. Two or three target genes may provide useful clues to the development of the useful prognostic as well as diagnostic assays for malignant gliomas. PMID:24926469

  11. Aberrant Water Homeostasis Detected by Stable Isotope Analysis

    PubMed Central

    O'Grady, Shannon P.; Wende, Adam R.; Remien, Christopher H.; Valenzuela, Luciano O.; Enright, Lindsey E.; Chesson, Lesley A.; Abel, E. Dale; Cerling, Thure E.; Ehleringer, James R.

    2010-01-01

    While isotopes are frequently used as tracers in investigations of disease physiology (i.e., 14C labeled glucose), few studies have examined the impact that disease, and disease-related alterations in metabolism, may have on stable isotope ratios at natural abundance levels. The isotopic composition of body water is heavily influenced by water metabolism and dietary patterns and may provide a platform for disease detection. By utilizing a model of streptozotocin (STZ)-induced diabetes as an index case of aberrant water homeostasis, we demonstrate that untreated diabetes mellitus results in distinct combinations, or signatures, of the hydrogen (δ2H) and oxygen (δ18O) isotope ratios in body water. Additionally, we show that the δ2H and δ18O values of body water are correlated with increased water flux, suggesting altered blood osmolality, due to hyperglycemia, as the mechanism behind this correlation. Further, we present a mathematical model describing the impact of water flux on the isotopic composition of body water and compare model predicted values with actual values. These data highlight the importance of factors such as water flux and energy expenditure on predictive models of body water and additionally provide a framework for using naturally occurring stable isotope ratios to monitor diseases that impact water homeostasis. PMID:20657736

  12. Aberrant DNA methylation reprogramming in bovine SCNT preimplantation embryos

    PubMed Central

    Zhang, Sheng; Chen, Xin; Wang, Fang; An, Xinglan; Tang, Bo; Zhang, Xueming; Sun, Liguang; Li, Ziyi

    2016-01-01

    DNA methylation reprogramming plays important roles in mammalian embryogenesis. Mammalian somatic cell nuclear transfer (SCNT) embryos with reprogramming defects fail to develop. Thus, we compared DNA methylation reprogramming in preimplantation embryos from bovine SCNT and in vitro fertilization (IVF) and analyzed the influence of vitamin C (VC) on the reprogramming of DNA methylation. The results showed that global DNA methylation followed a typical pattern of demethylation and remethylation in IVF preimplantation embryos; however, the global genome remained hypermethylated in SCNT preimplantation embryos. Compared with the IVF group, locus DNA methylation reprogramming showed three patterns in the SCNT group. First, some pluripotency genes (POU5F1 and NANOG) and repeated elements (satellite I and α-satellite) showed insufficient demethylation and hypermethylation in the SCNT group. Second, a differentially methylated region (DMR) of an imprint control region (ICR) in H19 exhibited excessive demethylation and hypomethylation. Third, some pluripotency genes (CDX2 and SOX2) were hypomethylated in both the IVF and SCNT groups. Additionally, VC improved the DNA methylation reprogramming of satellite I, α-satellite and H19 but not that of POU5F1 and NANOG in SCNT preimplantation embryos. These results indicate that DNA methylation reprogramming was aberrant and that VC influenced DNA methylation reprogramming in SCNT embryos in a locus-specific manner. PMID:27456302

  13. Aberrant expression of RUNX3 in patients with immune thrombocytopenia.

    PubMed

    Qiao, Jianlin; Liu, Yun; Wu, Yulu; Li, Xiaoqian; Zhu, Feng; Xia, Yuan; Yao, Haina; Chu, Peipei; Li, Hongchun; Ma, Ping; Li, Depeng; Li, Zhenyu; Xu, Kailin; Zeng, Lingyu

    2015-09-01

    Immune thrombocytopenia (ITP) is an autoimmune disease, characterized by dysregulation of cellular immunity. Previous studies demonstrated that immune imbalance between Th1 and Th2 was associated with the pathogenesis of ITP. Runt-related transcription factor 3 (RUNX3) is a member of the runt domain-containing family of transcription factors and plays an important role in the regulation of T cell differentiation into Th1 cells. Whether RUNX3 was involved in the pathogenesis of ITP remains unclear. In this study, 47 active ITP patients, 18 ITP with remission and 26 age and gender matched healthy control were included. Peripheral blood mononuclear cells (PBMCs) were isolated from ITP and control for isolation of RNA and plasma which were used to measure mRNA level of RUNX3 and T-box transcription factor (T-bet) by quantitative real-time PCR and interferon γ (IFN-γ) plasma level by ELISA. Meanwhile, protein was also extracted from PBMCs for Western blot analysis of RUNX3 expression. Our results showed a significantly higher expression of RUNX3, T-bet and plasma level of IFN-γ in active ITP patients compared to control. No differences were observed between ITP with remission and control. Furthermore, a positive correlation of RUNX3 with T-bet was found in active ITP patients. In conclusion, aberrant expression of RUNX3 was associated with the pathogenesis of ITP and therapeutically targeting it might be a novel approach in ITP treatment.

  14. Aberration-free x-ray lenses made of silicon

    NASA Astrophysics Data System (ADS)

    Alianelli, L.; Pape, I.; Sutter, J. P.; Fox, O. J. L.; Sawhney, K. J. S.; Korwin-Mikke, K.

    2016-09-01

    Brilliant beams of hard x-rays, with geometrical cross-sections below 50×50 nm2, are a standard research tool for synchrotron users. With the advent of lower emittance sources, such as NSLSII, Petra III and Max IV, and planned upgraded lattices, such as APS-2, SPING8-II, ESRF II and DLS II, nanofocusing optics operating in transmission mode will become more competitive than they are currently. In general, they suffer from lower efficiency than reflective optics, however they often have easier set-up and alignment, combined with a smaller footprint. Fabrication and exploitation of ultra-short focal refractive lenses has not witnessed the same progress in the last decade as other optics, such as multilayer mirrors and multilayer Laue lenses. This paper reports on current status of high-resolution lithography for fabricating silicon lenses and on proposed designs for a new class of refractive lenses with zero aberrations and good efficiency. The new designs are created with geometrical parameters matching the spatial resolution achieved by modern lithography and silicon etch technology.

  15. Aberrant network connectivity during error processing in patients with schizophrenia

    PubMed Central

    Voegler, Rolf; Becker, Michael P.I.; Nitsch, Alexander; Miltner, Wolfgang H.R.; Straube, Thomas

    2016-01-01

    Background Neuroimaging methods have pointed to deficits in the interaction of large-scale brain networks in patients with schizophrenia. Abnormal connectivity of the right anterior insula (AI), a central hub of the salience network, is frequently reported and may underlie patients’ deficits in adaptive salience processing and cognitive control. While most previous studies used resting state approaches, we examined right AI interactions in a task-based fMRI study. Methods Patients with schizophrenia and healthy controls performed an adaptive version of the Eriksen Flanker task that was specifically designed to ensure a comparable number of errors between groups. Results We included 27 patients with schizophrenia and 27 healthy controls in our study. The between-groups comparison replicated the classic finding of reduced activation in the midcingulate cortex (MCC) in patients with schizophrenia during the commission of errors while controlling for confounding factors, such as task performance and error frequency, which have been neglected in many previous studies. Subsequent psychophysiological interaction analysis revealed aberrant functional connectivity (FC) between the right AI and regions in the inferior frontal gyrus and temporoparietal junction. Additionally, FC between the MCC and the dorsolateral prefrontal cortex was reduced. Limitations As we examined a sample of medicated patients, effects of antipsychotic medication may have influenced our results. Conclusion Overall, it appears that schizophrenia is associated with impairment of networks associated with detection of errors, refocusing of attention, superordinate guiding of cognitive control and their respective coordination. PMID:26836622

  16. Gender Differences in Risk Factors for Aberrant Prescription Opioid Use

    PubMed Central

    Jamison, Robert N.; Butler, Stephen F.; Budman, Simon H.; Edwards, Robert R.; Wasan, Ajay D.

    2009-01-01

    This is a longitudinal predictive study to examine gender differences in the clinical correlates of risk for opioid misuse among chronic pain patients prescribed opioids for pain. Two hundred seventy five male and 335 female patients prescribed opioids for chronic noncancer pain were asked to complete a series of baseline questionnaires, including the revised Screener and Opioid Assessment for Pain Patients (SOAPP-R). After five months the subjects were administered a structured prescription drug use interview (Prescription Drug Use Questionnaire; PDUQ), and submitted a urine sample for toxicology assessment. Their treating physicians also completed a substance misuse behavior checklist (Prescription Opioid Therapy Questionnaire; POTQ). At 5-month follow-up, women showed higher scores on the PDUQ (p<0.05), while men had a higher incidence of physician-rated aberrant drug behavior on the POTQ (p<0.05). An item analysis of the SOAPP-R, PDUQ and POTQ showed that women tended to score higher on items relating to psychological distress, while the male patients tended to report having more legal and behavioral problems. These results suggest that risk factors associated with prescription opioid misuse may differ between men and women. Perspective Understanding gender differences in substance abuse risk among chronic pain patients is important for clinical assessment and treatment. This study suggests that women are at greater risk to misuse opioids due to emotional issues and affective distress, while men tend to misuse opioids due to legal and problematic behavioral issues. PMID:19944648

  17. Unbiased Estimation of Refractive State of Aberrated Eyes

    PubMed Central

    Martin, Jesson; Vasudevan, Balamurali; Himebaugh, Nikole; Bradley, Arthur; Thibos, Larry

    2011-01-01

    To identify unbiased methods for estimating the target vergence required to maximize visual acuity based on wavefront aberration measurements. Experiments were designed to minimize the impact of confounding factors that have hampered previous research. Objective wavefront refractions and subjective acuity refractions were obtained for the same monochromatic wavelength. Accommodation and pupil fluctuations were eliminated by cycloplegia. Unbiased subjective refractions that maximize visual acuity for high contrast letters were performed with a computer controlled forced choice staircase procedure, using 0.125 diopter steps of defocus. All experiments were performed for two pupil diameters (3mm and 6mm). As reported in the literature, subjective refractive error does not change appreciably when the pupil dilates. For 3 mm pupils most metrics yielded objective refractions that were about 0.1D more hyperopic than subjective acuity refractions. When pupil diameter increased to 6 mm, this bias changed in the myopic direction and the variability between metrics also increased. These inaccuracies were small compared to the precision of the measurements, which implies that most metrics provided unbiased estimates of refractive state for medium and large pupils. A variety of image quality metrics may be used to determine ocular refractive state for monochromatic (635nm) light, thereby achieving accurate results without the need for empirical correction factors. PMID:21777601

  18. Profiles of aberrant white matter microstructure in fragile X syndrome

    PubMed Central

    Hall, Scott S.; Dougherty, Robert F.; Reiss, Allan L.

    2016-01-01

    Previous studies attempting to quantify white matter (WM) microstructure in individuals with fragile X syndrome (FXS) have produced inconsistent findings, most likely due to the various control groups employed, differing analysis methods, and failure to examine for potential motion artifact. In addition, analyses have heretofore lacked sufficient specificity to provide regional information. In this study, we used Automated Fiber-tract Quantification (AFQ) to identify specific regions of aberrant WM microstructure along WM tracts in patients with FXS that differed from controls who were matched on age, IQ and degree of autistic symptoms. Participants were 20 patients with FXS, aged 10 to 23 years, and 20 matched controls. Using Automated Fiber-tract Quantification (AFQ), we created Tract Profiles of fractional anisotropy and mean diffusivity along 18 major WM fascicles. We found that fractional anisotropy was significantly increased in the left and right inferior longitudinal fasciculus (ILF), right uncinate fasciculus, and left cingulum hippocampus in individuals with FXS compared to controls. Conversely, mean diffusivity was significantly decreased in the right ILF in patients with FXS compared to controls. Age was significantly negatively associated with MD values across both groups in 11 tracts. Taken together, these findings indicate that FXS results in abnormal WM microstructure in specific regions of the ILF and uncinate fasciculus, most likely caused by inefficient synaptic pruning as a result of decreased or absent Fragile X Mental Retardation Protein (FMRP). Longitudinal studies are needed to confirm these findings. PMID:26937381

  19. Perceived no reference image quality measurement for chromatic aberration

    NASA Astrophysics Data System (ADS)

    Lamb, Anupama B.; Khambete, Madhuri

    2016-03-01

    Today there is need for no reference (NR) objective perceived image quality measurement techniques as conducting subjective experiments and making reference image available is a very difficult task. Very few NR perceived image quality measurement algorithms are available for color distortions like chromatic aberration (CA), color quantization with dither, and color saturation. We proposed NR image quality assessment (NR-IQA) algorithms for images distorted with CA. CA is mostly observed in images taken with digital cameras, having higher sensor resolution with inexpensive lenses. We compared our metric performance with two state-of-the-art NR blur techniques, one full reference IQA technique and three general-purpose NR-IQA techniques, although they are not tailored for CA. We used a CA dataset in the TID-2013 color image database to evaluate performance. Proposed algorithms give comparable performance with state-of-the-art techniques in terms of performance parameters and outperform them in terms of monotonicity and computational complexity. We have also discovered that the proposed CA algorithm best predicts perceived image quality of images distorted with realistic CA.

  20. Adaptive Optics Analysis of Visual Benefit with Higher-order Aberrations Correction of Human Eye - Poster Paper

    NASA Astrophysics Data System (ADS)

    Xue, Lixia; Dai, Yun; Rao, Xuejun; Wang, Cheng; Hu, Yiyun; Liu, Qian; Jiang, Wenhan

    2008-01-01

    Higher-order aberrations correction can improve visual performance of human eye to some extent. To evaluate how much visual benefit can be obtained with higher-order aberrations correction we developed an adaptive optics vision simulator (AOVS). Dynamic real time optimized modal compensation was used to implement various customized higher-order ocular aberrations correction strategies. The experimental results indicate that higher-order aberrations correction can improve visual performance of human eye comparing with only lower-order aberration correction but the improvement degree and higher-order aberration correction strategy are different from each individual. Some subjects can acquire great visual benefit when higher-order aberrations were corrected but some subjects acquire little visual benefit even though all higher-order aberrations were corrected. Therefore, relative to general lower-order aberrations correction strategy, customized higher-order aberrations correction strategy is needed to obtain optimal visual improvement for each individual. AOVS provides an effective tool for higher-order ocular aberrations optometry for customized ocular aberrations correction.

  1. Diagnosis and treatment guidelines for aberrant portal hemodynamics: The Aberrant Portal Hemodynamics Study Group supported by the Ministry of Health, Labor and Welfare of Japan.

    PubMed

    2017-01-06

    Idiopathic portal hypertension (IPH), causing aberrant portal hemodynamics, is a disease with an as yet unidentified cause and no established treatment protocol. The Japanese research group on IPH in Japan was set up in 1975 by the Ministry of Health, Labor and Welfare. Extrahepatic portal obstruction and Budd-Chiari syndrome (BCS) have since been added to the group's research subjects. The aims of the research group are to accurately evaluate the current status of the three diseases in Japan, elucidate their etiology and pathogenesis, and develop new treatments. Due to the long-term efforts of the Japanese research group, aberrant portal hemodynamics has been investigated in a variety of aspects, from epidemiological and pathological studies to molecular biology analyses. As a result, it has been shown that there are abnormal genes in the liver, specific for IPH. In addition, pathological findings of BCS were internationally compared and the difference in findings between Japan and Europe (or North America) has been clarified. Furthermore, it was found that complication rates of hepatocellular carcinoma in BCS were higher in Japan. Based on the research, "Diagnosis and treatment of aberrant portal hemodynamics (2001)", including diagnostic criteria for aberrant portal hemodynamics, was published in 2001. In 2013, it was revised to "Diagnosis and treatment guidelines for aberrant portal hemodynamics (2013)" after the incorporation of diagnosis and treatment in accordance with its current status.

  2. Wave-front aberrations in the anterior corneal surface and the whole eye

    NASA Astrophysics Data System (ADS)

    He, Ji C.; Gwiazda, Jane; Thorn, Frank; Held, Richard

    2003-07-01

    In order to investigate the sources of wave-front aberrations in the human eye, we have measured the aberrations of the anterior cornea and the whole eye using a topographic system and a psychophysical wave-front sensor. We have also calculated the aberrations for the internal optics of both eyes of 45 young subjects (aged 9 to 29 years). The mean rms for the anterior cornea was similar to that for the internal optics and the whole eye when astigmatism was included, but less than that for both the internal optics and the whole eye with astigmatism removed. For eyes with low whole-eye rms values, mean rms for the anterior cornea was greater than that for the whole eye, suggesting that the anterior corneal aberration is partially compensated by the internal optics of the eye to produce the low whole-eye rms. For eyes with larger whole-eye rms values, the rms values for both the anterior cornea and the internal optics were less than that for the whole eye. Thus the aberrations for the two elements tend to be primarily additive. This pattern exists whether or not astigmatism was included in the wave-front aberration rms. For individual Zernike terms, astigmatism and spherical aberration in the anterior cornea were partially compensated by internal optics, while some other Zernike terms showed addition between the anterior cornea and internal optics. Individual eyes show different combinations of compensation and addition across different Zernike terms. Our data suggest that the reported loss of internal compensation for anterior corneal aberrations in elderly eyes with large whole-eye aberrations J. Opt. Soc. Am. A 19 , 137 (2002) may also occur in young eyes. 2003 Optical Society of America

  3. Aberration corrected STEM to study an ancient hair dyeing formula

    NASA Astrophysics Data System (ADS)

    Patriarche, G.; Van Elslande, E.; Castaing, J.; Walter, P.

    2014-05-01

    Lead-based chemistry was initiated in ancient Egypt for cosmetic preparation more than 4000 years ago. Here, we study a hair-dyeing recipe using lead salts described in text since Greco-Roman times. We report direct evidence about the shape and distribution of PbS nanocrystals that form within the hair during blackening.

  4. The shape of Eros

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.; Rosema, K. D.; Jurgens, R. F.

    1990-01-01

    Monte Carlo simulations are presently used to optimize estimation, ascertain associated errors, and guide bias-correction procedures, for the Eros polar silhouette convex hull that has been estimated from radar echo spectra. This hull is trapezoidal; this nonaxisymmetric shape may account for odd harmonics in Eros' echo spectral signature as a function of rotation phase. Additional constraints have been obtained for the figure of Eros through the inversion of the optical lightcurve to estimate the asteroid's two-dimensional average of the three-dimensional shape. This 'mean cross-section' and the polar silhouette exhibit similar elongations.

  5. [Aberrant internal carotid artery as a cause of pulsatile tinnitus: a difficult diagnosis in MRI?].

    PubMed

    Soyka, M B; Schuknecht, B; Huber, A M

    2010-02-01

    We present the case of a 43-year-old patient with sensorineural hearing loss and the finding of an aberrant internal carotid artery in the left tympanic cavity that was causing pulsatile tinnitus. The aberrant vessel was initially invisible on magnetic resonance imaging (MRI) and was confirmed by high-resolution computed tomography and MR angiography (MRA). Recognition of an aberrant course of an internal carotid artery often requires a combination of MRI and MRA to establish the diagnosis and rule out other differential diagnoses.

  6. Removing static aberrations from the active optics system of a wide-field telescope.

    PubMed

    Schipani, Pietro; Noethe, Lothar; Arcidiacono, Carmelo; Argomedo, Javier; Dall'Ora, Massimo; D'Orsi, Sergio; Farinato, Jacopo; Magrin, Demetrio; Marty, Laurent; Ragazzoni, Roberto; Umbriaco, Gabriele

    2012-07-01

    The wavefront sensor in active and adaptive telescopes is usually not in the optical path toward the scientific detector. It may generate additional wavefront aberrations, which have to be separated from the errors due to the telescope optics. The aberrations that are not rotationally symmetric can be disentangled from the telescope aberrations by a series of measurements taken in the center of the field, with the wavefront sensor at different orientation angles with respect to the focal plane. This method has been applied at the VLT Survey Telescope on the ESO Paranal observatory.

  7. Artificial neural network for the determination of Hubble Space Telescope aberration from stellar images

    NASA Technical Reports Server (NTRS)

    Barrett, Todd K.; Sandler, David G.

    1993-01-01

    An artificial-neural-network method, first developed for the measurement and control of atmospheric phase distortion, using stellar images, was used to estimate the optical aberration of the Hubble Space Telescope. A total of 26 estimates of distortion was obtained from 23 stellar images acquired at several secondary-mirror axial positions. The results were expressed as coefficients of eight orthogonal Zernike polynomials: focus through third-order spherical. For all modes other than spherical the measured aberration was small. The average spherical aberration of the estimates was -0.299 micron rms, which is in good agreement with predictions obtained when iterative phase-retrieval algorithms were used.

  8. Artificial neural network for the determination of Hubble Space Telescope aberration from stellar images.

    PubMed

    Barrett, T K; Sandler, D G

    1993-04-01

    An artificial-neural-network method, first developed for the measurement and control of atmospheric phase distortion, using stellar images, was used to estimate the optical aberration of the Hubble Space Telescope. A total of 26 estimates of distortion was obtained from 23 stellar images acquired at several secondary-mirror axial positions. The results were expressed as coefficients of eight orthogonal Zernike polynomials: focus through third-order spherical. For all modes other than spherical the measured aberration was small. The average spherical aberration of the estimates was -0.299 microm rms, which is in good agreement with predictions obtained when iterative phase-retrieval algorithms were used.

  9. Numerical parametric lens for shifting, magnification, and complete aberration compensation in digital holographic microscopy.

    PubMed

    Colomb, Tristan; Montfort, Frédéric; Kühn, Jonas; Aspert, Nicolas; Cuche, Etienne; Marian, Anca; Charrière, Florian; Bourquin, Sébastien; Marquet, Pierre; Depeursinge, Christian

    2006-12-01

    The concept of numerical parametric lenses (NPL) is introduced to achieve wavefront reconstruction in digital holography. It is shown that operations usually performed by optical components and described in ray geometrical optics, such as image shifting, magnification, and especially complete aberration compensation (phase aberrations and image distortion), can be mimicked by numerical computation of a NPL. Furthermore, we demonstrate that automatic one-dimensional or two-dimensional fitting procedures allow adjustment of the NPL parameters as expressed in terms of standard or Zernike polynomial coefficients. These coefficients can provide a quantitative evaluation of the aberrations generated by the specimen. Demonstration is given of the reconstruction of the topology of a microlens.

  10. Painting Analysis of Chromosome Aberrations Induced by Energetic Heavy Ions in Human Cells

    NASA Technical Reports Server (NTRS)

    Wu, Honglu

    2006-01-01

    FISH, mFISH, mBAND, telomere and centromere probes have been used to study chromosome aberrations induced in human cells exposed to low-and high-LET radiation in vitro. High-LET induced damages are mostly a single track effect. Unrejoined chromosome breaks (incomplete exchanges) and complex type aberrations were higher for high-LET. Biosignatures may depend on the method the samples are collected. Recent mBAND analysis has revealed more information about the nature of intra-chromosome exchanges. Whether space flight/microgravity affects radiation-induced chromosome aberration frequencies is still an open question.

  11. Recovering correct phase information in multiwavelength digital holographic microscopy by compensation for chromatic aberrations.

    PubMed

    De Nicola, S; Finizio, A; Pierattini, G; Alfieri, D; Grilli, S; Sansone, L; Ferraro, P

    2005-10-15

    We demonstrate experimentally that correct phase imaging without 2pi ambiguity is obtainable in digital holography by using a multiwavelength approach in the microscope configuration. We describe a general approach for removing chromatic aberrations and for controlling the pixel size of the reconstructed phase image in multiwavelength digital holography when the Fourier transform method is adopted for the numerical reconstruction of digital holograms. The retrieved phase is affected by the unavoidable, unwanted chromatic aberration. The correct phase can be obtained by evaluating the phase from the reference holograms reconstructed at different wavelengths to compensate for the chromatic aberration.

  12. CLASSICAL AREAS OF PHENOMENOLOGY: Study on the design and Zernike aberrations of a segmented mirror telescope

    NASA Astrophysics Data System (ADS)

    Jiang, Zhen-Yu; Li, Lin; Huang, Yi-Fan

    2009-07-01

    The segmented mirror telescope is widely used. The aberrations of segmented mirror systems are different from single mirror systems. This paper uses the Fourier optics theory to analyse the Zernike aberrations of segmented mirror systems. It concludes that the Zernike aberrations of segmented mirror systems obey the linearity theorem. The design of a segmented space telescope and segmented schemes are discussed, and its optical model is constructed. The computer simulation experiment is performed with this optical model to verify the suppositions. The experimental results confirm the correctness of the model.

  13. Aberration correction for transcranial photoacoustic tomography of primates employing adjunct image data

    PubMed Central

    Huang, Chao; Schoonover, Robert W.; Guo, Zijian; Schirra, Carsten O.; Anastasio, Mark A.; Wang, Lihong V.

    2012-01-01

    Abstract. A challenge in photoacoustic tomography (PAT) brain imaging is to compensate for aberrations in the measured photoacoustic data due to their propagation through the skull. By use of information regarding the skull morphology and composition obtained from adjunct x-ray computed tomography image data, we developed a subject-specific imaging model that accounts for such aberrations. A time-reversal-based reconstruction algorithm was employed with this model for image reconstruction. The image reconstruction methodology was evaluated in experimental studies involving phantoms and monkey heads. The results establish that our reconstruction methodology can effectively compensate for skull-induced acoustic aberrations and improve image fidelity in transcranial PAT. PMID:22734772

  14. Parallel direct laser writing in three dimensions with spatially dependent aberration correction.

    PubMed

    Jesacher, Alexander; Booth, Martin J

    2010-09-27

    We propose a hologram design process which aims at reducing aberrations in parallel three-dimensional direct laser writing applications. One principle of the approach is to minimise the diffractive power of holograms while retaining the degree of parallelisation. This reduces focal distortion caused by chromatic aberration. We address associated problems such as the zero diffraction order and aberrations induced by a potential refractive index mismatch between the immersion medium of the microscope objective and the fabrication substrate. Results from fabrication in diamond, fused silica and lithium niobate are presented.

  15. Aberration correction for transcranial photoacoustic tomography of primates employing adjunct image data

    NASA Astrophysics Data System (ADS)

    Huang, Chao; Nie, Liming; Schoonover, Robert W.; Guo, Zijian; Schirra, Carsten O.; Anastasio, Mark A.; Wang, Lihong V.

    2012-06-01

    A challenge in photoacoustic tomography (PAT) brain imaging is to compensate for aberrations in the measured photoacoustic data due to their propagation through the skull. By use of information regarding the skull morphology and composition obtained from adjunct x-ray computed tomography image data, we developed a subject-specific imaging model that accounts for such aberrations. A time-reversal-based reconstruction algorithm was employed with this model for image reconstruction. The image reconstruction methodology was evaluated in experimental studies involving phantoms and monkey heads. The results establish that our reconstruction methodology can effectively compensate for skull-induced acoustic aberrations and improve image fidelity in transcranial PAT.

  16. Characterization of misfit dislocations in Si quantum well structures enabled by STEM based aberration correction.

    PubMed

    Batson, Philip E; Lagos, Maureen J

    2017-03-02

    The success of aberration correction techniques at the end of the 20th century came at a time of increasing need for atomic resolution imaging to better understand known structural defects that influence semiconductor device operation, and to advance the search for new structures and behavior that will form the basis for devices in the future. With this in mind, it is a pleasure to recognize the contributions of Ondrej Krivanek to the success of aberration correction techniques, and his extension of aberration techniques to EELS equipment that further promises to unite structural studies with characterization of behavior from meV to keV energies in the STEM.

  17. Shape Aftereffects Reflect Shape Constancy Operations: Appearance Matters

    ERIC Educational Resources Information Center

    Storrs, Katherine R.; Arnold, Derek H.

    2013-01-01

    One of the oldest known visual aftereffects is the shape aftereffect, wherein looking at a particular shape can make subsequent shapes seem distorted in the opposite direction. After viewing a narrow ellipse, for example, a perfect circle can look like a broad ellipse. It is thought that shape aftereffects are determined by the dimensions of…

  18. Aberration-free and harmonic-free optics for time-resolved X-ray absorption spectroscopy using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Tolentino, H.; Baudelet, F.; Dartyge, E.; Fontaine, A.; Lena, A.; Tourillo, G.

    1990-04-01

    To obtain aberration-free optics, we tailored a new crystal shape which achieves an ellipsoidal profile. The theoretical shape has been designed using elastic equations and a ray-tracing technique. Cutting has been carried out and evaluation of the on-site performance has been achieved for a set of crystals. The size of the image turns out to be limited only by the demagnification factor and is restricted to about 300 μm. In order to get rid of the harmonic contamination and to get a reliable signal out of an absorbing sample we use a flat fused quartz mirror at grazing incidence as a low-pass filter. The performance of this filter has been studied experimentally by scanning the angle of the mirror relative to the beam and by a ray-tracing simulation. An adjustment of the grazing incident angle to reflect the fundamental without any harmonic contamination turns out to be an efficient and easy task in our current setup.

  19. The Shapes of Physics

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2013-01-01

    I have used many ploys to start a course in introductory physics, but one of the more interesting ones was to spend 20 minutes describing some of the curves and shapes that we would encounter in our year together. The students saw parabolas, catenaries, hyperbolas, cycloids, circles, ellipses, and helices, and were shown examples, either live or…

  20. Trends Shaping Education 2010

    ERIC Educational Resources Information Center

    OECD Publishing (NJ3), 2010

    2010-01-01

    "Trends Shaping Education 2010" brings together evidence showing the effects on education of globalisation, social challenges, changes in the workplace, the transformation of childhood, and ICT. To make the content accessible, each trend is presented on a double page, containing an introduction, two charts with brief descriptive text and a set of…

  1. Interactive shape metamorphosis

    NASA Technical Reports Server (NTRS)

    Chen, David T.; State, Andrei; Banks, David

    1994-01-01

    A technique for controlled metamorphosis between surfaces in 3-space is described. Well-understood techniques to produce shape metamorphosis between models in a 2D parametric space is applied. The user selects morphable features interactively, and the morphing process executes in real time on a high-performance graphics multicomputer.

  2. Nuclear shape isomers

    NASA Astrophysics Data System (ADS)

    Möller, P.; Sierk, A. J.; Bengtsson, R.; Sagawa, H.; Ichikawa, T.

    2012-03-01

    We calculate potential-energy surfaces as functions of spheroidal (ɛ2), hexadecapole (ɛ4), and axial-asymmetry (γ) shape coordinates for 7206 nuclei from A=31 to A=290. We tabulate the deformations and energies of all minima deeper than 0.2 MeV and of the saddles between all pairs of minima. The tabulation is terminated at N=160. Our study is based on the FRLDM macroscopic-microscopic model defined in ATOMIC DATA AND NUCLEAR DATA TABLES [P. Möller, J.R. Nix, W.D. Myers, W.J. Swiatecki, At. Data Nucl. Data Tables 59 (1995) 185]. We also present potential-energy contour plots versus ɛ2 and γ for 1224 even-even nuclei in the region studied. We can identify nuclei for which a necessary condition for shape isomers occurs, namely multiple minima in the calculated potential-energy surface. We find that the vast majority of nuclear shape isomers occur in the A=80 region, the A=100 region, and in a more extended region centered around 208Pb. A calculated region of shape isomers that has so far not been extensively explored is the region of neutron-deficient actinides "north-east" of 208Pb.

  3. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2002-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  4. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2000-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  5. How life shaped Earth.

    PubMed

    Gross, Michael

    2015-10-05

    Earth is much more complex than all the other solar system objects that we know. Thanks to its rich and diverse geology, our planet can offer habitats to a wide range of living species. Emerging insights suggest that this is not just a happy coincidence, but that life itself has in many ways helped to shape the planet.

  6. Shaping by Deposition

    DTIC Science & Technology

    1991-01-01

    pasticprototypegreater design flexibility , rapid fabrication, and reduce cost.odels are built directly fronm liquid photopolymers by Shaping deposition processes build...ate on design models to help the designer create manufactura - ble designs on the basis of requirements and limitations of the This paper describes the

  7. Tornado-Shaped Curves

    ERIC Educational Resources Information Center

    Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio

    2017-01-01

    In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.

  8. Sounds Exaggerate Visual Shape

    ERIC Educational Resources Information Center

    Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

  9. Orbital Shape Representations.

    ERIC Educational Resources Information Center

    Kikuchi, Osamu; Suzuki, Keizo

    1985-01-01

    Discusses the use of orbital shapes for instructional purposes, emphasizing that differences between polar, contour, and three-dimensional plots must be made clear to students or misconceptions will occur. Also presents three-dimensional contour surfaces for the seven 4f atomic orbitals of hydrogen and discusses their computer generation. (JN)

  10. Aberrant Behaviors and Road Accidents among Iranian Truck Drivers, 2010

    PubMed Central

    Ketabi, Damon; Barkhordari, Abalfazl; Mirmohammadi, Seyyed Jalil; Mehrparvar, Amir Houshang

    2011-01-01

    Background: Road accidents are a social phenomenon in different communities that its infra­structural dimensions of which as well as technologic failures such as road quality, and tech­nical faults of automobiles, need to be assessed in detail. Iran has the first order in the world for deadly road accidents. This study was designed to assess the association between aberrant behaviors of truck drivers and the incidence of road accidents in Yazd, center of Iran, in 2010. Methods: This cross-sectional descriptive-analytic study was conducted on 300 truck drivers in Yazd. We used 3 questionnaires, including one for demographic data, Driver Behavior Questionnaire (DBQ), and one for drivers' self-evaluation of the of their driving. Results: Five types of the behavior had the highest frequency: Misjudge speed of oncoming vehicle when overtaking.; Deliberately disregard the speed limits late at night or very early in the morning.; Ignore 'give way' signs, and narrowly avoid colliding with traffic having right of way.; Stuck behind a slow-moving vehicle on a two-lane highway, you are driven by frustration to try to overtake in risky circumstances.; Drive with only 'half-an-eye' on the road while looking at a map, changing a cassette or radio channel, etc. The more the driver's driv­ing was influenced by emotional and mental states the more deliberate violations and slips. Conclusion: Among truck drivers, safety has not developed sufficiently, and because of the dangers of road accidents both for the drivers and other people and its economic losses, the importance of the presenting some solutions is completely obvious. PMID:24688909

  11. Array CGH reveals genomic aberrations in human emphysema.

    PubMed

    Choi, Jin Soo; Lee, Woon Jeong; Baik, Seung Ho; Yoon, Hyoung Kyu; Lee, Kweon-Haeng; Kim, Yeul Hong; Lim, Young; Wang, Young-Pil

    2009-01-01

    Emphysema is the major component of chronic obstructive pulmonary disease (COPD), which is the fourth leading cause of death in the world. Several epidemiologic studies suggest that genetic factors may have an important role in the pathogenesis of emphysema. We analyzed the gene expression profiles of chromosomal aberrations using array comparative genomic hybridization (array CGH) in 32 patients with emphysema to identify the candidate genes that might be causally involved in the pathogenesis of emphysema. Copy number gains and losses were detected in chromosomal regions, and the corresponding genes were confirmed by real-time polymerase chain reaction. Several frequently altered loci were found, including a gain at 5p15.33 (60% of the study subjects), and a loss at 7q22.1 (31% of the study subjects). DNA gains were identified at a high frequency at 1p, 5p, 11p, 12p, 15q, 17p, 18q, 21q, and 22q, whereas DNA losses were frequently found at 7q and 22q. We found that the fold change levels were highest at the CYP4B1 (1p33), JUN (1p32.1), NOTCH2 (1p12-p11.2), SDHA (5p15.33), KCNQ1 (11p15.5-p15.4), NINJ2 (12p13.33), PCSK6 (15q26.3), ABR (17p13.3), CTDP1 (18q23), RUNX1 (21q22.12) and HDAC10 (22q13.33) gene loci. We also observed losses in the MUC17 (7q22.1), COMT (22q11.21) and GSTT1 (22q11.2) genes. These studies show that array CGH is a useful tool for the identification of gene alterations in cases of emphysema and that the aforementioned genes might represent potential candidate genes involved in the pathogenesis of emphysema.

  12. Aberrant miRNA profiles associated with chronic benzene poisoning.

    PubMed

    Bai, Wenlin; Chen, Yujiao; Yang, Jing; Niu, Piye; Tian, Lin; Gao, Ai

    2014-06-01

    Chronic occupational benzene exposure is associated with an increased risk of hematological malignancies. To gain an insight into the new biomarkers and molecular mechanisms of chronic benzene poisoning, miRNA profiles and mRNA expression pattern from the peripheral blood mononuclear cells of chronic benzene poisoning patients and health controls matched age and gender without benzene exposure were performed using the Exiqon miRNA PCR ARRAY and Gene Chip Human Gene 2.0ST Arrays, respectively. Totally, 6 up-regulated miRNAs (miR-34a, miR-205, miR-10b, let-7d, miR-185 and miR-423-5p-2) and 7 down-regulated miRNAs (miR-133a, miR-543, hsa-miR-130a, miR-27b,miR-223, miR-142-5p and miR-320b) were found in chronic benzene poisoning group compared to health controls (P ≤ 0.05). By integrating miRNA and mRNA expression data, these differential miRNAs were mainly involved in regulation of transcription from RNA polymerase II promoter, axon guidance, regulation of transcription, DNA-dependent, nervous system development, and regulation of actin cytoskeleton organization. Further, pathway analysis indicated that SMAD4, PLCB1, NFAT5, GNAI2, PTEN, VEGFA, BCL2, CTNNB1 and CCND1 were key target genes of differential miRNAs which were implicated in Adherens junction, TGF-beta signaling pathway, Wnt signaling pathway, tight junction and Pathways in cancer. In conclusion, the aberrant miRNAs might be a potential biomarker of chronic benzene poisoning.

  13. G2 chromatid aberrations: Kinetics and possible mechanisms

    SciTech Connect

    Bryant, P.E.; Slijepcevic, P. )

    1993-01-01

    Chromatid breaks and exchanges are induced by radiation in G2 mammalian cells. Breaks are at a maximum number at about 30 min after irradiation and decrease apparently exponentially with time between irradiation and sampling. Few breaks are observed immediately following exposure, probably as a result of selection of mitotic cells where chromosomes are condensed and there is consequently a lack of time for expression of damage. The change in frequency of breaks with time, from 30 min after radiation exposure and onwards, can be interpreted in two possible ways: either in terms of a repair process or in terms of a change in radiosensitivity through G2. However, the results with an inhibitor of repair of DNA double-strand breaks (ara A) and with [open quotes]transient hypothermia[close quotes] which extends the G2 phase, argue for an interpretation based on rejoining of chromatid breaks, possibly reflecting the repair of a subclass of dsb. Data from experiments with irradiated and restriction endonuclease treated radiosensitive mutant rodent lines indicate that enhanced levels of conversion of dsb into chromosomal aberrations may be largely independent of repair rates of bulk dsb. In CHO cells and in human lymphocytes exchanges initially increase rapidly with time and then remain at a constant frequency, supporting the notion of a uniform chromosomal radiosensitivity throughout most of G2 and providing further evidence that the mechanism for misjoining broken chromatids (leading to exchanges) is different from that for rejoining of chromatid breaks. Ratios of breaks to exchanges were found to vary in different cell lines and at different times during treatment with inhibitors or at altered temperatures, possibly (in different cell lines) indicating different levels of enzymes involved in misjoining, but suggesting that the mechanisms of chromosomal rejoining and misjoining are independent, at least to some degree. 19 refs., 11 figs., 1 tab.

  14. Aberrant Lymphatic Endothelial Progenitors in Lymphatic Malformation Development

    PubMed Central

    Wu, June K.; Kitajewski, Christopher; Reiley, Maia; Keung, Connie H.; Monteagudo, Julie; Andrews, John P.; Liou, Peter; Thirumoorthi, Arul; Wong, Alvin

    2015-01-01

    Lymphatic malformations (LMs) are vascular anomalies thought to arise from dysregulated lymphangiogenesis. These lesions impose a significant burden of disease on affected individuals. LM pathobiology is poorly understood, hindering the development of effective treatments. In the present studies, immunostaining of LM tissues revealed that endothelial cells lining aberrant lymphatic vessels and cells in the surrounding stroma expressed the stem cell marker, CD133, and the lymphatic endothelial protein, podoplanin. Isolated patient-derived CD133+ LM cells expressed stem cell genes (NANOG, Oct4), circulating endothelial cell precursor proteins (CD90, CD146, c-Kit, VEGFR-2), and lymphatic endothelial proteins (podoplanin, VEGFR-3). Consistent with a progenitor cell identity, CD133+ LM cells were multipotent and could be differentiated into fat, bone, smooth muscle, and lymphatic endothelial cells in vitro. CD133+ cells were compared to CD133− cells isolated from LM fluids. CD133− LM cells had lower expression of stem cell genes, but expressed circulating endothelial precursor proteins and high levels of lymphatic endothelial proteins, VE-cadherin, CD31, podoplanin, VEGFR-3 and Prox1. CD133− LM cells were not multipotent, consistent with a differentiated lymphatic endothelial cell phenotype. In a mouse xenograft model, CD133+ LM cells differentiated into lymphatic endothelial cells that formed irregularly dilated lymphatic channels, phenocopying human LMs. In vivo, CD133+ LM cells acquired expression of differentiated lymphatic endothelial cell proteins, podoplanin, LYVE1, Prox1, and VEGFR-3, comparable to expression found in LM patient tissues. Taken together, these data identify a novel LM progenitor cell population that differentiates to form the abnormal lymphatic structures characteristic of these lesions, recapitulating the human LM phenotype. This LM progenitor cell population may contribute to the clinically refractory behavior of LMs. PMID:25719418

  15. Angelman syndrome: A review highlighting musculoskeletal and anatomical aberrations.

    PubMed

    Sachdeva, Rohit; Donkers, Sarah J; Kim, Soo Y

    2016-07-01

    Angelman's syndrome (AS) is a genetic neurodevelopment disorder. The cause is a known abnormality involving the maternal inherited ubiquitin-protein ligase (UBE3A) gene. Clinical characteristics universal to the disorder are well documented in the literature and include developmental delay, seizures, ataxia, altered tone, severely impaired speech and intellect, as well as an overall happy demeanor, frequent bouts of laughter, and hypermotoric behavior. Associated with this disorder are several musculoskeletal aberrations. To date, a review of case studies reporting on these musculoskeletal changes has not been carried out. Thus, the purpose of this paper was to provide an overview of the musculoskeletal changes present in individuals with AS. In our review of 21 case reports from 1965-2013, the most consistently reported anatomical changes were of the craniofacial region. These include microcephaly, brachycephaly, a palpable occipital groove, prognathism, and wide spaced teeth. Other musculoskeletal abnormalities less frequently reported in the literature include scoliosis, excessive lumbar lordosis, and pes planus. Given that the majority of the case reports reviewed was of young children, the possibility of underreporting musculoskeletal changes which may manifest in the later years of life may be present. Early diagnosis and interventions to minimize secondary complications are crucial to maintain quality of life. An overall multidisciplinary approach is emphasized to maximize developmental potential for these individuals. Future prospective studies that follow patients into adulthood are needed to better understand the prevalence and development of secondary musculoskeletal changes, which in turn can inform intervention techniques and preventative measures. Clin. Anat. 29:561-567, 2016. © 2015 Wiley Periodicals, Inc.

  16. Aberrant crypt foci in patients with colorectal cancer.

    PubMed Central

    Roncucci, L.; Modica, S.; Pedroni, M.; Tamassia, M. G.; Ghidoni, M.; Losi, L.; Fante, R.; Di Gregorio, C.; Manenti, A.; Gafa, L.; Ponz de Leon, M.

    1998-01-01

    Aberrant crypt foci (ACF) are clusters of abnormally large colonic crypts identified on the mucosal surface of the human colon. They are thought to be preneoplastic lesions. The aim of the present study was to compare density (number of ACF per square cm of mucosal surface), crypt multiplicity (number of crypts per ACF) and histology of ACF in colonic resections of colorectal cancer patients resident in two Italian provinces with a twofold difference in colorectal cancer incidence rates. Thirty-two and 26 colonic resections were collected after operation in Ragusa (Southern Italy) and Modena (Northern Italy), respectively, and fixed in 10% formalin. Mucosal layers were observed under a light microscope at 25x after staining with methylene blue. Density of ACF was significantly higher in Modena (median 0.101 ACF cm(-2)) than in Ragusa (0.049, P = 0.001), whereas there was no difference in crypt multiplicity. ACF were classified into three groups according to histological features: ACF with mild alterations (hypertrophic ACF, 73%), ACF with hyperplasia (hyperplastic ACF, 17%) and ACF with dysplasia (microadenomas, 10%). The proportions of ACF in the three groups were similar in the two provinces. Density of ACF was higher and crypt multiplicity lower proceeding from proximal to distal large bowel. Microadenomas were observed only in the colon, whereas hyperplastic ACF were more frequent in the rectum. In conclusion, density of ACF correlates with colorectal cancer rates in two Italian provinces, and shows a positive gradient from proximal to distal large bowel. Histology of ACF suggests that they may be precursors of both hyperplastic and adenomatous polyps. These data provide further evidence of the role of ACF in human colorectal carcinogenesis. Images Figure 1 PMID:9649156

  17. Aberrant pulvinar effective connectivity in generalized social anxiety disorder

    PubMed Central

    Tadayonnejad, Reza; Klumpp, Heide; Ajilore, Olusola; Leow, Alex; Phan, Kinh Luan

    2016-01-01

    Abstract Recent neuroimaging findings in general social anxiety disorder (gSAD) have extended our understanding of the neural mechanisms of gSAD beyond an amygdala-centric fear-based hyperactivity model to include other brain regions and networks relevant to salient cues. In particular, higher order areas compromising visual networks that process emotional and social information have been implicated. The pulvinar anchors this network and is a key regulatory node that mediates complex sensory inputs and the integration between limbic and frontal brain systems. However, the role of the pulvinar and specifically alteration of its effective connectivity with the rest of the brain has not been examined in the pathophysiology of gSAD, a disorder characterized by aberrant socio-emotional processing. The main aim of this study was to examine the pulvinar network effective connectivity in gSAD. In this study, we recruited 21 individuals with gSAD and 19 demographically matched healthy controls (HC), who performed an emotional face processing task while brain activity was recorded using functional magnetic resonance imaging (fMRI). To examine pulvinar-based network dynamics, Granger causality (GC) based effective connectivity (EC) analysis was applied on fMRI data to compare gSAD and HC. The EC analysis revealed heightened casual influential dynamics between pulvinar in higher order visual and frontal regions in gSAD. In conclusion, these preliminary data suggest a novel network-based cortico-pulvino-cortical neural mechanism in the pathophysiology of gSAD. PMID:27828859

  18. The role of aberrant mitochondrial bioenergetics in diabetic neuropathy.

    PubMed

    Chowdhury, Subir K Roy; Smith, Darrell R; Fernyhough, Paul

    2013-03-01

    Diabetic neuropathy is a neurological complication of diabetes that causes significant morbidity and, because of the obesity-driven rise in incidence of type 2 diabetes, is becoming a major international health problem. Mitochondrial phenotype is abnormal in sensory neurons in diabetes and may contribute to the etiology of diabetic neuropathy where a distal dying-back neurodegenerative process is a key component contributing to fiber loss. This review summarizes the major features of mitochondrial dysfunction in neurons and Schwann cells in human diabetic patients and in experimental animal models (primarily exhibiting type 1 diabetes). This article attempts to relate these findings to the development of critical neuropathological hallmarks of the disease. Recent work reveals that hyperglycemia in diabetes triggers nutrient excess in neurons that, in turn, mediates a phenotypic change in mitochondrial biology through alteration of the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling axis. This vital energy sensing metabolic pathway modulates mitochondrial function, biogenesis and regeneration. The bioenergetic phenotype of mitochondria in diabetic neurons is aberrant due to deleterious alterations in expression and activity of respiratory chain components as a direct consequence of abnormal AMPK/PGC-1α signaling. Utilization of innovative respirometry equipment to analyze mitochondrial function of cultured adult sensory neurons from diabetic rodents shows that the outcome for cellular bioenergetics is a reduced adaptability to fluctuations in ATP demand. The diabetes-induced maladaptive process is hypothesized to result in exhaustion of the ATP supply in the distal nerve compartment and induction of nerve fiber dissolution. The role of mitochondrial dysfunction in the etiology of diabetic neuropathy is compared with other types of neuropathy with a distal dying-back pathology such as Friedreich

  19. Effects of ocular transverse chromatic aberration on peripheral word identification.

    PubMed

    Yang, Shun-Nan; Tai, Yu-chi; Laukkanen, Hannu; Sheedy, James E

    2011-11-01

    Transverse chromatic aberration (TCA) smears the retinal image of peripheral stimuli. We previously found that TCA significantly reduces the ability to recognize letters presented in the near fovea by degrading image quality and exacerbating crowding effect from adjacent letters. The present study examined whether TCA has a significant effect on near foveal and peripheral word identification, and whether within-word orthographic facilitation interacts with TCA effect to affect word identification. Subjects were briefly presented a 6- to 7-letter word of high or low frequency in each trial. Target words were generated with weak or strong horizontal color fringe to attenuate the TCA in the right periphery and exacerbate it in the left. The center of the target word was 1°, 2°, 4°, and 6° to the left or right of a fixation point. Subject's eye position was monitored with an eye-tracker to ensure proper fixation before target presentation. They were required to report the identity of the target word as soon and accurately as possible. Results show significant effect of color fringe on the latency and accuracy of word recognition, indicating existing TCA effect. Observed TCA effect was more salient in the right periphery, and was affected by word frequency more there. Individuals' subjective preference of color-fringed text was correlated to the TCA effect in the near periphery. Our results suggest that TCA significantly affects peripheral word identification, especially when it is located in the right periphery. Contextual facilitation such as word frequency interacts with TCA to influence the accuracy and latency of word recognition.

  20. The transglutaminase 2 gene is aberrantly hypermethylated in glioma

    PubMed Central

    Dyer, Lisa M.; Schooler, Kevin P.; Ai, Lingbao; Klop, Corinne; Qiu, Jingxin; Robertson, Keith D.

    2010-01-01

    Transglutaminase 2 (TG2) is a ubiquitously expressed protein that catalyzes protein/protein crosslinking. Because extracellular TG2 crosslinks components of the extracellular matrix, TG2 is thought to function as a suppressor of cellular invasion. We have recently uncovered that the TG2 gene (TGM2) is a target for epigenetic silencing in breast cancer, highlighting a molecular mechanism that drives reduced TG2 expression, and this aberrant molecular event may contribute to invasiveness in this tumor type. Because tumor invasiveness is a primary determinant of brain tumor aggressiveness, we sought to determine if TGM2 is targeted for epigenetic silencing in glioma. Analysis of TGM2 gene methylation in a panel of cultured human glioma cells indicated that the 5′ flanking region of the TGM2 gene is hypermethylated and that this feature is associated with reduced TG2 expression as judged by immunoblotting. Further, culturing glioma cells in the presence of the global DNA demethylating agent 5-aza-2′-deoxycytidine and the histone deacetylase inhibitor Trichostatin A resulted in re-expression of TG2 in these lines. In primary brain tumors we observed that the TGM2 promoter is commonly hypermethylated and that this feature is a cancer-associated phenomenon. Using publically available databases, TG2 expression in gliomas was found to vary widely, with many tumors showing overexpression or underexpression of this gene. Since overexpression of TG2 leads to resistance to doxorubicin through the ectopic activation of NFκB, we sought to examine the effects of recombinant TG2 expression in glioma cells treated with commonly used brain tumor therapeutics. We observed that in addition to doxorubicin, TG2 expression drove resistance to CCNU; however, TG2 expression did not alter sensitivity to other drugs tested. Finally, a catalytically null mutant of TG2 was also able to support doxorubicin resistance in glioma cells indicating that transglutaminase activity is not necessary

  1. Shape memory alloy thaw sensors

    DOEpatents

    Shahinpoor, Mohsen; Martinez, David R.

    1998-01-01

    A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the Austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states.

  2. Aberrations of varied line-space grazing incidence gratings in converging light beams

    NASA Technical Reports Server (NTRS)

    Hettrick, M. C.

    1984-01-01

    Analyses of the imaging properties of several designs for varied-line space gratings in converging beams of light in grazing-incidence spectrometers are presented. An explicit model is defined for the case of a plane-reflection grating intercepting light that converges and is reflected to a stigmatic point associated with the zero-order image of the grating. Smooth spatial variation of the grating constant then permits aberration correction. The aberrations are expressed as polynomials in the grating lens coordinates using power series expansions. Application of the model is illustrated in terms of aberrations experienced with the short wavelength spectrometer on the EUVE satellite. Attention is given to straight and parallel in-plane grooves, curved groove in-plane designs and off-plane grooves. Aberrations due to dispersions and misalignment are also considered.

  3. Manumycin A corrects aberrant splicing of Clcn1 in myotonic dystrophy type 1 (DM1) mice.

    PubMed

    Oana, Kosuke; Oma, Yoko; Suo, Satoshi; Takahashi, Masanori P; Nishino, Ichizo; Takeda, Shin'ichi; Ishiura, Shoichi

    2013-01-01

    Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults and as yet no cure for DM1. Here, we report the potential of manumycin A for a novel DM1 therapeutic reagent. DM1 is caused by expansion of CTG repeat. Mutant transcripts containing expanded CUG repeats lead to aberrant regulation of alternative splicing. Myotonia (delayed muscle relaxation) is the most commonly observed symptom in DM1 patients and is caused by aberrant splicing of the skeletal muscle chloride channel (CLCN1) gene. Identification of small-molecule compounds that correct aberrant splicing in DM1 is attracting much attention as a way of improving understanding of the mechanism of DM1 pathology and improving treatment of DM1 patients. In this study, we generated a reporter screening system and searched for small-molecule compounds. We found that manumycin A corrects aberrant splicing of Clcn1 in cell and mouse models of DM1.

  4. Method for reducing sidelobe impact of low order aberration in a coronagraph

    NASA Technical Reports Server (NTRS)

    Ftaclas, Christ (Inventor); Crout, Robert R. (Inventor)

    1995-01-01

    The invention relates to a method for reducing a sidelobe impact of low order aberrations using a coronagraph (2) having an apodized occulting mask (10), comprising the steps of: (a) providing in the coronagraph (2) the apodized occulting disk (10) having a transmission profile which graduates from opaque to transparent along its radius and the negative of whose amplitude transmission is a Gaussian profile; (b) determining a predicted sidelobe impact of the aberrations from a particular mix of low order aberration measured in a system as described by the Zernike polynomials; (c) applying the coronagraph to a system point spread function using a given rms width for the Gaussian profile describing the apodized occulting mask (10) and determining an attenuation level of the aberration sidelobes; (d) scaling the Gaussian occulting mask (10) profile to a wider rms width if the sidelobe attenuation level is too low; and (e) repeating the steps (b) through (d) until the attenuation level is acceptable.

  5. LS-CAP: an algorithm for identifying cytogenetic aberrations in hepatocellular carcinoma using microarray data.

    PubMed

    He, Xianmin; Wei, Qing; Sun, Meiqian; Fu, Xuping; Fan, Sichang; Li, Yao

    2006-05-01

    Biological techniques such as Array-Comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH) and affymetrix single nucleotide pleomorphism (SNP) array have been used to detect cytogenetic aberrations. However, on genomic scale, these techniques are labor intensive and time consuming. Comparative genomic microarray analysis (CGMA) has been used to identify cytogenetic changes in hepatocellular carcinoma (HCC) using gene expression microarray data. However, CGMA algorithm can not give precise localization of aberrations, fails to identify small cytogenetic changes, and exhibits false negatives and positives. Locally un-weighted smoothing cytogenetic aberrations prediction (LS-CAP) based on local smoothing and binomial distribution can be expected to address these problems. LS-CAP algorithm was built and used on HCC microarray profiles. Eighteen cytogenetic abnormalities were identified, among them 5 were reported previously, and 12 were proven by CGH studies. LS-CAP effectively reduced the false negatives and positives, and precisely located small fragments with cytogenetic aberrations.

  6. High-order aberration control during exposure for leading-edge lithography projection optics

    NASA Astrophysics Data System (ADS)

    Ohmura, Yasuhiro; Tsuge, Yosuke; Hirayama, Toru; Ikezawa, Hironori; Inoue, Daisuke; Kitamura, Yasuhiro; Koizumi, Yukio; Hasegawa, Keisuke; Ishiyama, Satoshi; Nakashima, Toshiharu; Kikuchi, Takahisa; Onda, Minoru; Takase, Yohei; Nagahiro, Akimasa; Isago, Susumu; Kawahara, Hidetaka

    2016-03-01

    High throughput with high resolution imaging has been key to the development of leading-edge microlithography. However, management of thermal aberrations due to lens heating during exposure has become critical for simultaneous achievement of high throughput and high resolution. Thermal aberrations cause CD drift and overlay error, and these errors lead directly to edge placement errors (EPE). Management and control of high order thermal aberrations is a critical requirement. In this paper, we will show practical performance of the lens heating with dipole and other typical illumination conditions for finer patterning. We confirm that our new control system can reduce the high-order aberrations and enable critical-dimension uniformity CDU during the exposure.

  7. Performance of Dispersed Fringe Sensor in the Presence of Segmented Mirror Aberrations: Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Shi, Fang; Basinger, Scott A.; Redding, David C.

    2006-01-01

    Dispersed Fringe Sensing (DFS) is an efficient and robust method for coarse phasing of a segmented primary mirror such as the James Webb Space Telescope (JWST). In this paper, modeling and simulations are used to study the effect of segmented mirror aberrations on the fringe image, DFS signals and DFS detection accuracy. The study has shown due to the pixilation spatial filter effect from DFS signal extraction the effect of wavefront error is reduced and DFS algorithm will be more robust against wavefront aberration by using multi-trace DFS approach. We also studied the JWST Dispersed Hartmann Sensor (DHS) performance in presence of wavefront aberrations caused by the gravity sag and we use the scaled gravity sag to explore the JWST DHS performance relationship with the level of the wavefront aberration. This also includes the effect from line-of-sight jitter.

  8. Aberrations in square pore micro-channel optics used for x-ray lobster eye telescopes

    NASA Astrophysics Data System (ADS)

    Willingale, R.; Pearson, J. F.; Martindale, A.; Feldman, C. H.; Fairbend, R.; Schyns, E.; Petit, S.; Osborne, J. P.; O'Brien, P. T.

    2016-07-01

    We identify all the significant aberrations that limit the performance of square pore micro-channel plate optics (MPOs) used as an X-ray lobster eye. These include aberrations intrinsic to the geometry, intrinsic errors associated with the slumping process used to introduce a spherical form to the plates and imperfections associated with the plate manufacturing process. The aberrations are incorporated into a comprehensive software model of the X-ray response of the optics and the predicted imaging response is compared with the measured X-ray performance obtained from a breadboard lobster eye. The results reveal the manufacturing tolerances which limit the current performance of MPOs and enable us to identify particular intrinsic aberrations which will limit the ultimate performance we can expect from MPO-lobster eye telescopes.

  9. Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

    PubMed

    Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

    2013-07-08

    The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

  10. Potential signal to accommodation from the Stiles–Crawford effect and ocular monochromatic aberrations

    PubMed Central

    Stark, Lawrence R.; Kruger, Philip B.; Rucker, Frances J.; Swanson, William H.; Schmidt, Nathan; Hardy, Caitlin; Rutman, Hadassa; Borgovan, Theodore; Burke, Sean; Badar, Mustanser; Shah, Raj

    2010-01-01

    The purpose of this study is to determine if cues within the blurred retinal image due to the Stiles–Crawford (SC) effect and the eye’s monochromatic aberrations can drive accommodation with a small pupil (3 mm) that is typical of bright photopic conditions. The foveal, psychophysical SC function (17 min arc) and ocular monochromatic aberrations were measured in 21 visually normal adults. The retinal image of a 10.2 min arc disc was simulated for spherical defocus levels of −1 D, 0 D and +1 D in each of four conditions consisting of combinations of the presence or absence of the individual SC function and monochromatic aberrations with a 3 mm pupil. Accommodation was recorded in eleven participants as each viewed the simulations through a 0.75-mm pinhole. The SC effect alone did not provide a significant cue to accommodation. Monochromatic aberrations provided a statistically significant but rather small cue to monocular accommodation. PMID:20835401

  11. Digital aberration correction of fluorescent images with coherent holographic image reconstruction by phase transfer (CHIRPT)

    NASA Astrophysics Data System (ADS)

    Field, Jeffrey J.; Bartels, Randy A.

    2016-03-01

    Coherent holographic image reconstruction by phase transfer (CHIRPT) is an imaging method that permits digital holographic propagation of fluorescent light. The image formation process in CHIRPT is based on illuminating the specimen with a precisely controlled spatio-temporally varying intensity pattern. This pattern is formed by focusing a spatially coherent illumination beam to a line focus on a spinning modulation mask, and image relaying the mask plane to the focal plane of an objective lens. Deviations from the designed spatio-temporal illumination pattern due to imperfect mounting of the circular modulation mask onto the rotation motor induce aberrations in the recovered image. Here we show that these aberrations can be measured and removed non-iteratively by measuring the disk aberration phase externally. We also demonstrate measurement and correction of systematic optical aberrations in the CHIRPT microscope.

  12. Aberration analysis of a concentric imaging spectrometer with a convex grating

    NASA Astrophysics Data System (ADS)

    Kim, Seo Hyun; Kong, Hong Jin; Chang, Soo

    2014-12-01

    We analyze the ray-optical aberrations in a concentric imaging spectrometer composed of one convex grating and two concave mirrors of different radii. We assume that the system is generally not telecentric. First we derive aberration functions of Seidel and Buchdahl types for a bundle of rays converging to dispersed Gaussian images. Next we discuss the conditions in which the third and fifth-order ray aberrations are balanced. Finally we show that a concentric imaging spectrometer for use with a CCD detector can be optimized effectively in the neighborhood of a stigmatic condition. The stigmatic condition derived here can be useful in rapidly creating an initial design of a concentric imaging spectrometer with minimal aberrations.

  13. Coma aberrations in combined two- and three-dimensional STED nanoscopy

    PubMed Central

    Antonello, Jacopo; Kromann, Emil B.; Burke, Daniel; Bewersdorf, Joerg; Booth, Martin J.

    2016-01-01

    Stimulated emission depletion (STED) microscopes, like all super-resolution methods, are sensitive to aberrations. Of particular importance are aberrations that affect the quality of the depletion focus, which requires a point of near-zero intensity surrounded by strong illumination. We present analysis, modeling, and experimental measurements that show the effects of coma aberrations on depletion patterns of two-dimensional (2D) and three-dimensional (3D) STED configurations. Specifically, we find that identical coma aberrations create focal shifts in opposite directions in 2D and 3D STED. This phenomenon could affect the precision of microscopic measurements and has ramifications for the efficacy of combined 2D/3D STED systems. PMID:27472636

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

    PubMed

    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.

  15. Investigation of aberration characteristics of eyes at a peripheral visual field by individual eye model.

    PubMed

    Lou, Qiqi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; Zhai, Yi; Fang, Hui

    2015-07-01

    We propose a method of constructing an individual eye model with a large visual field, and then investigate aberration characteristics of eyes in peripheral fields with constructed models. Twelve eyes of different aberrations are selected from 89 myopic eyes. It is shown that astigmatism increases as visual field in a quadratic manner. The variation tendency of defocus can be expressed by the cubic curve for 50% of eyes. For most of the eyes, the variation of spherical aberration shows a quadratic rule within ±24° visual field. Coma exhibits obvious individual differences. The impact of high-order aberrations on vision is mainly at a smaller visual field, and it becomes negligible beyond 24° visual field.

  16. Reverse chromatic aberration and its numerical optimization in a metamaterial lens.

    PubMed

    Capecchi, William J; Behdad, Nader; Volpe, Francesco A

    2012-04-09

    In planar metamaterial lenses, the focal point moves with the frequency. Here it is shown numerically that this movement can be controlled by properly engineering the dimensions of the metamaterial-based phase shifters that constitute the lens. In particular, such lenses can be designed to exhibit unusual chromatic aberration with the focal length increasing, rather than decreasing, with the frequency. It is proposed that such an artificial "reverse" chromatic aberration may optimize the transverse resolution of millimeter wave diagnostics of plasmas and be useful in compensating for the natural "ordinary" chromatic aberration of other components in an optical system. More generally, optimized chromatic aberration will allow for simultaneous focusing of several objects located at different distances and emitting or reflecting at different frequencies.

  17. Correction of chromatic aberrations at television registration of image through protective viewing systems

    NASA Astrophysics Data System (ADS)

    Kulyas, Oleg L.; Nikitin, Konstantin A.

    2016-03-01

    Ways of chromatic aberration in images are examined and analyzed which are generated at television supervision through protective glasses of a considerable thickness. The results of experimental check up of the given method of correction is introduced and described.

  18. Design of macro-filter-lens with simultaneous chromatic and geometric aberration correction.

    PubMed

    Prasad, Dilip K; Brown, Michael S

    2014-01-01

    A macro-filter-lens design that can correct for chromatic and geometric aberrations simultaneously while providing for a long focal length is presented. The filter is easy to fabricate since it involves two spherical surfaces and a planar surface. Chromatic aberration correction is achieved by making all the rays travel the same optical distance inside the filter element (negative meniscus). Geometric aberration is corrected for by the lens element (plano-convex), which makes the output rays parallel to the optic axis. This macro-filter-lens design does not need additional macro lenses and it provides an inexpensive and optically good (aberration compensated) solution for macro imaging of objects not placed close to the camera.

  19. Information transfer in a TEM corrected for spherical and chromatic aberration.

    PubMed

    Haider, M; Hartel, P; Müller, H; Uhlemann, S; Zach, J

    2010-08-01

    For the transmission electron aberration-corrected microscope (TEAM) initiative of five U.S. Department of Energy laboratories in the United States, a correction system for the simultaneous compensation of the primary axial aberrations, the spherical aberration Cs, and the chromatic aberration Cc has been developed and successfully installed. The performance of the resulting Cc /Cs-corrected TEAM instrument has been investigated thoroughly. A significant improvement of the linear contrast transfer can be demonstrated. The information about the instrument one obtains using Young's fringe method is compared for uncorrected, Cs-corrected, and Cc /Cs-corrected instruments. The experimental results agree well with simulations. The conclusions might be useful to others in understanding the process of image formation in a Cc /Cs-corrected transmission electron microscope.

  20. Analysis of chromosomal aberrations and recombination by allelic bias in RNA-Seq

    PubMed Central

    Weissbein, Uri; Schachter, Maya; Egli, Dieter; Benvenisty, Nissim

    2016-01-01

    Genomic instability has profound effects on cellular phenotypes. Studies have shown that pluripotent cells with abnormal karyotypes may grow faster, differentiate less and become more resistance to apoptosis. Previously, we showed that microarray gene expression profiles can be utilized for the analysis of chromosomal aberrations by comparing gene expression levels between normal and aneuploid samples. Here we adopted this method for RNA-Seq data and present eSNP-Karyotyping for the detection of chromosomal aberrations, based on measuring the ratio of expression between the two alleles. We demonstrate its ability to detect chromosomal gains and losses in pluripotent cells and their derivatives, as well as meiotic recombination patterns. This method is advantageous since it does not require matched diploid samples for comparison, is less sensitive to global expression changes caused by the aberration and utilizes already available gene expression profiles to determine chromosomal aberrations. PMID:27385103

  1. Multiple sextupole system for the correction of third and higher order aberration

    DOEpatents

    Crewe, Albert V.

    1983-01-01

    A means is provided for compensating for third and higher order aberration in charged particle beam devices. The means includes two sextupoles with an intermediate focusing lens, all positioned between two focusing lenses.

  2. MORPHEUS' MOLECULE1 is required to prevent aberrant RNA transcriptional read-through in Arabidopsis.

    PubMed

    Zhou, Yue; Zhang, Jun; Lin, Huixin; Guo, Guangqin; Guo, Yan

    2010-11-01

    Several pathways function to remove aberrant mRNA in eukaryotic cells; however, the exact mechanisms underlying the restriction of aberrant mRNA transcription are poorly understood. In this study, we found that MORPHEUS' MOLECULE1 (MOM1) is a key component of this regulatory machinery. The Arabidopsis (Arabidopsis thaliana) mom1-44 mutation was identified by luciferase imaging in transgenic plants harboring a cauliflower mosaic virus 35S promoter-LUCIFERASE transgene lacking the 3'-untranslated region. In the mom1-44 mutant, transcriptional read-though occurred in genes with an aberrant RNA structure. Analysis of an RNA-dependent RNA polymerase2 mom1 double mutant revealed that the RNA-directed DNA methylation pathway is not involved in this regulatory process. Moreover, the prevention of aberrant mRNA transcriptional read-through by MOM1 is gene locus and transgene copy number independent.

  3. Right aortic arch with aberrant left innominate artery arising from Kommerell's diverticulum*

    PubMed Central

    Faistauer, Ângela; Torres, Felipe Soares; Faccin, Carlo Sasso

    2016-01-01

    We report a case of an uncommon thoracic aorta anomaly-right aortic arch with aberrant left innominate artery arising from Kommerell's diverticulum-that went undiagnosed until adulthood. PMID:27777481

  4. Orthonormal aberration polynomials for anamorphic optical imaging systems with circular pupils.

    PubMed

    Mahajan, Virendra N

    2012-06-20

    In a recent paper, we considered the classical aberrations of an anamorphic optical imaging system with a rectangular pupil, representing the terms of a power series expansion of its aberration function. These aberrations are inherently separable in the Cartesian coordinates (x,y) of a point on the pupil. Accordingly, there is x-defocus and x-coma, y-defocus and y-coma, and so on. We showed that the aberration polynomials orthonormal over the pupil and representing balanced aberrations for such a system are represented by the products of two Legendre polynomials, one for each of the two Cartesian coordinates of the pupil point; for example, L(l)(x)L(m)(y), where l and m are positive integers (including zero) and L(l)(x), for example, represents an orthonormal Legendre polynomial of degree l in x. The compound two-dimensional (2D) Legendre polynomials, like the classical aberrations, are thus also inherently separable in the Cartesian coordinates of the pupil point. Moreover, for every orthonormal polynomial L(l)(x)L(m)(y), there is a corresponding orthonormal polynomial L(l)(y)L(m)(x) obtained by interchanging x and y. These polynomials are different from the corresponding orthogonal polynomials for a system with rotational symmetry but a rectangular pupil. In this paper, we show that the orthonormal aberration polynomials for an anamorphic system with a circular pupil, obtained by the Gram-Schmidt orthogonalization of the 2D Legendre polynomials, are not separable in the two coordinates. Moreover, for a given polynomial in x and y, there is no corresponding polynomial obtained by interchanging x and y. For example, there are polynomials representing x-defocus, balanced x-coma, and balanced x-spherical aberration, but no corresponding y-aberration polynomials. The missing y-aberration terms are contained in other polynomials. We emphasize that the Zernike circle polynomials, although orthogonal over a circular pupil, are not suitable for an anamorphic system as

  5. Temporal Dependence of Chromosomal Aberration on Radiation Quality and Cellular Genetic Background

    NASA Technical Reports Server (NTRS)

    Lu, Tao; Zhang, Ye; Krieger, Stephanie; Yeshitla, Samrawit; Goss, Rosalin; Bowler, Deborah; Kadhim, Munira; Wilson, Bobby; Wu, Honglu

    2017-01-01

    Radiation induced cancer risks are driven by genetic instability. It is not well understood how different radiation sources induce genetic instability in cells with different genetic background. Here we report our studies on genetic instability, particularly chromosome instability using fluorescence in situ hybridization (FISH), in human primary lymphocytes, normal human fibroblasts, and transformed human mammary epithelial cells in a temporal manner after exposure to high energy protons and Fe ions. The chromosome spread was prepared 48 hours, 1 week, 2 week, and 1 month after radiation exposure. Chromosome aberrations were analyzed with whole chromosome specific probes (chr. 3 and chr. 6). After exposure to protons and Fe ions of similar cumulative energy (??), Fe ions induced more chromosomal aberrations at early time point (48 hours) in all three types of cells. Over time (after 1 month), more chromosome aberrations were observed in cells exposed to Fe ions than in the same type of cells exposed to protons. While the mammary epithelial cells have higher intrinsic genetic instability and higher rate of initial chromosome aberrations than the fibroblasts, the fibroblasts retained more chromosomal aberration after long term cell culture (1 month) in comparison to their initial frequency of chromosome aberration. In lymphocytes, the chromosome aberration frequency at 1 month after exposure to Fe ions was close to unexposed background, and the chromosome aberration frequency at 1 month after exposure to proton was much higher. In addition to human cells, mouse bone marrow cells isolated from strains CBA/CaH and C57BL/6 were irradiated with proton or Fe ions and were analyzed for chromosome aberration at different time points. Cells from CBA mice showed similar frequency of chromosome aberration at early and late time points, while cells from C57 mice showed very different chromosome aberration rate at early and late time points. Our results suggest that relative

  6. Design of eye models used in quantitative analysis of interaction between chromatic and higher-order aberrations of eye

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Special kinds of eye models are constructed by means of optical system design to quantitatively investigate impacts of longitudinal chromatic aberration (LCA), transverse chromatic aberration (TCA) and LCA+TCA on retina image quality and on depth of focus (DOF), as well as interaction between chromatic and higher-order aberrations. Results show that LCA plays a main role in enhancement of DOF and higher-order aberrations further increase DOF. For most of the eyes the impact of higher-order aberrations on vision is much smaller than that of LCA+TCA and the presence of LCA+TCA further reduces the impact of higher-order aberrations. The impact of LCA approximates to that of LCA+TCA, and the impact of TCA approximates to that of normal level of higher-order aberrations and is negligible.

  7. Improving the quality perception of digital images using modified method of the eye aberration correction

    NASA Astrophysics Data System (ADS)

    Kvyetnyy, Roman; Sofina, Olga; Orlyk, Pavel; Utreras, Andres J.; Smolarz, Andrzej; Wójcik, Waldemar; Orazalieva, Sandugash

    2016-09-01

    A new approach to solve the problem of image correction to improve the quality perception of graphic information by people with aberrations of the eye optical system is considered in given article. The model of higher order aberrations which may appear in the human eye optical system is described. The developed approach is based on the pre-processing of digital images and applying of the filtration methods to the adjusted images.

  8. Increased risk of cancer in radon-exposed miners with elevated frequency of chromosomal aberrations.

    PubMed

    Smerhovsky, Zdenek; Landa, Karel; Rössner, Pavel; Juzova, Dagmar; Brabec, Marek; Zudova, Zdena; Hola, Nora; Zarska, Hana; Nevsimalova, Emilie

    2002-02-15

    In spite of the extensive use of cytogenetic analysis of human peripheral blood lymphocytes in the biomonitoring of exposure to various mutagens and carcinogens, the long-term effects of an increased frequency of chromosomal aberrations in individuals are still uncertain. Few epidemiologic studies have addressed this issue, and a moderate risk of cancer in individuals with an elevated frequency of chromosomal aberrations has been observed. In the present study, we analyzed data on 1323 cytogenetic assays and 225 subjects examined because of occupational exposures to radon (range of exposure from 1.7 to 662.3 working level month (WLM)). Seventy-five subjects were non-smokers. We found 36 cases of cancer in this cohort. Chromatid breaks were the most frequently observed type of aberrations (mean frequency 1.2 per 100 cells), which statistically significantly correlated with radon exposure (Spearman's correlation coefficient R=0.22, P<0.001). Also, the frequency of aberrant cells (median of 2.5%) correlated with radon exposure (Spearman's correlation coefficient R=0.16, P<0.02). Smoking and silicosis were not associated with results of cytogenetic analyses. The Cox regression models, which accounted for the age at time of first cytogenetic assay, radon exposure, and smoking showed strong and statistically significant associations between cancer incidence and frequency of chromatid breaks and frequency of aberrant cells, respectively. A 1% increase in the frequency of aberrant cells was paralleled by a 62% increase in risk of cancer (P<0.000). An increase in frequency of chromatid breaks by 1 per 100 cells was followed by a 99% increase in risk of cancer (P<0.000). We obtained similar results when we analyzed the incidence of lung cancer and the incidence other than lung cancer separately. Contrary to frequency of chromatid breaks and frequency of aberrant cells, the frequency of chromatid exchanges, and chromosome-type aberrations were not predictive of cancer.

  9. Investigation of an Aberrant Cell Voltage During the Filling of a Large Lithium Thionyl Chloride Cell

    NASA Technical Reports Server (NTRS)

    Thaller, Lawrence H.; Quinzio, Michael V.

    1997-01-01

    The investigation of an aberrant cell voltage during the filling of a large lithium thionyl chloride cell summary is at: an aberrant voltage trace was noted during the review of cell filling data; incident was traced to an interruption during filling; experimentation suggested oxidizable sites within the carbon electrode were responsible for the drop in voltage; the voltage anomaly could be reproduced by interrupting the filling of similar cells; and anomalous voltage dip was not due to a short.

  10. Intrinsic factors that can affect sensitivity to chromosome-aberration induction

    SciTech Connect

    Preston, R.J.

    1982-01-01

    The paper addresses the question, are there individuals who are hypersensitive, or are more likely to be hypersensitive, to the induction of chromosome aberrations by radiation and chemicals. Lymphocytes of persons heterozygous for xeroderma pigmentosum, ataxia telangiectasia, and Fauconi's anemia were subjected to chemical and/or ionizing radiations to determine their sensitivity to chromosome aberration induction. In the majority of cases the sensitivity was intermediate between that of normal individuals and homozygotes for these genes. (ACR)

  11. Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation.

    PubMed

    Carrascal, Carolina Amador; Aristizabal, Sara; Greenleaf, James F; Urban, Matthew W

    2016-02-01

    Elasticity is measured by shear wave elasticity imaging (SWEI) methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study, the effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency, and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using fast object-oriented C++ ultrasound simulator (FOCUS) and shear wave simulations using finite-element-model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results: The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40%-90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, and the resulting Pearson's correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (phase aberration and attenuation case), measured phase screen, (only phase aberration case), and FOCUS/FEM model (only attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation.

  12. Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation

    PubMed Central

    Amador, Carolina; Aristizabal, Sara; Greenleaf, James F.; Urban, Matthew W.

    2016-01-01

    Tissue elasticity is measured by shear wave elasticity imaging methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using FOCUS and shear wave simulations using Finite Element Model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40% to 90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, the resulting Pearson’s correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (Phase Aberration and Attenuation case), measured phase screen (Only Phase Aberration case) and FOCUS/FEM model (Only Attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation. PMID:26742131

  13. Robust, optimal subsonic airfoil shapes

    NASA Technical Reports Server (NTRS)

    Rai, Man Mohan (Inventor)

    2008-01-01

    Method system, and product from application of the method, for design of a subsonic airfoil shape, beginning with an arbitrary initial airfoil shape and incorporating one or more constraints on the airfoil geometric parameters and flow characteristics. The resulting design is robust against variations in airfoil dimensions and local airfoil shape introduced in the airfoil manufacturing process. A perturbation procedure provides a class of airfoil shapes, beginning with an initial airfoil shape.

  14. Stable and Unstable Chromosome Aberrations Measured after Occupational Exposure to Ionizing Radiation and Ultrasound

    PubMed Central

    Fučić, Aleksandra; Želježić, Davor; Kašuba, Vilena; Kopjar, Nevenka; Rozgaj, Ružica; Lasan, Ružica; Mijić, August; Hitrec, Vlasta; Lucas, Joe Nathan

    2007-01-01

    Aim To evaluate chromosome aberration and fluorescent in situ hybridization (FISH) assays as a method to estimate of health risk, we monitored 9 male subjects occupationally exposed to low doses of both ionizing radiation and ultrasound during a period of over 3 years. Methods Sampling was performed at 6-month intervals during a three-year period. First we used conventional chromosomal aberrations analysis. When the aberration frequency for a particular subject reached the background, we measured translocations in the final sample, using fluorescence in situ hybridization. Chromosome painting probes for chromosomes 1, 2, and 4 were used simultaneously. Results Dicentric and ring chromosomes were eliminated within a year. Translocations persisted and deviated from control values in all examinees. Translocations were detected long after unstable aberrations decreased to the background level. Conclusion Fluorescence in situ hybridization-based translocation detection was a reliable method for monitoring chronic occupational clastogen exposure. Chromosome aberration assay correlated with translocation frequency. Stable chromosomal aberrations reflected cumulative genome damage during job exposure. PMID:17589981

  15. Characterisation of the effects of optical aberrations in single molecule techniques

    PubMed Central

    Coles, Benjamin C.; Webb, Stephen E. D.; Schwartz, Noah; Rolfe, Daniel J.; Martin-Fernandez, Marisa; Lo Schiavo, Valentina

    2016-01-01

    Optical aberrations degrade image quality in fluorescence microscopy, including for single-molecule based techniques. These depend on post-processing to localize individual molecules in an image series. Using simulated data, we show the impact of optical aberrations on localization success, accuracy and precision. The peak intensity and the proportion of successful localizations strongly reduces when the aberration strength is greater than 1.0 rad RMS, while the precision of each of those localisations is halved. The number of false-positive localisations exceeded 10% of the number of true-positive localisations at an aberration strength of only ~0.6 rad RMS when using the ThunderSTORM package, but at greater than 1.0 rad RMS with the Radial Symmetry package. In the presence of coma, the localization error reaches 100 nm at ~0.6 rad RMS of aberration strength. The impact of noise and of astigmatism for axial resolution are also considered. Understanding the effect of aberrations is crucial when deciding whether the addition of adaptive optics to a single-molecule microscope could significantly increase the information obtainable from an image series. PMID:27231619

  16. Characterisation of the effects of optical aberrations in single molecule techniques.

    PubMed

    Coles, Benjamin C; Webb, Stephen E D; Schwartz, Noah; Rolfe, Daniel J; Martin-Fernandez, Marisa; Lo Schiavo, Valentina

    2016-05-01

    Optical aberrations degrade image quality in fluorescence microscopy, including for single-molecule based techniques. These depend on post-processing to localize individual molecules in an image series. Using simulated data, we show the impact of optical aberrations on localization success, accuracy and precision. The peak intensity and the proportion of successful localizations strongly reduces when the aberration strength is greater than 1.0 rad RMS, while the precision of each of those localisations is halved. The number of false-positive localisations exceeded 10% of the number of true-positive localisations at an aberration strength of only ~0.6 rad RMS when using the ThunderSTORM package, but at greater than 1.0 rad RMS with the Radial Symmetry package. In the presence of coma, the localization error reaches 100 nm at ~0.6 rad RMS of aberration strength. The impact of noise and of astigmatism for axial resolution are also considered. Understanding the effect of aberrations is crucial when deciding whether the addition of adaptive optics to a single-molecule microscope could significantly increase the information obtainable from an image series.

  17. Effects of long-term radiation exposure on chromosomal aberrations in radiological technologists.

    PubMed

    Kumagai, E; Tanaka, R; Kumagai, T; Onomichi, M; Sawada, S

    1990-09-01

    Chromosomal aberrations in the lymphocytes of radiation technologists (RT) were analyzed by the trypsin G-banding method to study the late effects of long-term exposure to low doses of radiation. Structural aberrations were identified in 384 (2.5%) of 15,442 cells analyzed from 53 RT as compared to 177 (1.6%) of 11,136 cells from 36 healthy controls. Stable aberrations were the most frequent in both groups and were either translocations or deletions. Unstable aberrations were mainly acentric fragments in both groups. The frequency of translocations and acentric fragments was significantly higher in the RT than in the controls and was highest in the RT over 50 years. The highest frequency observed in the greater than 50 age group was attributed to the unknown for cumulative dose prior to introduction of film badges. Frequency of chromosomal aberrations correlated with the estimated dose from the film badges and years of experience of each RT based on the equation y = 0.22 + 0.37D + 4.35D2, where y is overall frequency of chromosomal aberrations and D is the estimated radiation dose in Sv.

  18. The effect of ocular aberrations on steady-state errors of accommodative response.

    PubMed

    Plainis, Sotiris; Ginis, Harilaos S; Pallikaris, Aristophanis

    2005-05-23

    It is well accepted that the accommodation system is characterized by steady-state errors in focus. The purpose of this study was to correlate these errors with changes in ocular wavefront aberration and corresponding image quality when accommodating. A wavefront analyzing system, the Complete Ophthalmic Analysis System (COAS), was used in conjunction with a Badal optometer to allow continuous recording of the aberration structure of the eye for a range of accommodative demands (up to 8 D). Fifty consecutive recordings from seven subjects were taken. Monocular accommodative response was calculated as (i) the equivalent refraction minimizing wavefront error and (ii) the defocus needed to optimize the modulation transfer function at high spatial frequencies. Previously reported changes in ocular aberrations with accommodation (e.g., the shift of spherical aberration to negative values) were confirmed. Increased accommodation errors for near targets (lags) were evident for all subjects, although their magnitude showed a significant intersubject variability. It is concluded that the one-to-one stimulus/response slope in accommodation function should not always be considered as ideal, because higher order aberrations, especially changes of spherical aberration, may influence the actual accommodative demand. Fluctuations may serve to preserve image quality when errors of accommodation are moderate, by temporarily searching for the best focus.

  19. Effects of Valproic Acid on Radiation-Induced Chromosomal Aberrations in Human Lymphocytes

    PubMed Central

    Di Tomaso, María Vittoria; Gregoire, Eric; Martínez-López, Wilner

    2017-01-01

    One of the most widely employed histone deacetylases inhibitors in the clinic is the valproic acid (VA), proving to have a good tolerance and low side effects on human health. VA induces changes in chromatin structure making DNA more susceptible to damage induction and influence DNA repair efficiency. VA is also proposed as a radiosensitizing agent. To know if VA is suitable to sensitize human lymphocytes γ-irradiation in vitro, different types of chromosomal aberrations in the lymphocytes, either in the absence or presence of VA, were analyzed. For this purpose, blood samples from four healthy donors were exposed to γ-rays at a dose of 1.5 Gy and then treated with two different doses of VA (0.35 or 0.70 mM). Unstable and stable chromosomal aberrations were analyzed by means of fluorescence in situ hybridization. Human lymphocytes treated with VA alone did not show any increase in the frequency of chromosomal aberrations. However, a moderate degree of sensitization was observed, through the increase of chromosomal aberrations, when 0.35 mM VA was employed after γ-irradiation, whereas 0.70 mM VA did not modify chromosomal aberration frequencies. The lower number of chromosomal aberrations obtained when VA was employed at higher dose after γ-irradiation, could be related to the induction of a cell cycle arrest, a fact that should be taken into consideration when VA is employed in combination with physical or chemical agents. PMID:28250911

  20. Aberration-corrected STEM/TEM imaging at 15kV.

    PubMed

    Sasaki, Takeo; Sawada, Hidetaka; Hosokawa, Fumio; Sato, Yuta; Suenaga, Kazu

    2014-10-01

    The performance of aberration-corrected (scanning) transmission electron microscopy (S/TEM) at an accelerating voltage of 15kV was evaluated in a low-voltage microscope equipped with a cold-field emission gun and a higher-order aberration corrector. Aberrations up to the fifth order were corrected by the aberration measurement and auto-correction system using the diffractogram tableau method in TEM and Ronchigram analysis in STEM. TEM observation of nanometer-sized particles demonstrated that aberrations up to an angle of 50mrad were compensated. A TEM image of Si[110] exhibited lattice fringes with a spacing of 0.192nm, and the power spectrum of the image showed spots corresponding to distances of 0.111nm. An annular dark-field STEM image of Si[110] showed lattice fringes of (111) and (22¯0) planes corresponding to lattice distances of 0.314nm and 0.192nm, respectively. At an accelerating voltage of 15kV, the developed low-voltage microscope achieved atomic-resolution imaging with a small chromatic aberration and a large uniform phase.