Light adaptation alters inner retinal inhibition to shape OFF retinal pathway signaling

PubMed Central

Mazade, Reece E.

2016-01-01

The retina adjusts its signaling gain over a wide range of light levels. A functional result of this is increased visual acuity at brighter luminance levels (light adaptation) due to shifts in the excitatory center-inhibitory surround receptive field parameters of ganglion cells that increases their sensitivity to smaller light stimuli. Recent work supports the idea that changes in ganglion cell spatial sensitivity with background luminance are due in part to inner retinal mechanisms, possibly including modulation of inhibition onto bipolar cells. To determine how the receptive fields of OFF cone bipolar cells may contribute to changes in ganglion cell resolution, the spatial extent and magnitude of inhibitory and excitatory inputs were measured from OFF bipolar cells under dark- and light-adapted conditions. There was no change in the OFF bipolar cell excitatory input with light adaptation; however, the spatial distributions of inhibitory inputs, including both glycinergic and GABAergic sources, became significantly narrower, smaller, and more transient. The magnitude and size of the OFF bipolar cell center-surround receptive fields as well as light-adapted changes in resting membrane potential were incorporated into a spatial model of OFF bipolar cell output to the downstream ganglion cells, which predicted an increase in signal output strength with light adaptation. We show a prominent role for inner retinal spatial signals in modulating the modeled strength of bipolar cell output to potentially play a role in ganglion cell visual sensitivity and acuity. PMID:26912599

Perceived area and the luminosity threshold.

PubMed

Bonato, F; Gilchrist, A L

1999-07-01

Observers made forced-choice opaque/luminous responses to targets of varying luminance and varying size presented (1) on the wall of a laboratory, (2) as a disk within an annulus, and (3) embedded within a Mondrian array presented within a vision tunnel. Lightness matches were also made for nearby opaque surfaces. The results show that the threshold luminance value at which a target begins to appear self-luminous increases with its size, defined as perceived size, not retinal size. More generally, the larger the target, the more an increase in its luminance induces grayness/blackness into the surround and the less it induces luminosity into the target, and vice versa. Corresponding to this luminosity/grayness tradeoff, there appears to be an invariant: Across a wide variety of conditions, a target begins to appear luminous when its luminance is about 1.7 times that of a surface that would appear white in the same illumination. These results show that the luminosity threshold behaves like a surface lightness value--the maximum lightness value, in fact--and is subject to the same laws of anchoring (such as the area rule proposed by Li & Gilchrist, 1999) as surface lightness.

Generalized image contrast enhancement technique based on the Heinemann contrast discrimination model

NASA Astrophysics Data System (ADS)

Liu, Hong; Nodine, Calvin F.

1996-07-01

This paper presents a generalized image contrast enhancement technique, which equalizes the perceived brightness distribution based on the Heinemann contrast discrimination model. It is based on the mathematically proven existence of a unique solution to a nonlinear equation, and is formulated with easily tunable parameters. The model uses a two-step log-log representation of luminance contrast between targets and surround in a luminous background setting. The algorithm consists of two nonlinear gray scale mapping functions that have seven parameters, two of which are adjustable Heinemann constants. Another parameter is the background gray level. The remaining four parameters are nonlinear functions of the gray-level distribution of the given image, and can be uniquely determined once the previous three are set. Tests have been carried out to demonstrate the effectiveness of the algorithm for increasing the overall contrast of radiology images. The traditional histogram equalization can be reinterpreted as an image enhancement technique based on the knowledge of human contrast perception. In fact, it is a special case of the proposed algorithm.

Threshold setting by the surround of cat retinal ganglion cells.

PubMed

Barlow, H B; Levick, W R

1976-08-01

1. The slope of curves relating the log increment threshold to log background luminance in cat retinal ganglion cells is affected by the area and duration of the test stimulus, as it is in human pyschophysical experiments. 2. Using large area, long duration stimuli the slopes average 0-82 and approach close to 1 (Weber's Law) in the steepest cases. Small stimuli gave an average of 0-53 for on-centre units using brief stimuli, and 0-56 for off-centre units, using long stimuli. Slopes under 0-5 (square root law) were not found over an extended range of luminances. 3. On individual units the slope was generally greater for larger and longer test stimulus, but no unit showed the full extent of change from slope of 0-5 to slope of 1. 4. The above differences hold for objective measures of quantum/spike ratio, as well as for thresholds either judged by ear or assessed by calculation. 5. The steeper slope of the curves for large area, long duration test stimuli compared with small, long duration stimuli, is associated with the increased effectiveness of antagonism from the surround at high backgrounds. This change may be less pronounced in off-centre units, one of which (probably transient Y-type) showed no difference of slope, and gave parallel area-threshold curves at widely separated background luminances, confirming the importance of differential surround effectiveness in changing the slope of the curves. 6. In on-centre units, the increased relative effectiveness of the surround is associated with the part of the raised background light that falls on the receptive field centre. 7. It is suggested that the variable surround functions as a zero-offset control that sets the threshold excitation required for generating impulses, and that this is separate from gain-setting adaptive mechanisms. This may be how ganglion cells maintain high incremental sensitivity in spite of a strong maintained excitatory drive that would otherwise cause compressive response non-linearities.

Effects of surround articulation on lightness depend on the spatial arrangement of the articulated region

NASA Astrophysics Data System (ADS)

Zemach, Iris K.; Rudd, Michael E.

2007-07-01

We investigated the effect of surround articulation on the perceived lightness of a target disk. Surround articulation was manipulated by varying either the number of wedges in a surround consisting of wedges of alternating luminance or the number of checks in a surround consisting of a radial checkerboard pattern. In most conditions, increased articulation caused incremental targets to appear lighter and decremental targets to appear darker. But increasing the surround articulation in a way that did not increase the number of target-coaligned edges in the display did not affect the target lightness. We propose that the effects of surround articulation depend on the relationship between the orientations and contrast polarities of the target edges and those of edges present within the surround.

NGC 1614: A Laboratory for Starburst Evolution

NASA Technical Reports Server (NTRS)

Alonso-Herrero, A.; Engelbracht, C. W.; Rieke, M. J.; Rieke, G. H.; Quillen, A. C.

2000-01-01

The modest extinction and reasonably face-on viewing geometry make the luminous infrared galaxy NGC 1614 an ideal laboratory for study of a powerful starburst. HST/NICMOS observations show: (1) deep CO stellar absorption, tracing a starburst nucleus about 45 pc in diameter; (2) surrounded by an approx. 600 pc diameter ring of supergiant H II regions revealed in Pa-alpha line emission; (3) lying within a molecular ring indicated by its extinction shadow in H - K; and (4) all at the center of a disturbed spiral galaxy. The luminosities of the giant H II regions in the ring axe extremely high, an order of magnitude brighter than 30 Doradus; very luminous H II regions, comparable with 30 Dor, are also found in the spiral arms of the galaxy. Luminous stellar clusters surround the nucleus and lie in the spiral arms, similar to clusters observed in other infrared luminous and ultraluminous galaxies. The star forming activity may have been initiated by a merger between a disk galaxy and a companion satellite, whose nucleus appears in projection about 300 pc to the NE of the nucleus of the primary galaxy. The relation of deep stellar CO bands to surrounding ionized gas ring to molecular gas indicates that the luminous starburst started in the nucleus and is propagating outward into the surrounding molecular ring. This hypothesis is supported by evolutionary starburst modeling that shows that the properties of NGC 1614 can be fitted with two short-lived bursts of star formation separated by 5 Myr (and by inference by a variety of models with a similar duration of star formation). The total dynamical mass of the starburst region of 1.3 x 10(exp 9) solar masses is mostly accounted for by the old pre-starburst stellar population. Although our starburst models use a modified Salpeter initial mass function (turning over near one solar mass), the tight mass budget suggests that the IMF may contain relatively more 10 - 30 solar masses stars and fewer low mass stars than the Salpeter function. The dynamical mass is nearly four times smaller than the mass of molecular gas estimated from the standard ratio of (C-12)O (1 - 0) to H2. A number of arguments place the mass of gas in the starburst region at approx. 25% of the dynamical mass, nominally about 1/15 and with an upper limit of 1/10 of the amount estimated from (C-12)O and the standard ratio.

Geometry of illumination, luminance contrast, and gloss perception.

PubMed

Leloup, Frédéric B; Pointer, Michael R; Dutré, Philip; Hanselaer, Peter

2010-09-01

The influence of both the geometry of illumination and luminance contrast on gloss perception has been examined using the method of paired comparison. Six achromatic glass samples having different lightness were illuminated by two light sources. Only one of these light sources was visible in reflection by the observer. By separate adjustment of the intensity of both light sources, the luminance of both the reflected image and the adjacent off-specular surroundings could be individually varied. It was found that visual gloss appraisal did not correlate with instrumentally measured specular gloss; however, psychometric contrast seemed to be a much better correlate. It has become clear that not only the sample surface characteristics determine gloss perception: the illumination geometry could be an even more important factor.

Traffic Signs in Complex Visual Environments

DOT National Transportation Integrated Search

1982-11-01

The effects of sign luminance on detection and recognition of traffic control devices is mediated through contrast with the immediate surround. Additionally, complex visual scenes are known to degrade visual performance with targets well above visual...

Immunohistochemical localisation of keratin and luminal epithelial antigen in myoepithelial and luminal epithelial cells of human mammary and salivary gland tumours.

PubMed

Nathrath, W B; Wilson, P D; Trejdosiewicz, L K

1982-01-01

Rabbit antisera to human 40-63 000 MW epidermal keratin, one batch with restricted distribution of reactivity from an initial (aK1) and one with "broad spectrum" distribution of reactivity from a late bleeding (aK), and to "luminal epithelial antigen" (aLEA) were applied to formalin fixed paraffin embedded sections of human normal and neoplastic mammary and salivary glands using an indirect immunoperoxidase method. aK1 reacted with myoepithelial cells, aLEA with luminal epithelial cells and aK with both cell types in normal mammary and salivary gland. In breast carcinomas the majority of intraluminal and infiltrating carcinoma cells reacted with aLEA but not with aK1 which reacted only with surrounding myoepithelial cells. aK reacted with both myoepithelial cells and with intraluminal and infiltrating tumour cells. In the salivary gland adenomas the majority of cells reacted with aK, and those cells arranged in a tubular fashion reacted with aLEA.

Camouflage predicts survival in ground-nesting birds

PubMed Central

Troscianko, Jolyon; Wilson-Aggarwal, Jared; Stevens, Martin; Spottiswoode, Claire N.

2016-01-01

Evading detection by predators is crucial for survival. Camouflage is therefore a widespread adaptation, but despite substantial research effort our understanding of different camouflage strategies has relied predominantly on artificial systems and on experiments disregarding how camouflage is perceived by predators. Here we show for the first time in a natural system, that survival probability of wild animals is directly related to their level of camouflage as perceived by the visual systems of their main predators. Ground-nesting plovers and coursers flee as threats approach, and their clutches were more likely to survive when their egg contrast matched their surrounds. In nightjars – which remain motionless as threats approach – clutch survival depended on plumage pattern matching between the incubating bird and its surrounds. Our findings highlight the importance of pattern and luminance based camouflage properties, and the effectiveness of modern techniques in capturing the adaptive properties of visual phenotypes. PMID:26822039

Camouflage predicts survival in ground-nesting birds.

PubMed

Troscianko, Jolyon; Wilson-Aggarwal, Jared; Stevens, Martin; Spottiswoode, Claire N

2016-01-29

Evading detection by predators is crucial for survival. Camouflage is therefore a widespread adaptation, but despite substantial research effort our understanding of different camouflage strategies has relied predominantly on artificial systems and on experiments disregarding how camouflage is perceived by predators. Here we show for the first time in a natural system, that survival probability of wild animals is directly related to their level of camouflage as perceived by the visual systems of their main predators. Ground-nesting plovers and coursers flee as threats approach, and their clutches were more likely to survive when their egg contrast matched their surrounds. In nightjars - which remain motionless as threats approach - clutch survival depended on plumage pattern matching between the incubating bird and its surrounds. Our findings highlight the importance of pattern and luminance based camouflage properties, and the effectiveness of modern techniques in capturing the adaptive properties of visual phenotypes.

Intraoperative Fluorescence Cerebral Angiography by Laser Surgical Microscopy: Comparison With Xenon Microscopy and Simultaneous Observation of Cerebral Blood Flow and Surrounding Structures.

PubMed

Ito, Yuhei; Suzuki, Kyouichi; Ichikawa, Tsuyoshi; Watanabe, Yoichi; Sato, Taku; Sakuma, Jun; Saito, Kiyoshi

2018-06-12

Laser surgical microscopes should enable uniform illumination of the operative field, and require less luminous energy compared with existing xenon surgical microscopes. To examine the utility of laser illumination in fluorescence cerebral angiography. Fluorescein sodium (fluorescein) was used as a fluorescent dye. We first compared the clarity of cerebral blood flow images collected by fluorescence angiography between the laser illumination and xenon illumination methods. We then assessed use of the laser illuminator for simultaneous observation of blood flow and surrounding structures during fluorescence angiography. Furthermore, the study was designed to evaluate usefulness of the thus determined excitation light in clinical cases. Fluorescence angiography using blue light laser for excitation provided higher clarity and contrast blood flow images compared with using blue light generated from a xenon lamp. Further, illumination with excitation light consisting of a combination of 3 types of laser (higher level of blue light, no green light, and lower level of red light) enabled both blood flow and surrounding structures to be observed through the microscope directly by the surgeon. Laser-illuminated fluorescence angiography provides high clarity and contrast images of cerebral blood flow. Further, a laser providing strong blue light and weak red light for excitation light enables simultaneous visual observation of fluorescent blood flow and surrounding structures by the surgeon using a surgical microscope. Overall, these data suggest that laser surgical microscopes are useful for both ordinary operative manipulations and fluorescence angiography.

The place of white in a world of grays: a double-anchoring theory of lightness perception.

PubMed

Bressan, Paola

2006-07-01

The specific gray shades in a visual scene can be derived from relative luminance values only when an anchoring rule is followed. The double-anchoring theory I propose in this article, as a development of the anchoring theory of Gilchrist et al. (1999), assumes that any given region (a) belongs to one or more frameworks, created by Gestalt grouping principles, and (b) is independently anchored, within each framework, to both the highest luminance and the surround luminance. The region's final lightness is a weighted average of the values computed, relative to both anchors, in all frameworks. The new model accounts not only for all lightness illusions that are qualitatively explained by the anchoring theory but also for a number of additional effects, and it does so quantitatively, with the support of mathematical simulations. ((c) 2006 APA, all rights reserved).

Effect of Background Luminance Level on the Assessment of Color Visual Acuity Using Colored Landolt Rings in Young Healthy Subjects.

PubMed

Tanaka, Yoshiki; Yokoyama, Sho; Horai, Rie; Kojima, Takashi; Hiroyuki, Sato; Kato, Yukihito; Takagi, Mari; Nakamura, Hideki; Tanaka, Kiyoshi; Ichikawa, Kazuo; Tanabe, Shoko

2018-03-01

To evaluate the color visual acuity (CVA) of young healthy subjects using colored Landolt rings and the effect of background luminance level on the CVA. We measured the CVA of 20 young healthy subjects (age: 23.8 ± 3.8 years) with different colors using a computer and a liquid crystal display, with 15 Landolt ring colors (30 cd/m 2 ) with a background luminance of 30 cd/m 2 , and then 100 cd/m 2 . We then used different background luminance levels (15-50 cd/m 2 ) using four Landolt ring colors (red, green-yellow, green, and blue-green) to evaluate the effect of the background luminance level on CVA. The CVA significantly differed among the colors with a background luminance of 30 cd/m 2 (p < 0.0001). Green-yellow and blue-purple had poor CVA (high LogMAR value; 0.808 ± 0.107 and 0.633 ± 0.150, respectively) with a background luminance of 30 cd/m 2 (same luminance as the Landolt rings). There were no significant differences in the CVAs among the colors with a background luminance of 100 cd/m 2 (p = 0.5999). There were no significant difference in the CVA between background luminance 30 cd/m 2 and other luminance level ranging from 28 to 32 cd/m 2 for colors of red, green-yellow, green, and blue-green. The results reveal that the background luminance of Landolt rings affects the CVA. Distinctive CVAs for each color are measured by equalizing the luminance between the Landolt ring and the background. We consider that the poor CVAs of these colors reflect the visual function of S-cone, because GY and BP are included in the confusion locus of tritan axis on the chromaticity diagram. We believe that CVA assessment may be useful for individuals who have known or suspected ocular dysfunction or color vision deficiencies.

The Anatomy and Morphology of the Adult Bacterial Light Organ of Euprymna scolopes Berry (Cephalopoda:Sepiolidae).

PubMed

McFall-Ngai, M; Montgomery, M K

1990-12-01

The sepiolid squid, Euprymna scolopes, has a bilobed luminous organ in the center of the mantle cavity, associated with the ink sac. Luminous bacterial symbionts (Vibrio fischeri) are housed in narrow channels of host epithelial tissue. The channels of each lobe of the light organ empty into a ciliated duct, which is contiguous with the mantle cavity of the squid. Surrounding the symbiotic bacteria and their supportive host cells are host tissues recruited into the light organ system, including a muscle-derived lens and thick reflector that appear to permit the squid to control the quality of bacterial light emission.

A Review of Research Related to Unmanned Aircraft System Visual Observers

DTIC Science & Technology

2014-10-01

accommodation. Poor Contrast Contrast refers to the difference in luminance between an object and its background. The larger the difference in luminance , the...to camouflage potential targets. Complex Backgrounds When the background behind an object contains a variety of luminance levels and contours it...itself contained a variety of luminance levels and contours. It is likely that this complex background effect would be seen more often between air

Neuronal nonlinearity explains greater visual spatial resolution for darks than lights.

PubMed

Kremkow, Jens; Jin, Jianzhong; Komban, Stanley J; Wang, Yushi; Lashgari, Reza; Li, Xiaobing; Jansen, Michael; Zaidi, Qasim; Alonso, Jose-Manuel

2014-02-25

Astronomers and physicists noticed centuries ago that visual spatial resolution is higher for dark than light stimuli, but the neuronal mechanisms for this perceptual asymmetry remain unknown. Here we demonstrate that the asymmetry is caused by a neuronal nonlinearity in the early visual pathway. We show that neurons driven by darks (OFF neurons) increase their responses roughly linearly with luminance decrements, independent of the background luminance. However, neurons driven by lights (ON neurons) saturate their responses with small increases in luminance and need bright backgrounds to approach the linearity of OFF neurons. We show that, as a consequence of this difference in linearity, receptive fields are larger in ON than OFF thalamic neurons, and cortical neurons are more strongly driven by darks than lights at low spatial frequencies. This ON/OFF asymmetry in linearity could be demonstrated in the visual cortex of cats, monkeys, and humans and in the cat visual thalamus. Furthermore, in the cat visual thalamus, we show that the neuronal nonlinearity is present at the ON receptive field center of ON-center neurons and ON receptive field surround of OFF-center neurons, suggesting an origin at the level of the photoreceptor. These results demonstrate a fundamental difference in visual processing between ON and OFF channels and reveal a competitive advantage for OFF neurons over ON neurons at low spatial frequencies, which could be important during cortical development when retinal images are blurred by immature optics in infant eyes.

Imaging AGN Feedback in NGC 3393 with CHEERS

NASA Astrophysics Data System (ADS)

Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Wang, Junfeng; Storchi-Bergmann, Thaisa

2016-01-01

The CHandra Extended Emission-line Region Survey (CHEERS) is the 'ultimate' resolution X-ray imaging survey of nearby far-IR selected AGN. By comparing deep Chandra observations with complementary HST and radio data, we investigate the morphology of the extended narrow-line region on scales of <100 pc. We present new results on the gas surrounding the compton-thick AGN NGC 3393. The luminous extended narrow-line X-ray emission from this gas allows us to study the role and extent of AGN feedback as sub-kpc jets interact with the surrounding ISM.

Imaging AGN Feedback in NGC 3393 with CHEERS

NASA Astrophysics Data System (ADS)

Paggi, Alessandro; Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Wang, Junfeng; Storchi-Bergmann, Thaisa

2016-04-01

The CHandra Extended Emission-line Region Survey (CHEERS) is the 'ultimate' resolution X-ray imaging survey of nearby far-IR selected AGN. By comparing deep Chandra observations with complementary HST and radio data, we investigate the morphology of the extended narrow-line region on scales of <100 pc. We present new results on the gas surrounding the compton-thick AGN NGC 3393. The luminous extended narrow-line X-ray emission from this gas allows us to study the role and extent of AGN feedback as sub-kpc jets interact with the surrounding ISM.

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

PubMed Central

Hong, Sang Wook; Shevell, Steven K.

2008-01-01

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

The Effect of Light Level and Small Pupils on Presbyopic Reading Performance.

PubMed

Xu, Renfeng; Gil, Daniel; Dibas, Mohammed; Hare, William; Bradley, Arthur

2016-10-01

To examine the impact of small pupils and light levels on reading performance of distance-corrected presbyopes. To determine whether small pupils would enable presbyopes to read at near even at low light levels. To establish the lower range of text luminances, we quantified the space-averaged luminance of text in nine different artificially lit interior environments, and examined the impact of the text characters on space-averaged luminance of electronic and printed displays. Distance and near reading speeds of 20 presbyopes (ages 40-60 years) were measured while viewing through artificial pupils (diameters 1-4.5 mm), natural pupils, or with a multifocal contact lens. Space-averaged text luminance levels varied from 0.14 to 140 cd/m2 (including the range of measured environmental text luminances). Adding black text to a white computer display or paper reduces luminance by approximately 15% to 31%, and the lowest encountered environmental text luminance was approximately 2 to 3 cd/m2. For both distance and near reading performance, the 2- to 3-mm small pupil yielded the best overall reading acuity for space-averaged text light levels ≥ 2 cd/m2. The 2- to 3-mm artificial pupils and the multifocal contact lenses both enabled maximum or near-maximum reading speeds for 0.5 logMAR characters at distance and near, but with natural pupils, reading speeds were significantly reduced at near. Although photon noise at low luminance reduces the visual benefits of small pupils, the benefits of 2- to 3-mm artificial pupils are sufficient to enable >80% of distance-corrected presbyopes to read proficiently at near, even at the lowest text luminances found in interior environments.

Strong stellar winds.

PubMed

Conti, P S; McCray, R

1980-04-04

The hottest and most luminous stars lose a substantial fraction of their mass in strong stellar winds. These winds not only affect the evolution of the star, they also carve huge expanding cavities in the surrounding interstellar medium, possibly affecting star formation. The winds are probably driven by radiation pressure, but uncertainties persist in their theoretical description. Strong x-ray sources associated with a few of these hot stars may be used to probe the stellar winds. The nature of the weak x-ray sources recently observed to be associated with many of these stars is uncertain. It is suggested that roughly 10 percent of the luminous hot stars may have as companions neutron stars or black holes orbiting within the stellar winds.

Dynamics of backlight luminance for using smartphone in dark environment

NASA Astrophysics Data System (ADS)

Na, Nooree; Jang, Jiho; Suk, Hyeon-Jeong

2014-02-01

This study developed dynamic backlight luminance, which gradually changes as time passes for comfortable use of a smartphone display in a dark environment. The study was carried out in two stages. In the first stage, a user test was conducted to identify the optimal luminance by assessing the facial squint level, subjective glare evaluation, eye blink frequency and users' subjective preferences. Based on the results of the user test, the dynamics of backlight luminance was designed. It has two levels of luminance: the optimal level for initial viewing to avoid sudden glare or fatigue to users' eyes, and the optimal level for constant viewing, which is comfortable, but also bright enough for constant reading of the displayed material. The luminance for initial viewing starts from 10 cd/m2, and it gradually increases to 40 cd/m2 for users' visual comfort at constant viewing for 20 seconds; In the second stage, a validation test on dynamics of backlight luminance was conducted to verify the effectiveness of the developed dynamics. It involving users' subjective preferences, eye blink frequency, and brainwave analysis using the electroencephalogram (EEG) to confirm that the proposed dynamic backlighting enhances users' visual comfort and visual cognition, particularly for using smartphones in a dark environment.

Interactions of X-ray Binaries with Their Surrounding Material

NASA Astrophysics Data System (ADS)

Servillat, Mathieu; Chaty, S.; Coleiro, A.; Tang, S.; Grindlay, J. E.; Los, E.

2013-04-01

We can observe the interactions of high mass X-ray binaries with their surrounding material in two complementary ways: variability over long time scales, and direct infrared observation of dust/gas. This gives unprecedented clues on the formation and evolution of those systems. Using Herschel infrared observations of high mass X-ray binaries and of ultra-luminous X-ray sources, we aim to detect and characterize the surrounding material. In the case of ultra-luminous X-ray sources, due to the enormous amount of energy radiated, strong interactions with their environment are expected, particularly if the emission is not beamed and if they host an intermediate mass black hole. This provides a unique test for the existence of such objects. The Digital Access to a Sky Century at Harvard (DASCH) is a project to digitize and analyze the scientific data contained in the 530 000 Harvard College Observatory plates taken between the 1880s and 1990s, which is a unique resource for studying temporal variations in the universe on 10-100 yr timescales. The Be star SAO 49275 shows significant slow variability of 1 magnitude on time scales 10-50 years. This variability seems connected to the formation and disappearance of the decretion disk of the Be star, maybe triggered by the presence of a compact object companion, possibly a white dwarf.

Gene expression abnormalities in histologically normal breast epithelium from patients with luminal type of breast cancer.

PubMed

Zubor, Pavol; Hatok, Jozef; Moricova, Petra; Kajo, Karol; Kapustova, Ivana; Mendelova, Andrea; Racay, Peter; Danko, Jan

2015-05-01

The gene expression profile of breast cancer has been described as a great breakthrough on the way to comprehend differences in cancer origin, behavior and therapy. However, gene expression profile in histologically normal epithelium (HNEpi) which could harbor genetic abnormalities predisposing breast tissue to develop malignancy was minor scope for scientists in the past. Thus, we aimed to analyze gene expressions in HNEpi and breast cancer tissue (BCTis) in order to establish its value as potential diagnostic marker for cancer development. We evaluated a panel of disease-specific genes in luminal type (A/B) of breast cancer and tumor surrounding HNEpi by qRT-PCR Array in 32 microdissected samples. There was 20.2 and 2.4% deregulation rate in genes with at least 2-fold or 5-fold over-expression between luminal (A/B) type breast carcinomas and tumor surrounding HNEpi, respectively. The high-grade luminal carcinomas showed higher number of deregulated genes compared to low-grade cases (50.6 vs. 23.8% with at least 2-fold deregulation rate). The main overexpressed genes in HNEpi were KLK5, SCGB1D2, GSN, EGFR and NGFR. The significant differences in gene expression between BCTis and HNEpi samples were revealed for BAG1, C3, CCNA2, CD44, FGF1, FOSL1, ID2, IL6R, NGFB, NGFR, PAPPA, PLAU, SERPINB5, THBS1 and TP53 gene (p < 0.05) and BCL2L2, CTSB, ITGB4, JUN, KIT, KLF5, SCGB1D2, SCGB2A1, SERPINE1 (p < 0.01), and EGFR, GABRP, GSN, MAP2K7 and THBS2 (p < 0.001), and GSN, KLK5 (p < 0.0001). The ontological gene analyses revealed high deregulations in gene group directly associated with breast cancer prognosis and origin.

An evaluation of organic light emitting diode monitors for medical applications: Great timing, but luminance artifacts

PubMed Central

Elze, Tobias; Taylor, Christopher; Bex, Peter J.

2013-01-01

Purpose: In contrast to the dominant medical liquid crystal display (LCD) technology, organic light-emitting diode (OLED) monitors control the display luminance via separate light-emitting diodes for each pixel and are therefore supposed to overcome many previously documented temporal artifacts of medical LCDs. We assessed the temporal and luminance characteristics of the only currently available OLED monitor designed for use in the medical treatment field (SONY PVM2551MD) and checked the authors’ main findings with another SONY OLED device (PVM2541). Methods: Temporal properties of the photometric output were measured with an optical transient recorder. Luminances of the three color primaries and white for all 256 digital driving levels (DDLs) were measured with a spectroradiometer. Between the luminances of neighboring DDLs, just noticeable differences were calculated according to a perceptual model developed for medical displays. Luminances of full screen (FS) stimuli were compared to luminances of smaller stimuli with identical DDLs. Results: All measured luminance transition times were below 300 μs. Luminances were independent of the luminance in the preceding frame. However, for the single color primaries, up to 50.5% of the luminances of neighboring DDLs were not perceptually distinguishable. If two color primaries were active simultaneously, between 36.7% and 55.1% of neighboring luminances for increasing DDLs of the third primary were even decreasing. Moreover, luminance saturation effects were observed when too many pixels were active simultaneously. This effect was strongest for white; a small white patch was close to 400 cd/m2, but in FS the luminance of white saturated at 162 cd/m2. Due to different saturation levels, the luminance of FS green and FS yellow could exceed the luminance of FS white for identical DDLs. Conclusions: The OLED temporal characteristics are excellent and superior to those of LCDs. However, the OLEDs revealed severe perceptually relevant artifacts with implications for applicability to medical imaging. PMID:24007183

An evaluation of organic light emitting diode monitors for medical applications: great timing, but luminance artifacts.

PubMed

Elze, Tobias; Taylor, Christopher; Bex, Peter J

2013-09-01

In contrast to the dominant medical liquid crystal display (LCD) technology, organic light-emitting diode (OLED) monitors control the display luminance via separate light-emitting diodes for each pixel and are therefore supposed to overcome many previously documented temporal artifacts of medical LCDs. We assessed the temporal and luminance characteristics of the only currently available OLED monitor designed for use in the medical treatment field (SONY PVM2551MD) and checked the authors' main findings with another SONY OLED device (PVM2541). Temporal properties of the photometric output were measured with an optical transient recorder. Luminances of the three color primaries and white for all 256 digital driving levels (DDLs) were measured with a spectroradiometer. Between the luminances of neighboring DDLs, just noticeable differences were calculated according to a perceptual model developed for medical displays. Luminances of full screen (FS) stimuli were compared to luminances of smaller stimuli with identical DDLs. All measured luminance transition times were below 300 μs. Luminances were independent of the luminance in the preceding frame. However, for the single color primaries, up to 50.5% of the luminances of neighboring DDLs were not perceptually distinguishable. If two color primaries were active simultaneously, between 36.7% and 55.1% of neighboring luminances for increasing DDLs of the third primary were even decreasing. Moreover, luminance saturation effects were observed when too many pixels were active simultaneously. This effect was strongest for white; a small white patch was close to 400 cd/m(2), but in FS the luminance of white saturated at 162 cd/m(2). Due to different saturation levels, the luminance of FS green and FS yellow could exceed the luminance of FS white for identical DDLs. The OLED temporal characteristics are excellent and superior to those of LCDs. However, the OLEDs revealed severe perceptually relevant artifacts with implications for applicability to medical imaging.

MINIMAL ENDOILLUMINATION LEVELS AND DISPLAY LUMINOUS EMITTANCE DURING THREE-DIMENSIONAL HEADS-UP VITREORETINAL SURGERY.

PubMed

Adam, Murtaza K; Thornton, Sarah; Regillo, Carl D; Park, Carl; Ho, Allen C; Hsu, Jason

2017-09-01

To determine minimal endoillumination levels required to perform 3-dimensional heads-up vitreoretinal surgery and to correlate endoillumination levels used for measurements of heads-up display (HUD) luminous emittance. Prospective, observational surgical case series of 10 patients undergoing vitreoretinal surgery. Endoillumination levels were set to 40% of maximum output and were decreased at set intervals until the illumination level was 0%. Corresponding luminous emittance (lux) of the HUD was measured 40 cm from the display using a luxmeter (Dr. Meter, Model #LX1010BS). In 9 of 10 cases, the surgeon felt that they could operate comfortably at an endoillumination level of 10% of maximum output with corresponding HUD emittance of 14.3 ± 9.5 lux. In the remaining case, the surgeon felt comfortable at a 3% endoillumination level with corresponding HUD emittance of 15 lux. Below this threshold, subjective image dimness and digital noise limited visibility. Endoillumination levels were correlated with luminous emittance from the 3-dimensional HUD (P < 0.01). The average coefficient of variation of HUD luminance was 0.546. There were no intraoperative complications. With real-time digital processing and automated brightness control, 3-dimensional HUD platforms may allow for reduced intraoperative endoillumination levels and a theoretically reduced risk of retinal phototoxicity during vitreoretinal surgery.

Development and evaluation of a method of calibrating medical displays based on fixed adaptation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sund, Patrik, E-mail: patrik.sund@vgregion.se; Månsson, Lars Gunnar; Båth, Magnus

2015-04-15

Purpose: The purpose of this work was to develop and evaluate a new method for calibration of medical displays that includes the effect of fixed adaptation and by using equipment and luminance levels typical for a modern radiology department. Methods: Low contrast sinusoidal test patterns were derived at nine luminance levels from 2 to 600 cd/m{sup 2} and used in a two alternative forced choice observer study, where the adaptation level was fixed at the logarithmic average of 35 cd/m{sup 2}. The contrast sensitivity at each luminance level was derived by establishing a linear relationship between the ten pattern contrastmore » levels used at every luminance level and a detectability index (d′) calculated from the fraction of correct responses. A Gaussian function was fitted to the data and normalized to the adaptation level. The corresponding equation was used in a display calibration method that included the grayscale standard display function (GSDF) but compensated for fixed adaptation. In the evaluation study, the contrast of circular objects with a fixed pixel contrast was displayed using both calibration methods and was rated on a five-grade scale. Results were calculated using a visual grading characteristics method. Error estimations in both observer studies were derived using a bootstrap method. Results: The contrast sensitivities for the darkest and brightest patterns compared to the contrast sensitivity at the adaptation luminance were 37% and 56%, respectively. The obtained Gaussian fit corresponded well with similar studies. The evaluation study showed a higher degree of equally distributed contrast throughout the luminance range with the calibration method compensated for fixed adaptation than for the GSDF. The two lowest scores for the GSDF were obtained for the darkest and brightest patterns. These scores were significantly lower than the lowest score obtained for the compensated GSDF. For the GSDF, the scores for all luminance levels were statistically separated from the average value; three were lower and two were higher. For the compensated GSDF, three of the scores could not be separated from the average value. Conclusions: An observer study using clinically relevant displays and luminance settings has demonstrated that the calibration of displays according to the GSDF causes the perceived contrast to be unevenly distributed when using displays with a high luminance range. As the luminance range increases, the perceived contrast in the dark and bright regions will be significantly lower than the perceived contrast in the middle of the luminance range. A new calibration method that includes the effect of fixed adaptation was developed and evaluated in an observer study and was found to distribute the contrast of the display more evenly throughout the grayscale than the GSDF.« less

Laser-activated remote phosphor light engine for projection applications

NASA Astrophysics Data System (ADS)

Daniels, Martin; Mehl, Oliver; Hartwig, Ulrich

2015-09-01

Recent developments in blue emitting laser diodes enable attractive solutions in projection applications using phosphors for efficient light conversion with very high luminance levels. Various commercially available projectors incorporating this technology have entered the market in the past years. While luminous flux levels are still comparable to lamp-based systems, lifetime expectations of classical lamp systems are exceeded by far. OSRAM GmbH has been exploring this technology for several years and has introduced the PHASER® brand name (Phosphor + laser). State-of-the-art is a rotating phosphor wheel excited by blue laser diodes to deliver the necessary primary colors, either sequentially for single-imager projection engines, or simultaneously for 3-panel systems. The PHASER® technology enables flux and luminance scaling, which allows for smaller imagers and therefore cost-efficient projection solutions. The resulting overall efficiency and ANSI lumen specification at the projection screen of these systems is significantly determined by the target color gamut and the light transmission efficiency of the projection system. With increasing power and flux level demand, thermal issues, especially phosphor conversion related, dominate the opto-mechanical system design requirements. These flux levels are a great challenge for all components of an SSL-projection system (SSL:solid-state lighting). OSRAḾs PHASER® light engine platform is constantly expanded towards higher luminous flux levels as well as higher luminance levels for various applications. Recent experiments employ blue laser pump powers of multiple 100 Watts to excite various phosphors resulting in luminous flux levels of more than 40 klm.

Shell nebulae around luminous evolved stars

NASA Technical Reports Server (NTRS)

Dufour, Reginald J.

1989-01-01

Shell nebulae around luminous Population I Wolf-Rayet, Of, and P-Cygni stars are astrophysically interesting since they are indicators of pre-supernova mass loss and how such massive stars prepare their surrounding interstellar medium prior to explosion. Some twenty-odd such nebulae are known, for which detailed study of their morphological and spectroscopic characteristics have only begun in this decade. In this paper, some of these characteristics are reviewed in general, and new observations are reported. Emphasis has been placed on several 'prototype 'objects (NGC 7635, NGC 2359, NGC 6888, and the Eta Carinae condensations) to illustrate the varied massive-star mass-loss, the physics of their winds and shell ejecta, and related nucleosynthesis effects in the compositions of the winds and shells.

Contour junctions defined by dynamic image deformations enhance perceptual transparency.

PubMed

Kawabe, Takahiro; Nishida, Shin'ya

2017-11-01

The majority of work on the perception of transparency has focused on static images with luminance-defined contour junctions, but recent work has shown that dynamic image sequences with dynamic image deformations also provide information about transparency. The present study demonstrates that when part of a static image is dynamically deformed, contour junctions at which deforming and nondeforming contours are connected facilitate the deformation-based perception of a transparent layer. We found that the impression of a transparent layer was stronger when a dynamically deforming area was adjacent to static nondeforming areas than when presented alone. When contour junctions were not formed at the dynamic-static boundaries, however, the impression of a transparent layer was not facilitated by the presence of static surrounding areas. The effect of the deformation-defined junctions was attenuated when the spatial pattern of luminance contrast at the junctions was inconsistent with the perceived transparency related to luminance contrast, while the effect did not change when the spatial luminance pattern was consistent with it. In addition, the results showed that contour completions across the junctions were required for the perception of a transparent layer. These results indicate that deformation-defined junctions that involve contour completion between deforming and nondeforming regions enhance the perception of a transparent layer, and that the deformation-based perceptual transparency can be promoted by the simultaneous presence of appropriately configured luminance and contrast-other features that can also by themselves produce the sensation of perceiving transparency.

Color Discrimination Is Affected by Modulation of Luminance Noise in Pseudoisochromatic Stimuli

PubMed Central

Cormenzana Méndez, Iñaki; Martín, Andrés; Charmichael, Teaire L.; Jacob, Mellina M.; Lacerda, Eliza M. C. B.; Gomes, Bruno D.; Fitzgerald, Malinda E. C.; Ventura, Dora F.; Silveira, Luiz C. L.; O'Donell, Beatriz M.; Souza, Givago S.

2016-01-01

Pseudoisochromatic stimuli have been widely used to evaluate color discrimination and to identify color vision deficits. Luminance noise is one of the stimulus parameters used to ensure that subject's response is due to their ability to discriminate target stimulus from the background based solely on the hue between the colors that compose such stimuli. We studied the influence of contrast modulation of the stimulus luminance noise on threshold and reaction time color discrimination. We evaluated color discrimination thresholds using the Cambridge Color Test (CCT) at six different stimulus mean luminances. Each mean luminance condition was tested using two protocols: constant absolute difference between maximum and minimum luminance of the luminance noise (constant delta protocol, CDP), and constant contrast modulation of the luminance noise (constant contrast protocol, CCP). MacAdam ellipses were fitted to the color discrimination thresholds in the CIE 1976 color space to quantify the color discrimination ellipses at threshold level. The same CDP and CCP protocols were applied in the experiment measuring RTs at three levels of stimulus mean luminance. The color threshold measurements show that for the CDP, ellipse areas decreased as a function of the mean luminance and they were significantly larger at the two lowest mean luminances, 10 cd/m2 and 13 cd/m2, compared to the highest one, 25 cd/m2. For the CCP, the ellipses areas also decreased as a function of the mean luminance, but there was no significant difference between ellipses areas estimated at six stimulus mean luminances. The exponent of the decrease of ellipse areas as a function of stimulus mean luminance was steeper in the CDP than CCP. Further, reaction time increased linearly with the reciprocal of the length of the chromatic vectors varying along the four chromatic half-axes. It decreased as a function of stimulus mean luminance in the CDP but not in the CCP. The findings indicated that visual performance using pseudoisochromatic stimuli was dependent on the Weber's contrast of the luminance noise. Low Weber's contrast in the luminance noise is suggested to have a reduced effect on chromatic information and, hence, facilitate desegregation of the hue-defined target from the background. PMID:27458404

Chromatic blur perception in the presence of luminance contrast.

PubMed

Jennings, Ben J; Kingdom, Frederick A A

2017-06-01

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

What causes IOR? Attention or perception? - manipulating cue and target luminance in either blocked or mixed condition.

PubMed

Zhao, Yuanyuan; Heinke, Dietmar

2014-12-01

Inhibition of return (IOR) refers to the performance disadvantage when detecting a target presented at a previously cued location. The current paper contributes to the long-standing debate whether IOR is caused by attentional processing or perceptual processing. We present a series of four experiments which varied the cue luminance in mixed and blocked conditions. We hypothesised that if inhibition was initialized by an attentional process the size of IOR should not vary in the blocked condition as participants should be able to adapt to the level of cue luminance. However, if a perceptual process triggers inhibition both experimental manipulations should lead to varying levels of IOR. Indeed, we found evidence for the latter hypothesis. In addition, we also varied the target luminance in blocked and mixed condition. Both manipulations, cue luminance and target luminance, affected IOR in an additive fashion suggesting that the two stimuli affect human behaviour on different processing stages. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Progenitor of Tycho’s Supernova was Not Hot and Luminous

NASA Astrophysics Data System (ADS)

Ghavamian, Parviz; Woods, T. E.; Gilfanov, M.; Badenes, C.; T. E. Woods, C. Badenes, M. Gilfanov

2018-01-01

Canonical accretion models of Type Ia supernovae predict that a hot and luminous progenitor will ionize the surrounding gas out to a radius of ∼10–100 pc for ∼100,000 years after the explosion. Tycho’s supernova of 1572 was a Type Ia explosion which produced a remnant that is currently interacting with neutral gas in the form of Balmer-dominated shocks. From analysis of these shocks and photoionization calculations, we have placed stringent upper limits on the temperature and luminosity of the progenitor of Tycho’s supernova. Hot, luminous progenitors that would have produced a greater hydrogen ionization fraction than that measured at the current SNR radius (∼3 parsecs) can thus be excluded. This rules out steadily nuclear-burning white dwarfs (i..e, supersoft X-ray sources), as well as disk emission from a Chandrasekhar-mass white dwarf accreting 1E-8 solar masses per year (recurrent novae). The lack of a Stromgren sphere around Tycho’s SNR is consistent with a double degenerate explosion, although other more exotic scenarios may be possible.

Luminal epithelium in endometrial fragments affects their vascularization, growth and morphological development into endometriosis-like lesions in mice.

PubMed

Feng, Dilu; Menger, Michael D; Wang, Hongbo; Laschke, Matthias W

2014-02-01

In endometriosis research, endometriosis-like lesions are usually induced in rodents by transplantation of isolated endometrial tissue fragments to ectopic sites. In the present study, we investigated whether this approach is affected by the cellular composition of the grafts. For this purpose, endometrial tissue fragments covered with luminal epithelium (LE(+)) and without luminal epithelium (LE(-)) were transplanted from transgenic green-fluorescent-protein-positive (GFP(+)) donor mice into the dorsal skinfold chamber of GFP(-) wild-type recipient animals to analyze their vascularization, growth and morphology by means of repetitive intravital fluorescence microscopy, histology and immunohistochemistry during a 14-day observation period. LE(-) fragments developed into typical endometriosis-like lesions with cyst-like dilated endometrial glands and a well-vascularized endometrial stroma. In contrast, LE(+) fragments exhibited a polypoid morphology and a significantly reduced blood perfusion after engraftment, because the luminal epithelium prevented the vascular interconnection with the microvasculature of the surrounding host tissue. This was associated with a markedly decreased growth rate of LE(+) lesions compared with LE(-) lesions. In addition, we found that many GFP(+) microvessels grew outside the LE(-) lesions and developed interconnections to the host microvasculature, indicating that inosculation is an important mechanism in the vascularization process of endometriosis-like lesions. Our findings demonstrate that the luminal epithelium crucially affects the vascularization, growth and morphology of endometriosis-like lesions. Therefore, it is of major importance to standardize the cellular composition of endometrial grafts in order to increase the validity and reliability of pre-clinical rodent studies in endometriosis research.

An Evaluation of Performance Characteristics of Primary Display Devices.

PubMed

Ekpo, Ernest U; McEntee, Mark F

2016-04-01

The aim of this study was to complete a full evaluation of the new EIZO RX850 liquid crystal display and compare it to two currently used medical displays in Australia (EIZO GS510 and Barco MDCG 5121). The American Association of Physicists in Medicine (AAPM) Task Group 18 Quality Control test pattern was used to assess the performance of three high-resolution primary medical displays: EIZO RX850, EIZO GS510, and Barco MDCG 5121. A Konica Minolta spectroradiometer (CS-2000) was used to assess luminance response, non-uniformity, veiling glare, and color uniformity. Qualitative evaluation of noise was also performed. Seven breast lesions were displayed on each monitor and photographed with a calibrated 5.5-MP Olympus E-1 digital SLR camera. ImageJ software was used to sample pixel information from each lesion and surrounding background to calculate their conspicuity index on each of the displays. All monitor fulfilled all AAPM acceptance criteria. The performance characteristics for EIZO RX850, Barco MDCG 5121, and EIZO GS510 respectively were as follows: maximum luminance (490, 500.5, and 413 cd/m(2)), minimum luminance (0.724, 1.170, and 0.92 cd/m(2)), contrast ratio (675:1, 428:1, 449:1), just-noticeable difference index (635, 622, 609), non-uniformity (20, 5.92, and 8.5 %), veiling glare (GR = 2465.6, 720.4, 1249.8), and color uniformity (Δu'v' = +0.003, +0.002, +0.002). All monitors demonstrated low noise levels. The conspicuity index (χ) of the lesions was slightly higher in the EIZO RX850 display. All medical displays fulfilled AAPM performance criteria, and performance characteristics of EIZO RX850 are equal to or better than those of the Barco MDCG 5121 and EIZO GS510 displays.

Effects of color combination and ambient illumination on visual perception time with TFT-LCD.

PubMed

Lin, Chin-Chiuan; Huang, Kuo-Chen

2009-10-01

An empirical study was carried out to examine the effects of color combination and ambient illumination on visual perception time using TFT-LCD. The effect of color combination was broken down into two subfactors, luminance contrast ratio and chromaticity contrast. Analysis indicated that the luminance contrast ratio and ambient illumination had significant, though small effects on visual perception. Visual perception time was better at high luminance contrast ratio than at low luminance contrast ratio. Visual perception time under normal ambient illumination was better than at other ambient illumination levels, although the stimulus color had a confounding effect on visual perception time. In general, visual perception time was better for the primary colors than the middle-point colors. Based on the results, normal ambient illumination level and high luminance contrast ratio seemed to be the optimal choice for design of workplace with video display terminals TFT-LCD.

Constancy of built-in luminance meter measurements in diagnostic displays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silosky, M., E-mail: michael.silosky@ucdenver.edu; Marsh, R. M.

2013-12-15

Purpose: Liquid crystal displays used to interpret medical images are often equipped with built-in luminance meters to evaluate luminance response and Grayscale Standard Display Function conformance. This work evaluates agreement between luminance reported by the built-in meters and external measurements. Methods: The white level luminance was measured using a built-in meter and an external meter for 93 primary review workstations (Models MFGD 3420 and MDCG 3120-CB) with between 117 and 49 336 backlight hours (BLH). Measured luminance values were compared viat-test for displays with less than 25 000 BLH and those with more than 25 000 BLH. Bias between meters was also evaluated.more » Changes in luminance uniformity with increasing backlight hours were explored by determining the maximum luminance deviation (MLD) for subsets of these displays with less than 800 BLH and greater than 35 000 BLH. Results: The mean difference between built-in and external luminance measurements was 5.84% and 38.92% for displays with less than 25 000 and greater than 25 000 BLH, respectively, with a statistically significant difference in the means (p < 0.001). For displays with low BLH, a statistically significant bias was observed (p < 0.001) between built-in and external measurements. A high degree of correlation was observed between measurements made with two separate external meters (r = 0.999). The mean MLD was 9.5% and 11.2% for MDCG 3120-CB displays with less than 800 and greater than 35 000 BLH, respectively. The difference in the mean values was not statistically significant (p < 0.001). Conclusions: Disagreement between the white level luminance measured using the built-in and external meter increased with BLH. Consequently, reliance on values reported by the built-in luminance meter may result in a reduction in image contrast with time. Recommendations have been proposed regarding luminance response testing and corrective action for failing displays.« less

Unveiling the hearts of luminous and ultra-luminous infrared galaxy mergers with laser guide star adaptive optics

NASA Astrophysics Data System (ADS)

Medling, Anne M.

2013-03-01

Gas-rich galaxies across cosmic time exhibit one or both of two phenomena: ongoing star formation and an active galactic nucleus indicating current black hole accretion. These two processes are important mechanisms through which galaxies evolve and grow, but their effects are difficult to disentangle. Both will use up some available gas, and both are capable of producing winds strong enough to eject remaining gas from the galaxy. One must look at high spatial resolutions in order to separate the dynamical effects of star formation going on near the nucleus of a galaxy from the black hole growth going on in the nucleus. We present high spatial resolution integral field spectroscopy of fifteen nearby luminous and ultra-luminous infrared galaxies. These systems are extremely bright in the infrared exactly because they host powerful starbursts and active nuclei, which in turn heat the surrounding dust. Our data provide resolved stellar and gaseous kinematics of the central kiloparsec of each of these systems by removing atmospheric blurring with adaptive optics, an observing technique that measures the turbulence in the Earth's atmosphere and then uses a deformable mirror to correct the resulting distortions. Our kinematic maps reveal nuclear disks of gas and stars with radii ˜ a few hundred parsecs surrounding the central black holes. Because the stellar and gas kinematics match well, we conclude that the stars are forming in situ from the gas in the disks. These disks may be the progenitors of kinematically decoupled cores seen in many isolated elliptical galaxies, and may have a significant effect on the merger rate of binary black holes. Additionally, these disks may be used to measure black hole masses which, when combined with host galaxy properties and placed on scaling relations, indicate that black holes grow as or more quickly than their host galaxies during a merger. This suggests that a sudden burst of black hole growth at in the final stages of the merger is not likely to be responsible for shutting off star formation in these systems, unless a time delay is also present.

The impact of the luminance, size and location of LED billboards on drivers' visual performance-Laboratory tests.

PubMed

Zalesinska, Malgorzata

2018-08-01

A proper visual performance by drivers can be ensured by, among else, a correct distribution of luminance in their field of view. At night, when the driver's sight is adapted to low luminance levels, high luminance level objects located near the road may be a source of glare, which is not only a nuisance, but it may also blind the driver. For many years, LED billboards (light-emitting diode billboards) have been installed near roads. Such billboards are usually large, have high luminance and show dynamically changing images. These parameters have a significant impact on the drivers' visual performance and, in turn, on road traffic safety. The study on the impact of the luminance, size and location of LED billboards on the drivers' visual performance was conducted on a volunteer group. Testing the impact of LED billboards on the visual performance of drivers in real-life conditions is very difficult. Therefore, the tests have been conducted in laboratory conditions, using a car driving simulator. The paper describes the testing procedure and tests results. The permissible luminance and areas of LED screens in two locations near the road, which significantly reduce the drivers' visual performance in municipal traffic at night, were determined by conducting an analysis of the results. Recommendations on the permissible luminance and areas of LED billboards were formulated. Copyright © 2018 Elsevier Ltd. All rights reserved.

Radiological image presentation requires consideration of human adaptation characteristics

NASA Astrophysics Data System (ADS)

O'Connell, N. M.; Toomey, R. J.; McEntee, M.; Ryan, J.; Stowe, J.; Adams, A.; Brennan, P. C.

2008-03-01

Visualisation of anatomical or pathological image data is highly dependent on the eye's ability to discriminate between image brightnesses and this is best achieved when these data are presented to the viewer at luminance levels to which the eye is adapted. Current ambient light recommendations are often linked to overall monitor luminance but this relies on specific regions of interest matching overall monitor brightness. The current work investigates the luminances of specific regions of interest within three image-types: postero-anterior (PA) chest; PA wrist; computerised tomography (CT) of the head. Luminance levels were measured within the hilar region and peripheral lung distal radius and supra-ventricular grey matter. For each image type average monitor luminances were calculated with a calibrated photometer at ambient light levels of 0, 100 and 400 lux. Thirty samples of each image-type were employed, resulting in a total of over 6,000 measurements. Results demonstrate that average monitor luminances varied from clinically-significant values by up to a factor of 4, 2 and 6 for chest, wrist and CT head images respectively. Values for the thoracic hilum and wrist were higher and for the peripheral lung and CT brain lower than overall monitor levels. The ambient light level had no impact on the results. The results demonstrate that clinically important radiological information for common radiological examinations is not being presented to the viewer in a way that facilitates optimised visual adaptation and subsequent interpretation. The importance of image-processing algorithms focussing on clinically-significant anatomical regions instead of radiographic projections is highlighted.

Let the sunshine in? The effects of luminance on economic preferences, choice consistency and dominance violations

PubMed Central

Glimcher, Paul W.

2017-01-01

Weather, in particular the intensity and duration of sunshine (luminance), has been shown to significantly affect financial markets. Yet, because of the complexity of market interactions we do not know how human behavior is affected by luminance in a way that could inform theoretical choice models. In this paper, we use data from a field study using an incentive-compatible, decision task conducted daily over a period of two years and from the US Earth System Research Laboratory luminance sensor to investigate the impact of luminance on risk preferences, ambiguity preferences, choice consistency and dominance violations. We find that luminance levels affect all of these. Age and gender influence the strength of some of these effects. PMID:28783734

Meal-stimulated release of methionine-enkephalin into the canine jejunal lumen.

PubMed Central

Money, S R; Petroianu, A; Gintzler, A R; Jaffe, B M

1988-01-01

Application of enkephalins to the luminal surface of the bowel augments intestinal absorption. However, to date, endogenous enkephalins have not been demonstrated within intestinal luminal fluid. To determine whether enkephalins are present in the intestinal lumen, five adult dogs had 25-cm chronic jejunal Thiry-Vella loops constructed. Dogs were studied in the awake, fasted state. Jejunal loops were perfused with isoosmotic, neutral Krebs buffer containing protease inhibitors. After basal sampling, the dogs received a high fat meat meal. Collections were made during the meal and for 60 min postprandially. Luminal met-enkephalin levels were determined by radioimmunoassay and confirmed by HPLC. HPLC separation of luminal samples demonstrated two immunoreactive peaks which co-eluted with pure met-enkephalin and met-enkephalin-sulfoxide. Basal met-enkephalin outputs averaged 52 +/- 13 ng/min. The meal significantly increased mean luminal met-enkephalin output to 137 +/- 71 ng/min. During the initial 20-min postprandial period, output remained elevated (180 +/- 73 ng/min), after which it returned to basal levels. We conclude that met-enkephalin is present in the jejunal lumen, and that luminal release of this opioid is augmented by a meal. Images PMID:3343342

The impact of luminance on tonic and phasic pupillary responses to sustained cognitive load.

PubMed

Peysakhovich, Vsevolod; Vachon, François; Dehais, Frédéric

2017-02-01

Pupillary reactions independent of light conditions have been linked to cognition for a long time. However, the light conditions can impact the cognitive pupillary reaction. Previous studies underlined the impact of luminance on pupillary reaction, but it is still unclear how luminance modulates the sustained and transient components of pupillary reaction - tonic pupil diameter and phasic pupil response. In the present study, we investigated the impact of the luminance on these two components under sustained cognitive load. Fourteen participants performed a novel working memory task combining mathematical computations with a classic n-back task. We studied both tonic pupil diameter and phasic pupil response under low (1-back) and high (2-back) working memory load and two luminance levels (gray and white). We found that the impact of working memory load on the tonic pupil diameter was modulated by the level of luminance, the increase in tonic pupil diameter with the load being larger under lower luminance. In contrast, the smaller phasic pupil response found under high load remained unaffected by luminance. These results showed that luminance impacts the cognitive pupillary reaction - tonic pupil diameter (phasic pupil response) being modulated under sustained (respectively, transient) cognitive load. These findings also support the relationship between the locus-coeruleus system, presumably functioning in two firing modes - tonic and phasic - and the pupil diameter. We suggest that the tonic pupil diameter tracks the tonic activity of the locus-coeruleus while phasic pupil response reflects its phasic activity. Besides, the designed novel cognitive paradigm allows the simultaneous manipulation of sustained and transient components of the cognitive load and is useful for dissociating the effects on the tonic pupil diameter and phasic pupil response. Copyright © 2016 Elsevier B.V. All rights reserved.

Calibrated LCD/TFT stimulus presentation for visual psychophysics in fMRI.

PubMed

Strasburger, H; Wüstenberg, T; Jäncke, L

2002-11-15

Standard projection techniques using liquid crystal (LCD) or thin-film transistor (TFT) technology show drastic distortions in luminance and contrast characteristics across the screen and across grey levels. Common luminance measurement and calibration techniques are not applicable in the vicinity of MRI scanners. With the aid of a fibre optic, we measured screen luminances for the full space of screen position and image grey values and on that basis developed a compensation technique that involves both luminance homogenisation and position-dependent gamma correction. By the technique described, images displayed to a subject in functional MRI can be specified with high precision by a matrix of desired luminance values rather than by local grey value.

Interleukin-10 neutralizing antibody for detection of intestinal luminal levels and as a dietary additive in Eimeria challenged broiler chicks.

PubMed

Arendt, Maria K; Sand, Jordan M; Marcone, Taylor M; Cook, Mark E

2016-02-01

Interleukin-10 (IL-10) mRNA levels are increased within intestinal mucosa after Eimeria infection. IL-10 apical receptor presence on enterocytes suggests IL-10 is secreted into the intestinal lumen. Increased IL-10 has been shown to be central to the pathogenesis of numerous intracellular pathogens; we hypothesize luminal secretion of IL-10 enables Eimeria spp. infection in chickens. This study examines intestine luminal IL-10 levels and performance in broilers challenged with Eimeria when fed an anti-IL-10 antibody. Chicks were fed a diet (1 to 21 d) with control or anti-IL-10 antibody (0.34 g egg yolk antibody powder/Kg diet) with a saline or 10× dose of Advent coccidiosis vaccine on d 3. One chick per pen was euthanized on days 2, 4, 7, 10, 13, 16, and 19 post-challenge, bled, and intestines were collected for luminal fluid IL-10 concentrations. Body weight and feed intake were measured on d 21, and oocyst shedding was assessed on d 7 post-challenge. A significant Eimeria × antibody interaction on d 21 body weight (P < 0.05) showed chicks fed control antibody, but not anti-IL-10, had significant reductions in body weight when challenged with Eimeria spp. Oocyst shedding was increased with Eimeria challenge, but dietary antibody had no effect. Plasma carotenoid levels were reduced in Eimeria challenged chicks 4, 7, 10, and 16 days post-challenge compared to unchallenged chicks. Lack of an Eimeria × antibody interaction showed anti-IL-10 was not protective against Eimeria-induced decreases in plasma carotenoids. Eimeria challenge increased intestine luminal IL-10 on days 4 and 7 post-challenge in the cecum and jejunum, respectively, compared to unchallenged. Dietary anti-IL-10 decreased luminal IL-10 in the ileum on day 2 post-challenge when compared to control antibody fed chicks. No interaction between Eimeria challenge and antibody was observed on intestine luminal contents of IL-10, suggesting anti-IL-10 was ineffective at preventing increased Eimeria-induced luminal IL-10. In conclusion, Eimeria challenge increased intestinal luminal IL-10 and anti-IL-10 was effective at preventing Eimeria-induced decreased body weight, however the mechanism anti-IL-10 antibody protects body weight during Eimeria challenge remains unknown. © 2016 Poultry Science Association Inc.

Human factors studies of control configurations for advanced transport aircraft

NASA Technical Reports Server (NTRS)

Snyder, Harry L.; Monty, Robert W.; Old, Joe

1985-01-01

This research investigated the threshold levels of display luminance contrast which were required to interpret static, achromatic, integrated displays of primary flight information. A four-factor within-subjects design was used to investigate the influences of type of flight variable information, the level of ambient illumination, the type of control input, and the size of the display symbology on the setting of these interpretability thresholds. A three-alternative forced choice paradigm was used in conjunction with the method of adjustments to obtain a measure of the upper limen of display luminance contrast needed to interpret a complex display of primary flight information. The pattern of results and the absolute magnitudes of the luminance contrast settings were found to be in good agreement with previously reported data from psychophysical investigations of display luminance contrast requirements.

A Multi-Purpose, Detector-Based Photometric Calibration System for Luminous Intensity, Illuminance and Luminance

NASA Astrophysics Data System (ADS)

Lam, Brenda H. S.; Yang, Steven S. L.; Chau, Y. C.

2018-02-01

A multi-purpose detector based calibration system for luminous intensity, illuminance and luminance has been developed at the Government of the Hong Kong Special Administrative Region, Standards and Calibration Laboratory (SCL). In this paper, the measurement system and methods are described. The measurement models and contributory uncertainties were validated using the Guide to the Expression of Uncertainty in Measurement (GUM) framework and Supplement 1 to the GUM - Propagation of distributions using a Monte Carlo method in accordance with the JCGM 100:2008 and JCGM 101:2008 at the intended precision level.

Active matrix OLED for rugged HMD and viewfinder applications

NASA Astrophysics Data System (ADS)

Low, Kia; Jones, Susan K.; Prache, Olivier; Fellowes, David A.

2004-09-01

We present characterization of a full-color 852x3x600-pixel, active matrix organic light emitting diode (AMOLED) color microdisplay (eMagin Corporation's SVGA+ display) for environmentally demanding applications. The results show that the AMOLED microdisplay can provide cold-start turn-on and operate at extreme temperature conditions, far in excess of non-emissive displays. Correction factors for gamma response of the AMOLED microdisplay as a function of temperature have been determined to permit consistent luminance and contrast from -40°C to over +80°C. Gamma adjustments are made by a simple temperature compensation adjustment of the reference voltages of the AMOLED. The typical room temperature full-on luminance half-life of the SVGA+ full color display organic light emitting diode (OLED) display at over 3,000 hr at a starting luminance at approx. 100 cd/m2, translates to more than 15,000 hr of continuous full-motion video usage, based on a 25% duty cycle at a typical 50-60 cd/m2 commercial luminance level, or over 60,000 hr half-life in monochrome white usage, or over 100,000 hr luminance half-life in monochrome yellow usage at similar operating conditions. Half life at typical night vision luminance levels would be much longer.

Exploring the multifaceted circumstellar environment of the luminous blue variable HR Carinae

NASA Astrophysics Data System (ADS)

Buemi, C. S.; Trigilio, C.; Leto, P.; Umana, G.; Ingallinera, A.; Cavallaro, F.; Cerrigone, L.; Agliozzo, C.; Bufano, F.; Riggi, S.; Molinari, S.; Schillirò, F.

2017-03-01

We present a multiwavelength study of the Galactic luminous blue variable HR Carinae, based on new high-resolution mid-infrared (IR) and radio images obtained with the Very Large Telescope (VLT) and the Australia Telescope Compact Array (ATCA), which have been complemented by far-infrared Herschel-Photodetector Array Camera and Spectrometer (PACS) observations and ATCA archive data. The Herschel images reveal the large-scale distribution of the dusty emitting nebula, which extends mainly to the north-east direction, up to 70 arcsec from the central star, and is oriented along the direction of the space motion of the star. In the mid-infrared images, the brightness distribution is characterized by two arc-shaped structures, tracing an inner envelope surrounding the central star more closely. At radio wavelengths, the ionized gas emission lies on the opposite side of the cold dust with respect to the position of the star, as if the ionized front were confined by the surrounding medium in the north-south direction. Comparison with previous data indicates significant changes in the radio nebula morphology and in the mass-loss rate from the central star, which has increased from 6.1 × 10-6 M⊙ yr-1 in 1994-1995 to 1.17 × 10-5 M⊙ yr-1 in 2014. We investigate possible scenarios that could have generated the complex circumstellar environment revealed by our multiwavelength data.

Nonlinear mapping of the luminance in dual-layer high dynamic range displays

NASA Astrophysics Data System (ADS)

Guarnieri, Gabriele; Ramponi, Giovanni; Bonfiglio, Silvio; Albani, Luigi

2009-02-01

It has long been known that the human visual system (HVS) has a nonlinear response to luminance. This nonlinearity can be quantified using the concept of just noticeable difference (JND), which represents the minimum amplitude of a specified test pattern an average observer can discern from a uniform background. The JND depends on the background luminance following a threshold versus intensity (TVI) function. It is possible to define a curve which maps physical luminances into a perceptually linearized domain. This mapping can be used to optimize a digital encoding, by minimizing the visibility of quantization noise. It is also commonly used in medical applications to display images adapting to the characteristics of the display device. High dynamic range (HDR) displays, which are beginning to appear on the market, can display luminance levels outside the range in which most standard mapping curves are defined. In particular, dual-layer LCD displays are able to extend the gamut of luminance offered by conventional liquid crystals towards the black region; in such areas suitable and HVS-compliant luminance transformations need to be determined. In this paper we propose a method, which is primarily targeted to the extension of the DICOM curve used in medical imaging, but also has a more general application. The method can be modified in order to compensate for the ambient light, which can be significantly greater than the black level of an HDR display and consequently reduce the visibility of the details in dark areas.

Ribbon synapses compute temporal contrast and encode luminance in retinal rod bipolar cells

PubMed Central

Oesch, Nicholas W.; Diamond, Jeffrey S.

2011-01-01

Contrast is computed throughout the nervous system to encode changing inputs efficiently. The retina encodes luminance and contrast over a wide range of visual conditions and so must adapt its responses to maintain sensitivity and avoid saturation. Here we show how one type of adaptation allows individual synapses to compute contrast and encode luminance in biphasic responses to step changes in light levels. Light-evoked depletion of the readily releasable vesicle pool (RRP) at rod bipolar cell (RBC) ribbon synapses in rat retina limits the dynamic range available to encode transient but not sustained responses, thereby allowing the transient and sustained components of release to compute temporal contrast and encode mean light levels, respectively. A release/replenishment model shows that a single, homogeneous pool of synaptic vesicles is sufficient to generate this behavior and reveals that the dominant mechanism shaping the biphasic contrast/luminance response is the partial depletion of the RRP. PMID:22019730

Impact of physiological hormonal fluctuations on 18F-fluorodeoxyglucose uptake in breast cancer.

PubMed

Miyake, Kanae K; Nakamoto, Yuji; Saji, Shigehira; Sugie, Tomoharu; Kurihara, Kensuke; Kanao, Shotaro; Ikeda, Debra M; Toi, Masakazu; Togashi, Kaori

2018-06-01

Premenopausal physiologic steroid levels change cyclically, in contrast to steady state low levels seen in postmenopausal patients. The purpose of this study was to evaluate whether 18 F-fluorodeoxyglucose ( 18 F-FDG) uptake in breast cancer is influenced by physiological hormonal fluctuations. A total of 160 primary invasive breast cancers from 155 females (54 premenopausal, 101 postmenopausal) who underwent 18 F-FDG positron emission tomography/computed tomography before therapy were retrospectively analyzed. The maximal standardized uptake values (SUVmax) of tumors were compared with menstrual phases and menopausal status according to the following subgroups: 'luminal A-like,' 'luminal B-like,' and 'non-luminal.' Additionally, the effect of estradiol (E2) on 18 F-FDG uptake in breast cancer cells was evaluated in vitro. Among premenopausal patients, SUVmax during the periovulatory-luteal phase was significantly higher than that during the follicular phase in luminal A-like tumors (n = 25, p = 0.004), while it did not differ between the follicular phase and the periovulatory-luteal phase in luminal B-like (n = 24) and non-luminal tumors (n = 7). Multiple regression analysis showed menstrual phase, tumor size, and Ki-67 index are independent predictors for SUVmax in premenopausal luminal A-like tumors. There were no significant differences in SUVmax between pre- and postmenopausal patients in any of the subgroups. In in vitro studies, uptake in estrogen receptor-positive cells was significantly augmented when E2 concentration was increased from 0.01 to ≥ 1 nM. Our data suggest that 18 F-FDG uptake may be impacted by physiological hormonal fluctuations during menstrual cycle in luminal A-like cancers, and that E2 could be partly responsible for these events.

Extracting and shaping the light of OLED devices

NASA Astrophysics Data System (ADS)

Riedel, Daniel; Dlugosch, Julian; Wehlus, Thomas; Brabec, Christoph

2015-09-01

Before the market entry of organic light emitting diodes (OLEDs) into the field of general illumination can occur, limitations in lifetime, luminous efficacy and cost must be overcome. Additional requirements for OLEDs used for general illumination may be imposed by workplace glare reduction requirements, which demand limited luminance for high viewing angles. These requirements contrast with the typical lambertian emission characteristics of OLEDs, which result in the same luminance levels for all emission angles. As a consequence, without additional measures glare reduction could limit the maximum possible luminance of lambertian OLEDs to relatively low levels. However, high luminance levels are still desirable in order to obtain high light output. We are presenting solutions to overcome this dilemma. Therefore this work is focused on light-shaping structures for OLEDs with an internal light extraction layer. Simulations of beam-shaping structures and shapes are presented, followed by experimental measurements to verify the simulations of the most promising structures. An investigation of the loss channels has been carried out and the overall optical system efficiency was evaluated for all structures. The most promising light shaping structures achieve system efficiencies up to 80%. Finally, a general illumination application scenario has been simulated. The number of OLEDs needed to illuminate an office room has been deduced from this scenario. By using light-shaping structures for OLEDs, the number of OLEDs needed to reach the mandatory illuminance level for a workplace environment can be reduced to one third compared to lambertian OLEDs.

Inhibitors of acid secretion can benefit gastric wound repair independent of luminal pH effects on the site of damage

PubMed Central

Demitrack, Elise S; Aihara, Eitaro; Kenny, Susan; Varro, Andrea; Montrose, Marshall H

2012-01-01

Background and aims The authors’ goal was to measure pH at the gastric surface (pHo) to understand how acid secretion affects the repair of microscopic injury to the gastric epithelium. Methods Microscopic gastric damage was induced by laser light, during confocal/two-photon imaging of pH-sensitive dyes (Cl-NERF, BCECF) that were superfused over the mucosal surface of the exposed gastric corpus of anaesthetised mice. The progression of repair was measured in parallel with pHo. Experimental conditions included varying pH of luminal superfusates, and using omeprazole (60 mg/kg ip) or famotidine (30 mg/kg ip) to inhibit acid secretion. Results Similar rates of epithelial repair and resting pHo values (~pH 4) were reported in the presence of luminal pH 3 or pH 5. Epithelial repair was unreliable at luminal pH 2 and pHo was lower (2.5±0.2, P <0.05 vs pH 3). Epithelial repair was slower at luminal pH 7 and pHo was higher (6.4±0.1, P<0.001). In all conditions, pHo increased adjacent to damage. At luminal pH 3 or pH 7, omeprazole reduced maximal damage size and accelerated epithelial repair, although only at pH 3 did omeprazole further increase surface pH above the level caused by imposed damage. At luminal pH 7, famotidine also reduced maximal damage size and accelerated epithelial repair. Neither famotidine nor omeprazole raised plasma gastrin levels during the time course of the experiments. Conclusions Epithelial repair in vivo is affected by luminal pH variation, but the beneficial effects of acutely blocking acid secretion extend beyond simply raising luminal and/or surface pH. PMID:21997560

Extensive Transcriptomic and Genomic Analysis Provides New Insights about Luminal Breast Cancers

PubMed Central

Tishchenko, Inna; Milioli, Heloisa Helena; Riveros, Carlos; Moscato, Pablo

2016-01-01

Despite constituting approximately two thirds of all breast cancers, the luminal A and B tumours are poorly classified at both clinical and molecular levels. There are contradictory reports on the nature of these subtypes: some define them as intrinsic entities, others as a continuum. With the aim of addressing these uncertainties and identifying molecular signatures of patients at risk, we conducted a comprehensive transcriptomic and genomic analysis of 2,425 luminal breast cancer samples. Our results indicate that the separation between the molecular luminal A and B subtypes—per definition—is not associated with intrinsic characteristics evident in the differentiation between other subtypes. Moreover, t-SNE and MST-kNN clustering approaches based on 10,000 probes, associated with luminal tumour initiation and/or development, revealed the close connections between luminal A and B tumours, with no evidence of a clear boundary between them. Thus, we considered all luminal tumours as a single heterogeneous group for analysis purposes. We first stratified luminal tumours into two distinct groups by their HER2 gene cluster co-expression: HER2-amplified luminal and ordinary-luminal. The former group is associated with distinct transcriptomic and genomic profiles, and poor prognosis; it comprises approximately 8% of all luminal cases. For the remaining ordinary-luminal tumours we further identified the molecular signature correlated with disease outcomes, exhibiting an approximately continuous gene expression range from low to high risk. Thus, we employed four virtual quantiles to segregate the groups of patients. The clinico-pathological characteristics and ratios of genomic aberrations are concordant with the variations in gene expression profiles, hinting at a progressive staging. The comparison with the current separation into luminal A and B subtypes revealed a substantially improved survival stratification. Concluding, we suggest a review of the definition of luminal A and B subtypes. A proposition for a revisited delineation is provided in this study. PMID:27341628

Binocular combination of luminance profiles

PubMed Central

Ding, Jian; Levi, Dennis M.

2017-01-01

We develop and test a new two-dimensional model for binocular combination of the two eyes' luminance profiles. For first-order stimuli, the model assumes that one eye's luminance profile first goes through a luminance compressor, receives gain-control and gain-enhancement from the other eye, and then linearly combines the other eye's output profile. For second-order stimuli, rectification is added in the signal path of the model before the binocular combination site. Both the total contrast and luminance energies, weighted sums over both the space and spatial-frequency domains, were used in the interocular gain-control, while only the total contrast energy was used in the interocular gain-enhancement. To challenge the model, we performed a binocular brightness matching experiment over a large range of background and target luminances. The target stimulus was a dichoptic disc with a sharp edge that has an increment or decrement luminance from its background. The disk's interocular luminance ratio varied from trial to trial. To refine the model we tested three luminance compressors, five nested binocular combination models (including the Ding–Sperling and the DSKL models), and examined the presence or absence of total luminance energy in the model. We found that (1) installing a luminance compressor, either a logarithmic luminance function or luminance gain-control, (2) including both contrast and luminance energies, and (3) adding interocular gain-enhancement (the DSKL model) to a combined model significantly improved its performance. The combined model provides a systematic account of binocular luminance summation over a large range of luminance input levels. It gives a unified explanation of Fechner's paradox observed on a dark background, and a winner-take-all phenomenon observed on a light background. To further test the model, we conducted two additional experiments: luminance summation of discs with asymmetric contour information (Experiment 2), similar to Levelt (1965) and binocular combination of second-order contrast-modulated gratings (Experiment 3). We used the model obtained in Experiment 1 to predict the results of Experiments 2 and 3 and the results of our previous studies. Model simulations further refined the contrast space weight and contrast sensitivity functions that are installed in the model, and provide a reasonable account for rebalancing of imbalanced binocular vision by reducing the mean luminance in the dominant eye. PMID:29098293

Circumstellar disks of the most vigorously accreting young stars.

PubMed

Liu, Hauyu Baobab; Takami, Michihiro; Kudo, Tomoyuki; Hashimoto, Jun; Dong, Ruobing; Vorobyov, Eduard I; Pyo, Tae-Soo; Fukagawa, Misato; Tamura, Motohide; Henning, Thomas; Dunham, Michael M; Karr, Jennifer L; Kusakabe, Nobuhiko; Tsuribe, Toru

2016-02-01

Stars may not accumulate their mass steadily, as was previously thought, but in a series of violent events manifesting themselves as sharp stellar brightening. These events can be caused by fragmentation due to gravitational instabilities in massive gaseous disks surrounding young stars, followed by migration of dense gaseous clumps onto the star. Our high-resolution near-infrared imaging has verified the presence of the key associated features, large-scale arms and arcs surrounding four young stellar objects undergoing luminous outbursts. Our hydrodynamics simulations and radiative transfer models show that these observed structures can indeed be explained by strong gravitational instabilities occurring at the beginning of the disk formation phase. The effect of those tempestuous episodes of disk evolution on star and planet formation remains to be understood.

Circumstellar disks of the most vigorously accreting young stars

PubMed Central

Liu, Hauyu Baobab; Takami, Michihiro; Kudo, Tomoyuki; Hashimoto, Jun; Dong, Ruobing; Vorobyov, Eduard I.; Pyo, Tae-Soo; Fukagawa, Misato; Tamura, Motohide; Henning, Thomas; Dunham, Michael M.; Karr, Jennifer L.; Kusakabe, Nobuhiko; Tsuribe, Toru

2016-01-01

Stars may not accumulate their mass steadily, as was previously thought, but in a series of violent events manifesting themselves as sharp stellar brightening. These events can be caused by fragmentation due to gravitational instabilities in massive gaseous disks surrounding young stars, followed by migration of dense gaseous clumps onto the star. Our high-resolution near-infrared imaging has verified the presence of the key associated features, large-scale arms and arcs surrounding four young stellar objects undergoing luminous outbursts. Our hydrodynamics simulations and radiative transfer models show that these observed structures can indeed be explained by strong gravitational instabilities occurring at the beginning of the disk formation phase. The effect of those tempestuous episodes of disk evolution on star and planet formation remains to be understood. PMID:26989772

Microbes vs. chemistry in the origin of the anaerobic gut lumen.

PubMed

Friedman, Elliot S; Bittinger, Kyle; Esipova, Tatiana V; Hou, Likai; Chau, Lillian; Jiang, Jack; Mesaros, Clementina; Lund, Peder J; Liang, Xue; FitzGerald, Garret A; Goulian, Mark; Lee, Daeyeon; Garcia, Benjamin A; Blair, Ian A; Vinogradov, Sergei A; Wu, Gary D

2018-04-17

The succession from aerobic and facultative anaerobic bacteria to obligate anaerobes in the infant gut along with the differences between the compositions of the mucosally adherent vs. luminal microbiota suggests that the gut microbes consume oxygen, which diffuses into the lumen from the intestinal tissue, maintaining the lumen in a deeply anaerobic state. Remarkably, measurements of luminal oxygen levels show nearly identical pO 2 (partial pressure of oxygen) profiles in conventional and germ-free mice, pointing to the existence of oxygen consumption mechanisms other than microbial respiration. In vitro experiments confirmed that the luminal contents of germ-free mice are able to chemically consume oxygen (e.g., via lipid oxidation reactions), although at rates significantly lower than those observed in the case of conventionally housed mice. For conventional mice, we also show that the taxonomic composition of the gut microbiota adherent to the gut mucosa and in the lumen throughout the length of the gut correlates with oxygen levels. At the same time, an increase in the biomass of the gut microbiota provides an explanation for the reduction of luminal oxygen in the distal vs. proximal gut. These results demonstrate how oxygen from the mammalian host is used by the gut microbiota, while both the microbes and the oxidative chemical reactions regulate luminal oxygen levels, shaping the composition of the microbial community throughout different regions of the gut.

The ISO View of Palomar-Green Quasars

NASA Technical Reports Server (NTRS)

Haas, M.; Klaas, U.; Mueller, S. A. H.; Bertoldi, F.; Camenzind, M.; Chini, R.; Krause, O.; Lemke, D.; Meisenheimer; Richards, P. J.

2003-01-01

Mining the ISO data archive we provide the complete ISO view of PG quasars containing 64 infrared spectral energy distributions between 5 and 200 mu m. About half of the sample was supplemented by MAMBO and SCUBA (sub-)millimeter data. Since the PG quasars were selected optically, the high infrared detection rate of more than 80% suggests that every quasar possesses luminous to hyper-luminous dust emission with dust masses comparable to Seyferts and ultra-luminous IR galaxies (ULIRGs). The gas to-dust mass ratio (of those sources where CO measurements are available in the literature) is consistent with the galactic value providing further evidence for the thermal nature of the IR emission of radio quiet quasars. The SEDs represent templates of unprecedented detail and sensitivity. We suggest that the diversity of the SEDs reflects largely the evolution of the dust distribution, and we propose a classification of the SED shapes as well as an evolutionary scheme in which this variety can be understood. During the evolution the surrounding dust redistributes, settling more and more into a torus/disk like configuration, while the SEDs show an initial FIR bump, then an increasing MIR emission and a steeper near- to mid-infrared slope, both of which finally also decrease. Regarding cosmic evolution, our hyper-luminous quasars in the "local" universe at z=l do not show the hyper-luminous (LFIR >? 10(exp 13) L(sub sun)) starburst activity inferred for z=4 quasars detected in several (sub-)millimeter surveys. In view of several caveats this difference should be established further, but it already suggests that in the early dense universe stronger merger events led to more powerful starbursts accompanying the quasar phenomenon, while at later cosmic epochs any coeval starbursts obviously do not reach that high power and are outshone by the AGN. Additional information is included in the original extended abstract.

Theoretical design and evaluation of endoluminal ultrasound applicators for thermal therapy of pancreatic cancer under image guidance

NASA Astrophysics Data System (ADS)

Adams, Matthew; Scott, Serena; Salgaonkar, Vasant; Sommer, Graham; Diederich, Chris

2017-03-01

An image-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. By considering a directional transducer array of planar, tubular, or curvilinear transducers, this design offers the potential for fast volumetric therapy and 3D spatial control over the energy deposition profile. Treatment of pancreatic tumor tissue would be performed in a minimally invasive fashion with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal wall would be achieved with a water-cooled balloon surrounding the transducers. A theoretical evaluation of this design was performed by developing a 3D acoustic and bioheat transfer model, with temperature and thermal dose solutions obtained using a FEM solver (COMSOL Multiphysics). Parametric studies were performed on a generalized anatomical model of the pancreas, tumor, and adjacent luminal wall to determine preferred transducer configurations and frequencies for maximizing lesion volume and penetration while sparing the luminal wall. Patient-specific models of pancreatic tumors were generated from CT studies and used to assess the feasibility of performing thermal ablation or hyperthermia on small (˜2 cm diameter) pancreatic head tumors with an endoluminal applicator positioned within the duodenum. Simulation results indicate lower transducer operating frequencies (1-3 MHz) are necessary to mitigate damage to the luminal wall, and a tradeoff between penetration depth and lesion volume emerges as the degree of focusing increases. For patient-specific ablation modeling of tumors within 30 mm of the luminal wall, approximately 95% of the volume could be ablated within 15 min using a planar or lightly focused transducer configuration without duodenal damage. Over 90% of the volume could be elevated above 40°C at steady state for hyperthermia applications (e.g., radiation sensitization, drug delivery) using a tubular transducer. For tumors extending deeper into the pancreas (˜35 mm), strongly focused curvilinear transducers could ablate over 80% of the tumor volume within 15 min while minimizing damage to nearby sensitive structures.

Luminous fabric devices for wearable low-level light therapy

PubMed Central

Shen, Jing; Chui, Chunghin; Tao, Xiaoming

2013-01-01

In this paper, a flexible luminous fabric device was developed and investigated for wearable three-dimensionally fitted low-level light therapy. The fabric device exhibited excellent optical and thermal properties. Its optical power density and operating temperature were stable during usage for 10 hours. In vitro experiments demonstrated a significant increase in collagen production in human fibroblast irradiated by the fabric device, compared with the fibroblast without light irradiation. A series of tests were conducted for the safety of the fabric for human skin contact according to ISO standard ISO 10993-1:2003. The results showed that there was no potential hazard when the luminous fabrics were in direct contact with human skin. PMID:24409391

Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices.

PubMed

Livingstone, I A T; Tarbert, C M; Giardini, M E; Bastawrous, A; Middleton, D; Hamilton, R

2016-01-01

Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m2) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%). Two charts were operating beyond manufacturer's recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out-performed ETDRS charts in terms of photometric compliance with high contrast acuity standards.

Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices

PubMed Central

Livingstone, I. A. T.; Tarbert, C. M.; Giardini, M. E.; Bastawrous, A.; Middleton, D.; Hamilton, R.

2016-01-01

Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m2) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%). Two charts were operating beyond manufacturer’s recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out-performed ETDRS charts in terms of photometric compliance with high contrast acuity standards. PMID:27002333

The Nature of the Energy Source in LINER's

NASA Technical Reports Server (NTRS)

Colina, L.; Koratkar, Anuradha

1996-01-01

LINER's (low-ionization nuclear emission-line regions) are found in about 30% of all bright galaxies, including luminous infrared galaxies. They form a heterogeneous class powered by a variety of ionizing mechanisms such as low-luminosity AGNs (active galactic nuclei), starbursts, shocks, or any combination of these. In early-type spirals, LINER's are powered by a low-luminosity AGN, or by an AGN surrounded by circumnuclear star-forming regions. In luminous infrared galaxies, LINER's are powered by starbursts with associated wind-related extended shocks, and an AGN may play a minor role, if any. LINER's in some FR I radio galaxies show strong evidence for the presence of a massive central black hole, and there are indications for the existence of shocks in the nuclear disks of these galaxies. Yet, the dominant ionizing mechanism for LINER's in radio-quiet ellipticals and FR I host galaxies is still unclear. Multifrequency high spatial resolution imaging and spectroscopy are essential to discriminate among the different ionizing mechanisms present in LINER's.

MicroRNA-139 suppresses proliferation in luminal type breast cancer cells by targeting Topoisomerase II alpha

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hua, Wei; State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, 710032 Xi'an; Sa, Ke-Di

The classification of molecular subtypes of breast cancer improves the prognostic accuracy and therapeutic benefits in clinic. However, because of the complexity of breast cancer, more biomarkers and functional molecules need to be explored. Here, analyzing the data in a huge cohort of breast cancer patients, we found that Topoisomerase II alpha (TOP2a), an important target of chemotherapy is a biomarker for prognosis in luminal type breast cancer patients, but not in basal like or HER2 positive breast cancer patients. We identified that miR-139, a previous reported anti-metastatic microRNA targets 3’-untranslated region (3′UTR) of TOP2a mRNA. Further more, we revealedmore » that the forced expression of miR-139 reduces the TOP2a expression at both mRNA and protein levels. And our functional experiments showed that the ectopic expression of miR-139 remarkably inhibits proliferation in luminal type breast cancer cells, while exogenous TOP2a expression could rescue inhibition of cell proliferation mediated by miR-139. Collectively, our present study demonstrates the miR-139-TOP2a regulatory axis is important for proliferation in luminal type breast cancer cells. This functional link may help us to further understand the specificity of subtypes of breast cancer and optimize the strategy of cancer treatment. - Highlights: • High levels of TOP2a expression are closely associated with poor prognosis in luminal type breast cancer patients. • TOP2a is a novel target of miR-139. • Overexpression of miR-139 inhibits proliferation in luminal type breast cancer cells. • TOP2a is essential for miR-139-induced growth arrest in luminal type breast cancer cells.« less

A global simulation approach to optics, lighting, rendering, and human perception for the improvement of safety in automobiles

NASA Astrophysics Data System (ADS)

Delacour, Jacques; Fournier, Laurent; Menu, Jean-Pierre

2005-02-01

In order to provide optimum comfort and safety conditions, information must be seen as clearly as possible by the driver and in all lighting conditions, by day and by night. Therefore, it is becoming fundamental to anticipate in order to predict what the driver will see in a vehicle, in various configurations of scene and observation conditions, so as to optimize the lighting, the ergonomics of the interfaces and the choice of surrounding materials which can be a source of reflection. This information and choices which will depend on it, make it necessary to call upon simulation techniques capable of modeling, globally and simultaneously, the entire light phenomena: surrounding lighting, display technologies, the inside lighting, taking into consideration the multiple reflections caused by the reflection of this light inside the vehicle. This has been the object of an important development, which results in the solution SPEOS Visual Ergonomics, led by company OPTIS. A unique human vision model was developed in collaboration with worldwide specialists in visual perception to transform spectral luminance information into perceived visual information. This model, based on physiological aspects, takes into account the response of the eye to light levels, to color, to contrast, and to ambient lighting, as well as to rapid changes in surrounding luminosity, in accordance with the response of the retina. This unique tool, and information now accessible, enable ergonomists and designers of on board systems to improve the conditions of global visibility, and in so doing the global perception of the environment that the driver will have.

Alkaline phosphatases contribute to uterine receptivity, implantation, decidualization and defense against bacterial endotoxin in hamsters

PubMed Central

Lei, Wei; Nguyen, Heidi; Brown, Naoko; Ni, Hua; Kiffer-Moreira, Tina; Reese, Jeff; Millán, José Luis; Paria, Bibhash C.

2013-01-01

Alkaline phosphatase (AP) activity has been demonstrated in the uterus of several species, but its importance in the uterus, in general and during pregnancy, is yet to be revealed. In this study, we focused on identifying AP isozyme types, and their hormonal regulation, cell-type and event-specific expression and possible functions in the hamster uterus during the cycle and early pregnancy. Our RT-PCR and in situ hybridization studies demonstrated that among the known Akp2, Akp3, Akp5 and Akp6 murine AP isozyme genes, hamster uteri express only Akp2 and Akp6; and both genes are co-expressed in luminal epithelial cells. Studies in cyclic and ovariectomized hamsters established that while progesterone is the major uterine Akp2 inducer, both progesterone and estrogen are strong Akp6 regulators. Studies in preimplantation uteri showed induction of both genes and the activity of their encoded isozymes in luminal epithelial cells during uterine receptivity. However, at the beginning of implantation, Akp2 showed reduced expression in luminal epithelial cells surrounding the implanted embryo. In contrast, expression of Akp6 and its isozyme was maintained in luminal epithelial cells adjacent to, but not away from, the implanted embryo. Following implantation, stromal transformation to decidua was associated with induced expressions of only Akp2 and its isozyme. We next demonstrated that uterine APs dephosphorylate and detoxify endotoxin lipopolysaccharide at their sites of production and activity. Taken together, our findings suggest that uterine APs contribute to uterine receptivity, implantation, and decidualization in addition to their role in protection of the uterus and pregnancy against bacterial infection. PMID:23929901

A neural model of border-ownership from kinetic occlusion.

PubMed

Layton, Oliver W; Yazdanbakhsh, Arash

2015-01-01

Camouflaged animals that have very similar textures to their surroundings are difficult to detect when stationary. However, when an animal moves, humans readily see a figure at a different depth than the background. How do humans perceive a figure breaking camouflage, even though the texture of the figure and its background may be statistically identical in luminance? We present a model that demonstrates how the primate visual system performs figure-ground segregation in extreme cases of breaking camouflage based on motion alone. Border-ownership signals develop as an emergent property in model V2 units whose receptive fields are nearby kinetically defined borders that separate the figure and background. Model simulations support border-ownership as a general mechanism by which the visual system performs figure-ground segregation, despite whether figure-ground boundaries are defined by luminance or motion contrast. The gradient of motion- and luminance-related border-ownership signals explains the perceived depth ordering of the foreground and background surfaces. Our model predicts that V2 neurons, which are sensitive to kinetic edges, are selective to border-ownership (magnocellular B cells). A distinct population of model V2 neurons is selective to border-ownership in figures defined by luminance contrast (parvocellular B cells). B cells in model V2 receive feedback from neurons in V4 and MT with larger receptive fields to bias border-ownership signals toward the figure. We predict that neurons in V4 and MT sensitive to kinetically defined figures play a crucial role in determining whether the foreground surface accretes, deletes, or produces a shearing motion with respect to the background. Copyright © 2014 Elsevier Ltd. All rights reserved.

The nature of the ionised nebula surrounding the red supergiant W26

NASA Astrophysics Data System (ADS)

Wesson, Roger

2015-08-01

The red supergiant W26 in the massive star cluster Westerlund 1 is surrounded by a compact ionised nebula. This is unique among RSGs, and the excitation mechanism of the nebula is not yet known - it may be ionised by an unseen compact companion, or by a nearby blue supergiant. We present new observations of the nebula: high resolution spatially resolved spectra taken with FLAMES at the VLT show that the nebula is a ring, with velocities consistent with that expected for red supergiant ejecta, and ruling out the possibility of a Luminous Blue Variable-type eruption preceding the RSG phase as the origin of the nebula. A triangular patch of nebulosity outside the ring appears to be associated with W26, and may be material stripped from the expanding ring by the cumulative cluster wind and radiation field.

Viewing boxes: a survey in diagnostic radiology departments of Moroccan hospitals.

PubMed

Bentayeb, F; Nfaoiu, K; Basraoui, O; Azevedo, A C P

2010-10-01

This work consists on a survey of the performance of viewing boxes installed in diagnostic radiology departments and included several aspects: checking the illuminance of the diagnostic rooms where the viewing boxes are located as well as the viewing boxes luminance levels and homogeneity. Seven hospitals took part in the survey, being three in the city of Casablanca and four in Rabat. A total of 136 viewing boxes and 18 diagnostic rooms have been checked. It was found that one diagnostic room works under normal conditions and that 80% of the viewing boxes present luminance levels below the international recommendations and the homogeneity is inadequate in 85%. Some simple and cheap initiatives can be performed in these departments to increase luminance and improve homogeneity levels such as cleaning and bulbs replacement. Copyright © 2009 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Daylight levels during the solar eclipse of 11 August 1999

NASA Astrophysics Data System (ADS)

Darula, S.; Kambezidis, H. D.; Kittler, R.

Solar eclipses are unique phenomena not only for astronomical and space observations but also for terrestrial; they create unique conditions of sunbeam blockage which cause not only the reduction of direct sunlight but also the dimming of skylight from the whole sky vault. Very favorable conditions were met during the recent August 1999 solar eclipse in Athens, Greece and Bratislava, Slovakia. General class daylight stations operate within the International Daylight Measurements Program in the two cities. One-minute data of global/diffuse illuminance and zenith luminance from those stations have been used to provide information about their levels and the daylight reduction rate during the eclipse. An approximate formula for the estimation of sunlight and skylight illuminance levels as well as zenith luminance using relative luminance sky patterns is also presented in this work. To achieve this, recently developed sky standards together with their parameterizations are utilized.

Purely temporal figure-ground segregation.

PubMed

Kandil, F I; Fahle, M

2001-05-01

Visual figure-ground segregation is achieved by exploiting differences in features such as luminance, colour, motion or presentation time between a figure and its surround. Here we determine the shortest delay times required for figure-ground segregation based on purely temporal features. Previous studies usually employed stimulus onset asynchronies between figure- and ground-containing possible artefacts based on apparent motion cues or on luminance differences. Our stimuli systematically avoid these artefacts by constantly showing 20 x 20 'colons' that flip by 90 degrees around their midpoints at constant time intervals. Colons constituting the background flip in-phase whereas those constituting the target flip with a phase delay. We tested the impact of frequency modulation and phase reduction on target detection. Younger subjects performed well above chance even at temporal delays as short as 13 ms, whilst older subjects required up to three times longer delays in some conditions. Figure-ground segregation can rely on purely temporal delays down to around 10 ms even in the absence of luminance and motion artefacts, indicating a temporal precision of cortical information processing almost an order of magnitude lower than the one required for some models of feature binding in the visual cortex [e.g. Singer, W. (1999), Curr. Opin. Neurobiol., 9, 189-194]. Hence, in our experiment, observers are unable to use temporal stimulus features with the precision required for these models.

The Search for New Luminous Blue Variable Stars: Near-Infrared Spectroscopy of Stars With 24 micron Shells

NASA Astrophysics Data System (ADS)

Stringfellow, Guy; Gvaramadze, Vasilii

2010-02-01

Luminous Blue Variable (LBV) stars represent an extremely rare class of very luminous and massive stars. Only about a dozen confirmed Galactic LBV stars are known to date, which precludes us from determining a solid evolutionary connection between LBV and other intermediate (e.g. Ofpe/WN9, WNL) phases in the life of very massive stars. The known LBV stars each have their own unique properties, so new discoveries add insight into the properties and evolutionary status of LBVs and massive stars; even one new discovery of objects of this type could provide break-through results in the understanding of the intermediate stages of massive star evolution. We have culled a prime sample of possible LBV candidates from the Spitzer 24 (micron) archival data. All have circumstellar nebulae, rings, and shells (typical of LBVs and related stars) surrounding reddened central stars. Spectroscopic followup of about two dozen optically visible central stars associated with the shells from this sample showed that they are either candidate LBVs, late WN-type Wolf-Rayet stars or blue supergiants. We propose infrared spectroscopic observations of the central stars for a large fraction (23 stars) of our northern sample to determine their nature and discover additional LBV candidates. These stars have no plausible optical counterparts, so infrared spectra are needed. This program requires two nights of Hale time using TripleSpec.

Influence of high ambient illuminance and display luminance on readability and subjective preference

NASA Astrophysics Data System (ADS)

De Moor, Katrien; Andrén, Börje; Guo, Yi; Brunnström, Kjell; Wang, Kun; Drott, Anton; Hermann, David S.

2015-03-01

Many devices, such as tablets, smartphones, notebooks, fixed and portable navigation systems are used on a (nearly) daily basis, both in in- and outdoor environments. It is often argued that contextual factors, such as the ambient illuminance in relation to characteristics of the display (e.g., surface treatment, screen reflectance, display luminance …) may have a strong influence on the use of such devices and corresponding user experiences. However, the current understanding of these influence factors is still rather limited. In this work, we therefore focus in particular on the impact of lighting and display luminance on readability, visual performance, subjective experience and preference. A controlled lab study (N=18) with a within-subjects design was performed to evaluate two car displays (one glossy and one matte display) in conditions that simulate bright outdoor lighting conditions. Four ambient luminance levels and three display luminance settings were combined into 7 experimental conditions. More concretely, we investigated for each display: (1) whether and how readability and visual performance varied with the different combinations of ambient luminance and display luminance and (2) whether and how they influenced the subjective experience (through self-reported valence, annoyance, visual fatigue) and preference. The results indicate a limited, yet negative influence of increased ambient luminance and reduced contrast on visual performance and readability for both displays. Similarly, we found that the self-reported valence decreases and annoyance and visual fatigue increase as the contrast ratio decreases and ambient luminance increases. Overall, the impact is clearer for the matte display than for the glossy display.

Metabolomics Analysis of Hormone-Responsive and Triple-Negative Breast Cancer Cell Responses to Paclitaxel Identify Key Metabolic Differences.

PubMed

Stewart, Delisha A; Winnike, Jason H; McRitchie, Susan L; Clark, Robert F; Pathmasiri, Wimal W; Sumner, Susan J

2016-09-02

To date, no targeted therapies are available to treat triple negative breast cancer (TNBC), while other breast cancer subtypes are responsive to current therapeutic treatment. Metabolomics was conducted to reveal differences in two hormone receptor-negative TNBC cell lines and two hormone receptor-positive Luminal A cell lines. Studies were conducted in the presence and absence of paclitaxel (Taxol). TNBC cell lines had higher levels of amino acids, branched-chain amino acids, nucleotides, and nucleotide sugars and lower levels of proliferation-related metabolites like choline compared with Luminal A cell lines. In the presence of paclitaxel, each cell line showed unique metabolic responses, with some similarities by type. For example, in the Luminal A cell lines, levels of lactate and creatine decreased while certain choline metabolites and myo-inositol increased with paclitaxel. In the TNBC cell lines levels of glutamine, glutamate, and glutathione increased, whereas lysine, proline, and valine decreased in the presence of drug. Profiling secreted inflammatory cytokines in the conditioned media demonstrated a greater response to paclitaxel in the hormone-positive Luminal cells compared with a secretion profile that suggested greater drug resistance in the TNBC cells. The most significant differences distinguishing the cell types based on pathway enrichment analyses were related to amino acid, lipid and carbohydrate metabolism pathways, whereas several biological pathways were differentiated between the cell lines following treatment.

ELF5 Drives Lung Metastasis in Luminal Breast Cancer through Recruitment of Gr1+ CD11b+ Myeloid-Derived Suppressor Cells.

PubMed

Gallego-Ortega, David; Ledger, Anita; Roden, Daniel L; Law, Andrew M K; Magenau, Astrid; Kikhtyak, Zoya; Cho, Christina; Allerdice, Stephanie L; Lee, Heather J; Valdes-Mora, Fatima; Herrmann, David; Salomon, Robert; Young, Adelaide I J; Lee, Brian Y; Sergio, C Marcelo; Kaplan, Warren; Piggin, Catherine; Conway, James R W; Rabinovich, Brian; Millar, Ewan K A; Oakes, Samantha R; Chtanova, Tatyana; Swarbrick, Alexander; Naylor, Matthew J; O'Toole, Sandra; Green, Andrew R; Timpson, Paul; Gee, Julia M W; Ellis, Ian O; Clark, Susan J; Ormandy, Christopher J

2015-12-01

During pregnancy, the ETS transcription factor ELF5 establishes the milk-secreting alveolar cell lineage by driving a cell fate decision of the mammary luminal progenitor cell. In breast cancer, ELF5 is a key transcriptional determinant of tumor subtype and has been implicated in the development of insensitivity to anti-estrogen therapy. In the mouse mammary tumor virus-Polyoma Middle T (MMTV-PyMT) model of luminal breast cancer, induction of ELF5 levels increased leukocyte infiltration, angiogenesis, and blood vessel permeability in primary tumors and greatly increased the size and number of lung metastasis. Myeloid-derived suppressor cells, a group of immature neutrophils recently identified as mediators of vasculogenesis and metastasis, were recruited to the tumor in response to ELF5. Depletion of these cells using specific Ly6G antibodies prevented ELF5 from driving vasculogenesis and metastasis. Expression signatures in luminal A breast cancers indicated that increased myeloid cell invasion and inflammation were correlated with ELF5 expression, and increased ELF5 immunohistochemical staining predicted much shorter metastasis-free and overall survival of luminal A patients, defining a group who experienced unexpectedly early disease progression. Thus, in the MMTV-PyMT mouse mammary model, increased ELF5 levels drive metastasis by co-opting the innate immune system. As ELF5 has been previously implicated in the development of antiestrogen resistance, this finding implicates ELF5 as a defining factor in the acquisition of the key aspects of the lethal phenotype in luminal A breast cancer.

ELF5 Drives Lung Metastasis in Luminal Breast Cancer through Recruitment of Gr1+ CD11b+ Myeloid-Derived Suppressor Cells

PubMed Central

Gallego-Ortega, David; Ledger, Anita; Roden, Daniel L.; Law, Andrew M. K.; Magenau, Astrid; Kikhtyak, Zoya; Cho, Christina; Allerdice, Stephanie L.; Lee, Heather J.; Valdes-Mora, Fatima; Herrmann, David; Salomon, Robert; Young, Adelaide I. J.; Lee, Brian Y.; Sergio, C. Marcelo; Kaplan, Warren; Piggin, Catherine; Conway, James R. W.; Rabinovich, Brian; Millar, Ewan K. A.; Oakes, Samantha R.; Chtanova, Tatyana; Swarbrick, Alexander; Naylor, Matthew J.; O’Toole, Sandra; Green, Andrew R.; Timpson, Paul; Gee, Julia M. W.; Ellis, Ian O.; Clark, Susan J.; Ormandy, Christopher J.

2015-01-01

During pregnancy, the ETS transcription factor ELF5 establishes the milk-secreting alveolar cell lineage by driving a cell fate decision of the mammary luminal progenitor cell. In breast cancer, ELF5 is a key transcriptional determinant of tumor subtype and has been implicated in the development of insensitivity to anti-estrogen therapy. In the mouse mammary tumor virus-Polyoma Middle T (MMTV-PyMT) model of luminal breast cancer, induction of ELF5 levels increased leukocyte infiltration, angiogenesis, and blood vessel permeability in primary tumors and greatly increased the size and number of lung metastasis. Myeloid-derived suppressor cells, a group of immature neutrophils recently identified as mediators of vasculogenesis and metastasis, were recruited to the tumor in response to ELF5. Depletion of these cells using specific Ly6G antibodies prevented ELF5 from driving vasculogenesis and metastasis. Expression signatures in luminal A breast cancers indicated that increased myeloid cell invasion and inflammation were correlated with ELF5 expression, and increased ELF5 immunohistochemical staining predicted much shorter metastasis–free and overall survival of luminal A patients, defining a group who experienced unexpectedly early disease progression. Thus, in the MMTV-PyMT mouse mammary model, increased ELF5 levels drive metastasis by co-opting the innate immune system. As ELF5 has been previously implicated in the development of antiestrogen resistance, this finding implicates ELF5 as a defining factor in the acquisition of the key aspects of the lethal phenotype in luminal A breast cancer. PMID:26717410

Strong alkalinization in the anterior midgut of larval yellow fever mosquitoes (Aedes aegypti): involvement of luminal Na+/K+-ATPase.

PubMed

Onken, Horst; Patel, Malay; Javoroncov, Margarita; Izeirovski, Sejmir; Moffett, Stacia B; Moffett, David F

2009-03-01

Recently, Na(+)/K(+)-ATPase has been detected in the luminal membrane of the anterior midgut of larval yellow fever mosquitoes (Aedes aegypti) with immunohistochemical techniques. In this study, the possible involvement of this ATPase in strong alkalinization was investigated on the level of whole larvae, isolated and perfused midgut preparations and on the molecular level of the Na(+)/K(+)-ATPase protein. Ouabain (5 mM) did not inhibit the capability of intact larval mosquitoes to alkalinize their anterior midgut. Also in isolated and perfused midgut preparations the perfusion of the lumen with ouabain (5 mM) did not result in a significant change of the transepithelial voltage or the capacity of luminal alkalinization. Na(+)/K(+)-ATPase activity was completely abolished when KCl was substituted with choline chloride, suggesting that the enzyme cannot act as an ATP-driven Na(+)/H(+)-exchanger. Altogether the results of the present investigation indicate that apical Na(+)/K(+)-ATPase is not of direct importance for strong luminal alkalinization in the anterior midgut of larval yellow fever mosquitoes.

QR images: optimized image embedding in QR codes.

PubMed

Garateguy, Gonzalo J; Arce, Gonzalo R; Lau, Daniel L; Villarreal, Ofelia P

2014-07-01

This paper introduces the concept of QR images, an automatic method to embed QR codes into color images with bounded probability of detection error. These embeddings are compatible with standard decoding applications and can be applied to any color image with full area coverage. The QR information bits are encoded into the luminance values of the image, taking advantage of the immunity of QR readers against local luminance disturbances. To mitigate the visual distortion of the QR image, the algorithm utilizes halftoning masks for the selection of modified pixels and nonlinear programming techniques to locally optimize luminance levels. A tractable model for the probability of error is developed and models of the human visual system are considered in the quality metric used to optimize the luminance levels of the QR image. To minimize the processing time, the optimization techniques proposed to consider the mechanics of a common binarization method and are designed to be amenable for parallel implementations. Experimental results show the graceful degradation of the decoding rate and the perceptual quality as a function the embedding parameters. A visual comparison between the proposed and existing methods is presented.

Gray-scale transform and evaluation for digital x-ray chest images on CRT monitor

NASA Astrophysics Data System (ADS)

Furukawa, Isao; Suzuki, Junji; Ono, Sadayasu; Kitamura, Masayuki; Ando, Yutaka

1997-04-01

In this paper, an experimental evaluation of a super high definition (SHD) imaging system for digital x-ray chest images is presented. The SHD imaging system is proposed as a platform for integrating conventional image media. We are involved in the use of SHD images in the total digitizing of medical records that include chest x-rays and pathological microscopic images, both which demand the highest level of quality among the various types of medical images. SHD images use progressive scanning and have a spatial resolution of 2000 by 2000 pixels or more and a temporal resolution (frame rate) of 60 frames/sec or more. For displaying medical x-ray images on a CRT, we derived gray scale transform characteristics based on radiologists' comments during the experiment, and elucidated the relationship between that gray scale transform and the linearization transform for maintaining the linear relationship with the luminance of film on a light box (luminance linear transform). We then carried out viewing experiments based on a five-stage evaluation. Nine radiologists participated in our experiment, and the ten cases evaluated included pulmonary fibrosis, lung cancer, and pneumonia. The experimental results indicated that conventional film images and those on super high definition CRT monitors have nearly the same quality. They also show that the gray scale transform for CRT images decided according to radiologists' comments agrees with the luminance linear transform in the high luminance region. And in the low luminance region, it was found that the gray scale transform had the characteristics of level expansion to increase the number of levels that can be expressed.

The effects of luminance contrast, colour combinations, font, and search time on brand icon legibility.

PubMed

Ko, Ya-Hsien

2017-11-01

This study explored and identified the effects of luminance contrast, colour combinations, font, and search time on brand icon legibility. A total of 108 participants took part in the experiment. As designed, legibility was measured as a function of the following independent variables: four levels of luminance contrast, sixteen target/background colour combinations, two fonts, and three search times. The results showed that a luminance contrast of 18:1 provided readers with the best legibility. Yellow on black, yellow on blue, and white on blue were the three most legible colour combinations. One of this study's unique findings was that colour combinations may play an even more important role than luminance contrast in the overall legibility of brand icon design. The 12-s search time corresponded with the highest legibility. Arial font was more legible than Times New Roman. These results provide some guidance for brand icon and product advertisement design. Copyright © 2017 Elsevier Ltd. All rights reserved.

Encoding of luminance and contrast by linear and nonlinear synapses in the retina.

PubMed

Odermatt, Benjamin; Nikolaev, Anton; Lagnado, Leon

2012-02-23

Understanding how neural circuits transmit information is technically challenging because the neural code is contained in the activity of large numbers of neurons and synapses. Here, we use genetically encoded reporters to image synaptic transmission across a population of sensory neurons-bipolar cells in the retina of live zebrafish. We demonstrate that the luminance sensitivities of these synapses varies over 10(4) with a log-normal distribution. About half the synapses made by ON and OFF cells alter their polarity of transmission as a function of luminance to generate a triphasic tuning curve with distinct maxima and minima. These nonlinear synapses signal temporal contrast with greater sensitivity than linear ones. Triphasic tuning curves increase the dynamic range over which bipolar cells signal light and improve the efficiency with which luminance information is transmitted. The most efficient synapses signaled luminance using just 1 synaptic vesicle per second per distinguishable gray level. Copyright © 2012 Elsevier Inc. All rights reserved.

Luminance gradient at object borders communicates object location to the human oculomotor system.

PubMed

Kilpeläinen, Markku; Georgeson, Mark A

2018-01-25

The locations of objects in our environment constitute arguably the most important piece of information our visual system must convey to facilitate successful visually guided behaviour. However, the relevant objects are usually not point-like and do not have one unique location attribute. Relatively little is known about how the visual system represents the location of such large objects as visual processing is, both on neural and perceptual level, highly edge dominated. In this study, human observers made saccades to the centres of luminance defined squares (width 4 deg), which appeared at random locations (8 deg eccentricity). The phase structure of the square was manipulated such that the points of maximum luminance gradient at the square's edges shifted from trial to trial. The average saccade endpoints of all subjects followed those shifts in remarkable quantitative agreement. Further experiments showed that the shifts were caused by the edge manipulations, not by changes in luminance structure near the centre of the square or outside the square. We conclude that the human visual system programs saccades to large luminance defined square objects based on edge locations derived from the points of maximum luminance gradients at the square's edges.

Interocular suppression in normal and amblyopic vision: spatio-temporal properties.

PubMed

Huang, Pi-Chun; Baker, Daniel H; Hess, Robert F

2012-10-31

We measured the properties of interocular suppression in strabismic amblyopes and compared these to dichoptic masking in binocularly normal observers. We used a dichoptic version of the well-established probed-sinewave paradigm that measured sensitivity to a brief target stimulus (one of four letters to be discriminated) in the amblyopic eye at different times relative to a suppression-inducing mask in the fixing eye. This was done using both sinusoidal steady state and transient approaches. The suppression-inducing masks were either modulations of luminance or contrast (full field, just overlaying the target, or just surrounding the target). Our results were interpreted using a descriptive model that included contrast gain control and spatio-temporal filtering prior to excitatory binocular combination. The suppression we measured, other than in magnitude, was not fundamentally different from normal dichoptic masking: lowpass spatio-temporal properties with similar contributions from both surround and overlay suppression.

Extraplanar H II Regions in Spiral Galaxies. I. Low-metallicity Gas Accreting through the Disk-halo Interface of NGC 4013

NASA Astrophysics Data System (ADS)

Howk, J. Christopher; Rueff, Katherine M.; Lehner, Nicolas; Wotta, Christopher B.; Croxall, Kevin; Savage, Blair D.

2018-04-01

The interstellar thick disks of galaxies serve as the interface between the thin star-forming disk, where feedback-driven outflows originate, and the distant halo, the repository for accreted gas. We present optical emission line spectroscopy of a luminous, thick disk H II region located at z = 860 pc above the plane of the spiral galaxy NGC 4013 taken with the Multi-Object Double Spectrograph on the Large Binocular Telescope. This nebula, with an Hα luminosity ∼4–7 times that of the Orion nebula, surrounds a luminous cluster of young, hot stars that ionize the surrounding interstellar gas of the thick disk, providing a measure of the properties of that gas. We demonstrate that strong emission line methods can provide accurate measures of relative abundances between pairs of H II regions. From our emission line spectroscopy, we show that the metal content of the thick disk H II region is a factor of ≈2 lower than gas in H II regions at the midplane of this galaxy (with the relative abundance of O in the thick disk lower by ‑0.32 ± 0.09 dex). This implies incomplete mixing of material in the thick disk on small scales (hundreds of parsecs) and that there is accretion of low-metallicity gas through the thick disks of spirals. The inclusion of low-metallicity gas this close to the plane of NGC 4013 is reminiscent of the recently proposed “fountain-driven” accretion models.

A novel bipolar phosphorescent host for highly efficient deep-red OLEDs at a wide luminance range of 1000-10 000 cd m(-2).

PubMed

Feng, Yansong; Li, Ping; Zhuang, Xuming; Ye, Kaiqi; Peng, Tai; Liu, Yu; Wang, Yue

2015-08-14

A novel phosphorescent host FPYPCA possessing the bipolar charge transporting ability realizes the most efficient deep-red PhOLED, which maintains very high-level EQEs of >23% at rather a high and wide luminance range of 1000-10 000 cd m(-2).

Assessment of display performance for medical imaging systems: Executive summary of AAPM TG18 report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samei, Ehsan; Badano, Aldo; Chakraborty, Dev

Digital imaging provides an effective means to electronically acquire, archive, distribute, and view medical images. Medical imaging display stations are an integral part of these operations. Therefore, it is vitally important to assure that electronic display devices do not compromise image quality and ultimately patient care. The AAPM Task Group 18 (TG18) recently published guidelines and acceptance criteria for acceptance testing and quality control of medical display devices. This paper is an executive summary of the TG18 report. TG18 guidelines include visual, quantitative, and advanced testing methodologies for primary and secondary class display devices. The characteristics, tested in conjunction withmore » specially designed test patterns (i.e., TG18 patterns), include reflection, geometric distortion, luminance, the spatial and angular dependencies of luminance, resolution, noise, glare, chromaticity, and display artifacts. Geometric distortions are evaluated by linear measurements of the TG18-QC test pattern, which should render distortion coefficients less than 2%/5% for primary/secondary displays, respectively. Reflection measurements include specular and diffuse reflection coefficients from which the maximum allowable ambient lighting is determined such that contrast degradation due to display reflection remains below a 20% limit and the level of ambient luminance (L{sub amb}) does not unduly compromise luminance ratio (LR) and contrast at low luminance levels. Luminance evaluation relies on visual assessment of low contrast features in the TG18-CT and TG18-MP test patterns, or quantitative measurements at 18 distinct luminance levels of the TG18-LN test patterns. The major acceptable criteria for primary/secondary displays are maximum luminance of greater than 170/100 cd/m{sup 2}, LR of greater than 250/100, and contrast conformance to that of the grayscale standard display function (GSDF) of better than 10%/20%, respectively. The angular response is tested to ascertain the viewing cone within which contrast conformance to the GSDF is better than 30%/60% and LR is greater than 175/70 for primary/secondary displays, or alternatively, within which the on-axis contrast thresholds of the TG18-CT test pattern remain discernible. The evaluation of luminance spatial uniformity at two distinct luminance levels across the display faceplate using TG18-UNL test patterns should yield nonuniformity coefficients smaller than 30%. The resolution evaluation includes the visual scoring of the CX test target in the TG18-QC or TG18-CX test patterns, which should yield scores greater than 4/6 for primary/secondary displays. Noise evaluation includes visual evaluation of the contrast threshold in the TG18-AFC test pattern, which should yield a minimum of 3/2 targets visible for primary/secondary displays. The guidelines also include methodologies for more quantitative resolution and noise measurements based on MTF and NPS analyses. The display glare test, based on the visibility of the low-contrast targets of the TG18-GV test pattern or the measurement of the glare ratio (GR), is expected to yield scores greater than 3/1 and GRs greater than 400/150 for primary/secondary displays. Chromaticity, measured across a display faceplate or between two display devices, is expected to render a u{sup '},v{sup '} color separation of less than 0.01 for primary displays. The report offers further descriptions of prior standardization efforts, current display technologies, testing prerequisites, streamlined procedures and timelines, and TG18 test patterns.« less

O6-methylguanine-DNA methyltransferase as a prognostic and predictive marker for basal-like breast cancer treated with cyclophosphamide-based chemotherapy

PubMed Central

ISONO, SAYURI; FUJISHIMA, MAKOTO; AZUMI, TATSUYA; HASHIMOTO, YUKIHIKO; KOMOIKE, YOSHIFUMI; YUKAWA, MASAO; WATATANI, MASAHIRO

2014-01-01

The O6-methylguanine-DNA methyltransferase (MGMT) protein protects cells from alkylating agents by removing alkyl groups from the O6-position of guanine. However, its effect on DNA damage induced by cyclophosphamide (CPM) is unclear. The present study investigated whether MGMT expression was correlated with prognosis in patients with breast cancer that was managed according to a common therapeutic protocol or treated with CPM-based chemotherapy. The intrinsic subtypes and MGMT protein expression levels were assessed in 635 consecutive patients with breast cancer using immunohistochemistry. In total, 425 (67%) luminal A, 95 (15%) luminal B, 47 (7%) human epidermal growth factor receptor-2+/estrogen receptor− (HER2+/ER−) and 48 (8%) basal-like subtypes were identified. Of these, MGMT positivity was identified in 398 (63%) of 635 breast cancers; 68% of luminal A, 67% of luminal B, 30% of HER2+/ER− and 46% of basal-like subtypes were positive. The overall survival (OS) and disease-free survival (DFS) rates did not significantly differ according to the MGMT status among patients with luminal A, luminal B or HER2+/ER− subtypes, and patients with MGMT-negative basal-like cancers tended to have a longer DFS, but not a significantly longer OS time. CPM-containing chemotherapy was administered to 26%, 40%, 47% and 31% of patients with luminal A, luminal B, HER2+/ER− and basal-like tumors, respectively. Although the MGMT status and clinical outcomes of patients with the luminal A, luminal B or HER2+/ER− subtypes treated with CPM were not significantly correlated, the patients with MGMT-negative basal-like tumors who received CPM exhibited significantly improved DFS and OS compared with the CPM-treated patients with MGMT-positive tumors. MGMT may be a useful prognostic and predictive marker for CPM-containing chemotherapy in basal-like breast cancer. PMID:24932232

O6-methylguanine-DNA methyltransferase as a prognostic and predictive marker for basal-like breast cancer treated with cyclophosphamide-based chemotherapy.

PubMed

Isono, Sayuri; Fujishima, Makoto; Azumi, Tatsuya; Hashimoto, Yukihiko; Komoike, Yoshifumi; Yukawa, Masao; Watatani, Masahiro

2014-06-01

The O 6 -methylguanine-DNA methyltransferase (MGMT) protein protects cells from alkylating agents by removing alkyl groups from the O 6 -position of guanine. However, its effect on DNA damage induced by cyclophosphamide (CPM) is unclear. The present study investigated whether MGMT expression was correlated with prognosis in patients with breast cancer that was managed according to a common therapeutic protocol or treated with CPM-based chemotherapy. The intrinsic subtypes and MGMT protein expression levels were assessed in 635 consecutive patients with breast cancer using immunohistochemistry. In total, 425 (67%) luminal A, 95 (15%) luminal B, 47 (7%) human epidermal growth factor receptor-2 + /estrogen receptor - (HER2 + /ER - ) and 48 (8%) basal-like subtypes were identified. Of these, MGMT positivity was identified in 398 (63%) of 635 breast cancers; 68% of luminal A, 67% of luminal B, 30% of HER2 + /ER - and 46% of basal-like subtypes were positive. The overall survival (OS) and disease-free survival (DFS) rates did not significantly differ according to the MGMT status among patients with luminal A, luminal B or HER2 + /ER - subtypes, and patients with MGMT-negative basal-like cancers tended to have a longer DFS, but not a significantly longer OS time. CPM-containing chemotherapy was administered to 26%, 40%, 47% and 31% of patients with luminal A, luminal B, HER2 + /ER - and basal-like tumors, respectively. Although the MGMT status and clinical outcomes of patients with the luminal A, luminal B or HER2 + /ER - subtypes treated with CPM were not significantly correlated, the patients with MGMT-negative basal-like tumors who received CPM exhibited significantly improved DFS and OS compared with the CPM-treated patients with MGMT-positive tumors. MGMT may be a useful prognostic and predictive marker for CPM-containing chemotherapy in basal-like breast cancer.

Lunar eclipse photometry: absolute luminance measurements and modeling.

PubMed

Hernitschek, Nina; Schmidt, Elmar; Vollmer, Michael

2008-12-01

The Moon's time-dependent luminance was determined during the 9 February 1990 and 3 March 2007 total lunar eclipses by using calibrated, industry standard photometers. After the results were corrected to unit air mass and to standard distances for both Moon and Sun, an absolute calibration was accomplished by using the Sun's known luminance and a pre-eclipse lunar albedo of approximately 13.5%. The measured minimum level of brightness in the total phase of both eclipses was relatively high, namely -3.32 m(vis) and -1.7 m(vis), which hints at the absence of pronounced stratospheric aerosol. The light curves were modeled in such a way as to let the Moon move through an artificial Earth shadow composed of a multitude of disk and ring zones, containing a relative luminance data set from an atmospheric radiative transfer calculation.

Optimal front light design for reflective displays under different ambient illumination

NASA Astrophysics Data System (ADS)

Wang, Sheng-Po; Chang, Ting-Ting; Li, Chien-Ju; Bai, Yi-Ho; Hu, Kuo-Jui

2011-01-01

The goal of this study is to find out the optimal luminance and color temperature of front light for reflective displays in different ambient illumination by conducting series of psychophysical experiments. A color and brightness tunable front light device with ten LED units was built and been calibrated to present 256 luminance levels and 13 different color temperature at fixed luminance of 200 cd/m2. The experiment results revealed the best luminance and color temperature settings for human observers under different ambient illuminant, which could also assist the e-paper manufacturers to design front light device, and present the best image quality on reflective displays. Furthermore, a similar experiment procedure was conducted by utilizing new flexible e-signage display developed by ITRI and an optimal front light device for the new display panel has been designed and utilized.

An assessment of the performance and quality control procedures of PACS workstation monitors used in Irish radiology departments

NASA Astrophysics Data System (ADS)

Wade, Cherrie; Brennan, Patrick C.; Mc Entee, Mark F.

2005-04-01

Diagnostic efficacy in soft-copy reporting relies heavily on the quality of workstation monitors and an investigation performed in 2002 demonstrated that CRT monitors in Dublin imaging departments were not operating at optimal levels. The current work examines the performance of CRTs being used in Dublin and other parts of Ireland to establish if problems reported in the earlier work have been rectified. All hospitals performing soft-copy reporting for general radiology using CRTs were included in the work. Examination of ambient lighting, calibration of monitors and analysis of CRT performance using the SMPTE test pattern and a selection of the AAPM test images was performed. Maximum luminance, spatial uniformity of luminance, temporal luminance stability, gamma, geometry, sharpness, veiling glare and spatial resolution of each monitor was evaluated. Ambient lighting in all reporting areas was within recommended levels. All the monitors were calibrated appropriately and were performing at acceptable levels for maximum luminance and temporal stability and only one of the thirty-three investigated failed to reach the standard for spatial uniformity. In contrast a number of the CRTs investigated showed poor adherence to acceptable levels for geometrical distortions, veiling glare and spatial resolution all of which are important influencers of image quality. Gamma values also appeared to be low for a number of monitors but this interpretation is provisional and subject to the establishment of ratified guideline values. The results demonstrate that although some improvement on the previous situation is evident, greater adherence to acceptable levels is required for certain parameters.

The Two-Component Virial Theorem and the Physical Properties of Stellar Systems.

PubMed

Dantas; Ribeiro; Capelato; de Carvalho RR

2000-01-01

Motivated by present indirect evidence that galaxies are surrounded by dark matter halos, we investigate whether their physical properties can be described by a formulation of the virial theorem that explicitly takes into account the gravitational potential term representing the interaction of the dark halo with the baryonic or luminous component. Our analysis shows that the application of such a "two-component virial theorem" not only accounts for the scaling relations displayed by, in particular, elliptical galaxies, but also for the observed properties of all virialized stellar systems, ranging from globular clusters to galaxy clusters.

High-resolution observations of radio-source hot spots at 329 MHz

NASA Technical Reports Server (NTRS)

Linfield, R.; Simon, R. S.

1984-01-01

The hot spots of several luminous double radio sources have been observed at 329 MHz with VLBI at fringe spacings ranging from 0.05 to 0.70 arcsec. Two out of two high-redshift (z = about 0.5) sources, but only one of six low-redshift (z = about 0.05) sources, were detected. For the low-redshift source (3C 234) which was detected, either the hot spot is larger at 329 MHz than at 15 GHz, or else the brightness contrast between it and the surrounding lobe is lower at the lower frequency.

Study of coherence effects in a four-level Ξ‑Λ type system

NASA Astrophysics Data System (ADS)

Yadav, Kavita; Wasan, Ajay

2018-05-01

We theoretically study the two- and three-photon coherence in a Ξ‑Λ type four-level system for stationary as well moving atoms at the room temperature using density matrix formalism. We discuss the role of dressed states to elucidate the electromagnetically induced transparency and electromagnetically induced absorption phenomena. The presence of the third field induces absorption at the line centre. A negative dispersion slope owing to the enhanced absorption results in super-luminal light propagation and the group index variation with the coupling field is switched from sub- to super-luminal. Group index with probe detuning shows super-luminal light propagation behaviour at the dressed state positions. The three optical fields trigger four-wave mixing as a result of the third order nonlinearity. The transient evolution is also discussed for optimum strengths of the coupling and drive fields to realize the optical switching in the system.

Near-field visual acuity of pigeons: effects of head location and stimulus luminance.

PubMed

Hodos, W; Leibowitz, R W; Bonbright, J C

1976-03-01

Two pigeons were trained to discriminate a grating stimulus from a blank stimulus of equivalent luminance in a three-key chamber. The stimuli and blanks were presented behind a transparent center key. The procedure was a conditional discrimination in which pecks on the left key were reinforced if the blank had been present behind the center key and pecks on the right key were reinforced if the grating had been present behind the center key. The spatial frequency of the stimuli was varied in each session from four to 29.5 lines per millimeter in accordance with a variation of the method of constant stimuli. The number of lines per millimeter that the subjects could discriminate at threshold was determined from psychometric functions. Data were collected at five values of stimulus luminance ranging from--0.07 to 3.29 log cd/m2. The distance from the stimulus to the anterior nodal point of the eye, which was determined from measurements taken from high-speed motion-picture photographs of three additional pigeons and published intraocular measurements, was 62.0 mm. This distance and the grating detection thresholds were used to calculate the visual acuity of the birds at each level of luminance. Acuity improved with increasing luminance to a peak value of 0.52, which corresponds to a visual angle of 1.92 min, at a luminance of 2.33 log cd/m2. Further increase in luminance produced a small decline in acuity.

GAFFE: a gaze-attentive fixation finding engine.

PubMed

Rajashekar, U; van der Linde, I; Bovik, A C; Cormack, L K

2008-04-01

The ability to automatically detect visually interesting regions in images has many practical applications, especially in the design of active machine vision and automatic visual surveillance systems. Analysis of the statistics of image features at observers' gaze can provide insights into the mechanisms of fixation selection in humans. Using a foveated analysis framework, we studied the statistics of four low-level local image features: luminance, contrast, and bandpass outputs of both luminance and contrast, and discovered that image patches around human fixations had, on average, higher values of each of these features than image patches selected at random. Contrast-bandpass showed the greatest difference between human and random fixations, followed by luminance-bandpass, RMS contrast, and luminance. Using these measurements, we present a new algorithm that selects image regions as likely candidates for fixation. These regions are shown to correlate well with fixations recorded from human observers.

An integrated genomics analysis of epigenetic subtypes in human breast tumors links DNA methylation patterns to chromatin states in normal mammary cells.

PubMed

Holm, Karolina; Staaf, Johan; Lauss, Martin; Aine, Mattias; Lindgren, David; Bendahl, Pär-Ola; Vallon-Christersson, Johan; Barkardottir, Rosa Bjork; Höglund, Mattias; Borg, Åke; Jönsson, Göran; Ringnér, Markus

2016-02-29

Aberrant DNA methylation is frequently observed in breast cancer. However, the relationship between methylation patterns and the heterogeneity of breast cancer has not been comprehensively characterized. Whole-genome DNA methylation analysis using Illumina Infinium HumanMethylation450 BeadChip arrays was performed on 188 human breast tumors. Unsupervised bootstrap consensus clustering was performed to identify DNA methylation epigenetic subgroups (epitypes). The Cancer Genome Atlas data, including methylation profiles of 669 human breast tumors, was used for validation. The identified epitypes were characterized by integration with publicly available genome-wide data, including gene expression levels, DNA copy numbers, whole-exome sequencing data, and chromatin states. We identified seven breast cancer epitypes. One epitype was distinctly associated with basal-like tumors and with BRCA1 mutations, one epitype contained a subset of ERBB2-amplified tumors characterized by multiple additional amplifications and the most complex genomes, and one epitype displayed a methylation profile similar to normal epithelial cells. Luminal tumors were stratified into the remaining four epitypes, with differences in promoter hypermethylation, global hypomethylation, proliferative rates, and genomic instability. Specific hyper- and hypomethylation across the basal-like epitype was rare. However, we observed that the candidate genomic instability drivers BRCA1 and HORMAD1 displayed aberrant methylation linked to gene expression levels in some basal-like tumors. Hypomethylation in luminal tumors was associated with DNA repeats and subtelomeric regions. We observed two dominant patterns of aberrant methylation in breast cancer. One pattern, constitutively methylated in both basal-like and luminal breast cancer, was linked to genes with promoters in a Polycomb-repressed state in normal epithelial cells and displayed no correlation with gene expression levels. The second pattern correlated with gene expression levels and was associated with methylation in luminal tumors and genes with active promoters in normal epithelial cells. Our results suggest that hypermethylation patterns across basal-like breast cancer may have limited influence on tumor progression and instead reflect the repressed chromatin state of the tissue of origin. On the contrary, hypermethylation patterns specific to luminal breast cancer influence gene expression, may contribute to tumor progression, and may present an actionable epigenetic alteration in a subset of luminal breast cancers.

ATP mediates flow-induced NO production in thick ascending limbs

PubMed Central

Hong, Nancy J.; Garvin, Jeffrey L.

2012-01-01

Mechanical stimulation caused by increasing flow induces nucleotide release from many cells. Luminal flow and extracellular ATP stimulate production of nitric oxide (NO) in thick ascending limbs. However, the factors that mediate flow-induced NO production are unknown. We hypothesized that luminal flow stimulates thick ascending limb NO production via ATP. We measured NO in isolated, perfused rat thick ascending limbs using the fluorescent dye DAF FM. The rate of increase in dye fluorescence reflects NO accumulation. Increasing luminal flow from 0 to 20 nl/min stimulated NO production from 17 ± 16 to 130 ± 37 arbitrary units (AU)/min (P < 0.02). Increasing flow from 0 to 20 nl/min raised ATP release from 4 ± 1 to 21 ± 6 AU/min (P < 0.04). Hexokinase (10 U/ml) plus glucose, which consumes ATP, completely prevented the measured increase in ATP. Luminal flow did not increase NO production in the presence of luminal and basolateral hexokinase (10 U/ml). When flow was increased with the ATPase apyrase in both luminal and basolateral solutions (5 U/ml), NO levels did not change significantly. The P2 receptor antagonist suramin (300 μmol/l) reduced flow-induced NO production by 83 ± 25% (P < 0.03) when added to both and basolateral sides. Luminal hexokinase decreased flow-induced NO production from 205.6 ± 85.6 to 36.6 ± 118.6 AU/min (P < 0.02). Basolateral hexokinase also reduced flow-induced NO production. The P2X receptor-selective antagonist NF023 (200 μmol/l) prevented flow-induced NO production when added to the basolateral side but not the luminal side. We conclude that ATP mediates flow-induced NO production in the thick ascending limb likely via activation of P2Y receptors in the luminal and P2X receptors in the basolateral membrane. PMID:22496412

Google Glass Glare: disability glare produced by a head-mounted visual display.

PubMed

Longley, Chris; Whitaker, David

2016-03-01

Head mounted displays are a type of wearable technology - a market that is projected to expand rapidly over the coming years. Probably the most well known example is the device Google Glass (or 'Glass'). Here we investigate the extent to which the device display can interfere with normal visual function by producing monocular disability glare. Contrast sensitivity was measured in two normally sighted participants, 32 and 52 years of age. Data were recorded for the right eye, the left eye and then again in a binocular condition. Measurements were taken both with and without the Glass in place, across a range of stimulus luminance levels using a two-alternative forced-choice methodology. The device produced a significant reduction in contrast sensitivity in the right eye (>0.5 log units). The level of disability glare increased as stimulus luminance was reduced in a manner consistent with intraocular light scatter, resulting in a veiling retinal illuminance. Sensitivity in the left eye was unaffected. A significant reduction in binocular contrast sensitivity occurred at lower luminance levels due to a loss of binocular summation, although binocular sensitivity was not found to fall below the sensitivity of the better monocular level (binocular inhibition). Head mounted displays such as Google Glass have the potential to cause significant disability glare in the eye exposed to the visual display, particularly under conditions of low luminance. They can also cause a more modest binocular reduction in sensitivity by eliminating the benefits of binocular summation. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

The integrative epigenomic-transcriptomic landscape of ER positive breast cancer.

PubMed

Gao, Yang; Jones, Allison; Fasching, Peter A; Ruebner, Matthias; Beckmann, Matthias W; Widschwendter, Martin; Teschendorff, Andrew E

2015-01-01

While recent integrative analyses of copy number and gene expression data in breast cancer have revealed a complex molecular landscape with multiple subtypes and many oncogenic/tumour suppressor driver events, much less is known about the role of DNA methylation in shaping breast cancer taxonomy and defining driver events. Here, we applied a powerful integrative network algorithm to matched DNA methylation and RNA-Seq data for 724 estrogen receptor (ER)-positive (ER+) breast cancers and 111 normal adjacent tissue specimens from The Cancer Genome Atlas (TCGA) project, in order to identify putative epigenetic driver events and to explore the resulting molecular taxonomy. This revealed the existence of nine functionally deregulated epigenetic hotspots encompassing a total of 146 genes, which we were able to validate in independent data sets encompassing over 1000 ER+ breast cancers. Integrative clustering of the matched messenger RNA (mRNA) and DNA methylation data over these genes resulted in only two clusters, which correlated very strongly with the luminal-A and luminal B subtypes. Overall, luminal-A and luminal-B breast cancers shared the same epigenetically deregulated hotspots but with luminal-B cancers exhibiting increased aberrant DNA methylation patterns relative to normal tissue. We show that increased levels of DNA methylation and mRNA expression deviation from the normal state define a marker of poor prognosis. Our data further implicates epigenetic silencing of WNT signalling antagonists and bone morphogenetic proteins (BMP) as key events underlying both luminal subtypes but specially of luminal-B breast cancer. Finally, we show that DNA methylation changes within the identified epigenetic interactome hotspots do not exhibit mutually exclusive patterns within the same cancer sample, instead exhibiting coordinated changes within the sample. Our results indicate that the integrative DNA methylation and transcriptomic landscape of ER+ breast cancer is surprisingly homogeneous, defining two main subtypes which strongly correlate with luminal-A/B subtype status. In particular, we identify WNT and BMP signalling as key epigenetically deregulated tumour suppressor pathways in luminal ER+ breast cancer, with increased deregulation seen in luminal-B breast cancer.

Constraints on the Progenitor of SN 2010jl and Pre-existing Hot Dust in its Surrounding Medium

NASA Technical Reports Server (NTRS)

Dwek, Eli; Arendt, Richard G.; Fox, Ori D.; Kelly, Patrick L.; Smith, Nathan; Van Dyk, Schuyler D.; Filippenko, Alexei, V.; Andrews, Jennifer; Shivvers, Isaac

2017-01-01

A search for the progenitor of SN 2010jl, an unusually luminous core-collapse supernova of Type IIn, using pre-explosion Hubble/WFPC2 and Spitzer/IRAC images of the region, yielded upper limits on the UV and near infrared (IR) fluxes from any candidate star. These upper limits constrain the luminosity and effective temperature of the progenitor, the mass of any pre-existing dust in its surrounding circumstellar medium (CSM), and dust proximity to the star. A lower limit on the CSM dust mass is required to hide a luminous progenitor from detection by Hubble. Upper limits on the CSM dust mass and constraints on its proximity to the star are set by requiring that the absorbed and reradiated IR emission not exceed the IRAC upper limits. Using the combined extinction-IR emission constraints, we present viable M(sub d)-R(sub 1) combinations, where M(sub d) and R(sub 1) are the CSM dust mass and its inner radius. These depend on the CSM outer radius, dust composition and grain size, and the properties of the progenitor. The results constrain the pre-supernova evolution of the progenitor, and the nature and origin of the observed post-explosion IR emission from SN 2010jl. In particular, an eta Car-type progenitor will require at least 4 mag of visual extinction to avoid detection by Hubble. This can be achieved with dust masses greater than approximately equal to 10(exp -3) solar mass (less than the estimated 0.2-0.5 solar mass around eta Car), which must be located at distances of greater than approximately equal to 10(exp 16) cm from the star to avoid detection by Spitzer.

Hubble Peers at the Heart of a Spiral Galaxy

NASA Image and Video Library

2014-03-21

This new Hubble image is centered on NGC 5793, a spiral galaxy over 150 million light-years away in the constellation of Libra. This galaxy has two particularly striking features: a beautiful dust lane and an intensely bright center — much brighter than that of our own galaxy, or indeed those of most spiral galaxies we observe. NGC 5793 is a Seyfert galaxy. These galaxies have incredibly luminous centers that are thought to be caused by hungry supermassive black holes — black holes that can be billions of times the size of the sun — that pull in and devour gas and dust from their surroundings. This galaxy is of great interest to astronomers for many reasons. For one, it appears to house objects known as masers. Whereas lasers emit visible light, masers emit microwave radiation. The term "masers" comes from the acronym Microwave Amplification by Stimulated Emission of Radiation. Maser emission is caused by particles that absorb energy from their surroundings and then re-emit this in the microwave part of the spectrum. Naturally occurring masers, like those observed in NGC 5793, can tell us a lot about their environment; we see these kinds of masers in areas where stars are forming. In NGC 5793 there are also intense mega-masers, which are thousands of times more luminous than the sun. Credit: NASA, ESA, and E. Perlman (Florida Institute of Technology) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Experimental investigations of an endoluminal ultrasound applicator for MR-guided thermal therapy of pancreatic cancer

NASA Astrophysics Data System (ADS)

Adams, Matthew; Salgaonkar, Vasant; Jones, Peter; Plata, Juan; Chen, Henry; Pauly, Kim Butts; Sommer, Graham; Diederich, Chris

2017-03-01

An MR-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. Minimally invasive ablation or hyperthermia treatment of pancreatic tumor tissue would be performed with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal tissue would be achieved with a water-cooled balloon surrounding the ultrasound transducers. This approach offers the capability of conformal volumetric therapy for fast treatment times, with control over the 3D spatial deposition of energy. Prototype endoluminal ultrasound applicators have been fabricated using 3D printed fixtures that seat two 3.2 or 5.6 MHz planar or curvilinear transducers and contain channels for wiring and water flow. Spiral surface coils have been integrated onto the applicator body to allow for device localization and tracking for therapies performed under MR guidance. Heating experiments with a tissue-mimicking phantom in a 3T MR scanner were performed and demonstrated capability of the prototype to perform volumetric heating through duodenal luminal tissue under real-time PRF-based MR temperature imaging (MRTI). Additional experiments were performed in ex vivo pig carcasses with the applicator inserted into the esophagus and aimed towards liver or soft tissue surrounding the spine under MR guidance. These experiments verified the capacity of heating targets up to 20-25 mm from the GI tract. Active device tracking and automated prescription of imaging and temperature monitoring planes through the applicator were made possible by using Hadamard encoded tracking sequences to obtain the coordinates of the applicator tracking coils. The prototype applicators have been integrated with an MR software suite that performs real-time device tracking and temperature monitoring.

Facial Contrast Is a Cross-Cultural Cue for Perceiving Age

PubMed Central

Porcheron, Aurélie; Mauger, Emmanuelle; Soppelsa, Frédérique; Liu, Yuli; Ge, Liezhong; Pascalis, Olivier; Russell, Richard; Morizot, Frédérique

2017-01-01

Age is a fundamental social dimension and a youthful appearance is of importance for many individuals, perhaps because it is a relevant predictor of aspects of health, facial attractiveness and general well-being. We recently showed that facial contrast—the color and luminance difference between facial features and the surrounding skin—is age-related and a cue to age perception of Caucasian women. Specifically, aspects of facial contrast decrease with age in Caucasian women, and Caucasian female faces with higher contrast look younger (Porcheron et al., 2013). Here we investigated faces of other ethnic groups and raters of other cultures to see whether facial contrast is a cross-cultural youth-related attribute. Using large sets of full face color photographs of Chinese, Latin American and black South African women aged 20–80, we measured the luminance and color contrast between the facial features (the eyes, the lips, and the brows) and the surrounding skin. Most aspects of facial contrast that were previously found to decrease with age in Caucasian women were also found to decrease with age in the other ethnic groups. Though the overall pattern of changes with age was common to all women, there were also some differences between the groups. In a separate study, individual faces of the 4 ethnic groups were perceived younger by French and Chinese participants when the aspects of facial contrast that vary with age in the majority of faces were artificially increased, but older when they were artificially decreased. Altogether these findings indicate that facial contrast is a cross-cultural cue to youthfulness. Because cosmetics were shown to enhance facial contrast, this work provides some support for the notion that a universal function of cosmetics is to make female faces look younger. PMID:28790941

Facial Contrast Is a Cross-Cultural Cue for Perceiving Age.

PubMed

Porcheron, Aurélie; Mauger, Emmanuelle; Soppelsa, Frédérique; Liu, Yuli; Ge, Liezhong; Pascalis, Olivier; Russell, Richard; Morizot, Frédérique

2017-01-01

Age is a fundamental social dimension and a youthful appearance is of importance for many individuals, perhaps because it is a relevant predictor of aspects of health, facial attractiveness and general well-being. We recently showed that facial contrast-the color and luminance difference between facial features and the surrounding skin-is age-related and a cue to age perception of Caucasian women. Specifically, aspects of facial contrast decrease with age in Caucasian women, and Caucasian female faces with higher contrast look younger (Porcheron et al., 2013). Here we investigated faces of other ethnic groups and raters of other cultures to see whether facial contrast is a cross-cultural youth-related attribute. Using large sets of full face color photographs of Chinese, Latin American and black South African women aged 20-80, we measured the luminance and color contrast between the facial features (the eyes, the lips, and the brows) and the surrounding skin. Most aspects of facial contrast that were previously found to decrease with age in Caucasian women were also found to decrease with age in the other ethnic groups. Though the overall pattern of changes with age was common to all women, there were also some differences between the groups. In a separate study, individual faces of the 4 ethnic groups were perceived younger by French and Chinese participants when the aspects of facial contrast that vary with age in the majority of faces were artificially increased, but older when they were artificially decreased. Altogether these findings indicate that facial contrast is a cross-cultural cue to youthfulness. Because cosmetics were shown to enhance facial contrast, this work provides some support for the notion that a universal function of cosmetics is to make female faces look younger.

Is switching from brand name to generic formulations of phenobarbital associated with loss of antiepileptic efficacy?: a pharmacokinetic study with two oral formulations (Luminal(®) vet, Phenoleptil(®)) in dogs.

PubMed

Bankstahl, Marion; Bankstahl, Jens P; Löscher, Wolfgang

2013-10-09

In human medicine, adverse outcomes associated with switching between bioequivalent brand name and generic antiepileptic drug products is a subject of concern among clinicians. In veterinary medicine, epilepsy in dogs is usually treated with phenobarbital, either with the standard brand name formulation Luminal(®) or the veterinary products Luminal(®) vet and the generic formulation Phenoleptil(®). Luminal(®) and Luminal(®) vet are identical 100 mg tablet formulations, while Phenoleptil(®) is available in the form of 12.5 and 50 mg tablets. Following approval of Phenoleptil(®) for treatment of canine epilepsy, it was repeatedly reported by clinicians and dog owners that switching from Luminal(®) (human tablets) to Phenoleptil(®) in epileptic dogs, which were controlled by treatment with Luminal(®), induced recurrence of seizures. In the present study, we compared bioavailability of phenobarbital after single dose administration of Luminal(®) vet vs. Phenoleptil(®) with a crossover design in 8 healthy Beagle dogs. Both drugs were administered at a dose of 100 mg/dog, resulting in 8 mg/kg phenobarbital on average. Peak plasma concentrations (Cmax) following Luminal(®) vet vs. Phenoleptil(®) were about the same in most dogs (10.9 ± 0.92 vs. 10.5 ± 0.77 μg/ml), and only one dog showed noticeable lower concentrations after Phenoleptil(®) vs. Luminal(®) vet. Elimination half-life was about 50 h (50.3 ± 3.1 vs. 52.9 ± 2.8 h) without differences between the formulations. The relative bioavailability of the two products (Phenoleptil(®) vs. Luminal(®) vet.) was 0.98 ± 0.031, indicating that both formulations resulted in about the same bioavailability. Overall, the two formulations did not differ significantly with respect to pharmacokinetic parameters when mean group parameters were compared. Thus, the reasons for the anecdotal reports, if true, that switching from the brand to the generic formulation of phenobarbital may lead to recurrence of seizures are obviously not related to a generally lower bioavailability of the generic formulation, although single dogs may exhibit lower plasma levels after the generic formulation that could be clinically meaningful.

Is switching from brand name to generic formulations of phenobarbital associated with loss of antiepileptic efficacy?: a pharmacokinetic study with two oral formulations (Luminal® vet, Phenoleptil®) in dogs

PubMed Central

2013-01-01

Background In human medicine, adverse outcomes associated with switching between bioequivalent brand name and generic antiepileptic drug products is a subject of concern among clinicians. In veterinary medicine, epilepsy in dogs is usually treated with phenobarbital, either with the standard brand name formulation Luminal® or the veterinary products Luminal® vet and the generic formulation Phenoleptil®. Luminal® and Luminal® vet are identical 100 mg tablet formulations, while Phenoleptil® is available in the form of 12.5 and 50 mg tablets. Following approval of Phenoleptil® for treatment of canine epilepsy, it was repeatedly reported by clinicians and dog owners that switching from Luminal® (human tablets) to Phenoleptil® in epileptic dogs, which were controlled by treatment with Luminal®, induced recurrence of seizures. In the present study, we compared bioavailability of phenobarbital after single dose administration of Luminal® vet vs. Phenoleptil® with a crossover design in 8 healthy Beagle dogs. Both drugs were administered at a dose of 100 mg/dog, resulting in 8 mg/kg phenobarbital on average. Results Peak plasma concentrations (Cmax) following Luminal® vet vs. Phenoleptil® were about the same in most dogs (10.9 ± 0.92 vs. 10.5 ± 0.77 μg/ml), and only one dog showed noticeable lower concentrations after Phenoleptil® vs. Luminal® vet. Elimination half-life was about 50 h (50.3 ± 3.1 vs. 52.9 ± 2.8 h) without differences between the formulations. The relative bioavailability of the two products (Phenoleptil® vs. Luminal® vet.) was 0.98 ± 0.031, indicating that both formulations resulted in about the same bioavailability. Conclusions Overall, the two formulations did not differ significantly with respect to pharmacokinetic parameters when mean group parameters were compared. Thus, the reasons for the anecdotal reports, if true, that switching from the brand to the generic formulation of phenobarbital may lead to recurrence of seizures are obviously not related to a generally lower bioavailability of the generic formulation, although single dogs may exhibit lower plasma levels after the generic formulation that could be clinically meaningful. PMID:24107313

Flicker sensitivity as a function of target area with and without temporal noise.

PubMed

Rovamo, J; Donner, K; Näsänen, R; Raninen, A

2000-01-01

Flicker sensitivities (1-30 Hz) in foveal, photopic vision were measured as functions of stimulus area with and without strong external white temporal noise. Stimuli were circular, sinusoidally flickering sharp-edged spots of variable diameters (0.25-4 degrees ) but constant duration (2 s), surrounded by a uniform equiluminant field. The data was described with a model comprising (i) low-pass filtering in the retina (R), with a modulation transfer function (MTF) of a form derived from responses of cones; (ii) normalisation of the temporal luminance distribution by the average luminance; (iii) high-pass filtering by postreceptoral neural pathways (P), with an MTF proportional to temporal frequency; (iv) addition of internal white neural noise (N(i)); (v) integration over a spatial window; and (vi) detection by a suboptimal temporal matched filter of efficiency eta. In strong external noise, flicker sensitivity was independent of spot area. Without external noise, sensitivity increased with the square root of stimulus area (Piper's law) up to a critical area (A(c)), where it reaches a maximum level (S(max)). Both A(c) and eta were monotonic functions of temporal frequency (f), such that log A(c) increased and log eta decreased linearly with log f. Remarkably, the increase in spatial integration area and the decrease in efficiency were just balanced, so A(c)(f)eta(f) was invariant against f. Thus the bandpass characteristics of S(max)(f) directly reflected the composite effect of the distal filters R(f) and P(f). The temporal equivalent (N(it)) of internal neural noise (N(i)) decreased in inverse proportion to spot area up to A(c) and then stayed constant indicating that spatially homogeneous signals and noise are integrated over the same area.

Ultraluminous X-ray Sources in NGC 6946.

NASA Astrophysics Data System (ADS)

Sánchez Cruces, Mónica; Rosado, Margarita; Fuentes-Carrera, Isaura L.

2016-07-01

Ultra-luminous X-ray sources (ULXs) are the most X-ray luminous off-nucleus objects in nearby galaxies with X-ray luminosities between 10^{39} - 10^{41} erg s^{-1} in the 0.5-10 keV band. Since these luminosities cannot be explained by the standard accretion of a stellar mass black hole, these sources are often associated with intermediate-mass black holes (IMBHs, 10^{2}-10^{4} solar masses). However significantly beamed stellar binary systems could also explain these luminosities. Observational knowledge of the angular distribution of the source emission is essential to decide between these two scenarios. In this work, we present the X-ray analysis of five ULXs in the spiral galaxy NGC 6949, along with the kinematical analysis of the ionized gas surrounding each of these sources. For all sources, X-ray observations reveal a typical ULX spectral shape (with a soft excess below 2 keV and a hard curvature above 2 keV) which can be fit with a power-law + multi-color disk model. However, even if ULXs are classified as point-like objects, one of the sources in this galaxy displays an elongated shape in the Chandra images. Regarding the analysis of the emission lines of the surrounding ˜300 pc around each ULX, scanning Fabry-Perot observations show composite profiles for three of the five ULXs. The main component of these profiles follows the global rotation of the galaxy, while the faint secondary component seems to be associated with asymmetrical gas expansion. These sources have also been located in archive images of NGC 6946 in different wavelengths in order to relate them to different physical processes occurring in this galaxy. Though ULXs are usually located in star formation regions, we find that two of the sources lie a few tenths of parsecs away from different HII regions. Based on the X-ray morphology of each ULX, the velocities and distribution of the surrounding gas, as well as the location of the source in the context of the whole galaxy, we give the most favorable scenario in each case in order to describe the multiwavelength properties of these sources.

SOFIA/FORCAST Observations of the Luminous Blue Variables in the Galactic Center

NASA Astrophysics Data System (ADS)

Lau, Ryan M.; Herter, T. L.; Morris, M.; Adams, J. D.

2014-01-01

Three Luminous Blue Variables (LBVs) are located in the vicinity of the Quintuplet Cluster in the Galactic Center: the Pistol star, G0.120-0.048, and qF362. We present imaging at 19, 25, 31, and 37 μm of the region containing these three LBVs obtained with SOFIA using FORCAST. We study the similarities and differences between the three LBVs and address the influence of the hot, massive stars in the adjacent Quintuplet Cluster and the local ambient medium in affecting the morphology, composition, and energetics of dust in the nebulae produced from their outflows. We observe the thermal emission from the Pistol nebula, the asymmetric, compressed shell of hot dust surrounding the Pistol star and provide the first detection of thermal emission from the symmetric, hot dust envelope surrounding G0.120-0.048. However, we do not detect any emission from hot dust surrounding qF362. The Pistol and G0.120-0.048 nebulae share an identical size scale of ˜ 0.7 pc which suggests that they have similar dynamical timescales (˜ 8000 yrs) assuming similar expansion velocities of ˜ 90 km/s. The Pistol nebula exhibits a temperature gradient decreasing from north to south with values ranging from 140 - 150 K. The G0.120-0.048 nebula, which is spherically symmetric about the star, exhibits an average dust temperature of ˜ 100 K. Fits to the spectral energy distribution (SED) of the Pistol nebula with the DustEm Radiative Transfer code indicate that the nebula is composed of separate distributions of large grains (≥ 500 Å) and small grains (˜ 10 Å). DustEm model fits to the G0.120-0.048 nebula SED indicate that it contains grains smaller than 500 Å which suggests it may also contain a population of small grains. The models predict that both nebulae have a total gas mass of ˜ 2.5 M⊙ (assuming Mg/Md = 100), and a total IR luminosity of ˜ 8 × 10^5 L⊙ for the Pistol and ˜ 10^5 L⊙ for G0.120-0.048.

Breast screen new South wales generally demonstrates good radiologic viewing conditions.

PubMed

Soh, BaoLin Pauline; Lee, Warwick; Diffey, Jennifer L; McEntee, Mark F; Kench, Peter L; Reed, Warren M; Brennan, Patrick C

2013-08-01

This study measured reading workstation monitors and the viewing environment currently available within BreastScreen New South Wales (BSNSW) centres to determine levels of adherence to national and international guidelines. Thirteen workstations from four BSNSW service centres were assessed using the American Association of Physicists in Medicine Task Group 18 Quality Control test pattern. Reading workstation monitor performance and ambient light levels when interpreting screening mammographic images were assessed using spectroradiometer CS-2000 and chroma meter CL-200. Overall, radiologic monitors within BSNSW were operating at good acceptable levels. Some non-adherence to published guidelines included the percentage difference in maximum luminance between pairs of primary monitors at individual workstations (61.5 % or 30.8 % of workstations depending on specific guidelines), maximum luminance (23.1 % of workstations), luminance non-uniformity (11.5 % of workstations) and minimum luminance (3.8 % of workstations). A number of ambient light measurements did not comply with the only available evidence-based guideline relevant to the methodology used in this study. Larger ambient light variations across sites are shown when monitors were switched off, suggesting that differences in ambient lighting between sites can be masked when a standard mammogram is displayed for photometric measurements. Overall, BSNSW demonstrated good adherence to available guidelines, although some non-compliance has been shown. Recently updated United Kingdom and Australian guidelines should help reduce confusion generated by the plethora and sometimes dated nature of currently available recommendations.

SU-E-P-29: Testing Display Monitors for GSDF Compliance - a Practical Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gauntt, D

2015-06-15

Purpose: To develop a simple technique for testing display monitors for compliance with the DICOM Grayscale Standard Display Function (GSDF), in accordance with the recommendations of AAPM Task Group 18. Methods: We have developed a spreadsheet that can be used to compare both the luminance response and contrast response of a display to the GSDF, using luminance measurements of the SMPTE test pattern. The contrast response compares the slope of the GSDF j-index as a function of pixel value to that of the GSDF function, and should lie within the range 0.85 to 1.15. Results: We present the results ofmore » measurements both of primary diagnostic displays and of ultrasound and acquisition workstations, all at a tertiary care hospital. The Barco displays in the radiographic reading rooms are GSDF compliant or nearly so, while those in the ultrasound reading rooms and at the acquisition workstations generally show significantly higher contrast at low luminance levels than they would if GSDF compliant, and lower contrast at high luminance levels. Conclusion: The spreadsheet that we developed allows a simple comparison of measured display contrast response to the GSDF. Although we used the SMPTE pattern, the same technique could be used with other grayscale patterns, such as TG18-QC and TG18-PQC.« less

Spatial contrast sensitivity at twilight: luminance, monocularity, and oxygenation.

PubMed

Connolly, Desmond M

2010-05-01

Visual performance in dim light is compromised by lack of oxygen (hypoxia). The possible influence of altered oxygenation on foveal contrast sensitivity under mesopic (twilight) viewing conditions is relevant to aircrew flying at night, including when using night vision devices, but is poorly documented. Foveal contrast sensitivity was measured binocularly and monocularly in 12 subjects at 7 spatial frequencies, ranging from 0.5 to approximately 16 cycles per degree, using sinusoidal Gabor patch gratings. Hypoxic performance breathing 14.1% oxygen, equivalent to altitude exposure at 3048 m (10,000 ft), was compared with breathing air at sea level (normoxia) at low photopic (28 cd x m(-2)), borderline upper mesopic (approximately 2.1 cd x m(-2)) and midmesopic (approximately 0.26 cd x m(-2)) luminance. Mesopic performance was also assessed breathing 100% oxygen (hyperoxia). Typical 'inverted U' log/log plots of the contrast sensitivity function were obtained, with elevated thresholds (reduced sensitivity) at lower luminance. Binocular viewing enhanced sensitivity by a factor approximating square root of 2 for most conditions, supporting neural summation of the contrast signal, but had greater influence at the lowest light level and highest spatial frequencies (8.26 and 16.51 cpd). Respiratory challenges had no effect. Contrast sensitivity is poorer when viewing monocularly and especially at midmesopic luminance, with relevance to night flying. The foveal contrast sensitivity function is unaffected by respiratory disturbance when twilight conditions favor cone vision, despite known effects on retinal illumination (pupil size). The resilience of the contrast sensitivity function belies the vulnerability of foveal low contrast acuity to mild hypoxia at mesopic luminance.

UNE FORME MICROTUBULAIRE ET PARACRISTALLINE DE RETICULUM ENDOPLASMIQUE DANS LES PHOTOCYTES DES ANNELIDES POLYNOINÆ

PubMed Central

Bassot, J. M.

1966-01-01

Luminous cells of polynoid worm elytra have been examined by methods of electron microscopy, with special attention focused on the fine structure of photogenic grains. These cells send apical prolongations into the mid-part of the elytra. The plasma membrane is very sinuous, and a special kind of desmosome links two portions of the same membrane. In addition to all the organelles which can be found in nonluminescent epithelial cells of the elytra, numerous photogenic grains are contained in their cytoplasm. These grains are composed of undulating microtubules measuring 200 A in diameter; their disposition in the grain is highly regular, and the grains appear as paracrystals. At the borders of the grains, the walls of the microtubules are often in continuity with those of the endoplasmic reticulum and with the external membrane of the nuclear envelope. Because of this fact, the microtubules of the grains may be considered a cytoplasmic organelle, representing a specialized form of the endoplasmic reticulum. The microtubules permit the repartition, inside and outside their walls, of two different products, one being forty-three times more abundant than the other; thus, the contact surface, in comparison to the volume, is greatly increased. The induction of the luminous reaction by change in the permeability of the microtubule walls, allowing contact between the two substances, is suggested as a working hypothesis. There is an evolution of the grains along the axis of the photocytes. The grains are often surrounded by progressively increasing amounts of glycogen. Their paracrystalline disposition is altered at the apex of the luminous cells. PMID:5971968

Polymeric immunoglobulin receptor in intestinal immune defense against the lumen-dwelling protozoan parasite Giardia.

PubMed

Davids, Barbara J; Palm, J E Daniel; Housley, Michael P; Smith, Jennifer R; Andersen, Yolanda S; Martin, Martin G; Hendrickson, Barbara A; Johansen, Finn-Eirik; Svärd, Staffan G; Gillin, Frances D; Eckmann, Lars

2006-11-01

The polymeric Ig receptor (pIgR) is conserved in mammals and has an avian homologue, suggesting evolutionarily important functions in vertebrates. It transports multimeric IgA and IgM across polarized epithelia and is highly expressed in the intestine, yet little direct evidence exists for its importance in defense against common enteric pathogens. In this study, we demonstrate that pIgR can play a critical role in intestinal defense against the lumen-dwelling protozoan parasite Giardia, a leading cause of diarrheal disease. The receptor was essential for the eradication of Giardia when high luminal IgA levels were required. Clearance of Giardia muris, in which IgA plays a dominant role, was severely compromised in pIgR-deficient mice despite significant fecal IgA output at 10% of normal levels. In contrast, eradication of the human strain Giardia lamblia GS/M, for which adaptive immunity is less IgA dependent in mice, was unaffected by pIgR deficiency, indicating that pIgR had no physiologic role when lower luminal IgA levels were sufficient for parasite elimination. Immune IgA was greatly increased in the serum of pIgR-deficient mice, conferred passive protection against Giardia, and recognized several conserved giardial Ags, including ornithine carbamoyltransferase, arginine deiminase, alpha-enolase, and alpha- and beta-giardins, that are also detected in human giardiasis. Corroborative observations were made in mice lacking the J chain, which is required for pIgR-dependent transepithelial IgA transport. These results, together with prior data on pIgR-mediated immune neutralization of luminal cholera toxin, suggest that pIgR is essential in intestinal defense against pathogenic microbes with high-level and persistent luminal presence.

The Quantized Geometry of Visual Space: The Coherent Computation of Depth, Form, and Lightness. Revised Version.

DTIC Science & Technology

1982-08-01

of sensitivity with background luminance, and the finitE capacity of visual short term memory are discussed in terms of a small set of ...binocular rivalry, reflectance rivalry, Fechner’s paradox, decrease of threshold contrast with increased number of cycles in a grating pattern, hysteresis...adaptation level tuning, Weber law modulation, shift of sensitivity with background luminance, and the finite capacity of visual

Facial contrast is a cue for perceiving health from the face.

PubMed

Russell, Richard; Porcheron, Aurélie; Sweda, Jennifer R; Jones, Alex L; Mauger, Emmanuelle; Morizot, Frederique

2016-09-01

How healthy someone appears has important social consequences. Yet the visual cues that determine perceived health remain poorly understood. Here we report evidence that facial contrast-the luminance and color contrast between internal facial features and the surrounding skin-is a cue for the perception of health from the face. Facial contrast was measured from a large sample of Caucasian female faces, and was found to predict ratings of perceived health. Most aspects of facial contrast were positively related to perceived health, meaning that faces with higher facial contrast appeared healthier. In 2 subsequent experiments, we manipulated facial contrast and found that participants perceived faces with increased facial contrast as appearing healthier than faces with decreased facial contrast. These results support the idea that facial contrast is a cue for perceived health. This finding adds to the growing knowledge about perceived health from the face, and helps to ground our understanding of perceived health in terms of lower-level perceptual features such as contrast. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Trophinin expression in the mouse uterus coincides with implantation and is hormonally regulated but not induced by implanting blastocysts.

PubMed

Suzuki, N; Nadano, D; Paria, B C; Kupriyanov, S; Sugihara, K; Fukuda, M N

2000-11-01

Trophinin mediates apical cell adhesion between two human cell lines, trophoblastic teratocarcinoma and endometrial adenocarcinoma. In humans, trophinin is specifically expressed in cells involved in implantation and early placentation. The present study was undertaken to establish trophinin expression by the mouse uterus. In the pregnant mouse uterus, trophinin transcripts are expressed during the time which coincides with the timing of blastocyst implantation. Trophinin is also expressed in the nonpregnant mouse uterus at estrus stage. Uteri from ovariectomized mice did not express trophinin, whereas strong expression was induced by estrogen but not by progesterone. Trophinin transcripts and protein were found in the pseudopregnant mouse uterus. No differences were detected in trophinin expression by the uteri in the pregnant, pseudopregnant, and pseudopregnant received blastocysts. In delayed implantation model, trophinin proteins were found in both luminal and glandular epithelium, whereas dormant blastocysts were negative for trophinin. Upon activation with estrogen, however, no significant changes were detected either in the blastocyst or in the uterus. These results indicate that ovarian hormones regulate trophinin expression by the mouse uterus, and that an implanting blastocyst has no effect on trophinin expression in the surrounding endometrial luminal epithelial cells.

Early gas stripping as the origin of the darkest galaxies in the Universe.

PubMed

Mayer, L; Kazantzidis, S; Mastropietro, C; Wadsley, J

2007-02-15

The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.

Ionized Gas Kinematics around an Ultra-luminous X-Ray Source in NGC 5252: Additional Evidence for an Off-nuclear AGN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Minjin; Ho, Luis C.; Im, Myungshin

2017-08-01

The Seyfert 2 galaxy NGC 5252 contains a recently identified ultra-luminous X-ray (ULX) source that has been suggested to be a possible candidate off-nuclear low-mass active galactic nucleus. We present follow-up optical integral-field unit observations obtained using Gemini Multi-Object Spectrographs on the Gemini-North telescope. In addition to confirming that the ionized gas in the vicinity of the ULX is kinematically associated with NGC 5252, the new observations reveal ordered motions consistent with rotation around the ULX. The close coincidence of the excitation source of the line-emitting gas with the position of the ULX further suggests that ULX itself is directlymore » responsible for the ionization of the gas. The spatially resolved measurements of [N ii] λ 6584/H α surrounding the ULX indicate a low gas-phase metallicity, consistent with those of other known low-mass active galaxies but not that of its more massive host galaxy. These findings strengthen the proposition that the ULX is not a background source but rather that it is the nucleus of a small, low-mass galaxy accreted by NGC 5252.« less

A Chandra Snapshot Survey of Extremely Red Quasars from SDSS BOSS and WISE

NASA Astrophysics Data System (ADS)

Garmire, Gordon

2017-09-01

We propose Chandra snapshot observations of a sample of 15 extremely red and highly luminous quasars at z > 2. These Type 1 objects have recently been discovered via the SDSS BOSS and WISE surveys, and they are among the most-luminous quasars in the Universe. They appear to be part of the missing evolutionary link as merger-induced starburst galaxies transform into typical ultraviolet luminous quasars. Our aim is to efficiently gather X-ray information about a sufficiently large sample of these objects that general conclusions about their basic X-ray properties, especially obscuration level and luminosity, can be drawn reliably. The results will also allow effective targeting of promising objects in longer X-ray spectroscopic observations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruuge, A; Erdi, Y; Mahmood, U

Purpose: The conformance of Primary Diagnostic Monitors (PDMs) to the DICOM GSDF is increasingly required by several state and city regulators. Our purpose was to quantitatively characterize the luminance performance of the internal, built in photometer of BARCO monitors against an externally calibrated luminance meter. Methods: Thirty one PDMs (BARCO) were included in our analysis. An externally calibrated photometer (RaySafe Solo Light) was used to measure the luminance and illuminance values. Measured monitors were located at various hospital sites, radiology physicians’ offices and radiology reading rooms. All measured PDMs were equipped with the manufacturer’s built-in photometers and connected to Barcomore » MediCal QA web service for manual and automatic quality control measurements. PDM combinations included 1, 2 and 4 monitors depending on the location. TG-18 and SMPTE test patterns were used to evaluate monitor performance. Results: All the PDMs exceeded the luminance ratio of 250:1, as required by NYC PDM guidelines. One PDM failed the NYC requirement for the minimal luminance level of 350 cd/m2. As compared to the external photometer, the difference in measurement of the maximum luminance with the built-in photometer was found to exceed 5% on 6 of the PDM measured, with a maximum deviation of 10%. The age of the monitors that failed was on average 5 years. All monitors passed the luminance uniformity test, which was 30% from the center of the monitor to the 4 corner locations. Four PDMs failed the Gray Scale Display Function (GSDF) calibration. Conclusion: For the consistent display of medical images and continued conformance with the DICOM GSDF standard, it is essential to compare the performance of the built-in photometer with an externally calibrated photometer for monitors that are older than 5 years.« less

Body weight and risk of molecular breast cancer subtypes among postmenopausal Mediterranean women.

PubMed

Crispo, A; Montella, M; Buono, G; Grimaldi, M; D'Aiuto, M; Capasso, I; Esposito, E; Amore, A; Nocerino, F; Augustin, L S A; Giudice, A; Di Bonito, M; Giuliano, M; Forestieri, V; De Laurentiis, M; Rinaldo, M; Ciliberto, G; De Placido, S; Arpino, G

2016-01-01

Breast cancer (BC) is the most common malignant tumor in women, obesity is associated with increased BC incidence and mortality and high levels of circulating insulin may negatively impact on cancer incidence. In the present study, we investigated whether the strength of several anthropometric and metabolic parameters varies between BC molecular subtypes. Eligible cases were 991 non-metastatic BC patients recruited between January 2009 and December 2013. Anthropometric, clinical and immunohistochemical features were measured. Multivariate logistic regression models were built to assess HER2 positive BC risk, comparing (a) triple positive (TP) with luminal A, luminal B and triple negative (TN) and (b) HER2-enriched group with luminal A, luminal B and TN. We stratified patients in pre- and post-menopause: significant differences emerged for luminal A in relation to age: they were more likely to be older compared to other groups. Among postmenopausal patients, the adjusted multivariate analysis showed that high BMI and high waist circumference were inversely correlated to TP subtype when compared to luminal B (OR=0.48 and OR=0.49, respectively). Conversely, HOMA-IR was a risk factor for TP when compared to luminal A and TN (OR=2.47 and OR=3.15, respectively). Our findings suggest a potential role of higher abdominal fat in the development of specific BC molecular subtypes in postmenopausal women. Moreover, they support a potential role of insulin resistance in the development of HER2 positive BC, although this role appears to be stronger when hormone receptors are co-expressed, suggesting a difference in the etiology of these two BC subtypes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Texture variations suppress suprathreshold brightness and colour variations.

PubMed

Schofield, Andrew J; Kingdom, Frederick A A

2014-01-01

Discriminating material changes from illumination changes is a key function of early vision. Luminance cues are ambiguous in this regard, but can be disambiguated by co-incident changes in colour and texture. Thus, colour and texture are likely to be given greater prominence than luminance for object segmentation, and better segmentation should in turn produce stronger grouping. We sought to measure the relative strengths of combined luminance, colour and texture contrast using a suprathreshhold, psychophysical grouping task. Stimuli comprised diagonal grids of circular patches bordered by a thin black line and contained combinations of luminance decrements with either violet, red, or texture increments. There were two tasks. In the Separate task the different cues were presented separately in a two-interval design, and participants indicated which interval contained the stronger orientation structure. In the Combined task the cues were combined to produce competing orientation structure in a single image. Participants had to indicate which orientation, and therefore which cue was dominant. Thus we established the relative grouping strength of each cue pair presented separately, and compared this to their relative grouping strength when combined. In this way we observed suprathreshold interactions between cues and were able to assess cue dominance at ecologically relevant signal levels. Participants required significantly more luminance and colour compared to texture contrast in the Combined compared to Separate conditions (contrast ratios differed by about 0.1 log units), showing that suprathreshold texture dominates colour and luminance when the different cues are presented in combination.

Acquiring skill at medical image inspection: learning localized in early visual processes

NASA Astrophysics Data System (ADS)

Sowden, Paul T.; Davies, Ian R. L.; Roling, Penny; Watt, Simon J.

1997-04-01

Acquisition of the skill of medical image inspection could be due to changes in visual search processes, 'low-level' sensory learning, and higher level 'conceptual learning.' Here, we report two studies that investigate the extent to which learning in medical image inspection involves low- level learning. Early in the visual processing pathway cells are selective for direction of luminance contrast. We exploit this in the present studies by using transfer across direction of contrast as a 'marker' to indicate the level of processing at which learning occurs. In both studies twelve observers trained for four days at detecting features in x- ray images (experiment one equals discs in the Nijmegen phantom, experiment two equals micro-calcification clusters in digitized mammograms). Half the observers examined negative luminance contrast versions of the images and the remainder examined positive contrast versions. On the fifth day, observers swapped to inspect their respective opposite contrast images. In both experiments leaning occurred across sessions. In experiment one, learning did not transfer across direction of luminance contrast, while in experiment two there was only partial transfer. These findings are consistent with the contention that some of the leaning was localized early in the visual processing pathway. The implications of these results for current medical image inspection training schedules are discussed.

Optimization of reading conditions for flat panel displays.

PubMed

Thomas, J A; Chakrabarti, K; Kaczmarek, R V; Maslennikov, A; Mitchell, C A; Romanyukha, A

2006-06-01

Task Group 18 (TG 18) of the American Association of Physicists in Medicine has developed guidelines for Assessment of Display Performance for Medical Imaging Systems. In this document, a method for determination of the maximum room lighting for displays is suggested. It is based on luminance measurements of a black target displayed on each display device at different room illuminance levels. Linear extrapolation of the above luminance measurements vs. room illuminance allows one to determine diffuse and specular reflection coefficients. TG 18 guidelines have established recommended maximum room lighting. It is based on the characterization of the display by its minimum and maximum luminance and the description of room by diffuse and specular coefficients. We carried out these luminance measurements for three selected displays to determine their optimum viewing conditions: one cathode ray tube and two flat panels. We found some problems with the application of the TG 18 guidelines to optimize viewing conditions for IBM T221 flat panels. Introduction of the requirement for minimum room illuminance allows a more accurate determination of the optimal viewing conditions (maximum and minimum room illuminance) for IBM flat panels. It also addresses the possible loss of contrast in medical images on flat panel displays because of the effect of nonlinearity in the dependence of luminance on room illuminance at low room lighting.

Influence of stimulus size on revealing non-cardinal color mechanisms.

PubMed

Gunther, Karen L; Downey, Colin O

2016-10-01

Multiple studies have shown that performance of subjects on a number of visual tasks is worse for non-cardinal than cardinal colors, especially in the red-green/luminance (RG/LUM) and tritan/luminance (TRIT/LUM) color planes. Inspired by neurophysiological evidence that suppressive surround input to receptive fields is particularly sensitive to luminance, we hypothesized that non-cardinal mechanisms in the RG/LUM and TRIT/LUM planes would be more sensitive to stimulus size than are isoluminant non-cardinal mechanisms. In Experiment 1 we tested 9-10 color-normal subjects in each of the three color planes (RG/TRIT, RG/LUM, and TRIT/LUM) on visual search at four bull's-eye dot sizes (0.5°/1°, 1°/2°, 2°/4°, and 3°/6° center/annulus dot diameter). This study yielded a significant main effect of dot size in each of the three color planes. In Experiment 2 we tested the same hypothesis using noise masking, at three stimulus sizes (3°, 6° and 9° diameter Gabors), again in all three color planes (5 subjects per color plane). This experiment yielded, in the RG/TRIT plane, a significant main effect of stimulus size; in the RG/LUM plane, significant evidence for non-cardinal mechanisms only for the 9° stimulus; but in the TRIT/LUM plane no evidence for non-cardinal mechanisms at any stimulus size. These results suggest that non-cardinal mechanisms, particularly in the RG/LUM color plane, are more sensitive to stimulus size than are non-cardinals in the RG/TRIT plane, supporting our hypothesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Oncogenic Role of RhoGAPs in Basal-Like Breast Cancer

DTIC Science & Technology

2015-02-01

cell lines, and mouse models . c) In vivo tumorigenesis and metastasis assays. Milestones: Identify whether ArhGAP11A and RacGAP1 can promote tumor growth...also upregulated in basal (C3(I)-Tag) but not luminal (MMTV-Neu) genetically- engineered mouse models (Fig. 1B). At the protein level, RacGAP1 was...hypothesis that these RhoGAPs are indeed playing an oncogenic role in these cells. Human Tumors Mouse Model Tumors Normal Luminal A Basal-like Normal

Multifunctional Device based on phosphor-piezoelectric PZT: lighting, speaking, and mechanical energy harvesting.

PubMed

Lee, Sunghoon; Kang, Taewook; Lee, Wunho; Afandi, Mohammad M; Ryu, Jongho; Kim, Jongsu

2018-01-10

We demonstrated the tri-functional device based on all powder-processing methods by using ZnS powder as phosphor layer and piezoelectric material as dielectric layer. The fabricated device generated the electroluminescent (EL) light from phosphor and the sound from piezoelectric sheet under a supply of external electric power, and additionally harvested the reverse-piezoelectric energy to be converted into EL light. Under sinusoidal applied voltage, EL luminances were exponentially increased with a maximum luminous efficiency of 1.3 lm/W at 40 V and 1,000 Hz, and sound pressure levels (SPLs) were linearly increased. The EL luminances were linearly dependent on applied frequency while the SPLs showed the parabolic increase behavior below 1,000 Hz and then the flat response. The temperature dependence on EL luminances and SPLs was demonstrated; the former was drastically increased and the latter was slightly decreased with the increase of temperature. Finally, as an energy harvesting application, the piezoelectric-induced electroluminescence effect was demonstrated by applying only mechanical pressure to the device without any external electric power.

Demonstration of intermediate cells during human prostate epithelial differentiation in situ and in vitro using triple-staining confocal scanning microscopy.

PubMed

van Leenders, G; Dijkman, H; Hulsbergen-van de Kaa, C; Ruiter, D; Schalken, J

2000-08-01

In human prostate epithelium, morphologically basal and luminal cells can be discriminated. The basal cell layer that putatively contains progenitor cells of the secretory epithelium is characterized by the expression of keratins (K) 5 and 14. Luminal cells represent the secretory compartment of the epithelium and express K8 and 18. We developed a technique for the simultaneous analysis of K5, 14, and 18 to identify intermediate cell stages in the prostate epithelium and to study the dynamic aspects of its differentiation in vitro. Nonmalignant prostate tissue and primary epithelial cultures were immunohistochemically characterized using triple staining with antibodies for K5, K14, and K18. Antibodies for K18 and K5 were conjugated directly with fluorochromes Alexa 488 and 546. K14 was visualized indirectly with streptavidin-Cy5. Keratin expression was analyzed by confocal scanning microscopy. The occurrence of exocrine and neuroendocrine differentiation in culture was determined via antibodies to prostate-specific antigen (PSA), chromogranin A, and serotonin. We found that basal cells expressed either K5(++)/14(++)/18+ or K5(++)/18+. The majority of luminal cells expressed K18(++), but colocalization of K5+/18(++) were recognized. Epithelial monolayer cultures predominantly revealed the basal cell phenotype K5(++)/14(++)/18+, whereas intermediate subpopulations expressing K5+/14+/18(++) and K5+/18(++) were also identified. On confluence, differentiation was induced as multicellular gland-like buds, and extensions became evident on top of the monolayer. These structures were composed of K18(++)- and K5+/18(+)-positive cell clusters surrounded by phenotypically basal cells. Few multicellular structures and cells in the monolayer showed exocrine differentiation (PSA+), but expression of chromogranin A and serotonin was absent. We conclude that simultaneous evaluation of keratin expression is useful for analyzing epithelial differentiation in the prostate. During this process, putative stem cells phenotypically resembling K5(++)/14(++)/18+ differentiate toward luminal cells (K18(++)) via intermediate cell stages, as identified by up-regulation of K18 and down-regulation of K5 and 14.

Cell-specific effects of luminal acid, bicarbonate, cAMP, and carbachol on transporter trafficking in the intestine

PubMed Central

Jakab, Robert L.; Collaco, Anne M.

2012-01-01

Changes in intestinal luminal pH affect mucosal ion transport. The aim of this study was to compare how luminal pH and specific second messengers modulate the membrane traffic of four major ion transporters (CFTR, NHE3, NKCC1, and NBCe1) in rat small intestine. Ligated duodenal, jejunal, and ileal segments were infused with acidic or alkaline saline, 8-Br-cAMP, or the calcium agonist carbachol in vivo for 20 min. Compared with untreated intestine, lumen pH was reduced after cAMP or carbachol and increased following HCO3−-saline. Following HCl-saline, lumen pH was restored to control pH levels. All four secretory stimuli resulted in brush-border membrane (BBM) recruitment of CFTR in crypts and villi. In villus enterocytes, CFTR recruitment was coincident with internalization of BBM NHE3 and basolateral membrane recruitment of the bicarbonate transporter NBCe1. Both cAMP and carbachol recruited NKCC1 to the basolateral membrane of enterocytes, while luminal acid or HCO3− retained NKCC1 in intracellular vesicles. Luminal acid resulted in robust recruitment of CFTR and NBCe1 to their respective enterocyte membrane domains in the upper third of the villi; luminal HCO3− induced similar membrane changes lower in the villi. These findings indicate that each stimulus promotes a specific transporter trafficking response along the crypt-villus axis. This is the first demonstration that physiologically relevant secretory stimuli exert their actions in villus enterocytes by membrane recruitment of CFTR and NBCe1 in tandem with NHE3 internalization. PMID:22936272

Cell-specific effects of luminal acid, bicarbonate, cAMP, and carbachol on transporter trafficking in the intestine.

PubMed

Jakab, Robert L; Collaco, Anne M; Ameen, Nadia A

2012-10-15

Changes in intestinal luminal pH affect mucosal ion transport. The aim of this study was to compare how luminal pH and specific second messengers modulate the membrane traffic of four major ion transporters (CFTR, NHE3, NKCC1, and NBCe1) in rat small intestine. Ligated duodenal, jejunal, and ileal segments were infused with acidic or alkaline saline, 8-Br-cAMP, or the calcium agonist carbachol in vivo for 20 min. Compared with untreated intestine, lumen pH was reduced after cAMP or carbachol and increased following HCO(3)(-)-saline. Following HCl-saline, lumen pH was restored to control pH levels. All four secretory stimuli resulted in brush-border membrane (BBM) recruitment of CFTR in crypts and villi. In villus enterocytes, CFTR recruitment was coincident with internalization of BBM NHE3 and basolateral membrane recruitment of the bicarbonate transporter NBCe1. Both cAMP and carbachol recruited NKCC1 to the basolateral membrane of enterocytes, while luminal acid or HCO(3)(-) retained NKCC1 in intracellular vesicles. Luminal acid resulted in robust recruitment of CFTR and NBCe1 to their respective enterocyte membrane domains in the upper third of the villi; luminal HCO(3)(-) induced similar membrane changes lower in the villi. These findings indicate that each stimulus promotes a specific transporter trafficking response along the crypt-villus axis. This is the first demonstration that physiologically relevant secretory stimuli exert their actions in villus enterocytes by membrane recruitment of CFTR and NBCe1 in tandem with NHE3 internalization.

Role of microRNA221 in regulating normal mammary epithelial hierarchy and breast cancer stem-like cells.

PubMed

Ke, Jia; Zhao, Zhiju; Hong, Su-Hyung; Bai, Shoumin; He, Zhen; Malik, Fayaz; Xu, Jiahui; Zhou, Lei; Chen, Weilong; Martin-Trevino, Rachel; Wu, Xiaojian; Lan, Ping; Yi, Yongju; Ginestier, Christophe; Ibarra, Ingrid; Shang, Li; McDermott, Sean; Luther, Tahra; Clouthier, Shawn G; Wicha, Max S; Liu, Suling

2015-02-28

Increasing evidence suggests that lineage specific subpopulations and stem-like cells exist in normal and malignant breast tissues. Epigenetic mechanisms maintaining this hierarchical homeostasis remain to be investigated. In this study, we found the level of microRNA221 (miR-221) was higher in stem-like and myoepithelial cells than in luminal cells isolated from normal and malignant breast tissue. In normal breast cells, over-expression of miR-221 generated more myoepithelial cells whereas knock-down of miR-221 increased luminal cells. Over-expression of miR-221 stimulated stem-like cells in luminal type of cancer and the miR-221 level was correlated with clinical outcome in breast cancer patients. Epithelial-mesenchymal transition (EMT) was induced by overexpression of miR-221 in normal and breast cancer cells. The EMT related gene ATXN1 was found to be a miR-221 target gene regulating breast cell hierarchy. In conclusion, we propose that miR-221 contributes to lineage homeostasis of normal and malignant breast epithelium.

Quantifying the effect of colorization enhancement on mammogram images

NASA Astrophysics Data System (ADS)

Wojnicki, Paul J.; Uyeda, Elizabeth; Micheli-Tzanakou, Evangelia

2002-04-01

Current methods of radiological displays provide only grayscale images of mammograms. The limitation of the image space to grayscale provides only luminance differences and textures as cues for object recognition within the image. However, color can be an important and significant cue in the detection of shapes and objects. Increasing detection ability allows the radiologist to interpret the images in more detail, improving object recognition and diagnostic accuracy. Color detection experiments using our stimulus system, have demonstrated that an observer can only detect an average of 140 levels of grayscale. An optimally colorized image can allow a user to distinguish 250 - 1000 different levels, hence increasing potential image feature detection by 2-7 times. By implementing a colorization map, which follows the luminance map of the original grayscale images, the luminance profile is preserved and color is isolated as the enhancement mechanism. The effect of this enhancement mechanism on the shape, frequency composition and statistical characteristics of the Visual Evoked Potential (VEP) are analyzed and presented. Thus, the effectiveness of the image colorization is measured quantitatively using the Visual Evoked Potential (VEP).

Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality.

PubMed

Xu, Renfeng; Wang, Huachun; Thibos, Larry N; Bradley, Arthur

2017-04-01

Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1  cd/m², and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5  cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving defocused image quality remain throughout the photopic and mesopic ranges. However, restricting pupils to <2  mm will cause significant reductions in the best focus vision at low photopic and mesopic luminances.

How much crosstalk can be allowed in a stereoscopic system at various grey levels?

NASA Astrophysics Data System (ADS)

Shestak, Sergey; Kim, Daesik; Kim, Yongie

2012-03-01

We have calculated a perceptual threshold of stereoscopic crosstalk on the basis of mathematical model of human vision sensitivity. Instead of linear model of just noticeable difference (JND) known as Weber's law we applied nonlinear Barten's model. The predicted crosstalk threshold varies with the background luminance. The calculated values of threshold are in a reasonable agreement with known experimental data. We calculated perceptual threshold of crosstalk for various combinations of the applied grey level. This result can be applied for the assessment of grey-to-grey crosstalk compensation. Further computational analysis of the applied model predicts the increase of the displayable image contrast with reduction of the maximum displayable luminance.

Boosting jet power in black hole spacetimes.

PubMed

Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis

2011-08-02

The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

Magnetic resonance metabolic profiling of estrogen receptor-positive breast cancer: correlation with currently used molecular markers

PubMed Central

Koo, Ja Seung; Kim, Siwon; Park, Vivian Youngjean; Kim, Eun-Kyung; Kim, Suhkmann; Kim, Min Jung

2017-01-01

Estrogen receptor (ER)-positive breast cancers overall have a good prognosis, however, some patients suffer relapses and do not respond to endocrine therapy. The purpose of this study was to determine whether there are any correlations between high-resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) metabolic profiles of core needle biopsy (CNB) specimens and the molecular markers currently used in patients with ER-positive breast cancers. The metabolic profiling of CNB samples from 62 ER-positive cancers was performed by HR-MAS MRS. Metabolic profiles were compared according to human epidermal growth factor receptor 2 (HER2) and Ki-67 status, and luminal type, using the Mann-Whitney test. Multivariate analysis was performed with orthogonal projections to latent structure-discriminant analysis (OPLS-DA). In univariate analysis, the HER2-positive group was shown to have higher levels of glycine and glutamate, compared to the HER2-negative group (P<0.01, and P <0.01, respectively). The high Ki-67 group showed higher levels of glutamate than the low Ki-67 group without statistical significance. Luminal B cancers showed higher levels of glycine (P=0.01) than luminal A cancers. In multivariate analysis, the OPLS-DA models built with HR-MAS MR metabolic profiles showed visible discrimination between the subgroups according to HER2 and Ki-67 status, and luminal type. This study showed that the metabolic profiles of CNB samples assessed by HR-MAS MRS can be used to detect potential prognostic biomarkers as well as to understand the difference in metabolic mechanism among subtypes of ER-positive breast cancer. PMID:28969000

Luminance level of a monitor: influence on detectability and detection rate of breast cancer in 2D mammography

NASA Astrophysics Data System (ADS)

Bemelmans, Frédéric; Rashidnasab, Alaleh; Chesterman, Frédérique; Kimpe, Tom; Bosmans, Hilde

2016-03-01

Purpose: To evaluate lesion detectability and reading time as a function of luminance level of the monitor. Material and Methods: 3D mass models and microcalcification clusters were simulated into ROIs of for processing mammograms. Randomly selected ROIs were subdivided in three groups according to their background glandularity: high (>30%), medium (15-30%) and low (<15%). 6 non-spiculated masses (9 - 11mm), 6 spiculated masses (5 - 7mm) and 6 microcalcification clusters (2 - 4mm) were scaled in 3D to create a range of sizes. The linear attenuation coefficient (AC) of the masses was adjusted from 100% glandular tissue to 90%, 80%, 70%, to create different contrasts. Six physicists read the full database on Barco's Coronis Uniti monitor for four different luminance levels (300, 800, 1000 and 1200 Cd/m2), using a 4-AFC tool. Percentage correct (PC) and time were computed for all different conditions. A paired t-test was performed to evaluate the effect of luminance on PC and time. A multi-factorial analysis was performed using MANOVA.. Results: Paired t-test indicated a statistically significant difference for the average time per session between 300 and 1200; 800 and 1200; 1000 and 1200 Cd/m2, for all participants combined. There was no effect on PC. MANOVA denoted significantly lower reading times for high glandularity images at 1200 Cd/m2. Both types of masses were significantly faster detected at 1200 Cd/m2, for the contrast study. In the size study, microcalcification clusters and spiculated masses had a significantly higher detection rate at 1200 Cd/m2. Conclusion: These results demonstrate a significant decrease in reading time, while detectability remained constant.

MCM2: An alternative to Ki-67 for measuring breast cancer cell proliferation.

PubMed

Yousef, Einas M; Furrer, Daniela; Laperriere, David L; Tahir, Muhammad R; Mader, Sylvie; Diorio, Caroline; Gaboury, Louis A

2017-05-01

Breast cancer is a heterogeneous disease comprising a diversity of tumor subtypes that manifest themselves in a wide variety of clinical, pathological, and molecular features. One important subset, luminal breast cancers, comprises two clinically distinct subtypes luminal A and B each of them endowed with its own genetic program of differentiation and proliferation. Luminal breast cancers were operationally defined as follows: Luminal A: ER+, PR+, HER2-, Ki-67<14% and Luminal B: ER+ and/or PR+, HER2-,Ki-67≥14% or, alternatively ER+ and/or PR+, HER2+, any Ki-67. There is currently a need for a clinically robust and validated immunohistochemical assay that can help distinguish between luminal A and B breast cancer. MCM2 is a family member of the minichromosome maintenance protein complex whose role in DNA replication and cell proliferation is firmly established. As MCM2 appears to be an attractive alternative to Ki-67, we sought to study the expression of MCM2 and Ki-67 in different histological grades and molecular subtypes of breast cancer focusing primarily on ER-positive tumors. MCM2 and Ki-67 mRNA expression were studied using in silico analysis of available DNA microarray and RNA-sequencing data of human breast cancer. We next used immunohistochemistry to evaluate protein expression of MCM2 and Ki-67 on tissue microarrays of invasive breast carcinoma. We found that MCM2 and Ki-67 are highly expressed in breast tumors of high histological grades, comprising clinically aggressive tumors such as triple-negative, HER2-positive and luminal B subtypes. MCM2 expression was detected at higher levels than that of Ki-67 in normal breast tissues and in breast cancers. The bimodal distribution of MCM2 scores in ER+/HER2- breast tumors led to the identification of two distinct subgroups with different relapse-free survival rates. In conclusion, MCM2 expression can help sorting out two clinically important subsets of luminal breast cancer whose treatment and clinical outcomes are likely to diverge.

Evaluation of tablet computers for visual function assessment.

PubMed

Bodduluri, Lakshmi; Boon, Mei Ying; Dain, Stephen J

2017-04-01

Recent advances in technology and the increased use of tablet computers for mobile health applications such as vision testing necessitate an understanding of the behavior of the displays of such devices, to facilitate the reproduction of existing or the development of new vision assessment tests. The purpose of this study was to investigate the physical characteristics of one model of tablet computer (iPad mini Retina display) with regard to display consistency across a set of devices (15) and their potential application as clinical vision assessment tools. Once the tablet computer was switched on, it required about 13 min to reach luminance stability, while chromaticity remained constant. The luminance output of the device remained stable until a battery level of 5%. Luminance varied from center to peripheral locations of the display and with viewing angle, whereas the chromaticity did not vary. A minimal (1%) variation in luminance was observed due to temperature, and once again chromaticity remained constant. Also, these devices showed good temporal stability of luminance and chromaticity. All 15 tablet computers showed gamma functions approximating the standard gamma (2.20) and showed similar color gamut sizes, except for the blue primary, which displayed minimal variations. The physical characteristics across the 15 devices were similar and are known, thereby facilitating the use of this model of tablet computer as visual stimulus displays.

Evaluation of visual acuity with Gen 3 night vision goggles

NASA Technical Reports Server (NTRS)

Bradley, Arthur; Kaiser, Mary K.

1994-01-01

Using laboratory simulations, visual performance was measured at luminance and night vision imaging system (NVIS) radiance levels typically encountered in the natural nocturnal environment. Comparisons were made between visual performance with unaided vision and that observed with subjects using image intensification. An Amplified Night Vision Imaging System (ANVIS6) binocular image intensifier was used. Light levels available in the experiments (using video display technology and filters) were matched to those of reflecting objects illuminated by representative night-sky conditions (e.g., full moon, starlight). Results show that as expected, the precipitous decline in foveal acuity experienced with decreasing mesopic luminance levels is effectively shifted to much lower light levels by use of an image intensification system. The benefits of intensification are most pronounced foveally, but still observable at 20 deg eccentricity. Binocularity provides a small improvement in visual acuity under both intensified and unintensified conditions.

Regulation of Bicarbonate Secretion in Marine Fish Intestine by the Calcium-Sensing Receptor.

PubMed

Gregório, Sílvia F; Fuentes, Juan

2018-04-04

In marine fish, high epithelial intestinal HCO₃ − secretion generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. The present study was designed to expose the putative role for calcium and the calcium-sensing receptor (CaSR) in the regulation of HCO₃ − secretion in the intestine of the sea bream ( Sparus aurata L.). Effects on the expression of the CaSR in the intestine were evaluated by qPCR and an increase was observed in the anterior intestine in fed fish compared with unfed fish and with different regions of intestine. CaSR expression reflected intestinal fluid calcium concentration. In addition, anterior intestine tissue was mounted in Ussing chambers to test the putative regulation of HCO₃ − secretion in vitro using the anterior intestine. HCO₃ − secretion was sensitive to varying calcium levels in luminal saline and to calcimimetic compounds known to activate/block the CaSR i.e., R 568 and NPS-2143. Subsequent experiments were performed in intestinal sacs to measure water absorption and the sensitivity of water absorption to varying luminal levels of calcium and calcimimetics were exposed as well. It appears, that CaSR mediates HCO₃ − secretion and water absorption in marine fish as shown by responsiveness to calcium levels and calcimimetic compounds.

A new approach to modeling the influence of image features on fixation selection in scenes

PubMed Central

Nuthmann, Antje; Einhäuser, Wolfgang

2015-01-01

Which image characteristics predict where people fixate when memorizing natural images? To answer this question, we introduce a new analysis approach that combines a novel scene-patch analysis with generalized linear mixed models (GLMMs). Our method allows for (1) directly describing the relationship between continuous feature value and fixation probability, and (2) assessing each feature's unique contribution to fixation selection. To demonstrate this method, we estimated the relative contribution of various image features to fixation selection: luminance and luminance contrast (low-level features); edge density (a mid-level feature); visual clutter and image segmentation to approximate local object density in the scene (higher-level features). An additional predictor captured the central bias of fixation. The GLMM results revealed that edge density, clutter, and the number of homogenous segments in a patch can independently predict whether image patches are fixated or not. Importantly, neither luminance nor contrast had an independent effect above and beyond what could be accounted for by the other predictors. Since the parcellation of the scene and the selection of features can be tailored to the specific research question, our approach allows for assessing the interplay of various factors relevant for fixation selection in scenes in a powerful and flexible manner. PMID:25752239

Receiver operating characteristic analysis. Application to the study of quantum fluctuation effects in optic nerve of Rana pipiens

PubMed Central

1975-01-01

Receiver operating characteristic (ROC) analysis of nerve messages is described. The hypothesis that quantum fluctuations provide the only limit to the ability of frog ganglion cells to signal luminance change information is examined using ROC analysis. In the context of ROC analysis, the quantum fluctuation hypothesis predicts (a) the detectability of a luminance change signal should rise proportionally to the size of the change, (b) detectability should decrease as the square root of background, an implication of which is the deVries-Rose law, and (c) ROC curves should exhibit a shape particular to underlying Poisson distributions. Each of these predictions is confirmed for the responses of dimming ganglion cells to brief luminance decrements at scotopic levels, but none could have been tested using classical nerve message analysis procedures. PMID:172597

Detection of Lysosomal Exocytosis by Surface Exposure of Lamp1 Luminal Epitopes.

PubMed

Andrews, Norma W

2017-01-01

Elevation in the cytosolic Ca 2+ concentration triggers exocytosis of lysosomes in many cell types. This chapter describes a method to detect lysosomal exocytosis in mammalian cells, which takes advantage of the presence of an abundant glycoprotein, Lamp1, on the membrane of lysosomes. Lamp1 is a transmembrane protein with a large, heavily glycosylated region that faces the lumen of lysosomes. When lysosomes fuse with the plasma membrane, epitopes present on the luminal domain of Lamp1 are exposed on the cell surface. The Lamp1 luminal epitopes can then be detected on the surface of live, unfixed cells using highly specific monoclonal antibodies and fluorescence microscopy. The main advantage of this method is its sensitivity, and the fact that it provides spatial information on lysosomal exocytosis at the single cell level.

Effect of contiguity and figure-ground organization on the area rule of lightness.

PubMed

Boyaci, Huseyin; Simşek, Mahru Kobal; Subaşı, Ece

2014-11-25

In a simple two-dimensional (2D) display composed of two uniform surfaces with different luminances, the lightness of the darker surface varies as a function of its relative area while its luminance is held constant (Gilchrist & Radonjić, 2009; Li & Gilchrist, 1999). This phenomenon is known as the area rule of lightness, and although it is extensively studied in the literature, the underlying principles are still largely unknown. Here, using computer-generated stimuli, we investigated the effects of contiguity and figure-ground organization on the area rule of lightness. Stimuli were 2D disks composed of radial sectors with high (25 cd/m2) or low (8 cd/m2) luminance. On each trial, observers judged the lightness of the sectors by adjusting the luminance of a matching patch. Four conditions were tested. In the contiguous condition, there were one dark and one light sector; in the noncontiguous condition, both the light and dark surfaces were split into four equal radial sectors. Figure and ground conditions were generated by adding small contextual elements to the stimulus. We found that the area rule applied under all conditions; however, the functional form of the effect showed marked differences across conditions. Taken together, our results show that both high-level (e.g., perceptual grouping, figure-ground organization) and low-level (e.g., spatial-summation) mechanisms play a role in the area rule of lightness. © 2014 ARVO.

Conditionally reprogrammed normal and primary tumor prostate epithelial cells: a novel patient-derived cell model for studies of human prostate cancer

PubMed Central

Timofeeva, Olga A.; Palechor-Ceron, Nancy; Li, Guanglei; Yuan, Hang; Krawczyk, Ewa; Zhong, Xiaogang; Liu, Geng; Upadhyay, Geeta; Dakic, Aleksandra; Yu, Songtao; Fang, Shuang; Choudhury, Sujata; Zhang, Xueping; Ju, Andrew; Lee, Myeong-Seon; Dan, Han C.; Ji, Youngmi; Hou, Yong; Zheng, Yun-Ling; Albanese, Chris; Rhim, Johng; Schlegel, Richard; Dritschilo, Anatoly; Liu, Xuefeng

2017-01-01

Our previous study demonstrated that conditional reprogramming (CR) allows the establishment of patient-derived normal and tumor epithelial cell cultures from a variety of tissue types including breast, lung, colon and prostate. Using CR, we have established matched normal and tumor cultures, GUMC-29 and GUMC-30 respectively, from a patient's prostatectomy specimen. These CR cells proliferate indefinitely in vitro and retain stable karyotypes. Most importantly, only tumor-derived CR cells (GUMC-30) produced tumors in xenografted SCID mice, demonstrating maintenance of the critical tumor phenotype. Characterization of cells with DNA fingerprinting demonstrated identical patterns in normal and tumor CR cells as well as in xenografted tumors. By flow cytometry, both normal and tumor CR cells expressed basal, luminal, and stem cell markers, with the majority of the normal and tumor CR cells expressing prostate basal cell markers, CD44 and Trop2, as well as luminal marker, CD13, suggesting a transit-amplifying phenotype. Consistent with this phenotype, real time RT-PCR analyses demonstrated that CR cells predominantly expressed high levels of basal cell markers (KRT5, KRT14 and p63), and low levels of luminal markers. When the CR tumor cells were injected into SCID mice, the expression of luminal markers (AR, NKX3.1) increased significantly, while basal cell markers dramatically decreased. These data suggest that CR cells maintain high levels of proliferation and low levels of differentiation in the presence of feeder cells and ROCK inhibitor, but undergo differentiation once injected into SCID mice. Genomic analyses, including SNP and INDEL, identified genes mutated in tumor cells, including components of apoptosis, cell attachment, and hypoxia pathways. The use of matched patient-derived cells provides a unique in vitro model for studies of early prostate cancer. PMID:28009986

Resolution and Kinematics of Molecular Gas Surrounding the Cloverleaf Quasar at Z = 2.6 Using the Gravitational Lens

NASA Astrophysics Data System (ADS)

Yun, M. S.; Scoville, N. Z.; Carrasco, J. J.; Blandford, R. D.

1997-04-01

Gravitational lenses have long been advertised as primitive telescopes, capable of magnifying cosmologically distant sources. In this Letter we present new, 0.9" resolution CO (7-6) observations of the z = 2.56 Cloverleaf quasar (H1413+117) and spatially resolved images. By modeling the gravitational lens, we infer a size scale of 0.3" (~1 kpc) for the molecular gas structure surrounding the quasar, and the gas has a kinematic structure roughly consistent with a rotating disk. The observed properties of the CO-emitting gas are similar to the nuclear starburst complexes found in the infrared luminous galaxies in the local universe, and metal enrichment by vigorous star formation within this massive nuclear gas complex can explain the abundance of carbon and oxygen in the interstellar medium of this system observed when the universe was only a few billion years old. Obtaining corresponding details in an unlensed object at similar distances would be well beyond the reach of current instruments, and this study highlights the less exploited yet powerful use of a gravitational lens as a natural telescope.

AGN radiative feedback in dusty quasar populations

NASA Astrophysics Data System (ADS)

Ishibashi, W.; Banerji, M.; Fabian, A. C.

2017-08-01

New populations of hyper-luminous, dust-obscured quasars have been recently discovered around the peak epoch of galaxy formation (z ˜ 2-3), in addition to similar sources found at lower redshifts. Such dusty quasars are often interpreted as sources 'in transition', from dust-enshrouded starbursts to unobscured luminous quasars, along the evolutionary sequence. Here we consider the role of the active galactic nucleus (AGN) radiative feedback, driven by radiation pressure on dust, in high-luminosity, dust-obscured sources. We analyse how the radiation pressure-driven dusty shell models, with different shell mass configurations, may be applied to the different populations of dusty quasars reported in recent observations. We find that expanding shells, sweeping up matter from the surrounding environment, may account for prolonged obscuration in dusty quasars, e.g. for a central luminosity of L ˜ 1047 erg s-1, a typical obscured phase (with extinction in the range AV ˜ 1-10 mag) may last a few ˜106 yr. On the other hand, fixed-mass shells, coupled with high dust-to-gas ratios, may explain the extreme outflows recently discovered in red quasars at high redshifts. We discuss how the interaction between AGN radiative feedback and the ambient medium at different temporal stages in the evolutionary sequence may contribute to shape the observational appearance of dusty quasar populations.

Measuring the ISM Content of Optically Luminous Type 2 Quasars

NASA Astrophysics Data System (ADS)

Marshall, Jameeka; Petric, Andreea; Flagey, Nicolas; Lacy, Mark; Omont, Alain

2018-01-01

There is a connection between black holes (BH) and the surrounding bulge stars. Measuring the cold interstellar medium (ISM) content of host galaxies is essential to understand the coevolution of galaxies and BHs. The ISM measurement is important because gas constitutes the raw material from which BHs grow and stars form. Quasars are extremely luminous active galaxies fueled by accreting supermassive black holes. Type 2 quasars have narrow spectral lines whereas type 1 quasars have broad spectral lines. Not only can the ISM measurements provide empirical data to help further clarify quasar models but it is also crucial in distinguishing the physical differences between type 1 and type 2 quasars. Observations of twenty type 2 quasars were made using IRAM, a single dish 30 meter radio telescope, to measure 12CO (1-0) and 12CO (2-1) emission. We used line widths to constrain the dynamical mass and gravitational potential of the host galaxy. Star formation rate (SFR) measured in the infrared (IR) and SFR derived from optical spectra were used to estimate star formation efficiency and gas depletion time scale (M H2/star formation rate). Preliminary analysis suggests that star formation efficiency in type 2 quasars is slightly higher than in type 1 quasars.

Bioluminescent symbionts of flashlight fishes and deep-sea anglerfishes form unique lineages related to the genus Vibrio.

PubMed

Haygood, M G; Distel, D L

1993-05-13

Bioluminescent symbioses range from facultative associations to highly adapted, apparently obligate ones. The family Anomalopidae (flashlight fishes) encompasses five genera of tropical reef fishes that have large suborbital light organs. The suborder Ceratioidei (deep-sea anglerfishes) contains 11 families. In nine of these, females have a bioluminescent lure that contains bacterial symbionts. In all other fish light-organ symbioses (occurring in 10 families in 5 orders), the symbionts belong to three Photobacterium species; nonsymbiotic luminous bacteria are Vibrio species. The bacteria are extracellular and tightly packed in tubules that communicate with the exterior, releasing bacteria into the gut of the host or the surrounding sea water. The released bacteria are usually cultivable and can contribute to planktonic populations. Although anomalopids release bacteria and ceratioids have pores that would allow release, the fate of these bacteria is unknown and they cannot be cultured by standard isolation techniques. We report here phylogenetic analysis of 16S ribosomal RNA gene sequences from light organs that show that anomalopid and ceratioid symbionts are not known luminous bacteria, but are new groups related to Vibrio spp. They are characterized by host specificity, deep divergence between symbionts from different genera (anomalopids) or families (ceratioids) and, possibly, parallel divergence of hosts and symbionts.

bc-GenExMiner 3.0: new mining module computes breast cancer gene expression correlation analyses.

PubMed

Jézéquel, Pascal; Frénel, Jean-Sébastien; Campion, Loïc; Guérin-Charbonnel, Catherine; Gouraud, Wilfried; Ricolleau, Gabriel; Campone, Mario

2013-01-01

We recently developed a user-friendly web-based application called bc-GenExMiner (http://bcgenex.centregauducheau.fr), which offered the possibility to evaluate prognostic informativity of genes in breast cancer by means of a 'prognostic module'. In this study, we develop a new module called 'correlation module', which includes three kinds of gene expression correlation analyses. The first one computes correlation coefficient between 2 or more (up to 10) chosen genes. The second one produces two lists of genes that are most correlated (positively and negatively) to a 'tested' gene. A gene ontology (GO) mining function is also proposed to explore GO 'biological process', 'molecular function' and 'cellular component' terms enrichment for the output lists of most correlated genes. The third one explores gene expression correlation between the 15 telomeric and 15 centromeric genes surrounding a 'tested' gene. These correlation analyses can be performed in different groups of patients: all patients (without any subtyping), in molecular subtypes (basal-like, HER2+, luminal A and luminal B) and according to oestrogen receptor status. Validation tests based on published data showed that these automatized analyses lead to results consistent with studies' conclusions. In brief, this new module has been developed to help basic researchers explore molecular mechanisms of breast cancer. DATABASE URL: http://bcgenex.centregauducheau.fr

Tumor Metabolism and Blood Flow as Assessed by PET Varies by Tumor Subtype in Locally Advanced Breast Cancer

PubMed Central

Specht, Jennifer M.; Kurland, Brenda F.; Montgomery, Susan K.; Dunnwald, Lisa K.; Doot, Robert K.; Gralow, Julie R.; Ellis, Georgina K.; Linden, Hannah M.; Livingston, Robert B.; Allison, Kimberly H.; Schubert, Erin K.; Mankoff, David A.

2010-01-01

Purpose Dynamic PET imaging can identify patterns of breast cancer metabolism and perfusion in patients receiving neoadjuvant chemotherapy (NC) that are predictive of response. This analysis examines tumor metabolism and perfusion by tumor subtype. Experimental Design Tumor subtype was defined by immunohistochemistry (IHC) in 71 patients with LABC undergoing NC. Subtype was defined as luminal (ER/PR positive), triple-negative (TN; ER/PR negative, HER2 negative) and HER2 (ER/PR negative, HER2 over-expressing). Metabolic rate (MRFDG) and blood flow (BF) were calculated from PET imaging prior to NC. Pathologic complete response (pCR) to NC was classified as pCR versus other. Results Twenty-five (35%) of 71 patients had TN tumors, 6 (8%) were HER2 and 40 (56%) were luminal. MRFDG for TN tumors was on average 67% greater than for luminal tumors (95% CI 9% – 156%), and average MRFDG/BF ratio was 53% greater in TN compared to luminal tumors (95% CI 9% – 114%) (p < 0.05 for both). Average blood flow levels did not differ by subtype (p = 0.73). Most luminal tumors showed relatively low MRFDG and BF (and did not achieve pCR); high MRFDG was generally matched with high BF in luminal tumors, and predicted pCR. This was not true in TN tumors. Conclusions The relationship between breast tumor metabolism and perfusion differed by subtype. The high MRFDG/BF ratio that predicts poor response to NC was more common in TN tumors. Metabolism and perfusion measures may identify subsets of tumors susceptible and resistant to NC and may help direct targeted therapy. PMID:20460489

Representation of Perceptual Color Space in Macaque Posterior Inferior Temporal Cortex (the V4 Complex)

PubMed Central

Bohon, Kaitlin S.; Hermann, Katherine L.; Hansen, Thorsten

2016-01-01

Abstract The lateral geniculate nucleus is thought to represent color using two populations of cone-opponent neurons [L vs M; S vs (L + M)], which establish the cardinal directions in color space (reddish vs cyan; lavender vs lime). How is this representation transformed to bring about color perception? Prior work implicates populations of glob cells in posterior inferior temporal cortex (PIT; the V4 complex), but the correspondence between the neural representation of color in PIT/V4 complex and the organization of perceptual color space is unclear. We compared color-tuning data for populations of glob cells and interglob cells to predictions obtained using models that varied in the color-tuning narrowness of the cells, and the color preference distribution across the populations. Glob cells were best accounted for by simulated neurons that have nonlinear (narrow) tuning and, as a population, represent a color space designed to be perceptually uniform (CIELUV). Multidimensional scaling and representational similarity analyses showed that the color space representations in both glob and interglob populations were correlated with the organization of CIELUV space, but glob cells showed a stronger correlation. Hue could be classified invariant to luminance with high accuracy given glob responses and above-chance accuracy given interglob responses. Luminance could be read out invariant to changes in hue in both populations, but interglob cells tended to prefer stimuli having luminance contrast, regardless of hue, whereas glob cells typically retained hue tuning as luminance contrast was modulated. The combined luminance/hue sensitivity of glob cells is predicted for neurons that can distinguish two colors of the same hue at different luminance levels (orange/brown). PMID:27595132

Night vision in barn owls: visual acuity and contrast sensitivity under dark adaptation.

PubMed

Orlowski, Julius; Harmening, Wolf; Wagner, Hermann

2012-12-06

Barn owls are effective nocturnal predators. We tested their visual performance at low light levels and determined visual acuity and contrast sensitivity of three barn owls by their behavior at stimulus luminances ranging from photopic to fully scotopic levels (23.5 to 1.5 × 10⁻⁶). Contrast sensitivity and visual acuity decreased only slightly from photopic to scotopic conditions. Peak grating acuity was at mesopic (4 × 10⁻² cd/m²) conditions. Barn owls retained a quarter of their maximal acuity when luminance decreased by 5.5 log units. We argue that the visual system of barn owls is designed to yield as much visual acuity under low light conditions as possible, thereby sacrificing resolution at photopic conditions.

Cryptic cuckoo eggs hide from competing cuckoos

PubMed Central

Gloag, Ros; Keller, Laurie-Anne; Langmore, Naomi E.

2014-01-01

Interspecific arms races between cuckoos and their hosts have produced remarkable examples of mimicry, with parasite eggs evolving to match host egg appearance and so evade removal by hosts. Certain bronze-cuckoo species, however, lay eggs that are cryptic rather than mimetic. These eggs are coated in a low luminance pigment that camouflages them within the dark interiors of hosts' nests. We investigated whether cuckoo egg crypsis is likely to have arisen from the same coevolutionary processes known to favour egg mimicry. We added high and low luminance-painted eggs to the nests of large-billed gerygones (Gerygone magnirostris), a host of the little bronze-cuckoo (Chalcites minutillus). Gerygones rarely rejected either egg type, and did not reject natural cuckoo eggs. Cuckoos, by contrast, regularly removed an egg from clutches before laying their own and were five times more likely to remove a high luminance model than its low luminance counterpart. Given that we found one-third of all parasitized nests were exploited by multiple cuckoos, our results suggest that competition between cuckoos has been the key selective agent for egg crypsis. In such intraspecific arms races, crypsis may be favoured over mimicry because it can reduce the risk of egg removal to levels below chance. PMID:25122227

Clinicopathological predictors of long-term benefit in breast cancer treated with neoadjuvant chemotherapy

PubMed Central

Galvez, Marco; Castaneda, Carlos A; Sanchez, Joselyn; Castillo, Miluska; Rebaza, Lia Pamela; Calderon, Gabriela; Cruz, Miguel De La; Cotrina, Jose Manuel; Abugattas, Julio; Dunstan, Jorge; Guerra, Henry; Mejia, Omar; Gomez, Henry L

2018-01-01

AIM To investigate the survival impact of clinicopathological factors, including pathological complete response (pCR) and tumor-infiltrating lymphocytes (sTIL) levels according to subtypes, in breast cancer (BC) patients who received neo-adjuvant chemotherapy (NAC). METHODS We evaluated 435 BC patients who presented and received NAC at the Instituto Nacional de Enfermedades Neoplasicas from 2003 to 2014. sTIL was analyzed as the proportion of tumor stroma occupied by lymphocytes, and was prospectively evaluated on hematoxylin and eosin-stained sections of the preNAC core biopsy. pCR was considered in the absence of infiltrating cancer cells in primary tumor and axillary lymph nodes. Analysis of statistical association between clinical pathological features, sTIL, pCR and survival were carried out using SPSSvs19. RESULTS Median age was 49 years (range 24-84 years) and the most frequent clinical stage was IIIB (58.3%). Luminal A, Luminal B, HER2-enriched and (triple-negative) TN phenotype was found in 24.6%, 37.9%, 17.7% and 19.8%, respectively. pCR was observed in 11% and median percentage of sTIL was 40% (2%-95%) in the whole population. pCR was associated to Ct1-2 (P = 0.045) and to high sTIL (P = 0.029) in the whole population. There was a slight trend towards significance for sTIL (P = 0.054) in Luminal A. sTIL was associated with grade III (P < 0.001), no-Luminal A subtype (P < 0.001), RE-negative (P < 0.001), PgR-negative (P < 0.001), HER2-positive (P = 0.002) and pCR (P = 0.029) in the whole population. Longer disease-free survival was associated with grade I-II (P = 0.006), cN0 (P < 0.001), clinical stage II (P = 0.004), ER-positive (P < 0.001), PgR-positive (P < 0.001), luminal A (P < 0.001) and pCR (P = 0.002). Longer disease-free survival was associated with grade I-II in Luminal A (P < 0.001), N0-1 in Luminal A (P = 0.045) and TNBC (P = 0.01), clinical stage II in Luminal A (P = 0.003) and TNBC (P = 0.038), and pCR in TNBC (P < 0.001). Longer overall survival was associated with grade I-II (P < 0.001), ER-positive (P < 0.001), PgR-positive (P < 0.001), Luminal A (P < 0.001), cN0 (P = 0.002) and pCR (P = 0.002) in the whole population. Overall survival was associated with clinical stage II (P = 0.017) in Luminal A, older age (P = 0.042) in Luminal B, and pCR in TNBC (P = 0.005). CONCLUSION Predictive and prognostic values of clinicopathological features, like pCR and sTIL, differ depending on the evaluated molecular subtype PMID:29651385

A novel type of transient luminous event produced by terrestrial gamma-ray flashes

NASA Astrophysics Data System (ADS)

Xu, Wei; Celestin, Sebastien; Pasko, Victor P.; Marshall, Robert A.

2017-03-01

Terrestrial Gamma-ray Flashes (TGFs), discovered in 1994 by the Compton Gamma-Ray Observatory, are high-energy photon bursts originating in the Earth's atmosphere in association with thunderstorms. In this paper, we demonstrate theoretically that, while TGFs pass through the atmosphere, the large quantities of energetic electrons knocked out by collisions between photons and air molecules generate excited species of neutral and ionized molecules, leading to a significant amount of optical emissions. These emissions represent a novel type of transient luminous events in the vicinity of the cloud tops. We show that this predicted phenomenon illuminates a region with a size notably larger than the TGF source and has detectable levels of brightness. Since the spectroscopic, morphological, and temporal features of this luminous event are closely related with TGFs, corresponding measurements would provide a novel perspective for investigation of TGFs, as well as lightning discharges that produce them.

Luminance- and Texture-Defined Information Processing in School-Aged Children with Autism

PubMed Central

Rivest, Jessica B.; Jemel, Boutheina; Bertone, Armando; McKerral, Michelle; Mottron, Laurent

2013-01-01

According to the complexity-specific hypothesis, the efficacy with which individuals with autism spectrum disorder (ASD) process visual information varies according to the extensiveness of the neural network required to process stimuli. Specifically, adults with ASD are less sensitive to texture-defined (or second-order) information, which necessitates the implication of several cortical visual areas. Conversely, the sensitivity to simple, luminance-defined (or first-order) information, which mainly relies on primary visual cortex (V1) activity, has been found to be either superior (static material) or intact (dynamic material) in ASD. It is currently unknown if these autistic perceptual alterations are present in childhood. In the present study, behavioural (threshold) and electrophysiological measures were obtained for static luminance- and texture-defined gratings presented to school-aged children with ASD and compared to those of typically developing children. Our behavioural and electrophysiological (P140) results indicate that luminance processing is likely unremarkable in autistic children. With respect to texture processing, there was no significant threshold difference between groups. However, unlike typical children, autistic children did not show reliable enhancements of brain activity (N230 and P340) in response to texture-defined gratings relative to luminance-defined gratings. This suggests reduced efficiency of neuro-integrative mechanisms operating at a perceptual level in autism. These results are in line with the idea that visual atypicalities mediated by intermediate-scale neural networks emerge before or during the school-age period in autism. PMID:24205355

Luminance- and texture-defined information processing in school-aged children with autism.

PubMed

Rivest, Jessica B; Jemel, Boutheina; Bertone, Armando; McKerral, Michelle; Mottron, Laurent

2013-01-01

According to the complexity-specific hypothesis, the efficacy with which individuals with autism spectrum disorder (ASD) process visual information varies according to the extensiveness of the neural network required to process stimuli. Specifically, adults with ASD are less sensitive to texture-defined (or second-order) information, which necessitates the implication of several cortical visual areas. Conversely, the sensitivity to simple, luminance-defined (or first-order) information, which mainly relies on primary visual cortex (V1) activity, has been found to be either superior (static material) or intact (dynamic material) in ASD. It is currently unknown if these autistic perceptual alterations are present in childhood. In the present study, behavioural (threshold) and electrophysiological measures were obtained for static luminance- and texture-defined gratings presented to school-aged children with ASD and compared to those of typically developing children. Our behavioural and electrophysiological (P140) results indicate that luminance processing is likely unremarkable in autistic children. With respect to texture processing, there was no significant threshold difference between groups. However, unlike typical children, autistic children did not show reliable enhancements of brain activity (N230 and P340) in response to texture-defined gratings relative to luminance-defined gratings. This suggests reduced efficiency of neuro-integrative mechanisms operating at a perceptual level in autism. These results are in line with the idea that visual atypicalities mediated by intermediate-scale neural networks emerge before or during the school-age period in autism.

The transport and metabolism of the uridine mononucleotides by rat jejunum in vitro.

PubMed Central

Bronk, J R; Hastewell, J G

1989-01-01

1. Both uridine 3'-monophosphate (3'-UMP) and uridine 5'-monophosphate (5'-UMP) when perfused through the lumen of isolated rat jejunum gave rise to uracil as the only transported pyrimidine appearing in the serosal medium; neither the nucleotide nor the nucleoside could be detected in the serosal fluid. 2. There was a low level of the nucleoside, uridine, in the luminal fluid after the nucleotide had passed through the jejunal segment. Luminal nucleoside appearance was more marked from the 3' form of the nucleotide. 3. The hydrolysis of the nucleotides to the nucleoside form occurred via a brush-border membrane enzyme, which had the same maximal velocity (Vmax) for the two nucleotides (699 +/- 35 and 747 +/- 10 nmol min-1 (mg protein)-1 for 3'-UMP and 5'-UMP, respectively) but a different Michaelis constant (Km) so that 3'-UMP (Km = 58 +/- 3 microM) hydrolysis is favoured over 5'-UMP hydrolysis (Km = 108 +/- microM) at lower concentrations. 4. At 0.05 mM, luminal 3'-UMP gave rise to a higher rate of serosal uracil appearance than luminal 5'-UMP, but at higher luminal concentrations (0.1-0.2 mM) the rate of serosal uracil appearance was the same from both nucleotides. 5. The transmural transport of uracil from the uridine mononucleotides is discussed with reference to the metabolism and compartmentalization of the small intestine responsible for the appearance of the free pyrimidine in the serosal fluid. PMID:2778724

Boosting jet power in black hole spacetimes

PubMed Central

Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W.; Liebling, Steven L.; Motl, Patrick M.; Garrett, Travis

2011-01-01

The extraction of rotational energy from a spinning black hole via the Blandford–Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux. PMID:21768341

Scintillating C Ring

NASA Image and Video Library

2007-01-16

Both luminous and translucent, the C ring sweeps out of the darkness of Saturn's shadow and obscures the planet at lower left. The ring is characterized by broad, isolated bright areas, or "plateaus," surrounded by fainter material. This view looks toward the unlit side of the rings from about 19 degrees above the ringplane. North on Saturn is up. The dark, inner B ring is seen at lower right. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 15, 2006 at a distance of approximately 632,000 kilometers (393,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 56 degrees. Image scale is 34 kilometers (21 miles) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA08855

Fine-structural changes in the midgut of old Drosophila melanogaster

NASA Technical Reports Server (NTRS)

Anton-Erxleben, F.; Miquel, J.; Philpott, D. E.

1983-01-01

Senescent fine-structural changes in the midgut of Drosophila melanogaster are investigated. A large number of midgut mitochondria in old flies exhibit nodular cristae and a tubular system located perpendicular to the normal cristae orientation. Anterior intestinal cells show a senescent accumulation of age pigment, either with a surrounding two-unit membrane or without any membrane. The predominant localization of enlarged mitochondria and pigment in the luminal gut region may be related to the polarized metabolism of the intestinal cells. Findings concur with previous observations of dense-body accumulations and support the theory that mitochondria are involved in the aging of fixed post-mitotic cells. Demonstrated by statistical analyses is that mitochondrial size increase is related to mitochondrial variation increase.

Gestalt grouping and common onset masking.

PubMed

Kahan, Todd A; Mathis, Katherine M

2002-11-01

A four-dot mask that surrounds and is presented simultaneously with a briefly presented target will reduce a person's ability to identity that target if the mask persists beyond target offset and attention is divided (Enns & Di Lollo, 1997, 2000). This masking effect, referred to as common onset masking, reflects reentrant processing in the visual system and can best be explained with a theory of object substitution (Di Lollo, Enns, & Rensink, 2000). In the present experiments, we investigated whether Gestalt grouping variables would influence the strength of common onset masking. The results indicated that (1) masking was impervious to grouping by form, similarity of color, position, luminance polarity, and common region and (2) masking increased with the number of elements in the masking display.

Spitzer Observations of the X-ray Sources of NGC 4485/90

NASA Astrophysics Data System (ADS)

Vazquez, Gerardo A.; Colbert, E.; Hornschemeier, A.; Malhotra, S.; Roberts, T.; Ward, M.

2006-06-01

The mechanism for forming (or igniting) so-called Ultra-Luminous X- ray sources (ULXs) is very poorly understood. In order to investigate the stellar and gaseous environment of ULXs, we have observed the nearby starburst galaxy system NGC 4485/90 with Spitzer's IRAC and IRS instruments. High-quality mid-infrared images and spectra are used to characterize the stellar history of stars near the ULXs, and the ionization state of the surrounding gas. NGC 4485/90 fortuitively hosts six ULXs, and we have analyzed IRAC images and IRS spectra of all six regions. We also observed two "comparison" regions with no X-ray sources. Here we present our preliminary findings on the similarities and differences between the stellar and gaseous components near the ULXs.

Genome-wide Search of Oncogenic Pathways Cooperating with ETS Fusions in Prostate Cancer

DTIC Science & Technology

2013-07-01

luminal cells cannot engraft well in this assay), and although both luminal and basal cells could serve as cells of origin of prostate cancer, luminal ...was the need for them to differentiate into luminal cells first [27]. Thus, it appears that prostate luminal cells may serve as the major cellular...origin for prostate cancer. We therefore more favor a strategy to search for ETS-cooperating mutations in prostate luminal cells. Furthermore

Early suppression effect in human primary visual cortex during Kanizsa illusion processing: A magnetoencephalographic evidence.

PubMed

Chernyshev, Boris V; Pronko, Platon K; Stroganova, Tatiana A

2016-01-01

Detection of illusory contours (ICs) such as Kanizsa figures is known to depend primarily upon the lateral occipital complex. Yet there is no universal agreement on the role of the primary visual cortex in this process; some existing evidence hints that an early stage of the visual response in V1 may involve relative suppression to Kanizsa figures compared with controls. Iso-oriented luminance borders, which are responsible for Kanizsa illusion, may evoke surround suppression in V1 and adjacent areas leading to the reduction in the initial response to Kanizsa figures. We attempted to test the existence, as well as to find localization and timing of the early suppression effect produced by Kanizsa figures in adult nonclinical human participants. We used two sizes of visual stimuli (4.5 and 9.0°) in order to probe the effect at two different levels of eccentricity; the stimuli were presented centrally in passive viewing conditions. We recorded magnetoencephalogram, which is more sensitive than electroencephalogram to activity originating from V1 and V2 areas. We restricted our analysis to the medial occipital area and the occipital pole, and to a 40-120 ms time window after the stimulus onset. By applying threshold-free cluster enhancement technique in combination with permutation statistics, we were able to detect the inverted IC effect-a relative suppression of the response to the Kanizsa figures compared with the control stimuli. The current finding is highly compatible with the explanation involving surround suppression evoked by iso-oriented collinear borders. The effect may be related to the principle of sparse coding, according to which V1 suppresses representations of inner parts of collinear assemblies as being informationally redundant. Such a mechanism is likely to be an important preliminary step preceding object contour detection.

Influence of Spatial and Chromatic Noise on Luminance Discrimination.

PubMed

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

2017-12-05

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

Luminous bacteria cultured from fish guts in the Gulf of Oman.

PubMed

Makemson, J C; Hermosa, G V

1999-01-01

The incidence of culturable luminous bacteria in Omani market fish guts was correlated to habitat type amongst 109 species of fish. Isolated representative luminous bacteria were compared to known species using the Biolog system (95 traits/isolate) and cluster analysis, which showed that the main taxa present in fish guts were clades related to Vibrio harveyi and Photobacterium species with sporadic incidence of P. phosphoreum. The luminous isolates from gut of the slip-mouth (barred pony fish), Leiognathus fasciatus, were mainly a type related to Photobacterium but phenotypically different from known species. These luminous gut bacteria were identical with the bacteria in the light organ, indicating that the light organ supplies a significant quantity of luminous bacteria to the gut. In many of the fish that lack light organs, luminous bacteria were also the dominant bacterial type in the gut, while in some others luminous bacteria were encountered sporadically and at low densities, reflecting the incidence of culturable luminous bacteria in seawater. Pelagic fish contained the highest incidence of culturable luminous bacteria and reef-associated fish the lowest. No correlation was found between the incidence of culturable luminous bacteria and the degree to which fish produce a melanin-covered gut. Copyright 1999 John Wiley & Sons, Ltd.

Half of the Most Luminous Quasars May Be Obscured: Investigating the Nature of WISE-Selected Hot Dust-Obscured Galaxies

NASA Astrophysics Data System (ADS)

Assef, R. J.; Eisenhardt, P. R. M.; Stern, D.; Tsai, C.-W.; Wu, J.; Wylezalek, D.; Blain, A. W.; Bridge, C. R.; Donoso, E.; Gonzales, A.; Griffith, R. L.; Jarrett, T. H.

2015-05-01

The Wide-field Infrared Survey Explorer mission has unveiled a rare population of high-redshift (z = 1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities {{L}IR}\\gt {{10}13} {{L}⊙ }, and sometimes exceeding {{10}14} {{L}⊙ }. Previous work has shown that their dust temperatures and overall far-infrared spectral energy distributions (SEDs) are significantly hotter than expected to be powered by star formation. We present here an analysis of the rest-frame optical through mid-infrared SEDs for a large sample of these so-called “hot, dust-obscured galaxies” (Hot DOGs). We find that the SEDs of Hot DOGs are generally well modeled by the combination of a luminous, yet obscured active galactic nuclei (AGNs) that dominates the rest-frame emission at λ \\gt 1 μ m and the bolometric luminosity output, and a less luminous host galaxy that is responsible for the bulk of the rest optical/UV emission. Even though the stellar mass of the host galaxies may be as large as 1011-1012 M⊙, the AGN emission, with a range of luminosities comparable to those of the most luminous QSOs known, require that either Hot DOGs have black hole masses significantly in excess of the local relations, or that they radiate significantly above the Eddington limit, at a level at least 10 times more efficiently than z ˜ 2 QSOs. We show that, while rare, the number density of Hot DOGs is comparable to that of equally luminous but unobscured (i.e., Type 1) QSOs. This may be at odds with the trend suggested at lower luminosities for the fraction of obscured AGNs to decrease with increasing luminosity. That trend may, instead, reverse at higher luminosities. Alternatively, Hot DOGs may not be the torus-obscured counterparts of the known optically selected, largely unobscured, hyper-luminous QSOs, and may represent a new component of the galaxy evolution paradigm. Finally, we discuss the environments of Hot DOGs and statistically show that these objects are in regions as dense as those of known high-redshift proto-clusters.

Candidate Luminal B Breast Cancer Genes Identified by Genome, Gene Expression and DNA Methylation Profiling

PubMed Central

Addou-Klouche, Lynda; Finetti, Pascal; Saade, Marie-Rose; Manai, Marwa; Carbuccia, Nadine; Bekhouche, Ismahane; Letessier, Anne; Charafe-Jauffret, Emmanuelle; Jacquemier, Jocelyne; Spicuglia, Salvatore; de The, Hugues; Viens, Patrice; Bertucci, François; Birnbaum, Daniel; Chaffanet, Max

2014-01-01

Breast cancers (BCs) of the luminal B subtype are estrogen receptor-positive (ER+), highly proliferative, resistant to standard therapies and have a poor prognosis. To better understand this subtype we compared DNA copy number aberrations (CNAs), DNA promoter methylation, gene expression profiles, and somatic mutations in nine selected genes, in 32 luminal B tumors with those observed in 156 BCs of the other molecular subtypes. Frequent CNAs included 8p11-p12 and 11q13.1-q13.2 amplifications, 7q11.22-q34, 8q21.12-q24.23, 12p12.3-p13.1, 12q13.11-q24.11, 14q21.1-q23.1, 17q11.1-q25.1, 20q11.23-q13.33 gains and 6q14.1-q24.2, 9p21.3-p24,3, 9q21.2, 18p11.31-p11.32 losses. A total of 237 and 101 luminal B-specific candidate oncogenes and tumor suppressor genes (TSGs) presented a deregulated expression in relation with their CNAs, including 11 genes previously reported associated with endocrine resistance. Interestingly, 88% of the potential TSGs are located within chromosome arm 6q, and seven candidate oncogenes are potential therapeutic targets. A total of 100 candidate oncogenes were validated in a public series of 5,765 BCs and the overexpression of 67 of these was associated with poor survival in luminal tumors. Twenty-four genes presented a deregulated expression in relation with a high DNA methylation level. FOXO3, PIK3CA and TP53 were the most frequent mutated genes among the nine tested. In a meta-analysis of next-generation sequencing data in 875 BCs, KCNB2 mutations were associated with luminal B cases while candidate TSGs MDN1 (6q15) and UTRN (6q24), were mutated in this subtype. In conclusion, we have reported luminal B candidate genes that may play a role in the development and/or hormone resistance of this aggressive subtype. PMID:24416132

ß-Adrenergic Stimulation Increases RyR2 Activity via Intracellular Ca2+ and Mg2+ Regulation

PubMed Central

Li, Jiao; Imtiaz, Mohammad S.; Beard, Nicole A.; Dulhunty, Angela F.; Thorne, Rick; vanHelden, Dirk F.; Laver, Derek R.

2013-01-01

Here we investigate how ß-adrenergic stimulation of the heart alters regulation of ryanodine receptors (RyRs) by intracellular Ca2+ and Mg2+ and the role of these changes in SR Ca2+ release. RyRs were isolated from rat hearts, perfused in a Langendorff apparatus for 5 min and subject to 1 min perfusion with 1 µM isoproterenol or without (control) and snap frozen in liquid N2 to capture their phosphorylation state. Western Blots show that RyR2 phosphorylation was increased by isoproterenol, confirming that RyR2 were subject to normal ß-adrenergic signaling. Under basal conditions, S2808 and S2814 had phosphorylation levels of 69% and 15%, respectively. These levels were increased to 83% and 60%, respectively, after 60 s of ß-adrenergic stimulation consistent with other reports that ß-adrenergic stimulation of the heart can phosphorylate RyRs at specific residues including S2808 and S2814 causing an increase in RyR activity. At cytoplasmic [Ca2+] <1 µM, ß-adrenergic stimulation increased luminal Ca2+ activation of single RyR channels, decreased luminal Mg2+ inhibition and decreased inhibition of RyRs by mM cytoplasmic Mg2+. At cytoplasmic [Ca2+] >1 µM, ß-adrenergic stimulation only decreased cytoplasmic Mg2+ and Ca2+ inhibition of RyRs. The Ka and maximum levels of cytoplasmic Ca2+ activation site were not affected by ß-adrenergic stimulation. Our RyR2 gating model was fitted to the single channel data. It predicted that in diastole, ß-adrenergic stimulation is mediated by 1) increasing the activating potency of Ca2+ binding to the luminal Ca2+ site and decreasing its affinity for luminal Mg2+ and 2) decreasing affinity of the low-affinity Ca2+/Mg2+ cytoplasmic inhibition site. However in systole, ß-adrenergic stimulation is mediated mainly by the latter. PMID:23533585

Pattern of recurrence of early breast cancer is different according to intrinsic subtype and proliferation index

PubMed Central

2013-01-01

Introduction Recurrence risk in breast cancer varies throughout the follow-up time. We examined if these changes are related to the level of expression of the proliferation pathway and intrinsic subtypes. Methods Expression of estrogen and progesterone receptor, Ki-67, human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR) and cytokeratin 5/6 (CK 5/6) was performed on tissue-microarrays constructed from a large and uniformly managed series of early breast cancer patients (N = 1,249). Subtype definitions by four biomarkers were as follows: luminal A (ER + and/or PR+, HER2-, Ki-67 <14), luminal B (ER + and/or PR+, HER2-, Ki-67 ≥14), HER2-enriched (any ER, any PR, HER2+, any Ki-67), triple-negative (ER-, PR-, HER2-, any Ki-67). Subtype definitions by six biomarkers were as follows: luminal A (ER + and/or PR+, HER2-, Ki-67 <14, any CK 5/6, any EGFR), luminal B (ER + and/or PR+, HER2-, Ki-67 ≥14, any CK 5/6, any EGFR), HER2-enriched (ER-, PR-, HER2+, any Ki-67, any CK 5/6, any EGFR), Luminal-HER2 (ER + and/or PR+, HER2+, any Ki-67, any CK 5/6, any EGFR), Basal-like (ER-, PR-, HER2-, any Ki-67, CK5/6+ and/or EGFR+), triple-negative nonbasal (ER-, PR-, HER2-, any Ki-67, CK 5/6-, EGFR-). Each four- or six-marker defined intrinsic subtype was divided in two groups, with Ki-67 <14% or with Ki-67 ≥14%. Recurrence hazard rate function was determined for each intrinsic subtype as a whole and according to Ki-67 value. Results Luminal A displayed a slow risk increase, reaching its maximum after three years and then remained steady. Luminal B presented most of its relapses during the first five years. HER2-enriched tumors show a peak of recurrence nearly twenty months post-surgery, with a greater risk in Ki-67 ≥14%. However a second peak occurred at 72 months but the risk magnitude was greater in Ki-67 <14%. Triple negative tumors with low proliferation rate display a smooth risk curve, but with Ki-67 ≥14% show sharp peak at nearly 18 months. Conclusions Each intrinsic subtype has a particular pattern of relapses over time which change depending on the level of activation of the proliferation pathway assessed by Ki-67. These findings could have clinical implications both on adjuvant treatment trial design and on the recommendations concerning the surveillance of patients. PMID:24148581

Investigation of Dual Active Nuclei, Outflows, Shock-heated Gas, and Young Star Clusters in Markarian 266

NASA Astrophysics Data System (ADS)

Mazzarella, J. M.; Iwasawa, K.; Vavilkin, T.; Armus, L.; Kim, D.-C.; Bothun, G.; Evans, A. S.; Spoon, H. W. W.; Haan, S.; Howell, J. H.; Lord, S.; Marshall, J. A.; Ishida, C. M.; Xu, C. K.; Petric, A.; Sanders, D. B.; Surace, J. A.; Appleton, P.; Chan, B. H. P.; Frayer, D. T.; Inami, H.; Khachikian, E. Ye.; Madore, B. F.; Privon, G. C.; Sturm, E.; U, Vivian; Veilleux, S.

2012-11-01

Results of observations with the Spitzer, Hubble, GALEX, Chandra, and XMM-Newton space telescopes are presented for the luminous infrared galaxy (LIRG) merger Markarian 266. The SW (Seyfert 2) and NE (LINER) nuclei reside in galaxies with Hubble types SBb (pec) and S0/a (pec), respectively. Both companions are more luminous than L* galaxies and they are inferred to each contain a ≈2.5 × 108 M ⊙ black hole. Although the nuclei have an observed hard X-ray flux ratio of fX (NE)/fX (SW) = 6.4, Mrk 266 SW is likely the primary source of a bright Fe Kα line detected from the system, consistent with the reflection-dominated X-ray spectrum of a heavily obscured active galactic nucleus (AGN). Optical knots embedded in an arc with aligned radio continuum radiation, combined with luminous H2 line emission, provide evidence for a radiative bow shock in an AGN-driven outflow surrounding the NE nucleus. A soft X-ray emission feature modeled as shock-heated plasma with T ~ 107 K is cospatial with radio continuum emission between the galaxies. Mid-infrared diagnostics provide mixed results, but overall suggest a composite system with roughly equal contributions of AGN and starburst radiation powering the bolometric luminosity. Approximately 120 star clusters have been detected, with most having estimated ages less than 50 Myr. Detection of 24 μm emission aligned with soft X-rays, radio continuum, and ionized gas emission extending ~34'' (20 kpc) north of the galaxies is interpreted as ~2 × 107 M ⊙ of dust entrained in an outflowing superwind. At optical wavelengths this Northern Loop region is resolved into a fragmented morphology indicative of Rayleigh-Taylor instabilities in an expanding shell of ionized gas. Mrk 266 demonstrates that the dust "blow-out" phase can begin in a LIRG well before the galaxies fully coalesce during a subsequent ultraluminous infrared galaxy (ULIRG) phase, and rapid gas consumption in luminous dual AGNs with kiloparsec-scale separations early in the merger process may explain the paucity of detected binary QSOs (with parsec-scale orbital separations) in spectroscopic surveys. An evolutionary sequence is proposed representing a progression from dual to binary AGNs, accompanied by an increase in observed Lx /L ir ratios by over two orders of magnitude.

Research on the calibration methods of the luminance parameter of radiation luminance meters

NASA Astrophysics Data System (ADS)

Cheng, Weihai; Huang, Biyong; Lin, Fangsheng; Li, Tiecheng; Yin, Dejin; Lai, Lei

2017-10-01

This paper introduces standard diffusion reflection white plate method and integrating sphere standard luminance source method to calibrate the luminance parameter. The paper compares the effects of calibration results by using these two methods through principle analysis and experimental verification. After using two methods to calibrate the same radiation luminance meter, the data obtained verifies the testing results of the two methods are both reliable. The results show that the display value using standard white plate method has fewer errors and better reproducibility. However, standard luminance source method is more convenient and suitable for on-site calibration. Moreover, standard luminance source method has wider range and can test the linear performance of the instruments.

Sign luminance requirements for various background complexities

DOT National Transportation Integrated Search

1985-09-01

The Federal standards (FP-79) for luminance of retroreflective materials for traffic signs are acceptance standards; they provide no differentiation based on driver need. Driver needs for sign luminance are of 3 types -- luminance for sign comprehens...

Human prostate luminal cell differentiation requires NOTCH3 induction by p38-MAPK and MYC.

PubMed

Frank, Sander B; Berger, Penny L; Ljungman, Mats; Miranti, Cindy K

2017-06-01

Many pathways dysregulated in prostate cancer are also involved in epithelial differentiation. To better understand prostate tumor initiation, we sought to investigate specific genes and mechanisms required for normal basal to luminal cell differentiation. Utilizing human prostate basal epithelial cells and an in vitro differentiation model, we tested the hypothesis that regulation of NOTCH3 by the p38 MAPK family (hereafter p38-MAPK), via MYC, is required for luminal differentiation. Inhibition (SB202190 and BIRB796) or knockdown of p38α (also known as MAPK14) and/or p38δ (also known as MAPK13) prevented proper differentiation. Additionally, treatment with a γ-secretase inhibitor (RO4929097) or knockdown of NOTCH1 and/or NOTCH3 greatly impaired differentiation and caused luminal cell death. Constitutive p38-MAPK activation through MKK6(CA) increased NOTCH3 (but not NOTCH1) mRNA and protein levels, which was diminished upon MYC inhibition (10058-F4 and JQ1) or knockdown. Furthermore, we validated two NOTCH3 enhancer elements through a combination of enhancer (e)RNA detection (BruUV-seq) and luciferase reporter assays. Finally, we found that the NOTCH3 mRNA half-life increased during differentiation or upon acute p38-MAPK activation. These results reveal a new connection between p38-MAPK, MYC and NOTCH signaling, demonstrate two mechanisms of NOTCH3 regulation and provide evidence for NOTCH3 involvement in prostate luminal cell differentiation. © 2017. Published by The Company of Biologists Ltd.

[Experimental study on a novel esophageal prosthesis made of composite biomaterials].

PubMed

Qin, Xiong; Xu, Zhi-fei; Shi, Hong-can; Zhao, Xue-wei; Sun, Kang; Gao, Xiang-yang

2003-07-01

To design and develop a novel esophageal prosthesis by selecting appropriate biomaterials, developing special manufacturing techniques, and investigating the feasibility of replacement of cervical esophagus in mongrel dogs. In accordance with the requirements of ideal esophageal substitutes, we designed a new type of esophageal prostheses. The inner stent were made with polyurethane of medical grade, and the outer surface of the prosthesis was coated with collagen-chitosan sponge. The silicone tube was used as a control. Thirteen adult mongrel dogs that were divided into two groups were used to establish the experimental models. In the experimental group (n = 8), the esophageal prostheses were completely incorporated with the native esophagus and adherent to the surrounding host connective tissues. Epithelial linings of varying degrees were formed on the luminal surface, and complete epithelization was seen in 1 month postoperatively. The granulation at the sites of the anastomosis in this group was less significant than that of the control group. One dog has been surviving for 12 months up to now without any complications. In the control group (n = 5), esophageal epithelial was not observed on the luminal surface, constriction of the regenerated esophagus progressed and all the dogs died within 2 months after operation. These observations suggest that this esophageal prosthesis made of composite biomaterials has high biocompatibility and potential for long-segment esophageal reconstruction, which is promising for the clinical repair of esophageal defects.

p-STAT3 in luminal breast cancer: Integrated RNA-protein pooled analysis and results from the BIG 2-98 phase III trial.

PubMed

Sonnenblick, Amir; Salgado, Roberto; Brohée, Sylvain; Zahavi, Tamar; Peretz, Tamar; Van den Eynden, Gert; Rouas, Ghizlane; Salmon, Asher; Francis, Prudence A; Di Leo, Angelo; Crown, John P A; Viale, Giuseppe; Daly, Laura; Javdan, Bahar; Fujisawa, Sho; De Azambuja, Evandro; Lieveke, Ameye; Piccart, Martine J; Bromberg, Jacqueline F; Sotiriou, Christos

2018-02-01

In the present study, in order to investigate the role of signal transducer and activator of transcription 3 (STAT3) in estrogen receptor (ER)-positive breast cancer prognosis, we evaluated the phosphorylated STAT3 (p-STAT3) status and investigated its effect on the outcome in a pooled analysis and in a large prospective adjuvant trial. By using the TCGA repository, we developed gene signatures that reflected the level of p-STAT3. Using pooled analysis of the expression data from luminal breast cancer patients, we assessed the effects of the p-STAT3 expression signature on prognosis. We further validated the p-STAT3 prognostic effect using immunohistochemistry (IHC) and immunofluorescence staining of p-STAT3 tissue microarrays from a large randomised prospective trial. Our analysis demonstrated that p-STAT3 expression was elevated in luminal A-type breast cancer (Kruskal-Wallis test, P<10e-10) and was significantly associated with a good prognosis (log-rank, P<10e-10). Notably, the p-STAT3 expression signature identified patients with a good prognosis irrespective of the luminal subtype (log-rank: luminal A, P=0.026; luminal B, P=0.006). p-STAT3 staining by IHC in the stroma or tumour was detected in 174 out of 610 ER-positive samples (28.5%) from the BIG 2-98 randomised trial. With a median follow-up of 10.1 years, p-STAT3 was associated with a reduced risk of recurrence in ER-positive/HER2-negative breast cancer (Cox univariate HR, 0.66; 95% CI, 0.44-0.98; P=0.04). On the whole, our data indicate that p-STAT3 is associated with an improved outcome in ER-positive breast cancer.

Collagen Matrix Remodeling in Stented Pulmonary Arteries after Transapical Heart Valve Replacement.

PubMed

Ghazanfari, Samaneh; Driessen-Mol, Anita; Hoerstrup, Simon P; Baaijens, Frank P T; Bouten, Carlijn V C

2016-01-01

The use of valved stents for minimally invasive replacement of semilunar heart valves is expected to change the extracellular matrix and mechanical function of the native artery and may thus impair long-term functionality of the implant. Here we investigate the impact of the stent on matrix remodeling of the pulmonary artery in a sheep model, focusing on matrix composition and collagen (re)orientation of the host tissue. Ovine native pulmonary arteries were harvested 8 (n = 2), 16 (n = 4) and 24 (n = 2) weeks after transapical implantation of self-expandable stented heart valves. Second harmonic generation (SHG) microscopy was used to assess the collagen (re)orientation of fresh tissue samples. The collagen and elastin content was quantified using biochemical assays. SHG microscopy revealed regional differences in collagen organization in all explants. In the adventitial layer of the arterial wall far distal to the stent (considered as the control tissue), we observed wavy collagen fibers oriented in the circumferential direction. These circumferential fibers were more straightened in the adventitial layer located behind the stent. On the luminal side of the wall behind the stent, collagen fibers were aligned along the stent struts and randomly oriented between the struts. Immediately distal to the stent, however, fibers on both the luminal and the adventitial side of the wall were oriented in the axial direction, demonstrating the stent impact on the collagen structure of surrounding arterial tissues. Collagen orientation patterns did not change with implantation time, and biochemical analyses showed no changes in the trend of collagen and elastin content with implantation time or location of the vascular wall. We hypothesize that the collagen fibers on the adventitial side of the arterial wall and behind the stent straighten in response to the arterial stretch caused by oversizing of the stent. However, the collagen organization on the luminal side suggests that stent-induced remodeling is dominated by contact guidance. © 2016 S. Karger AG, Basel.

Morphology of brood pouch formation in the pot-bellied seahorse Hippocampus abdominalis.

PubMed

Kawaguchi, Mari; Okubo, Ryohei; Harada, Akari; Miyasaka, Kazuki; Takada, Kensuke; Hiroi, Junya; Yasumasu, Shigeki

2017-01-01

The reproductive strategies of vertebrates are diverse. Seahorses (Pisces: Syngnathidae) possess the unique characteristic of male pregnancy; i.e., males, not females, incubate embryos in a specialized structure called a 'brood pouch'. The brood pouch is formed along the ventral midline of the tail. The lumen of the brood pouch is surrounded by loose connective tissue, called pseudoplacenta, and dermis. We visualized and evaluated the morphology of brood pouch formation in Hippocampus abdominalis to gain generalizable insights into this process in seahorses. First, we employed several staining methods to characterize the pseudoplacenta and dermis of the brood pouch of mature male seahorses. The pseudoplacenta is composed mainly of reticular fibers, while the dermis is composed mainly of collagenous fibers. Further observations showed that pouch formation is initiated by linear projections of epithelia on both ventrolateral sides of the body. These projections elongated toward the ventral midline, eventually fused together, and then formed a baggy structure composed of a single dermis layer with neither smooth muscle nor pseudoplacenta. Finally, the pseudoplacenta was formed, together with two layers of dermis and smooth muscle. Thus, a fully developed brood pouch was established. The morphology of the luminal epithelium also changed during pouch formation. We analyzed the localization of C-type lectins as markers; haCTL II was localized in both the outer and luminal epithelia of the brood pouch throughout development in the male seahorse, whereas haCTL IV, which was not detected in the early stage of seahorse development, became localized only in the luminal epithelium as development proceeded. We categorized the processes of brood pouch formation during male seahorse development into three stages: (1) the early stage, characterized by formation of a baggy structure from the primordium; (2) the middle stage, characterized by the differentiation and establishment of brood pouch-specific tissues; and (3) the late stage, characterized by a fully formed pouch with developing blood vessels and a pouch fold ultimately capable of carrying and incubating embryos.

Strong Clustering of Lyman Break Galaxies around Luminous Quasars at Z ˜ 4

NASA Astrophysics Data System (ADS)

García-Vergara, Cristina; Hennawi, Joseph F.; Barrientos, L. Felipe; Rix, Hans-Walter

2017-10-01

In the standard picture of structure formation, the first massive galaxies are expected to form at the highest peaks of the density field, which constitute the cores of massive proto-clusters. Luminous quasars (QSOs) at z ˜ 4 are the most strongly clustered population known, and should thus reside in massive dark matter halos surrounded by large overdensities of galaxies, implying a strong QSO-galaxy cross-correlation function. We observed six z ˜ 4 QSO fields with VLT/FORS, exploiting a novel set of narrow-band filters custom designed to select Lyman Break Galaxies (LBGs) in a thin redshift slice of {{Δ }}z˜ 0.3, mitigating the projection effects that have limited the sensitivity of previous searches for galaxies around z≳ 4 QSOs. We find that LBGs are strongly clustered around QSOs, and present the first measurement of the QSO-LBG cross-correlation function at z ˜ 4, on scales of 0.1≲ R≲ 9 {h}-1 {Mpc} (comoving). Assuming a power-law form for the cross-correlation function ξ ={(r/{r}0{QG})}γ , we measure {r}0{QG}={8.83}-1.51+1.39 {h}-1 {Mpc} for a fixed slope of γ =2.0. This result is in agreement with the expected cross-correlation length deduced from measurements of the QSO and LBG auto-correlation function, and assuming a deterministic bias model. We also measure a strong auto-correlation of LBGs in our QSO fields, finding {r}0{GG}={21.59}-1.69+1.72 {h}-1 {Mpc} for a fixed slope of γ =1.5, which is ˜4 times larger than the LBG auto-correlation length in blank fields, providing further evidence that QSOs reside in overdensities of LBGs. Our results qualitatively support a picture where luminous QSOs inhabit exceptionally massive ({M}{halo}> {10}12 {M}⊙ ) dark matter halos at z ˜ 4.

METALLICITY EVOLUTION OF THE SIX MOST LUMINOUS M31 DWARF SATELLITES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Nhung; Geha, Marla; Tollerud, Erik J.

We present global metallicity properties, metallicity distribution functions (MDFs), and radial metallicity profiles for the six most luminous M31 dwarf galaxy satellites: M32, NGC 205, NGC 185, NGC 147, Andromeda VII, and Andromeda II. The results presented are the first spectroscopic MDFs for dwarf systems surrounding a host galaxy other than the Milky Way (MW). Our sample consists of individual metallicity measurements for 1243 red giant branch member stars spread across these six systems. We determine metallicities based on the strength of the Ca II triplet lines using the empirical calibration of Carrera et al., which is calibrated over the metallicity range –4 < [Fe/H] <+0.5. We findmore » that these M31 satellites lie on the same luminosity-metallicity relationship as the MW dwarf satellites. We do not find a trend between the internal metallicity spread and galaxy luminosity, contrary to previous studies. The MDF widths of And II and And VII are similar to the MW dwarf spheroidal (dSph) satellites of comparable luminosity; however, our four brightest M31 dwarf satellites are more luminous than any of the MW dSphs and have broader MDFs. The MDFs of our six M31 dwarf satellites are consistent with the leaky box model of chemical evolution, although our metallicity errors allow a wide range of evolution models. We find a significant radial gradient in metallicity in only two of our six systems, NGC 185 and Andromeda II, and flat radial metallicity gradients in the rest of our sample with no observed correlation between rotational support and radial metallicity gradients. Although the average properties and radial trends of the M31 dwarf galaxies agree with their MW counterparts at similar luminosity, the detailed MDFs are different, particularly at the metal-rich end.« less

Non-identical distribution pattern of epidermal growth factor and platelet-derived growth factor in the mouse uterus during the oestrous cycle and early pregnancy.

PubMed

Jaber, L; Kan, F W

1998-10-01

In the present study, we examined by immunohistochemistry the cell-specific distribution of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) in the mouse uterus during the oestrous cycle and throughout the first 7 days of pregnancy. Paraffin-embedded tissue samples were immunostained using the avidin-biotin peroxidase technique and then examined by light microscopy. Our results showed that immunostaining for EGF was detected in the stroma but not in the luminal or glandular epithelium. A high concentration of EGF was detected in the stroma around the time of embryo implantation at days 3, 4 and 5 of pregnancy. The implanted embryo at day 7 of gestation showed immunostaining for EGF between the ectoderm and endoderm layers. The cell distribution pattern for PDGF was found to be different from that observed with EGF. Luminal and glandular epithelia displayed PDGF immunostaining throughout the first 7 days of pregnancy, with the highest intensity at days 4 and 5 of gestation. In contrast, no immunostaining was observed in the luminal and glandular epithelia at post-oestrus, dioestrus and pro-oestrus stages. However, a weak reaction started to appear at oestrus. The embryo at the blastocyst stage displayed a strong immunoreaction for antibody against PDGF. In addition, the decidual boundary zone surrounding the implanted embryo at days 5, 6 and 7 of gestation also showed an immunostaining for PDGF. The present observations demonstrate clearly the presence of EGF and PDGF in the mouse uterus in high concentrations at the peri-implantation period. Thus, our results, together with what is known about the effect of EGF and PDGF in controlling the growth, differentiation and activation of a variety of cell types, suggest a possible role for these growth factors during the preparation of the endometrium for implantation in controlling the proliferation activity of stromal and/or epithelial cells.

BCL-2 and BCL-XL expression are down-regulated in benign prostate hyperplasia nodules and not affected by finasteride and/or celecoxib

PubMed Central

Li, Feng; Pascal, Laura E; Zhou, Jianhua; Zhou, Yibin; Wang, Ke; Parwani, Anil V; Dhir, Rajiv; Guo, Peng; He, Dalin; Nelson, Joel B; Wang, Zhou

2018-01-01

The mechanisms involved in the development of benign prostatic hyperplasia (BPH) are poorly understood. One potential mechanism involved in BPH pathogenesis may involve altered expression of genes related to apoptosis and proliferation because reduced cell death and increased proliferation are thought to contribute to prostatic enlargement. This study examined the expression of B-cell lymphoma 2 (BCL-2) and B-cell lymphoma-extra large (BCL-XL), two important anti-apoptosis factors that are also capable of inhibiting cell proliferation via accelerated G1 arrest or delayed G1/S transition, using immunostaining in simple prostatectomy BPH specimens from patients naïve to androgen manipulation. Since androgens and inflammation are thought to play important roles in BPH pathogenesis, we tested the effect of inhibiting 5a-reductase and/or COX-2 on the expression of BCL-2 and BCL-XL in BPH specimens from prostate cancer patients with BPH. These patients had no prior use of chronic NSAIDs and/or 5a-reductase inhibitors and were treated with celecoxib, finasteride, celecoxib plus finasteride or no treatment for 28 consecutive days prior to surgery. In all specimens, BCL-2 and BCL-XL staining was evident in both luminal and basal epithelial cells, with more intense staining in basal cells. Both luminal and basal cells exhibited decreased BCL-2 and BCL-XL staining in BPH nodules compared to the surrounding normal prostatic tissues. In prostate cancer patients with BPH, celecoxib and/or finasteride did not affect the expression of BCL-2 and BCL-XL in luminal or basal cells in BPH nodules and normal adjacent tissues. These results suggest that BCL-2 and BCL-XL may act as anti-proliferative factors in BPH pathogenesis, and the effect of celecoxib and/or finasteride on BPH is unlikely mediated through modulating BCL-2 and BCL-XL signaling. PMID:29531971

A new role of SNAI2 in postlactational involution of the mammary gland links it to luminal breast cancer development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castillo-Lluva, Sonia; Hontecillas-Prieto, Lourdes; Blanco-Gómez, Adrian

Breast cancer is a major cause of mortality in women. The transcription factor SNAI2 has been implicated in the pathogenesis of several types of cancer, including breast cancer of basal origin. Here we show that SNAI2 is also important in the development of breast cancer of luminal origin in MMTV-ErbB2 mice. SNAI2 deficiency leads to longer latency and fewer luminal tumors, both of these being characteristics of pretumoral origin. These effects were associated with reduced proliferation and a decreased ability to generate mammospheres in normal mammary glands. However, the capacity to metastasize was not modified. Under conditions of increased ERBB2more » oncogenic activity after pregnancy plus SNAI2 deficiency, both pretumoral defects-latency and tumor load-were compensated. However, the incidence of lung metastases was dramatically reduced. Furthermore, SNAI2 was required for proper postlactational involution of the breast. At 3 days post lactational involution, the mammary glands of Snai2-deficient mice exhibited lower levels of pSTAT3 and higher levels of pAKT1, resulting in decreased apoptosis. Abundant noninvoluted ducts were still present at 30 days post lactation, with a greater number of residual ERBB2+ cells. These results suggest that this defect in involution leads to an increase in the number of susceptible target cells for transformation, to the recovery of the capacity to generate mammospheres and to an increase in the number of tumors. In conclusion, our work demonstrates the participation of SNAI2 in the pathogenesis of luminal breast cancer, and reveals an unexpected connection between the processes of postlactational involution and breast tumorigenesis in Snai2-null mutant mice.« less

A new role of SNAI2 in post-lactational involution of the mammary gland links it to luminal breast cancer development

PubMed Central

Castillo-Lluva, Sonia; Hontecillas-Prieto, Lourdes; Blanco-Gómez, Adrián; Sáez-Freire, María del Mar; García-Cenador, Begoña; García-Criado, Javier; Pérez-Andrés, Martín; de Matos, Alberto Orfao; Cañamero, Marta; Mao, Jian-Hua; Gridley, Thomas; Castellanos-Martín, Andrés; Pérez-Losada, Jesús

2015-01-01

Breast cancer is a major cause of mortality in women. The transcription factor SNAI2 has been implicated in the pathogenesis of several types of cancer, including breast cancer of basal origin. Here we show that SNAI2 is also important in the development of breast cancer of luminal origin in MMTV-ErbB2 mice. SNAI2 deficiency leads to longer latency and fewer luminal tumors, both of these being characteristics of pre-tumoral origin. These effects were associated with reduced proliferation and a decreased ability to generate mammospheres in normal mammary glands. However, the capacity to metastasize was not modified. Under conditions of increased ERBB2 oncogenic activity after pregnancy plus SNAI2 deficiency, both pretumoral defects-latency and tumor load- were compensated. However, the incidence of lung metastases was dramatically reduced. Furthermore, SNAI2 was required for proper post-lactational involution of the breast. At three days post-lactational involution, the mammary glands of Snai2-deficient mice exhibited lower levels of pSTAT3 and higher levels pAKT1, resulting in decreased apoptosis. The presence of abundant non-involuted ducts was still present at 30 days post-lactation, with a greater number of residual ERBB2+ cells. These results suggest that this defect in involution leads to an increase in the number of susceptible target cells for transformation, to the recovery of the capacity to generate mammospheres, and to an increase in the number of tumors. Our work demonstrates the participation of SNAI2 in the pathogenesis of luminal breast cancer, and reveals an unexpected connection between the processes of post-lactational involution and breast tumorigenesis in Snai2-null mutant mice. PMID:26096931

A new role of SNAI2 in postlactational involution of the mammary gland links it to luminal breast cancer development

DOE PAGES

Castillo-Lluva, Sonia; Hontecillas-Prieto, Lourdes; Blanco-Gómez, Adrian; ...

2015-06-22

Breast cancer is a major cause of mortality in women. The transcription factor SNAI2 has been implicated in the pathogenesis of several types of cancer, including breast cancer of basal origin. Here we show that SNAI2 is also important in the development of breast cancer of luminal origin in MMTV-ErbB2 mice. SNAI2 deficiency leads to longer latency and fewer luminal tumors, both of these being characteristics of pretumoral origin. These effects were associated with reduced proliferation and a decreased ability to generate mammospheres in normal mammary glands. However, the capacity to metastasize was not modified. Under conditions of increased ERBB2more » oncogenic activity after pregnancy plus SNAI2 deficiency, both pretumoral defects-latency and tumor load-were compensated. However, the incidence of lung metastases was dramatically reduced. Furthermore, SNAI2 was required for proper postlactational involution of the breast. At 3 days post lactational involution, the mammary glands of Snai2-deficient mice exhibited lower levels of pSTAT3 and higher levels of pAKT1, resulting in decreased apoptosis. Abundant noninvoluted ducts were still present at 30 days post lactation, with a greater number of residual ERBB2+ cells. These results suggest that this defect in involution leads to an increase in the number of susceptible target cells for transformation, to the recovery of the capacity to generate mammospheres and to an increase in the number of tumors. In conclusion, our work demonstrates the participation of SNAI2 in the pathogenesis of luminal breast cancer, and reveals an unexpected connection between the processes of postlactational involution and breast tumorigenesis in Snai2-null mutant mice.« less

The SCUBA-2 850 μm Follow-up of WISE-selected, Luminous Dust-obscured Quasars

NASA Astrophysics Data System (ADS)

Fan, Lulu; Jones, Suzy F.; Han, Yunkun; Knudsen, Kirsten K.

2017-12-01

Hot dust-obscured galaxies (Hot DOGs) are a new population recently discovered in the Wide-field Infrared Survey Explorer All-Sky survey. Multiwavelength follow-up observations suggest that they are luminous, dust-obscured quasars at high redshift. Here we present the JCMT SCUBA-2 850 μm follow-up observations of 10 Hot DOGs. Four out of ten Hot DOGs have been detected at >3σ level. Based on the IR SED decomposition approach, we derive the IR luminosities of AGN torus and cold dust components. Hot DOGs in our sample are extremely luminous with most of them having {L}{IR}{tot}> {10}14 {L}⊙ . The torus emissions dominate the total IR energy output. However, the cold dust contribution is still non-negligible, with the fraction of the cold dust contribution to the total IR luminosity (˜8%-24%) being dependent on the choice of torus model. The derived cold dust temperatures in Hot DOGs are comparable to those in UV bright quasars with similar IR luminosity, but much higher than those in SMGs. Higher dust temperatures in Hot DOGs may be due to the more intense radiation field caused by intense starburst and obscured AGN activities. Fourteen and five submillimeter serendipitous sources in the 10 SCUBA-2 fields around Hot DOGs have been detected at >3σ and >3.5σ levels, respectively. By estimating their cumulative number counts, we confirm the previous argument that Hot DOGs lie in dense environments. Our results support the scenario in which Hot DOGs are luminous, dust-obscured quasars lying in dense environments, and being in the transition phase between extreme starburst and UV-bright quasars.

Energy-saving approaches to solid state street lighting

NASA Astrophysics Data System (ADS)

Vitta, Pranciškus; Stanikūnas, Rytis; Tuzikas, Arūnas; Reklaitis, Ignas; Stonkus, Andrius; Petrulis, Andrius; Vaitkevičius, Henrikas; Žukauskas, Artūras

2011-10-01

We consider the energy-saving potential of solid-state street lighting due to improved visual performance, weather sensitive luminance control and tracking of pedestrians and vehicles. A psychophysical experiment on the measurement of reaction time with a decision making task was performed under mesopic levels of illumination provided by a highpressure sodium (HPS) lamp and different solid-state light sources, such as daylight and warm-white phosphor converted light-emitting diodes (LEDs) and red-green-blue LED clusters. The results of the experiment imply that photopic luminances of road surface provided by solid-state light sources with an optimized spectral power distribution might be up to twice as low as those provided by the HPS lamp. Dynamical correction of road luminance against road surface conditions typical of Lithuanian climate was estimated to save about 20% of energy in comparison with constant-level illumination. The estimated energy savings due to the tracking of pedestrians and vehicles amount at least 25% with the cumulative effect of intelligent control of at least 40%. A solid-state street lighting system with intelligent control was demonstrated using a 300 m long test ground consisting of 10 solid-state street luminaires, a meteorological station and microwave motion sensor network operated via power line communication.

The effects of belongingness on the Simultaneous Lightness Contrast: a virtual reality study.

PubMed

Soranzo, Alessandro; Lugrin, Jean-Luc; Wilson, Christopher J

2013-06-28

Simultaneous Lightness Contrast (SLC) is the phenomenon whereby a grey patch on a dark background appears lighter than an equal patch on a light background. Interestingly, the lightness difference between these patches undergoes substantial augmentation when the two backgrounds are patterned, thereby forming the articulated-SLC display. There are two main interpretations of these phenomena: The mid-level interpretation maintains that the visual system groups the luminance within a set of contiguous frameworks, whilst the high-level one claims that the visual system splits the luminance into separate overlapping layers corresponding to separate physical contributions. This research aimed to test these two interpretations by systematically manipulating the viewing distance and the horizontal distance between the backgrounds of both the articulated and plain SLC displays. An immersive 3D Virtual Reality system was employed to reproduce identical alignment and distances, as well as isolating participants from interfering luminance. Results showed that reducing the viewing distance resulted in increased contrast in both the plain- and articulated-SLC displays and that, increasing the horizontal distance between the backgrounds resulted in decreased contrast in the articulated condition but increased contrast in the plain condition. These results suggest that a comprehensive lightness theory should combine the two interpretations. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Luminous flux and illumination

NASA Astrophysics Data System (ADS)

Schröer, H.

2001-06-01

Themes of this book are luminous flux and illumination. The book begins with definitions of the notions luminous flux and solid angle. Then the luminous flux through simple geometrical areas as circle, ball, triangles and n-gons is treated. Chapter 7 deals with luminous flux through general surfaces. A comparison between photometric and radiation dimensions follow. The next chapter contains the luminous flux through simple areas in medium (gas). At last illumination and temperature are presented. The content is interesting for opticians, light technicians and all physicists and natural scientists, who have to do with radiation. There is an english and a german edition.

A young star takes centre stage

NASA Image and Video Library

2015-03-02

With its helical appearance resembling a snail’s shell, this reflection nebula seems to spiral out from a luminous central star in this new NASA/ESA Hubble Space Telescope image. The star in the centre, known as V1331 Cyg and located in the dark cloud LDN 981 — or, more commonly, Lynds 981 — had previously been defined as a T Tauri star. A T Tauri is a young star — or Young Stellar Object — that is starting to contract to become a main sequence star similar to the Sun. What makes V1331Cyg special is the fact that we look almost exactly at one of its poles. Usually, the view of a young star is obscured by the dust from the circumstellar disc and the envelope that surround it. However, with V1331Cyg we are actually looking in the exact direction of a jet driven by the star that is clearing the dust and giving us this magnificent view. This view provides an almost undisturbed view of the star and its immediate surroundings allowing astronomers to study it in greater detail and look for features that might suggest the formation of a verylow-mass object in the outer circumstellar disc.

Energy-saving quality road lighting with colloidal quantum dot nanophosphors

NASA Astrophysics Data System (ADS)

Erdem, Talha; Kelestemur, Yusuf; Soran-Erdem, Zeliha; Ji, Yun; Demir, Hilmi Volkan

2014-12-01

Here the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, specifically in mesopic vision regimes essential to street lighting. Investigating over 100 million designs uncovers that quality road-lighting QD-WLEDs, with a color quality scale and color rendering index ≥85, enables 13-35% higher mesopic luminance than the sources commonly used in street lighting. Furthermore, these QD-WLEDs were shown to be electrically more efficient than conventional sources with power conversion efficiencies ≥16-29%. Considering this fact, an experimental proof-of-concept QD-WLED was demonstrated, which is the first account of QD based color conversion custom designed for street lighting applications. The obtained white LED achieved the targeted mesopic luminance levels in accordance with the road lighting standards of the USA and the UK. These results indicate that road-lighting QD-WLEDs are strongly promising for energy-saving quality road lighting.

The perceptual consequences of interocular suppression in amblyopia.

PubMed

Maehara, Goro; Thompson, Benjamin; Mansouri, Behzad; Farivar, Reza; Hess, Robert F

2011-11-21

It is known that information from an amblyopic eye can be strongly suppressed when both eyes are open. The authors investigated the way in which suppression influences the relative perception of suprathreshold contrast and luminance between a person's eyes under dichoptic viewing conditions. Stimuli consisted of four patches of luminance or four patches containing gratings. Two patches were presented to each eye. Ten amblyopes with mild suppression (six strabismic, three anisometropic and strabismic, and one deprivation; mean age, 34.5 years) and three control observers with normal vision (mean age, 33.0 years) matched the appearance of the stimuli presented to each eye. The match involved manipulation of either luminance or contrast. Amblyopes with mild suppression decreased stimulus luminance in the fellow fixing eye or increased luminance in the amblyopic eye to achieve a match (mean matching luminance, 21.1 and 39.6 cd/m(2) for the fellow fixing eye and the amblyopic eye, respectively; standard luminance, 30 cd/m(2)). This interocular mismatch was also observed when luminance was variable and contrast was kept constant (mean matching luminance, 22.8 cd/m(2) for the fellow fixing eye). On the other hand, the amblyopic eye showed no loss of perceived contrast. There was little or no mismatch between the two eyes of control participants with normal binocular vision. Amblyopes have monocular deficits in contrast perception but dichoptic deficits in luminance perception, suggesting that suppression in its mild form involves luminance processing.

Luminance cues constrain chromatic blur discrimination in natural scene stimuli.

PubMed

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

2013-03-22

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

A model for neutrino emission from nuclear accretion disks

NASA Astrophysics Data System (ADS)

Deaton, Michael

2015-04-01

Compact object mergers involving at least one neutron star can produce short-lived black hole accretion engines. Over tens to hundreds of milliseconds such an engine consumes a disk of hot, nuclear-density fluid, and drives changes to its surrounding environment through luminous emission of neutrinos. The neutrino emission may drive an ultrarelativistic jet, may peel off the disk's outer layers as a wind, may irradiate those winds or other forms of ejecta and thereby change their composition, may change the composition and thermodynamic state of the disk itself, and may oscillate in its flavor content. We present the full spatial-, angular-, and energy-dependence of the neutrino distribution function around a realistic model of a nuclear accretion disk, to inform future explorations of these types of behaviors. Spectral Einstein Code (SpEC).

The nature of the embedded population in the Rho Ophiuchi dark cloud - Mid-infrared observations

NASA Technical Reports Server (NTRS)

Lada, C. J.; Wilking, B. A.

1984-01-01

In combination with previous IR and optical data, the present 10-20 micron observations of previously identified members of the embedded population of the Rho Ophiuchi dark cloud allow determinations to be made of the broadband energy distributions for 32 of the 44 sources. The majority of the sources are found to emit the bulk of their luminosity in the 1-20 micron range, and to be surrounded by dust shells. Because they are, in light of these characteristics, probably premain-sequence in nature, relatively accurate bolometric luminosities for these objects can be obtained through integration of their energy distributions. It is found that 44 percent of the sources are less luminous than the sun, and are among the lowest luminosity premain-sequence/protostellar objects observed to date.

Thackeray's Globules in IC 2944

NASA Technical Reports Server (NTRS)

2002-01-01

Strangely glowing dark clouds float serenely in this remarkable and beautiful image taken with NASA's Hubble Space Telescope. These dense, opaque dust clouds - known as 'globules' - are silhouetted against nearby bright stars in the busy star-forming region, IC 2944. These globules were first found in IC 2944 by astronomer A.D. Thackeray in 1950. Although globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947, little is still known about their origin and nature, except that they are generally associated with areas of star formation, called 'HII regions' due to the presence of hydrogen gas. The largest of the globules in this image is actually two separate clouds that gently overlap along our line of sight. Each cloud is nearly 1.4 light-years (50 arcseconds) along its longest dimension, and collectively, they contain enough material to equal over 15 solar masses. IC 2944, the surrounding HII region, is filled with gas and dust that is illuminated and heated by a loose cluster of O-type stars. These stars are much hotter and much more massive than our Sun. IC 2944 is relatively close by, located only 5900 light-years (1800 parsecs) away in the constellation Centaurus. Thanks to the remarkable resolution offered by the Hubble Space Telescope, astronomers can for the first time study the intricate structure of these globules. The globules appear to be heavily fractured, as if major forces were tearing them apart. When radio astronomers observed the faint hiss of molecules within the globules, they realized that the globules are actually in constant, churning motion, moving supersonically among each other. This may be caused by the powerful ultraviolet radiation from the luminous, massive stars, which also heat up the gas in the HII region, causing it to expand and stream against the globules, leading to their destruction. Despite their serene appearance, the globules may actually be likened to clumps of butter put onto a red-hot pan. It is likely that the globules are dense clumps of gas and dust that existed before the massive O-stars were born. But once these luminous stars began to irradiate and destroy their surroundings, the clumps became visible when their less dense surroundings were eroded away, thus exposing them to the full brunt of the ultraviolet radiation and the expanding HII region. The new images catch a glimpse of the process of destruction. Had the appearance of the luminous O-stars been a bit delayed, it is likely that the clumps would actually have collapsed to form several more low-mass stars like the Sun. Instead they are now being toasted and torn apart. The hydrogen-emission image that clearly shows the outline of the dark globules was taken in February 1999 with Hubble's Wide Field Planetary Camera 2 (WFPC2) by Bo Reipurth (University of Hawaii) and collaborators. Additional broadband images that helped to establish the true color of the stars in the field were taken by the Hubble Heritage Team in February 2001. The composite result is a four-color image of the red, green, blue and H-alpha filters. Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: Bo Reipurth (University of Hawaii)

Neural mechanism for sensing fast motion in dim light.

PubMed

Li, Ran; Wang, Yi

2013-11-07

Luminance is a fundamental property of visual scenes. A population of neurons in primary visual cortex (V1) is sensitive to uniform luminance. In natural vision, however, the retinal image often changes rapidly. Consequently the luminance signals visual cells receive are transiently varying. How V1 neurons respond to such luminance changes is unknown. By applying large static uniform stimuli or grating stimuli altering at 25 Hz that resemble the rapid luminance changes in the environment, we show that approximately 40% V1 cells responded to rapid luminance changes of uniform stimuli. Most of them strongly preferred luminance decrements. Importantly, when tested with drifting gratings, the preferred speeds of these cells were significantly higher than cells responsive to static grating stimuli but not to uniform stimuli. This responsiveness can be accounted for by the preferences for low spatial frequencies and high temporal frequencies. These luminance-sensitive cells subserve the detection of fast motion under the conditions of dim illumination.

Distinguishing Low-Risk Luminal A Breast Cancer Subtypes with Ki-67 and p53 Is More Predictive of Long-Term Survival

PubMed Central

Lee, Se Kyung; Bae, Soo Youn; Lee, Jun Ho; Lee, Hyun-Chul; Yi, Hawoo; Kil, Won Ho; Lee, Jeong Eon; Kim, Seok Won; Nam, Seok Jin

2015-01-01

Overexpression of p53 is the most frequent genetic alteration in breast cancer. Recently, many studies have shown that the expression of mutant p53 differs for each subtype of breast cancer and is associated with different prognoses. In this study, we aimed to determine the suitable cut-off value to predict the clinical outcome of p53 overexpression and its usefulness as a prognostic factor in each subtype of breast cancer, especially in luminal A breast cancer. Approval was granted by the Institutional Review Board of Samsung Medical Center. We analyzed a total of 7,739 patients who were surgically treated for invasive breast cancer at Samsung Medical Center between Dec 1995 and Apr 2013. Luminal A subtype was defined as ER&PR + and HER2- and was further subclassified according to Ki-67 and p53 expression as follows: luminal A (Ki-67-,p53-), luminal A (Ki-67+, p53-), luminal A (Ki-67 -, p53+) and luminal A (Ki-67+, p53+). Low-risk luminal A subtype was defined as negative for both Ki-67 and p53 (luminal A [ki-67-, p53-]), and others subtypes were considered to be high-risk luminal A breast cancer. A cut-off value of 10% for p53 was a good predictor of clinical outcome in all patients and luminal A breast cancer patients. The prognostic role of p53 overexpression for OS and DFS was only significant in luminal A subtype. The combination of p53 and Ki-67 has been shown to have the best predictive power as calculated by the area under curve (AUC), especially for long-term overall survival. In this study, we have shown that overexpression of p53 and Ki-67 could be used to discriminate low-risk luminal A subtype in breast cancer. Therefore, using the combination of p53 and Ki-67 expression in discriminating low-risk luminal A breast cancer may improve the prognostic power and provide the greatest clinical utility. PMID:26241661

Distinguishing Low-Risk Luminal A Breast Cancer Subtypes with Ki-67 and p53 Is More Predictive of Long-Term Survival.

PubMed

Lee, Se Kyung; Bae, Soo Youn; Lee, Jun Ho; Lee, Hyun-Chul; Yi, Hawoo; Kil, Won Ho; Lee, Jeong Eon; Kim, Seok Won; Nam, Seok Jin

2015-01-01

Overexpression of p53 is the most frequent genetic alteration in breast cancer. Recently, many studies have shown that the expression of mutant p53 differs for each subtype of breast cancer and is associated with different prognoses. In this study, we aimed to determine the suitable cut-off value to predict the clinical outcome of p53 overexpression and its usefulness as a prognostic factor in each subtype of breast cancer, especially in luminal A breast cancer. Approval was granted by the Institutional Review Board of Samsung Medical Center. We analyzed a total of 7,739 patients who were surgically treated for invasive breast cancer at Samsung Medical Center between Dec 1995 and Apr 2013. Luminal A subtype was defined as ER&PR + and HER2- and was further subclassified according to Ki-67 and p53 expression as follows: luminal A (Ki-67-,p53-), luminal A (Ki-67+, p53-), luminal A (Ki-67 -, p53+) and luminal A (Ki-67+, p53+). Low-risk luminal A subtype was defined as negative for both Ki-67 and p53 (luminal A [ki-67-, p53-]), and others subtypes were considered to be high-risk luminal A breast cancer. A cut-off value of 10% for p53 was a good predictor of clinical outcome in all patients and luminal A breast cancer patients. The prognostic role of p53 overexpression for OS and DFS was only significant in luminal A subtype. The combination of p53 and Ki-67 has been shown to have the best predictive power as calculated by the area under curve (AUC), especially for long-term overall survival. In this study, we have shown that overexpression of p53 and Ki-67 could be used to discriminate low-risk luminal A subtype in breast cancer. Therefore, using the combination of p53 and Ki-67 expression in discriminating low-risk luminal A breast cancer may improve the prognostic power and provide the greatest clinical utility.

Oviductal morphology in relation to hormonal levels in the snapping turtle, Chelydra serpentina.

PubMed

Alkindi, A Y A; Mahmoud, I Y; Woller, M J; Plude, J L

2006-02-01

Microscopic and in situ visual observations were used to relate circulating hormone levels to morphological changes in the oviduct of the snapping turtle Chelydra serpentina throughout the ovarian cycle. Increase in levels of progesterone (P), estradiol (E2) and testosterone (T) levels coincide with an increase in number and growth of endometrial glands, luminal epithelial cells and secretory droplets throughout the oviduct. Testosterone and estradiol levels rose significantly (P < 0.05) after the May-June period and remained high throughout the rest of the summer. Progesterone levels remained stable throughout the summer, with a brief decline in July due to luteolysis. Hormonal values declined significantly (P < 0.001) at the end of the ovarian cycle in the fall. In situ visual observation of fresh oviducts at different stages of gravidity in recently ovulated turtles revealed that proteinaceous like components from the endometrial glands were released into the lumen to form fibers. The morphological features of the oviduct remained active throughout the summer months even though the snapping turtle is a monoclutch species which deposits all the eggs in late-May to mid-June. The high steroid levels correlate with and may be responsible for the secretory activity present throughout the summer and their decline correlates with change to low secretory activity in the fall. Calcium deposition accompanied by morphological changes in luminal cells are suggestive of secretory activity. In the egg-bearing turtles, uterine Ca2+ concentrations measured by flame atomic absorption spectrophotometry revealed significantly higher Ca2+ concentrations (P < 0.001) in eggs with soft shell than eggs without shell. There was a significant increase in calcium granules and proteinaceous fibers in luminal surface of the uterus during the period of eggshelling. This supports the fact that in the snapping turtle like in other reptiles, eggshelling process occurs in the uterus.

Enteric luminous microflora of the pond-cultured milk fishChanos chanos (Forskal).

PubMed

Ramesh, A; Nandakumar, R; Venugopalan, V K

1986-06-01

Qualitative and quantitative investigations were made on the luminous bacteria associated with the gut of pond cultured milk fishChanos chanos. Significant differences in luminous bacterial numbers were found between gut and pond water and between gut and pond sediment, but not between pond water and sediment. No significant variation in luminous bacterial population among the gut regions was observed. The quantity of ingesta in the fish gut does not appear to influence the biomass of luminous bacteria.Vibrio harveyi andV. fischeri were the 2 most commonly encountered species, and of the 2 luminous species,V. harveyi was predominant.

The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Peng; Li, Jingzhi; Sha, Bingdong

2016-11-29

PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ERmore » stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.« less

The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins.

PubMed

Wang, Peng; Li, Jingzhi; Sha, Bingdong

2016-12-01

PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ER stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.

In Vivo Epithelial Wound Repair Requires Mobilization of Endogenous Intracellular and Extracellular Calcium*

PubMed Central

Aihara, Eitaro; Hentz, Courtney L.; Korman, Abraham M.; Perry, Nicholas P. J.; Prasad, Vikram; Shull, Gary E.; Montrose, Marshall H.

2013-01-01

We report that a localized intracellular and extracellular Ca2+ mobilization occurs at the site of microscopic epithelial damage in vivo and is required to mediate tissue repair. Intravital confocal/two-photon microscopy continuously imaged the surgically exposed stomach mucosa of anesthetized mice while photodamage of gastric epithelial surface cells created a microscopic lesion that healed within 15 min. Transgenic mice with an intracellular Ca2+-sensitive protein (yellow cameleon 3.0) report that intracellular Ca2+ selectively increases in restituting gastric epithelial cells adjacent to the damaged cells. Pretreatment with U-73122, indomethacin, 2-aminoethoxydiphenylborane, or verapamil inhibits repair of the damage and also inhibits the intracellular Ca2+ increase. Confocal imaging of Fura-Red dye in luminal superfusate shows a localized extracellular Ca2+ increase at the gastric surface adjacent to the damage that temporally follows intracellular Ca2+ mobilization. Indomethacin and verapamil also inhibit the luminal Ca2+ increase. Intracellular Ca2+ chelation (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid/acetoxymethyl ester, BAPTA/AM) fully inhibits intracellular and luminal Ca2+ increases, whereas luminal calcium chelation (N-(2-hydroxyetheyl)-ethylendiamin-N,N,N′-triacetic acid trisodium, HEDTA) blocks the increase of luminal Ca2+ and unevenly inhibits late-phase intracellular Ca2+ mobilization. Both modes of Ca2+ chelation slow gastric repair. In plasma membrane Ca-ATPase 1+/− mice, but not plasma membrane Ca-ATPase 4−/− mice, there is slowed epithelial repair and a diminished gastric surface Ca2+ increase. We conclude that endogenous Ca2+, mobilized by signaling pathways and transmembrane Ca2+ transport, causes increased Ca2+ levels at the epithelial damage site that are essential to gastric epithelial cell restitution in vivo. PMID:24121509

In vivo epithelial wound repair requires mobilization of endogenous intracellular and extracellular calcium.

PubMed

Aihara, Eitaro; Hentz, Courtney L; Korman, Abraham M; Perry, Nicholas P J; Prasad, Vikram; Shull, Gary E; Montrose, Marshall H

2013-11-22

We report that a localized intracellular and extracellular Ca(2+) mobilization occurs at the site of microscopic epithelial damage in vivo and is required to mediate tissue repair. Intravital confocal/two-photon microscopy continuously imaged the surgically exposed stomach mucosa of anesthetized mice while photodamage of gastric epithelial surface cells created a microscopic lesion that healed within 15 min. Transgenic mice with an intracellular Ca(2+)-sensitive protein (yellow cameleon 3.0) report that intracellular Ca(2+) selectively increases in restituting gastric epithelial cells adjacent to the damaged cells. Pretreatment with U-73122, indomethacin, 2-aminoethoxydiphenylborane, or verapamil inhibits repair of the damage and also inhibits the intracellular Ca(2+) increase. Confocal imaging of Fura-Red dye in luminal superfusate shows a localized extracellular Ca(2+) increase at the gastric surface adjacent to the damage that temporally follows intracellular Ca(2+) mobilization. Indomethacin and verapamil also inhibit the luminal Ca(2+) increase. Intracellular Ca(2+) chelation (1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxymethyl ester, BAPTA/AM) fully inhibits intracellular and luminal Ca(2+) increases, whereas luminal calcium chelation (N-(2-hydroxyetheyl)-ethylendiamin-N,N,N'-triacetic acid trisodium, HEDTA) blocks the increase of luminal Ca(2+) and unevenly inhibits late-phase intracellular Ca(2+) mobilization. Both modes of Ca(2+) chelation slow gastric repair. In plasma membrane Ca-ATPase 1(+/-) mice, but not plasma membrane Ca-ATPase 4(-/-) mice, there is slowed epithelial repair and a diminished gastric surface Ca(2+) increase. We conclude that endogenous Ca(2+), mobilized by signaling pathways and transmembrane Ca(2+) transport, causes increased Ca(2+) levels at the epithelial damage site that are essential to gastric epithelial cell restitution in vivo.

Influence of background size, luminance and eccentricity on different adaptation mechanisms

PubMed Central

Gloriani, Alejandro H.; Matesanz, Beatriz M.; Barrionuevo, Pablo A.; Arranz, Isabel; Issolio, Luis; Mar, Santiago; Aparicio, Juan A.

2016-01-01

Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06–110 cd/m2) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5 cd/m2. In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range. PMID:27210038

Influence of background size, luminance and eccentricity on different adaptation mechanisms.

PubMed

Gloriani, Alejandro H; Matesanz, Beatriz M; Barrionuevo, Pablo A; Arranz, Isabel; Issolio, Luis; Mar, Santiago; Aparicio, Juan A

2016-08-01

Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06-110cd/m(2)) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5cd/m(2). In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visual acuity measured with luminance-modulated and contrast-modulated noise letter stimuli in young adults and adults above 50 years old

PubMed Central

Woi, Pui Juan; Kaur, Sharanjeet; Waugh, Sarah J.; Hairol, Mohd Izzuddin

2016-01-01

The human visual system is sensitive in detecting objects that have different luminance level from their background, known as first-order or luminance-modulated (LM) stimuli. We are also able to detect objects that have the same mean luminance as their background, only differing in contrast (or other attributes). Such objects are known as second-order or contrast-modulated (CM), stimuli. CM stimuli are thought to be processed in higher visual areas compared to LM stimuli, and may be more susceptible to ageing. We compared visual acuities (VA) of five healthy older adults (54.0±1.83 years old) and five healthy younger adults (25.4±1.29 years old) with LM and CM letters under monocular and binocular viewing. For monocular viewing, age had no effect on VA [F(1, 8)= 2.50, p> 0.05]. However, there was a significant main effect of age on VA under binocular viewing [F(1, 8)= 5.67, p< 0.05].  Binocular VA with CM letters in younger adults was approximately two lines better than that in older adults. For LM, binocular summation ratios were similar for older (1.16±0.21) and younger (1.15±0.06) adults. For CM, younger adults had higher binocular summation ratio (1.39±0.08) compared to older adults (1.12±0.09). Binocular viewing improved VA with LM letters for both groups similarly. However, in older adults, binocular viewing did not improve VA with CM letters as much as in younger adults. This could reflect a decline of higher visual areas due to ageing process, most likely higher than V1, which may be missed if measured with luminance-based stimuli alone. PMID:28184281

High power LED standard light sources for photometric applications

NASA Astrophysics Data System (ADS)

Ivashin, Evgeniy; Ogarev, Sergey; Khlevnoy, Boris; Shirokov, Stanislav; Dobroserdov, Dmitry; Sapritsky, Victor

2018-02-01

High power LED light sources have been developed as possible new VNIIOFI standard sources for luminous intensity, luminous flux and colour measurements. Stability, repeatability and spatial uniformity of the sources were investigated and demonstrated high accuracy and homogeneity. The paper describes different tests on one of the manufactured sources. In the future, these LED light sources are planned to be used as standard luminous flux sources to transfer the units of luminous intensity and luminous flux from gonio-spectrometer to sphere-spectrometer.

Evaluation of True Power Luminous Efficiency from Experimental Luminance Values

NASA Astrophysics Data System (ADS)

Tsutsui, Tetsuo; Yamamato, Kounosuke

1999-05-01

A method for obtaining true external power luminous efficiencyfrom experimentally obtained luminance in organic light-emittingdiodes (LEDs) wasdemonstrated. Conventional two-layer organic LEDs with different electron-transport layer thicknesses wereprepared. Spatial distributions of emission intensities wereobserved. The large deviation in both emission spectra and spatialemission patterns were observed when the electron-transport layerthickness was varied. The deviation of emission patterns from thestandard Lambertian pattern was found to cause overestimations ofpower luminous efficiencies as large as 30%. A method for evaluatingcorrection factors was proposed.

Large-scale clustering of Lymanα emission intensity from SDSS/BOSS

DOE PAGES

Croft, Rupert A. C.; Miralda-Escudé, Jordi; Zheng, Zheng; ...

2016-01-27

Here we present a tentative detection of the large-scale structure of Ly α emission in the Universe at redshifts z = 2–3.5 by measuring the cross-correlation of Ly α surface brightness with quasars in Sloan Digital Sky Survey/Baryon Oscillation Spectroscopic Survey. We use a million spectra targeting luminous red galaxies at z < 0.8, after subtracting a best-fitting model galaxy spectrum from each one, as an estimate of the high-redshift Ly α surface brightness. The quasar–Ly α emission cross-correlation is detected on scales 1 ~ 15h ₋1 Mpc, with shape consistent with a ΛCDM model with Ω m =0.30± 0.10more » 0.07. The predicted amplitude of this cross- correlation is proportional to the product of the mean Lyα surface brightness, {μ α}, the amplitude of mass density fluctuations, and the quasar and Lyα emission bias factors. Using published cosmological observations to constrain the amplitude of mass fluctuations and the quasar bias factor, we infer the value of the product {μ α} (b α /3) = (3.9±0.9)×10 ₋21 erg s ₋1 cm ₋2 °A ₋1 arcsec ₋2, where b α is the Lyα emission linear bias factor. If the dominant sources of Lyα emission we measure are star forming galaxies, we infer a total mean star formation rate density of ρSFR = (0.28 ± 0.07)(3/b α ) yr ₋1 Mpc ₋3 at z = 2 ₋ 3.5. For b α = 3, this value is a factor of 21 ₋ 35 above previous estimates relying on individually detected Lyα emitters, although it is consistent with the total star-formation density derived from dust-corrected, continuum UV surveys. Our observations therefore imply that 97% of the Lyα emission in the Universe at these redshifts is undetected in previous surveys of Lyα emitters. Our detected Lyα emission is also much greater, by at least an order of magnitude, than that measured from stacking analyses of faint halos surrounding previously detected Lyα emitters, but we speculate that it arises from similar low surface brightness Lyα halos surrounding all luminous star-forming galaxies. We also detect a redshift space anisotropy of the quasar-Lyα emission cross-correlation, finding evidence at the 3.0σ level that it is radially elongated, contrary to the prediction for linear gravitational evolution, but consistent with distortions caused by radiative-transfer effects, as predicted by Zheng et al. (2011). Lastly, our measurements represent the first application of the intensity mapping technique to optical observations.« less

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

PubMed

Cooper, Bonnie; Lee, Barry B

2014-04-01

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

An empirical study of the nuclear explosion-induced lightning seen on IVY-MIKE

NASA Astrophysics Data System (ADS)

Colvin, J. D.; Mitchell, C. K.; Greig, J. R.; Murphy, D. P.; Pechacek, R. E.; Raleigh, M.

1987-05-01

We report the results of a unique study of the lightninglike phenomena that were seen to accompany the MIKE shot of operation IVY on October 31 1952. MIKE was a thermonuclear surface burst yielding 10.4 MT, which took place on Enewetak Atoll. During the period of approximately 10 ms after detonation, five discrete luminous channels were seen to start from the ground or sea surface at a distance of approximately 1 km from the burst point and to grow up into the clouds. We have reexamined the original photographic records of IVY-MIKE, obtaining effective brightnesses (optical powers per unit length) for the luminous channels at different altitudes as functions of time. The absolute calibration for the MIKE records was deduced by comparison with the photographic records of other events of that era, laboratory measurements of film sensitivity, and use of atmospheric transmission data taken just prior to the MIKE event. Errors in this analysis lead to an uncertainty of a factor of ˜2 in the brightnesses of the luminous channels. In the laboratory we have used laser-guided electric discharges to create long (100 cm), arclike plasma channels to simulate the observed luminous channels and to allow determination of an empirical relation between the brightness of the channel and the electric current flowing in the channel. These laboratory discharges had peak currents up to 100 kA and periods of ˜2 ms. Spectroscopic analysis showed that the luminous channels consisted primarily of normal air plasma with typical ground-level contaminants. Photographic studies showed that these long-duration discharges are unstable to the m = 1 magnetohydrodynamic (MHD) instability and become severely distorted in less than 1 ms. By direct comparison of the luminous channels seen at MIKE and the laboratory discharges, we deduce: (1) the peak current in the prominent (brightest) channel at MIKE was between 200 and 600 kA. Here the most likely value of the peak current was 250±50 kA, but potential systematic errors in the film calibration and the comparison of MIKE and laboratory data make higher currents possible. (2) The rapid decline in the brightness of the luminous channels seen at MIKE is caused by a combination of the effects of the MHD instability, which eventually leads to a broadening of the current-carrying channel, and channel cooling by turbulent convective mixing.

An unbiased measure of the contributions of chroma and luminance to saccadic suppression of displacement.

PubMed

Anand, Sulekha; Bridgeman, Bruce

2002-02-01

Perception of image displacement is suppressed during saccadic eye movements. We probed the source of saccadic suppression of displacement by testing whether it selectively affects chromatic- or luminance-based motion information. Human subjects viewed a stimulus in which chromatic and luminance cues provided conflicting information about displacement direction. Apparent motion occurred during either fixation or a 19.5 degree saccade. Subjects detected motion and discriminated displacement direction in each trial. They reported motion in over 90% of fixation trials and over 70% of saccade trials. During fixation, the probability of perceiving the direction carried by chromatic cues decreased as luminance contrast increased. During saccades, subjects tended to perceive the direction indicated by luminance cues when luminance contrast was high. However, when luminance contrast was low, subjects showed no preference for the chromatic- or luminance-based direction. Thus magnocellular channels are suppressed, while stimulation of parvocellular channels is below threshold, so that neither channel drives motion perception during saccades. These results confirm that magnocellular inhibition is the source of saccadic suppression.

Chronic shear induces caveolae formation and alters ERK and Akt responses in endothelial cells

NASA Technical Reports Server (NTRS)

Boyd, Nolan L.; Park, Heonyong; Yi, Hong; Boo, Yong Chool; Sorescu, George P.; Sykes, Michelle; Jo, Hanjoong

2003-01-01

Caveolae are plasmalemmal domains enriched with cholesterol, caveolins, and signaling molecules. Endothelial cells in vivo are continuously exposed to shear conditions, and their caveolae density and location may be different from that of static cultured cells. Here, we show that chronic shear exposure regulates formation and localization of caveolae and caveolin-1 in bovine aortic endothelial cells (BAEC). Chronic exposure (1 or 3 days) of BAEC to laminar shear increased the total number of caveolae by 45-48% above static control. This increase was due to a rise in the luminal caveolae density without changing abluminal caveolae numbers or increasing caveolin-1 mRNA and protein levels. Whereas some caveolin-1 was found in the plasma membrane in static-cultured cells, it was predominantly localized in the Golgi. In contrast, chronic shear-exposed cells showed intense caveolin-1 staining in the luminal plasma membrane with minimum Golgi association. The preferential luminal localization of caveolae may play an important role in endothelial mechanosensing. Indeed, we found that chronic shear exposure (preconditioning) altered activation patterns of two well-known shear-sensitive signaling molecules (ERK and Akt) in response to a step increase in shear stress. ERK activation was blunted in shear preconditioned cells, whereas the Akt response was accelerated. These results suggest that chronic shear stimulates caveolae formation by translocating caveolin-1 from the Golgi to the luminal plasma membrane and alters cell signaling responses.

Cytochemical analysis of alkaline phosphatase and esterase activities and of lectin-binding and anionic sites in rat and mouse Peyer's patch M cells.

PubMed

Owen, R L; Bhalla, D K

1983-10-01

M cells in Peyer's patch follicle epithelium endocytose and transport luminal materials to intraepithelial lymphocytes. We examined (1) enzymatic characteristics of the epithelium covering mouse and rat Peyer's patches by using cytochemical techniques, (2) distribution of lectin-binding sites by peroxidase-labeled lectins, and (3) anionic site distribution by using cationized ferritin to develop a profile of M cell surface properties. Alkaline phosphatase activity resulted in deposits of dense reaction product over follicle surfaces but was markedly reduced over M cells, unlike esterase which formed equivalent or greater product over M cells. Concanavalin A, ricinus communis agglutinin, wheat germ agglutinin and peanut agglutinin reacted equally with M cells and with surrounding enterocytes over follicle surfaces. Cationized ferritin distributed in a random fashion along microvillus membranes of both M cells and enterocytes, indicating equivalent anionic site distribution. Staining for alkaline phosphatase activity provides a new approach for distinguishing M cells from enterocytes at the light microscopic level. Identical binding of lectins indicates that M cells and enterocytes share common glycoconjugates even though molecular groupings may differ. Lectin binding and anionic charge similarities of M cells and enterocytes may facilitate antigen sampling by M cells of particles and compounds that adhere to intestinal surfaces in non-Peyer's patch areas.

TFAP2C governs the luminal epithelial phenotype in mammary development and carcinogenesis.

PubMed

Cyr, A R; Kulak, M V; Park, J M; Bogachek, M V; Spanheimer, P M; Woodfield, G W; White-Baer, L S; O'Malley, Y Q; Sugg, S L; Olivier, A K; Zhang, W; Domann, F E; Weigel, R J

2015-01-22

Molecular subtypes of breast cancer are characterized by distinct patterns of gene expression that are predictive of outcome and response to therapy. The luminal breast cancer subtypes are defined by the expression of estrogen receptor-alpha (ERα)-associated genes, many of which are directly responsive to the transcription factor activator protein 2C (TFAP2C). TFAP2C participates in a gene regulatory network controlling cell growth and differentiation during ectodermal development and regulating ESR1/ERα and other luminal cell-associated genes in breast cancer. TFAP2C has been established as a prognostic factor in human breast cancer, however, its role in the establishment and maintenance of the luminal cell phenotype during carcinogenesis and mammary gland development have remained elusive. Herein, we demonstrate a critical role for TFAP2C in maintaining the luminal phenotype in human breast cancer and in influencing the luminal cell phenotype during normal mammary development. Knockdown of TFAP2C in luminal breast carcinoma cells induced epithelial-mesenchymal transition with morphological and phenotypic changes characterized by a loss of luminal-associated gene expression and a concomitant gain of basal-associated gene expression. Conditional knockout of the mouse homolog of TFAP2C, Tcfap2c, in mouse mammary epithelium driven by MMTV-Cre promoted aberrant growth of the mammary tree leading to a reduction in the CD24(hi)/CD49f(mid) luminal cell population and concomitant gain of the CD24(mid)/CD49f(hi) basal cell population at maturity. Our results establish TFAP2C as a key transcriptional regulator for maintaining the luminal phenotype in human breast carcinoma. Furthermore, Tcfap2c influences development of the luminal cell type during mammary development. The data suggest that TFAP2C has an important role in regulated luminal-specific genes and may be a viable therapeutic target in breast cancer.

Luminance-model-based DCT quantization for color image compression

NASA Technical Reports Server (NTRS)

Ahumada, Albert J., Jr.; Peterson, Heidi A.

1992-01-01

A model is developed to approximate visibility thresholds for discrete cosine transform (DCT) coefficient quantization error based on the peak-to-peak luminance of the error image. Experimentally measured visibility thresholds for R, G, and B DCT basis functions can be predicted by a simple luminance-based detection model. This model allows DCT coefficient quantization matrices to be designed for display conditions other than those of the experimental measurements: other display luminances, other veiling luminances, and other spatial frequencies (different pixel spacings, viewing distances, and aspect ratios).

Highly efficient inverted organic light emitting diodes by inserting a zinc oxide/polyethyleneimine (ZnO:PEI) nano-composite interfacial layer

NASA Astrophysics Data System (ADS)

Kaçar, Rifat; Pıravadılı Mucur, Selin; Yıldız, Fikret; Dabak, Salih; Tekin, Emine

2017-06-01

The electrode/organic interface is one of the key factors in attaining superior device performance in organic electronics, and inserting a tailor-made layer can dramatically modify its properties. The use of nano-composite (NC) materials leads to many advantages by combining materials with the objective of obtaining a desirable combination of properties. In this context, zinc oxide/polyethyleneimine (ZnO:PEI) NC film was incorporated as an interfacial layer into inverted bottom-emission organic light emitting diodes (IBOLEDs) and fully optimized. For orange-red emissive MEH-PPV based IBOLEDs, a high power efficiency of 6.1 lm W-1 at a luminance of 1000 cd m-2 has been achieved. Notably, the external quantum efficiency (EQE) increased from 0.1 to 4.8% and the current efficiency (CE) increased from 0.2 to 8.7 cd A-1 with rise in luminance (L) from 1000 to above 10 000 cd m-2 levels when compared to that of pristine ZnO-based devices. An identical device architecture containing a ZnO:PEI NC layer has also been used to successfully fabricate green and blue emissive IBOLEDs. The significant enhancement in the inverted device performance, in terms of luminance and efficiency, is attributed to a good energy-level alignment between the cathode/organic interface which leads to effective carrier balance, resulting in efficient radiative-recombination.

Performance of 'energy efficient' compact fluorescent lamps.

PubMed

Yuen, Gloria S-C; Sproul, Alistair B; Dain, Stephen J

2010-03-01

Compact fluorescent lamps (CFLs) have been heralded as highly energy efficient replacements for incandescent light globes, however, there is some public dissatisfaction with the light output and colour of CFLs. Independent examination of the claims made has not been made. Compliance with the interim Australian/New Zealand Standard has not been established by any independent authority. While the total light output (luminous flux) may meet certain standards, luminous intensity distributions of some designs do differ significantly from the incandescent sources that they are intended to replace. Luminous intensity distribution, luminous flux and spectral energy distribution of CFLs claimed to be equivalent to 75 W incandescent globes and 75 W incandescent globes (pearl and clear) were measured. Luminous flux, luminous efficacy, colour rendering index, correlated colour temperature, wattage and power factor were then calculated and compared with claims made by manufacturers and requirements of the standards. The sources generally complied with the requirements for luminous flux, luminous efficacy, colour rendering index and correlated colour temperature. The claim of 75 W equivalence, which is not regulated in Australia and New Zealand, is justified less than half the time. Luminous intensity distributions of biaxial CFLs are distinctly different from the incandescent lamps they purport to replace. CFLs generally comply with the standards set. The basis on which equivalent wattages are claimed needs to be included in the Australian and New Zealand standard because this is the measure most likely to be relied on by the public. Due to the differences in luminous intensity distribution, CFLs may not necessarily be a direct replacement for incandescent sources without some consideration.

An in vitro methodology for forecasting luminal concentrations and precipitation of highly permeable lipophilic weak bases in the fasted upper small intestine.

PubMed

Psachoulias, Dimitrios; Vertzoni, Maria; Butler, James; Busby, David; Symillides, Moira; Dressman, Jennifer; Reppas, Christos

2012-12-01

To develop an in vitro methodology for prediction of concentrations and potential precipitation of highly permeable, lipophilic weak bases in fasted upper small intestine based on ketoconazole and dipyridamole luminal data. Evaluate usefulness of methodology in predicting luminal precipitation of AZD0865 and SB705498 based on plasma data. A three-compartment in vitro setup was used. Depending on the dosage form administered in in vivo studies, a solution or a suspension was placed in the gastric compartment. A medium simulating the luminal environment (FaSSIF-V2plus) was initially placed in the duodenal compartment. Concentrated FaSSIF-V2plus was placed in the reservoir compartment. In vitro ketoconazole and dipyridamole concentrations and precipitated fractions adequately reflected luminal data. Unlike luminal precipitates, in vitro ketoconazole precipitates were crystalline. In vitro AZD0865 data confirmed previously published human pharmacokinetic data suggesting that absorption rates are not affected by luminal precipitation. In vitro SB705498 data predicted that significant luminal precipitation occurs after a 100 mg or 400 mg but not after a 10 mg dose, consistent with human pharmacokinetic data. An in vitro methodology for predicting concentrations and potential precipitation in fasted upper small intestine, after administration of highly permeable, lipophilic weak bases in fasted upper small intestine was developed and evaluated for its predictability in regard to luminal precipitation.

Glare effect for three types of street lamps based on White LEDs

NASA Astrophysics Data System (ADS)

Sun, Ching-Cherng; Jiang, Chong-Jhih; Chen, Yi-Chun; Yang, Tsung-Hsun

2014-05-01

This study is aimed to assess the glare effect from LED-based street lamps with three general optical designs, which are cluster LEDs with a single lens, a LED array accompany with a lens array, and a tilted LED array, respectively. Observation conditions were simulated based on various locations and viewing axes. Equivalent luminance calculations were used to reveal the glare levels of the three designs. The age effect for the calculated equivalent luminance was also examined for human eyes of people at the age of 40 or 60. The results demonstrate that among the three design types, a LED array accompany with a lens array causes relatively smaller glare for most viewing conditions.

Integration of organic LEDs with inorganic LEDs for a hybrid lighting system

NASA Astrophysics Data System (ADS)

Kong, H. J.; Park, J. W.; Kim, Y. M.

2013-01-01

We demonstrate that a surface-emitting hybrid light source can be realized by a combination of organic and inorganic light-emitting devices (LEDs). To this end, a blue inorganic LED bar is deployed at one side of a transparent light guide plate (LGP), and a yellow organic LED (OLED) is in contact with the rear surface of the LGP. In such a configuration, it is found that the overall luminance is almost equivalent to the sum of the luminances measured from each light source, and the overall luminance uniformity is determined mainly by the luminance uniformity of the OLED panel at high luminances. We have achieved a white color showing the Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (x = 0.34, y = 0.33), the power efficiency of 9.3 lm/W, the luminance uniformity of 63% at the luminance of 3100 cd m-2, the color rendering index as high as 89.3, and the correlated color temperature finely tunable within the range between 3000 and 8000 K. Such a system facilitates color tuning by adjusting their luminous intensities and hence the implementation of the emotional lighting system.

Esophageal luminal stenosis is an independent prognostic factor in esophageal squamous cell carcinoma.

PubMed

Yang, Yu-Shang; Hu, Wei-Peng; Ni, Peng-Zhi; Wang, Wen-Ping; Yuan, Yong; Chen, Long-Qi

2017-06-27

Predictive value of preoperative endoscopic characteristic of esophageal tumor has not been fully evaluated. The aim of this study is to investigate the impact of esophageal luminal stenosis on survival for patients with resectable esophageal squamous cell carcinoma (ESCC). The clinicopathologic characteristics of 623 ESCC patients who underwent curative resection as the primary treatment between January 2005 and April 2009 were retrospectively reviewed. The esophageal luminal stenosis measured by endoscopy was defined as a uniform measurement preoperatively. The impact of esophageal luminal stenosis on patients' overall survival (OS) and relation with other clinicopathological features were assessed. A Cox regression model was used to identify prognostic factors. The results showed that OS significantly decreased in patients with manifest stenotic tumor compared with patients without luminal obstruction (P<0.05). Considerable esophageal luminal stenosis was associated with a higher T stage, longer tumor length, and poorer differentiation (all P<0.05). In multivariate survival analysis, esophageal luminal stenosis remained as an independent prognostic factor for OS (P= 0.036). Esophageal luminal stenosis could have a significant impact on the OS in patients with resected ESCC and may provide additional prognostic value to the current staging system before any cancer-specific treatment.

Survey of discomfort glare from the headlamps of cars widely used in Iran.

PubMed

Mehri, Ahmad; Farhang Dehghan, Somayeh; Hajizadeh, Roohalah; Zakerian, Seyed Abolfazl; Mohammadi, Hamzeh; Abbasi, Milad

2017-10-03

On 2-lane roads, discomfort glare can cause annoyance, discomfort, inconvenience, stress, and fatigue to drivers, posing a risk of accidents. The aim of this study is to evaluate discomfort glare from the headlamps of cars widely used in Iran. The discomfort glare of new vehicles including Pride Saba model GTX, Pride Model 131SL, Samand Soren, Peugeot 405, Megane, and Peugeot Pars was examined at distances of 5 to 100 m at a background luminance of 50 cd/m 2 (late twilight/early dawn lighting) and 1 cd/m 2 (nighttime) using Schmidt-Clausen and Bindels model and de Boer's subjective scale. According to the de Boer scale, at a background luminance of 50 cd/m 2 , the discomfort glare for all studied vehicles was between 1.98 and 4.05 in high-beam mode and between 3.5 and 5.4 in low-beam mode. At a background luminance of 1 cd/m 2 , discomfort glare was between 0.41 and 2.48 in high-beam mode and between 1.93 and 3.84 in low-beam mode. In high-beam mode, the average levels of discomfort glare of these vehicles gradually increased when the distance between cars was reduced by up to about 20 m. In low-beam mode, there was no discomfort glare up to a vehicle distance of 40 m. In addition, at an angle of 1.15°-5.73° between the line of sight and light of vehicles in high-beam mode, the level of discomfort glare was increased, but at an angle of 5.73°-22.9° the level of discomfort glare was reduced. In low-beam mode at an angle of 2.86°-22.9°, the level of discomfort glare was almost identical. The results show that in high-beam mode and with a 100-m distance between vehicles as well as in low-beam mode at intervals of less than 40 m between cars, discomfort glare is created. It can be concluded that by providing solutions such as installing road lighting system, an increase in luminance of roads, separating or widening road lanes, increasing the lateral distance between vehicles, and increasing the angle between lighted vehicles and drivers can noticeably reduce discomfort glare.

Competition between color and luminance for target selection in smooth pursuit and saccadic eye movements.

PubMed

Spering, Miriam; Montagnini, Anna; Gegenfurtner, Karl R

2008-11-24

Visual processing of color and luminance for smooth pursuit and saccadic eye movements was investigated using a target selection paradigm. In two experiments, stimuli were varied along the dimensions color and luminance, and selection of the more salient target was compared in pursuit and saccades. Initial pursuit was biased in the direction of the luminance component whereas saccades showed a relative preference for color. An early pursuit response toward luminance was often reversed to color by a later saccade. Observers' perceptual judgments of stimulus salience, obtained in two control experiments, were clearly biased toward luminance. This choice bias in perceptual data implies that the initial short-latency pursuit response agrees with perceptual judgments. In contrast, saccades, which have a longer latency than pursuit, do not seem to follow the perceptual judgment of salience but instead show a stronger relative preference for color. These substantial differences in target selection imply that target selection processes for pursuit and saccadic eye movements use distinctly different weights for color and luminance stimuli.

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

PubMed

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

2012-02-01

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

Color and luminance in the perception of 1- and 2-dimensional motion.

PubMed

Farell, B

1999-08-01

An isoluminant color grating usually appears to move more slowly than a luminance grating that has the same physical speed. Yet a grating defined by both color and luminance is seen as perceptually unified and moving at a single intermediate speed. In experiments measuring perceived speed and direction, it was found that color- and luminance-based motion signals are combined differently in the perception of 1-D motion than they are in the perception of 2-D motion. Adding color to a moving 1-D luminance pattern, a grating, slows its perceived speed. Adding color to a moving 2-D luminance pattern, a plaid made of orthogonal gratings, leaves its perceived speed unchanged. Analogous results occur for the perception of the direction of 2-D motion. The visual system appears to discount color when analyzing the motion of luminance-bearing 2-D patterns. This strategy has adaptive advantages, making the sensing of object motion more veridical without sacrificing the ability to see motion at isoluminance.

Luminal epithelial cells within the mammary gland can produce basal cells upon oncogenic stress.

PubMed

Hein, S M; Haricharan, S; Johnston, A N; Toneff, M J; Reddy, J P; Dong, J; Bu, W; Li, Y

2016-03-17

In the normal mammary gland, the basal epithelium is known to be bipotent and can generate either basal or luminal cells, whereas the luminal epithelium has not been demonstrated to contribute to the basal compartment in an intact and normally developed mammary gland. It is not clear whether cellular heterogeneity within a breast tumor results from transformation of bipotent basal cells or from transformation and subsequent basal conversion of the more differentiated luminal cells. Here we used a retroviral vector to express an oncogene specifically in a small number of the mammary luminal epithelial cells and tested their potential to produce basal cells during tumorigenesis. This in-vivo lineage-tracing work demonstrates that luminal cells are capable of producing basal cells on activation of either polyoma middle T antigen or ErbB2 signaling. These findings reveal the plasticity of the luminal compartment during tumorigenesis and provide an explanation for cellular heterogeneity within a cancer.

Luminal Epithelial Cells within the Mammary Gland Can Produce Basal Cells upon Oncogenic Stress

PubMed Central

Hein, Sarah M.; Haricharan, Svasti; Johnston, Alyssa N.; Toneff, Michael J.; Reddy, Jay P.; Dong, Jie; Bu, Wen; Li, Yi

2015-01-01

In the normal mammary gland, the basal epithelium is known to be bi-potent and can generate either basal or luminal cells, whereas the luminal epithelium has not been demonstrated to contribute to the basal compartment in an intact and normally developed mammary gland. It is not clear whether cellular heterogeneity within a breast tumor results from transformation of bi-potent basal cells or from transformation and subsequent basal conversion of the more differentiated luminal cells. Here, we used a retroviral vector to express an oncogene specifically in a small number of the mammary luminal epithelial cells and tested their potential to produce basal cells during tumorigenesis. This in vivo lineage tracing work demonstrates that luminal cells are capable of producing basal cells upon activation of either Polyoma Middle T antigen (PyMT) or ErbB2 signaling. These findings reveal the plasticity of the luminal compartment during tumorigenesis and provide an explanation for cellular heterogeneity within a cancer. PMID:26096929

Genomic and Phylogenetic Characterization of Luminous Bacteria Symbiotic with the Deep-Sea Fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae)

PubMed Central

Dunlap, Paul V.; Ast, Jennifer C.

2005-01-01

Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040T, and the type strain of Photobacterium iliopiscarium, ATCC 51760T. Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040T. These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of luminous bacteria, form a clade, designated the kishitanii clade, that is related to but evolutionarily distinct from P. phosphoreum. Members of the kishitanii clade may constitute the major or sole bioluminescent symbiont of several families of deep-sea luminous fishes. PMID:15691950

Genomic and phylogenetic characterization of luminous bacteria symbiotic with the deep-sea fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae).

PubMed

Dunlap, Paul V; Ast, Jennifer C

2005-02-01

Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of luminous bacteria, form a clade, designated the kishitanii clade, that is related to but evolutionarily distinct from P. phosphoreum. Members of the kishitanii clade may constitute the major or sole bioluminescent symbiont of several families of deep-sea luminous fishes.

Effect of glare on simple reaction time.

PubMed

Aguirre, Rolando C; Colombo, Elisa M; Barraza, José F

2008-07-01

We systematized the study of the effect of glare on reaction time (RT), for visual conditions similar to the ones found during night driving: Mesopic range of adaptation (0.14 cd/m2), glare levels of the order of those produced by car headlights (E(G)=15, 60 lx), suprathreshold luminance contrasts, and a variety of spatial frequencies covering the selected range of visibility (1, 2, 4, and 8 c/deg). We found that for the no-glare situation, RT increases with decreasing contrast and increasing spatial frequency, which agrees with previous findings. When data are plotted as a function of the inverse of contrast, RT varies linearly, with k--the RT-contrast factor of Pieron's law--representing the slope of the lines. The effect of glare on RT is an increase in the slope of these lines. This effect is different for each spatial frequency, which cannot be accounted for in the classic approach considering that glare can be replaced by a single veiling luminance. We show that the effect of glare on RT must be modeled by an equivalent glare luminance that depends on spatial frequency.

Pupil size reflects the focus of feature-based attention.

PubMed

Binda, Paola; Pereverzeva, Maria; Murray, Scott O

2014-12-15

We measured pupil size in adult human subjects while they selectively attended to one of two surfaces, bright and dark, defined by coherently moving dots. The two surfaces were presented at the same location; therefore, subjects could select the cued surface only on the basis of its features. With no luminance change in the stimulus, we find that pupil size was smaller when the bright surface was attended and larger when the dark surface was attended: an effect of feature-based (or surface-based) attention. With the same surfaces at nonoverlapping locations, we find a similar effect of spatial attention. The pupil size modulation cannot be accounted for by differences in eye position and by other variables known to affect pupil size such as task difficulty, accommodation, or the mere anticipation (imagery) of bright/dark stimuli. We conclude that pupil size reflects not just luminance or cognitive state, but the interaction between the two: it reflects which luminance level in the visual scene is relevant for the task at hand. Copyright © 2014 the American Physiological Society.

Calsequestrin mediates changes in spontaneous calcium release profiles.

PubMed

Tania, Nessy; Keener, James P

2010-08-07

Calsequestrin (CSQ) is the primary calcium buffer within the sarcoplasmic reticulum (SR) of cardiac cells. It has also been identified as a regulator of Ryanodine receptor (RyR) calcium release channels by serving as a SR luminal sensor. When calsequestrin is free and unbound to calcium, it can bind to RyR and desensitize the channel from cytoplasmic calcium activation. In this paper, we study the role of CSQ as a buffer and RyR luminal sensor using a mechanistic model of RyR-CSQ interaction. By using various asymptotic approximations and mean first exit time calculation, we derive a minimal model of a calcium release unit which includes CSQ dependence. Using this model, we then analyze the effect of changing CSQ expression on the calcium release profile and the rate of spontaneous calcium release. We show that because of its buffering capability, increasing CSQ increases the spark duration and size. However, because of luminal sensing effects, increasing CSQ depresses the basal spark rate and increases the critical SR level for calcium release termination. Finally, we show that with increased bulk cytoplasmic calcium concentration, the CRU model exhibits deterministic oscillations.

Single sensor processing to obtain high resolution color component signals

NASA Technical Reports Server (NTRS)

Glenn, William E. (Inventor)

2010-01-01

A method for generating color video signals representative of color images of a scene includes the following steps: focusing light from the scene on an electronic image sensor via a filter having a tri-color filter pattern; producing, from outputs of the sensor, first and second relatively low resolution luminance signals; producing, from outputs of the sensor, a relatively high resolution luminance signal; producing, from a ratio of the relatively high resolution luminance signal to the first relatively low resolution luminance signal, a high band luminance component signal; producing, from outputs of the sensor, relatively low resolution color component signals; and combining each of the relatively low resolution color component signals with the high band luminance component signal to obtain relatively high resolution color component signals.

Quantification of cuttlefish (Sepia officinalis) camouflage: a study of color and luminance using in situ spectrometry.

PubMed

Akkaynak, Derya; Allen, Justine J; Mäthger, Lydia M; Chiao, Chuan-Chin; Hanlon, Roger T

2013-03-01

Cephalopods are renowned for their ability to adaptively camouflage on diverse backgrounds. Sepia officinalis camouflage body patterns have been characterized spectrally in the laboratory but not in the field due to the challenges of dynamic natural light fields and the difficulty of using spectrophotometric instruments underwater. To assess cuttlefish color match in their natural habitats, we studied the spectral properties of S. officinalis and their backgrounds on the Aegean coast of Turkey using point-by-point in situ spectrometry. Fifteen spectrometry datasets were collected from seven cuttlefish; radiance spectra from animal body components and surrounding substrates were measured at depths shallower than 5 m. We quantified luminance and color contrast of cuttlefish components and background substrates in the eyes of hypothetical di- and trichromatic fish predators. Additionally, we converted radiance spectra to sRGB color space to simulate their in situ appearance to a human observer. Within the range of natural colors at our study site, cuttlefish closely matched the substrate spectra in a variety of body patterns. Theoretical calculations showed that this effect might be more pronounced at greater depths. We also showed that a non-biological method ("Spectral Angle Mapper"), commonly used for spectral shape similarity assessment in the field of remote sensing, shows moderate correlation to biological measures of color contrast. This performance is comparable to that of a traditional measure of spectral shape similarity, hue and chroma. This study is among the first to quantify color matching of camouflaged cuttlefish in the wild.

A numerical experiment on light pollution from distant sources

NASA Astrophysics Data System (ADS)

Kocifaj, M.

2011-08-01

To predict the light pollution of the night-time sky realistically over any location or measuring point on the ground presents quite a difficult calculation task. Light pollution of the local atmosphere is caused by stray light, light loss or reflection of artificially illuminated ground objects or surfaces such as streets, advertisement boards or building interiors. Thus it depends on the size, shape, spatial distribution, radiative pattern and spectral characteristics of many neighbouring light sources. The actual state of the atmospheric environment and the orography of the surrounding terrain are also relevant. All of these factors together influence the spectral sky radiance/luminance in a complex manner. Knowledge of the directional behaviour of light pollution is especially important for the correct interpretation of astronomical observations. From a mathematical point of view, the light noise or veil luminance of a specific sky element is given by a superposition of scattered light beams. Theoretical models that simulate light pollution typically take into account all ground-based light sources, thus imposing great requirements on CPU and MEM. As shown in this paper, a contribution of distant sources to the light pollution might be essential under specific conditions of low turbidity and/or Garstang-like radiative patterns. To evaluate the convergence of the theoretical model, numerical experiments are made for different light sources, spectral bands and atmospheric conditions. It is shown that in the worst case the integration limit is approximately 100 km, but it can be significantly shortened for light sources with cosine-like radiative patterns.

Lasers' spectral and temporal profile can affect visual glare disability.

PubMed

Beer, Jeremy M A; Freeman, David A

2012-12-01

Experiments measured the effects of laser glare on visual orientation and motion perception. Laser stimuli were varied according to spectral composition and temporal presentation as subjects identified targets' tilt (Experiment 1) and movement (Experiment 2). The objective was to determine whether the glare parameters would alter visual disruption. Three spectral profiles (monochromatic Green vs. polychromatic White vs. alternating Red-Green) were used to produce a ring of laser glare surrounding a target. Two experiments were performed to measure the minimum contrast required to report target orientation or motion direction. The temporal glare profile was also varied: the ring was illuminated either continuously or discontinuously. Time-averaged luminance of the glare stimuli was matched across all conditions. In both experiments, threshold (deltaL) values were approximately 0.15 log units higher in monochromatic Green than in polychromatic White conditions. In Experiment 2 (motion identification), thresholds were approximately 0.17 log units higher in rapidly flashing (6, 10, or 14 Hz) than in continuous exposure conditions. Monochromatic extended-source laser glare disrupted orientation and motion identification more than polychromatic glare. In the motion task, pulse trains faster than 6 Hz (but below flicker fusion) elevated thresholds more than continuous glare with the same time-averaged luminance. Under these conditions, alternating the wavelength of monochromatic glare over time did not aggravate disability relative to green-only glare. Repetitively flashing monochromatic laser glare induced occasional episodes of impaired motion identification, perhaps resulting from cognitive interference. Interference speckle might play a role in aggravating monochromatic glare effects.

Infrared fine-structure line diagnostics of shrouded active galactic nuclei

NASA Technical Reports Server (NTRS)

Voit, G. M.

1992-01-01

The ultraluminous far-IR galaxies revealed by IRAS, quasar-like in luminosity but smothered in molecular gas, probably conceal either immense starbursts or luminous active nuclei. In both scenarios, these objects ought to produce copious infrared fine-structure emission with several lines comparable to H-beta in luminosity. We show how these lines, if detected, can be used to determine the electron densities and far-IR obscurations of shrouded photoionized regions and to constrain the shape and ionization parameter of the ionizing spectra. The presence of Ne v emission in particular will distinguish shrouded AGNs from shrouded starbursts. Since all active galaxies photoionize at least some surrounding material, these diagnostics can also be applied to active galaxies in general and will aid in studying how an active nucleus interacts with the interstellar medium of its host galaxy.

Biologically inspired computation and learning in Sensorimotor Systems

NASA Astrophysics Data System (ADS)

Lee, Daniel D.; Seung, H. S.

2001-11-01

Networking systems presently lack the ability to intelligently process the rich multimedia content of the data traffic they carry. Endowing artificial systems with the ability to adapt to changing conditions requires algorithms that can rapidly learn from examples. We demonstrate the application of such learning algorithms on an inexpensive quadruped robot constructed to perform simple sensorimotor tasks. The robot learns to track a particular object by discovering the salient visual and auditory cues unique to that object. The system uses a convolutional neural network that automatically combines color, luminance, motion, and auditory information. The weights of the networks are adjusted using feedback from a teacher to reflect the reliability of the various input channels in the surrounding environment. Additionally, the robot is able to compensate for its own motion by adapting the parameters of a vestibular ocular reflex system.

Modulation of Cardiac Ryanodine Receptor Channels by Alkaline Earth Cations

PubMed Central

Diaz-Sylvester, Paula L.; Porta, Maura; Copello, Julio A.

2011-01-01

Cardiac ryanodine receptor (RyR2) function is modulated by Ca2+ and Mg2+. To better characterize Ca2+ and Mg2+ binding sites involved in RyR2 regulation, the effects of cytosolic and luminal earth alkaline divalent cations (M2+: Mg2+, Ca2+, Sr2+, Ba2+) were studied on RyR2 from pig ventricle reconstituted in bilayers. RyR2 were activated by M2+ binding to high affinity activating sites at the cytosolic channel surface, specific for Ca2+ or Sr2+. This activation was interfered by Mg2+ and Ba2+ acting at low affinity M2+-unspecific binding sites. When testing the effects of luminal M2+ as current carriers, all M2+ increased maximal RyR2 open probability (compared to Cs+), suggesting the existence of low affinity activating M2+-unspecific sites at the luminal surface. Responses to M2+ vary from channel to channel (heterogeneity). However, with luminal Ba2+or Mg2+, RyR2 were less sensitive to cytosolic Ca2+ and caffeine-mediated activation, openings were shorter and voltage-dependence was more marked (compared to RyR2 with luminal Ca2+or Sr2+). Kinetics of RyR2 with mixtures of luminal Ba2+/Ca2+ and additive action of luminal plus cytosolic Ba2+ or Mg2+ suggest luminal M2+ differentially act on luminal sites rather than accessing cytosolic sites through the pore. This suggests the presence of additional luminal activating Ca2+/Sr2+-specific sites, which stabilize high Po mode (less voltage-dependent) and increase RyR2 sensitivity to cytosolic Ca2+ activation. In summary, RyR2 luminal and cytosolic surfaces have at least two sets of M2+ binding sites (specific for Ca2+ and unspecific for Ca2+/Mg2+) that dynamically modulate channel activity and gating status, depending on SR voltage. PMID:22039534

Visual Perceptual Echo Reflects Learning of Regularities in Rapid Luminance Sequences.

PubMed

Chang, Acer Y-C; Schwartzman, David J; VanRullen, Rufin; Kanai, Ryota; Seth, Anil K

2017-08-30

A novel neural signature of active visual processing has recently been described in the form of the "perceptual echo", in which the cross-correlation between a sequence of randomly fluctuating luminance values and occipital electrophysiological signals exhibits a long-lasting periodic (∼100 ms cycle) reverberation of the input stimulus (VanRullen and Macdonald, 2012). As yet, however, the mechanisms underlying the perceptual echo and its function remain unknown. Reasoning that natural visual signals often contain temporally predictable, though nonperiodic features, we hypothesized that the perceptual echo may reflect a periodic process associated with regularity learning. To test this hypothesis, we presented subjects with successive repetitions of a rapid nonperiodic luminance sequence, and examined the effects on the perceptual echo, finding that echo amplitude linearly increased with the number of presentations of a given luminance sequence. These data suggest that the perceptual echo reflects a neural signature of regularity learning.Furthermore, when a set of repeated sequences was followed by a sequence with inverted luminance polarities, the echo amplitude decreased to the same level evoked by a novel stimulus sequence. Crucially, when the original stimulus sequence was re-presented, the echo amplitude returned to a level consistent with the number of presentations of this sequence, indicating that the visual system retained sequence-specific information, for many seconds, even in the presence of intervening visual input. Altogether, our results reveal a previously undiscovered regularity learning mechanism within the human visual system, reflected by the perceptual echo. SIGNIFICANCE STATEMENT How the brain encodes and learns fast-changing but nonperiodic visual input remains unknown, even though such visual input characterizes natural scenes. We investigated whether the phenomenon of "perceptual echo" might index such learning. The perceptual echo is a long-lasting reverberation between a rapidly changing visual input and evoked neural activity, apparent in cross-correlations between occipital EEG and stimulus sequences, peaking in the alpha (∼10 Hz) range. We indeed found that perceptual echo is enhanced by repeatedly presenting the same visual sequence, indicating that the human visual system can rapidly and automatically learn regularities embedded within fast-changing dynamic sequences. These results point to a previously undiscovered regularity learning mechanism, operating at a rate defined by the alpha frequency. Copyright © 2017 the authors 0270-6474/17/378486-12$15.00/0.

The effect of chromatic and luminance information on reaction times.

PubMed

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

2010-07-01

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

Luminal angiotensin II stimulates rat medullary thick ascending limb chloride transport in the presence of basolateral norepinephrine.

PubMed

Baum, Michel

2016-02-15

Angiotensin II (ANG II) is secreted by the proximal tubule resulting in a luminal concentration that is 100- to 1,000-fold greater than that in the blood. Luminal ANG II has been shown to stimulate sodium transport in the proximal tubule and distal nephron. Surprisingly, luminal ANG II inhibits NaCl transport in the medullary thick ascending limb (mTAL), a nephron segment responsible for a significant amount of NaCl absorption from the glomerular ultrafiltrate. We confirmed that addition of 10(-8) M ANG II to the lumen inhibited mTAL chloride transport (220 ± 19 to 165 ± 25 pmol·mm(-1)·min(-1), P < 0.01) and examined whether an interaction with basolateral norepinephrine existed to simulate the in vivo condition of an innervated tubule. We found that in the presence of a 10(-6) M norepinephrine bath, luminal ANG II stimulated mTAL chloride transport from 298 ± 18 to 364 ± 42 pmol·mm(-1)·min(-1) (P < 0.05). Stimulation of chloride transport by luminal ANG II was also observed with 10(-3) M bath dibutyryl cAMP in the bathing solution and bath isoproterenol. A bath of 10(-5) H-89 blocked the stimulation of chloride transport by norepinephrine and prevented the effect of luminal ANG II to either stimulate or inhibit chloride transport. Bath phentolamine, an α-adrenergic agonist, also prevented the decrease in mTAL chloride transport by luminal ANG II. Thus luminal ANG II increases chloride transport with basolateral norepinephrine; an effect likely mediated by stimulation of cAMP. Alpha-1 adrenergic stimulation prevents the inhibition of chloride transport by luminal ANG II. Copyright © 2016 the American Physiological Society.

76 FR 76625 - Association of State and Territorial Solid Waste Management Officials; Denial of Petition for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-08

... luminous exit signs do not require electricity or batteries, and are commonly installed in areas where... tritium exit signs are returned to the manufacturer for recycling or disposed of as low-level radioactive...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Short, M.T.; Osmand, A.P.

The acute phase of inflammation is characterized by numerous changes in blood composition, perhaps the most dramatic of these being the elevation of C-reactive protein levels. C-reactive protein (CRP) is known to bind to molecules containing phosphocholine-substituents following reaction with Ca/sup 2 +/ ions. Lumines

Minimum requirements for adequate nighttime conspicuity of highway signs

DOT National Transportation Integrated Search

1988-02-01

A laboratory and field study were conducted to assess the minimum luminance levels of signs to ensure that they will be detected and identified at adequate distances under nighttime driving conditions. A total of 30 subjects participated in the field...

Prototype mobile luminance measurement system and level of service for evaluating rural high-speed nighttime delineation.

DOT National Transportation Integrated Search

2013-02-01

Transportation agencies routinely travel their extensive roadway networks conducting subjective roadway : assessments of traffic control devices both day and night. Retroreflectivity is a good tool for product testing : but can provide false positive...

Spatial Standard Observer

NASA Technical Reports Server (NTRS)

Watson, Andrw B. (Inventor)

2010-01-01

The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image. or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image . Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer. SSO. Some embodiments include masking functions. window functions. special treatment for images lying on or near border and pre-processing of test images.

Spatial Standard Observer

NASA Technical Reports Server (NTRS)

Watson, Andrew B. (Inventor)

2012-01-01

The present invention relates to devices and methods for the measurement and/or for the specification of the perceptual intensity of a visual image, or the perceptual distance between a pair of images. Grayscale test and reference images are processed to produce test and reference luminance images. A luminance filter function is convolved with the reference luminance image to produce a local mean luminance reference image. Test and reference contrast images are produced from the local mean luminance reference image and the test and reference luminance images respectively, followed by application of a contrast sensitivity filter. The resulting images are combined according to mathematical prescriptions to produce a Just Noticeable Difference, JND value, indicative of a Spatial Standard Observer, SSO. Some embodiments include masking functions, window functions, special treatment for images lying on or near borders and pre-processing of test images.

Distinct Effects of Adipose-Derived Stem Cells and Adipocytes on Normal and Cancer Cell Hierarchy.

PubMed

Anjanappa, Manjushree; Burnett, Riesa; Zieger, Michael A; Merfeld-Clauss, Stephanie; Wooden, William; March, Keith; Tholpady, Sunil; Nakshatri, Harikrishna

2016-07-01

Adipose-derived stem cells (ASC) have received considerable attention in oncology because of the known direct link between obesity and cancer as well as the use of ASCs in reconstructive surgery after tumor ablation. Previous studies have documented how cancer cells commandeer ASCs to support their survival by altering extracellular matrix composition and stiffness, migration, and metastasis. This study focused on delineating the effects of ASCs and adipocytes on the self-renewal of stem/progenitor cells and hierarchy of breast epithelial cells. The immortalized breast epithelial cell line MCF10A, ductal carcinoma in situ (DCIS) cell lines MCF10DCIS.com and SUM225, and MCF10A-overexpressing SRC oncogene were examined using a mammosphere assay and flow cytometry for the effects of ASCs on their self-renewal and stem-luminal progenitor-differentiated cell surface marker profiles. Interestingly, ASCs promoted the self-renewal of all cell types except SUM225. ASC coculture or treatment with ASC conditioned media altered the number of CD49f(high)/EpCAM(low) basal/stem-like and CD49f(medium)/EpCAM(medium) luminal progenitor cells. Among multiple factors secreted by ASCs, IFNγ and hepatocyte growth factor (HGF) displayed unique actions on epithelial cell hierarchy. IFNγ increased stem/progenitor-like cells while simultaneously reducing the size of mammospheres, whereas HGF increased the size of mammospheres with an accompanying increase in luminal progenitor cells. ASCs expressed higher levels of HGF, whereas adipocytes expressed higher levels of IFNγ. As luminal progenitor cells are believed to be prone for transformation, IFNγ and HGF expression status of ASCs may influence susceptibility for developing breast cancer as well as on outcomes of autologous fat transplantation on residual/dormant tumor cells. This study suggests that the ratio of ASCs to adipocytes influences cancer cell hierarchy, which may impact incidence and progression. Mol Cancer Res; 14(7); 660-71. ©2016 AACR. ©2016 American Association for Cancer Research.

Cyclo-oxygenase isozymes in mucosal ulcergenic and functional responses following barrier disruption in rat stomachs.

PubMed

Hirata, T; Ukawa, H; Yamakuni, H; Kato, S; Takeuchi, K

1997-10-01

1. We examined the effects of selective and nonselective cyclo-oxygenase (COX) inhibitors on various functional changes in the rat stomach induced by topical application of taurocholate (TC) and investigated the preferential role of COX isozymes in these responses. 2. Rat stomachs mounted in ex vivo chambers were perfused with 50 mM HCl and transmucosal potential difference (p.d.), mucosal blood flow (GMBF), luminal acid loss and luminal levels of prostaglandin E2 (PGE2) were measured before, during and after exposure to 20 mM TC. 3. Mucosal application of TC in control rats caused a reduction in p.d., followed by an increase of luminal acid loss and GMBF, and produced only minimal damage in the mucosa 2 h later. Pretreatment with indomethacin (10 mg kg[-1], s.c.), a nonselective COX-1 and COX-2 inhibitor, attenuated the gastric hyperaemic response caused by TC without affecting p.d. and acid loss, resulting in haemorrhagic lesions in the mucosa. In contrast, selective COX-2 inhibitors, such as NS-398 and nimesulide (10 mg kg[-1], s.c.), had no effect on any of the responses induced by TC and did not cause gross damage in the mucosa. 4. Luminal PGE2 levels were markedly increased during and after exposure to TC and this response was significantly inhibited by indomethacin but not by either NS-398 or nimesulide. The expression of COX-1-mRNA was consistently detected in the gastric mucosa before and after TC treatment, while a faint expression of COX-2-mRNA was detected only 2 h after TC treatment. 5. Both NS-398 and nimesulide significantly suppressed carrageenan-induced rat paw oedema, similar to indomethacin. 6. These results confirmed a mediator role for prostaglandins in the gastric hyperaemic response following TC-induced barrier disruption, and suggest that COX-1 but not COX-2 is a key enzyme in maintaining 'housekeeping' functions in the gastric mucosa under both normal and adverse conditions.

The role of luminal Ca2+ in the generation of Ca2+ waves in rat ventricular myocytes

PubMed Central

Lukyanenko, Valeriy; Subramanian, Saisunder; Györke, Inna; Wiesner, Theodore F; Györke, Sandor

1999-01-01

We used confocal Ca2+ imaging and fluo-3 to investigate the transition of localized Ca2+ releases induced by focal caffeine stimulation into propagating Ca2+ waves in isolated rat ventricular myocytes. Self-sustaining Ca2+ waves could be initiated when the cellular Ca2+ load was increased by elevating the extracellular [Ca2+] ([Ca2+]o) and they could also be initiated at normal Ca2+ loads when the sensitivity of the release sites to cytosolic Ca2+ was enhanced by low doses of caffeine. When we prevented the accumulation of extra Ca2+ in the luminal compartment of the sarcoplasmic reticulum (SR) with thapsigargin, focal caffeine pulses failed to trigger self-sustaining Ca2+ waves on elevation of [Ca2+]o. Inhibition of SR Ca2+ uptake by thapsigargin in cells already preloaded with Ca2+ above normal levels did not prevent local Ca2+ elevations from triggering propagating waves. Moreover, wave velocity increased by 20 %. Tetracaine (0·75 mM) caused transient complete inhibition of both local and propagating Ca2+ signals, followed by full recovery of the responses due to increased SR Ca2+ accumulation. Computer simulations using a numerical model with spatially distinct Ca2+ release sites suggested that increased amounts of releasable Ca2+ might not be sufficient to generate self-sustaining Ca2+ waves under conditions of Ca2+ overload unless the threshold of release site Ca2+ activation was set at relatively low levels (< 1·5 μM). We conclude that the potentiation of SR Ca2+ release channels by luminal Ca2+ is an important factor in Ca2+ wave generation. Wave propagation does not require the translocation of Ca2+ from the spreading wave front into the SR. Instead, it relies on luminal Ca2+ sensitizing Ca2+ release channels to cytosolic Ca2+. PMID:10373699

The long goodbye

NASA Image and Video Library

2015-07-27

A dying star’s final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star’s demise is still quite lengthy by our standards, lasting tens of thousands of years! The star’s agony has culminated in a wonderful planetary nebula known as NGC 6565, a cloud of gas that was ejected from the star after strong stellar winds pushed the star’s outer layers away into space. Once enough material was ejected, the star’s luminous core was exposed and it began to produce ultraviolet radiation, exciting the surrounding gas to varying degrees and causing it to radiate in an attractive array of colours. These same colours can be seen in the famous and impressive Ring Nebula (heic1310), a prominent example of a nebula like this one. Planetary nebulae are illuminated for around 10 000 years before the central star begins to cool and shrink to become a white dwarf. When this happens, the star’s light drastically diminishes and ceases to excite the surrounding gas, so the nebula fades from view. A version of this image was entered into the Hubble’s Hidden Treasures basic image competition by contestant Matej Novak.

Mixing of Chromatic and Luminance Retinal Signals in Primate Area V1

PubMed Central

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

2015-01-01

Vision emerges from activation of chromatic and achromatic retinal channels whose interaction in visual cortex is still poorly understood. To investigate this interaction, we recorded neuronal activity from retinal ganglion cells and V1 cortical cells in macaques and measured their visual responses to grating stimuli that had either luminance contrast (luminance grating), chromatic contrast (chromatic grating), or a combination of the two (compound grating). As with parvocellular or koniocellular retinal ganglion cells, some V1 cells responded mostly to the chromatic contrast of the compound grating. As with magnocellular retinal ganglion cells, other V1 cells responded mostly to the luminance contrast and generated a frequency-doubled response to equiluminant chromatic gratings. Unlike magnocellular and parvocellular retinal ganglion cells, V1 cells formed a unimodal distribution for luminance/color preference with a 2- to 4-fold bias toward luminance. V1 cells associated with positive local field potentials in deep layers showed the strongest combined responses to color and luminance and, as a population, V1 cells encoded a diverse combination of luminance/color edges that matched edge distributions of natural scenes. Taken together, these results suggest that the primary visual cortex combines magnocellular and parvocellular retinal inputs to increase cortical receptive field diversity and to optimize visual processing of our natural environment. PMID:24464943

Research on effects of baffle position in an integrating sphere on the luminous flux measurement

NASA Astrophysics Data System (ADS)

Lin, Fangsheng; Li, Tiecheng; Yin, Dejin; Lai, Lei; Xia, Ming

2016-09-01

In the field of optical metrology, luminous flux is an important index to characterize the quality of electric light source. Currently, the majority of luminous flux measurement is based on the integrating sphere method, so measurement accuracy of integrating sphere is the key factor. There are plenty of factors affecting the measurement accuracy, such as coating, power and the position of light source. However, the baffle which is a key part of integrating sphere has important effects on the measurement results. The paper analyzes in detail the principle of an ideal integrating sphere. We use moving rail to change the relative position of baffle and light source inside the sphere. By experiments, measured luminous flux values at different distances between the light source and baffle are obtained, which we used to take analysis of the effects of different baffle position on the measurement. By theoretical calculation, computer simulation and experiment, we obtain the optimum position of baffle for luminous flux measurements. Based on the whole luminous flux measurement error analysis, we develop the methods and apparatus to improve the luminous flux measurement accuracy and reliability. It makes our unifying and transferring work of the luminous flux more accurate in East China and provides effective protection for our traceability system.

Esophageal luminal stenosis is an independent prognostic factor in esophageal squamous cell carcinoma

PubMed Central

Yang, Yu-Shang; Hu, Wei-Peng; Ni, Peng-Zhi; Wang, Wen-Ping; Yuan, Yong; Chen, Long-Qi

2017-01-01

Background Predictive value of preoperative endoscopic characteristic of esophageal tumor has not been fully evaluated. The aim of this study is to investigate the impact of esophageal luminal stenosis on survival for patients with resectable esophageal squamous cell carcinoma (ESCC). Methods The clinicopathologic characteristics of 623 ESCC patients who underwent curative resection as the primary treatment between January 2005 and April 2009 were retrospectively reviewed. The esophageal luminal stenosis measured by endoscopy was defined as a uniform measurement preoperatively. The impact of esophageal luminal stenosis on patients’ overall survival (OS) and relation with other clinicopathological features were assessed. A Cox regression model was used to identify prognostic factors. Results The results showed that OS significantly decreased in patients with manifest stenotic tumor compared with patients without luminal obstruction (P<0.05). Considerable esophageal luminal stenosis was associated with a higher T stage, longer tumor length, and poorer differentiation (all P<0.05). In multivariate survival analysis, esophageal luminal stenosis remained as an independent prognostic factor for OS (P= 0.036). Conclusions Esophageal luminal stenosis could have a significant impact on the OS in patients with resected ESCC and may provide additional prognostic value to the current staging system before any cancer-specific treatment. PMID:28118615

Luminal and systemic signals trigger intestinal adaptation in the juvenile python.

PubMed

Secor, S M; Whang, E E; Lane, J S; Ashley, S W; Diamond, J

2000-12-01

Juvenile pythons undergo large rapid upregulation of intestinal mass and intestinal transporter activities upon feeding. Because it is also easy to do surgery on pythons and to maintain them in the laboratory, we used a python model to examine signals and agents for intestinal adaptation. We surgically isolated the middle third of the small intestine from enteric continuity, leaving its mesenteric nerve and vascular supply intact. Intestinal continuity was restored by an end-to-end anastomosis between the proximal and distal thirds. Within 24 h of the snake's feeding, the reanastomosed proximal and distal segments (receiving luminal nutrients) had upregulated amino acid and glucose uptakes by up to 15-fold, had doubled intestinal mass, and thereby soon achieved total nutrient uptake capacities equal to those of the normal fed full-length intestine. At this time, however, the isolated middle segment, receiving no luminal nutrients, experienced no changes from the fasted state in either nutrient uptakes or in morphology. By 3 days postfeeding, the isolated middle segment had upregulated nutrient uptakes to the same levels as the reanastomosed proximal and distal segments, but it still lacked any appreciable morphological response. These contrasting results for the reanastomosed intestine and for the isolated middle segment suggest that luminal nutrients and/or pancreatic biliary secretions are the agents triggering rapid upregulation of transporters and of intestinal mass and that systemic nerve or hormonal signals later trigger transporter regulation but no trophic response.

A quantitative analysis of electrolyte exchange in the salivary duct

PubMed Central

Catalán, Marcelo A.; Melvin, James E.; Yule, David I.; Crampin, Edmund J.; Sneyd, James

2012-01-01

A healthy salivary gland secretes saliva in two stages. First, acinar cells generate primary saliva, a plasma-like, isotonic fluid high in Na+ and Cl−. In the second stage, the ducts exchange Na+ and Cl− for K+ and HCO3−, producing a hypotonic final saliva with no apparent loss in volume. We have developed a tool that aims to understand how the ducts achieve this electrolyte exchange while maintaining the same volume. This tool is part of a larger multiscale model of the salivary gland and can be used at the duct or gland level to investigate the effects of genetic and chemical alterations. In this study, we construct a radially symmetric mathematical model of the mouse salivary gland duct, representing the lumen, the cell, and the interstitium. For a given flow and primary saliva composition, we predict the potential differences and the luminal and cytosolic concentrations along a duct. Our model accounts well for experimental data obtained in wild-type animals as well as knockouts and chemical inhibitors. Additionally, the luminal membrane potential of the duct cells is predicted to be very depolarized compared with acinar cells. We investigate the effects of an electrogenic vs. electroneutral anion exchanger in the luminal membrane on concentration and the potential difference across the luminal membrane as well as how impairing the cystic fibrosis transmembrane conductance regulator channel affects other ion transporting mechanisms. Our model suggests the electrogenicity of the anion exchanger has little effect in the submandibular duct. PMID:22899825

Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal-Like, Luminal A, and Luminal B Breast Cancers

DTIC Science & Technology

2017-10-01

study to identify how various breast cancer risk factors differ in their relationships to different molecular subtypes of breast cancer and to further...characterize molecular differences between these subtypes. To address the existing research gaps regarding the etiologies of different molecular ... molecular subtypes of breast cancer, basal-like, luminal A, and luminal B tumors, breast cancer risk factors 16. SECURITY CLASSIFICATION OF: 17

Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal-Like, Luminal A, and Luminal B Breast Cancers

DTIC Science & Technology

2017-10-01

various breast cancer risk factors differ in their relationships to different molecular subtypes of breast cancer and to further characterize... molecular differences between these subtypes. To address the existing research gaps regarding the etiologies of different molecular subtypes of breast... molecular subtypes of breast cancer, basal-like, luminal A, and luminal B tumors, breast cancer risk factors 16. SECURITY CLASSIFICATION OF: 17. LIMITATION

Trilateral Intercomparison of Photometric Units Maintained at NIST (USA), NPL (UK), and PTB (Germany)

PubMed Central

Ohno, Yoshi; Goodman, Teresa; Sauter, Georg

1999-01-01

A trilateral intercomparison of photometric units between NIST (USA), NPL (UK), and PTB (Germany) has been conducted to update the knowledge of the relationship between the photometric units disseminated in the three countries. The luminous intensity unit (cd), the luminous responsivity scale (A/lx), and the luminous flux unit (lm) maintained at each laboratory were compared by circulating transfer standard lamps and photometers. The results showed that the relative luminous intensity values, with respect to the average, measured by NIST, NPL, and PTB were 1.0014, 1.0021, and 0.9966; the relative inverse values of the luminous responsivity (corresponding to illuminance) were 1.0023, 1.0011, and 0.9965; the relative luminous flux values were 0.9994, 1.0034, and 0.9972, respectively. The results agreed within the stated uncertainties of the units maintained at the three laboratories.

Progress of OLED devices with high efficiency at high luminance

NASA Astrophysics Data System (ADS)

Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

2014-03-01

Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

Flux of Kilogram-Sized Meteoroids from Lunar Impact Monitoring

NASA Technical Reports Server (NTRS)

Suggs, Robert; Suggs, Ron; Cooke, William; McNamara, Heather; Diekmann, Anne; Moser, Danielle; Swift, Wesley

2008-01-01

Routine lunar impact monitoring has harvested over 110 impacts in 2 years of observations using 0.25, 0.36 and 0.5 m telescopes and low-light-level video cameras. The night side of the lunar surface provides a large collecting area for detecting these impacts and allows estimation of the flux of meteoroids down to a limiting luminous energy. In order to determine the limiting mass for these observations, models of the sporadic meteoroid environment were used to determine the velocity distribution and new measurements of luminous efficiency were made at the Ames Vertical Gun Range. The flux of meteoroids in this size range has implications for Near Earth Object populations as well as for estimating impact ejecta risk for future lunar missions.

Role of epigenetic modifications in luminal breast cancer

PubMed Central

Abdel-Hafiz, Hany A; Horwitz, Kathryn B

2015-01-01

Luminal breast cancers represent approximately 75% of cases. Explanations into the causes of endocrine resistance are complex and are generally ascribed to genomic mechanisms. Recently, attention has been drawn to the role of epigenetic modifications in hormone resistance. We review these here. Epigenetic modifications are reversible, heritable and include changes in DNA methylation patterns, modification of histones and altered microRNA expression levels that target the receptors or their signaling pathways. Large-scale analyses indicate distinct epigenomic profiles that distinguish breast cancers from normal and benign tissues. Taking advantage of the reversibility of epigenetic modifications, drugs that target epigenetic modifiers, given in combination with chemotherapies or endocrine therapies, may represent promising approaches to restoration of therapy responsiveness in these cases. PMID:25689414

Increased Prevalence of Luminal Narrowing and Stricturing Identified by Enterography in Pediatric Crohn Disease Patients with Elevated Granulocyte-Macrophage Colony Stimulating Factor Auto-antibodies

PubMed Central

Dykes, Dana M.H.; Towbin, Alexander J.; Bonkowski, Erin; Chalk, Claudia; Bezold, Ramona; Lake, Kathleen; Kim, Mi-Ok; Heubi, James E.; Trapnell, Bruce C.; Podberesky, Daniel J.; Denson, Lee A.

2013-01-01

Background Crohn disease (CD) patients with elevated Granulocyte-Macrophage Colony-Stimulating Factor auto-antibodies (GM-CSF Ab) are more likely to develop stricturing behavior requiring surgery. Computed Tomography or Magnetic Resonance Enterography (CTE or MRE) may detect luminal narrowing (LN) prior to stricture development. Objective To determine whether CD patients with elevated GM-CSF Ab (≥ 1.6 mcg/mL) have a higher prevalence of LN and stricturing on CTE or MRE. Methods A single center, cross-sectional study of 153 pediatric CD patients and controls undergoing CTE or MRE. A novel scoring system evaluated for disease activity, presence of LN, stricture, intra-abdominal abscess, or fistulae Ouutcomes were compared with respect to antibody status using Fisher's exact test, logistic regression, and the unpaired t-test. Results GM-CSF Ab were elevated in CD patients (n=114) with a median (IQR) GM-CSF Ab level of 2.3 mcg/mL (0.5, 6.6) compared with healthy and disease controls, p=0.001. Ileal disease location was more common in CD patients with high GM-CSF Ab, p<0.001. Luminal narrowing increased from 39% in CD patients with low GM-CSF Ab to 71% in those with high levels (p=0.004). High GM-CSF Ab remained significantly associated with LN in a multivariate logistic model. Stricturing increased from 4% in CD patients with low GM-CSF Ab to 19% in those with high GM-CSF Ab (p=0.03). Conclusions Pediatric CD patients with high GM-CSF Ab levels have a higher prevalence of LN on CTE or MRE. Further study will be needed to determine whether medical therapy will reduce progression to stricturing behavior in these patients. PMID:23893081

Ionised outflows in z ~ 2.4 quasar host galaxies

NASA Astrophysics Data System (ADS)

Carniani, S.; Marconi, A.; Maiolino, R.; Balmaverde, B.; Brusa, M.; Cano-Díaz, M.; Cicone, C.; Comastri, A.; Cresci, G.; Fiore, F.; Feruglio, C.; La Franca, F.; Mainieri, V.; Mannucci, F.; Nagao, T.; Netzer, H.; Piconcelli, E.; Risaliti, G.; Schneider, R.; Shemmer, O.

2015-08-01

Aims: Outflows driven by active galactic nuclei (AGN) are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super-massive black holes and their host galaxies. We here aim to detect extended ionised outflows in luminous quasars, where we expect the highest activity both in star formation and in black-hole accretion. Currently, there are only a few studies based on spatially resolved observations of outflows at high redshift, z > 2. Methods: We analysed a sample of six luminous (L > 1047 erg/s) quasars at z ~ 2.4, observed in H-band using the near-IR integral field spectrometer SINFONI at the VLT. We performed a kinematic analysis of the [Oiii] emission line at λ = 5007 Å. Results: We detect fast, spatially extended outflows in five out of six targets. [Oiii]λ5007 has a complex gas kinematic, with blue-shifted velocities of a few hundreds of km s-1 and line widths up to 1500 km s-1. Using the spectroastrometric method, we infer a size of the ionised outflows of up to ~2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate, and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows that are driven by radiation pressure, which depends on the emitted luminosity. Conclusions: We derive mass outflow rates of about 6-700 M⊙ yr-1 for our sample, which are lower than those observed in molecular outflows. The physical properties of ionised outflows show dependences on AGN luminosity that are similar to those of molecular outflows, but indicate that the mass of ionised gas is lower than that of molecular outflows. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms. Based on Observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, P.ID: 086.B-0579(A).

Luminance uniformity compensation for OLED panels based on FPGA

NASA Astrophysics Data System (ADS)

Ou, Peng; Yang, Gang; Jiang, Quan; Yu, Jun-Sheng; Wu, Qi-Peng; Shang, Fu-Hai; Yin, Wei; Wang, Jun; Zhong, Jian; Luo, Kai-Jun

2009-09-01

Aiming at the problem of luminance uniformity for organic lighting-emitting diode (OLED) panels, a new brightness calculating method based on bilinear interpolation is proposed. The irradiance time of each pixel reaching the same luminance is figured out by Matlab. Adopting the 64×32-pixel, single color and passive matrix OLED panel as adjusting luminance uniformity panel, a new circuit compensating scheme based on FPGA is designed. VHDL is used to make each pixel’s irradiance time in one frame period written in program. The irradiance brightness is controlled by changing its irradiance time, and finally, luminance compensation of the panel is realized. The simulation result indicates that the design is reasonable.

Photometric observations of local rocket-atmosphere interactions

NASA Astrophysics Data System (ADS)

Greer, R. G. H.; Murtagh, D. P.; Witt, G.; Stegman, J.

1983-06-01

Photometric measurements from rocket flights which recorded a strong foreign luminance in the altitude region between 90 and 130 km are reported. From one Nike-Orion rocket the luminance appeared on both up-leg and down-leg; from a series of Petrel rockets the luminance was apparent only on the down-leg. The data suggest that the luminance may be distributed mainly in the wake region along the rocket trajectory. The luminance is believed to be due to a local interaction between the rocket and the atmosphere although the precise nature of the interaction is unknown. It was measured at wavelengths ranging from 275 nm to 1.61 microns and may be caused by a combination of reactions.

Second-order statistics of colour codes modulate transformations that effectuate varying degrees of scene invariance and illumination invariance.

PubMed

Mausfeld, Rainer; Andres, Johannes

2002-01-01

We argue, from an ethology-inspired perspective, that the internal concepts 'surface colours' and 'illumination colours' are part of the data format of two different representational primitives. Thus, the internal concept of 'colour' is not a unitary one but rather refers to two different types of 'data structure', each with its own proprietary types of parameters and relations. The relation of these representational structures is modulated by a class of parameterised transformations whose effects are mirrored in the idealised computational achievements of illumination invariance of colour codes, on the one hand, and scene invariance, on the other hand. Because the same characteristics of a light array reaching the eye can be physically produced in many different ways, the visual system, then, has to make an 'inference' whether a chromatic deviation of the space-averaged colour codes from the neutral point is due to a 'non-normal', ie chromatic, illumination or due to an imbalanced spectral reflectance composition. We provide evidence that the visual system uses second-order statistics of chromatic codes of a single view of a scene in order to modulate corresponding transformations. In our experiments we used centre surround configurations with inhomogeneous surrounds given by a random structure of overlapping circles, referred to as Seurat configurations. Each family of surrounds has a fixed space-average of colour codes, but differs with respect to the covariance matrix of colour codes of pixels that defines the chromatic variance along some chromatic axis and the covariance between luminance and chromatic channels. We found that dominant wavelengths of red-green equilibrium settings of the infield exhibited a stable and strong dependence on the chromatic variance of the surround. High variances resulted in a tendency towards 'scene invariance', low variances in a tendency towards 'illumination invariance' of the infield.

Metabolic profiles of triple-negative and luminal A breast cancer subtypes in African-American identify key metabolic differences.

PubMed

Tayyari, Fariba; Gowda, G A Nagana; Olopade, Olufunmilayo F; Berg, Richard; Yang, Howard H; Lee, Maxwell P; Ngwa, Wilfred F; Mittal, Suresh K; Raftery, Daniel; Mohammed, Sulma I

2018-02-20

Breast cancer, a heterogeneous disease with variable pathophysiology and biology, is classified into four major subtypes. While hormonal- and antibody-targeted therapies are effective in the patients with luminal and HER-2 subtypes, the patients with triple-negative breast cancer (TNBC) subtype do not benefit from these therapies. The incidence rates of TNBC subtype are higher in African-American women, and the evidence indicates that these women have worse prognosis compared to women of European descent. The reasons for this disparity remain unclear but are often attributed to TNBC biology. In this study, we performed metabolic analysis of breast tissues to identify how TNBC differs from luminal A breast cancer (LABC) subtypes within the African-American and Caucasian breast cancer patients, respectively. We used High-Resolution Magic Angle Spinning (HR-MAS) 1H Nuclear magnetic resonance (NMR) to perform the metabolomic analysis of breast cancer and adjacent normal tissues (total n=82 samples). TNBC and LABC subtypes in African American women exhibited different metabolic profiles. Metabolic profiles of these subtypes were also distinct from those revealed in Caucasian women. TNBC in African-American women expressed higher levels of glutathione, choline, and glutamine as well as profound metabolic alterations characterized by decreased mitochondrial respiration and increased glycolysis concomitant with decreased levels of ATP. TNBC in Caucasian women was associated with increased pyrimidine synthesis. These metabolic alterations could potentially be exploited as novel treatment targets for TNBC.

Metabolic profiles of triple-negative and luminal A breast cancer subtypes in African-American identify key metabolic differences

PubMed Central

Tayyari, Fariba; Gowda, G.A. Nagana; Olopade, Olufunmilayo F.; Berg, Richard; Yang, Howard H.; Lee, Maxwell P.; Ngwa, Wilfred F.; Mittal, Suresh K.; Raftery, Daniel; Mohammed, Sulma I.

2018-01-01

Breast cancer, a heterogeneous disease with variable pathophysiology and biology, is classified into four major subtypes. While hormonal- and antibody-targeted therapies are effective in the patients with luminal and HER-2 subtypes, the patients with triple-negative breast cancer (TNBC) subtype do not benefit from these therapies. The incidence rates of TNBC subtype are higher in African-American women, and the evidence indicates that these women have worse prognosis compared to women of European descent. The reasons for this disparity remain unclear but are often attributed to TNBC biology. In this study, we performed metabolic analysis of breast tissues to identify how TNBC differs from luminal A breast cancer (LABC) subtypes within the African-American and Caucasian breast cancer patients, respectively. We used High-Resolution Magic Angle Spinning (HR-MAS) 1H Nuclear magnetic resonance (NMR) to perform the metabolomic analysis of breast cancer and adjacent normal tissues (total n=82 samples). TNBC and LABC subtypes in African American women exhibited different metabolic profiles. Metabolic profiles of these subtypes were also distinct from those revealed in Caucasian women. TNBC in African-American women expressed higher levels of glutathione, choline, and glutamine as well as profound metabolic alterations characterized by decreased mitochondrial respiration and increased glycolysis concomitant with decreased levels of ATP. TNBC in Caucasian women was associated with increased pyrimidine synthesis. These metabolic alterations could potentially be exploited as novel treatment targets for TNBC. PMID:29545929

Pixel-Wise-Inter/Intra-Channel Color and Luminance Uniformity Corrections for Multi-Channel Projection Displays

DTIC Science & Technology

2016-08-11

Journal Article 3. DATES COVERED (From – To) Jan 2015 – Dec 2015 4. TITLE AND SUBTITLE PIXEL-WISE INTER/INTRA-CHANNEL COLOR & LUMINANCE UNIFORMITY...Conference Dayton, Ohio – 28-29 June 2016 14. ABSTRACT Inter- and intra-channel color and luminance are generally non-uniform in multi-channel...projection display systems. Several methods have been proposed to correct for both inter- and intra-channel color and luminance variation in multi-channel

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

PubMed

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

2015-07-01

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

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

PubMed Central

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

2012-01-01

Vernier thresholds are known to be elevated when a target pair has opposite contrast polarity. Polarity reversal is used to assess the role of luminance and chromatic pathways in hyperacuity performance. Psychophysical hyperacuity thresholds were measured for pairs of gratings of various combinations of luminance (Lum) and chromatic (Chr) contrast polarities, at different ratios of luminance to chromatic contrast. With two red-green gratings of matched luminance and chromatic polarity (+Lum+Chr), there was an elevation of threshold at isoluminance. When both luminance and chromatic polarity were mismatched (−Lum−Chr), thresholds were substantially elevated under all conditions. With the same luminance contrast polarity and opposite chromatic polarity (+Lum−Chr) thresholds were only elevated close to isoluminance; in the reverse condition (−Lum+Chr), thresholds were elevated as in the −Lum−Chr condition except close to equiluminance. Similar data were obtained for gratings isolating the short-wavelength cone mechanism. Further psychophysical measurements assessed the role of target separation with matched or mismatched contrast polarity; similar results were found for luminance and chromatic gratings. Comparison physiological data were collected from parafoveal ganglion cells of the macaque retina. Positional precision of ganglion cell signals was assessed under conditions related to the psychophysical measurements. On the basis of these combined observations, it is argued that both magnocellular, parvocellular, and koniocellular pathways have access to cortical positional mechanisms associated with vernier acuity. PMID:22306680

Fusion of visible and near-infrared images based on luminance estimation by weighted luminance algorithm

NASA Astrophysics Data System (ADS)

Wang, Zhun; Cheng, Feiyan; Shi, Junsheng; Huang, Xiaoqiao

2018-01-01

In a low-light scene, capturing color images needs to be at a high-gain setting or a long-exposure setting to avoid a visible flash. However, such these setting will lead to color images with serious noise or motion blur. Several methods have been proposed to improve a noise-color image through an invisible near infrared flash image. A novel method is that the luminance component and the chroma component of the improved color image are estimated from different image sources [1]. The luminance component is estimated mainly from the NIR image via a spectral estimation, and the chroma component is estimated from the noise-color image by denoising. However, it is challenging to estimate the luminance component. This novel method to estimate the luminance component needs to generate the learning data pairs, and the processes and algorithm are complex. It is difficult to achieve practical application. In order to reduce the complexity of the luminance estimation, an improved luminance estimation algorithm is presented in this paper, which is to weight the NIR image and the denoised-color image and the weighted coefficients are based on the mean value and standard deviation of both images. Experimental results show that the same fusion effect at aspect of color fidelity and texture quality is achieved, compared the proposed method with the novel method, however, the algorithm is more simple and practical.

Visual ergonomic evaluations on four different designs of LED traffic signs

NASA Astrophysics Data System (ADS)

Chen, Yi-Chun; Huang, Ting-Yuan; Lee, Tsung-Xian; Sun, Ching-Cherng

2017-08-01

To investigate the legibility and visual comfort of LED traffic signs, an ergonomic experiment is performed on four custom-designed LED traffic signs, including three self-luminous ones as LED lightbox, LED backlight and regional LED backlight, and one non-self-luminous sign with external LED lighting. The four signs are hanged side-by-side and evaluated by observers through questionnaires. The signage dimension is one-sixth of the real freeway traffic signs, and the observation distance is 25 m. The luminance of three self-luminous signs is 216 cd/m2. The illuminance of external LED lighting is 400 lux on the traffic sign. The ambient illuminance is 2.8 and 6.0 lux in two rounds. The results show that self-luminous traffic signs provide superior legibility, visual comfort and user preference than the non-self-luminous one. Among the three self-luminous signs, regional LED backlight is most susceptible to the ambient illumination. LED lightbox has significantly better preference score than LED backlight under darker ambient lighting. Only LED lightbox has significantly better visual comfort than external LED lighting in the brighter environment. Based on the four LED traffic signs evaluated in this study, we suggest LED lightbox as the prior choice. Further investigations on the effect of ambient illumination and other designs of self-luminous traffic signs are in progress.

Visual Categorization of Natural Movies by Rats

PubMed Central

Vinken, Kasper; Vermaercke, Ben

2014-01-01

Visual categorization of complex, natural stimuli has been studied for some time in human and nonhuman primates. Recent interest in the rodent as a model for visual perception, including higher-level functional specialization, leads to the question of how rodents would perform on a categorization task using natural stimuli. To answer this question, rats were trained in a two-alternative forced choice task to discriminate movies containing rats from movies containing other objects and from scrambled movies (ordinate-level categorization). Subsequently, transfer to novel, previously unseen stimuli was tested, followed by a series of control probes. The results show that the animals are capable of acquiring a decision rule by abstracting common features from natural movies to generalize categorization to new stimuli. Control probes demonstrate that they did not use single low-level features, such as motion energy or (local) luminance. Significant generalization was even present with stationary snapshots from untrained movies. The variability within and between training and test stimuli, the complexity of natural movies, and the control experiments and analyses all suggest that a more high-level rule based on more complex stimulus features than local luminance-based cues was used to classify the novel stimuli. In conclusion, natural stimuli can be used to probe ordinate-level categorization in rats. PMID:25100598

Frames as visual links between paintings and the museum environment: an analysis of statistical image properties

PubMed Central

Redies, Christoph; Groß, Franziska

2013-01-01

Frames provide a visual link between artworks and their surround. We asked how image properties change as an observer zooms out from viewing a painting alone, to viewing the painting with its frame and, finally, the framed painting in its museum environment (museum scene). To address this question, we determined three higher-order image properties that are based on histograms of oriented luminance gradients. First, complexity was measured as the sum of the strengths of all gradients in the image. Second, we determined the self-similarity of histograms of the orientated gradients at different levels of spatial analysis. Third, we analyzed how much gradient strength varied across orientations (anisotropy). Results were obtained for three art museums that exhibited paintings from three major periods of Western art. In all three museums, the mean complexity of the frames was higher than that of the paintings or the museum scenes. Frames thus provide a barrier of complexity between the paintings and their exterior. By contrast, self-similarity and anisotropy values of images of framed paintings were intermediate between the images of the paintings and the museum scenes, i.e., the frames provided a transition between the paintings and their surround. We also observed differences between the three museums that may reflect modified frame usage in different art periods. For example, frames in the museum for 20th century art tended to be smaller and less complex than in the two other two museums that exhibit paintings from earlier art periods (13th–18th century and 19th century, respectively). Finally, we found that the three properties did not depend on the type of reproduction of the paintings (photographs in museums, scans from books or images from the Google Art Project). To the best of our knowledge, this study is the first to investigate the relation between frames and paintings by measuring physically defined, higher-order image properties. PMID:24265625

The effect of time in use on the display performance of the iPad.

PubMed

Caffery, Liam J; Manthey, Kenneth L; Sim, Lawrence H

2016-07-01

The aim of this study was to evaluate changes to the luminance, luminance uniformity and conformance to the digital imaging and communication in medicine greyscale standard display function (GSDF) as a function of time in use for the iPad. Luminance measurements of the American Association of Physicists in Medicine (AAPM) Group 18 task group (TG18) luminance uniformity and luminance test patterns (TG18-UNL and TG18-LN8) were performed using a calibrated near-range luminance meter. Nine sets of measurements were taken, where the time in use of the iPad ranged from 0 to 2500 h. The maximum luminance (Lmax) of the display decreased (367-338 cdm(-2)) as a function of time. The minimum luminance remained constant. The maximum non-uniformity coefficient was 11%. Luminance uniformity decreased slightly as a function of time in use. The conformance of the iPad deviated from the GSDF curve at commencement of use. Deviation did not increase as a function of time in use. This study has demonstrated that the iPad display exhibits luminance degradation typical of liquid crystal displays. The Lmax of the iPad fell below the American College of Radiology-AAPM-Society of Imaging Informatics in Medicine recommendations for primary displays (>350 cdm(-2)) at approximately 1000 h in use. The Lmax recommendation for secondary displays (>250 cdm(-2)) was exceeded during the entire study. The maximum non-uniformity coefficient did not exceed the recommendations for either primary or secondary displays. The deviation from the GSDF exceeded the recommendations of the TG18 for use as either a primary or secondary display. The brightness, uniformity and contrast response are reasonably stable over the useful lifetime of the device; however, the device fails to meet the contrast response standard for either a primary or secondary display.

Interaction of color and geometric cues in depth perception: when does "red" mean "near"?

PubMed

Guibal, Christophe R C; Dresp, Birgitta

2004-12-01

Luminance and color are strong and self-sufficient cues to pictorial depth in visual scenes and images. The present study investigates the conditions under which luminance or color either strengthens or overrides geometric depth cues. We investigated how luminance contrast associated with the color red and color contrast interact with relative height in the visual field, partial occlusion, and interposition to determine the probability that a given figure presented in a pair is perceived as "nearer" than the other. Latencies of "near" responses were analyzed to test for effects of attentional selection. Figures in a pair were supported by luminance contrast (Experiment 1) or isoluminant color contrast (Experiment 2) and combined with one of the three geometric cues. The results of Experiment 1 show that the luminance contrast of a color (here red), when it does not interact with other colors, produces the same effects as achromatic luminance contrasts. The probability of "near" increases with the luminance contrast of the color stimulus, the latencies for "near" responses decrease with increasing luminance contrast. Partial occlusion is found to be a strong enough pictorial cue to support a weaker red luminance contrast. Interposition cues lose out against cues of spatial position and partial occlusion. The results of Experiment 2, with isoluminant displays of varying color contrast, reveal that red color contrast on a light background supported by any of the three geometric cues wins over green or white supported by any of the three geometric cues. On a dark background, red color contrast supported by the interposition cue loses out against green or white color contrast supported by partial occlusion. These findings reveal that color is not an independent depth cue, but is strongly influenced by luminance contrast and stimulus geometry. Systematically shorter response latencies for stronger "near" percepts demonstrate that selective visual attention reliably detects the most likely depth cue combination in a given configuration.

Optimal Solution Volume for Luminal Preservation: A Preclinical Study in Porcine Intestinal Preservation.

PubMed

Oltean, M; Papurica, M; Jiga, L; Hoinoiu, B; Glameanu, C; Bresler, A; Patrut, G; Grigorie, R; Ionac, M; Hellström, M

2016-03-01

Rodent studies suggest that luminal solutions alleviate the mucosal injury and prolong intestinal preservation but concerns exist that excessive volumes of luminal fluid may promote tissue edema. Differences in size, structure, and metabolism between rats and humans require studies in large animals before clinical use. Intestinal procurement was performed in 7 pigs. After perfusion with histidine-tryptophan-ketoglutarate (HTK), 40-cm-long segments were cut and filled with 13.5% polyethylene glycol (PEG) 3350 solution as follows: V0 (controls, none), V1 (0.5 mL/cm), V2 (1 mL/cm), V3 (1.5 mL/cm), and V4 (2 mL/cm). Tissue and luminal solutions were sampled after 8, 14, and 24 hours of cold storage (CS). Preservation injury (Chiu score), the apical membrane (ZO-1, brush-border maltase activity), and the electrolyte content in the luminal solution were studied. In control intestines, 8-hour CS in HTK solution resulted in minimal mucosal changes (grade 1) that progressed to significant subepithelial edema (grade 3) by 24 hours. During this time, a gradual loss in ZO-1 was recorded, whereas maltase activity remained unaltered. Moreover, variable degrees of submucosal edema were observed. Luminal introduction of high volumes (2 mL/mL) of PEG solution accelerated the development of the subepithelial edema and submucosal edema, leading to worse histology. However, ZO-1 was preserved better over time than in control intestines (no luminal solution). Maltase activity was reduced in intestines receiving luminal preservation. Luminal sodium content decreased in time and did not differ between groups. This PEG solution protects the apical membrane and the tight-junction proteins but may favor water absorption and tissue (submucosal) edema, and luminal volumes >2 mL/cm may result in worse intestinal morphology. Copyright © 2016 Elsevier Inc. All rights reserved.

High-efficiency white OLEDs based on small molecules

NASA Astrophysics Data System (ADS)

Hatwar, Tukaram K.; Spindler, Jeffrey P.; Ricks, M. L.; Young, Ralph H.; Hamada, Yuuhiko; Saito, N.; Mameno, Kazunobu; Nishikawa, Ryuji; Takahashi, Hisakazu; Rajeswaran, G.

2004-02-01

Eastman Kodak Company and SANYO Electric Co., Ltd. recently demonstrated a 15" full-color, organic light-emitting diode display (OLED) using a high-efficiency white emitter combined with a color-filter array. Although useful for display applications, white emission from organic structures is also under consideration for other applications, such as solid-state lighting, where high efficiency and good color rendition are important. By incorporating adjacent blue and orange emitting layers in a multi-layer structure, highly efficient, stable white emission has been attained. With suitable host and dopant combinations, a luminance yield of 20 cd/A and efficiency of 8 lm/W have been achieved at a drive voltage of less than 8 volts and luminance level of 1000 cd/m2. The estimated external efficiency of this device is 6.3% and a high level of operational stability is observed. To our knowledge, this is the highest performance reported so far for white organic electroluminescent devices. We will review white OLED technology and discuss the fabrication and operating characteristics of these devices.

Enhancing Three-dimensional Movement Control System for Assemblies of Machine-Building Facilities

NASA Astrophysics Data System (ADS)

Kuzyakov, O. N.; Andreeva, M. A.

2018-01-01

Aspects of enhancing three-dimensional movement control system are given in the paper. Such system is to be used while controlling assemblies of machine-building facilities, which is a relevant issue. The base of the system known is three-dimensional movement control device with optical principle of action. The device consists of multi point light emitter and light receiver matrix. The processing of signals is enhanced to increase accuracy of measurements by switching from discrete to analog signals. Light receiver matrix is divided into four areas, and the output value of each light emitter in each matrix area is proportional to its luminance level. Thus, determing output electric signal value of each light emitter in corresponding area leads to determing position of multipoint light emitter and position of object tracked. This is done by using Case-based reasoning method, the precedent in which is described as integral signal value of each matrix area, coordinates of light receivers, which luminance level is high, and decision to be made in this situation.

Determination of eye safety filter protection factors associated with retinal thermal hazard and blue light photochemical hazard for intense pulsed light sources.

PubMed

Clarkson, D McG

2006-02-21

An assessment is provided of protection factors afforded for retinal thermal hazard and blue light photochemical hazard for a range of filters used with intense pulsed light sources (IPLs). A characteristic IPL spectrum based on black body radiation at 5000 K with a low cut filter at 515 nm was identified as suitable for such estimations. Specific filters assessed included types with idealized transmission properties and also a range of types whose transmission characteristics were measured by means of a Bentham DMc150 spectroradiometer. Predicted behaviour based on these spectra is outlined which describes both the effectiveness of protection and the level of luminous transmittance afforded. The analysis showed it was possible to describe a figure of merit for a particular filter material relating the degree of protection provided and corresponding value of luminous transmittance. This consideration is important for providing users of IPL equipment with safety eyewear with adequate level of visual transmittance.

NOTE: Determination of eye safety filter protection factors associated with retinal thermal hazard and blue light photochemical hazard for intense pulsed light sources

NASA Astrophysics Data System (ADS)

McG Clarkson, D.

2006-02-01

An assessment is provided of protection factors afforded for retinal thermal hazard and blue light photochemical hazard for a range of filters used with intense pulsed light sources (IPLs). A characteristic IPL spectrum based on black body radiation at 5000 K with a low cut filter at 515 nm was identified as suitable for such estimations. Specific filters assessed included types with idealized transmission properties and also a range of types whose transmission characteristics were measured by means of a Bentham DMc150 spectroradiometer. Predicted behaviour based on these spectra is outlined which describes both the effectiveness of protection and the level of luminous transmittance afforded. The analysis showed it was possible to describe a figure of merit for a particular filter material relating the degree of protection provided and corresponding value of luminous transmittance. This consideration is important for providing users of IPL equipment with safety eyewear with adequate level of visual transmittance.

Atmosphere-based image classification through luminance and hue

NASA Astrophysics Data System (ADS)

Xu, Feng; Zhang, Yujin

2005-07-01

In this paper a novel image classification system is proposed. Atmosphere serves an important role in generating the scene"s topic or in conveying the message behind the scene"s story, which belongs to abstract attribute level in semantic levels. At first, five atmosphere semantic categories are defined according to rules of photo and film grammar, followed by global luminance and hue features. Then the hierarchical SVM classifiers are applied. In each classification stage, corresponding features are extracted and the trained linear SVM is implemented, resulting in two classes. After three stages of classification, five atmosphere categories are obtained. At last, the text annotation of the atmosphere semantics and the corresponding features by Extensible Markup Language (XML) in MPEG-7 is defined, which can be integrated into more multimedia applications (such as searching, indexing and accessing of multimedia content). The experiment is performed on Corel images and film frames. The classification results prove the effectiveness of the definition of atmosphere semantic classes and the corresponding features.

Vibrationally Excited HCN in the Luminous Infrared Galaxy NGC 4418

NASA Astrophysics Data System (ADS)

Sakamoto, Kazushi; Aalto, Susanne; Evans, Aaron S.; Wiedner, Martina C.; Wilner, David J.

2010-12-01

Infrared pumping and its effect on the excitation of HCN molecules can be important when using rotational lines of HCN to probe dense molecular gas in galaxy nuclei. We report the first extragalactic detection of (sub)millimeter rotational lines of vibrationally excited HCN, in the dust-enshrouded nucleus of the luminous infrared galaxy NGC 4418. We estimate the excitation temperature of Tvib ≈ 230 K between the vibrational ground and excited (v 2 = 1) states. This excitation is most likely due to infrared radiation. At this high vibrational temperature the path through the v 2 = 1 state must have a strong impact on the rotational excitation in the vibrational ground level, although it may not be dominant for all rotational levels. Our observations also revealed nearly confusion-limited lines of CO, HCN, HCO+, H13CN, HC15N, CS, N2H+, and HC3N at λ ~ 1 mm. Their relative intensities may also be affected by the infrared pumping.

Internal noise sources limiting contrast sensitivity.

PubMed

Silvestre, Daphné; Arleo, Angelo; Allard, Rémy

2018-02-07

Contrast sensitivity varies substantially as a function of spatial frequency and luminance intensity. The variation as a function of luminance intensity is well known and characterized by three laws that can be attributed to the impact of three internal noise sources: early spontaneous neural activity limiting contrast sensitivity at low luminance intensities (i.e. early noise responsible for the linear law), probabilistic photon absorption at intermediate luminance intensities (i.e. photon noise responsible for de Vries-Rose law) and late spontaneous neural activity at high luminance intensities (i.e. late noise responsible for Weber's law). The aim of this study was to characterize how the impact of these three internal noise sources vary with spatial frequency and determine which one is limiting contrast sensitivity as a function of luminance intensity and spatial frequency. To estimate the impact of the different internal noise sources, the current study used an external noise paradigm to factorize contrast sensitivity into equivalent input noise and calculation efficiency over a wide range of luminance intensities and spatial frequencies. The impact of early and late noise was found to drop linearly with spatial frequency, whereas the impact of photon noise rose with spatial frequency due to ocular factors.

Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal-Like, Luminal A, and Luminal B Breast Cancers

DTIC Science & Technology

2014-10-01

Under Dr. Li’s supervision, the study coordinator, Ms. Taylor, will oversee the training of the study’s field and random digit dialing (RDD...so that luminal A and luminal B cases can be distinguished from each other. All triple-negative cases will be evaluated for EGFR and cytokeratin 5/6...mutations and small indels will be validated by PCR amplification of the identified exons in tumor and matched normal DNA followed by PCR cleanup using

Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal-Like, Luminal A, and Luminal B Breast Cancers

DTIC Science & Technology

2013-10-01

will oversee the training of the study’s field and random digit dialing (RDD) interviewers. To support this and on-going training, Ms. Taylor will...luminal A and luminal B cases can be distinguished from each other. All Page 9 triple-negative cases will be evaluated for EGFR and cytokeratin 5/6...point mutations and small indels will be validated by PCR amplification of the identified exons in tumor and matched normal DNA followed by PCR

Method and apparatus for an optical function generator for seamless tiled displays

NASA Technical Reports Server (NTRS)

Johnson, Michael (Inventor); Chen, Chung-Jen (Inventor)

2004-01-01

Producing seamless tiled images from multiple displays includes measuring a luminance profile of each of the displays, computing a desired luminance profile for each of the displays, and determining a spatial gradient profile of each of the displays based on the measured luminance profile and the computed desired luminance profile. The determined spatial gradient profile is applied to a spatial filter to be inserted into each of the displays to produce the seamless tiled display image.

Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal Like, Luminal A, and Luminal B Breast Cancers

DTIC Science & Technology

2016-10-01

like, luminal A, and luminal B tumors. Our original goal was to recruit about 2,700 women in Western Washington who have been diagnosed with breast...cancer to compare to 900 women who have never been diagnosed with breast cancer, but control ascertainment has been unacceptably low, so on 8/25/15 we...group of 900 women without breast cancer. Control ascertainment did not go as planned due to significant changes in telephone equipment and practices

Peripheral visual response time and retinal luminance-area relations

NASA Technical Reports Server (NTRS)

Haines, R. F.

1975-01-01

Experiments were undertaken to elucidate the stimulus luminance-retinal area relationship that underlies response time (RT) behavior. Mean RT was significantly faster to stimuli imaged beyond about 70 deg of arc from the fovea when their luminance was increased by an amount equal to the foveal stimulus luminance multiplied by the cosine of the angle between the peripheral stimuli and the line of sight. This and additional data are discussed in relation to previous psychophysical data and to possible response mechanisms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGreer, Ian D.; Fan Xiaohui; Bian Fuyan

We report the discovery of a gravitationally lensed quasar identified serendipitously in the Sloan Digital Sky Survey (SDSS). The object, SDSS J094604.90+183541.8, was initially targeted for spectroscopy as a luminous red galaxy, but the SDSS spectrum has the features of both a z = 0.388 galaxy and a z = 4.8 quasar. We have obtained additional imaging that resolves the system into two quasar images separated by 3.''06 and a bright galaxy that is strongly blended with one of the quasar images. We confirm spectroscopically that the two quasar images represent a single-lensed source at z = 4.8 with amore » total magnification of 3.2, and we derive a model for the lensing galaxy. This is the highest redshift lensed quasar currently known. We examine the issues surrounding the selection of such an unusual object from existing data and briefly discuss implications for lensed quasar surveys.« less

The galactic luminous supersoft X-ray source RXJ0925.7-4758 / MR Vel

NASA Astrophysics Data System (ADS)

Prodhani, Nandita; Baruah, Monmoyuri

2018-02-01

A steady-state model has been considered to explain the observed properties of the LSSS RXJ0925.7-4748 / MR Vel. The steady-state models consist of a C-O core surrounded by a hydrogen-rich envelope of the solar abundances. At the bottom of the envelope, hydrogen is burned at the same rate as the star accreted it. Using the most recent proton capturing reaction rates and β -decay rates, the cyclic reactions have been studied. In the present work, effort has been made to explain the observed characteristics of the source RXJ0925.7-4758 / MR Vel considering the above mentioned model. The calculated values of luminosity (8.56 × 10^{37} erg s^{-1}) and effective temperature (94.19 eV) tally well with the observed one. Photoionisation code CLOUDY has been used to explain the observed absorption edges in the spectrum of RXJ0925.7-4758 / MR Vel.

Preliminary study on detection sediment contamination in soil affected by the Indian Ocean giant tsunami 2004 in Aceh, Indonesia using laser-induced breakdown spectroscopy (LIBS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Idris, Nasrullah, E-mail: nasrullah.idris@unsyiah.ac.id; Ramli, Muliadi; Hedwig, Rinda

This work is intended to asses the capability of LIBS for the detection of the tsunami sediment contamination in soil. LIBS apparatus used in this work consist of a laser system and an optical multichannel analyzer (OMA) system. The soil sample was collected from in Banda Aceh City, Aceh, Indonesia, the most affected region by the giant Indian Ocean tsunami 2004. The laser beam was focused onto surface of the soil pellet using a focusing lens to produce luminous plasma. The experiment was conducted under air as surrounding gas at 1 atmosphere. The emission spectral lines from the plasma weremore » detected by the OMA system. It was found that metal including heavy metals can surely be detected, thus implying the potent of LIBS technique as a fast screening tools of tsunami sediment contamination.« less

Shapes of Nonbuoyant Round Luminous Hydrocarbon/Air Laminar Jet Diffusion Flames

NASA Technical Reports Server (NTRS)

Lin, K.-C.; Faeth, G. M.; Sunderland, P. B.; Urban, D. L.; Yuan, Z.-G.

1999-01-01

The shapes (luminous flame boundaries) of round luminous nonbuoyant soot-containing hydrocarbon/air laminar jet diffusion flames at microgravity were found from color video images obtained on orbit in the Space Shuttle Columbia. Test conditions included ethylene- and propane-fueled flames burning in still air at an ambient temperature of 300 K, ambient pressures of 35-130 kPa, initial jet diameters of 1.6 and 2.7 mm, and jet exit Reynolds numbers of 45-170. Present test times were 100-200 s and yielded steady axisymmetric flames that were close to the laminar smoke point (including flames both emitting and not emitting soot) with luminous flame lengths of 15-63 mm. The present soot-containing flames had larger luminous flame lengths than earlier ground-based observations having similar burner configurations: 40% larger than the luminous flame lengths of soot-containing low gravity flames observed using an aircraft (KC-135) facility due to reduced effects of accelerative disturbances and unsteadiness; roughly twice as large as the luminous flame lengths of soot-containing normal gravity flames due to the absence of effects of buoyant mixing and roughly twice as large as the luminous flame lengths of soot-free low gravity flames observed using drop tower facilities due to the presence of soot luminosity and possible reduced effects of unsteadiness. Simplified expressions to estimate the luminous flame boundaries of round nonbuoyant laminar jet diffusion flames were obtained from the classical analysis of Spalding (1979); this approach provided Successful Correlations of flame shapes for both soot-free and soot-containing flames, except when the soot-containing flames were in the opened-tip configuration that is reached at fuel flow rates near and greater than the laminar smoke point fuel flow rate.

Shapes of Nonbuoyant Round Luminous Hydrocarbon/Air Laminar Jet Diffusion Flames. Appendix H

NASA Technical Reports Server (NTRS)

Lin, K.-C.; Faeth, G. M.; Sunderland, P. B.; Urban, D. L.; Yuan, Z.-G.; Ross, Howard B. (Technical Monitor)

2000-01-01

The shapes (luminous flame boundaries) of round luminous nonbuoyant soot-containing hydrocarbon/air laminar jet diffusion flames at microgravity were found from color video images obtained on orbit in the Space Shuttle Columbia. Test conditions included ethylene- and propane-fueled flames burning in still air at an ambient temperature of 300 K ambient pressures of 35-130 kPa, initial jet diameters of 1.6 and 2.7 mm, and jet exit Reynolds numbers of 45-170. Present test times were 100-200 s and yielded steady axisymmetric flames that were close to the laminar smoke point (including flames both emitting and not emitting soot) with luminous flame lengths of 15-63 mm. The present soot-containing flames had larger luminous flame lengths than earlier ground-based observations having similar burner configurations: 40% larger than the luminous flame lengths of soot-containing low gravity flames observed using an aircraft (KC-135) facility due to reduced effects of accelerative disturbances and unsteadiness; roughly twice as large as the luminous flame lengths of soot-containing normal gravity flames due to the absence of effects of buoyant mixing and roughly twice as large as the luminous flame lengths of soot-free low gravity flames observed using drop tower facilities due to the presence of soot luminosity and possible reduced effects of unsteadiness, Simplified expressions to estimate the luminous flame boundaries of round nonbuoyant laminar jet diffusion flames were obtained from the classical analysis of Spalding; this approach provided successful correlations of flame shapes for both soot-free and soot-containing flames, except when the soot-containing flames were in the opened-tip configuration that is reached at fuel flow rates near and greater than the laminar smoke point fuel flow rate.

Chicks use changes in luminance and chromatic contrast as indicators of the sign of defocus

PubMed Central

Rucker, Frances J.; Wallman, Josh

2012-01-01

As the eye changes focus, the resulting changes in cone contrast are associated with changes in color and luminance. Color fluctuations should simulate the eye being hyperopic and make the eye grow in the myopic direction, while luminance fluctuations should simulate myopia and make the eye grow in the hyperopic direction. Chicks without lenses were exposed daily (9 a.m. to 5 p.m.) for three days on two consecutive weeks to 2 Hz sinusoidally modulated illumination (mean illuminance of 680 lux) to one of the following: in-phase modulated luminance flicker (LUM), counterphase-modulated red/green (R/G Color) or blue/yellow flicker (B/Y Color), combined color and luminance flicker (Color + LUM), reduced amplitude luminance flicker (Low LUM), or no flicker. After the three-day exposure to flicker, chicks were kept in a brooder under normal diurnal lighting for four days. Changes in the ocular components were measured with ultrasound and with a Hartinger Coincidence Refractometer (aus Jena, Jena, East Germany. After the first three-day exposure, luminance flicker produced more hyperopic refractions (LUM: 2.27 D) than did color flicker (R/G Color: 0.09 D; B/Y Color: −0.25 D). Changes in refraction were mainly due to changes in eye length, with color flicker producing much greater changes in eye length than luminance flicker (R/G Color: 102 μm; B/Y Color: 98 μm; LUM: 66 μm). Our results support the hypothesis that the eye can differentiate between hyperopic and myopic defocus on the basis of the effects of change in luminance or color contrast. PMID:22715194

Ancestry as a potential modifier of gene expression in breast tumors from Colombian women

PubMed Central

Serrano-Gómez, Silvia J.; Sanabria-Salas, María Carolina; Garay, Jone; Baddoo, Melody C.; Hernández-Suarez, Gustavo; Mejía, Juan Carlos; García, Oscar; Miele, Lucio

2017-01-01

Background Hispanic/Latino populations are a genetically admixed and heterogeneous group, with variable fractions of European, Indigenous American and African ancestries. The molecular profile of breast cancer has been widely described in non-Hispanic Whites but equivalent knowledge is lacking in Hispanic/Latinas. We have previously reported that the most prevalent breast cancer intrinsic subtype in Colombian women was Luminal B as defined by St. Gallen 2013 criteria. In this study we explored ancestry-associated differences in molecular profiles of Luminal B tumors among these highly admixed women. Methods We performed whole-transcriptome RNA-seq analysis in 42 Luminal tumors (21 Luminal A and 21 Luminal B) from Colombian women. Genetic ancestry was estimated from a panel of 80 ancestry-informative markers (AIM). We categorized patients according to Luminal subtype and to the proportion of European and Indigenous American ancestry and performed differential expression analysis comparing Luminal B against Luminal A tumors according to the assigned ancestry groups. Results We found 5 genes potentially modulated by genetic ancestry: ERBB2 (log2FC = 2.367, padj<0.01), GRB7 (log2FC = 2.327, padj<0.01), GSDMB (log2FC = 1.723, padj<0.01, MIEN1 (log2FC = 2.195, padj<0.01 and ONECUT2 (log2FC = 2.204, padj<0.01). In the replication set we found a statistical significant association between ERBB2 expression with Indigenous American ancestry (p = 0.02, B = 3.11). This association was not biased by the distribution of HER2+ tumors among the groups analyzed. Conclusions Our results suggest that genetic ancestry in Hispanic/Latina women might modify ERBB2 gene expression in Luminal tumors. Further analyses are needed to confirm these findings and explore their prognostic value. PMID:28832682

Prognostics Health Management Model for LED Package Failure Under Contaminated Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lall, Pradeep; Zhang, Hao; Davis, J Lynn

2015-06-06

The reliability consideration of LED products includes both luminous flux drop and color shift. Previous research either talks about luminous maintenance or color shift, because luminous flux degradation usually takes very long time to observe. In this paper, the impact of a VOC (volatile organic compound) contaminated luminous flux and color stability are examined. As a result, both luminous degradation and color shift had been recorded in a short time. Test samples are white, phosphor-converted, high-power LED packages. Absolute radiant flux is measured with integrating sphere system to calculate the luminous flux. Luminous flux degradation and color shift distance weremore » plotted versus aging time to show the degradation pattern. A prognostic health management (PHM) method based on the state variables and state estimator have been proposed in this paper. In this PHM framework, unscented kalman filter (UKF) was deployed as the carrier of all states. During the estimation process, third order dynamic transfer function was used to implement the PHM framework. Both of the luminous flux and color shift distance have been used as the state variable with the same PHM framework to exam the robustness of the method. Predicted remaining useful life is calculated at every measurement point to compare with the tested remaining useful life. The result shows that state estimator can be used as the method for the PHM of LED degradation with respect to both luminous flux and color shift distance. The prediction of remaining useful life of LED package, made by the states estimator and data driven approach, falls in the acceptable error-bounds (20%) after a short training of the estimator.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lall, Pradeep; Zang, Hao; Davis, J Lynn

The reliability of LED products may be affected by both luminous flux drop and color shift. Previous research on the topic focuses on either luminous maintenance or color shift. However, luminous flux degradation usually takes very long time to observe in LEDs under normal operating conditions. In this paper, the impact of a VOC (volatile organic compound) contaminated luminous flux and color stability are examined. As a result, both luminous degradation and color shift had been recorded in a short time. Test samples are white, phosphorconverted, high-power LED packages. Absolute radiant flux is measured with integrating sphere system to calculatemore » the luminous flux. Luminous flux degradation and color shift distance were plotted versus aging time to show the degradation pattern. A prognostic health management (PHM) method based on the state variables and state estimator have been proposed in this paper. In this PHM framework, unscented kalman filter (UKF) was deployed as the carrier of all states. During the estimation process, third order dynamic transfer function was used to implement the PHM framework. Both of the luminous flux and color shift distance have been used as the state variable with the same PHM framework to exam the robustness of the method. Predicted remaining useful life is calculated at every measurement point to compare with the tested remaining useful life. The result shows that state estimator can be used as the method for the PHM of LED degradation with respect to both luminous flux and color shift distance. The prediction of remaining useful life of LED package, made by the states estimator and data driven approach, falls in the acceptable errorbounds (20%) after a short training of the estimator.« less

High-luminance LEDs replace incandescent lamps in new applications

NASA Astrophysics Data System (ADS)

Evans, David L.

1997-04-01

The advent of high luminance AlInGaP and InGaN LED technologies has prompted the use of LED devices in new applications formally illuminated by incandescent lamps. The luminous efficiencies of these new LED technologies equals or exceeds that attainable with incandescent sources, with reliability factors that far exceed those of incandescent sources. The need for a highly efficient, dependable, and cost effective replacement for incandescent lamps is being fulfilled with high luminance LED lamps. This paper briefly described some of the new applications incorporating high luminance LED lamps, traffic signals and roadway signs for traffic management, automotive exterior lighting, active matrix and full color displays for commercial advertising, and commercial aircraft panel lighting and military aircraft NVG compatible lighting.

A new spatial integration method for luminous flux determination of light-emitting diodes

NASA Astrophysics Data System (ADS)

Zhou, Xiaoli; Zhu, Shaolong; Shen, Haiping; Liu, Muqing

2010-10-01

Spatial integrated measurement using an integrating sphere is usually used for the luminous flux determination of light sources. Devices using an integrating sphere are bulky for use on a production assembly line. This paper proposes an alternative spatial integration method for accurately measuring the total luminous flux of light-emitting diodes (LEDs) having no backward emission. A compound parabolic concentrator is introduced to collect the light from an LED in conjunction with a detector which in turn measures the luminous flux. The study reported here combines both modeling and experiment to show the applicability of this novel method. The uncertainty in the measurements is then evaluated for the total luminous flux measurement from an LED.

Dependence of chromatic responses in V1 on visual field eccentricity and spatial frequency: an fMRI study.

PubMed

D'Souza, Dany V; Auer, Tibor; Frahm, Jens; Strasburger, Hans; Lee, Barry B

2016-03-01

Psychophysical sensitivity to red-green chromatic modulation decreases with visual eccentricity, compared to sensitivity to luminance modulation, even after appropriate stimulus scaling. This is likely to occur at a central, rather than a retinal, site. Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to stimuli designed to separately stimulate different afferent channels' [red-green, luminance, and short-wavelength (S)-cone] circular gratings were recorded as a function of visual eccentricity (±10  deg) and spatial frequency (SF) in human primary visual cortex (V1) and further visual areas (V2v, V3v). In V1, the SF tuning of BOLD fMRI responses became coarser with eccentricity. For red-green and luminance gratings, similar SF tuning curves were found at all eccentricities. The pattern for S-cone modulation differed, with SF tuning changing more slowly with eccentricity than for the other two modalities. This may be due to the different retinal distribution with eccentricity of this receptor type. A similar pattern held in V2v and V3v. This would suggest that transformation or spatial filtering of the chromatic (red-green) signal occurs beyond these areas.

Role of interleukin 10 in norfloxacin prevention of luminal free endotoxin translocation in mice with cirrhosis.

PubMed

Gómez-Hurtado, Isabel; Moratalla, Alba; Moya-Pérez, Ángela; Peiró, Gloria; Zapater, Pedro; González-Navajas, José M; Giménez, Paula; Such, José; Sanz, Yolanda; Francés, Rubén

2014-10-01

Bacterial endotoxin is present in patients with advanced cirrhosis and can induce an immunogenic response without an overt infection. Norfloxacin is a gram-negative bactericidal drug able to maintain low endotoxin levels and stimulate IL-10 production. We aimed at investigating the role of IL-10 in decreasing endotoxin absorption in cirrhotic mice treated with norfloxacin. Cirrhosis was induced by carbon tetrachloride or bile duct ligation in wild type and IL10-deficient mice with or without norfloxacin prior to an intragastrical administration of E. coli, K. pneumonia or E. faecalis. Spontaneous and induced bacterial translocation, free endotoxin and cytokine levels were evaluated in mesenteric lymph nodes. Intestinal permeability was followed by fluorimetry and barrier integrity markers were measured in disrupted intestinal samples. The inflammatory-modulating mechanism was characterized in purified intestinal mononuclear cells. Norfloxacin reduced spontaneous and induced MLN positive-cultures in wild type and IL-10-deficient animals. However, reduction of free endotoxin levels was associated with norfloxacin in wild type but not in IL-10-deficient mice. Wild type but not IL-10-deficient mice treated with norfloxacin significantly normalized intestinal permeability and improved gut barrier integrity markers. The toll-like receptor 4-mediated pro-inflammatory milieu was modulated by norfloxacin in a concentration-dependent manner in cultured intestinal mononuclear cells of wild type mice but not of IL-10-deficient mice. The restoration of IL-10 levels in IL-10-deficient animals reactivated the norfloxacin effect on inflammatory-modulation, gut barrier permeability, and luminal endotoxin absorption. Norfloxacin not only reduces gram-negative intestinal flora but also participates in an IL-10-driven modulation of gut barrier permeability, thus reducing luminal free endotoxin absorption in experimental cirrhosis. Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

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

PubMed

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

2012-03-01

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

Signs of depth-luminance covariance in 3-D cluttered scenes.

PubMed

Scaccia, Milena; Langer, Michael S

2018-03-01

In three-dimensional (3-D) cluttered scenes such as foliage, deeper surfaces often are more shadowed and hence darker, and so depth and luminance often have negative covariance. We examined whether the sign of depth-luminance covariance plays a role in depth perception in 3-D clutter. We compared scenes rendered with negative and positive depth-luminance covariance where positive covariance means that deeper surfaces are brighter and negative covariance means deeper surfaces are darker. For each scene, the sign of the depth-luminance covariance was given by occlusion cues. We tested whether subjects could use this sign information to judge the depth order of two target surfaces embedded in 3-D clutter. The clutter consisted of distractor surfaces that were randomly distributed in a 3-D volume. We tested three independent variables: the sign of the depth-luminance covariance, the colors of the targets and distractors, and the background luminance. An analysis of variance showed two main effects: Subjects performed better when the deeper surfaces were darker and when the color of the target surfaces was the same as the color of the distractors. There was also a strong interaction: Subjects performed better under a negative depth-luminance covariance condition when targets and distractors had different colors than when they had the same color. Our results are consistent with a "dark means deep" rule, but the use of this rule depends on the similarity between the color of the targets and color of the 3-D clutter.

Specific protein supplementation using soya, casein or whey differentially affects regional gut growth and luminal growth factor bioactivity in rats; implications for the treatment of gut injury and stimulating repair.

PubMed

Marchbank, Tania; Mandir, Nikki; Calnan, Denis; Goodlad, Robert A; Podas, Theo; Playford, Raymond J

2018-01-24

Modulation of regional growth within specific segments of the bowel may have clinical value for several gastrointestinal conditions. We therefore examined the effects of different dietary protein sources on regional gut growth and luminal growth factor bioactivity as potential therapies. Rats were fed for 14 days on isonitrogenous and isocaloric diets comprising elemental diet (ED) alone (which is known to cause gut atrophy), ED supplemented with casein or whey or a soya protein-rich feed. Effects on regional gut growth and intraluminal growth factor activity were then determined. Despite calorie intake being similar in all groups, soya rich feed caused 20% extra total body weight gain. Stomach weight was highest on soya and casein diets. Soya enhanced diet caused greatest increase in small intestinal weight and preserved luminal growth factor activity at levels sufficient to increase proliferation in vitro. Regional small intestinal proliferation was highest in proximal segment in ED fed animals whereas distal small intestine proliferation was greater in soya fed animals. Colonic weight and proliferation throughout the colon was higher in animals receiving soya or whey supplemented feeds. We conclude that specific protein supplementation with either soya, casein or whey may be beneficial to rest or increase growth in different regions of the bowel through mechanisms that include differentially affecting luminal growth factor bioactivity. These results have implications for targeting specific regions of the bowel for conditions such as Crohn's disease and chemotherapy.

Host Galaxies Of Luminous Z ˜ 0.6 Quasars: Major Mergers Are Not Prevalent At The Highest Agn Luminosities

NASA Astrophysics Data System (ADS)

Villforth, Carolin; Hamilton, T.; Pawlik, M. M.; Hewlett, T.; Rowlands, K.; Herbst, H.; Shankar, F.; Fontana, A.; Hamann, F.; Koekemoer, A.; Pforr, J.; Trump, J.; Wuyts, S.

2017-06-01

Galaxy interactions are thought to be one of the main triggers of active galactic nuclei (AGN), especially at high luminosities, where the accreted gas mass during the AGN lifetime is substantial. Evidence for a connection between mergers and AGN, however, remains mixed. Possible triggering mechanisms remain particularly poorly understood for luminous AGN, which are thought to require triggering by major mergers, rather than secular processes. We analyse the host galaxies of a sample of 20 optically and X-ray selected luminous AGN (log(Lbol [erg s-1]) > 45) at z ˜ 0.6 using Hubble Space Telescope Wide Field Camera 3 data in the F160W/H band. 15/20 sources have resolved host galaxies. We create a control sample of mock AGN by matching the AGN host galaxies to a control sample of non-AGN galaxies. Visual signs of disturbances are found in about 25 per cent of sources in both the AGN hosts and control galaxies. Using both visual classification and quantitative morphology measures, we show that the levels of disturbance are not enhanced when compared to a matched control sample. We find no signs that major mergers play a dominant role in triggering AGN at high luminosities, suggesting that minor mergers and secular processes dominate AGN triggering up to the highest AGN luminosities. The upper limit on the enhanced fraction of major mergers is ≤20 per cent. While major mergers might increase the incidence of luminous AGN, they are not the prevalent triggering mechanism in the population of unobscured AGN.

Host galaxies of luminous z ˜ 0.6 quasars: major mergers are not prevalent at the highest AGN luminosities

NASA Astrophysics Data System (ADS)

Villforth, C.; Hamilton, T.; Pawlik, M. M.; Hewlett, T.; Rowlands, K.; Herbst, H.; Shankar, F.; Fontana, A.; Hamann, F.; Koekemoer, A.; Pforr, J.; Trump, J.; Wuyts, S.

2017-04-01

Galaxy interactions are thought to be one of the main triggers of active galactic nuclei (AGN), especially at high luminosities, where the accreted gas mass during the AGN lifetime is substantial. Evidence for a connection between mergers and AGN, however, remains mixed. Possible triggering mechanisms remain particularly poorly understood for luminous AGN, which are thought to require triggering by major mergers, rather than secular processes. We analyse the host galaxies of a sample of 20 optically and X-ray selected luminous AGN (log(Lbol [erg s-1]) > 45) at z ˜ 0.6 using Hubble Space Telescope Wide Field Camera 3 data in the F160W/H band. 15/20 sources have resolved host galaxies. We create a control sample of mock AGN by matching the AGN host galaxies to a control sample of non-AGN galaxies. Visual signs of disturbances are found in about 25 per cent of sources in both the AGN hosts and control galaxies. Using both visual classification and quantitative morphology measures, we show that the levels of disturbance are not enhanced when compared to a matched control sample. We find no signs that major mergers play a dominant role in triggering AGN at high luminosities, suggesting that minor mergers and secular processes dominate AGN triggering up to the highest AGN luminosities. The upper limit on the enhanced fraction of major mergers is ≤20 per cent. While major mergers might increase the incidence of luminous AGN, they are not the prevalent triggering mechanism in the population of unobscured AGN.

Metabolic biomarkers for response to PI3K inhibition in basal-like breast cancer

PubMed Central

2013-01-01

Introduction The phosphatidylinositol 3-kinase (PI3K) pathway is frequently activated in cancer cells through numerous mutations and epigenetic changes. The recent development of inhibitors targeting different components of the PI3K pathway may represent a valuable treatment alternative. However, predicting efficacy of these drugs is challenging, and methods for therapy monitoring are needed. Basal-like breast cancer (BLBC) is an aggressive breast cancer subtype, frequently associated with PI3K pathway activation. The objectives of this study were to quantify the PI3K pathway activity in tissue sections from xenografts representing basal-like and luminal-like breast cancer before and immediately after treatment with PI3K inhibitors, and to identify metabolic biomarkers for treatment response. Methods Tumor-bearing animals (n = 8 per treatment group) received MK-2206 (120 mg/kg/day) or BEZ235 (50 mg/kg/day) for 3 days. Activity in the PI3K/Akt/mammalian target of rapamycin pathway in xenografts and human biopsies was evaluated using a novel method for semiquantitative assessment of Aktser473 phosphorylation. Metabolic changes were assessed by ex vivo high-resolution magic angle spinning magnetic resonance spectroscopy. Results Using a novel dual near-infrared immunofluorescent imaging method, basal-like xenografts had a 4.5-fold higher baseline level of pAktser473 than luminal-like xenografts. Following treatment, basal-like xenografts demonstrated reduced levels of pAktser473 and decreased proliferation. This correlated with metabolic changes, as both MK-2206 and BEZ235 reduced lactate concentration and increased phosphocholine concentration in the basal-like tumors. BEZ235 also caused increased glucose and glycerophosphocholine concentrations. No response to treatment or change in metabolic profile was seen in luminal-like xenografts. Analyzing tumor sections from five patients with BLBC demonstrated that two of these patients had an elevated pAktser473 level. Conclusion The activity of the PI3K pathway can be determined in tissue sections by quantitative imaging using an antibody towards pAktser473. Long-term treatment with MK-2206 or BEZ235 resulted in significant growth inhibition in basal-like, but not luminal-like, xenografts. This indicates that PI3K inhibitors may have selective efficacy in basal-like breast cancer with increased PI3K signaling, and identifies lactate, phosphocholine and glycerophosphocholine as potential metabolic biomarkers for early therapy monitoring. In human biopsies, variable pAktser473 levels were observed, suggesting heterogeneous PI3K signaling activity in BLBC. PMID:23448424

Quantitative diffusion weighted imaging parameters in tumor and peritumoral stroma for prediction of molecular subtypes in breast cancer

NASA Astrophysics Data System (ADS)

He, Ting; Fan, Ming; Zhang, Peng; Li, Hui; Zhang, Juan; Shao, Guoliang; Li, Lihua

2018-03-01

Breast cancer can be classified into four molecular subtypes of Luminal A, Luminal B, HER2 and Basal-like, which have significant differences in treatment and survival outcomes. We in this study aim to predict immunohistochemistry (IHC) determined molecular subtypes of breast cancer using image features derived from tumor and peritumoral stroma region based on diffusion weighted imaging (DWI). A dataset of 126 breast cancer patients were collected who underwent preoperative breast MRI with a 3T scanner. The apparent diffusion coefficients (ADCs) were recorded from DWI, and breast image was segmented into regions comprising the tumor and the surrounding stromal. Statistical characteristics in various breast tumor and peritumoral regions were computed, including mean, minimum, maximum, variance, interquartile range, range, skewness, and kurtosis of ADC values. Additionally, the difference of features between each two regions were also calculated. The univariate logistic based classifier was performed for evaluating the performance of the individual features for discriminating subtypes. For multi-class classification, multivariate logistic regression model was trained and validated. The results showed that the tumor boundary and proximal peritumoral stroma region derived features have a higher performance in classification compared to that of the other regions. Furthermore, the prediction model using statistical features, difference features and all the features combined from these regions generated AUC values of 0.774, 0.796 and 0.811, respectively. The results in this study indicate that ADC feature in tumor and peritumoral stromal region would be valuable for estimating the molecular subtype in breast cancer.

Tube formation by complex cellular processes in Ciona intestinalis notochord.

PubMed

Dong, Bo; Horie, Takeo; Denker, Elsa; Kusakabe, Takehiro; Tsuda, Motoyuki; Smith, William C; Jiang, Di

2009-06-15

In the course of embryogenesis multicellular structures and organs are assembled from constituent cells. One structural component common to many organs is the tube, which consists most simply of a luminal space surrounded by a single layer of epithelial cells. The notochord of ascidian Ciona forms a tube consisting of only 40 cells, and serves as a hydrostatic "skeleton" essential for swimming. While the early processes of convergent extension in ascidian notochord development have been extensively studied, the later phases of development, which include lumen formation, have not been well characterized. Here we used molecular markers and confocal imaging to describe tubulogenesis in the developing Ciona notochord. We found that during tubulogenesis each notochord cell established de novo apical domains, and underwent a mesenchymal-epithelial transition to become an unusual epithelial cell with two opposing apical domains. Concomitantly, extracellular luminal matrix was produced and deposited between notochord cells. Subsequently, each notochord cell simultaneously executed two types of crawling movements bi-directionally along the anterior/posterior axis on the inner surface of notochordal sheath. Lamellipodia-like protrusions resulted in cell lengthening along the anterior/posterior axis, while the retraction of trailing edges of the same cell led to the merging of the two apical domains. As a result, the notochord cells acquired endothelial-like shape and formed the wall of the central lumen. Inhibition of actin polymerization prevented the cell movement and tube formation. Ciona notochord tube formation utilized an assortment of common and fundamental cellular processes including cell shape change, apical membrane biogenesis, cell/cell adhesion remodeling, dynamic cell crawling, and lumen matrix secretion.

Spitzer IRS Spectroscopy of the 10 Myr-Old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial Zone

NASA Technical Reports Server (NTRS)

Currie, Thayne; Lisse, Carey M.; Sicillia-Aguilar, Aurora; Rieke, George H.; Su, Kate Y. L.

2011-01-01

We describe Spitzer IRS spectroscopic observations of the approx. 10 Myr-old star, EF Chao Compositional modeling of the spectra from 5 micron to 35 micron confirms that it is surrounded by a luminous debris disk with L(sub D)/L(sub *) approx. 10(exp -3), containing dust with temperatures between 225 K and 430 K characteristic of the terrestrial zone. The EF Cha spectrum shows evidence for many solid-state features, unlike most cold, low-luminosity debris disks but like some other 10-20 Myr-old luminous, warm debris disks (e.g. HD 113766A). The EF Cha debris disk is unusually rich in a species or combination of species whose emissivities resemble that of finely-powdered, laboratory-measured phyllosilicate species (talc, saponite, and smectite), which are likely produced by aqueous alteration of primordial anhydrous rocky materials. The dust and, by inference, the parent bodies of the debris also contain abundant amorphous silicates and metal sulfides, and possibly water ice. The dust's total olivine to pyroxene ratio of approx. 2 also provides evidence of aqueous alteration. The large mass volume of grains with sizes comparable to or below the radiation blow-out limit implies that planetesimals may be colliding at a rate high enough to yield the emitting dust but not so high as to devolatize the planetesimals via impact processing. Because phyllosilicates are produced by the interactions between anhydrous rock and warm, reactive water, EF Cha's disk is a likely signpost for water delivery to the terrestrial zone of a young planetary system.

Radiation-pressure-driven dust waves inside bursting interstellar bubbles

NASA Astrophysics Data System (ADS)

Ochsendorf, B. B.; Verdolini, S.; Cox, N. L. J.; Berné, O.; Kaper, L.; Tielens, A. G. G. M.

2014-06-01

Massive stars drive the evolution of the interstellar medium through their radiative and mechanical energy input. After their birth, they form "bubbles" of hot gas surrounded by a dense shell. Traditionally, the formation of bubbles is explained through the input of a powerful stellar wind, even though direct evidence supporting this scenario is lacking. Here we explore the possibility that interstellar bubbles seen by the Spitzer- and Herschel space telescopes, blown by stars with log (L/L⊙) ≲ 5.2, form and expand because of the thermal pressure that accompanies the ionization of the surrounding gas. We show that density gradients in the natal cloud or a puncture in the swept-up shell lead to an ionized gas flow through the bubble into the general interstellar medium, which is traced by a dust wave near the star, which demonstrates the importance of radiation pressure during this phase. Dust waves provide a natural explanation for the presence of dust inside H II bubbles, offer a novel method to study dust in H II regions and provide direct evidence that bubbles are relieving their pressure into the interstellar medium through a champagne flow, acting as a probe of the radiative interaction of a massive star with its surroundings. We explore a parameter space connecting the ambient density, the ionizing source luminosity, and the position of the dust wave, while using the well studied H II bubbles RCW 120 and RCW 82 as benchmarks of our model. Finally, we briefly examine the implications of our study for the environments of super star clusters formed in ultraluminous infrared galaxies, merging galaxies, and the early Universe, which occur in very luminous and dense environments and where radiation pressure is expected to dominate the dynamical evolution.

Super-Eddington Accretion in the Ultraluminous X-Ray Source NGC 1313 X-2: An Ephemeral Feast

NASA Astrophysics Data System (ADS)

Weng, Shan-Shan; Zhang, Shuang-Nan; Zhao, Hai-Hui

2014-01-01

We investigate the X-ray spectrum, variability, and the surrounding ionized bubble of NGC 1313 X-2 to explore the physics of super-Eddington accretion. Beyond the Eddington luminosity, the accretion disk of NGC 1313 X-2 is truncated at a large radius (~50 times the innermost stable circular orbit), and displays the similar evolution track with both luminous Galactic black-hole and neutron star X-ray binaries (XRBs). In super-critical accretion, the speed of radiatively driven outflows from the inner disk is mildly relativistic. Such ultra-fast outflows would be overionized and might produce weak Fe K absorption lines, which may be detected by the coming X-ray mission Astro-H. If NGC 1313 X-2 is a massive stellar XRB, the high luminosity indicates that an ephemeral feast is held in the source. That is, the source must be accreting at a hyper-Eddington mass rate to give the super-Eddington emission over ~104-105 yr. The expansion of the surrounding bubble nebula with a velocity of ~100 km s-1 might indicate that it has existed over ~106 yr and is inflated by the radiatively driven outflows from the transient with a duty cycle of activity of ~ a few percent. Alternatively, if the surrounding bubble nebula is produced by line-driven winds, less energy is required than the radiatively driven outflow scenario, and the radius of the Strömgren radius agrees with the nebula size. Our results are in favor of the line-driven winds scenario, which can avoid the conflict between the short accretion age and the apparently much longer bubble age inferred from the expansion velocity in the nebula.

Visibility of Active Galactic Nuclei in the Illustris Simulation

NASA Astrophysics Data System (ADS)

Hutchinson-Smith, Tenley; Kelley, Luke; Moreno, Jorge; Hernquist, Lars; Illustris Collaboration

2018-01-01

Active galactic nuclei (AGN) are the very bright, luminous regions surrounding supermassive black holes (SMBH) located at the centers of galaxies. Supermassive black holes are the source of AGN feedback, which occurs once the SMBH reaches a certain critical mass. Almost all large galaxies contain a SMBH, but SMBH binaries are extremely rare. Finding these binary systems are important because it can be a source of gravitational waves if the two SMBH collide. In order to study supermassive black holes, astronomers will often rely on the AGN’s light in order to locate them, but this can be difficult due to the extinction of light caused by the dust and gas surrounding the AGN. My research project focuses on determining the fraction of light we can observe from galactic centers using the Illustris simulation, one of the most advanced cosmological simulations of the universe which was created using a hydrodynamic code and consists of a moving mesh. Measuring the fraction of light observable from galactic centers will help us know what fraction of the time we can observe dual and binary AGN in different galaxies, which would also imply a binary SMBH system. In order to find how much light is being blocked or scattered by the gas and dust surrounding the AGN, we calculated the density of the gas and dust along the lines of sight. I present results including the density of gas along different lines of sight and how it correlates with the image of the galaxy. Future steps include taking an average of the column densities for all the galaxies in Illustris and studying them as a function of galaxy type (before merger, during merger, and post-merger), which will give us information on how this can also affect the AGN luminosity.

Long time stability of lamps with nanostructural carbon field emission cathodes

NASA Astrophysics Data System (ADS)

Kalenik, J.; Firek, P.; Szmidt, J.; Czerwosz, E.; Kozłowski, M.; Stepińska, I.; Wódka, T.

2017-08-01

A luminescent lamp with field emission cathode was constructed and tested. Phosphor excited by electrons from field emission cathode is the source of light. The cathode is covered with nickel-carbon film containing multilayer carbon nanotubes that enhance electron emission from the cathode. Results of luminance stability measurements are presented. Luminance of elaborated luminance lamp is high enough for lighting application. Long term stability (1000 hours) is satisfactory for mass lamp application. Initial short time decrease of luminance is still too high and it needs reduction.

Psychological Effect of Daylighting on Behavior

NASA Astrophysics Data System (ADS)

Oyama, Yoshie

In order to facilitate use of daylighting in architectural design, we tried to measure the suitability of luminous environment for various behavior, including not only visual work but also refreshing and rest. An experiment was conducted with 7 luminous conditions including daylighting. The suitability of a luminous environment was measured by asking the subjects to select suitable activities and unsuitable behaviors from a given list of possible activities. The result showed the selection of unsuitable behaviors was more useful than the selection of suitable behaviors. Furthermore, lighting installations offering a steady luminous environments, were not suitable for many behaviors including refreshing and rest. The luminous environments which were bright but had some fluctuation and some non-uniformity of brightness, obtained by use of direct sunlight, were judged to be suitable for negotiating, refreshing, and meeting.

When do luminance changes capture attention?

PubMed

Spehar, Branka; Owens, Caleb

2012-05-01

In two experiments, we examined the ability of task-irrelevant changes in luminance to capture attention in an irrelevant singleton search. By using uniform increment and decrement arrays, we were able to create changes of the same absolute magnitude, but resulting in a singleton with either higher or lower contrast magnitude, relative to other elements in the search array. A condition where a singleton changed contrast polarity without a concomitant change in the overall contrast magnitude was also included. It was found that only luminance changes resulting in a singleton having increased contrast (or saliency) were effective in capturing attention. In addition, no attentional capture was observed when the irrelevant singleton was characterized by the equivalent amount of static luminance differences, suggesting a unique attentional prioritization of luminance changes that increase singleton saliency.

Study on the luminous characteristics of a natural ball lightning

NASA Astrophysics Data System (ADS)

Wang, Hao; Yuan, Ping; Cen, Jianyong; Liu, Guorong

2018-02-01

According to the optical images of the whole process of a natural ball lightning recorded by two slit-less spectrographs in the Qinghai plateau of China, the simulated observation experiment on the luminous intensity of the spherical light source was carried out. The luminous intensity and the optical power of the natural ball lightning in the wavelength range of 400-690 nm were estimated based on the experimental data and the Lambert-Beer Law. The results show that the maximum luminous intensity was about 1.24 × 105 cd in the initial stage of the natural ball lightning, and the maximum luminous intensity and the maximum optical power in most time of its life were about 5.9 × 104 cd and 4.2 × 103 W, respectively.

Luminous Efficiency Estimates of Meteors. II. Application to Canadian Automated Meteor Observatory Meteor Events

NASA Astrophysics Data System (ADS)

Subasinghe, Dilini; Campbell-Brown, Margaret

2018-02-01

Luminous efficiency is a necessary parameter for determining meteoroid mass from optical emission. Despite this importance, it is very poorly known, with previous results varying by up to two orders of magnitude for a given speed. We present the most recent study of luminous efficiency values determined with modern high-resolution instruments, by directly comparing dynamic and photometric meteoroid masses. Fifteen non-fragmenting meteoroids were used, with a further five clearly fragmenting events for comparison. Twelve of the fifteen non-fragmenting meteoroids had luminous efficiencies less than 1%, while the fragmenting meteoroids had upper limits of a few tens of per cent. No clear trend with speed was seen, but there was a weak negative trend of luminous efficiency on meteoroid mass, implying that smaller meteoroids radiate more efficiently.

Simultaneous chromatic and luminance human electroretinogram responses.

PubMed

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

2012-07-01

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

Neuronal mechanisms underlying differences in spatial resolution between darks and lights in human vision.

PubMed

Pons, Carmen; Mazade, Reece; Jin, Jianzhong; Dul, Mitchell W; Zaidi, Qasim; Alonso, Jose-Manuel

2017-12-01

Artists and astronomers noticed centuries ago that humans perceive dark features in an image differently from light ones; however, the neuronal mechanisms underlying these dark/light asymmetries remained unknown. Based on computational modeling of neuronal responses, we have previously proposed that such perceptual dark/light asymmetries originate from a luminance/response saturation within the ON retinal pathway. Consistent with this prediction, here we show that stimulus conditions that increase ON luminance/response saturation (e.g., dark backgrounds) or its effect on light stimuli (e.g., optical blur) impair the perceptual discrimination and salience of light targets more than dark targets in human vision. We also show that, in cat visual cortex, the magnitude of the ON luminance/response saturation remains relatively constant under a wide range of luminance conditions that are common indoors, and only shifts away from the lowest luminance contrasts under low mesopic light. Finally, we show that the ON luminance/response saturation affects visual salience mostly when the high spatial frequencies of the image are reduced by poor illumination or optical blur. Because both low luminance and optical blur are risk factors in myopia, our results suggest a possible neuronal mechanism linking myopia progression with the function of the ON visual pathway.

Neuronal mechanisms underlying differences in spatial resolution between darks and lights in human vision

PubMed Central

Pons, Carmen; Mazade, Reece; Jin, Jianzhong; Dul, Mitchell W.; Zaidi, Qasim; Alonso, Jose-Manuel

2017-01-01

Artists and astronomers noticed centuries ago that humans perceive dark features in an image differently from light ones; however, the neuronal mechanisms underlying these dark/light asymmetries remained unknown. Based on computational modeling of neuronal responses, we have previously proposed that such perceptual dark/light asymmetries originate from a luminance/response saturation within the ON retinal pathway. Consistent with this prediction, here we show that stimulus conditions that increase ON luminance/response saturation (e.g., dark backgrounds) or its effect on light stimuli (e.g., optical blur) impair the perceptual discrimination and salience of light targets more than dark targets in human vision. We also show that, in cat visual cortex, the magnitude of the ON luminance/response saturation remains relatively constant under a wide range of luminance conditions that are common indoors, and only shifts away from the lowest luminance contrasts under low mesopic light. Finally, we show that the ON luminance/response saturation affects visual salience mostly when the high spatial frequencies of the image are reduced by poor illumination or optical blur. Because both low luminance and optical blur are risk factors in myopia, our results suggest a possible neuronal mechanism linking myopia progression with the function of the ON visual pathway. PMID:29196762

Luminance requirements for lighted signage

NASA Astrophysics Data System (ADS)

Freyssinier, Jean Paul; Narendran, Nadarajah; Bullough, John D.

2006-08-01

Light-emitting diode (LED) technology is presently targeted to displace traditional light sources in backlighted signage. The literature shows that brightness and contrast are perhaps the two most important elements of a sign that determine its attention-getting capabilities and its legibility. Presently, there are no luminance standards for signage, and the practice of developing brighter signs to compete with signs in adjacent businesses is becoming more commonplace. Sign luminances in such cases may far exceed what people usually need for identifying and reading a sign. Furthermore, the practice of higher sign luminance than needed has many negative consequences, including higher energy use and light pollution. To move toward development of a recommendation for lighted signage, several laboratory human factors evaluations were conducted. A scale model of a storefront was used to present human subjects with a typical red channel-letter sign at luminances ranging from 8 cd/m2 to 1512 cd/m2 under four background luminances typical of nighttime outdoor and daytime inside-mall conditions (1, 100, 300, 1000 cd/m2), from three scaled viewing distances (30, 60, 340 ft), and either in isolation or adjacent to two similar signs. Subjects rated the brightness, acceptability, and ease of reading of the test sign for each combination of sign and background luminances and scaled viewing distances.

The role of luminance and chromatic cues in emmetropisation.

PubMed

Rucker, Frances J

2013-05-01

At birth most, but not all eyes, are hyperopic. Over the course of the first few years of life the refraction gradually becomes close to zero through a process called emmetropisation. This process is not thought to require accommodation, though a lag of accommodation has been implicated in myopia development, suggesting that the accuracy of accommodation is an important factor. This review will cover research on accommodation and emmetropisation that relates to the ability of the eye to use colour and luminance cues to guide the responses. There are three ways in which changes in luminance and colour contrast could provide cues: (1) The eye could maximize luminance contrast. Monochromatic light experiments have shown that the human eye can accommodate and animal eyes can emmetropise using changes in luminance contrast alone. However, by reducing the effectiveness of luminance cues in monochromatic and white light by introducing astigmatism, or by reducing light intensity, investigators have revealed that the eye also uses colour cues in emmetropisation. (2) The eye could compare relative cone contrast to derive the sign of defocus information from colour cues. Experiments involving simulations of the retinal image with defocus have shown that relative cone contrast can provide colour cues for defocus in accommodation and emmetropisation. In the myopic simulation the contrast of the red component of a sinusoidal grating was higher than that of the green and blue component and this caused relaxation of accommodation and reduced eye growth. In the hyperopic simulation the contrast of the blue component was higher than that of the green and red components and this caused increased accommodation and increased eye growth. (3) The eye could compare the change in luminance and colour contrast as the eye changes focus. An experiment has shown that changes in colour or luminance contrast can provide cues for defocus in emmetropisation. When the eye is exposed to colour flicker the eye grows almost twice as much, and becomes more myopic, compared to when the eye is exposed to luminance flicker. Neural responses of the luminance and colour mechanisms direct accommodation and emmetropisation mechanisms to different focal planes. Therefore, it is likely that the set point of refraction and accommodation is dependent on the sensitivity of the eye to changes in spatial and temporal, colour and luminance contrast. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

Television image of a large upward electrical discharge above a thunderstorm system

NASA Technical Reports Server (NTRS)

Franz, R. C.; Nemzek, R. J.; Winckler, J. R.

1990-01-01

A low light-level TV camera is used to obtain an unusual image of luminous electrical discharge over a thunderstorm 250 km from the observation site. The image is presented and the discharge in the image is described. It is suggested that the image is probably due to two localized electric charge concentrations at the cloud tops. The hazard of these discharges for aircraft and rocket launches is examined. Consideration is given to the possibility that these discharges may account for unexplained photometric observations of distant lightning events that show a low rise rate of the luminous pulse and no electromagnetic sferic pulse like that in cloud-to-earth lightning strokes. The photometric events of this type that occurred on September 22-23, 1989 during hurricane Hugo are noted.

Quality assurance in mammography: College of Radiology Survey in Malaysia.

PubMed

Ho, E L M; Ng, K H; Wong, J H D; Wang, H B

2006-06-01

Malaysia's mammography QA practice was surveyed based on the Malaysian Ministry of Health and the American College of Radiology (ACR) requirements. Data on mammography unit, processor, image receptor, exposure factors, mean glandular dose (MGD), sensitometry, image quality and viewbox luminance were obtained. Mean developer temperature and cycle time were 34.1 +/- 1.8degreesC and 107.7 +/- 33.2 seconds. Mean base+fog level, speed index and contrast index were 0.20+/-0.01, 1.20+/-0.01 and 1.33+/-0.26 respectively. Eighty-six percent of the fifty centres passed the image quality test while 12.5% complied with ACR recommended viewbox luminance. Average MGD was 1.0+/-0.4 mGy. Malaysia is on the right track for QA but with room for total quality improvement.

Object Lesson: Discovering and Learning to Recognize Objects

DTIC Science & Technology

2002-01-01

4 x 4 grid represents the possible appearance of an edge, quantized to just two luminance levels. The dark line centered in the grid is the average...11):33-38, 1995. [16] Maja J. Mataric . A distributed model for mobile robot environment-learning and navigation. Technical Report AIlR- 1228

Insights on Information Absorption and Transmission Rates in C2I Settings

DTIC Science & Technology

1985-09-01

Development Activity, Ft Leavenworth, KS, 1978. Craik , F.I.M., and Lockhart , R.S. Levels of processing : A framework for memory research. Journal of Verbal... Craik & Lockhart , 1972; Baddeley, 1978). However, the idea is that the resulting information is relegated to central processing and thereby brought to...SYSTEM 9 ambient conditions: * luminence level , legibility t2 Information Processing : e training decoding, translating/trans- USER 0 experience scribing

Behavioral evaluation of visual function of rats using a visual discrimination apparatus.

PubMed

Thomas, Biju B; Samant, Deedar M; Seiler, Magdalene J; Aramant, Robert B; Sheikholeslami, Sharzad; Zhang, Kevin; Chen, Zhenhai; Sadda, SriniVas R

2007-05-15

A visual discrimination apparatus was developed to evaluate the visual sensitivity of normal pigmented rats (n=13) and S334ter-line-3 retinal degenerate (RD) rats (n=15). The apparatus is a modified Y maze consisting of two chambers leading to the rats' home cage. Rats were trained to find a one-way exit door leading into their home cage, based on distinguishing between two different visual alternatives (either a dark background or black and white stripes at varying luminance levels) which were randomly displayed on the back of each chamber. Within 2 weeks of training, all rats were able to distinguish between these two visual patterns. The discrimination threshold of normal pigmented rats was a luminance level of -5.37+/-0.05 log cd/m(2); whereas the threshold level of 100-day-old RD rats was -1.14+/-0.09 log cd/m(2) with considerable variability in performance. When tested at a later age (about 150 days), the threshold level of RD rats was significantly increased (-0.82+/-0.09 log cd/m(2), p<0.03, paired t-test). This apparatus could be useful to train rats at a very early age to distinguish between two different visual stimuli and may be effective for visual functional evaluations following therapeutic interventions.

Restriction Fragment Length Polymorphism Analysis Reveals High Levels of Genetic Divergence Among the Light Organ Symbionts of Flashlight Fish.

PubMed

Wolfe, C J; Haygood, M G

1991-08-01

Restriction fragment length polymorphisms within the lux and 16S ribosomal RNA gene regions were used to compare unculturable bacterial light organ symbionts of several anomalopid fish species. The method of Nei and Li (1979) was used to calculate phylogenetic distance from the patterns of restriction fragment lengths of the luxA and 16S rRNA regions. Phylogenetic trees constructed from each distance matrix (luxA and 16S rDNA data) have similar branching orders. The levels of divergence among the symbionts, relative to other culturable luminous bacteria, suggests that the symbionts differ at the level of species among host fish genera. Symbiont relatedness and host geographic location do not seem to be correlated, and the symbionts do not appear to be strains of common, free-living, luminous bacteria. In addition, the small number of hybridizing fragments within the 16S rRNA region of the symbionts, compared with that of the free-living species, suggests a decrease in copy number of rRNA operons relative to free-living species. At this level of investigation, the symbiont phylogeny is consistent with the proposed phylogeny of the host fish family and suggests that each symbiont strain coevolved with its host fish species.

Patterns of breast cancer relapse in accordance to biological subtype.

PubMed

Ignatov, Atanas; Eggemann, Holm; Burger, Elke; Ignatov, Tanja

2018-04-19

To evaluate the pattern of recurrence of breast cancer according to its biological subtype in a large cohort of patients treated with therapy representative of current practice. Patients treated between 2000 and 2016 with known biological subtype were eligible. Data were prospectively collected. Primary endpoint was the subtype-dependent pattern and time of recurrence. Loco-regional and distant site and time of recurrence were assessed. Median follow-up time was 80.8 months. For 12,053 (82.5%) of 14,595 patients with primary non-metastatic invasive breast cancer a subtype classification was possible. The luminal A subtype had the highest 10-year survival followed by luminal B and luminal/HER2. The worst survival demonstrated HER2 enriched and TNBC. HER2 and TNBC had the highest rate of recurrence in the first 5 years, whereas the rate of recurrence for luminal A and luminal B tumors was initially low, but remained continuously even after 10 years of follow-up. Luminal A tumors demonstrated the lowest rate of distant metastases predominantly in bone. So did luminal B tumors. HER2 enriched subtype was characterized with increased rate of loco-regional recurrence and distant metastases in bone, liver and brain. Luminal/HER2 had pattern of relapse similar to HER2 enriched tumors, with exception of loco-regional relapse and brain metastases. TNBC had higher rate of lung, bone and brain metastases as well as loco-regional relapse. Breast cancer subtypes are associated with different time and pattern of recurrence and it should be considered during treatment decision.

Fabrication and properties of light-emitting diodes based on self-assembled multilayers of poly(phenylene vinylene)

NASA Astrophysics Data System (ADS)

Fou, A. C.; Onitsuka, O.; Ferreira, M.; Rubner, M. F.; Hsieh, B. R.

1996-05-01

Light-emitting diodes have been fabricated from self-assembled multilayers of poly(p-phenylene vinylene) (PPV) and two different polyanions; polystyrene sulfonic acid (SPS) and polymethacrylic acid (PMA). The type of polyanion used to assemble the multilayer thin films was found to dramatically influence the behavior and performance of devices fabricated with indium tin oxide and aluminum electrodes. Light-emitting devices fabricated from PMA/PPV multilayers were found to exhibit luminance levels in the range of 20-60 cd/m2, a thickness dependent turn-on voltage and classical rectifying behavior with rectification ratios greater than 105. In sharp contrast, the devices based on SPS/PPV exhibited near symmetric current-voltage curves, thickness independent turn-on voltages and much lower luminance levels. The significant difference in device behavior observed between these two systems is primarily due to a doping effect induced either chemically or electrochemically by the sulfonic acid groups of SPS. It was also found that the performance of these devices depends on the type of layer that is in contact with the Al top electrode thereby making it possible to manipulate device efficiency at the molecular level.

Night myopia is reduced in binocular vision.

PubMed

Chirre, Emmanuel; Prieto, Pedro M; Schwarz, Christina; Artal, Pablo

2016-06-01

Night myopia, which is a shift in refraction with light level, has been widely studied but still lacks a complete understanding. We used a new infrared open-view binocular Hartmann-Shack wave front sensor to quantify night myopia under monocular and natural binocular viewing conditions. Both eyes' accommodative response, aberrations, pupil diameter, and convergence were simultaneously measured at light levels ranging from photopic to scotopic conditions to total darkness. For monocular vision, reducing the stimulus luminance resulted in a progression of the accommodative state that tends toward the subject's dark focus or tonic accommodation and a change in convergence following the induced accommodative error. Most subjects presented a myopic shift of accommodation that was mitigated in binocular vision. The impact of spherical aberration on the focus shift was relatively small. Our results in monocular conditions support the hypothesis that night myopia has an accommodative origin as the eye progressively changes its accommodation state with decreasing luminance toward its resting state in total darkness. On the other hand, binocularity restrains night myopia, possibly by using fusional convergence as an additional accommodative cue, thus reducing the potential impact of night myopia on vision at low light levels.

Compact radio sources in luminous infrared galaxies

NASA Astrophysics Data System (ADS)

Parra, Rodrigo

2007-08-01

Radio interferometry is an observational technique of high sensitivity and incomparably high spatial resolution. Moreover, because radio waves can freely propagate through interstellar dust and gas, it allows the study of regions of the universe completely obscured at other wavelengths. This thesis reports the observational and theoretical results of my research during the past four years which are mostly based on interferometric radio data. The COLA sample is an infrared selected sample of active star forming galaxies. We conducted 6 cm VLA and VLBI snapshot observations of the northern half of this sample. The radio emission seen at VLA scales is consistent with being powered by star formation activity because it follows the far infrared to radio correlation. We detect 22% of the sample sources in our VLBI snapshots. Based on luminosity arguments, we argue that these sub-parsec VLBI sources are powered by AGN activity. Furthermore, we find that VLBI detections are preferentially found in sources whose VLA scale structures have the highest peak brightnesses suggesting a strong correlation between compact starburst and AGN activity. This observational result is consistent with the theoretical picture of an Eddington-limited nuclear starburst acting as the last valve in the pipeline transporting the gas from kiloparsec scales onto the accretion disc of a buried AGN. Arp 220 is the archetypical ultra luminous infrared galaxy. For many years this source has been known to harbour a compact (~100 pc) cluster of unresolved 18 cm bright sources believed to be bright core collapse supernovae. Using multiwavelength VLBI observations, we obtained for the first time radio spectra for 18 of these sources. We find that over a half of them have spectra consistent with young supernovae. The rest can be better explained as older supernova remnants interacting with the high density starburst ISM. This finding allowed us to constrain the number of possible scenarios for the Arp 220 starburst. A subset of luminous infrared galaxies contain non-thermal spectral line emission from the OH radical. These OH megamasers often show diffuse extended (~100 pc) low gain emission surrounding compact ([Special characters omitted. 1 pc) high gain maser spots. These observational features have been explained in terms of unsaturated and saturated masers. Using numerical simulations we have shown how both the diffuse and compact components of the OH megamaser observed towards the luminous infrared galaxy IIIZw35 can be explained by a single phase of unsaturated maser clouds in which the compact bright masers are caused by the random line-of-sight overlap of several such clouds and the diffuse component by the beam spatial average of many low gain clouds too weak to be seen independently. The theoretical tools developed to analyse this particular case have been extended to the general problem of propagation of radiation in clumpy media.

Image quality degradation by light-scattering processes in high-performance display devices for medical imaging

NASA Astrophysics Data System (ADS)

Badano, Aldo

1999-11-01

This thesis addresses the characterization of light scattering processes that degrade image quality in high performance electronic display devices for digital radiography. Using novel experimental and computational tools, we study the lateral diffusion of light in emissive display devices that causes extensive veiling glare and significant reduction of the physical contrast. In addition, we examine the deleterious effects of ambient light reflections that affect the contrast of low luminance regions, and superimpose unwanted structured signal. The analysis begins by introducing the performance limitations of the human visual system to define high fidelity requirements. It is noted that current devices severely suffer from image quality degradation due to optical transport processes. To model the veiling glare and reflectance characteristics of display devices, we introduce a Monte Carlo light transport simulation code, DETECT-II, that tracks individual photons through multiple scattering events. The simulation accounts for the photon polarization state at each scattering event, and provides descriptions for rough surfaces and thin film coatings. A new experimental method to measure veiling glare is described next, based on a conic collimated probe that minimizes contamination from bright areas. The measured veiling glare ratio is taken to be the luminance in the surrounding bright field divided by the luminance in the dark circle. We show that veiling glare ratios in the order of a few hundreds can be measured with an uncertainty of a few percent. The veiling glare response function is obtained by measuring the small spot contrast ratio of test patterns having varying dark spot radius. Using DETECT-II, we then estimate the ring response functions for a high performance medical imaging monitor of current design, and compare the predictions of the model with the experimentally measured response function. The data presented in this thesis demonstrate that although absorption in the faceplate of high performance monochrome cathode-ray tube monitors have reduced glare, a black matrix design is needed for high fidelity applications. For a high performance medical imaging monitor with anti-reflective coating, the glare ratio for a 1 cm diameter dark spot was measured to be 240. Finally, we introduce experimental techniques for measurements of specular and diffuse display reflectance, and we compare measured reflection coefficients with Monte Carlo estimates. A specular reflection coefficient of 0.0012, and a diffuse coefficient of 0.005 nits/lux are required to minimize degradation from ambient light in rooms with 100 lux illumination. In spite of having comparable reflection coefficients, the low maximum luminance of current devices worsens the effect of ambient light reflections when compared to radiographic film. Flat panel technologies with optimized designs can perform even better than film due to a thin faceplate, increased light absorption, and high brightness.

Covariation of Color and Luminance Facilitate Object Individuation in Infancy

ERIC Educational Resources Information Center

Woods, Rebecca J.; Wilcox, Teresa

2010-01-01

The ability to individuate objects is one of our most fundamental cognitive capacities. Recent research has revealed that when objects vary in color or luminance alone, infants fail to individuate those objects until 11.5 months. However, color and luminance frequently covary in the natural environment, thus providing a more salient and reliable…

Paracrine Met signaling triggers epithelial–mesenchymal transition in mammary luminal progenitors, affecting their fate

PubMed Central

Di-Cicco, Amandine; Petit, Valérie; Chiche, Aurélie; Bresson, Laura; Romagnoli, Mathilde; Orian-Rousseau, Véronique; Vivanco, Maria dM; Medina, Daniel; Faraldo, Marisa M; Glukhova, Marina A; Deugnier, Marie-Ange

2015-01-01

HGF/Met signaling has recently been associated with basal-type breast cancers, which are thought to originate from progenitor cells residing in the luminal compartment of the mammary epithelium. We found that ICAM-1 efficiently marks mammary luminal progenitors comprising hormone receptor-positive and receptor-negative cells, presumably ductal and alveolar progenitors. Both cell populations strongly express Met, while HGF is produced by stromal and basal myoepithelial cells. We show that persistent HGF treatment stimulates the clonogenic activity of ICAM1-positive luminal progenitors, controlling their survival and proliferation, and leads to the expression of basal cell characteristics, including stem cell potential. This is accompanied by the induction of Snai1 and Snai2, two major transcription factors triggering epithelial–mesenchymal transition, the repression of the luminal-regulatory genes Elf5 and Hey1, and claudin down-regulation. Our data strongly indicate that paracrine Met signaling can control the function of luminal progenitors and modulate their fate during mammary development and tumorigenesis. DOI: http://dx.doi.org/10.7554/eLife.06104.001 PMID:26165517

MicroRNA-200, associated with metastatic breast cancer, promotes traits of mammary luminal progenitor cells.

PubMed

Sánchez-Cid, Lourdes; Pons, Mònica; Lozano, Juan José; Rubio, Nuria; Guerra-Rebollo, Marta; Soriano, Aroa; Paris-Coderch, Laia; Segura, Miquel F; Fueyo, Raquel; Arguimbau, Judit; Zodda, Erika; Bermudo, Raquel; Alonso, Immaculada; Caparrós, Xavier; Cascante, Marta; Rafii, Arash; Kang, Yibin; Martínez-Balbás, Marian; Weiss, Stephen J; Blanco, Jerónimo; Muñoz, Montserrat; Fernández, Pedro L; Thomson, Timothy M

2017-10-13

MicroRNAs are critical regulators of gene networks in normal and abnormal biological processes. Focusing on invasive ductal breast cancer (IDC), we have found dysregulated expression in tumor samples of several microRNAs, including the miR-200 family, along progression from primary tumors to distant metastases, further reflected in higher blood levels of miR-200b and miR-7 in IDC patients with regional or distant metastases relative to patients with primary node-negative tumors. Forced expression of miR-200s in MCF10CA1h mammary cells induced an enhanced epithelial program, aldehyde dehydrogenase (ALDH) activity, mammosphere growth and ability to form branched tubuloalveolar structures while promoting orthotopic tumor growth and lung colonization in vivo . MiR-200s also induced the constitutive activation of the PI3K-Akt signaling through downregulation of PTEN, and the enhanced mammosphere growth and ALDH activity induced in MCF10CA1h cells by miR-200s required the activation of this signaling pathway. Interestingly, the morphology of tumors formed in vivo by cells expressing miR-200s was reminiscent of metaplastic breast cancer (MBC). Indeed, the epithelial components of MBC samples expressed significantly higher levels of miR-200s than their mesenchymal components and displayed a marker profile compatible with luminal progenitor cells. We propose that microRNAs of the miR-200 family promote traits of highly proliferative breast luminal progenitor cells, thereby exacerbating the growth and metastatic properties of transformed mammary epithelial cells.

Characterizing visual asymmetries in contrast perception using shaded stimuli.

PubMed

Chacón, José; Castellanos, Miguel Ángel; Serrano-Pedraza, Ignacio

2015-01-01

Previous research has shown a visual asymmetry in shaded stimuli where the perceived contrast depended on the polarity of their dark and light areas (Chacón, 2004). In particular, circles filled out with a top-dark luminance ramp were perceived with higher contrast than top-light ones although both types of stimuli had the same physical contrast. Here, using shaded stimuli, we conducted four experiments in order to find out if the perceived contrast depends on: (a) the contrast level, (b) the type of shading (continuous vs. discrete) and its degree of perceived three-dimensionality, (c) the orientation of the shading, and (d) the sign of the perceived contrast alterations. In all experiments the observers' tasks were to equate the perceived contrast of two sets of elements (usually shaded with opposite luminance polarity), in order to determine the subjective equality point. Results showed that (a) there is a strong difference in perceived contrast between circles filled out with luminance ramp top-dark and top-light that is similar for different contrast levels; (b) we also found asymmetries in contrast perception with different shaded stimuli, and this asymmetry was not related with the perceived three-dimensionality but with the type of shading, being greater for continuous-shading stimuli; (c) differences in perceived contrast varied with stimulus orientation, showing the maximum difference on vertical axis with a left bias consistent with the bias found in previous studies that used visual-search tasks; and (d) asymmetries are consistent with an attenuation in perceived contrast that is selective for top-light vertically-shaded stimuli.

Display of high dynamic range images under varying viewing conditions

NASA Astrophysics Data System (ADS)

Borer, Tim

2017-09-01

Recent demonstrations of high dynamic range (HDR) television have shown that superb images are possible. With the emergence of an HDR television production standard (ITU-R Recommendation BT.2100) last year, HDR television production is poised to take off. However research to date has focused principally on HDR image display only under "dark" viewing conditions. HDR television will need to be displayed at varying brightness and under varying illumination (for example to view sport in daytime or on mobile devices). We know, from common practice with conventional TV, that the rendering intent (gamma) should change under brighter conditions, although this is poorly quantified. For HDR the need to render images under varying conditions is all the more acute. This paper seeks to explore the issues surrounding image display under varying conditions. It also describes how visual adaptation is affected by display brightness, surround illumination, screen size and viewing distance. Existing experimental results are presented and extended to try to quantify these effects. Using the experimental results it is described how HDR images may be displayed so that they are perceptually equivalent under different viewing conditions. A new interpretation of the experimental results is reported, yielding a new, luminance invariant model for the appropriate display "gamma". In this way the consistency of HDR image reproduction should be improved, thereby better maintaining "creative intent" in television.

Luminous Efficiency of Hypervelocity Meteoroid Impacts on the Moon Derived from the 2015 Geminid Meteor Shower

NASA Technical Reports Server (NTRS)

Moser, D. E.; Suggs, R. M.; Ehlert, S. R.

2017-01-01

Meteoroids cannot be observed directly because of their small size. In-situ measurements of the meteoroid environment are rare and have very small collecting areas. The Moon, in contrast, has a large collecting area and therefore can be used as a large meteoroid detector for gram-kilogram sized particles. Meteoroids striking the Moon create an impact flash observable by Earth-based telescopes. Their kinetic energy is converted to luminous energy with some unknown luminous efficiency ?(v), which is likely a function of meteoroid velocity (among other factors). This luminous efficiency is imperative to calculating the kinetic energy and mass of the meteoroid, as well as meteoroid fluxes, and it cannot be determined in the laboratory at meteoroid speeds and sizes due to mechanical constraints. Since laboratory simulations fail to resolve the luminous efficiency problem, observations of the impact flash itself must be utilized. Meteoroids associated with specific meteor showers have known speed and direction, which simplifies the determination of the luminous efficiency. NASA has routinely monitored the Moon for impact flashes since early 2006 [1]. During this time, several meteor showers have produced multiple impact flashes on the Moon, yielding a sufficient sample of impact flashes with which to perform a luminous efficiency analysis similar to that outlined in Bellot Rubio et al. [2, 3] and further described by Moser et al. [4], utilizing Earth-based measurements of the shower flux and mass index. The Geminid meteor shower has produced the most impact flashes in the NASA dataset to date with over 80 detections. More than half of these Geminids were recorded in 2015 (locations pictured in Fig. 1), and may represent the largest single-shower impact flash sample known. This work analyzes the 2015 Geminid lunar impacts and calculates their luminous efficiency. The luminous efficiency is then applied to calculate the kinetic energies and mass-es of these shower meteoroids.

Associations between sociodemographic and clinicopathological factors, and breast cancer subtypes in a population-based study

PubMed Central

Llanos, Adana A.M.; Chandwani, Sheenu; Bandera, Elisa V.; Hirshfield, Kim M.; Lin, Yong; Ambrosone, Christine B.; Demissie, Kitaw

2015-01-01

Purpose This study examines the factors distinguishing breast cancer (BC) subtypes. Methods We examined subtypes in 629 women with invasive BC, diagnosed from 2006–2012 and enrolled in an epidemiological study in New Jersey. Using molecular characteristics from pathology reports, BCs were categorized as luminal A, luminal B, non-luminal HER2-expressing, or triple-negative breast cancer [TNBC] subtypes. Multinomial logistic models (luminal A as referent) were used to describe BC subtype associations. Results Women with luminal B tumors were more likely to be younger at diagnosis (Odds ratio [OR] 1.8, 95% confidence interval [CI] 1.0–3.4) and to have higher grade (OR 2.6, 95% CI 1.5–4.7), larger (OR 1.9, 95% CI 1.0–3.6), and Ki67 positive tumors (OR 2.1, 95% CI 1.1–4.0). Women with non-luminal HER2-expressing BCs were more likely to have higher grade tumors (OR 14.5, 95% CI 5.3–39.7). Women with TNBCs were more likely to be African American (OR 1.9, 95% CI 1.0–3.4) and to have higher grade (Or 9.7, 95% CI 5.1–18.4), larger (OR 2.2, 95% CI 1.0–4.8), and Ki67 positive (OR 2.9, 95% CI 1.6–5.2) tumors. Notably, compared to the luminal A subtype, luminal B, non-luminal HER2-expressing and triple-negative subtypes were more frequently self-detected; however, these associations were attenuated in multivariable models. Conclusions These findings suggest that some BC subtypes were associated with features denoting more aggressive phenotypes, namely higher grade, larger size, and Ki67 positivity, and possibly patient self-detection among some women. These findings highlight a need for enhanced screening, particularly among younger women, racial/ethnic minorities and lower socioeconomic subgroups. PMID:26376894

Breast Cancer Subtypes and Response to Docetaxel in Node-Positive Breast Cancer: Use of an Immunohistochemical Definition in the BCIRG 001 Trial

PubMed Central

Hugh, Judith; Hanson, John; Cheang, Maggie Chon U.; Nielsen, Torsten O.; Perou, Charles M.; Dumontet, Charles; Reed, John; Krajewska, Maryla; Treilleux, Isabelle; Rupin, Matthieu; Magherini, Emmanuelle; Mackey, John; Martin, Miguel; Vogel, Charles

2009-01-01

Purpose To investigate the prognostic and predictive significance of subtyping node-positive early breast cancer by immunohistochemistry in a clinical trial of a docetaxel-containing regimen. Methods Pathologic data from a central laboratory were available for 1,350 patients (91%) from the BCIRG 001 trial of docetaxel, doxorubicin, and cyclophosphamide (TAC) versus fluorouracil, doxorubicin, and cyclophosphamide (FAC) for operable node-positive breast cancer. Patients were classified by tumor characteristics as (1) triple negative (estrogen receptor [ER]–negative, progesterone receptor [PR]–negative, HER2/neu [HER2]–negative), (2) HER2 (HER2-positive, ER-negative, PR-negative), (3) luminal B (ER-positive and/or PR-positive and either HER2-positive and/or Ki67high), and (4) luminal A (ER-positive and/or PR-positive and not HER2-positive or Ki67high), and assessed for prognostic significance and response to adjuvant chemotherapy. Results Patients were subdivided into triple negative (14.5%), HER2 (8.5%), luminal B (61.1%), and luminal A (15.9%). Three-year disease-free survival (DFS) rates (P values with luminal B as referent) were 67% (P < .0001), 68% (P = .0008), 82% (referent luminal B), and 91% (P = .0027), respectively, with hazard ratios of 2.22, 2.12, and 0.46. Improved 3-year DFS with TAC was found in the luminal B group (P = .025) and a combined ER-positive/HER2-negative group treated with tamoxifen (P = .041), with a marginal trend in the triple negatives (P = .051) and HER2 (P = .068) subtypes. No DFS advantage was seen in the luminal A population. Conclusion A simple immunopanel can divide breast cancers into biologic subtypes with strong prognostic effects. TAC significantly complements endocrine therapy in patients with luminal B subtype and, in the absence of targeted therapy, is effective in the triple-negative population. PMID:19204205

Detection of the Light Organ Symbiont, Vibrio fischeri, in Hawaiian Seawater by Using lux Gene Probes †

PubMed Central

Lee, Kyu-Ho; Ruby, Edward G.

1992-01-01

Symbiotic bacteria that inhabit the light-emitting organ of the Hawaiian squid Euprymna scolopes are distinctive from typical Vibrio fischeri organisms in that they are not visibly luminous when grown in laboratory culture. Therefore, the abundance of these bacteria in seawater samples cannot be estimated simply by identifying them among luminous colonies that arise on nutrient agar plates. Instead, we have used luxR and polymerase chain reaction generated luxA gene probes to identify both luminous and non-visibly luminous V. fischeri colonies by DNA-DNA hybridization. The probes were specific, hybridizing at least 50 to 100 times more strongly to immobilized DNAs from V. fischeri strains than to those of pure cultures of other related species. Thus, even non-visibly luminous V. fischeri colonies could be identified among colonies obtained from natural seawater samples by their probe-positive reaction. Bacteria in seawater samples, obtained either within or distant from squid habitats, were collected on membrane filters and incubated until colonies appeared. The filters were then observed for visibly luminous V. fischeri colonies and hybridized with the lux gene probes to determine the number of total V. fischeri colonies (both luminous and non-visibly luminous). We detected no significant differences in the abundance of luminous V. fischeri CFU in any of the water samples observed (≤1 to 3 CFU/100 ml). However, probe-positive colonies of V. fischeri (up to 900 CFU/100 ml) were found only in seawater collected from within the natural habitats of the squids. A number of criteria were used to confirm that these probe-positive strains were indistinguishable from symbiotic V. fischeri. Therefore, the luxA and luxR gene probes were species specific and gave a reliable estimate of the number of culturable V. fischeri colonies in natural water samples. Images PMID:16348678

Detection of the Light Organ Symbiont, Vibrio fischeri, in Hawaiian Seawater by Using lux Gene Probes.

PubMed

Lee, K H; Ruby, E G

1992-03-01

Symbiotic bacteria that inhabit the light-emitting organ of the Hawaiian squid Euprymna scolopes are distinctive from typical Vibrio fischeri organisms in that they are not visibly luminous when grown in laboratory culture. Therefore, the abundance of these bacteria in seawater samples cannot be estimated simply by identifying them among luminous colonies that arise on nutrient agar plates. Instead, we have used luxR and polymerase chain reaction generated luxA gene probes to identify both luminous and non-visibly luminous V. fischeri colonies by DNA-DNA hybridization. The probes were specific, hybridizing at least 50 to 100 times more strongly to immobilized DNAs from V. fischeri strains than to those of pure cultures of other related species. Thus, even non-visibly luminous V. fischeri colonies could be identified among colonies obtained from natural seawater samples by their probe-positive reaction. Bacteria in seawater samples, obtained either within or distant from squid habitats, were collected on membrane filters and incubated until colonies appeared. The filters were then observed for visibly luminous V. fischeri colonies and hybridized with the lux gene probes to determine the number of total V. fischeri colonies (both luminous and non-visibly luminous). We detected no significant differences in the abundance of luminous V. fischeri CFU in any of the water samples observed (

Chemosensitivity and Endocrine Sensitivity in Clinical Luminal Breast Cancer Patients in the Prospective Neoadjuvant Breast Registry Symphony Trial (NBRST) Predicted by Molecular Subtyping.

PubMed

Whitworth, Pat; Beitsch, Peter; Mislowsky, Angela; Pellicane, James V; Nash, Charles; Murray, Mary; Lee, Laura A; Dul, Carrie L; Rotkis, Michael; Baron, Paul; Stork-Sloots, Lisette; de Snoo, Femke A; Beatty, Jennifer

2017-03-01

Hormone receptor-positive (HR+) tumors have heterogeneous biology and present a challenge for determining optimal treatment. In the Neoadjuvant Breast Registry Symphony Trial (NBRST) patients were classified according to MammaPrint/BluePrint subtyping to provide insight into the response to neoadjuvant endocrine therapy (NET) or neoadjuvant chemotherapy (NCT). The purpose of this predefined substudy was to compare MammaPrint/BluePrint with conventional 'clinical' immunohistochemistry/fluorescence in situ hybridization (IHC/FISH) subtyping in 'clinical luminal' [HR+/human epidermal growth factor receptor 2-negative (HER2-)] breast cancer patients to predict treatment sensitivity. NBRST IHC/FISH HR+/HER2- breast cancer patients (n = 474) were classified into four molecular subgroups by MammaPrint/BluePrint subtyping: Luminal A, Luminal B, HER2, and Basal type. Pathological complete response (pCR) rates were compared with conventional IHC/FISH subtype. The overall pCR rate for 'clinical luminal' patients to NCT was 11 %; however, 87 of these 474 patients were reclassified as Basal type by BluePrint, with a high pCR rate of 32 %. The MammaPrint index was highly associated with the likelihood of pCR (p < 0.001). Fifty-three patients with BluePrint Luminal tumors received NET with an aromatase inhibitor and 36 (68 %) had a clinical response. With BluePrint subtyping, 18 % of clinical 'luminal' patients are classified in a different subgroup, compared with conventional assessment, and these patients have a significantly higher response rate to NCT compared with BluePrint Luminal patients. MammaPrint/BluePrint subtyping can help allocate effective treatment to appropriate patients. In addition, accurate identification of subtype biology is important in the interpretation of neoadjuvant treatment response since lack of pCR in luminal patients does not portend the worse prognosis associated with residual disease in Basal and HER2 subtypes.

Differentiation Between Luminal-A and Luminal-B Breast Cancer Using Intravoxel Incoherent Motion and Dynamic Contrast-Enhanced Magnetic Resonance Imaging.

PubMed

Kawashima, Hiroko; Miyati, Tosiaki; Ohno, Naoki; Ohno, Masako; Inokuchi, Masafumi; Ikeda, Hiroko; Gabata, Toshifumi

2017-12-01

The study aimed to investigate whether intravoxel incoherent motion (IVIM) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) can differentiate luminal-B from luminal-A breast cancer MATERIALS AND METHODS: Biexponential analyses of IVIM and DCE MRI were performed using a 3.0-T MRI scanner, involving 134 patients with 137 pathologically confirmed luminal-type invasive breast cancers. Luminal-type breast cancer was categorized as luminal-B breast cancer (LBBC, Ki-67 ≧ 14%) or luminal-A breast cancer (LABC, Ki-67 < 14%). Quantitative parameters from IVIM (pure diffusion coefficient [D], perfusion-related diffusion coefficient [D*], and fraction [f]) and DCE MRI (initial percentage of enhancement and signal enhancement ratio [SER]) were calculated. The apparent diffusion coefficient (ADC) was also calculated using monoexponential fitting. We correlated these data with the Ki-67 status. The D and ADC values of LBBC were significantly lower than those of LABC (P = 0.028, P = 0.037). The SER of LBBC was significantly higher than that of LABC (P = 0.004). A univariate analysis showed that a significantly lower D (<0.847 x 10 -3 mm 2 /s), lower ADC (<0.960 × 10 -3 mm 2 /s), and higher SER (>1.071) values were associated with LBBC (all P values <0.01), compared to LABC. In a multivariate analysis, a higher SER (>1.071; odds ratio: 3.0099, 95% confidence interval: 1.4246-6.3593; P = 0.003) value and a lower D (<0.847 × 10 -3 mm 2 /s; odds ratio: 2.6878, 95% confidence interval: 1.0445-6.9162; P = 0.040) value were significantly associated with LBBC, compared to LABC. The SER derived from DCE MRI and the D derived from IVIM are associated independently with the Ki-67 status in patients with luminal-type breast cancer. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Prognostic Significance of Progesterone Receptor–Positive Tumor Cells Within Immunohistochemically Defined Luminal A Breast Cancer

PubMed Central

Prat, Aleix; Cheang, Maggie Chon U.; Martín, Miguel; Parker, Joel S.; Carrasco, Eva; Caballero, Rosalía; Tyldesley, Scott; Gelmon, Karen; Bernard, Philip S.; Nielsen, Torsten O.; Perou, Charles M.

2013-01-01

Purpose Current immunohistochemical (IHC)-based definitions of luminal A and B breast cancers are imperfect when compared with multigene expression-based assays. In this study, we sought to improve the IHC subtyping by examining the pathologic and gene expression characteristics of genomically defined luminal A and B subtypes. Patients and Methods Gene expression and pathologic features were collected from primary tumors across five independent cohorts: British Columbia Cancer Agency (BCCA) tamoxifen-treated only, Grupo Español de Investigación en Cáncer de Mama 9906 trial, BCCA no systemic treatment cohort, PAM50 microarray training data set, and a combined publicly available microarray data set. Optimal cutoffs of percentage of progesterone receptor (PR) –positive tumor cells to predict survival were derived and independently tested. Multivariable Cox models were used to test the prognostic significance. Results Clinicopathologic comparisons among luminal A and B subtypes consistently identified higher rates of PR positivity, human epidermal growth factor receptor 2 (HER2) negativity, and histologic grade 1 in luminal A tumors. Quantitative PR gene and protein expression were also found to be significantly higher in luminal A tumors. An empiric cutoff of more than 20% of PR-positive tumor cells was statistically chosen and proved significant for predicting survival differences within IHC-defined luminal A tumors independently of endocrine therapy administration. Finally, no additional prognostic value within hormonal receptor (HR) –positive/HER2-negative disease was observed with the use of the IHC4 score when intrinsic IHC-based subtypes were used that included the more than 20% PR-positive tumor cells and vice versa. Conclusion Semiquantitative IHC expression of PR adds prognostic value within the current IHC-based luminal A definition by improving the identification of good outcome breast cancers. The new proposed IHC-based definition of luminal A tumors is HR positive/HER2 negative/Ki-67 less than 14%, and PR more than 20%. PMID:23233704

TRPV4 activation mediates flow-induced nitric oxide production in the rat thick ascending limb

PubMed Central

Garvin, Jeffrey L.

2014-01-01

Nitric oxide (NO) regulates renal function. Luminal flow stimulates NO production in the thick ascending limb (TAL). Transient receptor potential vanilloid 4 (TRPV4) is a mechano-sensitive channel activated by luminal flow in different types of cells. We hypothesized that TRPV4 mediates flow-induced NO production in the rat TAL. We measured NO production in isolated, perfused rat TALs using the fluorescent dye DAF FM. Increasing luminal flow from 0 to 20 nl/min stimulated NO from 8 ± 3 to 45 ± 12 arbitrary units (AU)/min (n = 5; P < 0.05). The TRPV4 antagonists, ruthenium red (15 μmol/l) and RN 1734 (10 μmol/l), blocked flow-induced NO production. Also, luminal flow did not increase NO production in the absence of extracellular calcium. We also studied the effect of luminal flow on NO production in TALs transduced with a TRPV4shRNA. In nontransduced TALs luminal flow increased NO production by 47 ± 17 AU/min (P < 0.05; n = 5). Similar to nontransduced TALs, luminal flow increased NO production by 39 ± 11 AU/min (P < 0.03; n = 5) in TALs transduced with a control negative sequence-shRNA while in TRPV4shRNA-transduced TALs, luminal flow did not increase NO production (Δ10 ± 15 AU/min; n = 5). We then tested the effect of two different TRPV4 agonists on NO production in the absence of luminal flow. 4α-Phorbol 12,13-didecanoate (1 μmol/l) enhanced NO production by 60 ± 11 AU/min (P < 0.002; n = 7) and GSK1016790A (10 ηmol/l) increased NO production by 52 ± 15 AU/min (P < 0.03; n = 5). GSK1016790A (10 ηmol/l) did not stimulate NO production in TRPV4shRNA-transduced TALs. We conclude that activation of TRPV4 channels mediates flow-induced NO production in the rat TAL. PMID:24966090

Endogenous flow-induced superoxide stimulates Na/H exchange activity via PKC in thick ascending limbs

PubMed Central

Garvin, Jeffrey L.

2014-01-01

Luminal flow stimulates Na reabsorption along the nephron and activates protein kinase C (PKC) which enhances endogenous superoxide (O2−) production by thick ascending limbs (TALs). Exogenously-added O2− augments TAL Na reabsorption, a process also dependent on PKC. Luminal Na/H exchange (NHE) mediates NaHCO3 reabsorption. However, whether flow-stimulated, endogenously-produced O2− enhances luminal NHE activity and the signaling pathway involved are unclear. We hypothesized that flow-induced production of endogenous O2− stimulates luminal NHE activity via PKC in TALs. Intracellular pH recovery was measured as an indicator of NHE activity in isolated, perfused rat TALs. Increasing luminal flow from 5 to 20 nl/min enhanced total NHE activity from 0.104 ± 0.031 to 0.167 ± 0.036 pH U/min, 81%. The O2− scavenger tempol decreased total NHE activity by 0.066 ± 0.011 pH U/min at 20 nl/min but had no significant effect at 5 nl/min. With the NHE inhibitor EIPA in the bath to block basolateral NHE, tempol reduced flow-enhanced luminal NHE activity by 0.029 ± 0.010 pH U/min, 30%. When experiments were repeated with staurosporine, a nonselective PKC inhibitor, tempol had no effect. Because PKC could mediate both induction of O2− by flow and the effect of O2− on luminal NHE activity, we used hypoxanthine/xanthine oxidase to elevate O2−. Hypoxanthine/xanthine oxidase increased luminal NHE activity by 0.099 ± 0.020 pH U/min, 137%. Staurosporine and the PKCα/β1-specific inhibitor Gö6976 blunted this effect. We conclude that flow-induced O2− stimulates luminal NHE activity in TALs via PKCα/β1. This accounts for part of flow-stimulated bicarbonate reabsorption by TALs. PMID:25080525

Optical coherence tomography investigations of ceramic lumineers

NASA Astrophysics Data System (ADS)

Fernandes, Luana O.; Graça, Natalia D. R. L.; Melo, Luciana S. A.; Silva, Claudio H. V.; Gomes, Anderson S. L.

2016-02-01

Lumineers are veneer laminates used as an alternative for aesthetic dental solutions of the highest quality, but the only current means of its performance assessment is visual inspection. The objective of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain to analyze in vivo in a single patient, 14 lumineers 180 days after cementation. It was possible to observe images in various kinds of changes in the cementing line and the laminate. It was concluded that the OCT is an effective and promising method to clinical evaluation of the cementing line in lumineers.

Assessment of uterine luminal pH in mares and the effect of dilute vinegar lavage on uterine luminal pH and endometrial health.

PubMed

Thompson, Renee L; Gunn, Allan J; Stephen, Cyril P; Ip, Heather; Brookes, Victoria J

2018-05-19

Uterine luminal pH has been demonstrated to be a valid indicator of uterine health in species such as cattle and sheep. However, research regarding uterine luminal pH in equines is lacking. The objectives of this study were to assess uterine luminal pH in mares during the estrous cycle, and evaluate the effect of dilute vinegar lavage on both uterine luminal pH and endometrial health. The study was conducted using a randomized block design in which eight mares (four Thoroughbred and four Standardbred) were aged matched then randomly assigned to two groups. Endometrial biopsies were taken from each mare prior to trial commencement. The treatment group (n = 4; 1 Thoroughbred, 3 Standardbreds) received a uterine lavage of one liter dilute vinegar (20 mL of vinegar in 1 L saline) every second day during each estrus period throughout the trial. Control group mares did not receive a uterine lavage. Uterine luminal pH measurements were recorded in all mares in both groups for a period of up to 10 min immediately prior to lavage (0 h), one hour and 24 h post lavage (same time points in control group mares as if they had been treated). Diestrus uterine luminal pH measurements were recorded once between days 6-10 post-ovulation. Endometrial biopsies were repeated from all mares at trial completion. Mean uterine luminal pH ranged from pH 5.3 to 7.6 and was significantly lower during diestrus compared to estrus (P < 0.001). Regression analysis indicated that this variation in pH was best explained by estrous cycle day, with uterine luminal pH increasing by a mean of 0.03 units each day (P < 0.001) from 6 to 10 days post-ovulation through to ovulation. Uterine lavage with dilute vinegar did not significantly affect uterine luminal pH (P > 0.05). A scoring system to quantify the abundance of cell types in the endometrial biopsies showed that mares in the treatment group had a significant decrease in polymorphonuclear cell abundance between pre- and post-trial biopsies (P = 0.03). Mares in the treatment group also had a significant decrease in lymphocyte, plasma cell and eosinophil cell abundance (P = 0.05). Although dilute vinegar lavage was not associated with a significant change in uterine luminal pH, it was associated with a significant improvement in endometrial biopsy scores. Because the control group did not receive a uterine lavage, further research is required to determine if this significant improvement results from the addition of dilute vinegar, or the uterine lavage itself. Copyright © 2018 Elsevier Inc. All rights reserved.

Visual categorization of natural movies by rats.

PubMed

Vinken, Kasper; Vermaercke, Ben; Op de Beeck, Hans P

2014-08-06

Visual categorization of complex, natural stimuli has been studied for some time in human and nonhuman primates. Recent interest in the rodent as a model for visual perception, including higher-level functional specialization, leads to the question of how rodents would perform on a categorization task using natural stimuli. To answer this question, rats were trained in a two-alternative forced choice task to discriminate movies containing rats from movies containing other objects and from scrambled movies (ordinate-level categorization). Subsequently, transfer to novel, previously unseen stimuli was tested, followed by a series of control probes. The results show that the animals are capable of acquiring a decision rule by abstracting common features from natural movies to generalize categorization to new stimuli. Control probes demonstrate that they did not use single low-level features, such as motion energy or (local) luminance. Significant generalization was even present with stationary snapshots from untrained movies. The variability within and between training and test stimuli, the complexity of natural movies, and the control experiments and analyses all suggest that a more high-level rule based on more complex stimulus features than local luminance-based cues was used to classify the novel stimuli. In conclusion, natural stimuli can be used to probe ordinate-level categorization in rats. Copyright © 2014 the authors 0270-6474/14/3410645-14$15.00/0.

Simultaneous chromatic and luminance human electroretinogram responses

PubMed Central

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

2012-01-01

The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats’ ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing. PMID:22586211

The Effect of Illumination on Gray Color

ERIC Educational Resources Information Center

Da Pos, Osvaldo; Baratella, Linda; Sperandio, Gabriele

2010-01-01

The present study explored the perceptual process of integration of luminance information in the production of the gray color of an object placed in an environment viewed from a window. The mean luminance of the object was varied for each mean luminance of the environment. Participants matched the gray color of the object with that of Munsell…

10 CFR 31.12 - General license for certain items and self-luminous products containing radium-226.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false General license for certain items and self-luminous... LICENSES FOR BYPRODUCT MATERIAL § 31.12 General license for certain items and self-luminous products..., or transfer, in accordance with the provisions of paragraphs (b), (c), and (d) of this section...

10 CFR 31.12 - General license for certain items and self-luminous products containing radium-226.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false General license for certain items and self-luminous... LICENSES FOR BYPRODUCT MATERIAL § 31.12 General license for certain items and self-luminous products..., or transfer, in accordance with the provisions of paragraphs (b), (c), and (d) of this section...

A stent for co-delivering paclitaxel and nitric oxide from abluminal and luminal surfaces: Preparation, surface characterization, and in vitro drug release studies

NASA Astrophysics Data System (ADS)

Gallo, Annemarie; Mani, Gopinath

2013-08-01

Most drug-eluting stents currently available are coated with anti-proliferative drugs on both abluminal (toward blood vessel wall) and luminal (toward lumen) surfaces to prevent neointimal hyperplasia. While the abluminal delivery of anti-proliferative drugs is useful for controlling neointimal hyperplasia, the luminal delivery of such drugs impairs or prevents endothelialization which causes late stent thrombosis. This research is focused on developing a bidirectional dual drug-eluting stent to co-deliver an anti-proliferative agent (paclitaxel - PAT) and an endothelial cell promoting agent (nitric oxide - NO) from abluminal and luminal surfaces of the stent, respectively. Phosphonoacetic acid, a polymer-free drug delivery platform, was initially coated on the stents. Then, the PAT and NO donor drugs were co-coated on the abluminal and luminal stent surfaces, respectively. The co-coating of drugs was collectively confirmed by the surface characterization techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), 3D optical surface profilometry, and contact angle goniometry. SEM showed that the integrity of the co-coating of drugs was maintained without delamination or cracks formation occurring during the stent expansion experiments. In vitro drug release studies showed that the PAT was released from the abluminal stent surfaces in a biphasic manner, which is an initial burst followed by a slow and sustained release. The NO was burst released from the luminal stent surfaces. Thus, this study demonstrated the co-delivery of PAT and NO from abluminal and luminal stent surfaces, respectively. The stent developed in this study has potential applications in inhibiting neointimal hyperplasia as well as encouraging luminal endothelialization to prevent late stent thrombosis.

Accuracy of computed tomographic angiography for stenosis quantification using quantitative coronary angiography or intravascular ultrasound as the gold standard.

PubMed

Joshi, Subodh B; Okabe, Teruo; Roswell, Robert O; Weissman, Gaby; Lopez, Cristian F; Lindsay, Joseph; Pichard, Augusto D; Weissman, Neil J; Waksman, Ron; Weigold, Wm Guy

2009-10-15

Computed tomographic angiography (CTA) is considered to have limited accuracy for quantifying exact percent diameter stenosis in coronary arteries. However, most studies evaluating CTA use quantitative coronary angiography (QCA) as the gold standard, a technique with its own limitations. We sought to determine whether CTA measurements of stenosis severity correlate better with intravascular ultrasound (IVUS) than with QCA. Luminal dimensions of 67 de novo coronary lesions were measured by CTA, IVUS, and QCA. IVUS was performed when lesion severity by angiography was equivocal. Mean percent diameter stenosis by QCA was 51 +/- 9.8% and mean IVUS minimal luminal area was 3.8 +/- 1.8 mm(2). There was a moderate correlation between CTA minimal luminal area and IVUS minimal luminal area (r(2) = 0.41, p <0.001), but no relation between CTA and QCA measurements of minimal luminal diameter (r(2) = 0.01, p = 0.57) or diameter stenosis (r(2) = 0.02, p = 0.31). There was also no relation between IVUS minimal luminal area and QCA diameter stenosis (r(2) = 0.01, p = 0.50). When lesions with moderate or severe calcification were excluded, the correlation between CTA minimal luminal area and IVUS minimal luminal area was good (r(2) = 0.68, p <0.001). In conclusion, in this cohort of patients with intermediate-grade lesions on cardiac catheterization, absolute measurements of stenosis severity on CTA correlated with IVUS but not with QCA. Our findings suggest that limitations of quantitative coronary angiography as a gold standard need to be considered in studies evaluating the accuracy of coronary CTA.

Parafoveal Target Detectability Reversal Predicted by Local Luminance and Contrast Gain Control

NASA Technical Reports Server (NTRS)

Ahumada, Albert J., Jr.; Beard, Bettina L.; Null, Cynthia H. (Technical Monitor)

1996-01-01

This project is part of a program to develop image discrimination models for the prediction of the detectability of objects in a range of backgrounds. We wanted to see if the models could predict parafoveal object detection as well as they predict detection in foveal vision. We also wanted to make our simplified models more general by local computation of luminance and contrast gain control. A signal image (0.78 x 0.17 deg) was made by subtracting a simulated airport runway scene background image (2.7 deg square) from the same scene containing an obstructing aircraft. Signal visibility contrast thresholds were measured in a fully crossed factorial design with three factors: eccentricity (0 deg or 4 deg), background (uniform or runway scene background), and fixed-pattern white noise contrast (0%, 5%, or 10%). Three experienced observers responded to three repetitions of 60 2IFC trials in each condition and thresholds were estimated by maximum likelihood probit analysis. In the fovea the average detection contrast threshold was 4 dB lower for the runway background than for the uniform background, but in the parafovea, the average threshold was 6 dB higher for the runway background than for the uniform background. This interaction was similar across the different noise levels and for all three observers. A likely reason for the runway background giving a lower threshold in the fovea is the low luminance near the signal in that scene. In our model, the local luminance computation is controlled by a spatial spread parameter. When this parameter and a corresponding parameter for the spatial spread of contrast gain were increased for the parafoveal predictions, the model predicts the interaction of background with eccentricity.

The protective effect of supplemental calcium on colonic permeability depends on a calcium phosphate-induced increase in luminal buffering capacity.

PubMed

Schepens, Marloes A A; ten Bruggencate, Sandra J M; Schonewille, Arjan J; Brummer, Robert-Jan M; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg M J

2012-04-01

An increased intestinal permeability is associated with several diseases. Previously, we have shown that dietary Ca decreases colonic permeability in rats. This might be explained by a calcium-phosphate-induced increase in luminal buffering capacity, which protects against an acidic pH due to microbial fermentation. Therefore, we investigated whether dietary phosphate is a co-player in the effect of Ca on permeability. Rats were fed a humanised low-Ca diet, or a similar diet supplemented with Ca and containing either high, medium or low phosphate concentrations. Chromium-EDTA was added as an inert dietary intestinal permeability marker. After dietary adaptation, short-chain fructo-oligosaccharides (scFOS) were added to all diets to stimulate fermentation, acidify the colonic contents and induce an increase in permeability. Dietary Ca prevented the scFOS-induced increase in intestinal permeability in rats fed medium- and high-phosphate diets but not in those fed the low-phosphate diet. This was associated with higher faecal water cytotoxicity and higher caecal lactate levels in the latter group. Moreover, food intake and body weight during scFOS supplementation were adversely affected by the low-phosphate diet. Importantly, luminal buffering capacity was higher in rats fed the medium- and high-phosphate diets compared with those fed the low-phosphate diet. The protective effect of dietary Ca on intestinal permeability is impaired if dietary phosphate is low. This is associated with a calcium phosphate-induced increase in luminal buffering capacity. Dragging phosphate into the colon and thereby increasing the colonic phosphate concentration is at least part of the mechanism behind the protective effect of Ca on intestinal permeability.

TPC2 is a novel NAADP-sensitive Ca2+ release channel, operating as a dual sensor of luminal pH and Ca2+.

PubMed

Pitt, Samantha J; Funnell, Tim M; Sitsapesan, Mano; Venturi, Elisa; Rietdorf, Katja; Ruas, Margarida; Ganesan, A; Gosain, Rajendra; Churchill, Grant C; Zhu, Michael X; Parrington, John; Galione, Antony; Sitsapesan, Rebecca

2010-11-05

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a molecule capable of initiating the release of intracellular Ca(2+) required for many essential cellular processes. Recent evidence links two-pore channels (TPCs) with NAADP-induced release of Ca(2+) from lysosome-like acidic organelles; however, there has been no direct demonstration that TPCs can act as NAADP-sensitive Ca(2+) release channels. Controversial evidence also proposes ryanodine receptors as the primary target of NAADP. We show that TPC2, the major lysosomal targeted isoform, is a cation channel with selectivity for Ca(2+) that will enable it to act as a Ca(2+) release channel in the cellular environment. NAADP opens TPC2 channels in a concentration-dependent manner, binding to high affinity activation and low affinity inhibition sites. At the core of this process is the luminal environment of the channel. The sensitivity of TPC2 to NAADP is steeply dependent on the luminal [Ca(2+)] allowing extremely low levels of NAADP to open the channel. In parallel, luminal pH controls NAADP affinity for TPC2 by switching from reversible activation of TPC2 at low pH to irreversible activation at neutral pH. Further evidence earmarking TPCs as the likely pathway for NAADP-induced intracellular Ca(2+) release is obtained from the use of Ned-19, the selective blocker of cellular NAADP-induced Ca(2+) release. Ned-19 antagonizes NAADP-activation of TPC2 in a non-competitive manner at 1 μM but potentiates NAADP activation at nanomolar concentrations. This single-channel study provides a long awaited molecular basis for the peculiar mechanistic features of NAADP signaling and a framework for understanding how NAADP can mediate key physiological events.

Unusual broad-line Mg II emitters among luminous galaxies in the baryon oscillation spectroscopic survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roig, Benjamin; Blanton, Michael R.; Ross, Nicholas P.

2014-02-01

Many classes of active galactic nuclei (AGNs) have been observed and recorded since the discovery of Seyfert galaxies. In this paper, we examine the sample of luminous galaxies in the Baryon Oscillation Spectroscopic Survey. We find a potentially new observational class of AGNs, one with strong and broad Mg II λ2799 line emission, but very weak emission in other normal indicators of AGN activity, such as the broad-line Hα, Hβ, and the near-ultraviolet AGN continuum, leading to an extreme ratio of broad Hα/Mg II flux relative to normal quasars. Meanwhile, these objects' narrow-line flux ratios reveal AGN narrow-line regions withmore » levels of activity consistent with the Mg II fluxes and in agreement with that of normal quasars. These AGN may represent an extreme case of the Baldwin effect, with very low continuum and high equivalent width relative to typical quasars, but their ratio of broad Mg II to broad Balmer emission remains very unusual. They may also be representative of a class of AGN where the central engine is observed indirectly with scattered light. These galaxies represent a small fraction of the total population of luminous galaxies (≅ 0.1%), but are more likely (about 3.5 times) to have AGN-like nuclear line emission properties than other luminous galaxies. Because Mg II is usually inaccessible for the population of nearby galaxies, there may exist a related population of broad-line Mg II emitters in the local universe which is currently classified as narrow-line emitters (Seyfert 2 galaxies) or low ionization nuclear emission-line regions.« less

Item Banking Enables Stand-Alone Measurement of Driving Ability.

PubMed

Khadka, Jyoti; Fenwick, Eva K; Lamoureux, Ecosse L; Pesudovs, Konrad

2016-12-01

To explore whether large item sets, as used in item banking, enable important latent traits, such as driving, to form stand-alone measures. The 88-item activity limitation (AL) domain of the glaucoma module of the Eye-tem Bank was interviewer-administered to patients with glaucoma. Rasch analysis was used to calibrate all items in AL domain on the same interval-level scale and test its psychometric properties. Based on Rasch dimensionality metrics, the AL scale was separated into subscales. These subscales underwent separate Rasch analyses to test whether they could form stand-alone measures. Independence of these measures was tested with Bland and Altman (B&A) Limit of Agreement (LOA). The AL scale was completed by 293 patients (median age, 71 years). It demonstrated excellent precision (3.12). However, Rasch analysis dimensionality metrics indicated that the domain arguably had other dimensions which were driving, luminance, and reading. Once separated, the remaining AL items, driving and luminance subscales, were unidimensional and had excellent precision of 4.25, 2.94, and 2.22, respectively. The reading subscale showed poor precision (1.66), so it was not examined further. The luminance subscale demonstrated excellent agreement (mean bias, 0.2 logit; 95% LOA, -2.2 to 3.3 logit); however, the driving subscale demonstrated poor agreement (mean bias, 1.1 logit; 95% LOA, -4.8 to 7.0 logit) with the AL scale. These findings indicate that driving items in the AL domain of the glaucoma module were perceived and responded to differently from the other AL items, but the reading and luminance items were not. Therefore, item banking enables stand-alone measurement of driving ability in glaucoma.

Measuring high-resolution sky luminance distributions with a CCD camera.

PubMed

Tohsing, Korntip; Schrempf, Michael; Riechelmann, Stefan; Schilke, Holger; Seckmeyer, Gunther

2013-03-10

We describe how sky luminance can be derived from a newly developed hemispherical sky imager (HSI) system. The system contains a commercial compact charge coupled device (CCD) camera equipped with a fish-eye lens. The projection of the camera system has been found to be nearly equidistant. The luminance from the high dynamic range images has been calculated and then validated with luminance data measured by a CCD array spectroradiometer. The deviation between both datasets is less than 10% for cloudless and completely overcast skies, and differs by no more than 20% for all sky conditions. The global illuminance derived from the HSI pictures deviates by less than 5% and 20% under cloudless and cloudy skies for solar zenith angles less than 80°, respectively. This system is therefore capable of measuring sky luminance with the high spatial and temporal resolution of more than a million pixels and every 20 s respectively.

Intravascular photoacoustic imaging of exogenously labeled atherosclerotic plaque through luminal blood

NASA Astrophysics Data System (ADS)

Yeager, Doug; Karpiouk, Andrei; Wang, Bo; Amirian, James; Sokolov, Konstantin; Smalling, Richard; Emelianov, Stanislav

2012-10-01

Combined intravascular ultrasound and intravascular photoacoustic (IVUS/IVPA) imaging has been previously established as a viable means for assessing atherosclerotic plaque morphological and compositional characteristics using both endogenous and exogenous contrast. In this study, IVUS/IVPA imaging of atherosclerotic rabbit aortas following systemic injection of gold nanorods (AUNRs) with peak absorbance within the tissue optical window is performed. Ex vivo imaging results reveal a high photoacoustic signal from localized AUNRs in regions with atherosclerotic plaques. Corresponding histological staining further confirms the preferential extravasation of AUNRs in atherosclerotic regions with compromised luminal endothelium and acute inflammation. The ability to detect AUNRs using combined IVUS and photoacoustic imaging in the presence of luminal saline and luminal blood is evaluated using both spectroscopic and single wavelength IVPA imaging techniques. Results demonstrate that AUNR detection within the arterial wall can be achieved using both methods, even in the case of imaging through luminal blood.

[Effect of organic and inorganic toxic compounds on luminescence of luminous fungi].

PubMed

Vydriakova, G A; Gusev, A A; Medvedeva, S E

2011-01-01

The possibility of the development of the solid phase bioluminescent biotest using aerial mycelium of the luminous fungi was investigated. Effect of organic and inorganic toxic compounds (TC) at concentrations from 10(-6) to 1 mg/ml on luminescence of aerial mycelia of four species of luminous fungi-Armillaria borealis (Culture Collection of the Institute of Forest, Siberian Branch, Russian Academy of Sciences), A. mellea, A. gallica, and Lampteromyces japonicus (Fungi Collection of the Botanical Institute, Russian Academy of Sciences)--has been studied. Culture of A. mellea was shown to be most sensitive to solutions of the model TC. It was demonstrated that the sensitivity of the luminous fungi is comparable with the sensitivity of the bacteria that are used for environmental monitoring. Use of the aerial mycelium of the luminous fungi on the solid support as a test object is a promising approach in biotesting for the development of continuous biosensors for air monitoring.

ASASSN-15lh: A highly super-luminous supernova

NASA Astrophysics Data System (ADS)

Dong, Subo; Shappee, B. J.; Prieto, J. L.; Jha, S. W.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Thompson, T. A.; Morrell, N.; Thompson, I. B.; Basu, U.; Beacom, J. F.; Bersier, D.; Brimacombe, J.; Brown, J. S.; Bufano, F.; Chen, Ping; Conseil, E.; Danilet, A. B.; Falco, E.; Grupe, D.; Kiyota, S.; Masi, G.; Nicholls, B.; Olivares E., F.; Pignata, G.; Pojmanski, G.; Simonian, G. V.; Szczygiel, D. M.; Woźniak, P. R.

2016-01-01

We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 1045 ergs s-1, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 1052 ergs, challenging the magnetar model for its engine.

Modeling of luminance distribution in CAVE-type virtual reality systems

NASA Astrophysics Data System (ADS)

Meironke, Michał; Mazikowski, Adam

2017-08-01

At present, one of the most advanced virtual reality systems are CAVE-type (Cave Automatic Virtual Environment) installations. Such systems are usually consisted of four, five or six projection screens and in case of six screens arranged in form of a cube. Providing the user with a high level of immersion feeling in such systems is largely dependent of optical properties of the system. The modeling of physical phenomena plays nowadays a huge role in the most fields of science and technology. It allows to simulate work of device without a need to make any changes in the physical constructions. In this paper distribution of luminance in CAVE-type virtual reality systems were modelled. Calculations were performed for the model of 6-walled CAVE-type installation, based on Immersive 3D Visualization Laboratory, situated at the Faculty of Electronics, Telecommunications and Informatics at the Gdańsk University of Technology. Tests have been carried out for two different scattering distribution of the screen material in order to check how these characteristicinfluence on the luminance distribution of the whole CAVE. The basis assumption and simplification of modeled CAVE-type installation and results were presented. The brief discussion about the results and usefulness of developed model were also carried out.

The Large Area KX Quasar Survey: Photometric Redshift Selection and the Complete Quasar Catalogue

NASA Astrophysics Data System (ADS)

Maddox, Natasha; Hewett, P. C.; Peroux, C.

2013-01-01

We have completed a large area, ˜600 square degree, spectroscopic survey for luminous quasars flux-limited in the K-band. The survey utilises the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) in regions of sky within the Sloan Digital Sky Survey (SDSS) footprint. We exploit the K-band excess (KX) of all quasars with respect to Galactic stars in combination with a custom-built photometric redshift/classification scheme to identify quasar candidates for spectroscopic follow-up observations. The survey is complete to K≤16.6, and includes >3200 known quasars from the SDSS, with more than 250 additional confirmed quasars from the KX-selection which eluded the SDSS quasar selection algorithm. The selection is >95% complete with respect to known SDSS quasars and >95% efficient, largely independent of redshift and magnitude. The KX-selected quasars will provide new constraints on the fraction of luminous quasars reddened by dust with E(B-V)≤0.5 mag. Several projects utilizing the KX quasars are ongoing, including a spectroscopic campaign searching for dusty quasar intervening absorption systems. The KX survey is a well-defined sample of quasars useful for investigating the properties of luminous quasars with intermediate levels of dust extinction either within their host galaxies or due to intervening absorption systems.

Improvement of the internal light environment on the objects of transport infrastructure with aid of sun-protective devices

NASA Astrophysics Data System (ADS)

Stetsky, Sergey

2017-10-01

The article analyzes the problems of outdoor stationary sun-protective devices (S.P.D.) and their influence on the natural daylighting levels in the premises of civil objects of transport infrastructure under the hot and sunny climatic conditions of the environment. It is noted, that with clear sky, typical for the said climate, non-uniform luminance of the sky differs seriously from the luminance of standard overcast sky with diffused light, recommended by C.I.E. (Commission International D’Eclairage).A conclusion is made, that with clear sky conditions, a sun-protective devices in the form of stationary canopies (awninas) help to improve the lighting environment in the premises considered. This becomes possible due to reflected sun flow from the surfaces of SPD employed, as well as due to rise of a daylight factor values in farmost from windows zones of interiors, because of the increase of luminance factor values of the sky areas, observed from these zones. Thus, the SPD considered, in the hot and sunny climatic conditions are able not only to carry out their main function of passive method of solar radiation and thermal control in the interiors, but also to act as an efficient measure to improve lightning environment of the premises in question.

The RasGAP Gene, RASAL2, is a Tumor and Metastasis Suppressor

PubMed Central

McLaughlin, Sara Koenig; Olsen, Sarah Naomi; Dake, Benjamin; De Raedt, Thomas; Lim, Elgene; Bronson, Roderick Terry; Beroukhim, Rameen; Polyak, Kornelia; Brown, Myles; Kuperwasser, Charlotte; Cichowski, Karen

2013-01-01

SUMMARY RAS genes are commonly mutated in cancer; however, RAS mutations are rare in breast cancer, despite the fact that Ras and ERK are frequently hyperactivated. Here we report that the RasGAP gene, RASAL2, functions as a tumor and metastasis suppressor. RASAL2 is mutated or suppressed in human breast cancer and RASAL2 ablation promotes tumor growth, progression, and metastasis in mouse models. In human breast cancer RASAL2-loss is associated with metastatic disease, low RASAL2 levels correlate with recurrence of luminal B tumors, and RASAL2 ablation promotes metastasis of luminal mouse tumors. Additional data reveal a broader role for RASAL2 inactivation in other tumor-types. These studies highlight the expanding role of RasGAPs and reveal an alternative mechanism of activating Ras in cancer. PMID:24029233

Do Rats Use Shape to Solve "Shape Discriminations"?

ERIC Educational Resources Information Center

Minini, Loredana; Jeffery, Kathryn J.

2006-01-01

Visual discrimination tasks are increasingly used to explore the neurobiology of vision in rodents, but it remains unclear how the animals solve these tasks: Do they process shapes holistically, or by using low-level features such as luminance and angle acuity? In the present study we found that when discriminating triangles from squares, rats did…

Human Newborn Color Vision: Measurement with Chromatic Stimuli Varying in Excitation Purity.

ERIC Educational Resources Information Center

Adams, Russell J.; Courage, Mary L.

1998-01-01

Habituated 180 neonates to white lights of varying luminance and tested for recovery of habituation to green, yellow, or red lights varying in excitation purity. Found that newborns discriminated chromatic stimuli from white only when excitation purity exceeded levels much higher than those for adults. Results reinforce view that neonates' vision…

Face and Object Discrimination in Autism, and Relationship to IQ and Age

ERIC Educational Resources Information Center

Pallett, Pamela M.; Cohen, Shereen J.; Dobkins, Karen R.

2014-01-01

The current study tested fine discrimination of upright and inverted faces and objects in adolescents with Autism Spectrum Disorder (ASD) as compared to age- and IQ-matched controls. Discrimination sensitivity was tested using morphed faces and morphed objects, and all stimuli were equated in low-level visual characteristics (luminance, contrast,…

Representation of time interval entrained by periodic stimuli in the visual thalamus of pigeons

PubMed Central

Wang, Shu-Rong

2017-01-01

Animals use the temporal information from previously experienced periodic events to instruct their future behaviors. The retina and cortex are involved in such behavior, but it remains largely unknown how the thalamus, transferring visual information from the retina to the cortex, processes the periodic temporal patterns. Here we report that the luminance cells in the nucleus dorsolateralis anterior thalami (DLA) of pigeons exhibited oscillatory activities in a temporal pattern identical to the rhythmic luminance changes of repetitive light/dark (LD) stimuli with durations in the seconds-to-minutes range. Particularly, after LD stimulation, the DLA cells retained the entrained oscillatory activities with an interval closely matching the duration of the LD cycle. Furthermore, the post-stimulus oscillatory activities of the DLA cells were sustained without feedback inputs from the pallium (equivalent to the mammalian cortex). Our study suggests that the experience-dependent representation of time interval in the brain might not be confined to the pallial/cortical level, but may occur as early as at the thalamic level. PMID:29284554

Glycosylphosphatidylinositol-anchored high density lipoprotein–binding protein 1 plays a critical role in the lipolytic processing of chylomicrons

PubMed Central

Beigneux, Anne P.; Davies, Brandon S. J.; Gin, Peter; Weinstein, Michael M.; Farber, Emily; Qiao, Xin; Peale, Franklin; Bunting, Stuart; Walzem, Rosemary L.; Wong, Jinny S.; Blaner, William S.; Ding, Zhi-Ming; Melford, Kristan; Wongsiriroj, Nuttaporn; Shu, Xiao; de Sauvage, Fred; Ryan, Robert O.; Fong, Loren G.; Bensadoun, André; Young, Stephen G.

2007-01-01

Summary The triglycerides in chylomicrons are hydrolyzed by lipoprotein lipase (LpL) along the luminal surface of the capillaries. However, the endothelial cell molecule that facilitates chylomicron processing by LpL has not yet been defined. Here, we show that glycosylphosphatidylinositol-anchored high density lipoprotein–binding protein 1 (GPIHBP1) plays a critical role in the lipolytic processing of chylomicrons. Gpihbp1-deficient mice exhibit a striking accumulation of chylomicrons in the plasma, even on a low-fat diet, resulting in milky plasma and plasma triglyceride levels as high as 5,000 mg/dl. Normally, Gpihbp1 is expressed highly in heart and adipose tissue, the same tissues that express high levels of LpL. In these tissues, GPIHBP1 is located on the luminal face of the capillary endothelium. Expression of GPIHBP1 in cultured cells confers the ability to bind both LpL and chylomicrons. These studies strongly suggest that GPIHBP1 is an important platform for the LpL-mediated processing of chylomicrons in capillaries. PMID:17403372

The Development of Luminance- and Texture-Defined Form Perception during the School-Aged Years

ERIC Educational Resources Information Center

Bertone, Armando; Hanck, Julie; Guy, Jacalyn; Cornish, Kim

2010-01-01

The objective of the present study was to assess the development of luminance- and texture-defined static form perception in school-aged children. This was done using an adapted Landolt-C technique where C-optotypes were defined by either luminance or texture information, the latter necessitating extra-striate neural processing to be perceived.…

A detail-preserved and luminance-consistent multi-exposure image fusion algorithm

NASA Astrophysics Data System (ADS)

Wang, Guanquan; Zhou, Yue

2018-04-01

When irradiance across a scene varies greatly, we can hardly get an image of the scene without over- or underexposure area, because of the constraints of cameras. Multi-exposure image fusion (MEF) is an effective method to deal with this problem by fusing multi-exposure images of a static scene. A novel MEF method is described in this paper. In the proposed algorithm, coarser-scale luminance consistency is preserved by contribution adjustment using the luminance information between blocks; detail-preserved smoothing filter can stitch blocks smoothly without losing details. Experiment results show that the proposed method performs well in preserving luminance consistency and details.

Association of proteasomal activity with metastasis in luminal breast cancer

NASA Astrophysics Data System (ADS)

Shashova, E. E.; Fesik, E. A.; Doroshenko, A. V.

2017-09-01

Chimotrypsin-like (ChTL) and caspase-like (CL) proteasomal activities were investigated in different variants of the tumor progression of luminal breast cancer. Patients with primary luminal breast cancer (n = 123) in stage T1-3N0-2M0 who had not received neoadjuvant treatment were included in this study. Proteasome ChTL and CL activities were determined in the samples of tumor and adjacent tissues. The coefficients of chymotrypsin-like (kChTL) and caspase-like (kCL) proteasome activity were also calculated as the ratio of the corresponding activity in the tumor tissue to activity in the adjacent tissue. ChTL, CL, kChTL and kCL in the tissues of luminal A and B breast cancer with lymphogenic metastasis were compared, and their association with hematogenous metastasis was evaluated. On the one hand, CL activity of proteasomes increased in luminal A breast cancer with extensive lymphogenic metastasis (N2), on the other hand it decreased in the luminal B subtype of cancer. The ratio of proteasomal activity in the tumor and adjacent tissues plays a significant role in the hematogenic pathway of breast cancer progression and is associated with poor metastatic-free survival.

Very Long O-antigen Chains Enhance Fitness during Salmonella-induced Colitis by Increasing Bile Resistance

PubMed Central

Crawford, Robert W.; Keestra, A. Marijke; Winter, Sebastian E.; Xavier, Mariana N.; Tsolis, Renée M.; Tolstikov, Vladimir; Bäumler, Andreas J.

2012-01-01

Intestinal inflammation changes the luminal habitat for microbes through mechanisms that have not been fully resolved. We noticed that the FepE regulator of very long O-antigen chain assembly in the enteric pathogen Salmonella enterica serotype Typhimurium (S. Typhimurium) conferred a luminal fitness advantage in the mouse colitis model. However, a fepE mutant was not defective for survival in tissue, resistance to complement or resistance to polymyxin B. We performed metabolite profiling to identify changes in the luminal habitat that accompany S. Typhimurium-induced colitis. This analysis suggested that S. Typhimurium-induced colitis increased the luminal concentrations of total bile acids. A mutation in fepE significantly reduced the minimal inhibitory concentration (MIC) of S. Typhimurium for bile acids in vitro. Oral administration of the bile acid sequestrant cholestyramine resin lowered the concentrations of total bile acids in colon contents during S. Typhimurium infection and significantly reduced the luminal fitness advantage conferred by the fepE gene in the mouse colitis model. Collectively, these data suggested that very long O-antigen chains function in bile acid resistance of S. Typhimurium, a property conferring a fitness advantage during luminal growth in the inflamed intestine. PMID:23028318

Symbiotic association of Photobacterium fischeri with the marine luminous fish Monocentris japonica; a model of symbiosis based on bacterial studies.

PubMed

Ruby, E G; Nealson, K H

1976-12-01

Isolation of bacteria from the luminous organ of the fish Monocentris japonica has revealed that the organ contains a pure culture of luminous bacteria. For the four fish examined, all contained Photobacterium fischeri as their luminous bacterial symbiont. This is the first time that P. fischeri has been identified in a symbiotic association. A representative isolate (MJl) of the light organ population was selected for in vivo studies of its luminous system. Several physiological features suggest adaptation for symbiotic existence. First, MJl has been shown to produce and respond to an inducer of luciferase that could accumulate in the light organ. Secondly, the specific activity of light production was seen to be maximal under low, growth-limiting concentrations of oxygen. Thirdly, unlike another luminous species (Beneckea harveyi), synthesis of the light production system of these bacteria is not catabolite repressed by glucose--a possible source of nutrition in the light organ. Fourthly, when grown aerobically on glucose these bacteria excrete pyruvic acid into the medium. This production of pyruvate is a major process, accounting for 30-40% of the glucose utilized and may serve as a form of regulatory and nutritional communication with the host.

Nature versus Nurture: Luminous Blue Variable Nebulae in and near Massive Stellar Clusters at the Galactic Center

NASA Astrophysics Data System (ADS)

Lau, R. M.; Herter, T. L.; Morris, M. R.; Adams, J. D.

2014-04-01

Three luminous blue variables (LBVs) are located in and near the Quintuplet Cluster at the Galactic center: the Pistol Star, G0.120-0.048, and qF362. We present imaging at 19, 25, 31, and 37 μm of the region containing these three LBVs, obtained with SOFIA using FORCAST. We argue that Pistol and G0.120-0.048 are identical "twins" that exhibit contrasting nebulae due to the external influence of their different environments. Our images reveal the asymmetric, compressed shell of hot dust surrounding the Pistol Star and provide the first detection of the thermal emission from the symmetric, hot dust envelope surrounding G0.120-0.048. However, no detection of hot dust associated with qF362 is made. Dust and gas composing the Pistol nebula are primarily heated and ionized by the nearby Quintuplet Cluster stars. The northern region of the Pistol nebula is decelerated due to the interaction with the high-velocity (2000 km s-1) winds from adjacent Wolf-Rayet Carbon (WC) stars. From fits to the spectral energy distribution (SED) of the Pistol nebula with the DustEM code we determine that the Pistol nebula is composed of a distribution of very small, transiently heated grains (10 to ~ 35 Å) having a total dust mass of 0.03 M ⊙, and that it exhibits a gradient of decreasing grain size from south to north due to differential sputtering by the winds from the WC stars. The total IR luminosity of the Pistol nebula is 5.2 × 105 L ⊙. Dust in the G0.120-0.048 nebula is primarily heated by the central star; however, the nebular gas is ionized externally by the Arches Cluster. Unlike the Pistol nebula, the G0.120-0.048 nebula is freely expanding into the surrounding medium. A grain size distribution identical to that of the non-sputtered region of the Pistol nebula satisfies the constraints placed on the G0.120-0.048 nebula from DustEM model fits to its SED and implies a total dust mass of 0.021 M ⊙. The total IR luminosity of the G0.120-0.048 nebula is ~105 L ⊙. From Paschen-α and 6 cm observations we determine a total gas mass of 9.3 M ⊙ and 6.2 M ⊙ for the Pistol and G0.120-0.048 nebulae, respectively. Given the independent dust and gas mass estimates we find that the Pistol and G0.120-0.048 nebulae exhibit similar gas-to-dust mass ratios of 310^{+77}_{-52} and 293^{+73}_{-101}, respectively. Both nebulae share identical size scales (~0.7 pc) which suggests that they have similar dynamical timescales of ~104 yr, assuming a shell expansion velocity of v exp = 60 km s-1.

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

PubMed

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

2017-07-01

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

Detection of chromatic and luminance distortions in natural scenes.

PubMed

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

2015-09-01

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

Resolution acuity versus recognition acuity with Landolt-style optotypes.

PubMed

Heinrich, Sven P; Bach, Michael

2013-09-01

International standards define acuity as the reciprocal of the threshold gap size of a Landolt C optotype. However, the literature is inconsistent as to what type of acuity is measured with Landolt Cs. The present study addresses this question more directly than previous studies by quantifying the effect of an inherent luminance artifact in Landolt-style optotypes. Two groups of modified optotypes were used. In the first group, each optotype had a single gap structure with the same average luminance. Between optotypes, the gap structures differed in their degree of fineness. In the second group of optotypes, a standard gap was always present, defining the orientation of the optotype. Additional gap structures of the same average luminance, but different fineness, were inserted at the remaining potential gap locations, thereby balancing luminance across potential gap locations. Visual acuity measures were obtained for each optotype variant, using a computer-based test employing a staircase procedure. Similar acuity values were obtained for all optotypes of the first group, and for standard Landolt Cs, irrespective of the fineness of the gap structure. With luminance-balanced optotypes of the second group, measured acuity was halved, compared to standard optotypes. The results support the view that it is recognition acuity, rather than resolution acuity, which is measured with standard Landolt-style optotypes, with the imbalanced luminance distribution serving as a cue. Luminance-balanced optotypes may help to obtain a more veridical estimate of resolution acuity, although recognition acuity may be more relevant in daily living.

On the search for an appropriate metric for reaction time to suprathreshold increments and decrements.

PubMed

Vassilev, Angel; Murzac, Adrian; Zlatkova, Margarita B; Anderson, Roger S

2009-03-01

Weber contrast, DeltaL/L, is a widely used contrast metric for aperiodic stimuli. Zele, Cao & Pokorny [Zele, A. J., Cao, D., & Pokorny, J. (2007). Threshold units: A correct metric for reaction time? Vision Research, 47, 608-611] found that neither Weber contrast nor its transform to detection-threshold units equates human reaction times in response to luminance increments and decrements under selective rod stimulation. Here we show that their rod reaction times are equated when plotted against the spatial luminance ratio between the stimulus and its background (L(max)/L(min), the larger and smaller of background and stimulus luminances). Similarly, reaction times to parafoveal S-cone selective increments and decrements from our previous studies [Murzac, A. (2004). A comparative study of the temporal characteristics of processing of S-cone incremental and decremental signals. PhD thesis, New Bulgarian University, Sofia, Murzac, A., & Vassilev, A. (2004). Reaction time to S-cone increments and decrements. In: 7th European conference on visual perception, Budapest, August 22-26. Perception, 33, 180 (Abstract).], are better described by the spatial luminance ratio than by Weber contrast. We assume that the type of stimulus detection by temporal (successive) luminance discrimination, by spatial (simultaneous) luminance discrimination or by both [Sperling, G., & Sondhi, M. M. (1968). Model for visual luminance discrimination and flicker detection. Journal of the Optical Society of America, 58, 1133-1145.] determines the appropriateness of one or other contrast metric for reaction time.

Effect of stimulus size and luminance on the rod-, cone-, and melanopsin-mediated pupillary light reflex

PubMed Central

Park, Jason C.; McAnany, J. Jason

2015-01-01

This study determined if the pupillary light reflex (PLR) driven by brief stimulus presentations can be accounted for by the product of stimulus luminance and area (i.e., corneal flux density, CFD) under conditions biased toward the rod, cone, and melanopsin pathways. Five visually normal subjects participated in the study. Stimuli consisted of 1-s short- and long-wavelength flashes that spanned a large range of luminance and angular subtense. The stimuli were presented in the central visual field in the dark (rod and melanopsin conditions) and against a rod-suppressing short-wavelength background (cone condition). Rod- and cone-mediated PLRs were measured at the maximum constriction after stimulus onset whereas the melanopsin-mediated PLR was measured 5–7 s after stimulus offset. The rod- and melanopsin-mediated PLRs were well accounted for by CFD, such that doubling the stimulus luminance had the same effect on the PLR as doubling the stimulus area. Melanopsin-mediated PLRs were elicited only by short-wavelength, large (>16°) stimuli with luminance greater than 10 cd/m2, but when present, the melanopsin-mediated PLR was well accounted for by CFD. In contrast, CFD could not account for the cone-mediated PLR because the PLR was approximately independent of stimulus size but strongly dependent on stimulus luminance. These findings highlight important differences in how stimulus luminance and size combine to govern the PLR elicited by brief flashes under rod-, cone-, and melanopsin-mediated conditions. PMID:25788707

Evaluation of potential substrates for restenosis and thrombosis in overlapped versus edge-to-edge juxtaposed bioabsorbable scaffolds: Insights from a computed fluid dynamic study.

PubMed

Rigatelli, Gianluca; Zuin, Marco; Dell'Avvocata, Fabio; Cardaioli, Paolo; Vassiliev, Dobrin; Ferenc, Miroslaw; Nghia, Nguyen Tuan; Nguyen, Thach; Foin, Nicholas

2018-04-01

Multiple BRSs and specifically the Absorb scaffold (BVS) (Abbott Vascular, Santa Clara, CA USA) have been often used to treat long diffuse coronary artery lesions. We evaluate by a computational fluid dynamic(CFD) study the impact on the intravascular fluid rheology on multiple bioabsorbable scaffolds (BRS) by standard overlapping versus edge-to-edge technique. We simulated the treatment of a real long significant coronary lesion (>70% luminal narrowing) involving the left anterior descending artery (LAD) treated with a standard or edge-to-edge technique, respectively. Simulations were performed after BVS implantations in two different conditions: 1) Edge-to-edge technique, where the scaffolds are kissed but not overlapped resulting in a luminal encroachment of 0.015cm (150μm); 2) Standard overlapping, where the scaffolds are overlapped resulting in a luminal encroachment of 0.030cm (300μm). After positioning the BVS across the long lesion, the implantation procedure was performed in-silico following all the usual procedural steps. Analysis of the wall shear stress (WSS) suggested that at the vessel wall level the WSS were lower in the overlapping zones overlapping compared to the edge-to-edge zone (∆=0.061Pa, p=0.01). At the struts level the difference between the two WSS was more striking (∆=1.065e-004 p=0.01) favouring the edge-to-edge zone. Our study suggested that at both vessel wall and scaffold struts levels, there was lowering WSS when multiple BVS were implanted with the standard overlapping technique compared to the "edge-to-edge" technique. This lower WSS might represent a substrate for restenosis, early and late BVS thrombosis, potentially explaining at least in part the recent evidences of devices poor performance. Copyright © 2017 Elsevier Inc. All rights reserved.

Hubble Space Telescope Images of Nearby Luminous Quasars. 2; Results for Eight Quasars and Tests of the Detection Sensitivity

NASA Technical Reports Server (NTRS)

Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.

1995-01-01

Observations with the Wide-Field Camera of the Hubble Space Telescope (HST) are presented for eight intrinsically luminous quasars with redshifts between 0.16 and 0.29. These observations, when combined with a similar HST study of the quasar PKS 2349-014, show that luminous nearby quasars exist in a variety of environments. Seven companion galaxies brighter than M(V) = 16.5 (H(sub 0) = 100 km s(sup -1) Mpc(sup -1), Omega(sub 0) = 1.0) lie within a projected distance of 25 kpc of the quasars; three of the companions are located closer than 3'' (6 kpc projected distance) from the quasars, well within the volume that would be enclosed by a typical L* host galaxy. The observed association of quasars and companion galaxies is statistically significant and may he an important element in the luminous-quasar phenomenon. Apparent host galaxies are detected for three of the quasars: PG 1116+215, 3C 273, and PG 1444+407; the hosts have an average absolute magnitude of about 0.6 mag brighter than L*. The agreement between the previously published major-axis directions in ground-based images and in the present HST images of 3C 273 and PG 1444+407 constitutes important evidence supporting the reality of these candidate host galaxies. Upper limits are placed on the visual-band brightnesses of representative galactic hosts for all the quasars. These limits are established by placing galaxy images obtained with HST underneath the quasars and measuring at what faintness level the known galaxies are detected. On average, the HST spirals would have been detected if they were as faint as 1 mag below L*, and the early-type galaxies could have been detected down to a brightness level of about L*, where L* is the Schechter characteristic luminosity of field galaxies. Smooth, featureless galaxy models (exponential disks or de Vaucouleurs profiles) are fitted to the residual light after a best-fitting point source is subtracted from the quasar images. The results show that smooth spiral galaxies brighter than, on average, about L*, would have been detected. These upper limits, or possible detections, are consistent with, for example, the eight luminous quasars studied in this paper, occurring in host galaxies that have a Shechter luminosity function with a lower cutoff in the range 0.01-0.1 L*. Tests are performed to determine if our failure to detect, in some cases, luminous host galaxies could be an artifact caused by our analysis procedures. These tests include comparing the measured point-spread function (PSF) for our HST observations with the PSFs used in previous ground-based studies of host galaxies, measuring the fluctuations in the sky signals that were subtracted from the quasar images, evaluating empirically the effects of using different stellar PSFs in the analysis, carrying out the subtraction of the stellar (nuclear) source in different ways, creating and analyzing artificial active galactic nuclei (AGNs) with known surface brightnesses, and fitting the observed quasar light to an analytic model that includes a host galaxy.

Association of CA 15-3 and CEA with clinicopathological parameters in patients with metastatic breast cancer.

PubMed

Geng, Biao; Liang, Man-Man; Ye, Xiao-Bing; Zhao, Wen-Ying

2015-01-01

The objective of this study was to investigate the association of serum cancer antigen 15-3 (CA 15-3) and carcinoembryonic antigen (CEA) levels with clinicopathological parameters in patients diagnosed with metastatic breast cancer (MBC). We retrospectively evaluated the medical records of 284 patients diagnosed with MBC between January, 2007 and December, 2012 who fulfilled the specified criteria and the association between the levels of the two tumor marker and clinicopathological parameters was analyzed. Of the 284 patients, elevated CA 15-3 and CEA levels at initial diagnosis of recurrence were identified in 163 (57.4%) and 97 (34.2%) patients, respectively. Elevated CA 15-3 and CEA levels were significantly associated with breast cancer molecular subtypes (P<0.001 and P=0.032, respectively). Cases with luminal subtypes exhibited a higher percentage of elevated CA 15-3 and CEA levels compared to non-luminal subtypes. Elevated CA 15-3 level was correlated with bone metastasis (P=0.017). However, elevation of CEA was observed regardless of the site of metastasis. Elevation of CA 15-3 was significantly more common in MBC with multiple metastatic sites compared to MBC with a single metastasis (P=0.001). However, the incidence of elevated CEA levels did not differ between patients with a single and those with multiple metastatic sites. In conclusion, elevated CA 15-3 and CEA levels at initial diagnosis of recurrence were found to be associated with breast cancer molecular subtypes, whereas an elevated CA 15-3 level was significantly correlated with bone metastasis and an elevated CEA level was observed regardless of metastatic site. The proportion of MBC cases with elevated CA 15-3 levels differed according to the number of metastatic sites.

Eta Carinae and Other Luminous Blue Variables

NASA Technical Reports Server (NTRS)

Corcoran, M. F.

2006-01-01

Luminous Blue Variables (LBVs) are believed to be evolved, extremely massive stars close to the Eddington Limit and hence prone to bouts of large-scale, unstable mass loss. I discuss current understanding of the evolutionary state of these objects, the role duplicity may play and known physical characteristics of these stars using the X-ray luminous LBVs Eta Carinae and HD 5980 as test cases.

Learning to identify contrast-defined letters in peripheral vision

PubMed Central

Chung, Susana T.L.; Levi, Dennis M.; Li, Roger W.

2009-01-01

Performance for identifying luminance-defined letters in peripheral vision improves with training. The purpose of the present study was to examine whether performance for identifying contrast-defined letters also improves with training in peripheral vision, and whether any improvement transfers to luminance-defined letters. Eight observers were trained to identify contrast-defined letters presented singly at 10° eccentricity in the inferior visual field. Before and after training, we measured observers’ thresholds for identifying luminance-defined and contrast-defined letters, embedded within a field of white luminance noise (maximum luminance contrast = 0, 0.25, and 0.5), at the same eccentric location. Each training session consisted of 10 blocks (100 trials per block) of identifying contrast-defined letters at a background noise contrast of 0.5. Letters (x-height = 4.2°) were the 26 lowercase letters of the Times-Roman alphabet. Luminance-defined letters were generated by introducing a luminance difference between the stimulus letter and its mid-gray background. The background noise covered both the letter and its background. Contrast-defined letters were generated by introducing a differential noise contrast between the group of pixels that made up the stimulus letter and the group of pixels that made up the background. Following training, observers showed a significant reduction in threshold for identifying contrast-defined letters (p < 0.0001). Averaged across observers and background noise contrasts, the reduction was 25.8%, with the greatest reduction (32%) occurring at the trained background noise contrast. There was virtually no transfer of improvement to luminance-defined letters, or to an untrained letter size (2× original), or an untrained retinal location (10° superior field). In contrast, learning transferred completely to the untrained contralateral eye. Our results show that training improves performance for identifying contrast-defined letters in peripheral vision. This perceptual learning effect seems to be stimulus-specific, as it shows no transfer to the identification of luminance-defined letters. The complete interocular transfer, and the retinotopic (retinal location) and size specificity of the learning effect are consistent with the properties of neurons in early visual area V2. PMID:16337252

ROSAT HRI and ASCA Observations of the Spiral Galaxy NGC 6946 and its Northeast Complex of Luminous Supernova Remnants

NASA Technical Reports Server (NTRS)

Schlegel, E.; Swank, Jean (Technical Monitor)

2001-01-01

Analysis of 80 ks ASCA (Advanced Satellite for Cosmology and Astrophysics) and 60 ks ROSAT HRI (High Resolution Image) observations of the face-on spiral galaxy NGC 6946 are presented. The ASCA image is the first observation of this galaxy above approximately 2 keV. Diffuse emission may be present in the inner approximately 4' extending to energies above approximately 2-3 keV. In the HRI data, 14 pointlike sources are detected, the brightest two being a source very close to the nucleus and a source to the northeast that corresponds to a luminous complex of interacting supernova remnants (SNRs). We detect a point source that lies approximately 30" west of the SNR complex but with a luminosity -1115 of the SNR complex. None of the point sources show evidence of strong variability; weak variability would escape our detection. The ASCA spectrum of the SNR complex shows evidence for an emission line at approximately 0.9 keV that could be either Ne IX at approximately 0.915 keV or a blend of ion stages of Fe L-shell emission if the continuum is fitted with a power law. However, a two-component, Raymond-Smith thermal spectrum with no lines gives an equally valid continuum fit and may be more physically plausible given the observed spectrum below 3 keV. Adopting this latter model, we derive a density for the SNR complex of 10-35 cm(exp -3), consistent with estimates inferred from optical emission-line ratios. The complex's extraordinary X-ray luminosity may be related more to the high density of the surrounding medium than to a small but intense interaction region where two of the complex's SNRs are apparently colliding.

A COMPARATIVE STUDY OF KNOTS OF STAR FORMATION IN INTERACTING VERSUS SPIRAL GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Beverly J.; Olmsted, Susan; Jones, Keith

2016-03-15

Interacting galaxies are known to have higher global rates of star formation on average than normal galaxies, relative to their stellar masses. Using UV and IR photometry combined with new and published Hα images, we have compared the star formation rates (SFRs) of ∼700 star forming complexes in 46 nearby interacting galaxy pairs with those of regions in 39 normal spiral galaxies. The interacting galaxies have proportionally more regions with high SFRs than the spirals. The most extreme regions in the interacting systems lie at the intersections of spiral/tidal structures, where gas is expected to pile up and trigger starmore » formation. Published Hubble Space Telescope images show unusually large and luminous star clusters in the highest luminosity regions. The SFRs of the clumps correlate with measures of the dust attenuation, consistent with the idea that regions with more interstellar gas have more star formation. For the clumps with the highest SFRs, the apparent dust attenuation is consistent with the Calzetti starburst dust attenuation law. This suggests that the high luminosity regions are dominated by a central group of young stars surrounded by a shell of clumpy interstellar gas. In contrast, the lower luminosity clumps are bright in the UV relative to Hα, suggesting either a high differential attenuation between the ionized gas and the stars, or a post-starburst population bright in the UV but faded in Hα. The fraction of the global light of the galaxies in the clumps is higher on average for the interacting galaxies than for the spirals. Thus either star formation in interacting galaxies is “clumpier” on average, or the star forming regions in interacting galaxies are more luminous, dustier, or younger on average.« less

A SAMPLE OF SEYFERT-2 GALAXIES WITH ULTRALUMINOUS GALAXY-WIDE NARROW-LINE REGIONS: QUASAR LIGHT ECHOES?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schirmer, M.; Diaz, R.; Levenson, N. A.

2013-01-20

We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide, ultraluminous narrow-line regions (NLRs) at redshifts z = 0.2-0.6. With a space density of 4.4 Gpc{sup -3} at z {approx} 0.3, these 'green beans' (GBs) are amongst the rarest objects in the universe. We are witnessing an exceptional and/or short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). The main focus of this paper is on a detailed analysis of the GB prototype galaxy J2240-0927 (z = 0.326). Its NLR extends over 26 Multiplication-Sign 44 kpc and is surrounded by an extended NLR. With a total [Omore » III] {lambda}5008 luminosity of (5.7 {+-} 0.9) Multiplication-Sign 10{sup 43} erg s{sup -1}, this is one of the most luminous NLRs known around any type-2 galaxy. Using VLT/XSHOOTER, we show that the NLR is powered by an AGN, and we derive resolved extinction, density, and ionization maps. Gas kinematics is disturbed on a global scale, and high-velocity outflows are absent or faint. This NLR is unlike any other NLR or extended emission line region known. Spectroscopy with Gemini/GMOS reveals extended, high-luminosity [O III] emission also in other GBs. WISE 24 {mu}m luminosities are 5-50 times lower than predicted by the [O III] fluxes, suggesting that the NLRs reflect earlier, very active quasar states that have strongly subsided in less than a galaxy's light-crossing time. These light echoes, or ionization echoes, are about 100 times more luminous than any other such echo known to date. X-ray data are needed for photoionization modeling and to verify the light echoes.« less

Geometry and physical conditions in the stellar wind of AG Carinae

NASA Technical Reports Server (NTRS)

Leitherer, Claus; Allen, Richard; Altner, Bruce; Damineli, Augusto; Drissen, Laurent; Idiart, Thais; Lupie, Olivia; Nota, Antonella; Robert, Carmelle; Schmutz, Werner

1994-01-01

AG Carinae is one of the prototypes of the class of Luminous Blue Variables (LBVs). Since 1990 the star has continuously brightened in its visual continuum. We report on a multi-instrument and -wavelength observing campaign to monitor the current activity phase of AG Car. Ground-based photometry, polarimetry, spectroscopy, and space-ultraviolet spectroscopy and spectropolarimetry have been obtained. From the variability of the polarization at ultraviolet and optical wavelengths we detect significant intrinsic polarization. P(sub int) greater than or equal to 0.5% is a large value for a hot, luminous star, suggesting departure from spherical symmetry in the wind of AG Car. The intrinsic polarization is variable on a timescale of 2 months or less. The measured ultraviolet polarization (intrinsic + interstellar) dropped to 0.5% in 1992 May and returned to 1% in 1992 July. The results are interpreted in terms of a variable outflow with a density enhancement in the equatorial plane. A similar model was suggested for the related object R127 in the Large Magellanic Cloud (LMC). This geometry is reminiscent of the large-scale morphology of the gas nebula and dust 'jet' surrounding AG Car. It is therefore likely that physical conditions close to the stellar surface are responsible for the geometry of the spatially resolved circumstellar material around AG Car. Despite the drastic change of the photospheric conditions, the mass-loss rate did not increase. We find no evidence for a positive correlation between wind density and stellar radius. This makes models that explain the radius increase by opacity effects in the outflow unlikely. The mechanism responsible for the temperature and radius variations is still unknown but most likely has its origin in subphotospheric regions.

Sry HMG Box Protein 9-positive (Sox9+) Epithelial Cell Adhesion Molecule-negative (EpCAM−) Biphenotypic Cells Derived from Hepatocytes Are Involved in Mouse Liver Regeneration*

PubMed Central

Tanimizu, Naoki; Nishikawa, Yuji; Ichinohe, Norihisa; Akiyama, Haruhiko; Mitaka, Toshihiro

2014-01-01

It has been shown that mature hepatocytes compensate tissue damages not only by proliferation and/or hypertrophy but also by conversion into cholangiocyte-like cells. We found that Sry HMG box protein 9-positive (Sox9+) epithelial cell adhesion molecule-negative (EpCAM−) hepatocyte nuclear factor 4α-positive (HNF4α+) biphenotypic cells showing hepatocytic morphology appeared near EpCAM+ ductular structures in the livers of mice fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing diet. When Mx1-Cre:ROSA mice, which were injected with poly(I:C) to label mature hepatocytes, were fed with the DDC diet, we found LacZ+Sox9+ cells near ductular structures. Although Sox9+EpCAM− cells adjacent to expanding ducts likely further converted into ductular cells, the incidence was rare. To know the cellular characteristics of Sox9+EpCAM− cells, we isolated them as GFP+EpCAM− cells from DDC-injured livers of Sox9-EGFP mice. Sox9+EpCAM− cells proliferated and could differentiate to functional hepatocytes in vitro. In addition, Sox9+EpCAM− cells formed cysts with a small central lumen in collagen gels containing Matrigel® without expressing EpCAM. These results suggest that Sox9+EpCAM− cells maintaining biphenotypic status can establish cholangiocyte-type polarity. Interestingly, we found that some of the Sox9+ cells surrounded luminal spaces in DDC-injured liver while they expressed HNF4α. Taken together, we consider that in addition to converting to cholangiocyte-like cells, Sox9+EpCAM− cells provide luminal space near expanded ductular structures to prevent deterioration of the injuries and potentially supply new hepatocytes to repair damaged tissues. PMID:24482234

Why Rudolph’s nose is red: observational study

PubMed Central

van Kuijen, Anne-Marije; Milstein, Dan M J; Yürük, Koray; Folkow, Lars P; Fokkens, Wytske J; Blix, Arnoldus S

2012-01-01

Objective To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus’s sleigh, is due to the presence of a highly dense and rich nasal microcirculation. Design Observational study. Setting Tromsø, Norway (near the North Pole), and Amsterdam, the Netherlands. Participants Five healthy human volunteers, two adult reindeer, and a patient with grade 3 nasal polyposis. Main outcome measures Architecture of the microvasculature of the nasal septal mucosa and head of the inferior turbinates, kinetics of red blood cells, and real time reactivity of the microcirculation to topical medicines. Results Similarities between human and reindeer nasal microcirculation were uncovered. Hairpin-like capillaries in the reindeers’ nasal septal mucosa were rich in red blood cells, with a perfused vessel density of 20 (SD 0.7) mm/mm2. Scattered crypt or gland-like structures surrounded by capillaries containing flowing red blood cells were found in human and reindeer noses. In a healthy volunteer, nasal microvascular reactivity was demonstrated by the application of a local anaesthetic with vasoconstrictor activity, which resulted in direct cessation of capillary blood flow. Abnormal microvasculature was observed in the patient with nasal polyposis. Conclusions The nasal microcirculation of reindeer is richly vascularised, with a vascular density 25% higher than that in humans. These results highlight the intrinsic physiological properties of Rudolph’s legendary luminous red nose, which help to protect it from freezing during sleigh rides and to regulate the temperature of the reindeer’s brain, factors essential for flying reindeer pulling Santa Claus’s sleigh under extreme temperatures. PMID:23247980

Three-dimensional cell shapes and arrangements in human sweat glands as revealed by whole-mount immunostaining

PubMed Central

Kurata, Ryuichiro; Futaki, Sugiko; Nakano, Itsuko; Fujita, Fumitaka; Tanemura, Atsushi; Murota, Hiroyuki; Katayama, Ichiro; Okada, Fumihiro

2017-01-01

Because sweat secretion is facilitated by mechanical contraction of sweat gland structures, understanding their structure-function relationship could lead to more effective treatments for patients with sweat gland disorders such as heat stroke. Conventional histological studies have shown that sweat glands are three-dimensionally coiled tubular structures consisting of ducts and secretory portions, although their detailed structural anatomy remains unclear. To better understand the details of the three-dimensional (3D) coiled structures of sweat glands, a whole-mount staining method was employed to visualize 3D coiled gland structures with sweat gland markers for ductal luminal, ductal basal, secretory luminal, and myoepithelial cells. Imaging the 3D coiled gland structures demonstrated that the ducts and secretory portions were comprised of distinct tubular structures. Ductal tubules were occasionally bent, while secretory tubules were frequently bent and formed a self-entangled coiled structure. Whole-mount staining of complex coiled gland structures also revealed the detailed 3D cellular arrangements in the individual sweat gland compartments. Ducts were composed of regularly arranged cuboidal shaped cells, while secretory portions were surrounded by myoepithelial cells longitudinally elongated along entangled secretory tubules. Whole-mount staining was also used to visualize the spatial arrangement of blood vessels and nerve fibers, both of which facilitate sweat secretion. The blood vessels ran longitudinally parallel to the sweat gland tubules, while nerve fibers wrapped around secretory tubules, but not ductal tubules. Taken together, whole-mount staining of sweat glands revealed the 3D cell shapes and arrangements of complex coiled gland structures and provides insights into the mechanical contraction of coiled gland structures during sweat secretion. PMID:28636607

The Tadpole and the Wriggler

NASA Image and Video Library

2014-04-14

A bright blue tadpole appears to swim through the inky blackness of space. Known as IRAS 20324+4057, but dubbed "the Tadpole," this clump of gas and dust has given birth to a bright, "protostar," one of the earliest steps in building a star. This image was taken by NASA's Hubble Space Telescope, and released publicly, in 2012. There are actually multiple protostars within this tadpole's 'head," but the glowing yellow one in this image is the most luminous and massive. When this protostar has gathered together enough mass from its surroundings, it will eventually emerge as a fully-fledged young star. The intense blue glow is caused by nearby stars firing ultraviolet radiation at IRAS 20324+4057, which also sculpts its tail into a long, wiggly shape. In total, this clump spans roughly a light-year from head to tail-tip, and contains gas weighing almost four times the mass of the sun. Framed against a background of distant stars, IRAS 20324+4057 is making its way through the Cygnus OB2 association, a loose cluster of stars some 4,700 light-years from Earth in the constellation Cygnus. This association is one of the largest clusters known, and is famed for its heavyweight members. It contains some of the hottest, most massive and most luminous stars known, some of which are about two million times more luminous than the sun. The Tadpole is not alone in this interstellar pond. Just out of view, to the bottom right of this image, lies another curious object dubbed "the Goldfish" by astronomers. The Goldfish is about half the length of IRAS 20324+4057, and is also thought to be a globule of gas that is being both lit up and sculpted by radiation from cluster stars. Completing this trio is a small clump of blue gas, informally nicknamed "the Wriggler" by some astronomers, visible in the bottom left of this Hubble image. All three objects have the same orientation in the sky and appear to be brighter on their northern sides, leading astronomers to believe they are being shaped by aggressive winds and radiation flowing from hot Cygnus OB2 stars towards the top right of the frame. http://photojournal.jpl.nasa.gov/catalog/PIA18168

Rab25 acts as an oncogene in luminal B breast cancer and is causally associated with Snail driven EMT

PubMed Central

Mitra, Shreya; Federico, Lorenzo; Zhao, Wei; Dennison, Jennifer; Sarkar, Tapasree Roy; Zhang, Fan; Takiar, Vinita; Cheng, Kwai W.; Mani, Sendurai; Lee, Ju Seog; Mills, Gordon B.

2016-01-01

The Rab GTPases regulate vesicular trafficking machinery that transports and delivers a diverse pool of cargo, including growth factor receptors, integrins, nutrient receptors and junction proteins to specific intracellular sites. The trafficking machinery is indeed a major posttranslational modifier and is critical for cellular homeostasis. Deregulation of this stringently controlled system leads to a wide spectrum of disorders including cancer. Herein we demonstrate that Rab25, a key GTPase, mostly decorating the apical recycling endosome, is a dichotomous variable in breast cancer cell lines with higher mRNA and protein expression in Estrogen Receptor positive (ER+ve) lines. Rab25 and its effector, Rab Coupling Protein (RCP) are frequently coamplified and coordinately elevated in ER+ve breast cancers. In contrast, Rab25 levels are decreased in basal-like and almost completely lost in claudin-low tumors. This dichotomy exists despite the presence of the 1q amplicon that hosts Rab25 across breast cancer subtypes and is likely due to differential methylation of the Rab25 promoter. Functionally, elevated levels of Rab25 drive major hallmarks of cancer including indefinite growth and metastasis but in case of luminal B breast cancer only. Importantly, in such ER+ve tumors, coexpression of Rab25 and its effector, RCP is significantly associated with a markedly worsened clinical outcome. Importantly, in claudin-low cell lines, exogenous Rab25 markedly inhibits cell migration. Similarly, during Snail-induced epithelial to mesenchymal transition (EMT) exogenous Rab25 potently reverses Snail-driven invasion. Overall, this study substantiates a striking context dependent role of Rab25 in breast cancer where Rab25 is amplified and enhances aggressiveness in luminal B cancers while in claudin-low tumors, Rab25 is lost indicating possible anti-tumor functions. PMID:27259233

Rab25 acts as an oncogene in luminal B breast cancer and is causally associated with Snail driven EMT.

PubMed

Mitra, Shreya; Federico, Lorenzo; Zhao, Wei; Dennison, Jennifer; Sarkar, Tapasree Roy; Zhang, Fan; Takiar, Vinita; Cheng, Kwai W; Mani, Sendurai; Lee, Ju Seog; Mills, Gordon B

2016-06-28

The Rab GTPases regulate vesicular trafficking machinery that transports and delivers a diverse pool of cargo, including growth factor receptors, integrins, nutrient receptors and junction proteins to specific intracellular sites. The trafficking machinery is indeed a major posttranslational modifier and is critical for cellular homeostasis. Deregulation of this stringently controlled system leads to a wide spectrum of disorders including cancer. Herein we demonstrate that Rab25, a key GTPase, mostly decorating the apical recycling endosome, is a dichotomous variable in breast cancer cell lines with higher mRNA and protein expression in Estrogen Receptor positive (ER+ve) lines. Rab25 and its effector, Rab Coupling Protein (RCP) are frequently coamplified and coordinately elevated in ER+ve breast cancers. In contrast, Rab25 levels are decreased in basal-like and almost completely lost in claudin-low tumors. This dichotomy exists despite the presence of the 1q amplicon that hosts Rab25 across breast cancer subtypes and is likely due to differential methylation of the Rab25 promoter. Functionally, elevated levels of Rab25 drive major hallmarks of cancer including indefinite growth and metastasis but in case of luminal B breast cancer only. Importantly, in such ER+ve tumors, coexpression of Rab25 and its effector, RCP is significantly associated with a markedly worsened clinical outcome. Importantly, in claudin-low cell lines, exogenous Rab25 markedly inhibits cell migration. Similarly, during Snail-induced epithelial to mesenchymal transition (EMT) exogenous Rab25 potently reverses Snail-driven invasion. Overall, this study substantiates a striking context dependent role of Rab25 in breast cancer where Rab25 is amplified and enhances aggressiveness in luminal B cancers while in claudin-low tumors, Rab25 is lost indicating possible anti-tumor functions.

Lanthanum inhibition of Vibrio cholerae and Escherichia coli enterotoxin-induced enterosorption and its effects on intestinal mucosa cyclic adenosine 3',5'-monophosphate and cyclic guanosine 3',5'-monophosphate levels.

PubMed Central

Leitch, G J; Amer, M S

1975-01-01

Several trivalent cations, including lanthanum (La3+), inhibited the secretion (enterosorption) induced by the enterotoxins of Vibrio cholerae and Escherichia coli in the rabbit ileum in vivo. High concentrations (greater than 10 mM) of La3+ were required to inhibit cholera enterotoxin (CE)-induced enterosorption, probably because of the adsorption of the La3+ often potentiated the CE-induced enterosorption. If luminal La3+ exposure followed CE exposure, some recovery of the enterosorptive response was observed. The longer the lag between the CE exposure and the La3+ exposure, the greater was the recovery of the enterosorptive response. Lanthanum inhibited HCO3- secretion more than Cl- secretion. By altering the luminal fluid pH at the time of La3+ exposure, it was found that La3+ was adsorbed to negatively charged luminal sites, having an apparent pK between 2.5 and 3.0. Although La3+ antagonized the enterosorptive response to CE, it mimicked rather than antagonized the cyclic adenosine 3',5'-monophosphate elevation and cyclic guanosine 3',5'-monophosphate depression induced by the toxin. It is therefore concluded that the La3+ inhibition of the CE-induced enterosorption must have occurred at a site following the generation of the cyclic nucleotides. Cholera enterotoxin caused complex time-dependent changes in the mucosal cyclic adenosine 3',5'-monophosphate and cyclic guanosine 3',5'-monophosphate levels, as revealed by studying tissue cyclic adenosine 3',5'-monophosphate/cyclic guanosine 3',5'-monophosphate ratios. The possible roles these two cyclic nucleotides may play in the pathogenesis of the cholera diarrhea are discussed. PMID:164410

Evaluation of High Dynamic Range Photography as a Luminance Mapping Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inanici, Mehlika; Galvin, Jim

2004-12-30

The potential, limitations, and applicability of the High Dynamic Range (HDR) photography technique is evaluated as a luminance mapping tool. Multiple exposure photographs of static scenes are taken with a Nikon 5400 digital camera to capture the wide luminance variation within the scenes. The camera response function is computationally derived using the Photosphere software, and is used to fuse the multiple photographs into HDR images. The vignetting effect and point spread function of the camera and lens system is determined. Laboratory and field studies have shown that the pixel values in the HDR photographs can correspond to the physical quantitymore » of luminance with reasonable precision and repeatability.« less

Intraluminal laser speckle rheology using an omni-directional viewing catheter

PubMed Central

Wang, Jing; Hosoda, Masaki; Tshikudi, Diane M.; Hajjarian, Zeinab; Nadkarni, Seemantini K.

2016-01-01

A number of disease conditions in luminal organs are associated with alterations in tissue mechanical properties. Here, we report a new omni-directional viewing Laser Speckle Rheology (LSR) catheter for mapping the mechanical properties of luminal organs without the need for rotational motion. The LSR catheter incorporates multiple illumination fibers, an optical fiber bundle and a multi-faceted mirror to permit omni-directional viewing of the luminal wall. By retracting the catheter using a motor-drive assembly, cylindrical maps of tissue mechanical properties are reconstructed. Evaluation conducted in a test phantom with circumferentially-varying mechanical properties demonstrates the capability of the LSR catheter for the accurate mechanical assessment of luminal organs. PMID:28101407

Observations of Ultra-Luminous X-ray Sources, and Implications

NASA Astrophysics Data System (ADS)

Colbert, E. J. M.

2004-05-01

I will review observations of Ultra-Luminous X-ray Sources (ULXs; Lx > 1E39 erg/s), in particular those observations that have helped reveal the nature of these curious objects. Some recent observations suggest that ULXs are a heterogenous class. Although ULX phenomenology is not fully understood, I will present some examples from the (possibly overlapping) sub-classes. Since ULXs are the most luminous objects in starburst galaxies, they, and ``normal'' luminous black-hole high-mass X-ray binaries are intimately tied to the global galaxian X-ray-star-formation connection. Further work is needed to understand how ULXs form, and how they are associated with the putative population of intermediate-mass black holes.

Brightness perception of unrelated self-luminous colors.

PubMed

Withouck, Martijn; Smet, Kevin A G; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Koenderink, Jan; Hanselaer, Peter

2013-06-01

The perception of brightness of unrelated self-luminous colored stimuli of the same luminance has been investigated. The Helmholtz-Kohlrausch (H-K) effect, i.e., an increase in brightness perception due to an increase in saturation, is clearly observed. This brightness perception is compared with the calculated brightness according to six existing vision models, color appearance models, and models based on the concept of equivalent luminance. Although these models included the H-K effect and half of them were developed to work with unrelated colors, none of the models seemed to be able to fully predict the perceived brightness. A tentative solution to increase the prediction accuracy of the color appearance model CAM97u, developed by Hunt, is presented.

SLP-2 overexpression could serve as a prognostic factor in node positive and HER2 negative breast cancer.

PubMed

Cao, Wenfeng; Zhang, Bin; Li, Jin; Liu, Yanxue; Liu, Zhihua; Sun, Baocun

2011-12-01

This study aimed to evaluate the utility as a prognostic factor of SLP-2 on the outcome of breast cancer patients. We performed immunohistochemical analysis to examine the SLP-2 expression in a large panel of invasive breast cancer samples. Of the 496 samples, 261 showed overexpression of SLP-2. Importantly, there were significant associations between SLP-2 overexpression and tumour size (p = 0.002), lymph node/distant metastases, clinical stage (p < 0.001), HER2/neu expression (p = 0.003). In addition, there were obvious differences in levels of SLP-2 expression within four molecular subtypes of breast cancer (p = 0.011). High level SLP-2 expression was shown in tumour samples of HER2 and luminal B subtypes, and low level SLP-2 expression was shown in luminal A and triple negative subtypes, suggesting that overexpression of SLP-2 was closely correlated with HER2/neu expression, and that both SLP-2 and HER2/neu can play a role in lymph node/distant metastases of breast cancers. Thus lymph node status, HER2/neu and SLP-2 high-level expression can act as independent prognostic factors. There is an obvious link between SLP-2 and HER2/neu expression. Overexpression of SLP-2 is associated with poorer total survival, especially in lymph node positive coupled with HER2/neu negative patients.

Simulation of a central scotoma using contact lenses with an opaque centre.

PubMed

Almutleb, Essam S; Bradley, Arthur; Jedlicka, Jason; Hassan, Shirin E

2018-01-01

This study evaluated the feasibility of using soft contact lenses (CLs) with an opaque centre to induce absolute central scotomas that move with the eye. We examined the geometrical optics prediction that scotoma size will vary with the size of the CL's opaque centre and with ocular pupil size. We also tested the hypothesis that high environmental light levels will ensure that the ocular pupil will remain small enough, even with opaque centre CLs, to generate absolute scotomas representative of those experienced by patients with age-related macular disease. Using an Octopus 900 Perimeter ( www.Haag-Streit.com), kinetic visual fields (VFs) were measured in five normally-sighted subjects using a V4e Goldmann target with CLs that had central opaque areas with diameters of 2.8, 3.0, and 3.2 mm. To control pupil size, VFs were measured with background perimeter bowl luminances of 10, 585, and 1155 cd m -2 . Subjects attempted to (i) fixate the bowl centre; and (ii) place the scotoma edge at the bowl fixation target (eccentric viewing). As predicted, there was a direct relationship between scotoma size and both luminance level and diameter of the opacity. Mean scotoma diameters were 0°, 17.6° and 22°, for the low, medium and high bowl luminances, respectively. Scotoma size was determined primarily by the difference between the diameters of CL opacity and the entrance pupil of the eye and the axial separation between them, and between-subject differences in pupil diameters contributed most to the between-subject variability in scotoma diameter at each light level (SD: 6.01°). Scotoma displacement during eccentric fixation confirmed the gaze-contingent characteristics of this experimental model. It is possible to induce a gaze-contingent absolute scotoma and hence mimic central vision loss using centrally-opaque CLs provided that the CL opacity is larger than the entrance pupil of the eye. This simulation tool will, therefore, be ineffective at low environmental light levels (as shown previously) if the entrance pupil of the eye is larger than the CL opacity. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

SN Ia archaeology: Searching for the relics of progenitors past

NASA Astrophysics Data System (ADS)

Woods, Tyrone E.; Gilfanov, Marat; Clocchiatti, Alejandro; Rest, Armin

2016-06-01

Despite the critical role that SNe Ia play in the chemical enrichment of the Universe and their great importance in measuring cosmological distances, we still don't know for certain how they arise. In the canonical form of the ``single-degenerate'' scenario, a white dwarf grows through the nuclear burning of matter accreted at its surface from some companion star. This renders it a hot, luminous object (a supersoft X-ray source or SSS, 10^5-10^6K, 10^{38} erg/s) for up to a million years prior to explosion. Past efforts to directly detect the progenitors of very recent, nearby SNe Ia in archival soft X-ray images have produced only upper limits, and are only constraining assuming progenitors with much higher temperatures than known SSSs. In this talk, I will outline an alternative approach: given that such objects should be strong sources of ionizing radiation, one may instead search the environment surrounding nearby SN Ia remnants for interstellar matter ionized by the progenitor. Such fossil nebulae should extend out to tens of parsecs and linger for roughly the recombination timescale in the ISM, of order 10,000 — 100,000 years. Progress on this front has been hampered by the failure to detect nebulae surrounding most known SSSs using 1m class telescopes in the early 1990s. I will present new benchmark calculations for the emission-line nebulae expected to surround such objects, demonstrating that previous non-detections are entirely consistent with the low ISM densities expected in the vicinity of most SN Ia progenitors (Woods & Gilfanov, 2016). Modern large optical telescopes are now well able to reach the required limiting surface brightness needed to find such faint emission. With this in mind, I will introduce our new narrow-band survey for fossil nebulae surrounding young Magellanic SN Ia remnants and SSSs, already underway using the Magellan Baade telescope (PI: Alejandro Clocchiatti). In addition to opening a new era of SN Ia archaeology, I will show how our deep observations can also serve as a new probe of the structure of the ISM in nearby galaxies.

Astronomy. ASASSN-15lh: A highly super-luminous supernova.

PubMed

Dong, Subo; Shappee, B J; Prieto, J L; Jha, S W; Stanek, K Z; Holoien, T W-S; Kochanek, C S; Thompson, T A; Morrell, N; Thompson, I B; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Brown, J S; Bufano, F; Chen, Ping; Conseil, E; Danilet, A B; Falco, E; Grupe, D; Kiyota, S; Masi, G; Nicholls, B; Olivares E, F; Pignata, G; Pojmanski, G; Simonian, G V; Szczygiel, D M; Woźniak, P R

2016-01-15

We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu ,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10(45) ergs s(-1), which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10(52) ergs, challenging the magnetar model for its engine. Copyright © 2016, American Association for the Advancement of Science.

Impact of Intestinal Microbiota on Intestinal Luminal Metabolome

PubMed Central

Matsumoto, Mitsuharu; Kibe, Ryoko; Ooga, Takushi; Aiba, Yuji; Kurihara, Shin; Sawaki, Emiko; Koga, Yasuhiro; Benno, Yoshimi

2012-01-01

Low–molecular-weight metabolites produced by intestinal microbiota play a direct role in health and disease. In this study, we analyzed the colonic luminal metabolome using capillary electrophoresis mass spectrometry with time-of-flight (CE-TOFMS) —a novel technique for analyzing and differentially displaying metabolic profiles— in order to clarify the metabolite profiles in the intestinal lumen. CE-TOFMS identified 179 metabolites from the colonic luminal metabolome and 48 metabolites were present in significantly higher concentrations and/or incidence in the germ-free (GF) mice than in the Ex-GF mice (p < 0.05), 77 metabolites were present in significantly lower concentrations and/or incidence in the GF mice than in the Ex-GF mice (p < 0.05), and 56 metabolites showed no differences in the concentration or incidence between GF and Ex-GF mice. These indicate that intestinal microbiota highly influenced the colonic luminal metabolome and a comprehensive understanding of intestinal luminal metabolome is critical for clarifying host-intestinal bacterial interactions. PMID:22724057

Mechanisms of intragastric pH sensing.

PubMed

Goo, Tyralee; Akiba, Yasutada; Kaunitz, Jonathan D

2010-12-01

Luminal amino acids and lack of luminal acidity as a result of acid neutralization by intragastric foodstuffs are powerful signals for acid secretion. Although the hormonal and neural pathways underlying this regulatory mechanism are well understood, the nature of the gastric luminal pH sensor has been enigmatic. In clinical studies, high pH, tryptic peptides, and luminal divalent metals (Ca(2+) and Mg(2+)) increase gastrin release and acid production. The calcium-sensing receptor (CaSR), first described in the parathyroid gland but expressed on gastric G cells, is a logical candidate for the gastric acid sensor. Because CaSR ligands include amino acids and divalent metals, and because extracellular pH affects ligand binding in the pH range of the gastric content, its pH, metal, and nutrient-sensing functions are consistent with physiologic observations. The CaSR is thus an attractive candidate for the gastric luminal sensor that is part of the neuroendocrine negative regulatory loop for acid secretion.

Visual evoked potential assessment of the effects of glaucoma on visual subsystems.

PubMed

Greenstein, V C; Seliger, S; Zemon, V; Ritch, R

1998-06-01

The purpose of this study is to test the hypothesis that glaucoma leads to selective deficits in parallel pathways or channels. Sweep VEPs were obtained to isolated-check stimuli that were modulated sinusoidally in either isoluminant chromatic contrast or in positive and negative luminance contrast. Response functions were obtained from 14 control subjects, 15 patients with open-angle glaucoma, and seven glaucoma suspects. For all three groups of subjects we found characteristic differences between the VEP response functions to isoluminant chromatic contrast stimuli and to luminance contrast stimuli. The isoluminant chromatic stimulus conditions appeared to favor activity of the P-pathway, whereas the luminance contrast stimuli at low depths of modulation favored M-pathway activity. VEP responses for patients with OAG were significantly reduced for chromatic contrast and luminance contrast conditions, whereas VEP responses for glaucoma suspects were significantly reduced only for the 15-Hz positive luminance contrast condition. Our results suggest that both M- and P-pathways are affected by glaucoma.

The skylight gradient of luminance helps sandhoppers in sun and moon identification.

PubMed

Ugolini, Alberto; Galanti, Giuditta; Mercatelli, Luca

2012-08-15

To return to the ecologically optimal zone of the beach, the sandhopper Talitrus saltator (Montagu) maintains a constant sea-land direction based on the sun and moon compasses. In this study, we investigated the role of the skylight gradient of luminance in sun and moon identification under natural and artificial conditions of illumination. Clock-shifted (inverted) sandhoppers tested under the sun (during their subjective night) and under the full moon (during their subjective day) exhibit orientation in accordance with correct identification of the sun and the moon at night. Tested in artificial conditions of illumination at night without the artificial gradient of luminance, the artificial astronomical cue is identified as the moon even when the conditions of illumination allow sun compass orientation during the day. When the artificial gradient of luminance is added, the artificial astronomical cue is identified as the sun. The role of the sky gradient of luminance in sun and moon identification is discussed on the basis of present and past findings.

Modular Representation of Luminance Polarity In the Superficial Layers Of Primary Visual Cortex

PubMed Central

Smith, Gordon B.; Whitney, David E.; Fitzpatrick, David

2016-01-01

Summary The spatial arrangement of luminance increments (ON) and decrements (OFF) falling on the retina provides a wealth of information used by central visual pathways to construct coherent representations of visual scenes. But how the polarity of luminance change is represented in the activity of cortical circuits remains unclear. Using wide-field epifluorescence and two-photon imaging we demonstrate a robust modular representation of luminance polarity (ON or OFF) in the superficial layers of ferret primary visual cortex. Polarity-specific domains are found with both uniform changes in luminance and single light/dark edges, and include neurons selective for orientation and direction of motion. The integration of orientation and polarity preference is evident in the selectivity and discrimination capabilities of most layer 2/3 neurons. We conclude that polarity selectivity is an integral feature of layer 2/3 neurons, ensuring that the distinction between light and dark stimuli is available for further processing in downstream extrastriate areas. PMID:26590348

Highly Efficient Visible Colloidal Lead-Halide Perovskite Nanocrystal Light-Emitting Diodes

NASA Astrophysics Data System (ADS)

Yan, Fei; Xing, Jun; Xing, Guichuan; Quan, Lina; Tan, Swee Tiam; Zhao, Jiaxin; Su, Rui; Zhang, Lulu; Chen, Shi; Zhao, Yawen; Huan, Alfred; Sargent, Edward H.; Xiong, Qihua; Demir, Hilmi Volkan

2018-05-01

Lead-halide perovskites have been attracting attention for potential use in solid-state lighting. Following the footsteps of solar cells, the field of perovskite light-emitting diodes (PeLEDs) has been growing rapidly. Their application prospects in lighting, however, remain still uncertain due to a variety of shortcomings in device performance including their limited levels of luminous efficiency achievable thus far. Here we show high-efficiency PeLEDs based on colloidal perovskite nanocrystals (PeNCs) synthesized at room temperature possessing dominant first-order excitonic radiation (enabling a photoluminescence quantum yield of 71% in solid film), unlike in the case of bulk perovskites with slow electron-hole bimolecular radiative recombination (a second-order process). In these PeLEDs, by reaching charge balance in the recombination zone, we find that the Auger nonradiative recombination, with its significant role in emission quenching, is effectively suppressed in low driving current density range. In consequence, these devices reach a record high maximum external quantum efficiency of 12.9% reported to date and an unprecedentedly high power efficiency of 30.3 lm W-1 at luminance levels above 1000 cd m-2 as required for various applications. These findings suggest that, with feasible levels of device performance, the PeNCs hold great promise for their use in LED lighting and displays.

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

PubMed

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

2014-02-01

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

Surface regions of illusory images are detected with a slower processing speed than those of luminance-defined images.

PubMed

Mihaylova, Milena; Manahilov, Velitchko

2010-11-24

Research has shown that the processing time for discriminating illusory contours is longer than for real contours. We know, however, little whether the visual processes, associated with detecting regions of illusory surfaces, are also slower as those responsible for detecting luminance-defined images. Using a speed-accuracy trade-off (SAT) procedure, we measured accuracy as a function of processing time for detecting illusory Kanizsa-type and luminance-defined squares embedded in 2D static luminance noise. The data revealed that the illusory images were detected at slower processing speed than the real images, while the points in time, when accuracy departed from chance, were not significantly different for both stimuli. The classification images for detecting illusory and real squares showed that observers employed similar detection strategies using surface regions of the real and illusory squares. The lack of significant differences between the x-intercepts of the SAT functions for illusory and luminance-modulated stimuli suggests that the detection of surface regions of both images could be based on activation of a single mechanism (the dorsal magnocellular visual pathway). The slower speed for detecting illusory images as compared to luminance-defined images could be attributed to slower processes of filling-in of regions of illusory images within the dorsal pathway.

Accurate method for luminous transmittance and signal detection quotients measurements in sunglasses lenses

NASA Astrophysics Data System (ADS)

Loureiro, A. D.; Gomes, L. M.; Ventura, L.

2018-02-01

The international standard ISO 12312-1 proposes transmittance tests that quantify how dark sunglasses lenses are and whether or not they are suitable for driving. To perform these tests a spectrometer is required. In this study, we present and analyze theoretically an accurate alternative method for performing these measurements using simple components. Using three LEDs and a four-channel sensor we generated weighting functions similar to the standard ones for luminous and traffic lights transmittances. From 89 sunglasses lens spectroscopy data, we calculated luminous transmittance and signal detection quotients using our obtained weighting functions and the standard ones. Mean-difference Tukey plots were used to compare the results. All tested sunglasses lenses were classified in the right category and correctly as suitable or not for driving. The greatest absolute errors for luminous transmittance and red, yellow, green and blue signal detection quotients were 0.15%, 0.17, 0.06, 0.04 and 0.18, respectively. This method will be used in a device capable to perform transmittance tests (visible, traffic lights and ultraviolet (UV)) according to the standard. It is important to measure rightly luminous transmittance and relative visual attenuation quotients to report correctly whether or not sunglasses are suitable for driving. Moreover, standard UV requirements depend on luminous transmittance.

Relationship of the luminous bacterial symbiont of the Caribbean flashlight fish, Kryptophanaron alfredi (family Anomalopidae) to other luminous bacteria based on bacterial luciferase (luxA) genes.

PubMed

Haygood, M G

1990-01-01

Flashlight fishes (family Anomalopidae) have light organs that contain luminous bacterial symbionts. Although the symbionts have not yet been successfully cultured, the luciferase genes have been cloned directly from the light organ of the Caribbean species, Kryptophanaron alfredi. The goal of this project was to evaluate the relationship of the symbiont to free-living luminous bacteria by comparison of genes coding for bacterial luciferase (lux genes). Hybridization of a lux AB probe from the Kryptophanaron alfredi symbiont to DNAs from 9 strains (8 species) of luminous bacteria showed that none of the strains tested had lux genes highly similar to the symbiont. The most similar were a group consisting of Vibrio harveyi, Vibrio splendidus and Vibrio orientalis. The nucleotide sequence of the luciferase alpha subunit gene luxA) of the Kryptophanaron alfredi symbiont was determined in order to do a more detailed comparison with published luxA sequences from Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi. The hybridization results, sequence comparisons and the mol% G + C of the Kryptophanaron alfredi symbiont luxA gene suggest that the symbiont may be considered as a new species of luminous Vibrio related to Vibrio harveyi.

An Exponential Luminous Efficiency Model for Hypervelocity Impact into Regolith

NASA Technical Reports Server (NTRS)

Swift, W. R.; Moser, D. E.; Suggs, R. M.; Cooke, W. J.

2011-01-01

The flash of thermal radiation produced as part of the impact-crater forming process can be used to determine the energy of the impact if the luminous efficiency is known. From this energy the mass and, ultimately, the mass flux of similar impactors can be deduced. The luminous efficiency, eta, is a unique function of velocity with an extremely large variation in the laboratory range of under 6 km/s but a necessarily small variation with velocity in the meteoric range of 20 to 70 km/s. Impacts into granular or powdery regolith, such as that on the moon, differ from impacts into solid materials in that the energy is deposited via a serial impact process which affects the rate of deposition of internal (thermal) energy. An exponential model of the process is developed which differs from the usual polynomial models of crater formation. The model is valid for the early time portion of the process and focuses on the deposition of internal energy into the regolith. The model is successfully compared with experimental luminous efficiency data from both laboratory impacts and from lunar impact observations. Further work is proposed to clarify the effects of mass and density upon the luminous efficiency scaling factors. Keywords hypervelocity impact impact flash luminous efficiency lunar impact meteoroid 1

Contribution of color signals to ocular following responses.

PubMed

Matsuura, Kiyoto; Kawano, Kenji; Inaba, Naoko; Miura, Kenichiro

2016-10-01

Ocular following responses (OFRs) are elicited at ultra-short latencies (< 60 ms) by sudden movements of the visual scene. In this study, we investigated the roles of color signals in OFRs in monkeys. To make physiologically isoluminant sinusoidal color gratings, we estimated the physiologically isoluminant points using OFRs and found that the physiologically isoluminant points were nearly independent of the spatiotemporal frequency of the gratings. We recorded OFRs induced by the motion of physiologically isoluminant color gratings and found that OFRs elicited by the motion of color gratings had different spatiotemporal frequency tuning from those elicited by the motion of luminance gratings. Additionally, OFRs to isoluminant color gratings had smaller peak responses, suggesting that color signals weakly contribute to OFRs compared with luminance signals. OFRs to the motion of stimuli composed of luminance and color signals were also examined. We found that color signals largely contributed to OFRs under low luminance signals regardless of whether color signals moved in the same or opposite direction to luminance signals. These results provide evidence of the multichannel visual computations underlying motor responses. We conclude that, in everyday situations, color information contributes cooperatively with luminance information to the generation of ocular tracking behaviors. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Second-level post-occupancy evaluation (POE) analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, B.; Fisher, W.; Marans, R.W.

1989-02-14

Findings from a detailed analysis of post-occupancy evaluation data, sponsored by LRI, which involved thirteen office buildings typical of current design practice, will be discussed. Analysis of the data indicates that occupant satisfaction can be related to type of lighting system, presence of daylight, and patterns of luminance in the office. 15 refs., 9 figs., 3 tabs.

Dynamin-mediated endocytosis is required for tube closure, cell intercalation, and biased apical expansion during epithelial tubulogenesis in the Drosophila ovary

PubMed Central

Peters, Nathaniel C.

2015-01-01

Most metazoans are able to grow beyond a few hundred cells and to support differentiated tissues because they elaborate multicellular, epithelial tubes that are indispensable for nutrient and gas exchange. To identify and characterize the cellular behaviors and molecular mechanisms required for the morphogenesis of epithelial tubes (i.e., tubulogenesis), we have turned to the D. melanogaster ovary. Here, epithelia surrounding the developing egg chambers first pattern, then form and extend a set of simple, paired, epithelial tubes, the dorsal appendage (DA) tubes, and they create these structures in the absence of cell division or cell death. This genetically tractable system lets us assess the relative contributions that coordinated changes in cell shape, adhesion, orientation, and migration make to basic epithelial tubulogenesis. We find that Dynamin, a conserved regulator of endocytosis and the cytoskeleton, serves a key role in DA tubulogenesis. We demonstrate that Dynamin is required for distinct aspects of DA tubulogenesis: DA-tube closure, DA-tube-cell intercalation, and biased apical-luminal cell expansion. We provide evidence that Dynamin promotes these processes by facilitating endocytosis of cell-cell and cell-matrix adhesion complexes, and we find that precise levels and sub-cellular distribution of E-Cadherin and specific Integrin subunits impact DA tubulogenesis. Thus, our studies identify novel morphogenetic roles (i.e., tube closure and biased apical expansion), and expand upon established roles (i.e., cell intercalation and adhesion remodeling), for Dynamin in tubulogenesis. PMID:26542010

Connection method of separated luminal regions of intestine from CT volumes

NASA Astrophysics Data System (ADS)

Oda, Masahiro; Kitasaka, Takayuki; Furukawa, Kazuhiro; Watanabe, Osamu; Ando, Takafumi; Hirooka, Yoshiki; Goto, Hidemi; Mori, Kensaku

2015-03-01

This paper proposes a connection method of separated luminal regions of the intestine for Crohn's disease diagnosis. Crohn's disease is an inflammatory disease of the digestive tract. Capsule or conventional endoscopic diagnosis is performed for Crohn's disease diagnosis. However, parts of the intestines may not be observed in the endoscopic diagnosis if intestinal stenosis occurs. Endoscopes cannot pass through the stenosed parts. CT image-based diagnosis is developed as an alternative choice of the Crohn's disease. CT image-based diagnosis enables physicians to observe the entire intestines even if stenosed parts exist. CAD systems for Crohn's disease using CT volumes are recently developed. Such CAD systems need to reconstruct separated luminal regions of the intestines to analyze intestines. We propose a connection method of separated luminal regions of the intestines segmented from CT volumes. The luminal regions of the intestines are segmented from a CT volume. The centerlines of the luminal regions are calculated by using a thinning process. We enumerate all the possible sequences of the centerline segments. In this work, we newly introduce a condition using distance between connected ends points of the centerline segments. This condition eliminates unnatural connections of the centerline segments. Also, this condition reduces processing time. After generating a sequence list of the centerline segments, the correct sequence is obtained by using an evaluation function. We connect the luminal regions based on the correct sequence. Our experiments using four CT volumes showed that our method connected 6.5 out of 8.0 centerline segments per case. Processing times of the proposed method were reduced from the previous method.

Optimal combination of illusory and luminance-defined 3-D surfaces: A role for ambiguity.

PubMed

Hartle, Brittney; Wilcox, Laurie M; Murray, Richard F

2018-04-01

The shape of the illusory surface in stereoscopic Kanizsa figures is determined by the interpolation of depth from the luminance edges of adjacent inducing elements. Despite ambiguity in the position of illusory boundaries, observers reliably perceive a coherent three-dimensional (3-D) surface. However, this ambiguity may contribute additional uncertainty to the depth percept beyond what is expected from measurement noise alone. We evaluated the intrinsic ambiguity of illusory boundaries by using a cue-combination paradigm to measure the reliability of depth percepts elicited by stereoscopic illusory surfaces. We assessed the accuracy and precision of depth percepts using 3-D Kanizsa figures relative to luminance-defined surfaces. The location of the surface peak was defined by illusory boundaries, luminance-defined edges, or both. Accuracy and precision were assessed using a depth-discrimination paradigm. A maximum likelihood linear cue combination model was used to evaluate the relative contribution of illusory and luminance-defined signals to the perceived depth of the combined surface. Our analysis showed that the standard deviation of depth estimates was consistent with an optimal cue combination model, but the points of subjective equality indicated that observers consistently underweighted the contribution of illusory boundaries. This systematic underweighting may reflect a combination rule that attributes additional intrinsic ambiguity to the location of the illusory boundary. Although previous studies show that illusory and luminance-defined contours share many perceptual similarities, our model suggests that ambiguity plays a larger role in the perceptual representation of illusory contours than of luminance-defined contours.

Apoptosis-linked Gene-2 (ALG-2)/Sec31 Interactions Regulate Endoplasmic Reticulum (ER)-to-Golgi Transport

PubMed Central

Helm, Jared R.; Bentley, Marvin; Thorsen, Kevin D.; Wang, Ting; Foltz, Lauren; Oorschot, Viola; Klumperman, Judith; Hay, Jesse C.

2014-01-01

Luminal calcium released from secretory organelles has been suggested to play a regulatory role in vesicle transport at several steps in the secretory pathway; however, its functional roles and effector pathways have not been elucidated. Here we demonstrate for the first time that specific luminal calcium depletion leads to a significant decrease in endoplasmic reticulum (ER)-to-Golgi transport rates in intact cells. Ultrastructural analysis revealed that luminal calcium depletion is accompanied by increased accumulation of intermediate compartment proteins in COPII buds and clusters of unfused COPII vesicles at ER exit sites. Furthermore, we present several lines of evidence suggesting that luminal calcium affected transport at least in part through calcium-dependent interactions between apoptosis-linked gene-2 (ALG-2) and the Sec31A proline-rich region: 1) targeted disruption of ALG-2/Sec31A interactions caused severe defects in ER-to-Golgi transport in intact cells; 2) effects of luminal calcium and ALG-2/Sec31A interactions on transport mutually required each other; and 3) Sec31A function in transport required luminal calcium. Morphological phenotypes of disrupted ALG-2/Sec31A interactions were characterized. We found that ALG-2/Sec31A interactions were not required for the localization of Sec31A to ER exit sites per se but appeared to acutely regulate the stability and trafficking of the cargo receptor p24 and the distribution of the vesicle tether protein p115. These results represent the first outline of a mechanism that connects luminal calcium to specific protein interactions regulating vesicle trafficking machinery. PMID:25006245

The effect of luminous intensity on the attraction of phlebotomine sand flies to light traps.

PubMed

Lima-Neto, Abdias R; Costa-Neta, Benedita M; da Silva, Apoliana Araújo; Brito, Jefferson M; Aguiar, João V C; Ponte, Islana S; Silva, Francinaldo S

2018-05-04

To improve the efficiency of light traps in collecting phlebotomine sand flies, the potential effects of luminous intensity on the attraction of these insects to traps were evaluated. Sand flies were collected with Hooper Pugedo (HP) light traps fitted with 5-mm light-emitting diodes (LED) bulbs: green (520 nm wavelength-10,000, 15,000 and 20,000 millicandela (mcd) and blue (470 nm-4,000, 12,000 and 15,000 mcd). A total of 3,264 sand flies comprising 13 species were collected. The collected species were Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae) (52.48%), Evandromyia evandroi (Costa Lima & Antunes, 1939) (Diptera: Psychodidae) (32.90%) and Micropygomyia goiana (Martins, Falcão, & Silva) (Diptera: Psychodidae) (9.76%). An increase in luminous intensity of the LEDs increased the size of the sand fly catch. The lower luminous intensity of green (10,000 mcd) attracted an average of 13.7 ± 2.8 sand flies/trap per night and the other luminous intensities accounted for a mean of 24.1 ± 4.0 (15,000 mcd) and 28.2 ± 5.0 (20,000 mcd) sand flies/trap per night. Regarding the blue wavelength, the lower luminous intensity (4,000 mcd) attracted an average of 27.4 ± 4.1 sand flies/trap per night, followed by 12,000 mcd (37.6 ± 8.7) and 15,000 mcd (40.5 ± 7.3). Based on our data, the luminous intensity of light traps should be considered when developing light traps for monitoring or controlling phlebotomine sand flies.

Intrinsic breast tumor subtypes, race, and long-term survival in the Carolina Breast Cancer Study.

PubMed

O'Brien, Katie M; Cole, Stephen R; Tse, Chiu-Kit; Perou, Charles M; Carey, Lisa A; Foulkes, William D; Dressler, Lynn G; Geradts, Joseph; Millikan, Robert C

2010-12-15

Previous research identified differences in breast cancer-specific mortality across 4 intrinsic tumor subtypes: luminal A, luminal B, basal-like, and human epidermal growth factor receptor 2 positive/estrogen receptor negative (HER2(+)/ER(-)). We used immunohistochemical markers to subtype 1,149 invasive breast cancer patients (518 African American, 631 white) in the Carolina Breast Cancer Study, a population-based study of women diagnosed with breast cancer. Vital status was determined through 2006 using the National Death Index, with median follow-up of 9 years. Cancer subtypes luminal A, luminal B, basal-like, and HER2(+)/ER(-) were distributed as 64%, 11%, 11%, and 5% for whites, and 48%, 8%, 22%, and 7% for African Americans, respectively. Breast cancer mortality was higher for participants with HER2(+)/ER(-) and basal-like breast cancer compared with luminal A and B. African Americans had higher breast cancer-specific mortality than whites, but the effect of race was statistically significant only among women with luminal A breast cancer. However, when compared with the luminal A subtype within racial categories, mortality for participants with basal-like breast cancer was higher among whites (HR = 2.0, 95% CI: 1.2-3.4) than African Americans (HR = 1.5, 95% CI: 1.0-2.4), with the strongest effect seen in postmenopausal white women (HR = 3.9, 95% CI: 1.5-10.0). Our results confirm the association of basal-like breast cancer with poor prognosis and suggest that basal-like breast cancer is not an inherently more aggressive disease in African American women compared with whites. Additional analyses are needed in populations with known treatment profiles to understand the role of tumor subtypes and race in breast cancer mortality, and in particular our finding that among women with luminal A breast cancer, African Americans have higher mortality than whites. ©2010 AACR.

Glutamate 90 at the Luminal Ion Gate of Sarcoplasmic Reticulum Ca2+-ATPase Is Critical for Ca2+ Binding on Both Sides of the Membrane*

PubMed Central

Clausen, Johannes D.; Andersen, Jens Peter

2010-01-01

The roles of Ser72, Glu90, and Lys297 at the luminal ends of transmembrane helices M1, M2, and M4 of sarcoplasmic reticulum Ca2+-ATPase were examined by transient and steady-state kinetic analysis of mutants. The dependence on the luminal Ca2+ concentration of phosphorylation by Pi (“Ca2+ gradient-dependent E2P formation”) showed a reduction of the apparent affinity for luminal Ca2+ in mutants with alanine or leucine replacement of Glu90, whereas arginine replacement of Glu90 or Ser72 allowed E2P formation from Pi even at luminal Ca2+ concentrations much too small to support phosphorylation in wild type. The latter mutants further displayed a blocked dephosphorylation of E2P and an increased rate of conversion of the ADP-sensitive E1P phosphoenzyme intermediate to ADP-insensitive E2P as well as insensitivity of the E2·BeF3− complex to luminal Ca2+. Altogether, these findings, supported by structural modeling, indicate that the E2P intermediate is stabilized in the mutants with arginine replacement of Glu90 or Ser72, because the positive charge of the arginine side chain mimics Ca2+ occupying a luminally exposed low affinity Ca2+ site of E2P, thus identifying an essential locus (a “leaving site”) on the luminal Ca2+ exit pathway. Mutants with alanine or leucine replacement of Glu90 further displayed a marked slowing of the Ca2+ binding transition as well as slowing of the dissociation of Ca2+ from Ca2E1 back toward the cytoplasm, thus demonstrating that Glu90 is also critical for the function of the cytoplasmically exposed Ca2+ sites on the opposite side of the membrane relative to where Glu90 is located. PMID:20421308

The effect of lane line width and contrast upon lanekeeping.

PubMed

McKnight, A S; McKnight, A J; Tippetts, A S

1998-09-01

The combined effect of lane line width and line-pavement contrast upon lanekeeping was studied through simulation. Some 124 subjects, ages 17-79 (x = 56.30), 52% male, each performed 42 trials over road segments representing three levels of width crossed with 14 line-pavement contrast ratios. Lanekeeping performance was recorded in terms of heading error, position error, lane excursions and road excursions. Subjects were stratified into two levels of ability on a combined measure of visual, attentional and psychomotor variables known to decline with age. Contrast and width had a negligible effect upon performance except at very low contrast ratios, ca 1.02 at high pavement luminance levels (e.g. concrete) and 1.04 for very low luminance levels (e.g. asphalt). These ratios are similar to those encountered at night on wet roads. Mean overall performance error at the low contrast ratios increased by a factor of 1.6, 1.8 and 2.2 for 8, 6 and 4" widths, respectively. Lower ability subjects exhibited greater error at almost all contrast ratios, with no consistent relationship between degree of decrement and either width or contrast. The results suggest that lane line width and contrast have a negligible effect upon lanekeeping performance except at extremely low levels of contrast, where both have large effects. Further research in the roadway environment is needed to determine the relationships of line width and contrast ratio to lanekeeping on normal and degraded surface conditions.

Detection of heavy metal resistance bioluminescence bacteria using microplate bioassay method.

PubMed

Ranjitha, P; Karthy, E S

2012-01-01

Effects of different heavy metals on Vibrio harveyi, V. fischeri, Photobacterium phosphoreum and P. leiognathi were examined. Checkerboard assay was used for the detection of the natural metal tolerance levels of a large number of marine luminous eubacteria. 57 strains of luminous bacteria were investigated for their natural patterns of heavy metal tolerance. The behaviors of these strains were not homogeneous with respect to all metals tested, even within the strains belonging to the same genus. At least 1 to 4 different MICs were detected for every metal except barium and cobalt. Isolated bacteria were tested for the presence of plasmids using the modified alkaline lysis method, was effective for identification of plasmids of different sizes. This study revealed the frequency of the occurrence of plasmids in heavy metal resistance bacteria and inferred that plasmids are highly ubiquitous and predominant in most heavy metal resistant bacteria.

Investigation of Saturation Effects in Ceramic Phosphors for Laser Lighting

PubMed Central

Krasnoshchoka, Anastasiia; Dam-Hansen, Carsten; Corell, Dennis Dan; Petersen, Paul Michael

2017-01-01

We report observations of saturation effects in a Ce:LuAG and Eu-doped nitride ceramic phosphor for conversion of blue laser light for white light generation. The luminous flux from the phosphors material increases linearly with the input power until saturation effects limit the conversion. It is shown that the temperature of the phosphor layer influences the saturation power level and the conversion efficiency. It is also shown that the correlated color temperature (CCT), phosphor conversion efficiency and color rendering index (CRI) are dependent both on the incident power and spot size diameter of the illumination. A phosphor conversion efficiency up to 140.8 lm/W with CRI of 89.4 was achieved. The saturation in a ceramic phosphor, when illuminated by high intensity laser diodes, is estimated to play the main role in limiting the available luminance from laser-based lighting systems. PMID:29292770

Implication of high dynamic range and wide color gamut content distribution

NASA Astrophysics Data System (ADS)

Lu, Taoran; Pu, Fangjun; Yin, Peng; Chen, Tao; Husak, Walt

2015-09-01

High Dynamic Range (HDR) and Wider Color Gamut (WCG) content represents a greater range of luminance levels and a more complete reproduction of colors found in real-world scenes. The current video distribution environments deliver Standard Dynamic Range (SDR) signal. Therefore, there might be some significant implication on today's end-to-end ecosystem from content creation to distribution and finally to consumption. For SDR content, the common practice is to apply compression on Y'CbCr 4:2:0 using gamma transfer function and non-constant luminance 4:2:0 chroma subsampling. For HDR and WCG content, it is desirable to examine if such signal format still works well for compression, and it is interesting to know if the overall system performance can be further improved by exploring different signal formats and processing workflows. In this paper, we will provide some of our insight into those problems.

Edges, colour and awareness in blindsight.

PubMed

Alexander, Iona; Cowey, Alan

2010-06-01

It remains unclear what is being processed in blindsight in response to faces, colours, shapes, and patterns. This was investigated in two hemianopes with chromatic and achromatic stimuli with sharp or shallow luminance or chromatic contrast boundaries or temporal onsets. Performance was excellent only when stimuli had sharp spatial boundaries. When discrimination between isoluminant coloured Gaussians was good it declined to chance levels if stimulus onset was slow. The ability to discriminate between instantaneously presented colours in the hemianopic field depended on their luminance, indicating that wavelength discrimination totally independent of other stimulus qualities is absent. When presented with narrow-band colours the hemianopes detected a stimulus maximally effective for S-cones but invisible to M- and L-cones, indicating that blindsight is mediated not just by the mid-brain, which receives no S-cone input, or that the rods contribute to blindsight. The results show that only simple stimulus features are processed in blindsight. 2010 Elsevier Inc. All rights reserved.

The inevitable youthfulness of known high-redshift radio galaxies

NASA Astrophysics Data System (ADS)

Blundell, Katherine M.; Rawlings, Steve

1999-05-01

Some galaxies are very luminous in the radio part of the spectrum. These `radio galaxies' have extensive (hundreds of kiloparsecs) lobes of emission powered by plasma jets originating at a central black hole. Some radio galaxies can be seen at very high redshifts, where in principle they can serve as probes of the early evolution of the Universe. Here we show that, for any model of radio-galaxy evolution in which the luminosity decreases with time after an initial rapid increase (that is, essentially all reasonable models), all observable high-redshift radio galaxies must be seen when the lobes are less than 107 years old. This means that high-redshift radio galaxies can be used as a high-time-resolution probe of evolution in the early Universe. Moreover, this result explains many observed trends of radio-galaxy properties with redshift, without needing to invoke explanations based on cosmology or strong evolution of the surrounding intergalactic medium with cosmic time, thereby avoiding conflict with current theories of structure formation.

Combined percutaneous and transarterial devascularisation of juvenile nasopharyngeal angiofibroma with protection of internal carotid artery: A modification of the technique.

PubMed

Borota, Ljubisa; Mahmoud, Ehab; Nyberg, Christoffer; Ekberg, Tomas

2015-06-01

Juvenile nasal angiofibroma (JNA) is a hypervascularised, benign, but locally aggressive tumour that grows in the posterior, upper part of the nasal cavity and invades surrounding anatomical structures. The treatment of choice is surgical removal, but complete resection of the tumour can be hampered because of profuse perioperative bleeding. Preoperative embolisation of the tumour has been proposed as an effective method for prevention of perioperative bleeding, thereby shortening of the time of the operation. In this report of five cases, we describe successful preoperative devascularisation of the tumour by applying a modified method of direct intratumoural injection of the liquid embolic agent Onyx combined with protection of the internal carotid artery. The control of bleeding during the embolisation and occlusion of the maxillary or sphenopalatine artery was achieved by using a bi-luminal balloon catheter. Such use of the dual-lumen catheter in treatment of JNA has not been reported so far in the medical literature. © The Author(s) 2015.

Combined percutaneous and transarterial devascularisation of juvenile nasopharyngeal angiofibroma with protection of internal carotid artery: A modification of the technique

PubMed Central

Mahmoud, Ehab; Nyberg, Christoffer; Ekberg, Tomas

2015-01-01

Juvenile nasal angiofibroma (JNA) is a hypervascularised, benign, but locally aggressive tumour that grows in the posterior, upper part of the nasal cavity and invades surrounding anatomical structures. The treatment of choice is surgical removal, but complete resection of the tumour can be hampered because of profuse perioperative bleeding. Preoperative embolisation of the tumour has been proposed as an effective method for prevention of perioperative bleeding, thereby shortening of the time of the operation. In this report of five cases, we describe successful preoperative devascularisation of the tumour by applying a modified method of direct intratumoural injection of the liquid embolic agent Onyx combined with protection of the internal carotid artery. The control of bleeding during the embolisation and occlusion of the maxillary or sphenopalatine artery was achieved by using a bi-luminal balloon catheter. Such use of the dual-lumen catheter in treatment of JNA has not been reported so far in the medical literature. PMID:25991005

Infrared fine-structure line diagnostics of shrouded active galactic nuclei

NASA Technical Reports Server (NTRS)

Voit, G. M.

1993-01-01

Far-infrared spectroscopy of celestial objects will improve dramatically in the coming decade, allowing astronomers to use fine-structure line emission to probe photoionized regions obscured in the optical band by thick clouds of dust. The ultraluminous far-IR galaxies revealed by IRAS, quasar-like in luminosity but smothered in molecular gas, probably conceal either immense starbursts or luminous active nuclei. In both scenarios, these objects ought to produce copious infrared fine-structure emission with several lines comparable to H(beta) in luminosity. This paper shows how these lines, if detected, can be used to determine the electron densities and far-IR obscurations of shrouded photoionized regions and to constrain the shape and ionization parameter of the ionizing spectra. The presence of (Ne V) emission in particular will distinguish shrouded AGN's from shrouded starbursts. Since all active galaxies photoionize at least some surrounding material, these diagnostics can also be applied to active galaxies in general and will aid in studying how an active nucleus interacts with the interstellar medium of its host galaxy.

New constraints on the TeV SNR shells RX J1713.7-3946 and HESS J1731-347

NASA Astrophysics Data System (ADS)

Puehlhofer, G.; Eger, P.; Doroshenko, V.; Cui, Y.; H. E. S. S. Collaboration

2016-06-01

Resolved TeV-emitting supernova remnants remain a small and precious class of sources to study cosmic ray acceleration in SNRs. We present new multi-wavelength results of the two prominent objects RX J1713.7-3946 and HESS J1731-347. For RX J1713.7-3946, extensive new H.E.S.S. data have permitted to study the nature of the TeV-emitting CR particles through improved broadband spectral studies, as well as through detailed investigations of morphological differences between TeV gamma-rays and X-rays. Concerning HESS J1731-347, the TeV morphology of the object and its surroundings has been studied using cosmic ray acceleration simulations of the object. The SNR also hosts a luminous X-ray emitting central compact object (CCO). Investigations of the CCO in X-rays and in the infrared have permitted to set interesting constraints on the SNR and its progenitor.

Epithelial adhesion molecules and the regulation of intestinal homeostasis during neutrophil transepithelial migration

PubMed Central

Sumagin, Ronen; Parkos, Charles A

2014-01-01

Epithelial adhesion molecules play essential roles in regulating cellular function and maintaining mucosal tissue homeostasis. Some form epithelial junctional complexes to provide structural support for epithelial monolayers and act as a selectively permeable barrier separating luminal contents from the surrounding tissue. Others serve as docking structures for invading viruses and bacteria, while also regulating the immune response. They can either obstruct or serve as footholds for the immune cells recruited to mucosal surfaces. Currently, it is well appreciated that adhesion molecules collectively serve as environmental cue sensors and trigger signaling events to regulate epithelial function through their association with the cell cytoskeleton and various intracellular adapter proteins. Immune cells, particularly neutrophils (PMN) during transepithelial migration (TEM), can modulate adhesion molecule expression, conformation, and distribution, significantly impacting epithelial function and tissue homeostasis. This review discusses the roles of key intestinal epithelial adhesion molecules in regulating PMN trafficking and outlines the potential consequences on epithelial function. PMID:25838976

Involvement of pterygoid venous plexus in patulous eustachian tube symptoms.

PubMed

Oshima, Takeshi; Ogura, Masaki; Kikuchi, Toshiaki; Hori, Yoko; Mugikura, Shunji; Higano, Shuichi; Takahashi, Shoki; Kawase, Tetsuaki; Kobayashi, Toshimitsu

2007-07-01

The pterygoid venous plexus (PVP) is an important factor in the mechanism of eustachian tube (ET) closure under conditions that can cause increased venous pressure in the head, such as during neck compression and postural change from the sitting/standing to the recumbent position. The symptoms of patulous ET are usually improved by neck compression or postural change (from sitting/standing to recumbent position). Venous congestion around the ET and/or gravitational change may be involved in the changing degree of symptoms, but its mechanism is not understood. This study investigated whether the PVP is involved. The dimensions of soft tissues surrounding ET were measured on magnetic resonance images before and after neck compression. The lateral pterygoid muscle became enlarged after neck compression. Simultaneously, the volume of venous plexus observed between the medial pterygoid muscle and tensor veli palatini muscle was increased. Such enlargement was probably due to blood pooling in the PVP, resulting in protrusion of the ET anterior wall to the luminal side, and decreased ET patency.

A series of shocks and edges in Abell 2219

DOE PAGES

Canning, R. E. A.; Allen, S. W.; Applegate, D. E.; ...

2016-09-22

Here, we present deep, 170 ks, Chandra X-ray observations of Abell 2219 (z = 0.23), one of the hottest and most X-ray luminous clusters known, and which is experiencing a major merger event. We discover a ‘horseshoe’ of high-temperature gas surrounding the ram-pressure-stripped, bright, hot, X-ray cores. We confirm an X-ray shock front located north-west of the X-ray centroid and along the projected merger axis. We also find a second shock front to the south-east of the X-ray centroid making this only the second cluster where both the shock and reverse shock are confirmed with X-ray temperature measurements. We alsomore » present evidence for a possible sloshing cold front in the ‘remnant tail’ of one of the sub-cluster cores. The cold front and north-west shock front geometrically bound the radio halo and appear to be directly influencing the radio properties of the cluster.« less

The gamma-ray luminosity function of millisecond pulsars and implications for the GeV excess

DOE PAGES

Hooper, Dan; Mohlabeng, Gopolang

2016-03-29

It has been proposed that a large population of unresolved millisecond pulsars (MSPs) could potentially account for the excess of GeV-scale gamma-rays observed from the region surrounding the Galactic Center. The viability of this scenario depends critically on the gamma-ray luminosity function of this source population, which determines how many MSPs Fermi should have already detected as resolved point sources. In this paper, we revisit the gamma-ray luminosity function of MSPs, without relying on uncertain distance measurements. Our determination, based on a comparison of models with the observed characteristics of the MSP population, suggests that Fermi should have already detectedmore » a significant number of sources associated with such a hypothesized Inner Galaxy population. As a result, we cannot rule out a scenario in which the MSPs residing near the Galactic Center are systematically less luminous than those present in the Galactic Plane or within globular clusters.« less

GABA predicts visual intelligence.

PubMed

Cook, Emily; Hammett, Stephen T; Larsson, Jonas

2016-10-06

Early psychological researchers proposed a link between intelligence and low-level perceptual performance. It was recently suggested that this link is driven by individual variations in the ability to suppress irrelevant information, evidenced by the observation of strong correlations between perceptual surround suppression and cognitive performance. However, the neural mechanisms underlying such a link remain unclear. A candidate mechanism is neural inhibition by gamma-aminobutyric acid (GABA), but direct experimental support for GABA-mediated inhibition underlying suppression is inconsistent. Here we report evidence consistent with a global suppressive mechanism involving GABA underlying the link between sensory performance and intelligence. We measured visual cortical GABA concentration, visuo-spatial intelligence and visual surround suppression in a group of healthy adults. Levels of GABA were strongly predictive of both intelligence and surround suppression, with higher levels of intelligence associated with higher levels of GABA and stronger surround suppression. These results indicate that GABA-mediated neural inhibition may be a key factor determining cognitive performance and suggests a physiological mechanism linking surround suppression and intelligence. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Antagonism Between Luminal and Caffeine, Studied by the Use of Radioisotopes; RECHERCHES SUR LES BARBITURIQUES RADIOACTIFS: LA DISTRIBUTION DU LUMINAL DANS L'ORGANISME ANIMAL EN PRESENCE DE CAFEINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aliprandi, B.; Masironi, R.

1959-10-31

The normal pattern of distribution of luminal in the animal organism was determined in mice using a tracer technique. The effect of an antagonistic drug, e.g., caffeine, on this normal distribution pattern was studied. The results confirmed the hypothesis of the in vivo breaking of the barbituric ring. (J.S.R.)

Estimation of errors in luminance signals encoded by primate retina resulting from sampling of natural images with red and green cones.

PubMed

Osorio, D; Ruderman, D L; Cronin, T W

1998-01-01

Both long-wavelength-sensitive (L) and medium-wavelength-sensitive (M) cones contribute to luminance mechanisms in human vision. This means that luminance and chromatic signals may be confounded. We use power spectra from natural images to estimate the magnitude of the corruption of luminance signals encoded by an array of retinal ganglion cells resembling the primate magnocellular neurons. The magnitude of this corruption is dependent on the cone lattice and is most severe where cones form clumps of a single spectral type. We find that chromatic corruption may equal or exceed the amplitude of other sources of noise and so could impose constraints on visual performance and on eye design.

Distribution and Identification of Luminous Bacteria from the Sargasso Sea

PubMed Central

Orndorff, S. A.; Colwell, R. R.

1980-01-01

Vibrio fischeri and Lucibacterium harveyi constituted 75 of the 83 luminous bacteria isolated from Sargasso Sea surface waters. Photobacterium leiognathi and Photobacterium phosphoreum constituted the remainder of the isolates. Luminescent bacteria were recovered at concentrations of 1 to 63 cells per 100 ml from water samples collected at depths of 160 to 320 m. Two water samples collected at the thermocline yielded larger numbers of viable, aerobic heterotrophic and luminous bacteria. Luminescent bacteria were not recovered from surface microlayer samples. The species distribution of the luminous bacteria reflected previously recognized growth patterns; i.e., L. harveyi and V. fischeri were predominant in the upper, warm waters (only one isolate of P. phosphoreum was obtained from surface tropical waters). PMID:16345575

Monitoring luminous yellow massive stars in M 33: new yellow hypergiant candidates

NASA Astrophysics Data System (ADS)

Kourniotis, M.; Bonanos, A. Z.; Yuan, W.; Macri, L. M.; Garcia-Alvarez, D.; Lee, C.-H.

2017-05-01

Context. The evolution of massive stars surviving the red supergiant (RSG) stage remains unexplored due to the rarity of such objects. The yellow hypergiants (YHGs) appear to be the warm counterparts of post-RSG classes located near the Humphreys-Davidson upper luminosity limit, which are characterized by atmospheric instability and high mass-loss rates. Aims: We aim to increase the number of YHGs in M 33 and thus to contribute to a better understanding of the pre-supernova evolution of massive stars. Methods: Optical spectroscopy of five dust-enshrouded yellow supergiants (YSGs) selected from mid-IR criteria was obtained with the goal of detecting evidence of extensive atmospheres. We also analyzed BVIc photometry for 21 of the most luminous YSGs in M 33 spanning approximately nine years to identify changes in the spectral type that are expected based on the few well-studied YHGs. To explore the properties of circumstellar dust, we performed spectral energy distribution fitting of multi-band photometry of the 21 YSGs. We additionally conducted K-band spectroscopy of the YHG candidate B324 in search of processed ejected material. Results: We find three luminous YSGs in our sample, stars 2, 6 and 13, with log L/L⊙ ≳ 5.35 to be YHG candidates, as they are surrounded by hot dust and are enshrouded within extended, cold dusty envelopes. Our spectroscopy of star 2 shows emission of more than one Hα component, as well as emission of Ca II and [N II], implying an extended atmospheric structure. In addition, the long-term monitoring of the star reveals a dimming in the visual light curve of amplitude larger than 0.5 mag that caused an apparent drop in the temperature that exceeded 500 K. We suggest the observed variability to be analogous to that of the Galactic YHG ρ Cas. We further support the post-RSG classification of N125093 and B324 instead of being LBVs in outburst. Five less luminous YSGs are suggested as post-RSG candidates showing evidence of hot or/and cool dust emission. Conclusions: We demonstrate that mid-IR photometry, combined with optical spectroscopy and time-series photometry, provide a robust method for identifying candidate YHGs. Future discovery of YHGs in Local Group galaxies is critical for the study of the late evolution of intermediate-mass massive stars. Based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio de El Roque de Los Muchachos of the Instituto de Astrofísica de Canarias, on the island of La Palma, and on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/601/A76

Growing massive black holes through supercritical accretion of stellar-mass seeds

NASA Astrophysics Data System (ADS)

Lupi, A.; Haardt, F.; Dotti, M.; Fiacconi, D.; Mayer, L.; Madau, P.

2016-03-01

The rapid assembly of the massive black holes that power the luminous quasars observed at z ˜ 6-7 remains a puzzle. Various direct collapse models have been proposed to head-start black hole growth from initial seeds with masses ˜105 M⊙, which can then reach a billion solar mass while accreting at the Eddington limit. Here, we propose an alternative scenario based on radiatively inefficient supercritical accretion of stellar-mass holes embedded in the gaseous circumnuclear discs (CNDs) expected to exist in the cores of high-redshift galaxies. Our sub-pc resolution hydrodynamical simulations show that stellar-mass holes orbiting within the central 100 pc of the CND bind to very high density gas clumps that arise from the fragmentation of the surrounding gas. Owing to the large reservoir of dense cold gas available, a stellar-mass black hole allowed to grow at super-Eddington rates according to the `slim-disc' solution can increase its mass by three orders of magnitudes within a few million years. These findings are supported by simulations run with two different hydro codes, RAMSES based on the Adaptive Mesh Refinement technique and GIZMO based on a new Lagrangian Godunov-type method, and with similar, but not identical, sub-grid recipes for star formation, supernova feedback, black hole accretion and feedback. The low radiative efficiency of supercritical accretion flows are instrumental to the rapid mass growth of our black holes, as they imply modest radiative heating of the surrounding nuclear environment.

Growth and flagellation of Vibrio fischeri during initiation of the sepiolid squid light organ symbiosis.

PubMed

Ruby, E G; Asato, L M

1993-01-01

A pure culture of the luminous bacterium Vibrio fischeri is maintained in the light-emitting organ of the sepiolid squid Euprymna scolopes. When the juvenile squid emerges from its egg it is symbiont-free and, because bioluminescence is part of an anti-predatory behavior, therefore must obtain a bacterial inoculum from the surrounding environment. We document here the kinetics of the process by which newly hatched juvenile squids become infected by symbiosis-competent V. fischeri. When placed in seawater containing as few as 240 colony-forming-units (CFU) per ml, the juvenile became detectably bioluminescent within a few hours. Colonization of the nascent light organ was initiated with as few as 1 to 10 bacteria, which rapidly began to grow at an exponential rate until they reached a population size of approximately 10(5) cells by 12 h after the initial infection. Subsequently, the number of bacteria in the established symbiosis was maintained essentially constant by a combination of both a > 20-fold reduction in bacterial growth rate, and an expulsion of excess bacteria into the surrounding seawater. While V. fischeri cells are normally flagellated and motile, these bacteria did not elaborate these appendages once the symbiosis was established; however, they quickly began to synthesize flagella when they were removed from the light organ environment. Thus, two important biological characteristics, growth rate and flagellation, were modulated during establishment of the association, perhaps as part of a coordinated series of symbiotic responses.

Lip colour affects perceived sex typicality and attractiveness of human faces.

PubMed

Stephen, Ian D; McKeegan, Angela M

2010-01-01

The luminance contrast between facial features and facial skin is greater in women than in men, and women's use of make-up enhances this contrast. In black-and-white photographs, increased luminance contrast enhances femininity and attractiveness in women's faces, but reduces masculinity and attractiveness in men's faces. In Caucasians, much of the contrast between the lips and facial skin is in redness. Red lips have been considered attractive in women in geographically and temporally diverse cultures, possibly because they mimic vasodilation associated with sexual arousal. Here, we investigate the effects of lip luminance and colour contrast on the attractiveness and sex typicality (masculinity/femininity) of human faces. In a Caucasian sample, we allowed participants to manipulate the colour of the lips in colour-calibrated face photographs along CIELab L* (light--dark), a* (red--green), and b* (yellow--blue) axes to enhance apparent attractiveness and sex typicality. Participants increased redness contrast to enhance femininity and attractiveness of female faces, but reduced redness contrast to enhance masculinity of men's faces. Lip blueness was reduced more in female than male faces. Increased lightness contrast enhanced the attractiveness of both sexes, and had little effect on perceptions of sex typicality. The association between lip colour contrast and attractiveness in women's faces may be attributable to its association with oxygenated blood perfusion indicating oestrogen levels, sexual arousal, and cardiac and respiratory health.

Insulin differentially affects the distribution kinetics of amyloid beta 40 and 42 in plasma and brain.

PubMed

Swaminathan, Suresh Kumar; Ahlschwede, Kristen M; Sarma, Vidur; Curran, Geoffry L; Omtri, Rajesh S; Decklever, Teresa; Lowe, Val J; Poduslo, Joseph F; Kandimalla, Karunya K

2018-05-01

Impaired brain clearance of amyloid-beta peptides (Aβ) 40 and 42 across the blood-brain barrier (BBB) is believed to be one of the pathways responsible for Alzheimer's disease (AD) pathogenesis. Hyperinsulinemia prevalent in type II diabetes was shown to damage cerebral vasculature and increase Aβ accumulation in AD brain. However, there is no clarity on how aberrations in peripheral insulin levels affect Aβ accumulation in the brain. This study describes, for the first time, an intricate relation between plasma insulin and Aβ transport at the BBB. Upon peripheral insulin administration in wild-type mice: the plasma clearance of Aβ40 increased, but Aβ42 clearance reduced; the plasma-to-brain influx of Aβ40 increased, and that of Aβ42 reduced; and the clearance of intracerebrally injected Aβ40 decreased, whereas Aβ42 clearance increased. In hCMEC/D3 monolayers (in vitro BBB model) exposed to insulin, the luminal uptake and luminal-to-abluminal permeability of Aβ40 increased and that of Aβ42 reduced; the abluminal-to-luminal permeability of Aβ40 decreased, whereas Aβ42 permeability increased. Moreover, Aβ cellular trafficking machinery was altered. In summary, Aβ40 and Aβ42 demonstrated distinct distribution kinetics in plasma and brain compartments, and insulin differentially modulated their distribution. Cerebrovascular disease and metabolic disorders may disrupt this intricate homeostasis and aggravate AD pathology.

Phenyl substitution of cationic bis-cyclometalated iridium(iii) complexes for iTMC-LEECs.

PubMed

Suhr, Kristin J; Bastatas, Lyndon D; Shen, Yulong; Mitchell, Lauren A; Frazier, Gary A; Taylor, David W; Slinker, Jason D; Holliday, Bradley J

2016-11-28

A series of seven cationic bis-cyclometalated iridium(iii) complexes of the form [(C^N) 2 (N^N)Ir][PF 6 ] has been designed in order to examine the effect of bulky, hydrophobic phenyl substituents on the structure-property relationship of these ionic transition metal complexes (iTMCs) in light-emitting electrochemical cells (LEECs). Capping phenyl substituents on the cyclometalating and ancillary ligands allows for individual tuning of the HOMO and LUMO energy levels, respectively, yielding an emission range from yellow to red. The complexes in this series exhibit increased quantum yields, up to 70% higher than the unoptimized, archetypal [(2-phenylpyridine) 2 (2,2'-bipyridine)Ir][PF 6 ]. Among these, one complex, C3, was recently reported to produce devices with superior luminance and efficiency. Simultaneous measure of the series of complexes enabled the clear discernment of trends in device performance connected to fundamental structure-property relationships that elucidate the origin of enhanced luminance. In general, phenyl substitution of the 2-phenylpyridine ligands of the parent complex produced higher luminance and faster device response than phenyl substitution of the 2,2'-bipyridine ligand. Overall, complex design and device engineering produce competitive LEECs from simple, single-layer architectures. The synthesis, crystallographic, photophysical, and electrochemical properties of the iTMCs, along with the electroluminescence properties of the LEEC devices are reported herein.

Comparative analysis of water quality and toxicity assessment methods for urban highway runoff.

PubMed

Chen, Rui-Hong; Li, Fei-Peng; Zhang, Hai-Ping; Jiang, Yue; Mao, Ling-Chen; Wu, Ling-Ling; Chen, Ling

2016-05-15

In this study, comparative analyses of highway runoff samples obtained from seventeen storm events have been conducted between the traditional water quality assessment method and biotoxicity tests, using zebrafish (Danio rerio) embryos and luminous bacteria (Vibrio qinghaiensis. Q67) to provide useful information for ecotoxicity assessment of urban highway runoff. The study results showed that the Nemerow pollution index based on US EPA recommended Criteria Maximum Concentrations (CMC) (as traditional water quality assessment method) had no significant correlation with luminous bacteria acute toxicity test results, while significant correlation has been observed with two indicators of 72 hpf (hours post fertilization) hour hatching rate and 96 hpf abnormality rate from the toxicity test with zebrafish embryos. It is therefore concluded that the level of mixture toxicity of highway runoff could not be adequately measured by the Nemerow assessment method. Moreover, the key pollutants identified from the water quality assessment and from the biotoxicity evaluation were not consistent. For biotoxic effect evaluation of highway runoff, three indexes were found to be sensitive, i.e. 24 hpf lethality and 96 hpf abnormality of zebrafish embryos, as well as the inhibition rate for luminous bacteria Q67. It is therefore recommended that these indexes could be incorporated into the traditional Nemerow method to provide a more reasonable evaluation of the highway runoff quality and ecotoxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

Acute and chronic exposure of rat intestinal mucosa to dextran promotes SGLTI-mediated glucose transport.

PubMed

Debnam, E S; Denholm, E E; Grimble, G K

1998-08-01

The intestinal handling of dextran, an alpha-1,6-linked glucose polymer, is poor compared with starch, and some ingested dextran might therefore reach the lower small intestine. As luminal sugar up-regulates SGLT1 (sodium-dependent glucose transporter) locally, we report the effects of a dextran-enriched diet on jejunal and ileal brush border membrane (BBM) glucose uptake. Rats were maintained on a diet containing 65% maltodextrin or 32.5% maltodextrin + 32.5% dextran (10 kD or 40 kD) for 8-10 days, and the kinetics of phlorizin-sensitive [3H]-glucose uptake by purified BBM vesicles was determined. Ingestion of 40-kD but not 10-kD dextran increased Vmax for jejunal and ileal glucose uptake (+64.3% and +61.8% respectively, both P < 0.02). The transport response to 40-kD dextran was in keeping with lower levels of expired H2 at the end of the feeding period. High-performance liquid chromatography (HPLC) analysis of luminal contents indicated extensive hydrolysis of ingested dextran. Finally, 3-h jejunal exposure to 40-kD dextran in vivo increased the Vmax for glucose uptake by jejunal BBM. It is likely that increased SGLT1-mediated glucose uptake after short or longer term mucosal exposure to dextran results from luminal dextran per se or a hydrolysis product. The clinical implications of this up-regulation are discussed.

Effect of fixation positions on perception of lightness

NASA Astrophysics Data System (ADS)

Toscani, Matteo; Valsecchi, Matteo; Gegenfurtner, Karl R.

2015-03-01

Visual acuity, luminance sensitivity, contrast sensitivity, and color sensitivity are maximal in the fovea and decrease with retinal eccentricity. Therefore every scene is perceived by integrating the small, high resolution samples collected by moving the eyes around. Moreover, when viewing ambiguous figures the fixated position influences the dominance of the possible percepts. Therefore fixations could serve as a selection mechanism whose function is not confined to finely resolve the selected detail of the scene. Here this hypothesis is tested in the lightness perception domain. In a first series of experiments we demonstrated that when observers matched the color of natural objects they based their lightness judgments on objects' brightest parts. During this task the observers tended to fixate points with above average luminance, suggesting a relationship between perception and fixations that we causally proved using a gaze contingent display in a subsequent experiment. Simulations with rendered physical lighting show that higher values in an object's luminance distribution are particularly informative about reflectance. In a second series of experiments we considered a high level strategy that the visual system uses to segment the visual scene in a layered representation. We demonstrated that eye movement sampling mediates between the layer segregation and its effects on lightness perception. Together these studies show that eye fixations are partially responsible for the selection of information from a scene that allows the visual system to estimate the reflectance of a surface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Truong, Pauline T., E-mail: ptruong@bccancer.bc.ca; Breast Cancer Outcomes Unit, British Columbia Cancer Agency, Vancouver Island Centre, University of British Columbia, Victoria, BC; Sadek, Betro T.

Purpose: To examine locoregional and distant recurrence (LRR and DR) in women with pT1-2N0 breast cancer according to approximated subtype and clinicopathologic characteristics. Methods and Materials: Two independent datasets were pooled and analyzed. The study participants were 1994 patients with pT1-2N0M0 breast cancer, treated with mastectomy without radiation therapy. The patients were classified into 1 of 5 subtypes: luminal A (ER+ or PR+/HER 2−/grade 1-2, n=1202); luminal B (ER+ or PR+/HER 2−/grade 3, n=294); luminal HER 2 (ER+ or PR+/HER 2+, n=221); HER 2 (ER−/PR−/HER 2+, n=105) and triple-negative breast cancer (TNBC) (ER−/PR−/HER 2−, n=172). Results: The median follow-up timemore » was 4.3 years. The 5-year Kaplan-Meier (KM) LRR were 1.8% in luminal A, 3.1% in luminal B, 1.7% in luminal HER 2, 1.9% in HER 2, and 1.9% in TNBC cohorts (P=.81). The 5-year KM DR was highest among women with TNBC: 1.8% in luminal A, 5.0% in luminal B, 2.4% in luminal HER 2, 1.1% in HER 2, and 9.6% in TNBC cohorts (P<.001). Among 172 women with TNBC, the 5-year KM LRR were 1.3% with clear margins versus 12.5% with close or positive margins (P=.04). On multivariable analysis, factors that conferred higher LRR risk were tumors >2 cm, lobular histology, and close/positive surgical margins. Conclusions: The 5-year risk of LRR in our pT1-2N0 cohort treated with mastectomy was generally low, with no significant differences observed between approximated subtypes. Among the subtypes, TNBC conferred the highest risk of DR and an elevated risk of LRR in the presence of positive or close margins. Our data suggest that although subtype alone cannot be used as the sole criterion to offer postmastectomy radiation therapy, it may reasonably be considered in conjunction with other clinicopathologic factors including tumor size, histology, and margin status. Larger cohorts and longer follow-up times are needed to define which women with node-negative disease have high postmastectomy LRR risks in contemporary practice.« less

The large area KX quasar catalogue - I. Analysis of the photometric redshift selection and the complete quasar catalogue

NASA Astrophysics Data System (ADS)

Maddox, Natasha; Hewett, Paul C.; Péroux, Céline; Nestor, Daniel B.; Wisotzki, Lutz

2012-08-01

The results of a large area, ˜600 deg2, K-band flux-limited spectroscopic survey for luminous quasars are presented. The survey utilizes the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) in regions of sky within the Sloan Digital Sky Survey (SDSS) footprint. The K-band excess (KX) of all quasars with respect to Galactic stars is exploited in combination with a photometric redshift/classification scheme to identify quasar candidates for spectroscopic follow-up observations. The data contained within this investigation will be able to provide new constraints on the fraction of luminous quasars reddened by dust with E(B - V) ≤ 0.5 mag. The spectroscopic sample is defined using the K-band, 14.0 ≤ K ≤ 16.6, and SDSS i-band limits of i = 19.5, 19.7 and 22.0 over sky areas of 287, 150 and 196 deg2, respectively. The survey includes >3200 known quasars from the SDSS and more than 250 additional confirmed quasars from the KX selection. A well-defined subsample of quasars in the redshift interval 1.0 ≤ z ≤ 3.5 includes 1152 objects from the SDSS and 172 additional KX-selected quasars. The quasar selection is >95 per cent complete with respect to known SDSS quasars and >95 per cent efficient, largely independent of redshift and i-band magnitude. The properties of the new KX-selected quasars confirm the known redshift-dependent effectiveness of the SDSS quasar selection and provide a sample of luminous quasars experiencing intermediate levels of extinction by dust. The catalogue represents an important step towards the assembly of a well-defined sample of luminous quasars that may be used to investigate the properties of quasars experiencing intermediate levels of dust extinction within their host galaxies or due intervening absorption line systems. †Based on observations made with ESO telescopes at the La Silla Paranal Observatory under programme IDs 083.A0360 and 085.A0359.‡Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).

Flame and Soot Boundaries of Laminar Jet Diffusion Flames. Appendix A

NASA Technical Reports Server (NTRS)

Xu, F.; Dai, Z.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

2002-01-01

The shapes (flame-sheet and luminous-flame boundaries) or steady weakly buoyant round hydrocarbon-fueled laminar-jet diffusion flames in still and coflowing air were studied both experimentally and theoretically. Flame-sheet shapes were measured from photographs using a CH optical filter to distinguish flame-sheet boundaries in the presence of blue CO2 and OH emissions and yellow continuum radiation from soot. Present experimental conditions included acetylene-, methane-, propane-, and ethylene-fueled flames having initial reactant temperatures of 300 K. ambient pressures of 4-50 kPa, jet-exit Reynolds numbers of 3-54, initial air/fuel velocity ratios of 0-9, and luminous flame lengths of 5-55 mm; earlier measurements for propylene- and 1,3-butadiene-fueled flames for similar conditions were considered as well. Nonbuoyant flames in still air were observed at microgravity conditions; essentially nonbuoyant flames in coflowing air were observed at small pressures to control effects of buoyancy. Predictions of luminous flame boundaries from soot luminosity were limited to laminar smoke-point conditions, whereas predictions of flame-sheet boundaries ranged from soot-free to smoke-point conditions. Flame-shape predictions were based on simplified analyses using the boundary-layer approximations along with empirical parameters to distinguish flame-sheet and luminous-flame (at the laminar smoke point) boundaries. The comparison between measurements and predictions was remarkably good and showed that both flame-sheet and luminous-flame lengths are primarily controlled by fuel flow rates with lengths in coflowing air approaching 2/3 of the lengths in still air as coflowing air velocities are increased. Finally, luminous flame lengths at laminar smoke-point conditions were roughly twice as long as flame-sheet lengths at comparable conditions because of the presence of luminous soot particles in the fuel-lean region of the flames.

Luminal glucose concentrations in the gut under normal conditions.

PubMed

Ferraris, R P; Yasharpour, S; Lloyd, K C; Mirzayan, R; Diamond, J M

1990-11-01

Luminal glucose (Glc) concentrations in the small intestine (SI) are widely assumed to be 50-500 mM. These values have posed problems for interpreting SI luminal osmolality and absorptive capacity, Glc transporter Michaelis-Menten constants (Km), and the physiological role of active Glc transport and its regulation. Hence we measured luminal contents, osmolality, and Glc, Na+, and K+ concentrations in normally feeding rats, rabbits, and dogs. Measured Glc concentrations were compatible with the portion of measured osmolality not accounted for by Na+ and K+ salts, amino acids, and peptides. Mean SI luminal osmolalities were less than or equal to 100 mosmol/kg hypertonic. For animals on the most nearly physiological diets, SI Glc concentrations averaged 0.4-24 mM and ranged with time and SI region from 0.2 to a maximum of 48 mM. The older published very high values are artifacts of direct infusion of concentrated Glc solutions into the gut, nonspecific Glc assays, and failure to test for quantitative recovery or to centrifuge samples in the cold. By storing food after meals and releasing it between meals, rat stomach greatly damps diurnal fluctuations in quantity and osmolality of food reaching the SI and hence also damps fluctuations in absorption rates. These new values for luminal Glc have five important physiological implications: the problem of accounting for apparently very hypertonic SI contents in the face of high osmotic water permeability disappears; the effective Km of the SI Glc transporter is now comparable to prevailing Glc concentrations; the SI no longer appears to have enormous excess absorptive capacity for Glc; regulation of Glc transport by dietary intake now makes functional sense; and the claim that high luminal Glc concentrations permit solvent drag to become the major mode of Glc absorption under normal conditions is undermined.

The selective cyclooxygenase-2 inhibitor parecoxib markedly improves the ability of the duodenum to regulate luminal hypertonicity in anaesthetized rats.

PubMed

Sedin, J; Sjöblom, M; Nylander, O

2012-07-01

To examine whether the prevention of post-operative duodenal ileus by treatment with parecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, affects the ability of the duodenum to respond to luminal hypertonicity. The proximal duodenums of anaesthetized rats were perfused with hypertonic NaCl solutions with osmolalities of 400, 500, 600 or 700 mOsm kg(-1) , and the effects on mucosal permeability, motility, transepithelial net fluid flux and effluent osmolality were assessed in the absence (control) and presence of parecoxib. Parecoxib-treated, but not control animals, exhibited duodenal contractions, which were reduced by the nicotinic receptor antagonists mecamylamine and hexamethonium and by perfusion with 700 mOsm kg(-1) . All animals responded to luminal hypertonicity with induction of net fluid secretion, which peaked at an osmolality of 500 mOsm kg(-1) . The hypertonicity-induced increases in fluid secretion were twofold greater in parecoxib-treated than in control rats and attenuated by nicotinic receptor blockade. The decrease in luminal osmolality correlated with the osmolality of the perfusion solution in both control and parecoxib-treated animals but the osmolality-adjusting capability was markedly better in the latter group. Rats exposed to duodenal luminal distension responded to hypertonicity with a greater fluid secretion and a larger decrease in luminal osmolality than control rats. Perfusion with 700 mOsm kg(-1) increased mucosal permeability in parecoxib-treated animals only, an effect abolished by nicotinic receptor blockade. Parecoxib markedly improved the ability of the duodenum to sense and to decrease luminal hypertonicity by a mechanism most probably involving inhibition of COX-2 and stimulation of nicotinic acetylcholine receptors. © 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.