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Sample records for light attenuation caused

  1. Triptans attenuate circadian responses to light.

    PubMed

    Basu, Priyoneel; Ie, Naomi; Wensel, Adrienne L; Baskerville, Joelle D; Smith, Victoria M; Antle, Michael C

    2015-10-01

    Daily exposure to light synchronizes the circadian clock, located in the suprachiasmatic nucleus (SCN), to external day/night cycles. These responses to light can be modified by serotonergic drugs, such as serotonin 5HT1B receptor agonists. Triptans are specific 5HT1B agonists prescribed to treat migraines. Here, we examined the effects of two triptans (zolmitriptan and sumatriptan) on photic phase resetting in Syrian hamsters. Pre-treatment with intra-SCN sumatriptan significantly attenuates, and at higher doses completely blocks, phase advances to light during the late night. Pre-treatment with systemic zolmitriptan significantly attenuates both light-induced phase advances and phase delays. Neither of these drugs, nor their vehicles, causes phase shifts on their own. Pre-treatment with zolmitriptan also significantly reduces the expression of light-induced c-fos in the SCN. Neither zolmitriptan nor vehicle alone induces significant c-fos expression in the SCN. Finally, pre-treatment with zolmitriptan does not attenuate phase shifts to intra-SCN N-methyl-d-aspartate injections, indicating that the mechanism of action for zolmitriptan is likely to be through activation of presynaptic 5HT1B receptors on retinal terminals, thereby decreasing light-induced neurotransmitter release. As triptans are commercially available medications, there is potential for their use in blocking unwanted photic phase shifting during shift-work or jet-lag. Additionally, triptans may also affect the circadian clock in patients receiving them regularly for migraines. Finally, our results may hint at the mechanism by which triptans can alleviate the photophobia that frequently accompanies migraines, namely by activating 5HT1B receptors on retinal terminals elsewhere in the brain, and thereby diminishing visually-evoked neurotransmitter signalling in those areas.

  2. Light attenuation in estuarine mangrove lakes

    NASA Astrophysics Data System (ADS)

    Frankovich, Thomas A.; Rudnick, David T.; Fourqurean, James W.

    2017-01-01

    Submerged aquatic vegetation (SAV) cover has declined in brackish lakes in the southern Everglades characterized by low water transparencies, emphasizing the need to evaluate the suitability of the aquatic medium for SAV growth and to identify the light attenuating components that contribute most to light attenuation. Underwater attenuation of downwards irradiance of photosynthetically active radiation (PAR) was determined over a three year period at 42 sites in shallow (<2 m depth) mangrove-surrounded lakes in two sub-estuaries in the coastal Everglades, Florida USA. Turbidity, chromophoric dissolved organic matter (CDOM), and phytoplankton chlorophyll a (chl a) were measured concurrently and their respective contributions to the light attenuation rate were estimated. Light transmission to the benthos relative to literature estimates of minimum requirements for SAV growth indicated that the underwater light environment was often unsuitable for SAV. Light attenuation rates (n = 417) corrected for solar elevation angles ranged from 0.16 m-1 to 9.83 m-1 with a mean of 1.73 m-1. High concentrations of CDOM with high specific light absorption contributed the most to light attenuation followed by turbidity and chl a. CDOM alone sufficiently reduces light transmission beyond the estimated limits for SAV growth, making it difficult for ecosystem managers to increase SAV abundance by management activities. Light limitation of SAV in these areas may be a persistent feature because of their proximity to CDOM source materials from the surrounding mangrove swamp. Increasing freshwater flow into these areas may dilute CDOM concentrations and improve the salinity and light climate for SAV communities.

  3. Orally administered epigallocatechin gallate attenuates light-induced photoreceptor damage.

    PubMed

    Costa, Belmira Lara da Silveira Andrade da; Fawcett, Rebecca; Li, Guang-Yu; Safa, Rukhsana; Osborne, Neville N

    2008-07-01

    EGCG, a major component of green tea, has a number of properties which includes it being a powerful antioxidant. The purpose of this investigation was to deduce whether inclusion of EGCG in the drinking water of albino rats attenuates the effect of a light insult (2200lx, for 24h) to the retina. TUNEL-positive cells were detected in the outer nuclear layer of the retina, indicating the efficacy of the light insult in inducing photoreceptor degeneration. Moreover, Ret-P1 and the mRNA for rhodopsin located at photoreceptors were also significantly reduced as well as the amplitude of both the a- and b-waves of the electroretinogram was also reduced showing that photoreceptors in particular are affected by light. An increase in protein/mRNA of GFAP located primarily to Müller cells caused by light shows that other retinal components are also influenced by the light insult. However, antigens associated with bipolar (alpha-PKC), ganglion (Thy-1) and amacrine (GABA) cells, in contrast, appeared unaffected. The light insult also caused a change in the content of various proteins (caspase-3, caspase-8, PARP, Bad, and Bcl-2) involved in apoptosis. A number of the changes to the retina caused by a light insult were significantly attenuated when EGCG was in the drinking water. The reduction of the a- and b-waves and photoreceptor specific mRNAs/protein caused by light were significantly less. In addition, EGCG attenuated the changes caused by light to certain apoptotic proteins (especially at after 2 days) but did not appear to significantly influence the light-induced up-regulation of GFAP protein/mRNA. It is concluded that orally administered EGCG blunts the detrimental effect of light to the retina of albino rats where the photoreceptors are primarily affected.

  4. Engineering a Light-Attenuating Artificial Iris

    PubMed Central

    Shareef, Farah J.; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-01-01

    Purpose Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. Methods The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Results Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Conclusions Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage. PMID:27116547

  5. Bubbles cause seismic wave attenuation: Laboratory measurements and numerical simulations

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Quintal, Beatriz; Chapman, Samuel; Podladchikov, Yury; Grasselli, Giovanni; Burg, Jean-Pierre

    2015-04-01

    Seismic wave attenuation (1/Q) is a key to uncover the saturation and, in general, to improve the monitoring and surveying of subsurface domains. Nevertheless, how fluids that saturate rocks absorb elastic energy (i.e. cause 1/Q) is still poorly understood, studied and incorporated in geophysical methods. One of the invoked mechanisms, wave induced fluid flow (WIFF), is reputed to cause significant attenuation. This mechanism is governed by the flow of viscous fluids into a porous rock, and causes attenuation as a function of the fluid diffusivity [m2/s] and the pressure gradient [Pa/m], which is generated by the propagation of the elastic wave. However, some published, and newly acquired laboratory data-sets reporting 1/Q in almost fully saturated sandstones are difficult to explain with WIFF theories as they are frequency-dependent and have maximum of attenuation at frequencies

  6. NAD+ maintenance attenuates light induced photoreceptor degeneration Δ

    PubMed Central

    Bai, Shi; Sheline, Christian T.

    2013-01-01

    Light-induced retinal damage (LD) occurs after surgery or sun exposure. We previously showed that zinc (Zn2+) accumulated in photoreceptors and RPE cells after LD but prior to cell death, and pyruvate or nicotinamide attenuated the resultant death perhaps by restoring nicotinamide adenine dinucleotide (NAD+) levels. We first examined the levels of NAD+ and the efficacy of pyruvate or nicotinamide in oxidative toxicities using primary retinal cultures. We next manipulated NAD+ levels in vivo and tested the affect on LD to photoreceptors and RPE. NAD+ levels cycle with a 24-h rhythm in mammals, which is affected by the feeding schedule. Therefore, we tested the affect of increasing NAD+ levels on LD by giving nicotinamide, inverting the feeding schedule, or using transgenic mice which overexpress cytoplasmic nicotinamide mononucleotide adenyl-transferase-1 (cytNMNAT1), an NAD+ synthetic enzyme. Zn2+ accumulation was also assessed in culture and in retinal sections. Retinas of light damaged animals were examined by OCT and plastic sectioning, and retinal NAD levels were measured. Day fed, or nicotinamide treated rats showed less NAD+ loss, and LD compared to night fed rats or untreated rats without changing the Zn2+ staining pattern. CytNMNAT1 showed less Zn2+ staining, NAD+ loss, and cell death after LD. In conclusion, intense light, Zn2+ and oxidative toxicities caused an increase in Zn2+, NAD+ loss, and cell death which were attenuated by NAD+ restoration. Therefore, NAD+ levels play a protective role in LD-induced death of photoreceptors and RPE cells. PMID:23274583

  7. Effects of light attenuation on the sponge holobiont- implications for dredging management

    NASA Astrophysics Data System (ADS)

    Pineda, Mari-Carmen; Strehlow, Brian; Duckworth, Alan; Doyle, Jason; Jones, Ross; Webster, Nicole S.

    2016-12-01

    Dredging and natural sediment resuspension events can cause high levels of turbidity, reducing the amount of light available for photosynthetic benthic biota. To determine how marine sponges respond to light attenuation, five species were experimentally exposed to a range of light treatments. Tolerance thresholds and capacity for recovery varied markedly amongst species. Whilst light attenuation had no effect on the heterotrophic species Stylissa flabelliformis and Ianthella basta, the phototrophic species Cliona orientalis and Carteriospongia foliascens discoloured (bleached) over a 28 day exposure period to very low light (<0.8 mol photons m‑2 d‑1). In darkness, both species discoloured within a few days, concomitant with reduced fluorescence yields, chlorophyll concentrations and shifts in their associated microbiomes. The phototrophic species Cymbastela coralliophila was less impacted by light reduction. C. orientalis and C. coralliophila exhibited full recovery under normal light conditions, whilst C. foliascens did not recover and showed high levels of mortality. The light treatments used in the study are directly relevant to conditions that can occur in situ during dredging projects, indicating that light attenuation poses a risk to photosynthetic marine sponges. Examining benthic light levels over temporal scales would enable dredging proponents to be aware of conditions that could impact on sponge physiology.

  8. Effects of light attenuation on the sponge holobiont- implications for dredging management

    PubMed Central

    Pineda, Mari-Carmen; Strehlow, Brian; Duckworth, Alan; Doyle, Jason; Jones, Ross; Webster, Nicole S.

    2016-01-01

    Dredging and natural sediment resuspension events can cause high levels of turbidity, reducing the amount of light available for photosynthetic benthic biota. To determine how marine sponges respond to light attenuation, five species were experimentally exposed to a range of light treatments. Tolerance thresholds and capacity for recovery varied markedly amongst species. Whilst light attenuation had no effect on the heterotrophic species Stylissa flabelliformis and Ianthella basta, the phototrophic species Cliona orientalis and Carteriospongia foliascens discoloured (bleached) over a 28 day exposure period to very low light (<0.8 mol photons m−2 d−1). In darkness, both species discoloured within a few days, concomitant with reduced fluorescence yields, chlorophyll concentrations and shifts in their associated microbiomes. The phototrophic species Cymbastela coralliophila was less impacted by light reduction. C. orientalis and C. coralliophila exhibited full recovery under normal light conditions, whilst C. foliascens did not recover and showed high levels of mortality. The light treatments used in the study are directly relevant to conditions that can occur in situ during dredging projects, indicating that light attenuation poses a risk to photosynthetic marine sponges. Examining benthic light levels over temporal scales would enable dredging proponents to be aware of conditions that could impact on sponge physiology. PMID:27958345

  9. Significant Attenuation of Lightly Damped Resonances Using Particle Dampers

    NASA Technical Reports Server (NTRS)

    Smith, Andrew; LaVerde, Bruce; Hunt, Ron; Knight, Joseph Brent

    2015-01-01

    When equipment designs must perform in a broad band vibration environment it can be difficult to avoid resonances that affect life and performance. This is especially true when an organization seeks to employ an asset from a heritage design in a new, more demanding vibration environment. Particle dampers may be used to provide significant attenuation of lightly damped resonances to assist with such a deployment of assets by including only a very minor set of modifications. This solution may be easier to implement than more traditional attenuation schemes. Furthermore, the cost in additional weight to the equipment can be very small. Complexity may also be kept to a minimum, because the particle dampers do not require tuning. Attenuating the vibratory response with particle dampers may therefore be simpler (in a set it and forget it kind of way) than tuned mass dampers. The paper will illustrate the use of an "equivalent resonance test jig" that can assist designers in verifying the potential resonance attenuation that may be available to them during the early trade stages of the design. An approach is suggested for transforming observed attenuation in the jig to estimated performance in the actual service design. KEY WORDS: Particle Damper, Performance in Vibration Environment, Damping, Resonance, Attenuation, Mitigation of Vibration Response, Response Estimate, Response Verification.

  10. Light sheet microscopy reveals more gradual light attenuation in light green versus dark green soybean leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Light wavelengths preferentially absorbed by chlorophyll (chl) often display steep absorption gradients. This oversaturates photosynthesis in upper chloroplasts and deprives lower chloroplasts of blue and red light, causing a steep gradient in carbon fixation. Reducing chl content could create a mor...

  11. Rosiglitazone attenuates renal injury caused by hyperlipidemic pancreatitis

    PubMed Central

    Wang, Rui; Yan, Zhaopeng; Wu, Xingmao; Ji, Kaiqiang; Wang, Haiyuan; Zang, Bin

    2015-01-01

    Hyperlipidemic pancreatitis (HP) is a serious inflammatory disease with very high mortality and multiple organ injuries including renal injury. Rosiglitazone (Ros), an agonist of peroxisome proliferator activated receptor-γ (PPAR-γ), was reported to show a protective role against pancreatitis. However, whether Ros has an effect on renal injury caused by HP is not yet clear. In the present study, the function of Ros was explored using ELISA, RT-PCR, western blot, PAS staining and immunohistochemistry. Results of this study showed that Ros could inhibit the activation of NF-κB and MAPK P38 signaling pathways, relieve inflammatory response and inhibit cell apoptosis, thus attenuating renal injury caused by HP. This study suggested that Ros might be a promising drug for the treatment of renal injury caused by HP and also laid theoretical foundation for the development of renal injury treatment. PMID:26191125

  12. The relationship between phytoplankton concentration and light attenuation in ocean waters

    NASA Technical Reports Server (NTRS)

    Phinney, David A.; Yentsch, Charles S.

    1986-01-01

    The accuracy of chlorophyll estimates by ocean color algorithms is affected by the variability of particulate attenuation; the presence of dissolved organic matter; and the nonlinear inverse relationship between the attenuation coefficient, K, and chlorophyll. Data collected during the Warm Core Rings Program were used to model the downwelling light field and determine the impact of these errors. A possible mechanism for the nonlinearity of K and chlorophyll is suggested; namely, that changing substrate from nitrate-nitrogen to ammonium causes enhanced blue absorption by photosynthetic phytoplankton in oligotrophic surface waters.

  13. Quantification of light attenuation in optically cleared mouse brains

    PubMed Central

    d’Esposito, Angela; Nikitichev, Daniil; Desjardins, Adrien; Walker-Samuel, Simon; Lythgoe, Mark F.

    2015-01-01

    Optical clearing, in combination with recently developed optical imaging techniques, enables visualization and acquisition of high resolution, three-dimensional images of biological structures deep within tissue. Many different approaches can be used to reduce light absorption and scattering within the tissue, but there is a paucity of research on the quantification of clearing efficacy. With the use of a custom-made spectroscopy system, we developed a way to quantify the quality of clearing in biological tissue, and applied it to the mouse brain. Three clearing techniques were compared: BABB (Murray’s clear), pBABB (a modification of BABB which includes the use of hydrogen peroxide) and passive CLARITY. Despite being limited to autofluorescence studies, we found that pBABB produced the highest degree of optical clearing. Furthermore, the approach allows regional measurement of light attenuation to be performed, and. our results show that light is most attenuated in regions with high lipid content. This work provides a way to choose between the multiple clearing protocols available, and it could prove useful for evaluating images that are acquired with cleared tissues. PMID:26277988

  14. Modeling future scenarios of light attenuation and potential seagrass success in a eutrophic estuary

    USGS Publications Warehouse

    del Barrio, Pilar; Ganju, Neil K.; Aretxabaleta, Alfredo L.; Hayn, Melanie; García, Andrés; Howarth, Robert W.

    2014-01-01

    Estuarine eutrophication has led to numerous ecological changes, including loss of seagrass beds. One potential cause of these losses is a reduction in light availability due to increased attenuation by phytoplankton. Future sea level rise will also tend to reduce light penetration and modify seagrass habitat. In the present study, we integrate a spectral irradiance model into a biogeochemical model coupled to the Regional Ocean Model System (ROMS). It is linked to a bio-optical seagrass model to assess potential seagrass habitat in a eutrophic estuary under future nitrate loading and sea-level rise scenarios. The model was applied to West Falmouth Harbor, a shallow estuary located on Cape Cod (Massachusetts) where nitrate from groundwater has led to eutrophication and seagrass loss in landward portions of the estuary. Measurements of chlorophyll, turbidity, light attenuation, and seagrass coverage were used to assess the model accuracy. Mean chlorophyll based on uncalibrated in-situ fluorometry varied from 28 μg L−1 at the landward-most site to 6.5 μg L−1 at the seaward site, while light attenuation ranged from 0.86 to 0.45 m-1. The model reproduced the spatial variability in chlorophyll and light attenuation with RMS errors of 3.72 μg L−1 and 0.07 m-1 respectively. Scenarios of future nitrate reduction and sea-level rise suggest an improvement in light climate in the landward basin with a 75% reduction in nitrate loading. This coupled model may be useful to assess habitat availability changes due to eutrophication and sediment resuspension and fully considers spatial variability on the tidal timescale.

  15. Blast wave attenuation by lightly destructable granular materials

    NASA Astrophysics Data System (ADS)

    Golub, V. V.; Lu, F. K.; Medin, S. A.; Mirova, O. A.; Parshikov, A. N.; Petukhov, V. A.; Volodin, V. V.

    Terrorist bombings are a dismal reality nowadays. One of the most effective ways for protection against blast overpressure is the use of lightly compacted materials such as sand [1] and aqueous foam [2] as a protective envelope or barrier. According to [1], shock wave attenuation in a mine tunnel (one-dimensional case) behind a destroyed object is given by q_e ≈ q {1}/{1 + 4(S/q)^{1/6} bρ _{mat} /L^{1/3} }where qe — effective charge, S — exposed area of the obstacle, q — TNT equivalent (grams), L — distance between charge and obstacle, b — obstacle thickness and ρ mat — material density. This empirical equation is applicable only in a one-dimensional case but not for a less confined environment. Another way of protecting a structure against blast is to coat the surface with a sacrificial layer. In [3] full-scale experiments were carried out to investigate the behaviour of a covering of aluminum foam under the effect of a blast wave.

  16. Physical and biogeochemical controls on light attenuation in a eutrophic, back-barrier estuary

    USGS Publications Warehouse

    Ganju, Neil K.; Miselis, Jennifer L.; Aretxabaleta, Alfredo L.

    2014-01-01

    Light attenuation is a critical parameter governing the ecological function of shallow estuaries. In these systems primary production is often dominated by benthic macroalgae and seagrass; thus light penetration to the bed is of primary importance. We quantified light attenuation in three seagrass meadows in Barnegat Bay, New Jersey, a shallow eutrophic back-barrier estuary; two of the sites were located within designated Ecologically Sensitive Areas (ESAs). We sequentially deployed instrumentation measuring photosynthetically active radiation, chlorophyll-a (chl-a) fluorescence, dissolved organic matter fluorescence (fDOM; a proxy for colored DOM absorbance), turbidity, pressure, and water velocity at 10 min intervals over three week periods at each site. At the southernmost site, where sediment availability was highest, light attenuation was highest and dominated by turbidity and to a lesser extent chl-a and CDOM. At the central site, chl-a dominated followed by turbidity and CDOM, and at the northernmost site turbidity and CDOM contributed equally to light attenuation. At a given site, the temporal variability of light attenuation exceeded the difference in median light attenuation at the three sites, indicating the need for continuous high-temporal resolution measurements. Vessel wakes, anecdotally implicated in increasing sediment resuspension, did not contribute to local resuspension within the seagrass beds, though frequent vessel wakes were observed in the channels. With regards to light attenuation and water clarity, physical and biogeochemical variables appear to outweigh any regulation of boat traffic within the ESAs.

  17. Light sheet microscopy reveals more gradual light attenuation in light-green versus dark-green soybean leaves

    PubMed Central

    Slattery, Rebecca A.; Grennan, Aleel K.; Sivaguru, Mayandi; Sozzani, Rosangela; Ort, Donald R.

    2016-01-01

    Light wavelengths preferentially absorbed by chlorophyll (chl) often display steep absorption gradients. This over-saturates photosynthesis in upper chloroplasts and deprives lower chloroplasts of blue and red light. Reducing chl content could create a more even leaf light distribution and thereby increase leaf light-use efficiency and overall canopy photosynthesis. This was tested on soybean cultivar ‘Clark’ (WT) and a near-isogenic chl b deficient mutant, Y11y11, grown in controlled environment chambers and in the field. Light attenuation was quantified using a novel approach involving light sheet microscopy. Leaf adaxial and abaxial surfaces were illuminated separately with blue, red, and green wavelengths, and chl fluorescence was detected orthogonally to the illumination plane. Relative fluorescence was significantly greater in deeper layers of the Y11y11 mesophyll than in WT, with the greatest differences in blue, then red, and finally green light when illuminated from the adaxial surface. Modeled relative photosynthesis based on chlorophyll profiles and Beer’s Law predicted less steep gradients in mutant relative photosynthesis rates compared to WT. Although photosynthetic light-use efficiency was greater in the field-grown mutant with ~50% lower chl, light-use efficiency was lower in the mutant when grown in chambers where chl was ~80% reduced. This difference is probably due to pleiotropic effects of the mutation that accompany very severe reductions in chlorophyll and may warrant further testing in other low-chl lines. PMID:27329746

  18. Star Formation History, Dust Attenuation, and Extragalactic Background Light

    NASA Astrophysics Data System (ADS)

    Khaire, Vikram; Srianand, Raghunathan

    2015-05-01

    At any given epoch, the extragalactic background light (EBL) carries imprints of integrated star formation activities in the universe until that epoch. On the other hand, in order to estimate the EBL when direct observations are not possible, one requires an accurate estimation of the star formation rate density (SFRD) and the dust attenuation ({{A}ν }) in galaxies. Here, we present a “progressive fitting method” that determines the global average SFRD(z) and {{A}ν }(z) for any given extinction curve by using the available multiwavelength, multiepoch galaxy luminosity function measurements. Using the available observations, we determine the best-fit combinations of SFRD(z) and {{A}ν }(z), in a simple fitting form, up to z∼ 8 for five well-known extinction curves. We find, irrespective of the extinction curve used, the z at which the SFRD(z) peaks is higher than the z above which {{A}ν }(z) begins to decline. For each case, we compute the EBL from ultraviolet to the far-infrared regime and the optical depth ({{τ }γ }) encountered by the high-energy γ-rays due to pair production upon collisions with these EBL photons. We compare these with measurements of the local EBL, γ-ray horizon, and {{τ }γ } measurements using Fermi-Large Area Telescope. All these and the comparison of independent SFRD(z) and {{A}ν }(z) measurements from the literature with our predictions favor an extinction curve similar to that of the Large Magellanic Cloud Supershell.

  19. A field theoretical restoration method for images degraded by non-uniform light attenuation : an application for light microscopy.

    PubMed

    Lee, Hwee Kuan; Uddin, Mohammad Shorif; Sankaran, Shvetha; Hariharan, Srivats; Ahmed, Sohail

    2009-07-06

    Microscopy has become a de facto tool for biology. However, it suffers from a fundamental problem of poor contrast with increasing depth, as the illuminating light gets attenuated and scattered and hence can not penetrate through thick samples. The resulting decay of light intensity due to attenuation and scattering varies exponentially across the image. The classical space invariant deconvolution approaches alone are not suitable for the restoration of uneven illumination in microscopy images. In this paper, we present a novel physics-based field theoretical approach to solve the contrast degradation problem of light microscopy images. We have confirmed the effectiveness of our technique through simulations as well as through real field experimentations.

  20. Light attenuation and submersed macrophyte distribution in the tidal Potomac River and estuary

    USGS Publications Warehouse

    Carter, V.; Rybicki, N.B.

    1990-01-01

    Changing light availability may be responsible for the discontinuous distribution of submersed aquatic macrophytes in the freshwater tidal Potomac River. During the 1985-1986 growing seasons, light attenuation and chlorophyll a and suspended particulate material concentrations were measured in an unvegetated reach (B) and in two adjacent vegetated reaches (A and C). Light attenuation in reach B (the lower, fresh to oligohaline tidal river) was greater than that in reach A (the recently revegetated, upper, freshwater tidal river) in both years. Reach B light attenuation was greater than that in reach C (the vegetated, oligohaline to mesohaline transition zone of the Potomac Estuary) in 1985 and similar to that in reach C in 1986. In reach B, 5% of total below-surface light penetrated only an average of 1.3 m in 1985 and 1.0m in 1986, compared with 1.9 m and 1.4 m in reach A in 1985 and 1986, respectively. Water column chlorophyll a concentration controlled light availability in reaches A and B in 1985, whereas both chlorophyll a and suspended particulate material concentrations were highly correlated with attenuation in both reaches in 1986. Reach C light attenuation was correlated with suspended particulate material in 1986. The relationship between attenuation coefficient and Secchi depth was KPAR=1.38/Secchi depth. The spectral distribution of light at 1 m was shifted toward the red portion of the visible spectrum compared to surface light. Blue light was virtually absent at 1.0 m in reach B during July and August 1986. Tidal range is probably an important factor in determining light availability for submersed macrophyte propagule survival at the sediment-water interface in this shallow turbid system. ?? 1990 Estuarine Research Federation.

  1. Estimation of diffuse attenuation of ultraviolet light in optically shallow Florida Keys waters from MODIS measurements

    EPA Science Inventory

    Diffuse attenuation of solar light (Kd, m−1) determines the percentage of light penetrating the water column and available for benthic organisms. Therefore, Kd can be used as an index of water quality for coastal ecosystems that are dependent on photosynthesis, such as the coral ...

  2. Acoustical Scattering, Propagation, and Attenuation Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake

    DTIC Science & Technology

    2011-09-30

    Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake Kelly J. Benoit-Bird College of Oceanic and Atmospheric Sciences 104...Attenuation Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...have successfully recruited graduate students that will conduct thesis research as part of this project. RESULTS Both hake and Humboldt squid

  3. Light attenuation - a more effective basis for the management of fine suspended sediment than mass concentration?

    PubMed

    Davies-Colley, Robert J; Ballantine, Deborah J; Elliott, Sandy H; Swales, Andrew; Hughes, Andrew O; Gall, Mark P

    2014-01-01

    Fine sediment continues to be a major diffuse pollution concern with its multiple effects on aquatic ecosystems. Mass concentrations (and loads) of fine sediment are usually measured and modelled, apparently with the assumption that environmental effects of sediment are predictable from mass concentrations. However, some severe impacts of fine sediment may not correlate well with mass concentration, notably those related to light attenuation by suspended particles. Light attenuation per unit mass concentration of suspended particulate matter in waters varies widely with particle size, shape and composition. Data for suspended sediment concentration, turbidity and visual clarity (which is inversely proportional to light beam attenuation) from 77 diverse New Zealand rivers provide valuable insights into the mutual relationships of these quantities. Our analysis of these relationships, both across multiple rivers and within individual rivers, supports the proposition that light attenuation by fine sediment is a more generally meaningful basis for environmental management than sediment mass. Furthermore, optical measurements are considerably more practical, being much cheaper (by about four-fold) to measure than mass concentrations, and amenable to continuous measurement. Mass concentration can be estimated with sufficient precision for many purposes from optical surrogates locally calibrated for particular rivers.

  4. Peritoneal fluid causing inferior attenuation on SPECT thallium-201 myocardial imaging in women

    SciTech Connect

    Rab, S.T.; Alazraki, N.P.; Guertler-Krawczynska, E.

    1988-11-01

    On SPECT thallium images, myocardial left ventricular (LV) anterior wall attenuation due to breast tissue is common in women. In contrast, in men, inferior wall counts are normally decreased compared to anterior counts. The purpose of this report is to describe cases of inferior wall attenuation of counts in women caused by peritoneal fluid, not myocardial disease. Twelve consecutive SPECT thallium myocardial studies performed in women on peritoneal dialysis, being evaluated for kidney transplant, were included in this study. For all studies, 3.5 mCi 201Tl were injected intravenously. Thirty-two images were acquired over 180 degrees (45 degrees RAO progressing to 45 degrees LPO) at 40 sec per stop. SPECT images were reviewed in short axis, horizontal long and vertical long axes. Data were also displayed in bullseye format with quantitative comparison to gender-matched normal files. Ten of 12 female patients studied had inferior wall defects on images, confirmed by bullseye display. All patients had approximately 2 liters of peritoneal fluid. Review of planar rotational views showed diaphragm elevation and fluid margin attenuations affecting left ventricular inferior wall. Thus, peritoneal fluid is a cause of inferior attenuation on 201Tl cardiac imaging.

  5. Attenuation of near-IR light through dentin at wavelengths from 1300-1650-nm

    NASA Astrophysics Data System (ADS)

    Chan, Andrew C.; Darling, Cynthia L.; Chan, Kenneth H.; Fried, Daniel

    2014-02-01

    Light scattering in dental enamel decreases markedly from the UV to the near-IR and recent studies employing near-IR transillumination and reflectance imaging including optical coherence tomography indicate that this wavelength region is ideally suited for imaging dental caries due to the high transparency of enamel. The opacity of dentin is an important factor in optimizing the contrast of demineralization in reflectance measurements. It also influences the contrast of occlusal lesions in transillumination. Light scattering in dentin is an order of magnitude larger than in enamel, it is highly anisotropic and has a different spectral light scattering dependence than enamel. The objective of this study was to measure the optical attenuation of near-IR light through dentin at near-IR wavelengths from 1300-1650-nm. In this study the collimated transmission of near-IR light through polished thin sections of dentin of 0.05 to 0.6 mm thickness was measured. Beer-Lambert plots show that the attenuation coefficients range in magnitude from 20 to 40 cm-1. Attenuation increased significantly with increasing wavelength and the increases were not entirely consistent with increased water absorption.

  6. Dependence of light attenuation and backscattering on collagen concentration and chondrocyte density in agarose scaffolds.

    PubMed

    Puhakka, P H; Ylärinne, J H; Lammi, M J; Saarakkala, S; Tiitu, V; Kröger, H; Virén, T; Jurvelin, J S; Töyräs, J

    2014-11-07

    Optical coherence tomography (OCT) has been applied for high resolution imaging of articular cartilage. However, the contribution of individual structural elements of cartilage on OCT signal has not been thoroughly studied. We hypothesize that both collagen and chondrocytes, essential structural components of cartilage, act as important light scatterers and that variation in their concentrations can be detected by OCT through changes in backscattering and attenuation. To evaluate this hypothesis, we established a controlled model system using agarose scaffolds embedded with variable collagen concentrations and chondrocyte densities. Using OCT, we measured the backscattering coefficient (µb) and total attenuation coefficient (µt) in these scaffolds. Along our hypothesis, light backscattering and attenuation in agarose were dependent on collagen concentration and chondrocyte density. Significant correlations were found between µt and chondrocyte density (ρ = 0.853, p < 0.001) and between µt and collagen concentration (ρ = 0.694, p < 0.001). µb correlated significantly with chondrocyte density (ρ = 0.504, p < 0.001) but not with collagen concentration (ρ = 0.103, p = 0.422) of the scaffold. Thus, quantitation of light backscattering and, especially, attenuation could be valuable when evaluating the integrity of soft tissues, such as articular cartilage with OCT.

  7. The Physics of the Gas Attenuator for the Linac Coherent Light Source (LCLS)

    SciTech Connect

    Ryutov, D.D.; Bionta, R.M.; Hau-Riege, S.P.; Kishiyama, K.I.; McMahon, D.; Roeben, M.D.; Shen, S.; Stefan, P.M.; /SLAC

    2011-02-07

    A systematic assessment of a variety of physics issues affecting the performance of the LCLS X-ray beam attenuator is presented. Detailed analysis of the gas flow in the gas attenuator and in the apertures is performed. A lot of attention is directed towards the gas ionization and heating by intense X-ray pulses. The role of these phenomena in possible deviations of the attenuation coefficient from its 'dialed in' value is evaluated and found small in most cases. Other sources of systematic and statistical errors are also discussed. The regimes where the errors may reach a few percent correspond to the lower X-ray energies (less than 2 keV) and highest beam intensities. Other effects discussed include chemical interaction of the gas with apertures, shock formation in the transonic flow in the apertures of the attenuator, generation of electromagnetic wakes in the gas, and head-to-tail variation of the attenuation caused by the ionization of gas or solid. Possible experimental tests of the consistency of the physics assumptions used in the concept of the gas attenuator are discussed. Interaction of X-rays with the solid attenuator (that will be used at higher X-ray energies, from 2.5 to 8 keV) is considered and thermo-mechanical effects caused by the beam heating are evaluated. Wave-front distortions induced by non-uniform heating of both the solid and the gas are found to be small. An overall conclusion drawn from the analysis presented is that the attenuator will be a reliable and highly versatile device, provided that some caution is exercised in its use for highest beam intensities at lowest X-ray energies.

  8. Light attenuation in rat skin following low level laser therapy on burn healing process

    NASA Astrophysics Data System (ADS)

    Teixeira Silva, Daniela Fátima; Simões Ribeiro, Martha

    2010-04-01

    Low-level laser therapy (LLLT) is commonly used to accelerate wound healing. Besides, the technique of imaging the light distribution inside biological tissues permits us to understand several effects about light-tissue interaction. The purpose of this study was to determine the relative attenuation coefficient of the light intensity in healthy and burned skin rats during cutaneous repair following LLLT or not. Two burns about 6mm in diameter were cryogenerated using liquid N2 on the back of 15 rats. Lesion L was irradiated by a He-Ne laser (λ= 632.8nm) and fluence 1.0J/cm2; Lesion C was control and received sham irradiation. A healthy skin area (H) was also analyzed. The lesions were irradiated at days 3, 7, 10 and 14 post-burning. The animals were euthanized at days 3, 10 and 31 and skin samples were carefully removed and placed between two microscope slides, spaced by z= 1mm. A laser beam irradiated the sandwiched tissue from epidermis to dermis. A CCD camera was placed orthogonal to the beam path and it photographed the distribution of the scattered light. The light decay occurred according to the Beer's Law. Significance was accepted at p <0.01 by using t-Student test. Our results show that the light decay along any direction was close to an exponential. Burned skin samples presented decay significantly faster than healthy skin samples. Besides, attenuation coefficient changed during burning healing comparing treated and control lesions. These findings suggest that the relative attenuation coefficient is a suitable parameter to optimize LLLT during wound healing.

  9. Attenuation of 1310- and 1550-nm laser light through sound dental enamel

    NASA Astrophysics Data System (ADS)

    Jones, Robert S.; Fried, Daniel

    2002-06-01

    Inexpensive laser diodes and fiber-optic technology have revived optical transillumination as a promising diagnostic method for the early detection of dental caries. The principal factor limiting transillumination through dental hard tissue is light scattering in the normal enamel and dentin. Previous studies have shown that the scattering coefficient decreases with increasing wavelength. Therefore, the near-IR region is likely to be well suited for fiber optic transillumination. The objective of this study was to measure the optical attenuation of near-IR light through dental enamel at 1310-nm and 1550-nm. These laser wavelengths are readily available due to their suitability for application to fiber optic communication. In this study the collimated transmission of laser light through polished thin sections of dental enamel for various thickness from 0.1 to 2.5 mm was measured in cuvettes of index matching fluid with n= 1.63. Beer-Lambert plots show that the attenuation coefficients are 3.1+/- 0.17cm-1 and 3.8+/- 0.17cm-1 for 1310-nm and 1550-nm, respectively. This study indicates that near-IR laser wavelengths are well-suited for the transillumination of dental enamel for caries detection since the attenuation through normal tissue is an order of magnitude less than in the visible.

  10. Attenuated orexinergic signaling underlies depression-like responses induced by daytime light deficiency

    PubMed Central

    Deats, Sean P.; Adidharma, Widya; Lonstein, Joseph S.; Yan, Lily

    2014-01-01

    Light has profound effects on mood, as exemplified by seasonal affective disorder (SAD) and the beneficial effects of bright light therapy. However, the underlying neural pathways through which light regulates mood are not well understood. Our previous work has developed the diurnal grass rat, Arvicanthis niloticus, as an animal model of SAD (Leach et al., 2013a, Leach et al., 2013b). By utilizing a 12:12hr Dim Light:Dark (DLD) paradigm that simulates the lower light intensity of winter, we showed that the animals housed in DLD exhibited increased depression-like behaviors in the forced swim test (FST) and sweet solution preference (SSP) compared to animals housed in bright light during the day (BLD). The objective of the present study was to test the hypothesis that light affects mood by acting on the brain orexinergic system in the diurnal grass rat model of SAD. First, orexinA immunoreactivity (OXA-ir) was examined in DLD and BLD grass rats. The results revealed a reduction in the number of OXA-ir neurons in the hypothalamus and attenuated OXA-ir fiber density in the dorsal raphe nucleus of animals in the DLD compared to those in the BLD group. Then, the animals in BLD were treated systemically with SB-334867, a selective orexin 1 receptor (OX1R) antagonist, which led to a depressive phenotype characterized by increased immobility in the FST and a decrease in SSP compared to vehicle-treated controls. The results suggest that attenuated orexinergic signaling is associated with increased depression-like behaviors in grass rats, and support the hypothesis that the orexinergic system mediates the effects of light on mood. PMID:24813431

  11. Attenuated orexinergic signaling underlies depression-like responses induced by daytime light deficiency.

    PubMed

    Deats, S P; Adidharma, W; Lonstein, J S; Yan, L

    2014-07-11

    Light has profound effects on mood, as exemplified by seasonal affective disorder (SAD) and the beneficial effects of bright light therapy. However, the underlying neural pathways through which light regulates mood are not well understood. Our previous work has developed the diurnal grass rat, Arvicanthis niloticus, as an animal model of SAD (Leach et al., 2013a,b). By utilizing a 12:12-h dim light:dark (DLD) paradigm that simulates the lower light intensity of winter, we showed that the animals housed in DLD exhibited increased depression-like behaviors in the forced swim test (FST) and sweet solution preference (SSP) compared to animals housed in bright light during the day (BLD). The objective of the present study was to test the hypothesis that light affects mood by acting on the brain orexinergic system in the diurnal grass rat model of SAD. First, orexin A immunoreactivity (OXA-ir) was examined in DLD and BLD grass rats. Results revealed a reduction in the number of OXA-ir neurons in the hypothalamus and attenuated OXA-ir fiber density in the dorsal raphe nucleus of animals in the DLD compared to those in the BLD group. Then, the animals in BLD were treated systemically with SB-334867, a selective orexin 1 receptor (OX1R) antagonist, which led to a depressive phenotype characterized by increased immobility in the FST and a decrease in SSP compared to vehicle-treated controls. Results suggest that attenuated orexinergic signaling is associated with increased depression-like behaviors in grass rats, and support the hypothesis that the orexinergic system mediates the effects of light on mood.

  12. Attenuated familial adenomatous polyposis with desmoids caused by an APC mutation

    PubMed Central

    Ikenoue, Tsuneo; Yamaguchi, Kiyoshi; Komura, Mitsuhiro; Imoto, Seiya; Yamaguchi, Rui; Shimizu, Eigo; Kasuya, Shinichi; Shibuya, Tetsuo; Hatakeyama, Seira; Miyano, Satoru; Furukawa, Yoichi

    2015-01-01

    We present here a case of attenuated familial adenomatous polyposis (AFAP) with a family history of desmoids and thyroid tumors. This patient had no colonic polyps but did have multiple desmoids. Genetic analysis identified a 4-bp deletion in codon 2644 (c.7932_7935delTTAT: p.Tyr2645LysfsX14) of the adenomatous polyposis coli (APC) gene. In cases with limited numbers of colonic polyps and desmoids, AFAP may be caused by a mutation in the 3′ region of APC. PMID:27081525

  13. Xanthomonas campestris attenuates virulence by sensing light through a bacteriophytochrome photoreceptor.

    PubMed

    Bonomi, Hernán R; Toum, Laila; Sycz, Gabriela; Sieira, Rodrigo; Toscani, Andrés M; Gudesblat, Gustavo E; Leskow, Federico C; Goldbaum, Fernando A; Vojnov, Adrián A; Malamud, Florencia

    2016-11-01

    Phytochromes constitute a major photoreceptor family found in plants, algae, fungi, and prokaryotes, including pathogens. Here, we report that Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot disease which affects cruciferous crops worldwide, codes for a functional bacteriophytochrome (XccBphP). XccBphP possesses an N-terminal PAS2-GAF-PHY photosensory domain triad and a C-terminal PAS9 domain as its output module. Our results show that illumination of Xcc, prior to plant infection, attenuates its virulence in an XccBphP-dependent manner. Moreover, in response to light, XccBphP downregulates xanthan exopolysaccharide production and biofilm formation, two known Xcc virulence factors. Furthermore, the XccbphP null mutant shows enhanced virulence, similar to that of dark-adapted Xcc cultures. Stomatal aperture regulation and callose deposition, both well-established plant defense mechanisms against bacterial pathogens, are overridden by the XccbphP strain. Additionally, an RNA-Seq analysis reveals that far-red light or XccBphP overexpression produces genomewide transcriptional changes, including the inhibition of several Xcc virulence systems. Our findings indicate that Xcc senses light through XccBphP, eliciting bacterial virulence attenuation via downregulation of bacterial virulence factors. The capacity of XccBphP to respond to light both in vitro and in vivo was abolished by a mutation on the conserved Cys13 residue. These results provide evidence for a novel bacteriophytochrome function affecting an infectious process.

  14. Chronic altitude plus carbon monoxide exposure causes left ventricular hypertrophy but an attenuation of coronary capillarity

    SciTech Connect

    McDonagh, P.F.; Reynolds, J.M.; McGrath, J.J.

    1986-03-05

    To determine the nature of the cardiomegaly and coronary capillarity changes that occur with chronic hypoxia plus carbon monoxide (CO) exposure, F-344 rats (64-69 days old) were exposed to simulated altitude (18,000 ft) and four doses of CO (0, 50, 100, and 500 ppm) for six weeks. Left (LVT) and right (RVT) ventricular thickness and total coronary capillary density (LV Caps) were measured from sections of KCl-arrested hearts. Heart weight: Body weight ratios (HW:BW) were also calculated. Thus, altitude alone caused RV hypertrophy and an increase in LV Caps. Altitude plus CO attenuated the capillarity increase and caused further thickening of the LV but not the RV, suggesting concentric LV hypertrophy due to CO.

  15. Light attenuation in a semitransparent foam sheet—Thickness measurement for industrial use

    NASA Astrophysics Data System (ADS)

    Ueda, Masahiro; Mizuno, Sanae; Matsumura, Akio; Tohjyo, Fumio

    An optical method for measuring the thickness of heterogeneous materials has been studied. The method is based on the light attenuation theory. A complete system has been constructed in order to demonstrate the applicability of the present method for industrial use. The experimental set-up consists of semiconductor lasers, focusing lenses, photo-diodes serving as a power meter and a personal computer with an A/D converter for data acquisition. Averaging of numerous measurements is required in the present method because the heterogeneous cell structure of the foam material yields large fluctuations in transmitted light levels. The fluctuations can be reduced to below 1% of the transmitted light power by 80 times averaging. The error of the measurement is considered to be a few tens of micrometers in thickness. The present system is capable of sampling data at a rate of 400 Hz and has been successfully applied to a manufacturing process.

  16. Epidermal coumaroyl anthocyanins protect sweet basil against excess light stress: multiple consequences of light attenuation.

    PubMed

    Tattini, Massimiliano; Landi, Marco; Brunetti, Cecilia; Giordano, Cristiana; Remorini, Damiano; Gould, Kevin S; Guidi, Lucia

    2014-11-01

    The putative photoprotective role of foliar anthocyanins continues to attract heated debate. Strikingly different experimental set-ups coupled with a poor knowledge of anthocyanin identity have likely contributed to such disparate opinions. Here, the photosynthetic responses to 30 or 100% solar irradiance were compared in two cultivars of basil, the green-leafed Tigullio (TG) and the purple-leafed Red Rubin (RR). Coumaroyl anthocyanins in RR leaf epidermis significantly mitigated the effects of high light stress. In full sunlight, RR leaves displayed several shade-plant traits; they transferred less energy than did TG to photosystem II (PSII), and non-photochemical quenching was lower. The higher xanthophyll cycle activity in TG was insufficient to prevent inactivation of PSII in full sunlight. However, TG was the more efficient in the shade; RR was far less able to accommodate a large change in irradiance. Investment of carbon to phenylpropanoid biosynthesis was more in RR than in TG in the shade, and was either greatly enhanced in TG or varied little in RR because of high sunlight. The metabolic cost of photoprotection was lower whereas light-induced increase in biomass production was higher in RR than in TG, thus making purple basil the more light tolerant. Purple basil appears indeed to display the conservative resource-use strategy usually observed in highly stress tolerant species. We conclude that the presence of epidermal coumaroyl anthocyanins confers protective benefits under high light, but it is associated with a reduced plasticity to accommodate changing light fluxes as compared with green leaves.

  17. Prior methamphetamine self-administration attenuates the dopaminergic deficits caused by a subsequent methamphetamine exposure.

    PubMed

    McFadden, Lisa M; Vieira-Brock, Paula L; Hanson, Glen R; Fleckenstein, Annette E

    2015-06-01

    Others and we have reported that prior methamphetamine (METH) exposure attenuates the persistent striatal dopaminergic deficits caused by a subsequent high-dose "binge" METH exposure. The current study investigated intermediate neurochemical changes that may contribute to, or serve to predict, this resistance. Rats self-administered METH or saline for 7 d. On the following day (specifically, 16 h after the conclusion of the final METH self-administration session), rats received a binge exposure of METH or saline (so as to assess the impact of prior METH self-administration), or were sacrificed without a subsequent METH exposure (i.e., to assess the status of the rats at what would have been the initiation of the binge METH treatment). Results revealed that METH self-administration per se decreased striatal dopamine (DA) transporter (DAT) function and DA content, as assessed 16 h after the last self-administration session. Exposure to a binge METH treatment beginning at this 16-h time point decreased DAT function and DA content as assessed 1 h after the binge METH exposure: this effect on DA content (but not DAT function) was attenuated if rats previously self-administered METH. In contrast, 24 h after the binge METH treatment prior METH self-administration: 1) attenuated deficits in DA content, DAT function and vesicular monoamine transporter-2 function; and 2) prevented increases in glial fibrillary acidic protein and DAT complex immunoreactivity. These data suggest that changes 24 h, but not 1 h, after binge METH exposure are predictive of tolerance against the persistence of neurotoxic changes following binge METH exposures.

  18. [Light chain deposition disease as a cause of renal failure].

    PubMed

    Wohl, P; Chadimová, M; Englis, M; Táborský, P; Rossmann, P; Matl, I

    1998-11-30

    The objective of the paper is to draw attention to a rare cause of rapidly progressing renal failure which developed in the course of four months as a result of light chain deposition disease. The authors submit two case-histories of the disease assessed by renal biopsy after previous clinical and laboratory suspicion of monoclonal gammapathy. In one patient in the sternal punctate plasmacytoma was diagnosed and in the second case it was not possible to detect any type of monoclonal gammapathy or another possible cause of disease. Renal failure was in both cases irreversible and both patients were enlisted in regular haemodialyzation treatment.

  19. Paradoxical Sleep Deprivation Causes Cardiac Dysfunction and the Impairment Is Attenuated by Resistance Training

    PubMed Central

    Giampá, Sara Quaglia de Campos; Mônico-Neto, Marcos; de Mello, Marco Tulio; Souza, Helton de Sá; Tufik, Sergio; Lee, Kil Sun; Koike, Marcia Kiyomi; dos Santos, Alexandra Alberta; Antonio, Ednei Luiz; Serra, Andrey Jorge; Tucci, Paulo José Ferreira

    2016-01-01

    Background Paradoxical sleep deprivation activates the sympathetic nervous system and the hypothalamus-pituitary-adrenal axis, subsequently interfering with the cardiovascular system. The beneficial effects of resistance training are related to hemodynamic, metabolic and hormonal homeostasis. We hypothesized that resistance training can prevent the cardiac remodeling and dysfunction caused by paradoxical sleep deprivation. Methods Male Wistar rats were distributed into four groups: control (C), resistance training (RT), paradoxical sleep deprivation for 96 hours (PSD96) and both resistance training and sleep deprivation (RT/PSD96). Doppler echocardiograms, hemodynamics measurements, cardiac histomorphometry, hormonal profile and molecular analysis were evaluated. Results Compared to the C group, PSD96 group had a higher left ventricular systolic pressure, heart rate and left atrium index. In contrast, the left ventricle systolic area and the left ventricle cavity diameter were reduced in the PSD96 group. Hypertrophy and fibrosis were also observed. Along with these alterations, reduced levels of serum testosterone and insulin-like growth factor-1 (IGF-1), as well as increased corticosterone and angiotensin II, were observed in the PSD96 group. Prophylactic resistance training attenuated most of these changes, except angiotensin II, fibrosis, heart rate and concentric remodeling of left ventricle, confirmed by the increased of NFATc3 and GATA-4, proteins involved in the pathologic cardiac hypertrophy pathway. Conclusions Resistance training effectively attenuates cardiac dysfunction and hormonal imbalance induced by paradoxical sleep deprivation. PMID:27880816

  20. Methamphetamine treatment during development attenuates the dopaminergic deficits caused by subsequent high-dose methamphetamine administration.

    PubMed

    McFadden, Lisa M; Hoonakker, Amanda J; Vieira-Brock, Paula L; Stout, Kristen A; Sawada, Nicole M; Ellis, Jonathan D; Allen, Scott C; Walters, Elliot T; Nielsen, Shannon M; Gibb, James W; Alburges, Mario E; Wilkins, Diana G; Hanson, Glen R; Fleckenstein, Annette E

    2011-08-01

    Administration of high doses of methamphetamine (METH) causes persistent dopaminergic deficits in both nonhuman preclinical models and METH-dependent persons. Noteworthy, adolescent [i.e., postnatal day (PND) 40] rats are less susceptible to this damage than young adult (PND90) rats. In addition, biweekly treatment with METH, beginning at PND40 and continuing throughout development, prevents the persistent dopaminergic deficits caused by a "challenge" high-dose METH regimen when administered at PND90. Mechanisms underlying this "resistance" were thus investigated. Results revealed that biweekly METH treatment throughout development attenuated both the acute and persistent deficits in VMAT2 function, as well as the acute hyperthermia, caused by a challenge METH treatment. Pharmacokinetic alterations did not appear to contribute to the protection afforded by the biweekly treatment. Maintenance of METH-induced hyperthermia abolished the protection against both the acute and persistent VMAT2-associated deficits suggesting that alterations in thermoregulation were caused by exposure of rats to METH during development. These findings suggest METH during development prevents METH-induced hyperthermia and the consequent METH-related neurotoxicity.

  1. Methamphetamine treatment during development attenuates the dopaminergic deficits caused by subsequent high-dose methamphetamine administration

    PubMed Central

    McFadden, Lisa M; Hoonakker, Amanda J; Vieira-Brock, Paula L; Stout, Kristen A; Sawada, Nicole M; Ellis, Jonathan D; Allen, Scott C; Walters, Elliot T; Nielsen, Shannon M; Gibb, James W; Alburges, Mario E; Wilkins, Diana G; Hanson, Glen R; Fleckenstein, Annette E

    2013-01-01

    Administration of high doses of methamphetamine (METH) causes persistent dopaminergic deficits in both nonhuman preclinical models and METH-dependent persons. Noteworthy, adolescent (i.e., postnatal day (PND) 40) rats are less susceptible to this damage than young adult (PND90) rats. In addition, biweekly treatment with METH, beginning at PND40 and continuing throughout development, prevents the persistent dopaminergic deficits caused by a “challenge” high-dose METH regimen when administered at PND90. Mechanisms underlying this “resistance” were thus investigated. Results revealed that biweekly METH treatment throughout development attenuated both the acute and persistent deficits in VMAT2 function, as well as the acute hyperthermia, caused by a challenge METH treatment. Pharmacokinetic alterations did not appear to contribute to the protection afforded by the biweekly treatment. Maintenance of METH-induced hyperthermia abolished the protection against both the acute and persistent VMAT2-associated deficits suggesting that alterations in thermoregulation were caused by exposure of rats to METH during development. These findings suggest METH during development prevents METH-induced hyperthermia and the consequent METH-related neurotoxicity. PMID:21190217

  2. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

    NASA Astrophysics Data System (ADS)

    Oestreich, W. K.; Ganju, N. K.; Pohlman, J. W.; Suttles, S. E.

    2016-02-01

    Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM-fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m-1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from -19.7 to -26.1 ‰ and -20.8 to -26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of DOC source to CDOM : f

  3. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

    USGS Publications Warehouse

    Oestreich, W.K.; Ganju, Neil Kamal; Pohlman, John; Suttles, Steven

    2016-01-01

    Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM–fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m−1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from −19.7 to −26.1 ‰ and −20.8 to −26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of

  4. Long-Term Changes in Light Scattering in Chesapeake Bay Inferred from Secchi Depth, Light Attenuation, and Remote Sensing Measurements

    NASA Technical Reports Server (NTRS)

    Gallegos, Charles L.; Werdell, P. Jeremy; McClain, Charles R.

    2011-01-01

    The relationship between the Secchi depth (Z(sub SD)) and the diffuse attenuation coefficient for photosynthetically active radiation (K(sub d)(PAR)), and in particular the product of the two, Z(sub SD) X K(sub d)(PAR), is governed primarily by the ratio of light scattering to absorption. We analyzed measurements of Z(sub SD) and K(sub d)(PAR) at main stem stations in Chesapeake Bay and found that the Z(sub SD) X K(sub d)(PAR) product has declined at rates varying from 0.020 to 0.033 /yr over the 17 to 25 years of measurement, implying that there has been a long -term increase in the scattering-to-absorption ratio. Remote sensing reflectance at the green wavelength most relevant to Z(sub SD) and K(sub d)(PAR) in these waters, R(sub rs)(555), did not exhibit an increasing trend over the 10 years of available measurements. To reconcile the observations we constructed a bio-optical model to calculate Z(sub SD), K(sub d)(PAR), Z(sub SD) X K(sub d)(PAR), and R(sub rs)(555) as a function of light attenuating substances and their mass-specific absorption and scattering coefficients. When simulations were based exclusively on changes in concentrations of light attenuating substances, a declining trend in Z(sub SD) E K(sub d) entailed an increasing trend in R(sub rs)(555), contrary to observations. To simulate both decreasing Z(sub SD) X K(sub d)(PAR) and stationary R(sub rs)(555), it was necessary to allow for a declining trend in the ratio of backscattering to total scattering. Within our simulations, this was accomplished by increasing the relative proportion of organic detritus with high mass-specific scattering and low backscattering ratio. An alternative explanation not explicitly modeled is an increasing tendency for the particulate matter to occur in large aggregates. Data to discriminate between these alternatives are not available.

  5. Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes

    PubMed Central

    McWilliams-Koeppen, Helen P.; Foster, James S.; Hackenbrack, Nicole; Ramirez-Alvarado, Marina; Donohoe, Dallas; Williams, Angela; Macy, Sallie; Wooliver, Craig; Wortham, Dale; Morrell-Falvey, Jennifer; Foster, Carmen M.; Kennel, Stephen J.; Wall, Jonathan S.

    2015-01-01

    Light chain (AL) amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(P)H-dependent oxidoreductase, without causing significant cell death. The presence of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. These data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils. PMID:26393799

  6. Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes

    SciTech Connect

    McWilliams-Koeppen, Helen P.; Foster, James S.; Hackenbrack, Nicole; Ramirez-Alvarado, Marina; Donohoe, Dallas; Williams, Angela; Macy, Sallie; Wooliver, Craig; Wortham, Dale; Morrell-Falvey, Jennifer; Foster, Carmen M.; Kennel, Stephen J.; Wall, Jonathan S.

    2015-09-22

    Light chain (AL) amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(P)H-dependent oxidoreductase, without causing significant cell death. The presence of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. Ultimately, these data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.

  7. Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes

    DOE PAGES

    McWilliams-Koeppen, Helen P.; Foster, James S.; Hackenbrack, Nicole; ...

    2015-09-22

    Light chain (AL) amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(P)H-dependent oxidoreductase, without causing significant cell death. The presencemore » of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. Ultimately, these data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.« less

  8. Prolonged daily light exposure increases body fat mass through attenuation of brown adipose tissue activity.

    PubMed

    Kooijman, Sander; van den Berg, Rosa; Ramkisoensing, Ashna; Boon, Mariëtte R; Kuipers, Eline N; Loef, Marieke; Zonneveld, Tom C M; Lucassen, Eliane A; Sips, Hetty C M; Chatzispyrou, Iliana A; Houtkooper, Riekelt H; Meijer, Johanna H; Coomans, Claudia P; Biermasz, Nienke R; Rensen, Patrick C N

    2015-05-26

    Disruption of circadian rhythmicity is associated with obesity and related disorders, including type 2 diabetes and cardiovascular disease. Specifically, prolonged artificial light exposure associates with obesity in humans, although the underlying mechanism is unclear. Here, we report that increasing the daily hours of light exposure increases body adiposity through attenuation of brown adipose tissue (BAT) activity, a major contributor of energy expenditure. Mice exposed to a prolonged day length of 16- and 24-h light, compared with regular 12-h light, showed increased adiposity without affecting food intake or locomotor activity. Mechanistically, we demonstrated that prolonged day length decreases sympathetic input into BAT and reduces β3-adrenergic intracellular signaling. Concomitantly, prolonging day length decreased the uptake of fatty acids from triglyceride-rich lipoproteins, as well as of glucose from plasma selectively by BAT. We conclude that impaired BAT activity is an important mediator in the association between disturbed circadian rhythm and adiposity, and anticipate that activation of BAT may overcome the adverse metabolic consequences of disturbed circadian rhythmicity.

  9. Prolonged daily light exposure increases body fat mass through attenuation of brown adipose tissue activity

    PubMed Central

    Kooijman, Sander; van den Berg, Rosa; Ramkisoensing, Ashna; Boon, Mariëtte R.; Kuipers, Eline N.; Loef, Marieke; Zonneveld, Tom C. M.; Lucassen, Eliane A.; Sips, Hetty C. M.; Chatzispyrou, Iliana A.; Houtkooper, Riekelt H.; Meijer, Johanna H.; Coomans, Claudia P.; Biermasz, Nienke R.; Rensen, Patrick C. N.

    2015-01-01

    Disruption of circadian rhythmicity is associated with obesity and related disorders, including type 2 diabetes and cardiovascular disease. Specifically, prolonged artificial light exposure associates with obesity in humans, although the underlying mechanism is unclear. Here, we report that increasing the daily hours of light exposure increases body adiposity through attenuation of brown adipose tissue (BAT) activity, a major contributor of energy expenditure. Mice exposed to a prolonged day length of 16- and 24-h light, compared with regular 12-h light, showed increased adiposity without affecting food intake or locomotor activity. Mechanistically, we demonstrated that prolonged day length decreases sympathetic input into BAT and reduces β3-adrenergic intracellular signaling. Concomitantly, prolonging day length decreased the uptake of fatty acids from triglyceride-rich lipoproteins, as well as of glucose from plasma selectively by BAT. We conclude that impaired BAT activity is an important mediator in the association between disturbed circadian rhythm and adiposity, and anticipate that activation of BAT may overcome the adverse metabolic consequences of disturbed circadian rhythmicity. PMID:25964318

  10. Near-Infrared Light Therapy to Attenuate Strength Loss After Strenuous Resistance Exercise

    PubMed Central

    Larkin-Kaiser, Kelly A.; Christou, Evangelos; Tillman, Mark; George, Steven; Borsa, Paul A.

    2015-01-01

    Context: Near-infrared (NIR) light therapy is purported to act as an ergogenic aid by enhancing the contractile function of skeletal muscle. Improving muscle function is a new avenue for research in the area of laser therapy; however, very few researchers have examined the ergogenic effects of NIR light therapy and the influence it may have on the recovery process during rehabilitation. Objective: To evaluate the ergogenic effect of NIR light therapy on skeletal muscle function. Design: Crossover study. Setting: Controlled laboratory. Patients or Other Participants: Thirty-nine healthy men (n = 21) and women (n = 18; age = 20.0 ± 0.2 years, height = 169 ± 2 cm, mass = 68.4 ± 1.8 kg, body mass index = 23.8 ± 0.4 kg/m2). Intervention(s): Each participant received active and sham treatments on the biceps brachii muscle on 2 separate days. The order of treatment was randomized. A class 4 laser with a cumulative dose of 360 J was used for the active treatment. After receiving the treatment on each day, participants completed an elbow-flexion resistance-exercise protocol. Main Outcome Measure(s): The dependent variables were elbow range of motion, muscle point tenderness, and strength (peak torque). Analysis of variance with repeated measures was used to assess changes in these measures between treatments at baseline and at follow-up, 48 hours postexercise. Additionally, immediate strength loss postexercise was compared between treatments using a paired t test. Results: Preexercise to postexercise strength loss for the active laser treatment, although small, was less than with the sham treatment (P = .05). Conclusions: Applied to skeletal muscle before resistance exercise, NIR light therapy effectively attenuated strength loss. Therefore, NIR light therapy may be a beneficial, noninvasive modality for improving muscle function during rehabilitation after musculoskeletal injury. However, future studies using higher treatment doses are warranted. PMID:25397864

  11. Two light attenuation models for automatic diameter measurement of the blood vessels.

    PubMed

    Michoud, E; Carpentier, P; Franco, A; Intaglietta, M

    1993-04-01

    The Lambert-Beer's law of the absorption of the light by blood in a vessel is used to model the light attenuation by a blood vessel that is transilluminated. Two models are used for an automatic vessel diameter determination for intravital microscopy. Some requirements for the photometric system have to be met in order to reduce errors due to light scattering. In these conditions, a videodensitometric pattern of the cross-section of the vessel can be fitted by the different models in order to obtain the diameter of the vessel. The first model proposed uses a uniformly distributed red blood cell column. A non-linear estimation of the diameter is done with the Levenberg-Marquardt method in 2 sec, using a regular PC386 microcomputer. The second one takes in account the presence of a plasma layer and computes the diameter of the red blood cell column and the diameter of the vessel in one minute. These models can be used for pharmacological studies or for a better understanding of the formation of a transilluminated intravital image. They can also be used for angiographic images.

  12. UV Attenuation Near Coral Reefs in the Florida Keys: Light Absorption by CDOM and Particles

    NASA Astrophysics Data System (ADS)

    Shank, G. C.; Zepp, R. G.; Bartels, E.

    2005-12-01

    We have investigated the roles of chromophoric dissolved organic matter (CDOM) and suspended particles in the attenuation of UV radiation in the middle and lower regions of the Florida Keys. Extended exposure to UV radiation, along with elevated sea surface temperatures, impairs physiological processes in corals and contributes to bleaching episodes. Corals in the Florida Keys experience large variations in UV exposure due to several factors including tidal exchange and fluctuating meteorological conditions. CDOM derived from mangroves and seagrass beds is the primary attenuator of UV radiation near coral reefs in our study area. CDOM accounts for more than 90 percent of the absorption of UVB irradiance (305 nm) throughout the region. However, we have determined using the quantitative filter technique that up to 25 percent of the downwelling UVA irradiance at 380 nm may be directly absorbed by suspended particles. Resuspension from within or near the reef structure appears to be the primary particle source as phytoplankton pigments typically comprise less than 20 percent of the particle UV absorption capacity near reef sampling sites. Our research also has implications for remote sensing applications as light absorbed by particles must be considered when modeling optical data from satellites. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

  13. Evidence of light depolarization in grazing incidence germanium attenuated total reflection prisms.

    PubMed

    Rochat, Névine; Klymko, Nancy; Licitra, Christophe; Gambacorti, Narciso

    2011-09-01

    Attenuated total reflection (ATR) infrared absorption spectroscopy is a well-known vibrational spectroscopy technique for many different applications. In recent years this technique has been used to detect thin layer(s) lying on a solid substrate. Such a sample needs high pressure to ensure good optical contact between sample and prism and a p-polarization to enhance the signal to be detected. Such conditions have not been detailed in the literature regarding the effect of high pressure on the ATR measurement. This study shows the detrimental effect of high pressure on the ATR spectra. This effect is related to light depolarization induced by the germanium prism under high pressure. Moreover, the importance of polarizer position in the optical bench is highlighted. Indeed, due to the pressure-induced depolarization of the prism, the polarizer has to be placed before the prism to limit undesirable effects on the ATR spectrum baseline.

  14. Attenuation coefficient of the light in skin of BALB/c and C57BL/6 mice

    NASA Astrophysics Data System (ADS)

    Silva, C. R.; Camargo, C. F. M.; Aureliano, D. P.; De Pretto, L. R.; Freitas, A. Z.; Ribeiro, M. S.

    2015-06-01

    Optical properties of the biological tissue play an important role to a correct use of optical techniques for therapy and diagnosis. The mice skin presents morphological differences due to characteristics such as gender, body mass and age. Murine models are frequently used in pre-clinical trials in optical therapy and diagnosis. Therefore, the assessment of the skin tissue in animal models is needed for a proper understanding of how light interacts with skin. Noninvasive techniques such as optical coherence tomography (OCT) have been used to obtain optical information of the tissue, as the attenuation coefficient, with the advantage of obtaining sectional images in real time. In this study, eight female BALB/c albino mice (twenty-four weeks old) and eight male C57BL/6 black mice (eight weeks old) were used to measure the attenuation coefficient of the light in the skin, utilizing the OCT technique, aiming to check for influence of the aging process. Two moments were assessed twenty-two weeks apart from each other. Our data show that the aging process significantly affects the light attenuation coefficient in mice skin. Twenty-two weeks after, statistical significant differences were observed between groups within a same strain. We conclude that light attenuation coefficient of mice skin may be influenced by factors such as disorganization of the dermis. Morphological aspects of skin should be taken into account in studies that involve optical strategies in murine models.

  15. Mutations in Myosin Light Chain Kinase Cause Familial Aortic Dissections

    PubMed Central

    Wang, Li; Guo, Dong-chuan; Cao, Jiumei; Gong, Limin; Kamm, Kristine E.; Regalado, Ellen; Li, Li; Shete, Sanjay; He, Wei-Qi; Zhu, Min-Sheng; Offermanns, Stephan; Gilchrist, Dawna; Elefteriades, John; Stull, James T.; Milewicz, Dianna M.

    2010-01-01

    Mutations in smooth muscle cell (SMC)-specific isoforms of α-actin and β-myosin heavy chain, two major components of the SMC contractile unit, cause familial thoracic aortic aneurysms leading to acute aortic dissections (FTAAD). To investigate whether mutations in the kinase that controls SMC contractile function (myosin light chain kinase [MYLK]) cause FTAAD, we sequenced MYLK by using DNA from 193 affected probands from unrelated FTAAD families. One nonsense and four missense variants were identified in MYLK and were not present in matched controls. Two variants, p.R1480X (c.4438C>T) and p.S1759P (c.5275T>C), segregated with aortic dissections in two families with a maximum LOD score of 2.1, providing evidence of linkage of these rare variants to the disease (p = 0.0009). Both families demonstrated a similar phenotype characterized by presentation with an acute aortic dissection with little to no enlargement of the aorta. The p.R1480X mutation leads to a truncated protein lacking the kinase and calmodulin binding domains, and p.S1759P alters amino acids in the α-helix of the calmodulin binding sequence, which disrupts kinase binding to calmodulin and reduces kinase activity in vitro. Furthermore, mice with SMC-specific knockdown of Mylk demonstrate altered gene expression and pathology consistent with medial degeneration of the aorta. Thus, genetic and functional studies support the conclusion that heterozygous loss-of-function mutations in MYLK are associated with aortic dissections. PMID:21055718

  16. Characterizing light attenuation within Northwest Florida Estuaries: Implications for RESTORE Act water quality monitoring.

    PubMed

    Conmy, Robyn N; Schaeffer, Blake A; Schubauer-Berigan, Joseph; Aukamp, Jessica; Duffy, Allyn; Lehrter, John C; Greene, Richard M

    2017-01-30

    Water Quality (WQ) condition is based on ecosystem stressor indicators (e.g. water clarity) which are biogeochemically important and critical when considering the Deepwater Horizon oil spill restoration efforts under the 2012 RESTORE Act. Nearly all of the proposed RESTORE projects list restoring WC as a goal, but 90% neglect water clarity. Here, dynamics of optical constituents impacting clarity are presented from a 2009-2011 study within Pensacola, Choctawhatchee, St. Andrew and St. Joseph estuaries (targeted RESTORE sites) in Northwest Florida. Phytoplankton were the smallest contribution to total absorption (at-wPAR) at 412nm (5-11%), whereas colored dissolved organic matter was the largest (61-79%). Estuarine at-wPAR was significantly related to light attenuation (KdPAR), where individual contributors to clarity and the influence of climatic events were discerned. Provided are conversion equations demonstrating interoperability of clarity indicators between traditional State-measured WQ measures (e.g. secchi disc), optical constituents, and even satellite remote sensing for obtaining baseline assessments.

  17. Robust incremental compensation of the light attenuation with depth in 3D fluorescence microscopy.

    PubMed

    Kervrann, C; Legland, D; Pardini, L

    2004-06-01

    Summary Fluorescent signal intensities from confocal laser scanning microscopes (CLSM) suffer from several distortions inherent to the method. Namely, layers which lie deeper within the specimen are relatively dark due to absorption and scattering of both excitation and fluorescent light, photobleaching and/or other factors. Because of these effects, a quantitative analysis of images is not always possible without correction. Under certain assumptions, the decay of intensities can be estimated and used for a partial depth intensity correction. In this paper we propose an original robust incremental method for compensating the attenuation of intensity signals. Most previous correction methods are more or less empirical and based on fitting a decreasing parametric function to the section mean intensity curve computed by summing all pixel values in each section. The fitted curve is then used for the calculation of correction factors for each section and a new compensated sections series is computed. However, these methods do not perfectly correct the images. Hence, the algorithm we propose for the automatic correction of intensities relies on robust estimation, which automatically ignores pixels where measurements deviate from the decay model. It is based on techniques adopted from the computer vision literature for image motion estimation. The resulting algorithm is used to correct volumes acquired in CLSM. An implementation of such a restoration filter is discussed and examples of successful restorations are given.

  18. Changes in Seismic Attenuation and Anisotropy Caused by the Local Stress Field of Ruapehu Volcano, New Zealand

    NASA Astrophysics Data System (ADS)

    Kuehler, T.; Savage, M.; Hurst, T.

    2006-12-01

    Temporal variations of seismic attenuation have been observed at different volcanoes around the world and seem to correlate with volcanic activity. Changes in seismic anisotropy orientation previously observed at Mt. Ruapehu Volcano in New Zealand suggest changes in stress after eruptions. The fast anisotropic orientation changed at least twice by up to 80° between 1994 and 2002. The stress field caused by repeated filling and depressurising of a magmatic dyke system presumably alters the alignment of cracks and hence anisotropy in the vicinity of the volcano. Such changes in crack alignment may also change attenuation. Seismic attenuation due to elastic and anelastic energy loss is the major process, apart from geometrical spreading, that decreases and modifies the amplitude of a propagating seismic wave. Attenuation around Mt. Ruapehu is measured between 1990 and 2005 using regional earthquakes originating from a nearby earthquake swarm recorded on 5 permanent seismometer stations. Cross-correlation of direct compressional (P) and shear (S) waves reveals a remarkable similarity of events from this ongoing seismic source. The attenuation (QC-1) of coda waves following the direct P and S waves is calculated using a single- scattering model. A best-fit equation of QC = Q0f^{α} with Q0=54(±7) and α=1.02(±0.06) shows an overall high frequency dependence of coda attenuation, which is characteristic for tectonically active regions. α increases at all stations in 1995 and decreases slowly in the years following volcanic eruptions in 1995/96. Relative change in integrated direct wave attenuation (δt*), is obtained using a spectral-ratio method in which spectra of individual 1-second P wave windows are compared to a reference spectrum. Results reveal a distinct change of δt* of about 0.13 s in a low- frequency band (1.5 - 6 Hz) at two stations in 1995/96. A simple model of fluid-filled cracks in a region about 5 km broad can explain both the anisotropy and

  19. Synonymous Deoptimization of Foot-and-Mouth Disease Virus Causes Attenuation In Vivo while Inducing a Strong Neutralizing Antibody Response

    PubMed Central

    Diaz-San Segundo, Fayna; Medina, Gisselle N.; Ramirez-Medina, Elizabeth; Velazquez-Salinas, Lauro; Koster, Marla; Grubman, Marvin J.

    2015-01-01

    ABSTRACT Codon bias deoptimization has been previously used to successfully attenuate human pathogens, including poliovirus, respiratory syncytial virus, and influenza virus. We have applied a similar technology to deoptimize the capsid-coding region (P1) of foot-and-mouth disease virus (FMDV). Despite the introduction of 489 nucleotide changes (19%), synonymous deoptimization of the P1 region rendered a viable FMDV progeny. The resulting strain was stable and reached cell culture titers similar to those obtained for wild-type (WT) virus, but at reduced specific infectivity. Studies in mice showed that 100% of animals inoculated with the FMDV A12 P1 deoptimized mutant (A12-P1 deopt) survived, even when the animals were infected at doses 100 times higher than the dose required to cause death by WT virus. All mice inoculated with the A12-P1 deopt mutant developed a strong antibody response and were protected against subsequent lethal challenge with WT virus at 21 days postinoculation. Remarkably, the vaccine safety margin was at least 1,000-fold higher for A12-P1 deopt than for WT virus. Similar patterns of attenuation were observed in swine, in which animals inoculated with A12-P1 deopt virus did not develop clinical disease until doses reached 1,000 to 10,000 times the dose required to cause severe disease in 2 days with WT A12. Consistently, high levels of antibody titers were induced, even at the lowest dose tested. These results highlight the potential use of synonymous codon pair deoptimization as a strategy to safely attenuate FMDV and further develop live attenuated vaccine candidates to control such a feared livestock disease. IMPORTANCE Foot-and-mouth disease (FMD) is one of the most feared viral diseases that can affect livestock. Although this disease appeared to be contained in developed nations by the end of the last century, recent outbreaks in Europe, Japan, Taiwan, South Korea, etc., have demonstrated that infection can spread rapidly, causing

  20. Design and expected performance of a fast neutron attenuation probe for light element density measurements

    DOE PAGES

    Sweany, M.; Marleau, P.

    2016-07-08

    In this paper, we present the design and expected performance of a proof-of-concept 32 channel material identification system. Our system is based on the energy-dependent attenuation of fast neutrons for four elements: hydrogen, carbon, nitrogen and oxygen. We describe a new approach to obtaining a broad range of neutron energies to probe a sample, as well as our technique for reconstructing the molar densities within a sample. The system's performance as a function of time-of-flight energy resolution is explored using a Geant4-based Monte Carlo. Our results indicate that, with the expected detector response of our system, we will be ablemore » to determine the molar density of all four elements to within a 20–30% accuracy in a two hour scan time. In many cases this error is systematically low, thus the ratio between elements is more accurate. This degree of accuracy is enough to distinguish, for example, a sample of water from a sample of pure hydrogen peroxide: the ratio of oxygen to hydrogen is reconstructed to within 8±0.5% of the true value. Lastly, with future algorithm development that accounts for backgrounds caused by scattering within the sample itself, the accuracy of molar densities, not ratios, may improve to the 5–10% level for a two hour scan time.« less

  1. Design and expected performance of a fast neutron attenuation probe for light element density measurements

    NASA Astrophysics Data System (ADS)

    Sweany, M.; Marleau, P.

    2016-10-01

    We present the design and expected performance of a proof-of-concept 32 channel material identification system. Our system is based on the energy-dependent attenuation of fast neutrons for four elements: hydrogen, carbon, nitrogen and oxygen. We describe a new approach to obtaining a broad range of neutron energies to probe a sample, as well as our technique for reconstructing the molar densities within a sample. The system's performance as a function of time-of-flight energy resolution is explored using a Geant4-based Monte Carlo. Our results indicate that, with the expected detector response of our system, we will be able to determine the molar density of all four elements to within a 20-30% accuracy in a two hour scan time. In many cases this error is systematically low, thus the ratio between elements is more accurate. This degree of accuracy is enough to distinguish, for example, a sample of water from a sample of pure hydrogen peroxide: the ratio of oxygen to hydrogen is reconstructed to within 8±0.5% of the true value. Finally, with future algorithm development that accounts for backgrounds caused by scattering within the sample itself, the accuracy of molar densities, not ratios, may improve to the 5-10% level for a two hour scan time.

  2. Design and expected performance of a fast neutron attenuation probe for light element density measurements

    SciTech Connect

    Sweany, M.; Marleau, P.

    2016-07-08

    In this paper, we present the design and expected performance of a proof-of-concept 32 channel material identification system. Our system is based on the energy-dependent attenuation of fast neutrons for four elements: hydrogen, carbon, nitrogen and oxygen. We describe a new approach to obtaining a broad range of neutron energies to probe a sample, as well as our technique for reconstructing the molar densities within a sample. The system's performance as a function of time-of-flight energy resolution is explored using a Geant4-based Monte Carlo. Our results indicate that, with the expected detector response of our system, we will be able to determine the molar density of all four elements to within a 20–30% accuracy in a two hour scan time. In many cases this error is systematically low, thus the ratio between elements is more accurate. This degree of accuracy is enough to distinguish, for example, a sample of water from a sample of pure hydrogen peroxide: the ratio of oxygen to hydrogen is reconstructed to within 8±0.5% of the true value. Lastly, with future algorithm development that accounts for backgrounds caused by scattering within the sample itself, the accuracy of molar densities, not ratios, may improve to the 5–10% level for a two hour scan time.

  3. Light-emitting diodes at 940nm attenuate colitis-induced inflammatory process in mice.

    PubMed

    Belém, Mônica O; de Andrade, Giovana M M; Carlos, Thalita M; Guazelli, Carla F S; Fattori, Victor; Toginho Filho, Dari O; Dias, Ivan F L; Verri, Waldiceu A; Araújo, Eduardo J A

    2016-09-01

    Inflammatory bowel disease (IBD) presents intense inflammatory infiltrate, crypt abscesses, ulceration and even loss of function. Despite the clinical relevance of IBD, its current therapy remains poorly effective. Infrared wavelength phototherapy shows therapeutic potential on inflammation. Our goal was to evaluate whether light-emitting diodes (LED) at 940nm are capable of mitigating the colitis-induced inflammatory process in mice. Forty male Swiss mice were assigned into five groups: control; control treated with LED therapy; colitis without treatment; colitis treated with LED therapy; colitis treated with Prednisolone. Experimental colitis was induced by acetic acid 7.5% (pH2.5) rectal administration. LED therapy was performed with light characterized by wavelength of 940nm, 45nm bandwidth, intensity of 4.05J/cm(2), total power of 270mW and total dose of 64.8J for 4min in a single application. Colitis-induced intestinal transit delay was inhibited by LED therapy. Colitis caused an increase of colon dimensions (length, diameter, total area) and colon weight (edema), which were inhibited by LED therapy. LED therapy also decreased colitis-induced tissue gross lesion, myeloperoxidase activity, microscopic tissue damage score and the presence of inflammatory infiltrate in all intestinal layers. Furthermore, LED therapy inhibited colitis-induced IL-1β, TNF-α, and IL-6 production. We conclude LED therapy at 940nm inhibited experimental colitis-induced colon inflammation in mice, therefore, rendering it a promising therapeutic approach that deserves further investigation.

  4. Influence of forward and multiple light scatter on the measurement of beam attenuation in highly scattering marine environments.

    PubMed

    Piskozub, Jacek; Stramski, Dariusz; Terrill, Eric; Melville, W Kendall

    2004-08-20

    Using three-dimensional Monte Carlo radiative transfer simulations, we examine the effect of beam transmissometer geometry on the relative error in the measurement of the beam-attenuation coefficient in an aquatic environment characterized by intense light scattering, especially within submerged bubble clouds entrained by surface-wave breaking. We discuss the forward-scattering error associated with the detection of photons scattered at small angles (< 1 degrees) and the multiple-scattering error associated with the detection of photons scattered more than once along the path length of the instrument. Several scattering phase functions describing bubble clouds at different bubble void fractions in the water are considered. Owing to forward-scattering error, a beam-attenuation meter (beam transmissometer) with a half-angle of receiver acceptance of 1.0 degrees and a path length of 0.1 m can underestimate the true beam attenuation within the bubble cloud by more than 50%. For bubble clouds with a beam attenuation of as much as 100 m(-1), the multiple-scattering error is no more than a few percent. These results are compared with simulations for some example phase functions that are representative of other scattering regimes found in natural waters. The forward-scattering error for the Petzold phase function of turbid waters is 16% for a typical instrument geometry, whereas for the Henyey-Greenstein phase function with the asymmetry parameter of 0.7 and 0.9 the error range is 8-28%.

  5. Fish oil supplementation attenuates changes in plasma lipids caused by dexamethasone treatment in rats.

    PubMed

    Barbosa, Amanda Marreiro; Francisco, Priscila de Cássia; Motta, Katia; Chagas, Thayz Rodrigues; Dos Santos, Cristiane; Rafacho, Alex; Nunes, Everson Araújo

    2016-04-01

    Dexamethasone is an anti-inflammatory glucocorticoid that may alter glucose and lipid homeostasis when administered in high doses or for long periods of time. Omega-3 fatty acids, present in fish oil (FO), can be used as potential modulators of intermediary glucose and lipid metabolism. Herein, we evaluate the effects of FO supplementation (1 g·kg(-1) body weight (BW)) on glucose and lipid metabolism in rats treated with dexamethasone (0.5 mg·kg(-1) BW) for 15 days. Adult male Wistar rats were distributed among 4 groups: control (saline, 1 mL·kg(-1) BW and mineral oil, 1 g·kg(-1) BW), DEX (dexamethasone and mineral oil), FO (fish oil and saline), and DFO (fish oil and dexamethasone). Dexamethasone and saline were administered intraperitoneally, and fish oil and mineral oil were administered by gavage. We evaluated functional and molecular parameters of lipid and glycemic profiles at 8 days and at the end of treatment. FO supplementation increased hepatic docosahexaenoic acid (DEX: 5.6% ± 0.7%; DFO: 10.5% ± 0.8%) and eicosapentaenoic acid (DEX: 0.3% ± 0.0%; DFO: 1.3% ± 0.1%) contents and attenuated the increase of plasma triacylglycerol, total cholesterol, and non-high-density lipoprotein cholesterol concentrations in DFO rats compared with DEX rats. These effects seem not to depend on hepatic expression of insulin receptor substrate 1, protein kinase B, peroxisome proliferator-activated receptor γ coactivator 1-α, and peroxisome proliferator-activated receptor γ. There was no effect of supplementation on body weight loss, fasting glycemia, and glucose tolerance in rats treated with dexamethasone. In conclusion, we show that FO supplementation for 15 days attenuates the dyslipidemia induced by dexamethasone treatment.

  6. The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: Why fine-grained terrestrial sediment is bad for coral reef ecosystems

    NASA Astrophysics Data System (ADS)

    Storlazzi, Curt D.; Norris, Ben K.; Rosenberger, Kurt J.

    2015-09-01

    Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

  7. The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: why fine-grained terrestrial sediment is bad for coral reef ecosystems

    USGS Publications Warehouse

    Storlazzi, Curt; Norris, Benjamin; Rosenberger, Kurt

    2015-01-01

    Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

  8. Light attenuates lipid accumulation while enhancing cell proliferation and starch synthesis in the glucose-fed oleaginous microalga Chlorella zofingiensis

    PubMed Central

    Chen, Tianpeng; Liu, Jin; Guo, Bingbing; Ma, Xiaonian; Sun, Peipei; Liu, Bin; Chen, Feng

    2015-01-01

    The objective of this study was to investigate the effect of light on lipid and starch accumulation in the oleaginous green algae Chlorella zofingiensis supplemented with glucose. C. zofingiensis, when fed with 30 g/L glucose, synthesized lipids up to 0.531 g/g dry weight; while in the presence of light, the lipid content dropped down to 0.352 g/g dry weight. Lipid yield on glucose was 0.184 g/g glucose, 14% higher than that cultured with light. The light-mediated lipid reduction was accompanied by the down-regulation of fatty acid biosynthetic genes at the transcriptional level. Furthermore, light promoted cell proliferation, starch accumulation, and the starch yield based on glucose. Taken together, light may attenuate lipid accumulation, possibly through the inhibition of lipid biosynthetic pathway, leading to more carbon flux from glucose to starch. This study reveals the dual effects of light on the sugar-fed C. zofingiensis and provides valuable insights into the possible optimization of algal biomass and lipid production by manipulation of culture conditions. PMID:26442783

  9. Light attenuates lipid accumulation while enhancing cell proliferation and starch synthesis in the glucose-fed oleaginous microalga Chlorella zofingiensis.

    PubMed

    Chen, Tianpeng; Liu, Jin; Guo, Bingbing; Ma, Xiaonian; Sun, Peipei; Liu, Bin; Chen, Feng

    2015-10-07

    The objective of this study was to investigate the effect of light on lipid and starch accumulation in the oleaginous green algae Chlorella zofingiensis supplemented with glucose. C. zofingiensis, when fed with 30 g/L glucose, synthesized lipids up to 0.531 g/g dry weight; while in the presence of light, the lipid content dropped down to 0.352 g/g dry weight. Lipid yield on glucose was 0.184 g/g glucose, 14% higher than that cultured with light. The light-mediated lipid reduction was accompanied by the down-regulation of fatty acid biosynthetic genes at the transcriptional level. Furthermore, light promoted cell proliferation, starch accumulation, and the starch yield based on glucose. Taken together, light may attenuate lipid accumulation, possibly through the inhibition of lipid biosynthetic pathway, leading to more carbon flux from glucose to starch. This study reveals the dual effects of light on the sugar-fed C. zofingiensis and provides valuable insights into the possible optimization of algal biomass and lipid production by manipulation of culture conditions.

  10. A circulating ghrelin mimetic attenuates light-induced phase delay of mice and light-induced Fos expression in the suprachiasmatic nucleus of rats.

    PubMed

    Yi, Chun-Xia; Challet, Etienne; Pévet, Paul; Kalsbeek, Andries; Escobar, Carolina; Buijs, Ruud M

    2008-04-01

    Anatomical evidence suggests that the ventromedial arcuate nucleus (vmARC) is a route for circulating hormonal communications to the suprachiasmatic nucleus (SCN). Whether this vmARC-SCN connection is involved in the modulation of circadian activity of the SCN is not yet known. We recently demonstrated, in rats, that intravenous (i.v.) injection of a ghrelin mimetic, GHRP-6, during the daytime activated neurons in the vmARC and reduced the normal endogenous daytime Fos expression in the SCN. In the present study we show that i.v. administration of GHRP-6 decreases light-induced Fos expression at ZT13 in the rat SCN by 50%, indicating that light-induced changes in the SCN Fos expression can also be reduced by GHRP-6. Because it is difficult to study light-induced phase changes in rats, we examined the functional effects of GHRP-6 on light-induced phase shifts in mice and demonstrated that peripherally injected GHRP-6 attenuates light-induced phase delays at ZT13 by 45%. However, light-induced Fos expression in the mice SCN was not blocked by GHRP-6. These results illustrate that acute stimulation of the ghrelinergic system may modulate SCN activity, but that its effect on light-induced phase shifts and Fos expression in the SCN might be species related.

  11. A new parameterization for surface ocean light attenuation in Earth System Models: assessing the impact of light absorption by colored detrital material

    NASA Astrophysics Data System (ADS)

    Kim, G. E.; Pradal, M.-A.; Gnanadesikan, A.

    2015-03-01

    Light limitation can affect the distribution of biota and nutrients in the ocean. Light absorption by colored detrital material (CDM) was included in a fully coupled Earth System Model using a new parameterization for shortwave attenuation. Two model runs were conducted, with and without light attenuation by CDM. In a global average sense, greater light limitation associated with CDM increased surface chlorophyll, biomass and nutrients together. These changes can be attributed to the movement of biological productivity higher up the water column, which increased surface chlorophyll and biomass while simultaneously decreasing total biomass. Meanwhile, the reduction in biomass resulted in greater nutrient availability throughout the water column. Similar results were found on a regional scale in an analysis of the oceans by biome. In coastal regions, surface chlorophyll increased by 35% while total integrated phytoplankton biomass diminished by 18%. The largest relative increases in modeled surface chlorophyll and biomass in the open ocean were found in the equatorial biomes, while largest decreases in depth-integrated biomass and chlorophyll were found in the subpolar and polar biomes. This mismatch of surface and subsurface trends and their regional dependence was analyzed by comparing the competing factors of diminished light availability and increased nutrient availability on phytoplankton growth in the upper 200 m. Overall, increases in surface biomass were expected to accompany greater nutrient uptake and therefore diminish surface nutrients, but changes in light limitation decoupled trends between these two variables. Understanding changes in biological productivity requires both surface and depth-resolved information. Surface trends may be minimal or of the opposite sign to depth-integrated amounts, depending on the vertical structure of phytoplankton abundance.

  12. Attenuation of N-glycosylation causes polarity and adhesion defects in the C. elegans embryo.

    PubMed

    Stevens, Julia; Spang, Anne

    2017-04-01

    The Caenorhabditiselegans early embryo is highly polarized, requiring sequestration of cytoplasmic polarity factors at the plasma membrane. This compartmentalization aids asymmetric distribution of lipids and proteins, which is partially responsible for the fates of the daughter cells. Since most plasma membrane proteins are glycosylated, we determined the effect of attenuation of N-glycosylation on cell polarity. While polarity establishment was not perturbed, the size difference between the two cells formed in first cell division (AB and P1) was more variable in embryos with reduced N-glycosylation than in the mock-treated embryos. In addition, among other deficiencies, we observed spindle orientation defects in two-cell embryos. Moreover, cell-cell adhesion was specifically lost at the two-cell stage when N-glycosylation was reduced. This loss-of-adhesion phenotype was rescued by interfering with polarity establishment, indicating that polarity establishment enforces plasma membrane compartmentalization. Consistent with this idea, the decreased plasma membrane levels of the adhesion proteins E-cadherin and MAGI-1 in ribo-1(RNAi) embryos were restored in the absence of functional PAR-2. Our data suggest a general role for N-glycosylation in plasma membrane compartmentalization and cell polarity.

  13. Vapor intrusion attenuation factors relative to subslab and source, reconsidered in light of background data.

    PubMed

    Yao, Yijun; Wu, Yun; Suuberg, Eric M; Provoost, Jeroen; Shen, Rui; Ma, Jianqing; Liu, Jing

    2015-04-09

    The basis upon which recommended attenuation factors for vapor intrusion (VI) have been derived are reconsidered. By making a fitting curve to the plot showing the dependence of observed indoor air concentration (c(in)) on subslab concentration (c(ss)) for residences in EPA database, an analytical equation is obtained to identify the relationship among c(in), css and the averaged background level. The new relationship indicates that subslab measurements may serve as a useful guide only if c(ss) is above 500 μg/m(3). Otherwise, c(in) is independent of c(ss), with a distribution in good agreements with other studies of background levels. Therefore, employing this screening value (500 μg/m(3)), new contaminant concentration attenuation factors are proposed for VI, and the values for groundwater-to-indoor and subslab-to-indoor air concentration attenuation factors are 0.004 and 0.02, respectively. The former is applied to examining the reported temporal variations of c(in) obtained during a long-term monitoring study. The results show that using this new groundwater-to-indoor air concentration attenuation factor also provides a reasonably conservative estimate of c(in).

  14. Vapor intrusion attenuation factors relative to subslab and source, reconsidered in light of background data

    PubMed Central

    Yao, Yijun; Wu, Yun; Suuberg, Eric M.; Provoost, Jeroen; shen, Rui; Ma, Jianqing; Liu, Jing

    2016-01-01

    The basis upon which recommended attenuation factors for vapor intrusion (VI) have been derived are reconsidered. By making a fitting curve to the plot showing the dependence of observed indoor air concentration (cin) on subslab concentration (css) for residences in EPA database, an analytical equation is obtained to identify the relationship among cin, css and the averaged background level. The new relationship indicates that subslab measurements may serve as a useful guide only if css is above 500 μg / m3. Otherwise, cin is independent of css, with a distribution in good agreements with other studies of background levels. Therefore, employing this screening value (500 μg / m3), new contaminant concentration attenuation factors are proposed for VI, and the values for groundwater-to-indoor and subslab-to-indoor air concentration attenuation factors are 0.004 and 0.02, respectively. The former is applied to examining the reported temporal variations of cin obtained during a long-term monitoring study. The results show that using this new groundwater-to-indoor air concentration attenuation factor also provides a reasonably conservative estimate of cin. PMID:25618001

  15. UV ATTENUATION NEAR CORAL REEFS IN THE FLORIDA KEYS: LIGHT ABSORPTION BY CDOM AND PARTICLES

    EPA Science Inventory

    We have investigated the roles of chromophoric dissolved organic matter (CDOM) and suspended particles in the attenuation of UV radiation in the middle and lower regions of the Florida Keys. Extended exposure to UV radiation, along with elevated sea surface temperatures, impairs...

  16. Tetramethylpyrazine attenuates carbon tetrachloride-caused liver injury and fibrogenesis and reduces hepatic angiogenesis in rats.

    PubMed

    Zhao, Shifeng; Zhang, Zili; Qian, Linnan; Lin, Qiuyi; Zhang, Chenxi; Shao, Jiangjuan; Zhang, Feng; Zheng, Shizhong

    2017-02-01

    Liver fibrosis represents a frequent event following chronic insult to trigger wound healing reactions with abnormalities of angiogenesis in the liver. Capillarization of liver sinusoidal endothelial cell (LSEC) is the pivotal event during liver angiogenesis. In the current study, we sought to investigate the effect of tetramethylpyrazine (TMP) on carbon tetrachloride (CCl4)-induced liver injury and fibrosis in rats, and to further examine the molecular mechanisms of TMP-induced anti-angiogenic effect. We found that TMP significantly ameliorated histopathological feature of liver fibrosis characterized by decreased collagen deposition, hepatocyte apoptosis, and expression of biochemical indicators, such as aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP). Moreover, TMP appeared to play an essential role in controlling pathological angiogenesis. In addition, TMP attenuated angiogenesis by downregulation of vascular endothelial growth factor-A (VEGF-A), vascular endothelial growth factor receptor 2 (VEGF-R2), platelet-derived growth factor-BB (PDGF-BB), and platelet-derived growth factor-β receptor (PDGF-βR), four important factors transmitting pro-angiogenic pathways. Besides, TMP inhibited LSEC capillarization in CCl4-induced liver fibrotic model with the morphological features of increasing sinusoidal fenestrae. Importantly, we found that disruption of angiogenesis is required for TMP to inhibit hepatocyte apoptosis in rats. Treatment with TMP significantly inhibited the expression of Bax, and up-regulated Bcl-2 expression. Interestingly, treatment with angiogenesis-inducer AngII dramatically eliminated the effect of TMP on Bax/Bcl-2 axis. Overall, these results provide novel perspectives to reveal the protective effect of TMP on liver, opening up the possibility of using TMP based anti-angiogenic drugs for the liver diseases.

  17. Transformations of Gaussian Light Beams Caused by Reflection in FEL (free Electron Lasers) Resonators

    DTIC Science & Technology

    1988-10-27

    il FILE COPy Naval Research Laboratory Washingon, DC 20375-500 NRL Memorandum Report 6347 ,qJ. o Transformations of Gaussian Light Beams N Caused by...Transformations of 7aussian Light Beams Caused by Reflection in FEL Resonators 12 PERSONAL AUTHOR(S) Riyopoulos,* S., Tang, C.M. and Sprangle, P...34 𔃾-6603 -"I, -,’ SECURITY CLASSIFICATION OF THIS PAGE 19. ABSTRACTS (Continued) cross-coupling among vector components of the radiation field, caused

  18. Absence of Protoheme IX Farnesyltransferase CtaB Causes Virulence Attenuation but Enhances Pigment Production and Persister Survival in MRSA

    PubMed Central

    Xu, Tao; Han, Jian; Zhang, Jia; Chen, Jiazhen; Wu, Nan; Zhang, Wenhong; Zhang, Ying

    2016-01-01

    The membrane protein CtaB in S. aureus is a protoheme IX farnesyltransferase involved in the synthesis of the heme containing terminal oxidases of bacterial respiratory chain. In this study, to assess the role of CtaB in S. aureus virulence, pigment production, and persister formation, we constructed a ctaB mutant in the methicillin-resistant Staphylococcus aureus (MRSA) strain USA500. We found that deletion of ctaB attenuated growth and virulence in mice but enhanced pigment production and formation of quinolone tolerant persister cells in stationary phase. RNA-seq analysis showed that deletion of ctaB caused decreased transcription of several virulence genes including RNAIII which is consistent with its virulence attenuation. In addition, transcription of 20 ribosomal genes and 24 genes involved in amino acid biosynthesis was significantly down-regulated in the ctaB knockout mutant compared with the parent strain. These findings suggest the importance of heme biosynthesis in virulence and persister formation of S. aureus. PMID:27822202

  19. EGFR-TKI, erlotinib, causes hypomagnesemia, oxidative stress, and cardiac dysfunction: attenuation by NK-1 receptor blockade.

    PubMed

    Mak, I Tong; Kramer, Jay H; Chmielinska, Joanna J; Spurney, Christopher F; Weglicki, William B

    2015-01-01

    To determine whether the epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib may cause hypomagnesemia, inflammation, and cardiac stress, erlotinib was administered to rats (10 mg · kg(-1)· d(-1)) for 9 weeks. Plasma magnesium decreased progressively between 3 and 9 weeks (-9% to -26%). Modest increases in plasma substance P (SP) occurred at 3 (27%) and 9 (25%) weeks. Neutrophil superoxide-generating activity increased 3-fold, and plasma 8-isoprostane rose 210%, along with noticeable appearance of cardiac perivascular nitrotyrosine. The neurokinin-1 (NK-1) receptor antagonist, aprepitant (2 mg · kg(-1) · d(-1)), attenuated erlotinib-induced hypomagnesemia up to 42%, reduced circulating SP, suppressed neutrophil superoxide activity and 8-isoprostane elevations; cardiac nitrotyrosine was diminished. Echocardiography revealed mild to moderately decreased left ventricular ejection fraction (-11%) and % fractional shortening (-17%) by 7 weeks of erlotinib treatment and significant reduction (-17.5%) in mitral valve E/A ratio at week 9 indicative of systolic and early diastolic dysfunction. Mild thinning of the left ventricular posterior wall suggested early dilated cardiomyopathy. Aprepitant completely prevented the erlotinib-induced systolic and diastolic dysfunction and partially attenuated the anatomical changes. Thus, chronic erlotinib treatment does induce moderate hypomagnesemia, triggering SP-mediated oxidative/inflammation stress and mild-to-moderate cardiac dysfunction, which can largely be corrected by the administration of the SP receptor blocker.

  20. Acoustical Scattering, Propagation, and Attenuation Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake

    DTIC Science & Technology

    2012-09-30

    Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake Kelly J. Benoit-Bird College of Oceanic and Atmospheric Sciences 104...Abundant Pacific Schooling Species: Humboldt Squid and Hake 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...with maximum lengths of up to 90 cm. A more recent immigrant to these waters, is the similarly sized and highly abundant jumbo or Humboldt squid

  1. Glycyrrhizic Acid Can Attenuate Metabolic Deviations Caused by a High-Sucrose Diet without Causing Water Retention in Male Sprague-Dawley Rats

    PubMed Central

    Fernando, Hamish Alexander; Chandramouli, Chanchal; Rosli, Dayang; Lam, Yi Lyn; Yong, Sheau Ting; Yaw, Hui Ping; Ton, So Ha; Kadir, Khalid Abdul; Sainsbury, Amanda

    2014-01-01

    Glycyrrhizic acid (GA) ameliorates many components of the metabolic syndrome, but its potential therapeutic use is marred by edema caused by inhibition of renal 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2). We assessed whether 100 mg/kg per day GA administered orally could promote metabolic benefits without causing edema in rats fed on a high-sucrose diet. Groups of eight male rats were fed on one of three diets for 28 days: normal diet, a high-sucrose diet, or a high-sucrose diet supplemented with GA. Rats were then culled and renal 11β-HSD2 activity, as well as serum sodium, potassium, angiotensin II and leptin levels were determined. Histological analyses were performed to assess changes in adipocyte size in visceral and subcutaneous depots, as well as hepatic and renal tissue morphology. This dosing paradigm of GA attenuated the increases in serum leptin levels and visceral, but not subcutaneous adipocyte size caused by the high-sucrose diet. Although GA decreased renal 11β-HSD2 activity, it did not affect serum electrolyte or angiotensin II levels, indicating no onset of edema. Furthermore, there were no apparent morphological changes in the liver or kidney, indicating no toxicity. In conclusion, it is possible to reap metabolic benefits of GA without edema using the current dosage and treatment time. PMID:25375630

  2. Influence of Forward and Multiple Light Scatter on the Measurement of Beam Attenuation in Highly Scattering Marine Environments

    NASA Astrophysics Data System (ADS)

    Piskozub, Jacek; Stramski, Dariusz; Terrill, Eric; Melville, W. Kendall

    2004-08-01

    Using three-dimensional Monte Carlo radiative transfer simulations, we examine the effect of beam transmissometer geometry on the relative error in the measurement of the beam-attenuation coefficient in an aquatic environment characterized by intense light scattering, especially within submerged bubble clouds entrained by surface-wave breaking. We discuss the forward-scattering error associated with the detection of photons scattered at small angles (< 1°) and the multiple-scattering error associated with the detection of photons scattered more than once along the path length of the instrument. Several scattering phase functions describing bubble clouds at different bubble void fractions in the water are considered. Owing to forward-scattering error, a beam-attenuation meter (beam transmissometer) with a half-angle of receiver acceptance of 1.0° and a path length of 0.1 m can underestimate the true beam attenuation within the bubble cloud by more than 50%. For bubble clouds with a beam attenuation of as much as 100 m^-1, the multiple-scattering error is no more than a few percent. These results are compared with simulations for some example phase functions that are representative of other scattering regimes found in natural waters. The forward-scattering error for the Petzold phase function of turbid waters is 16% for a typical instrument geometry, whereas for the Henyey-Greenstein phase function with the asymmetry parameter of 0.7 and 0.9 the error range is 8-28%.

  3. A DltA mutant of Haemophilus ducreyi Is partially attenuated in its ability to cause pustules in human volunteers.

    PubMed

    Janowicz, Diane; Leduc, Isabelle; Fortney, Kate R; Katz, Barry P; Elkins, Christopher; Spinola, Stanley M

    2006-02-01

    Haemophilus ducreyi produces two outer membrane proteins, called DltA (H. ducreyi lectin A) and DsrA (H. ducreyi serum resistance A), that contribute to the ability of the organism to evade complement-mediated serum killing. In contrast to their isogenic parent strain, 35000HP, the DsrA mutant FX517 exhibits 0% survival in 50% normal human serum and the DltA mutant FX533 exhibits 23% survival. Compared to 35000HP, FX517 does not cause pustule formation in human volunteers. To test whether DltA was required for virulence in humans, seven volunteers were experimentally infected with 35000HP and FX533. Four subjects were inoculated with fixed doses of 35000HP (101 CFU or 130 CFU) at three sites on one arm and escalating doses of FX533 (range, 46 CFU to 915 CFU) at three sites on the other arm. Pustules only developed at mutant-injected sites at doses nearly twofold higher than that of the parent, suggesting that FX533 was partially attenuated. Three subjects were inoculated with similar doses of the parent (67 CFU) and mutant (104 CFU) at three sites. Pustules formed at five of nine parent sites and one of nine mutant sites. Overall, the papule and pustule formation rates for 35000HP and FX533 were similar for the trial. However, for the five subjects who received similar doses of the parent and mutant, pustules developed at 7 of 15 sites (46.7%; 95% confidence interval [CI], 16.9% to 76.5%) inoculated with the parent and at 1 of 15 (6.7%; 95% CI, 0.1% to 18.4%) sites inoculated with the mutant (P = 0.043). We concluded that the DltA mutant was attenuated in its ability to cause disease at doses similar to that of the parent.

  4. A Reduced Zinc Diet or Zinc Transporter 3 Knockout Attenuate Light Induced Zinc Accumulation and Retinal Degeneration△

    PubMed Central

    Bai, Shi; Sheline, Carolyn R.; Zhou, Yongdong; Sheline, Christian T.

    2013-01-01

    Our previous study on retinal light exposure suggests the involvement of zinc (Zn2+) toxicity in the death of RPE and photoreceptors (LD) which could be attenuated by pyruvate and nicotinamide, perhaps through restoration of NAD+ levels. In the present study, we examined Zn2+ toxicity, and the effects of NAD+ restoration in primary retinal cultures. We then reduced Zn2+ levels in rodents by reducing Zn2+ levels in the diet, or by genetics and measured LD. Sprague Dawley albino rats were fed 2, or 61 mg Zn2+/kg of diet for 3 weeks, and exposed to 18 kLux of white light for 4h. We light exposed (70 kLux of white light for 50h) Zn2+ transporter 3 knockout (ZnT3-KO, no synaptic Zn2+), or RPE65 knockout mice (RPE65-KO, lack rhodopsin cycling), or C57/BI6/J controls and determined light damage and Zn2+ staining. Retinal Zn2+ staining was examined at 1h and 4h after light exposure. Retinas were examined after 7d by optical coherence tomography and histology. After LD, rats fed the reduced Zn2+ diet showed less photoreceptor Zn2+ staining and degeneration compared to a normal Zn2+ diet. Similarly, ZnT3-KO and RPE65-KO mice showed less Zn2+ staining, NAD+ loss, and RPE or photoreceptor death than C57/BI6/J control mice. Dietary or ZnT3-dependent Zn2+ stores, and intracellular Zn2+ release from rhodopsin recycling are suggested to be involved in light-induced retinal degeneration. These results implicate novel rhodopsin-mediated mechanisms and therapeutic targets for LD. Our companion manuscript demonstrates that pharmacologic, circadian, or genetic manipulations which maintain NAD+ levels reduce LD. PMID:23274584

  5. Attenuation by creatine of myocardial metabolic stress in Brattleboro rats caused by chronic inhibition of nitric oxide synthase.

    PubMed Central

    Constantin-Teodosiu, D.; Greenhaff, P. L.; Gardiner, S. M.; Randall, M. D.; March, J. E.; Bennett, T.

    1995-01-01

    1. The present experiment was undertaken to investigate: (a) the effect of nitric oxide synthase (NOS) inhibition, mediated by oral supplementation of the NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), on measures of myocardial energy metabolism and function: (b) the effect of oral creatine supplementation on these variables, in the absence and presence of L-NAME. 2. In one series of experiments, 4 weeks oral administration of L-NAME (0.05 mg ml-1 day-1 in the drinking water) to Brattleboro rats caused significant reductions in myocardial ATP, creatine, and total creatine concentrations and an accumulation of tissue lactate when compared with control animals. Administration of creatine (0.63 mg ml-1 day-1 in the drinking water) for 4 weeks elevated myocardial creatine and total creatine concentrations and reduced lactate accumulation, but did not significantly affect ATP or phosphocreatine (PCr). Concurrent treatment with creatine and L-NAME prevented the reduction in creatine and total creatine concentrations, and significantly attenuated the accumulation of lactate and the reduction in ATP seen with L-NAME alone. 3. In a second series of experiments, 4 weeks treatment with L-NAME and creatine plus L-NAME increased mean arterial blood pressure in conscious Brattleboro rats. Hearts isolated from these animals showed decreased coronary flow and left ventricular developed pressure (LVDP), and total mechanical performance. Treatment with creatine alone had no measurable effect on either mean arterial blood pressure or coronary flow in isolated hearts. However, there was an increase in LVDP, but not in total mechanical performance, because there was a bradycardia. 4. These results indicate that creatine supplementation can attenuate the metabolic stress associated with L-NAME administration and that this effect occurs as a consequence of the action of creatine on myocardial energy metabolism. PMID:8719809

  6. Weekly administration of paclitaxel attenuated rectal stenosis caused by multiple peritoneal recurrence 8 years after the resection of gastric carcinoma.

    PubMed

    Sakurai, Yoichi; Yoshida, Ikuo; Tonomura, Shuhei; Sakai, Wakana; Nakamura, Yasuko; Imazu, Hiroki; Matsubara, Toshiki; Ochiai, Masahiro

    2003-01-01

    We report a patient with rectal stenosis caused by peritoneal recurrence 8 years after a curative resection of advanced stage gastric carcinoma; the recurrence was effectively treated with the weekly administration of paclitaxel. The patient was a 66-year-old Japanese woman who was admitted to our hospital complaining of abdominal pain and frequent bowel movements. She had undergone total gastrectomy, due to advanced-stage gastric carcinoma with extensive lymph node metastasis, 8 years before, and had taken an oral anticancer agent, fluoropyrimidine, for 4 years after the operation. Colonofiberscopy performed on admission revealed circumferential rectal stenosis located 10 cm from the anal verge. Barium enema study demonstrated extensive poor expansion of the upper and lower rectum and irregularity of the descending colon. Abdominal computed tomography (CT) scanning revealed wall thickening in the rectum and descending colon. These findings were compatible with rectal stenosis caused by the peritoneal recurrence of gastric carcinoma. Weekly administration of paclitaxel was started. The abdominal symptoms soon disappeared when the second cycle of paclitaxel was completed, and they have not appeared since then. The rectal stenosis was attenuated, as confirmed by imaging analyses. Weekly paclitaxel has been effective for more than 13 months, suggesting that the patient is in a state of tumor dormancy of recurrent gastric carcinoma.

  7. Light spectrum regulates cell accumulation during daytime in the raphidophyte Chattonella antiqua causing noxious red tides.

    PubMed

    Shikata, Tomoyuki; Matsunaga, Shigeru; Kuwahara, Yusuke; Iwahori, Sho; Nishiyama, Yoshitaka

    2016-07-01

    Most marine raphidophyte species cause noxious red tides in temperate coastal areas around the world. It is known that swimming abilities enable raphidophytes to accumulation of cells and to actively acquire light at surface layers and nutrients over a wide depth range. However, it remains unclear how the swimming behavior is affected by environmental conditions, especially light condition. In the present study, we observed the accumulation of the harmful red-tide raphidophyte Chattonella antiqua under various light conditions during the daytime in the laboratory. When exposed to ultraviolet-A/blue light (320-480nm) or red light (640-680nm) from above, cells moved downward. In the case of blue light (455nm), cells started to swim downward after 5-15min of irradiation at a photon flux density≥10μmolm(-2)s(-1). When exposed to monochromatic lights (400-680nm) from the side, cells moved away from the blue light source and then descended, but just moved downward under red light. However, mixing of green/orange light (520-630nm) diminished the effects of blue light. When exposed to a mixture of 30μmolm(-2)s(-1) of blue light (440nm) and ≥6μmolm(-2)s(-1) of yellow light (560nm) from above, cells did not move downward. These results indicate that blue light induces negative phototaxis and ultraviolet-A/blue and red lights induce descending, and green/orange light cancels out their effects in C. antiqua.

  8. [Non-amyloidotic glomerular disease caused by light-chain deposits: a case report].

    PubMed

    Cantillo, Jorge de Jesús; López, Rocío del Pilar; Andrade, Rafael Enrique

    2009-12-01

    The nephropathy of monoclonal gammopathies is principally caused by light chain deposits of fragmented immunoglobins. Paraprotein-related renal diseases are associated with such deposits of intact (heavy chain) or fragmentary (light chain) immunoglobins. A condition of pathological light chain deposits is rare and characterized by deposits of fragments of monoclonal immunoglobulins in many organs. Renal deposits occur primarily in glomeruli and tubular basement membranes. This disease is frequently associated with lymphoproliferative disorders. The majority of cases are caused by deposits of kappa light chains. Whereas this disease is most frequently associated with hematologic malignancies, occasionally a case occurs without detectable hematological pathologies; these cases are called idiopathic or primary. They usually manifest themselves as severe renal insufficiencies with nephrotic-range proteinuria. No treatment regime has been clearly established and the prognosis is poor. Herein, the clinical and histological characteristics are described regarding the first case in Colombia of light chain deposit disease without symptoms of malignancy.

  9. Summary of oceanographic measurements for characterizing light attenuation and sediment resuspension in the Barnegat Bay-Little Egg Harbor Estuary, New Jersey, 2013

    USGS Publications Warehouse

    Dickhudt, Patrick J.; Ganju, Neil K.; Montgomery, Ellyn T.

    2015-08-28

    The U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection, measured suspended-sediment concentrations, currents, waves, light attenuation, and a variety of other water-quality parameters in the summer of 2013 in Barnegat Bay-Little Egg Harbor, New Jersey. These measurements quantified light attenuation and sediment resuspension in three seagrass meadows. Data were acquired sequentially at three paired channel-shoal sites, as the equipment was moved from south to north in the estuary. Data were collected for approximately 3 weeks at each site.

  10. Light-Intensity Activity Attenuates Functional Decline in Older Cancer Survivors

    PubMed Central

    Blair, Cindy K.; Morey, Miriam C.; Desmond, Renee A.; Cohen, Harvey Jay; Sloane, Richard; Snyder, Denise C.; Demark-Wahnefried, Wendy

    2014-01-01

    While moderate-vigorous intensity physical activities (MVPA) confer the greatest health benefits, evidence suggests that light-intensity activities are also beneficial, particularly for older adults and individuals with moderate-severe comorbidities. Purpose To examine cross-sectional and longitudinal associations between light-intensity activity and physical function in older cancer survivors at increased risk for age- and treatment-related comorbidities, including accelerated functional decline. Methods The analysis included data from 641 breast, prostate, and colorectal cancer survivors (54% female) aged 65 and older who participated in a 1-year, home-based diet and exercise intervention designed to reduce the rate of physical function decline. ANCOVA was used to compare means of physical function across levels of PA intensity (low-light (LLPA): 1.5-2.0 METs; high-light (HLPA): 2.1-2.9 METs; MVPA: ≥3.0 METs). Results In cross-sectional analyses, increasing tertiles of light-intensity activity were associated with higher scores for all 3 measures of physical function (all p-values <0.005), after adjustment for age, sex, BMI, comorbidity, symptoms, and MVPA. Associations were stronger for HLPA than for LLPA. Compared with survivors who decreased or remained stable in MVPA and HLPA at the post-intervention follow-up, those who increased in HLPA, but decreased or remained stable in MVPA, reported higher physical function scores (LSMeans (95% CI): SF-36 physical function subscale: -5.58 (-7.96, -3.20) vs. -2.54 (-5.83, 0.75), p=0.14; basic lower extremity function: -2.00 (-3.45, -0.55) vs. 0.28 (-1.72, 2.28), p=0.07; advanced lower extremity function: -2.58 (-4.00, -1.15) vs. 0.44 (-1.52, 2.40), p=0.01). Conclusion Our findings suggest that increasing light-intensity activities, especially HLPA, may be a viable approach to reducing the rate of physical function decline in individuals who are unable or reluctant to initiate or maintain adequate levels of moderate

  11. Detecting the Attenuation of Blazar Gamma-ray Emission by Extragalactic Background Light with GLAST

    NASA Technical Reports Server (NTRS)

    Chen, Andrew; Ritz, Steven

    1999-01-01

    Gamma rays with energy above 10 GeV interact with optical-UV photons resulting in pair production. Therefore, a large sample of high redshift sources of these gamma rays can be used to probe the extragalactic background starlight (EBL) by examining the redshift dependence of the attenuation of the flux above 10 GeV. GLAST, the next generation high-energy gamma-ray telescope, will for the first time have the unique capability to detect thousands of gamma-ray blazars up to redshifts of at least z = 4, with enough angular resolution to allow identification of a large fraction of their optical counterparts. By combining recent determinations of the gamma-ray blazar luminosity function, recent calculations of the high energy gamma-ray opacity due to EBL absorption, and the expected GLAST instrument performance to produce simulated samples of blazars that GLAST would detect, including their redshifts and fluxes, we demonstrate that these blazars have the potential to be a highly effective probe of the EBL.

  12. Lobeglitazone, a Novel Peroxisome Proliferator-Activated Receptor γ Agonist, Attenuates Renal Fibrosis Caused by Unilateral Ureteral Obstruction in Mice

    PubMed Central

    Seo, Jung Beom; Jung, Yun-A; Seo, Hye-Young; Kang, Sun Hee; Jeon, Hui-Jeon; Lee, Jae Man; Lee, Sungwoo; Kim, Jung-Guk; Lee, In-Kyu

    2017-01-01

    Background Renal tubulointerstitial fibrosis is a common feature of the final stage of nearly all cause types of chronic kidney disease. Although classic peroxisome proliferator-activated receptor γ (PPARγ) agonists have a protective effect on diabetic nephropathy, much less is known about their direct effects in renal fibrosis. This study aimed to investigate possible beneficial effects of lobeglitazone, a novel PPARγ agonist, on renal fibrosis in mice. Methods We examined the effects of lobeglitazone on renal tubulointerstitial fibrosis in unilateral ureteral obstruction (UUO) induced renal fibrosis mice. We further defined the role of lobeglitazone on transforming growth factor (TGF)-signaling pathways in renal tubulointerstitial fibrosis through in vivo and in vitro study. Results Through hematoxylin/eosin and sirius red staining, we observed that lobeglitazone effectively attenuates UUO-induced renal atrophy and fibrosis. Immunohistochemical analysis in conjunction with quantitative reverse transcription polymerase chain reaction and Western blot analysis revealed that lobeglitazone treatment inhibited UUO-induced upregulation of renal Smad-3 phosphorylation, α-smooth muscle actin, plasminogen activator inhibitor 1, and type 1 collagen. In vitro experiments with rat mesangial cells and NRK-49F renal fibroblast cells suggested that the effects of lobeglitazone on UUO-induced renal fibrosis are mediated by inhibition of the TGF-β/Smad signaling pathway. Conclusion The present study demonstrates that lobeglitazone has a protective effect on UUO-induced renal fibrosis, suggesting that its clinical applications could extend to the treatment of non-diabetic origin renal disease. PMID:28256116

  13. Restricted Inter-ocean Exchange and Attenuated Biological Export Caused Enhanced Carbonate Preservation in the PETM Ocean

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Boudreau, B. P.; Dickens, G. R.; Sluijs, A.; Middelburg, J. J.

    2015-12-01

    Carbon dioxide (CO2) release during the Paleocene-Eocene Thermal Maximum (PETM, 55.8 Myr BP) acidified the oceans, causing a decrease in calcium carbonate (CaCO3) preservation. During the subsequent recovery from this acidification, the sediment CaCO3 content came to exceed pre-PETM values, known as over-deepening or over-shooting. Past studies claim to explain these trends, but have failed to reproduce quantitatively the time series of CaCO3 preservation. We employ a simple biogeochemical model to recreate the CaCO3 records preserved at Walvis Ridge of the Atlantic Ocean. Replication of the observed changes, both shallowing and the subsequent over-deepening, requires two conditions not previously considered: (1) limited deep-water exchange between the Indo-Atlantic and Pacific oceans and (2) a ~50% reduction in the export of CaCO3 to the deep sea during acidification. Contrary to past theories that attributed over-deepening to increased riverine alkalinity input, we find that over-deepening is an emergent property, generated at constant riverine input when attenuation of CaCO3 export causes an unbalanced alkalinity input to the deep oceans (alkalinization) and the development of deep super-saturation. Restoration of CaCO3 export, particularly in the super-saturated deep Indo-Atlantic ocean, later in the PETM leads to greater accumulation of carbonates, ergo over-shooting, which returns the ocean to pre-PETM conditions over a time scale greater than 200 kyr. While this feedback between carbonate export and the riverine input has not previously been considered, it appears to constitute an important modification of the classic carbonate compensation concept used to explain oceanic response to acidification.

  14. Attenuation, scattering, and depolarization of light by gold nanorods with silver shells

    NASA Astrophysics Data System (ADS)

    Khlebtsov, B. N.; Khanadeev, V. A.; Khlebtsov, N. G.

    2010-01-01

    Gold nanoparticles with silver nanoshells are obtained by synthesizing gold nanorods in a growing solution containing cetyltrimethylammonium bromide, subsequent separation in a concentration gradient of glycerol, and reduction of silver nitrate by ascorbic acid under alkaline conditions in the presence of polyvinylpyrrolidone. The formation of silver nanoshells was monitored by the shift of plasmon resonances of extinction and differential light scattering, by the appearance of characteristics peaks of silver in the energy dispersive X-ray (EDX) spectra of samples, by the data of transmission electron microscopy, and by visual changes in the color of colloids. The spectrum of the intensity ratio of the co- and cross-polarized compo- nents of light scattered by gold-silver nanorods is measured for the first time, and it is observed that the maximum is shifted by 80-100 nm compared to previously published spectra of gold nanorods (Khlebtsov et al., J. Phys. Chem. C 112, 12760 (2008)). The extinction and light scattering spectra are calculated by the method of separation of variables using the model of a confocal two-layer spheroid and these calculations are found to agree with spectral measurements. A method for determining the thickness of a silver nanolayer by the spectral shift of an extinction longitudinal resonance is described. The obtained data of optical spectroscopy and transmission electron microscopy and estimations of the mass of the deposited metal show that the aver-age thickness of the silver layer varies from 0.12 to 4 nm as the Ag/Au ratio changes from 2/80 to 90/80 μg/μg.

  15. Attenuation of the Light Curves of the Symbiotic Binary SY Mus by Circumstellar Material

    NASA Astrophysics Data System (ADS)

    Shagatova, N.; Skopal, A.

    2017-02-01

    SY Mus is a potential precursor of the B[e]-phenomenon system. In this contribution we modeled the ultraviolet (UV) fluxes of this system at 10 wavelengths from 1280 to 3080 Å. This way we obtained the contribution to the total flux at each wavelength from a nebula and estimated the upper limit of column densities for the negative hydrogen ion in the neutral wind and the neutral hydrogen atom in the predominantly ionized wind. Most importantly, we justified that the asymmetric distribution of the wind from the red giant component accounts for the observed UV continuum light-curve asymmetry.

  16. Effect of scattering albedo on attenuation and polarization of light underwater.

    PubMed

    Cochenour, Brandon; Mullen, Linda; Muth, John

    2010-06-15

    Recent work on underwater laser communication links uses polarization discrimination to improve system performance [Appl. Opt.48, 328 (2009)] [in Proceedings of IEEE Oceans 2009 (IEEE, 2009), pp. 1-4]. In the laboratory, Maalox antacid is commonly used as a scattering agent. While its scattering function closely mimics that of natural seawaters, its scattering albedo can be much higher, as Maalox particles tend to be less absorbing. We present a series of experiments where Nigrosin dye is added to Maalox in order to more accurately recreate real-world absorption and scattering properties. We consider the effect that scattering albedo has on received power and the degree of depolarization of forward-scattered light in the context of underwater laser communication links.

  17. Enriched environment attenuates changes in water-maze performance and BDNF level caused by prenatal alcohol exposure

    PubMed Central

    Tipyasang, Rungpiyada; Kunwittaya, Sarun; Mukda, Sujira; Kotchabhakdi, Nittaya J.; Kotchabhakdi, Naiphinich

    2014-01-01

    Prenatal exposure to alcohol can result in fetal alcohol syndrome (FAS), characterized by significant changes in the physiology, structural plasticity of hippocampal function, including long-term deficits in learning and memory. Environmental enrichment has long been known to improve motor and cognitive function levels, causes several neurochemical and morphological alterations in the brain. Therefore, the effects of environmental enrichment on the neurobehavioral and neurotrophic changes in mice exposed prenatally to alcohol were investigated in this study. The pregnant dams were given 25 % ethanol (w/v) or isocaloric sucrose by liquid diet from gestation day 7 to 20. After weaning on postnatal day 28, offspring were exposed to standard cage (CC, CFAS) or enriched living conditions (CE, EFAS) for 8 weeks. Neurobehavioral studies both on hippocampus-dependent spatial learning and place and cue learning strategy, a striatum-dependent test, were measured by the Morris water maze task. Moreover, the reverse-transcriptase polymerase chain reaction (RT-PCR) technique was also used in order to study the expression of brain-derived neurotrophic factor (BDNF) level in both the hippocampus and striatum of mice. Neurobehavioral studies show that animals exposed prenatally to alcohol were impaired as shown in both hippocampal-dependent spatial/place and striatal-dependent response/cue learning tests. Moreover, the levels of BDNF expression both in the hippocampus and striatum of mice were also decreased. Interestingly, environmental enrichment can ameliorate the effects of prenatal alcohol exposure both on the neurobehavioral and neurotrophic levels. These observations indicated that enriched environment attenuated memory impairment of prenatal alcohol exposure both in hippocampal and striatal circuitry. PMID:26417281

  18. Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress.

    PubMed

    Jaiswal, Manish; Haelterman, Nele A; Sandoval, Hector; Xiong, Bo; Donti, Taraka; Kalsotra, Auinash; Yamamoto, Shinya; Cooper, Thomas A; Graham, Brett H; Bellen, Hugo J

    2015-07-01

    Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration--defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise.

  19. A global review of seabird mortality caused by land-based artificial lights.

    PubMed

    Rodríguez, Airam; Holmes, Nick D; Ryan, Peter G; Wilson, Kerry-Jayne; Faulquier, Lucie; Murillo, Yovana; Raine, André F; Penniman, Jay; Neves, Verónica; Rodríguez, Beneharo; Negro, Juan J; Chiaradia, André; Dann, Peter; Anderson, Tracy; Metzger, Benjamin; Shirai, Masaki; Deppe, Lorna; Wheeler, Jennifer; Hodum, Peter; Gouveia, Catia; Carmo, Vanda; Carreira, Gilberto P; Delgado-Alburqueque, Luis; Guerra-Correa, Carlos; Couzi, François-Xavier; Travers, Marc; Le Corre, Matthieu

    2017-02-02

    Artificial lights at night cause high mortality of seabirds, one of the most endangered groups of birds globally. Fledglings of burrow-nesting seabirds, and to a lesser extent adults, are grounded by lights when they fly at night. We review the current state of knowledge of light attraction, identify information gaps and propose measures to address the problem. Although other avian families such as Alcidae and Anatidae can be involved, the most affected seabirds are petrels and shearwaters: at least 56 species, more than one-third of them (24) threatened, are grounded by lights. Grounded seabirds have been found worldwide, mainly on oceanic islands but also at some continental locations. Petrel breeding grounds confined to formerly uninhabited islands are particularly at risk from ever-growing levels of light pollution due to tourism and urban sprawl. Where it is impractical to ban external lights, rescue programs of grounded birds offer the most immediate and extended mitigation measures to reduce light-induced mortality, saving thousands of birds every year. These programs also provide useful information for seabird management. However, the data typically are fragmentary and often strongly biased so the phenomenon is poorly understood, leading to inaccurate impact estimates. We identified as the most urgent priority actions: 1) estimation of mortality and impact on populations; 2) assessment of threshold light levels and safe distances from light sources; 3) documenting the fate of rescued birds; 4) improvement of rescue campaigns, particularly in terms of increasing recovery rates and level of care; and 5) research on seabird-friendly lights to reduce attraction. More research is necessary to improve our understanding of this human-wildlife conflict and to design effective management and mitigation measures. This article is protected by copyright. All rights reserved.

  20. Light at the interface: the potential of attenuated total reflection infrared spectroscopy for understanding heterogeneous catalysis in water.

    PubMed

    Mojet, Barbara Louise; Ebbesen, Sune Dalgaard; Lefferts, Leon

    2010-12-01

    IR spectroscopy has been an important tool for studying detailed interactions of reactants and reaction-intermediates with catalyst surfaces. Studying reactions in water is, however, far from trivial, due to the excessive absorption of infrared light by water. One way to deal with this is the use of Attenuated Total Reflection spectroscopy (ATR-IR) minimizing the path length of infrared light through the water. Moreover, ATR-IR allows for a direct comparison of reactions in gas and water on the same sample, which bridges the gap between separate catalyst investigations in gas and liquid phase. This tutorial review describes recent progress in using ATR-IR for studying heterogeneous catalysts in water. An overview is given of the important aspects to be taken into account when using ATR-IR to study heterogeneous catalysts in liquid phase, like the procedure to prepare stable catalyst layers on the internal reflection element. As a case study, CO adsorption and oxidation on noble metal catalysts is investigated with ATR-IR in gas and water. The results show a large effect of water and pH on the adsorption and oxidation of CO on Pt/Al(2)O(3) and Pd/Al(2)O(3). From the results it is concluded that water affects the metal particle potential as well as the adsorbed CO molecule directly, resulting in higher oxidation rates in water compared to gas phase. Moreover, also pH influences the metal particle potential with a clear effect on the observed oxidation rates. Finally, the future outlook illustrates that ATR-IR spectroscopy holds great promise in the field of liquid phase heterogeneous catalysis.

  1. Attenuation of UV Light in Mars Analog Minerals: Implications for Organic Detection with the SHERLOC Mars 2020 Instrument

    NASA Astrophysics Data System (ADS)

    Carrier, Brandi; Beegle, Luther; Bhartia, Rohit; Abbey, William

    2016-10-01

    SHERLOC is an instrument that is part of the Mars 2020 payload. It utilizes a deep UV laser (248.6 nm) to induce Raman and fluorescence in organics and minerals [1]. Samples of interest are spatially scanned with the laser to stimulate fluorescence emissions and Raman scattering from the sample. Specifically, fluorescence is generated from electronic transitions in aromatic organics and Raman scatter is generated from vibrational bonds in both organics and minerals [2]. SHERLOC will be used on Mars to identify, in situ, interesting samples for sample caching and potential subsequent return to Earth.The mineral transparency at the wavelengths of interest (~250-400 nm) for both the incident laser light and the sample specific photons from fluorescence emission or Raman scattering will affect the interrogation volume of analysis and thus constrain the limits of detection.The attenuation rates of UV photons in bulk mineral samples have been determined as a function of mineral layer thickness for Mojave Mars Simulant basalt (MMS), gypsum (calcium sulfate), kaolinite (a clay mineral) and Bishop Tuff (a rhyolitic tuff). UV attenuation curves were determined by placing mineral pellets of varying thickness between a 1000-W Xe arc lamp and a radiometrically calibrated UV spectrometer. Results show that although UV transmission drops off quickly as a function of depth, there is some penetration of UV photons even at depths of several hundred microns.We have also used a SHERLOC-like laser system to detect aromatic and aliphatic organics under thin layers of these minerals at different depths below the surface. Results indicate that detection of certain organics may be possible at depths of 250um or greater below the mineral surface, allowing for a greater interrogation volume than previously assumed for SHERLOC.1. Beegle, Luther et al. "SHERLOC: Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals." 2015 IEEE Aerospace Conference. IEEE, 2015. 1

  2. Differential diagnosis of pelvic cystic lesions caused by hemorrhage from inflammatory abscess using CT attenuation in women with acute abdomen.

    PubMed

    Sato, Kazuko; Kajihara, Takeshi; Miki, Akinori; Hirabayashi, Eriko; Shintani, Daisuke; Niitsu, Mamoru; Ishihara, Osamu; Itakura, Atsuo

    2015-11-01

    To determine the efficacy of computed tomography (CT) attenuation of cystic lesions measured on an image browsing system to distinguish abscess from hematoma in women with acute abdomen. The medical records of female patients of reproductive age with acute abdomen who were treated over a 7-year period in a single center and who had undergone laparotomy or laparoscopic surgery and preoperative pelvic CT scanning were retrospectively analyzed to identify those with hematoma or abscess cyst formation. Nineteen patients with tubo-ovarian abscess (abscess group) and six patients with hematoma (hematoma group) formation in the pelvis were included in the analysis. The preoperative CT images of the tubo-ovarian cyst were retrospectively investigated on the basis of cyst attenuation. CT attenuation of the cyst measured by both two gynecologists could be used to clearly distinguish inflammatory disease with abscess formation from bleeding disease with hematoma. CT attenuation on a picture archiving and communication system can distinguish hematoma from abscess in women with acute abdomen. This may significantly contribute to making differential diagnosis without interpretation by a medical radiologist.

  3. An Analysis of Diffuse Light Attenuation in the Northern Gulf of Mexico Hypoxic Zone Using the SeaWiFS Satellite Data Record

    DTIC Science & Technology

    2011-01-01

    from the Mississippi and Atchafalaya River Basin. SeaWiFS daily integrated surface photosynthetically active radiation (PAR, 400 -700 nm) and diffuse...speed, nutrient loading, and river discharge from the Mississippi and Atchafalaya River Basin. SeaWiFS daily integrated surface photosynthetically ...the hypoxic zone. In this paper we examine shelf-wide synoptic estimates of diffuse light attenuation, absolute daily integrated photosynthetically

  4. Self-attenuation artifacts and correction factors of light element measurements by X-ray analysis: Implication for mineral dust composition studies

    NASA Astrophysics Data System (ADS)

    Formenti, P.; Nava, S.; Prati, P.; Chevaillier, S.; Klaver, A.; Lafon, S.; Mazzei, F.; Calzolai, G.; Chiari, M.

    2010-01-01

    On a global scale, mineral dust is one of the major components of atmospheric aerosols and has important effects on the radiative budget of the atmosphere and thus on climate forcing. An accurate measurement of the concentration of crustal elements, namely Na, Mg, Al, Si, K, Ca, Ti, and Fe, is mandatory for the study of desert aerosols. The concentration of light elements, when measured by X-ray emission techniques such as X-ray fluorescence (XRF) and particle-induced X-ray emission (PIXE), can be underestimated owing to self-absorption of the emitted soft X-rays inside aerosol particles. In this work, we analyzed dust samples collected in field campaigns and samples produced in the laboratory using dust of known composition. Measurements have been conducted with PIXE and energy-dispersive XRF (ED-XRF), together with an attenuation-free technique such as particle-induced gamma-ray emission (PIGE) and attenuation corrected wavelength-dispersive XRF (WD-XRF) by internal standard calibration. We focus on the determination of Al and present results of a PIXE versus PIGE intercomparison. Aluminum concentration was measured with both techniques in dust samples collected by aircraft sampling over western Africa during winter 2006 and summer 2007. An underestimation of the Al concentration determined by PIXE was observed (up to 40%), and it was compared with the results of a simple calculation using basic physics and the size distribution of the collected aerosol. Similar attenuation was observed for Mg, Al, and Si in the laboratory samples analyzed by ED-XRF and WD-XRF. In order to use concentration ratios involving light elements as tracers of the region of emission of the sampled dust, these artifacts (i.e., underestimation of the concentration of light elements) induced by self-attenuation should be properly considered and corrected.

  5. Photodynamic inactivation of microorganisms which cause pulmonary diseases with infrared light: an in vitro study

    NASA Astrophysics Data System (ADS)

    Leite, Ilaiáli S.; Geralde, Mariana C.; Salina, Ana C.; Medeiros, Alexandra I.; Kurachi, Cristina; Bagnato, Vanderlei S.; Inada, Natalia M.

    2014-03-01

    Lower respiratory infections are among the leading causes of death worldwide. In this study, it was evaluated the interaction of indocyanine green, a photosensitizer activated by infrared light, with alveolar macrophages and the effectiveness of the photodynamic therapy using this compound against Streptococcus pneumoniae . Initial experiments analyzed indocyanine green toxicity to alveolar macrophages in the dark with different drug concentrations and incubation times, and macrophage viability was obtained with the MTT method. The average of the results showed viability values below 90% for the two highest concentrations. Experiments with Streptococcus pneumoniae showed photodynamic inactivation with 10 μM indocyanine green solution. Further experiments with the bacteria in co-culture with AM will be conducted verifying the photodynamic inactivation effectiveness of the tested drug concentrations and incubation periods using infrared light.

  6. Immunization with a highly attenuated replication-competent herpes simplex virus type 1 mutant, HF10, protects mice from genital disease caused by herpes simplex virus type 2.

    PubMed

    Luo, Chenhong; Goshima, Fumi; Kamakura, Maki; Mutoh, Yoshifumi; Iwata, Seiko; Kimura, Hiroshi; Nishiyama, Yukihiro

    2012-01-01

    Genital herpes is an intractable disease caused mainly by herpes simplex virus (HSV) type 2 (HSV-2), and is a major concern in public health. A previous infection with HSV type 1 (HSV-1) enhances protection against primary HSV-2 infection to some extent. In this study, we evaluated the ability of HF10, a naturally occurring replication-competent HSV-1 mutant, to protect against genital infection in mice caused by HSV-2. Subcutaneous inoculation of HF10-immunized mice against lethal infection by HSV-2, and attenuated the development of genital ulcer diseases. Immunization with HF10 inhibited HSV-2 replication in the mouse vagina, reduced local inflammation, controlled emergence of neurological dysfunctions of HSV-2 infection, and increased survival. In HF10-immunized mice, we observed rapid and increased production of interferon-γ in the vagina in response to HSV-2 infection, and numerous CD4(+) and a few CD8(+) T cells localized to the infective focus. CD4(+) T cells invaded the mucosal subepithelial lamina propria. Thus, the protective effect of HF10 was related to induction of cellular immunity, mediated primarily by Th1 CD4(+) cells. These data indicate that the live attenuated HSV-1 mutant strain HF10 is a promising candidate antigen for a vaccine against genital herpes caused by HSV-2.

  7. Quantifying the biological impact of surface ocean light attenuation by colored detrital matter in an ESM using a new optical parameterization

    NASA Astrophysics Data System (ADS)

    Kim, G. E.; Pradal, M.-A.; Gnanadesikan, A.

    2015-08-01

    Light attenuation by colored detrital material (CDM) was included in a fully coupled Earth system model (ESM). This study presents a modified parameterization for shortwave attenuation, which is an empirical relationship between 244 concurrent measurements of the diffuse attenuation coefficient for downwelling irradiance, chlorophyll concentration and light absorption by CDM. Two ESM model runs using this parameterization were conducted, with and without light absorption by CDM. The light absorption coefficient for CDM was prescribed as the average of annual composite MODIS Aqua satellite data from 2002 to 2013. Comparing results from the two model runs shows that changes in light limitation associated with the inclusion of CDM decoupled trends between surface biomass and nutrients. Increases in surface biomass were expected to accompany greater nutrient uptake and therefore diminish surface nutrients. Instead, surface chlorophyll, biomass and nutrients increased together. These changes can be attributed to the different impact of light limitation on surface productivity versus total productivity. Chlorophyll and biomass increased near the surface but decreased at greater depths when CDM was included. The net effect over the euphotic zone was less total biomass leading to higher nutrient concentrations. Similar results were found in a regional analysis of the oceans by biome, investigating the spatial variability of response to changes in light limitation using a single parameterization for the surface ocean. In coastal regions, surface chlorophyll increased by 35 % while total integrated phytoplankton biomass diminished by 18 %. The largest relative increases in modeled surface chlorophyll and biomass in the open ocean were found in the equatorial biomes, while the largest decreases in depth-integrated biomass and chlorophyll were found in the subpolar and polar biomes. This mismatch of surface and subsurface trends and their regional dependence was analyzed by

  8. A mechanism of virulence: virulent Mycobacterium tuberculosis strain H37Rv, but not attenuated H37Ra, causes significant mitochondrial inner membrane disruption in macrophages leading to necrosis.

    PubMed

    Chen, Minjian; Gan, Huixian; Remold, Heinz G

    2006-03-15

    Infection of human monocyte-derived macrophages with Mycobacterium tuberculosis at low multiplicities of infection leads 48-72 h after the infection to cell death with the characteristics of apoptosis or necrosis. Predominant induction of one or the other cell death modality depends on differences in mitochondrial membrane perturbation induced by attenuated and virulent strains. Infection of macrophages with the attenuated H37Ra or the virulent H37Rv causes mitochondrial outer membrane permeabilization characterized by cytochrome c release from the mitochondrial intermembrane space and apoptosis. Mitochondrial outer membrane permeabilization is transient, peaks 6 h after infection, and requires Ca(2+) flux and B cell chronic lymphocytic leukemia/lymphoma 2-associated protein X translocation into mitochondria. In contrast, only the virulent H37Rv induces significant mitochondrial transmembrane potential (Deltapsi(m)) loss caused by mitochondrial permeability transition. Dissipation of Deltapsi(m) also peaks at 6 h after infection, is transient, is inhibited by the classical mitochondrial permeability transition inhibitor cyclosporine A, has a requirement for mitochondrial Ca(2+) loading, and is independent of B cell chronic lymphocytic leukemia/lymphoma translocation into the mitochondria. Transient dissipation of Deltapsi(m) 6 h after infection is essential for the induction of macrophage necrosis by Mtb, a mechanism that allows further dissemination of the pathogen and development of the disease.

  9. A Nampt inhibitor FK866 mimics vitamin B3 deficiency by causing senescence of human fibroblastic Hs68 cells via attenuation of NAD(+)-SIRT1 signaling.

    PubMed

    Song, Tuzz-Ying; Yeh, Shu-Lan; Hu, Miao-Lin; Chen, Mei-Yau; Yang, Nae-Cherng

    2015-12-01

    Vitamin B3 (niacin) deficiency can cause pellagra with symptoms of dermatitis, diarrhea and dementia. However, it is unclear whether the vitamin B3 deficiency causes human aging. FK866 (a Nampt inhibitor) can reduce intracellular NAD(+) level and induce senescence of human Hs68 cells. However, the mechanisms underlying FK866-induced senescence of Hs68 cells are unclear. In this study, we used FK866 to mimic the effects of vitamin B3 deficiency to reduce the NAD(+) level and investigated the mechanisms of FK866-induced senescence of Hs68 cells. We hypothesized that FK866 induced the senescence of Hs68 cells via an attenuation of NAD(+)-silent information regulator T1 (SIRT1) signaling. We found that FK866 induced cell senescence and diminished cellular NAD(+) levels and SIRT1 activity (detected by acetylation of p53), and these effects were dramatically antagonized by co-treatment with nicotinic acid, nicotinamide, or NAD(+). In contrast, the protein expression of SIRT1, AMP-activated protein kinase, mammalian target of rapamycin, and nicotinamide phosphoribosyltransferase (Nampt) was not affected by FK866. In addition, the role of GSH in the FK866-induced cells senescence may be limited, as N-acetylcysteine did not antagonize FK866-induced cell senescence. These results suggest that FK866 induces cell senescence via attenuation of NAD(+)-SIRT1 signaling. The effects of vitamin B3 deficiency on human aging warrant further investigation.

  10. Depolarization of polarized light caused by high altitude clouds. 1: Depolarization of lidar induced by cirrus.

    PubMed

    Sun, Y Y; Li, Z P; Bösenberg, J

    1989-09-01

    A scattering model is described for the investigation of depolarization of polarized light caused by ice clouds. The scattering by a single particle is described by refraction, reflection, and diffraction. The ice cloud is assumed to be a random mixture of hexagonal columns and plates of random orientation and size. Multiple scattering effects are included by means of a Monte Carlo method, where single photon histories are constructed from random samples of the distributions governing the basic scattering parameters. The dependence of depolarization on cloud extinction coefficient, receiver field of view, and mixing ratio of columns to plates are studied. Lidar measurements of depolarization by a high altitude cirrus cloud are presented and discussed within the frame of the present model. Good agreement can be obtained assuming a variation of crystal shape distribution with height.

  11. Attenuated SIV causes persisting neuroinflammation in the absence of a chronic viral load and neurotoxic antiretroviral therapy

    PubMed Central

    Ferguson, Deborah; Clarke, Sean; Berry, Neil; Almond, Neil

    2016-01-01

    Objectives: Using simian models, where SIV chronic viral loads are naturally controlled in the absence of potentially neurotoxic therapies, we investigated the neuropathological events occurring during times of suppressed viraemia and when these events were initiated. Design: Cynomolgus macaques were infected with SIV strains that are naturally controlled to low levels of chronic viraemia. Study 1: animals were maintained up to 300 days after inoculation and analysed for viral-induced neuropathology following sustained suppression of chronic viral loads. Study 2: initiation and development of lesion was examined following 3, 10, 21, or 125 days SIVmacC8 infection. Methods: Formalin-fixed, paraffin-embedded brain sections were analysed following immunohistochemical staining for simian immunodeficiency virus (SIV) (KK41), blood–brain barrier leakage (ZO-1, fibrinogen), apoptosis (active caspase 3), neuroinflammation [GFAP, cyclooxygenase (COX)-1, COX-2], microglia and macrophage (Iba-1, CD68, and CD16), oligodendrocytes (CNPase1), MHC class II expression, and T cells (CD3 and CD8). Replicating SIV was detected through in-situ hybridization. Results: Study 1: neuroinflammation was present despite prolonged suppressed viraemia. Study 2: attenuated SIV entered the brain rapidly triggering acute phase neuroinflammatory responses. These did not return to naive levels and GFAP and COX-2 responses continued to develop during a chronic phase with a suppressed viral load. Conclusion: Neuroinflammatory responses similar to those in HIV neurocognitively impaired patients are present within macaque brains during prolonged periods of suppressed SIV viral load and in the absence of potentially neurotoxic antiretroviral drugs. These responses, initiated during acute infection, do not resolve despite the lack of on-going peripheral viraemia to potentially reseed the brain. PMID:27258396

  12. N-acetyl-heparin attenuates acute lung injury caused by acid aspiration mainly by antagonizing histones in mice.

    PubMed

    Zhang, Yanlin; Zhao, Zanmei; Guan, Li; Mao, Lijun; Li, Shuqiang; Guan, Xiaoxu; Chen, Ming; Guo, Lixia; Ding, Lihua; Cong, Cuicui; Wen, Tao; Zhao, Jinyuan

    2014-01-01

    Acute lung injury (ALI) is the leading cause of death in intensive care units. Extracellular histones have recently been recognized to be pivotal inflammatory mediators. Heparin and its derivatives can bind histones through electrostatic interaction. The purpose of this study was to investigate 1) the role of extracellular histones in the pathogenesis of ALI caused by acid aspiration and 2) whether N-acetyl-heparin (NAH) provides more protection than heparin against histones at the high dose. ALI was induced in mice via intratracheal instillation of hydrochloric acid (HCl). Lethality rate, blood gas, myeloperoxidase (MPO) activity, lung edema and pathological changes were used to evaluate the degree of ALI. Heparin/NAH was administered intraperitoneally, twice a day, for 3 days or until death. Acid aspiration caused an obvious increase in extracellular histones. A significant correlation existed between the concentration of HCl aspirated and the circulating histones. Heparin/NAH (10 mg/kg) improved the lethality rate, blood gas, MPO activity, lung edema and pathological score. At a dose of 20 mg/kg, NAH still provided protection, however heparin tended to aggravate the injury due to hemorrhagic complications. The specific interaction between heparin and histones was verified by the binding assay. In summary, high levels of extracellular histones can be pathogenic in ALI caused by acid aspiration. By neutralizing extracellular histones, heparin/NAH can offer similar protection at the moderate doses. At the high dose, NAH provides better protection than heparin.

  13. African Horse Sickness Caused by Genome Reassortment and Reversion to Virulence of Live, Attenuated Vaccine Viruses, South Africa, 2004–2014

    PubMed Central

    Weyer, Camilla T.; Grewar, John D.; Burger, Phillippa; Rossouw, Esthea; Lourens, Carina; Joone, Christopher; le Grange, Misha; Coetzee, Peter; Venter, Estelle; Martin, Darren P.; MacLachlan, N. James

    2016-01-01

    African horse sickness (AHS) is a hemorrhagic viral fever of horses. It is the only equine disease for which the World Organization for Animal Health has introduced specific guidelines for member countries seeking official recognition of disease-free status. Since 1997, South Africa has maintained an AHS controlled area; however, sporadic outbreaks of AHS have occurred in this area. We compared the whole genome sequences of 39 AHS viruses (AHSVs) from field AHS cases to determine the source of 3 such outbreaks. Our analysis confirmed that individual outbreaks were caused by virulent revertants of AHSV type 1 live, attenuated vaccine (LAV) and reassortants with genome segments derived from AHSV types 1, 3, and 4 from a LAV used in South Africa. These findings show that despite effective protection of vaccinated horses, polyvalent LAV may, paradoxically, place susceptible horses at risk for AHS. PMID:27442883

  14. Eye closure causes widespread low-frequency power increase and focal gamma attenuation in the human electrocorticogram

    PubMed Central

    Geller, Aaron S.; Burke, John F.; Sperling, Michael R.; Sharan, Ashwini D.; Litt, Brian; Baltuch, Gordon H.; Lucas, Timothy H.; Kahana, Michael J.

    2014-01-01

    Objective: We sought to characterize the effects of eye closure on EEG power using electrocorticography (ECoG). Specifically, we sought to elucidate the anatomical areas demonstrating an eye closure effect, and at which frequencies these effects occur. Methods: ECoG was recorded from 32 patients undergoing invasive monitoring for seizure focus localization. Patients were instructed to close and open their eyes repeatedly. ECoG power was compared in the epochs following eye closure and opening, for various frequency bands and brain regions. Results: We found that at low frequencies, eye closure causes widespread power increases involving all lobes of the brain. This effect was significant not only in the α (8–12 Hz) band but in the δ (2–4 Hz), θ (4–8 Hz), and β (15–30) bands as well. At high frequencies, eye closure causes comparatively focal power decreases over occipital cortex and frontal Brodmann areas 8 and 9. Conclusions: Eye closure (1) affects a broad range of frequencies outside the α band and (2) involves a distributed network of neural activity in anatomical areas outside visual cortex. Significance: This study constitutes the first large-scale, systematic application of ECoG to study eye closure, which is shown to influence a broad range of frequencies and brain regions. PMID:24631141

  15. Micro-light-pipe array with an excitation attenuation filter for lensless digital enzyme-linked immunosorbent assay

    NASA Astrophysics Data System (ADS)

    Takehara, Hironari; Nagasaki, Mizuki; Sasagawa, Kiyotaka; Takehara, Hiroaki; Noda, Toshihiko; Tokuda, Takashi; Ohta, Jun

    2016-03-01

    Digital enzyme-linked immunosorbent assay (ELISA) is used for detecting various biomarkers with hypersensitivity. We have been developing compact systems by replacing the fluorescence microscope with a CMOS image sensor. Here, we propose a micro-light-pipe array structure made of metal filled with dye-doped resin, which can be used as a fabrication substrate of the micro-reaction-chamber array of digital ELISA. The possibility that this structure enhances the coupling efficiency for fluorescence was simulated using a simple model. To realize the structure, we fabricated a 30-µm-thick micropipe array by copper electroplating around a thick photoresist pattern. The typical diameter of each fabricated micropipe was 10 µm. The pipes were filled with yellow-dye-doped epoxy resin. The transmittance ratio of fluorescence and excitation light could be controlled by adjusting the doping concentration. We confirmed that an angled excitation light incidence suppressed the leakage of excitation light.

  16. Ellipsoid Segmentation Model for Analyzing Light-Attenuated 3D Confocal Image Stacks of Fluorescent Multi-Cellular Spheroids

    PubMed Central

    Barbier, Michaël; Jaensch, Steffen; Cornelissen, Frans; Vidic, Suzana; Gjerde, Kjersti; de Hoogt, Ronald; Graeser, Ralph; Gustin, Emmanuel; Chong, Yolanda T.

    2016-01-01

    In oncology, two-dimensional in-vitro culture models are the standard test beds for the discovery and development of cancer treatments, but in the last decades, evidence emerged that such models have low predictive value for clinical efficacy. Therefore they are increasingly complemented by more physiologically relevant 3D models, such as spheroid micro-tumor cultures. If suitable fluorescent labels are applied, confocal 3D image stacks can characterize the structure of such volumetric cultures and, for example, cell proliferation. However, several issues hamper accurate analysis. In particular, signal attenuation within the tissue of the spheroids prevents the acquisition of a complete image for spheroids over 100 micrometers in diameter. And quantitative analysis of large 3D image data sets is challenging, creating a need for methods which can be applied to large-scale experiments and account for impeding factors. We present a robust, computationally inexpensive 2.5D method for the segmentation of spheroid cultures and for counting proliferating cells within them. The spheroids are assumed to be approximately ellipsoid in shape. They are identified from information present in the Maximum Intensity Projection (MIP) and the corresponding height view, also known as Z-buffer. It alerts the user when potential bias-introducing factors cannot be compensated for and includes a compensation for signal attenuation. PMID:27303813

  17. Selective pharmacological blockade of the 5-HT7 receptor attenuates light and 8-OH-DPAT induced phase shifts of mouse circadian wheel running activity

    PubMed Central

    Shelton, Jonathan; Yun, Sujin; Losee Olson, Susan; Turek, Fred; Bonaventure, Pascal; Dvorak, Curt; Lovenberg, Timothy; Dugovic, Christine

    2015-01-01

    Recent reports have illustrated a reciprocal relationship between circadian rhythm disruption and mood disorders. The 5-HT7 receptor may provide a crucial link between the two sides of this equation since the receptor plays a critical role in sleep, depression, and circadian rhythm regulation. To further define the role of the 5-HT7 receptor as a potential pharmacotherapy to correct circadian rhythm disruptions, the current study utilized the selective 5-HT7 antagonist JNJ-18038683 (10 mg/kg) in three different circadian paradigms. While JNJ-18038683 was ineffective at phase shifting the onset of wheel running activity in mice when administered at different circadian time (CT) points across the circadian cycle, pretreatment with JNJ-18038683 blocked non-photic phase advance (CT6) induced by the 5-HT1A/7 receptor agonist 8-OH-DPAT (3 mg/kg). Since light induced phase shifts in mammals are partially mediated via the modulation of the serotonergic system, we determined if JNJ-18038683 altered phase shifts induced by a light pulse at times known to phase delay (CT15) or advance (CT22) wheel running activity in free running mice. Light exposure resulted in a robust shift in the onset of activity in vehicle treated animals at both times tested. Administration of JNJ-18038683 significantly attenuated the light induced phase delay and completely blocked the phase advance. The current study demonstrates that pharmacological blockade of the 5-HT7 receptor by JNJ-18038683 blunts both non-photic and photic phase shifts of circadian wheel running activity in mice. These findings highlight the importance of the 5-HT7 receptor in modulating circadian rhythms. Due to the opposite modulating effects of light resetting between diurnal and nocturnal species, pharmacotherapy targeting the 5-HT7 receptor in conjunction with bright light therapy may prove therapeutically beneficial by correcting the desynchronization of internal rhythms observed in depressed individuals. PMID:25642174

  18. Selective pharmacological blockade of the 5-HT7 receptor attenuates light and 8-OH-DPAT induced phase shifts of mouse circadian wheel running activity.

    PubMed

    Shelton, Jonathan; Yun, Sujin; Losee Olson, Susan; Turek, Fred; Bonaventure, Pascal; Dvorak, Curt; Lovenberg, Timothy; Dugovic, Christine

    2014-01-01

    Recent reports have illustrated a reciprocal relationship between circadian rhythm disruption and mood disorders. The 5-HT7 receptor may provide a crucial link between the two sides of this equation since the receptor plays a critical role in sleep, depression, and circadian rhythm regulation. To further define the role of the 5-HT7 receptor as a potential pharmacotherapy to correct circadian rhythm disruptions, the current study utilized the selective 5-HT7 antagonist JNJ-18038683 (10 mg/kg) in three different circadian paradigms. While JNJ-18038683 was ineffective at phase shifting the onset of wheel running activity in mice when administered at different circadian time (CT) points across the circadian cycle, pretreatment with JNJ-18038683 blocked non-photic phase advance (CT6) induced by the 5-HT1A/7 receptor agonist 8-OH-DPAT (3 mg/kg). Since light induced phase shifts in mammals are partially mediated via the modulation of the serotonergic system, we determined if JNJ-18038683 altered phase shifts induced by a light pulse at times known to phase delay (CT15) or advance (CT22) wheel running activity in free running mice. Light exposure resulted in a robust shift in the onset of activity in vehicle treated animals at both times tested. Administration of JNJ-18038683 significantly attenuated the light induced phase delay and completely blocked the phase advance. The current study demonstrates that pharmacological blockade of the 5-HT7 receptor by JNJ-18038683 blunts both non-photic and photic phase shifts of circadian wheel running activity in mice. These findings highlight the importance of the 5-HT7 receptor in modulating circadian rhythms. Due to the opposite modulating effects of light resetting between diurnal and nocturnal species, pharmacotherapy targeting the 5-HT7 receptor in conjunction with bright light therapy may prove therapeutically beneficial by correcting the desynchronization of internal rhythms observed in depressed individuals.

  19. Interferon Gamma potentiates the injury caused by MPP(+) on SH-SY5Y cells, which is attenuated by the nitric oxide synthases inhibition.

    PubMed

    Titze-de-Almeida, Simoneide S; Lustosa, Cátia Faria; Horst, Camila Hillesheim; Bel, Elaine Del; Titze-de-Almeida, Ricardo

    2014-12-01

    This study examined whether the cytokine interferon (IFN) gamma plays a role in the injury of SH-SY5Y cells caused by MPP(+) (1-methyl-4-phenylpyridinium). First of all, IFN-gamma sensitized cells to the neurotoxin MPP(+), as determined by MTT (3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide) assay. MPP(+)-injured cells showed higher reactive oxygen species (ROS) levels, which was reinforced by IFN-gamma. The injury triggered a marked expression of the neuronal NOS (nNOS) enzyme. L-NAME [N(ω)-nitro-L-arginine methyl ester, a non-specific NOS inhibitor] reestablished the cell viability after IFN-gamma challenging, and recovered cells from MPP(+) injury (95.0 vs. 84.7 %; P < 0.05). Seven-NI (7-nitroindazole, a nNOS inhibitor) protected cells against the injury by MPP(+) co-administered with IFN-gamma. Both inhibitors restrained the apoptosis of SH-SY5Y cells caused by MPP(+)/IFN-gamma. Regarding oxidative stress, L-NAME and 7-NI attenuated the increase in ROS levels caused by MPP(+) (45.3 or 48.4 vs. 87.9 %, P < 0.05). Indeed, L-NAME was more effective than 7-NI for reducing oxidative stress caused by MPP(+) under IFN-gamma exposition. The nNOS gene silencing by small-interfering RNAs recovered cells challenged by IFN-gamma (24 h), or MPP(+) (8 h). In conclusion, IFN-gamma sensitizes cells to MPP(+)-induced injury, also causing an increase in ROS levels. Pretreating cells with L-NAME or 7-NI reverts both the oxidative stress and apoptosis triggered by the neurotoxin MPP(+). Taking together, our data reinforce that IFN-gamma and NOS enzymes play a role in oxidative stress and dopaminergic cell death triggered by MPP(+).

  20. Absence of ACAT-1 attenuates atherosclerosis but causes dry eye and cutaneous xanthomatosis in mice with congenital hyperlipidemia.

    PubMed

    Yagyu, H; Kitamine, T; Osuga, J; Tozawa, R; Chen, Z; Kaji, Y; Oka, T; Perrey, S; Tamura, Y; Ohashi, K; Okazaki, H; Yahagi, N; Shionoiri, F; Iizuka, Y; Harada, K; Shimano, H; Yamashita, H; Gotoda, T; Yamada, N; Ishibashi, S

    2000-07-14

    Acyl-CoA:cholesterol acyltransferase (ACAT) catalyzes esterification of cellular cholesterol. To investigate the role of ACAT-1 in atherosclerosis, we have generated ACAT-1 null (ACAT-1-/-) mice. ACAT activities were present in the liver and intestine but were completely absent in adrenal, testes, ovaries, and peritoneal macrophages in our ACAT-1-/- mice. The ACAT-1-/- mice had decreased openings of the eyes because of atrophy of the meibomian glands, a modified form of sebaceous glands normally expressing high ACAT activities. This phenotype is similar to dry eye syndrome in humans. To determine the role of ACAT-1 in atherogenesis, we crossed the ACAT-1-/- mice with mice lacking apolipoprotein (apo) E or the low density lipoprotein receptor (LDLR), hyperlipidemic models susceptible to atherosclerosis. High fat feeding resulted in extensive cutaneous xanthomatosis with loss of hair in both ACAT-1-/-:apo E-/- and ACAT-1-/-:LDLR-/- mice. Free cholesterol content was significantly increased in their skin. Aortic fatty streak lesion size as well as cholesteryl ester content were moderately reduced in both double mutant mice compared with their respective controls. These results indicate that the local inhibition of ACAT activity in tissue macrophages is protective against cholesteryl ester accumulation but causes cutaneous xanthomatosis in mice that lack apo E or LDLR.

  1. Disruption of the novel gene fad104 causes rapid postnatal death and attenuation of cell proliferation, adhesion, spreading and migration

    SciTech Connect

    Nishizuka, Makoto; Kishimoto, Keishi; Kato, Ayumi; Ikawa, Masahito; Okabe, Masaru; Sato, Ryuichiro; Niida, Hiroyuki; Nakanishi, Makoto; Osada, Shigehiro; Imagawa, Masayoshi

    2009-03-10

    The molecular mechanisms at the beginning of adipogenesis remain unknown. Previously, we identified a novel gene, fad104 (factor for adipocyte differentiation 104), transiently expressed at the early stage of adipocyte differentiation. Since the knockdown of the expression of fad104 dramatically repressed adipogenesis, it is clear that fad104 plays important roles in adipocyte differentiation. However, the physiological roles of fad104 are still unknown. In this study, we generated fad104-deficient mice by gene targeting. Although the mice were born in the expected Mendelian ratios, all died within 1 day of birth, suggesting fad104 to be crucial for survival after birth. Furthermore, analyses of mouse embryonic fibroblasts (MEFs) prepared from fad104-deficient mice provided new insights into the functions of fad104. Disruption of fad104 inhibited adipocyte differentiation and cell proliferation. In addition, cell adhesion and wound healing assays using fad104-deficient MEFs revealed that loss of fad104 expression caused a reduction in stress fiber formation, and notably delayed cell adhesion, spreading and migration. These results indicate that fad104 is essential for the survival of newborns just after birth and important for cell proliferation, adhesion, spreading and migration.

  2. [Light pollution increases morbidity and mortality rate from different causes in male rats].

    PubMed

    Bukalev, A V; Vinogradova, I A; Zabezhinskiĭ, M A; Semenchenko, A V; Anisimov, V N

    2012-01-01

    The influence of different light regimes (constant light--LL; constant darkness--DD; standard light regime--LD, 12 hours light 12 hours darkness; natural lightening of the North-West of Russia--NL) on the dynamics of life's morbidity rate, spontaneous tumorigenesis and frequency of some kinds of non-tumor pathology revealed at the post-mortem examination of male rats was studied. It was found out that the maintenance of animals at LL and NL conditions led to the increase of the number of infectious diseases, substantially faster development of spontaneous tumors and the increase of non-tumor diseases in comparison with the animals kept at LD (standard light) regime. Light deprivation (DD) led to substantial reduction of development of new growth, of non-tumor and infectious diseases in comparison with the similar parameters in standard light regime.

  3. The multiple organ dysfunction syndrome caused by endotoxin in the rat: attenuation of liver dysfunction by inhibitors of nitric oxide synthase.

    PubMed Central

    Thiemermann, C.; Ruetten, H.; Wu, C. C.; Vane, J. R.

    1995-01-01

    1. We have investigated whether (i) endotoxaemia caused by E. coli lipopolysaccharide in the anaesthetized rat causes a multiple organ dysfunction syndrome (MODS; e.g. circulatory failure, renal failure, liver failure), and (ii) an enhanced formation of nitric oxide (NO) due to induction of inducible NO synthase (iNOS) contributes to the MODS. In addition, this study elucidates the beneficial and adverse effects of aminoethyl-isothiourea (AE-ITU), a relatively selective inhibitor of iNOS activity, and NG-methyl-L-arginine (L-NMMA), a non-selective inhibitor of NOS activity on the MODS caused by endotoxaemia. 2. In the anaesthetized rat, LPS caused a fall in mean arterial blood pressure (MAP) from 117 +/- 3 mmHg (time 0) to 97 +/- 4 mmHg at 2 h (P < 0.05, n = 15) and 84 +/- 4 mmHg at 6 h (P < 0.05, n = 15). The pressor effect of noradrenaline (NA, 1 micrograms kg-1, i.v.) was also significantly reduced at 1 to 6 h after LPS (vascular hyporeactivity). Treatment of LPS-rats with AE-ITU (1 mg kg-1, i.v. plus 1 mg kg-1 h-1 starting at 2 h after LPS) caused only a transient rise in MAP, but significantly attenuated the delayed vascular hyporeactivity seen in LPS-rats. Infusion of L-NMMA (3 mg kg-1, i.v. plus 3 mg kg-1 h-1) caused a rapid and sustained rise in MAP and attenuated the delayed vascular hyporeactivity to NA. Neither AE-ITU nor L-NMMA had any effect on either MAP or the pressor effect elicited by NA in rats infused with saline rather than LPS. 3. Endotoxaemia for 6 h was associated with a significant rise in the serum levels of aspartate or alanine aminotransferase (i.e. GOT or GPT), gamma-glutamyl-transferase (gamma GT), and bilirubin, and hence, liver dysfunction. Treatment of LPS-rats with AE-ITU significantly attenuated this liver dysfunction (rise in GOT, GPT, gamma GT and bilirubin) (P < 0.05, n = 10). In contrast, L-NMMA reduced the increase in the serum levels of gamma GT and bilirubin, but not in GOT and GPT (n = 5). Injection of LPS also caused a

  4. Activated vitamin D3 and pro-activated vitamin D3 attenuate induction of permanent changes caused by neonatal estrogen exposure in the mouse vagina.

    PubMed

    Matsuda, Manabu; Kurosaki, Keiko; Okamura, Naomichi

    2014-01-01

    Exposure of mice to a high dose of estrogens including diethylstilbestrol (DES) during the neonatal period modifies the developmental plan of the genital tract, which leads to various permanent changes in physiology, morphology and gene expression. These changes include development of an abnormal vaginal epithelium lined with hyperplastic mucinous cells accompanied by Tff1 gene expression in mice. Here, the influence of vitamin D on the direct effect of estrogen on the developing mouse vagina was examined. The mid-vagina of neonatal mice was cultured in a serum-free medium containing estradiol-17β (E2) and various concentrations of 1,25-dihydroxyvitamin D3 (1,25(OH)2D) ex vivo and then was transplanted under the renal capsule of ovariectomized host mice for 35 days. Exposure to E2 alone caused the vaginal tissue to develop estrogen-independent epithelial hyperplasia and to express TFF1 mRNA, while addition of a low nanomolar amount of 1,25(OH)2D added at the same time as E2 to the culture medium attenuated the effects of estrogen. Expression of vitamin D receptor was also evident in the neonatal mouse vagina. Interestingly, addition of 25-hydroxyvitamin D3, a pro-activated form of vitamin D, at the micromolar level was found to be potent in disrupting the developmental effects of E2, while cholecalciferol was not at least at the dose examined. Correspondingly, expression of Cyp27B1, a kidney-specific 25-hydroxyvitamin D hydroxylase, was evident in the neonatal mouse vagina when examined by RT-PCR. In addition, simultaneous administration of 1,25(OH)2D successfully attenuated DES-induced ovary-independent hyperplasia in the vagina in neonatal mice in vivo. Thus, manipulation of vitamin D influenced the harmful effects of estrogens on mouse vaginal development.

  5. [The mechanism of phenoptosis: I. Age-dependent decrease of the overall rate of protein synthesis is caused by the programmed attenuation of bio-energetics].

    PubMed

    Trubitsyn, A G

    2009-01-01

    The age-dependent degradation of all vital processes of an organism can be result of influences of destructive factors (the stochastic mechanism of aging), or effect of realizations of the genetic program (phenoptosis). The stochastic free-radical theory of aging dominating now contradicts the set of empirical data, and the semicentenial attempts to create the means to slow down aging did not give any practical results. It makes obvious that the stochastic mechanism of aging is incorrect. At the same time, the alternative mechanism of the programmed aging is not developed yet but preconditions for it development have already been created. It is shown that the genes controlling process of aging exist (contrary to the customary opinion) and the increase in the level of damaged macromolecules (basic postulate of the free-radical theory) can be explained by programmed attenuation of bio-energetics. As the bio-energetics is a driving force of all vital processes, decrease of its level is capable to cause degradation of all functions of an organism. However to transform this postulate into a basis of the theory of phenoptosis it is necessary to show, that attenuation of bio-energetics predetermines such fundamental processes accompanying aging as decrease of the overall rate of protein biosynthesis, restriction of cellular proliferations (Hayflick limit), loss of telomeres etc. This article is the first step in this direction: the natural mechanism of interaction of overall rate of protein synthesis with a level of cellular bio-energetics is shown. This is built-in into the translation machine and based on dependence of recirculation rate of eukaryotic initiation factor 2 (elF2) from ATP/ADP value that is created by mitochondrial bio-energetic machine.

  6. Spotlight on fish: light pollution affects circadian rhythms of European perch but does not cause stress.

    PubMed

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Preuer, Torsten; Kloas, Werner

    2015-04-01

    Flora and fauna evolved under natural day and night cycles. However, natural light is now enhanced by artificial light at night, particularly in urban areas. This alteration of natural light environments during the night is hypothesised to alter biological rhythms in fish, by effecting night-time production of the hormone melatonin. Artificial light at night is also expected to increase the stress level of fish, resulting in higher cortisol production. In laboratory experiments, European perch (Perca fluviatilis) were exposed to four different light intensities during the night, 0 lx (control), 1 lx (potential light level in urban waters), 10 lx (typical street lighting at night) and 100 lx. Melatonin and cortisol concentrations were measured from water samples every 3h during a 24 hour period. This study revealed that the nocturnal increase in melatonin production was inhibited even at the lowest light level of 1 lx. However, cortisol levels did not differ between control and treatment illumination levels. We conclude that artificial light at night at very low intensities may disturb biological rhythms in fish since nocturnal light levels around 1 lx are already found in urban waters. However, enhanced stress induction could not be demonstrated.

  7. Overexpression of PCNA Attenuates Oxidative Stress-Caused Delay of Gap-Filling during Repair of UV-Induced DNA Damage

    PubMed Central

    Wang, Yi-Hsiang

    2017-01-01

    UVC irradiation-caused DNA lesions are repaired in mammalian cells solely by nucleotide excision repair (NER), which consists of sequential events including initial damage recognition, dual incision of damage site, gap-filling, and ligation. We have previously shown that gap-filling during the repair of UV-induced DNA lesions may be delayed by a subsequent treatment of oxidants or prooxidants such as hydrogen peroxide, flavonoids, and colcemid. We considered the delay as a result of competition for limiting protein/enzyme factor(s) during repair synthesis between NER and base excision repair (BER) induced by the oxidative chemicals. In this report, using colcemid as oxidative stress inducer, we showed that colcemid-caused delay of gap-filling during the repair of UV-induced DNA lesions was attenuated by overexpression of PCNA but not ligase-I. PCNA knockdown, as expected, delayed the gap-filling of NER but also impaired the repair of oxidative DNA damage. Fen-1 knockdown, however, did not affect the repair of oxidative DNA damage, suggesting repair of oxidative DNA damage is not of long patch BER. Furthermore, overexpression of XRCC1 delayed the gap-filling, and presumably increase of XRCC1 pulls PCNA away from gap-filling of NER for BER, consistent with our hypothesis that delay of gap-filling of NER attributes the competition between NER and BER. PMID:28116145

  8. Relationship between chlorophyll a concentration, light attenuation and diving depth of the Southern elephant seal Mirounga leonina.

    PubMed

    Jaud, Thomas; Dragon, Anne-Cécile; Garcia, Jade Vacquie; Guinet, Christophe

    2012-01-01

    Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K(0.75)) was used as an indicator of phytoplankton concentration. This measurement, easy to obtain and requiring low electric power, allows for assessing of the fine scale horizontal structuring of phytoplankton. As part of this study, Southern elephant seals (SES) were simultaneously equipped with a fluorometer and a light logger. Along the SES tracks, variations in K(0.75) were strongly correlated with chlorophyll, a concentration measured by the fluorometer within the euphotic layer. With regards to SES foraging behaviour, bottom depth of the seal's dive was highly dependent on light intensity at 150 m, indicating that the vertical distribution of SES's prey such as myctophids is tightly related to light level. Therefore, change in phytoplankton concentration may not only have a direct effect on SES's prey abundance but may also determine their vertical accessibility with likely consequences on SES foraging efficiency.

  9. Relationship between Chlorophyll a Concentration, Light Attenuation and Diving Depth of the Southern Elephant Seal Mirounga leonina

    PubMed Central

    Jaud, Thomas; Dragon, Anne-Cécile; Garcia, Jade Vacquie; Guinet, Christophe

    2012-01-01

    Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K0.75) was used as an indicator of phytoplankton concentration. This measurement, easy to obtain and requiring low electric power, allows for assessing of the fine scale horizontal structuring of phytoplankton. As part of this study, Southern elephant seals (SES) were simultaneously equipped with a fluorometer and a light logger. Along the SES tracks, variations in K0.75 were strongly correlated with chlorophyll, a concentration measured by the fluorometer within the euphotic layer. With regards to SES foraging behaviour, bottom depth of the seal’s dive was highly dependent on light intensity at 150 m, indicating that the vertical distribution of SES’s prey such as myctophids is tightly related to light level. Therefore, change in phytoplankton concentration may not only have a direct effect on SES’s prey abundance but may also determine their vertical accessibility with likely consequences on SES foraging efficiency. PMID:23082166

  10. Light-trap design using multiple reflections and solid-angle attenuation - Application to a spaceborne electron spectrometer

    NASA Technical Reports Server (NTRS)

    Herrero, Federico A.

    1992-01-01

    The design and performance of a new light trap for a spaceborne electron spectrometer are described. The light trap has a measured photon-rejection ratio of 2 x 10 exp -11, allowing only one in 5 x 10 exp 10 incident photons to reach the sensitive area of the instrument. This rejection is more than sufficient because the ambient UV in earth orbit requires a rejection no better than 10 exp -8 to maintain the photon interference to less than 10 count/s. The light trap uses triple reflections to keep most of the light passing through the entrance slit away from the sensitive area of the spectrometer. It is shown that the average reflectance of all the internal surfaces must be less than 0.006, which is consistent with the data on the black coating applied to all surfaces. The analysis makes it possible to compare the photon contributions of each of the internal reflecting areas and to estimate the effective scattering width of the metallic electrode edge.

  11. Pharmacological inhibition of PTEN attenuates cognitive deficits caused by neonatal repeated exposures to isoflurane via inhibition of NR2B-mediated tau phosphorylation in rats.

    PubMed

    Tan, Lei; Chen, Xin; Wang, Wei; Zhang, Jianfang; Li, Shiyong; Zhao, Yilin; Wang, Jintao; Luo, Ailin

    2017-03-01

    Evidence has shown that children exposed to repeated anesthesia in early childhood display long-term cognitive disabilities. However, the underlying mechanisms remain largely unclear. Our previous study has indicated the involvement of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in isoflurane-induced decrease of self-renewal capacity in hippocampal neural precursor cells. Additionally, it is demonstrated by others that PTEN inhibition could protect against cognitive impairment via reduction of tau phosphorylation in the alzheimer's disease model. Therefore, in the present in vivo study, we aimed to examine the effects of PTEN inhibition on the cognitive dysfunction and tau hyperphosphorylation caused by neonatal repeated exposures to isoflurane. Our results showed that the neonatal repeated exposures to isoflurane resulted in the activation of PTEN in the hippocampus. The treatment of PTEN inhibitor BPV (pic) restored PSD-95 synthesis, and attenuated tau phosphorylation as well as the cognitive dysfunction caused by the repeated isoflurane exposures. In addition, BPV (pic) treatment reversed the activation of NR2B-containing NMDARs induced by repeated isoflurane exposures, while in turn, the antagonism of NR2B subunit with ifenprodil alleviated tau phosphorylation, indicating a possible role of NR2B as the downstream of PTEN in mediating tau phosphorylation in the neonatal rats repeatedly exposed to isoflurane. In conclusion, our results reveal a novel role of PTEN in mediating tau phosphorylation and cognitive deficits caused by neonatal repeated exposures to isoflurane, implying that targeting on PTEN may be a potential therapeutic approach for the anesthetic-related cognitive decline in the developing brain.

  12. Contact binaries: II. The importance of deformation caused by rotation and tides to the light curve of a contact binary

    NASA Astrophysics Data System (ADS)

    Luo, ChangQing; Huang, RunQian

    2012-05-01

    The theoretical light curves of contact binaries are calculated with and without putting in the contact binary evolution model. Firstly, we do not use the contact binary evolution model. A comparison of the light curve is performed with and without the deformation caused by rotation and tides. It shows that the light curve presents many differences, especially on the bottom and top. Secondly, we adopt the contact binary model [Huang R Q, et al. Chin J Astron Astrophys, 2007, 7: 235-244; Song H F, et al. Chin J Astron Astrophys, 2007, 7: 539-550] and compute the theoretical light curve with and without rotational and tidal effects by studying three binary systems (with low-, intermediate- and high-mass components). The bottom and top of the theoretical light curves are discussed and compared to observations. The results show that taking into account the rotational effect has a better agreement with observations than without it. Therefore, the deformation of the light curve of contact binaries caused by rotation and tides is very important. Meanwhile, the rotational and tidal effect can advance the start of the semi-detached, contact phase and the time of mass-reversal.

  13. Artificial Lighting as a Vector Attractant and Cause of Disease Diffusion

    PubMed Central

    Barghini, Alessandro; de Medeiros, Bruno A. S.

    2010-01-01

    Background Traditionally, epidemiologists have considered electrification to be a positive factor. In fact, electrification and plumbing are typical initiatives that represent the integration of an isolated population into modern society, ensuring the control of pathogens and promoting public health. Nonetheless, electrification is always accompanied by night lighting that attracts insect vectors and changes people’s behavior. Although this may lead to new modes of infection and increased transmission of insect-borne diseases, epidemiologists rarely consider the role of night lighting in their surveys. Objective We reviewed the epidemiological evidence concerning the role of lighting in the spread of vector-borne diseases to encourage other researchers to consider it in future studies. Discussion We present three infectious vector-borne diseases—Chagas, leishmaniasis, and malaria—and discuss evidence that suggests that the use of artificial lighting results in behavioral changes among human populations and changes in the prevalence of vector species and in the modes of transmission. Conclusion Despite a surprising lack of studies, existing evidence supports our hypothesis that artificial lighting leads to a higher risk of infection from vector-borne diseases. We believe that this is related not only to the simple attraction of traditional vectors to light sources but also to changes in the behavior of both humans and insects that result in new modes of disease transmission. Considering the ongoing expansion of night lighting in developing countries, additional research on this subject is urgently needed. PMID:20675268

  14. Photomediated Reactive Oxygen Species-Generable Nanoparticles for Triggered Release and Endo/Lysosomal Escape of Drug upon Attenuated Single Light Irradiation.

    PubMed

    Seo, Eun Ha; Lee, Chung-Sung; Na, Kun

    2015-12-30

    Nanoparticles with "smart" stimuli-responsive materials and multiple therapeutic strategies in a single delivery platform have emerged for highly efficient cancer therapy. Here, photomediated reactive oxygen species (ROS)-generable nanoparticles are designed that can trigger drug release and endo/lysosomal escape upon attenuated single light irradiation, simultaneously, for synergistic chemo-photodynamic ablation. In this study, the self-ROS-generable nanoparticles (SRNs) are prepared from the polymer based on polysaccharide, chlorin e6 as ROS generator and lipoic acid as ROS scavenger covalently conjugated pullulan with anticancer drug (doxorubicin, DOX) through self-assembly, and can disassemble via the ROS-mediated reduction of lipoyl group in response to low level exogenous single light switch. After cellular internalization in hepatic cancer through asialoglycoprotein receptor (ASGPR, as pullulan receptor)-mediated endocytosis, once irradiated, SRNs are able to produce ROS that can simultaneously induce drug release triggering and endo/lysosomal escape of DOX into cytoplasm as well as directly photodynamic therapy for highly efficient chemo-photodynamic cancer therapy. This promising delivery system, which has huge potential in biomedical applications, may be optimal for smart delivery platform.

  15. Enhanced surface recombination in a-Si:H solar cells caused by light stress

    NASA Astrophysics Data System (ADS)

    Kusian, W.; Pfleiderer, H.

    1991-08-01

    The change of the spectral photocurrent characteristics of amorphous silicon pin solar cells with light induced degradation is compared with the effect of slightly doping the ``i-layer''. Both treatments yield similar results. Light stress lets the primary photocurrent, measured with blue light, decrease and the secondary photocurrent, measured with red light, increased. The similar change occurs when a slight n-doping of the ``i-layer'' is replaced by a slight p-doping. A simple interpretation in terms of unfirom fields and preponderant surface recombination is possible and will be outlined. We additionally resort to numerical similations. Degradation is to be simulated by the introduction of stronger recombination. The crombination rate will be distributed in space. We indeed find that enhanced surface recombination plays the key role in guiding the simulation towards our experiment.

  16. The influence of light attenuation on the biogeomorphology of a marine karst cave: A case study of Puerto Princesa Underground River, Palawan, the Philippines

    NASA Astrophysics Data System (ADS)

    Coombes, Martin A.; La Marca, Emanuela C.; Naylor, Larissa A.; Piccini, Leonardo; De Waele, Jo; Sauro, Francesco

    2015-01-01

    Karst caves are unique biogeomorphological systems. Cave walls offer habitat for microorganisms which in-turn have a geomorphological role via their involvement in rock weathering, erosion and mineralisation. The attenuation of light with distance into caves is known to affect ecology, but the implications of this for biogeomorphological processes and forms have seldom been examined. Here we describe a semi-quantitative microscopy study comparing the extent, structure, and thickness of biocover and depth of endolithic penetration for samples of rock from the Puerto Princesa Underground River system in Palawan, the Philippines, which is a natural UNESCO World Heritage Site. Organic growth at the entrance of the cave was abundant (100% occurrence) and complex, dominated by phototrophic organisms (green microalgae, diatoms, cyanobacteria, mosses and lichens). Thickness of this layer was 0.28 ± 0.18 mm with active endolith penetration into the limestone (mean depth = 0.13 ± 0.03 mm). In contrast, phototrophs were rare 50 m into the cave and biofilm cover was significantly thinner (0.01 ± 0.01 mm, p < 0.000) and spatially patchy (33% occurrence). Endolithic penetration here was also shallower (< 0.01 mm, p < 0.000) and non-uniform. Biofilm was found 250 m into the cave, but with a complete absence of phototrophs and no evidence of endolithic bioerosion. We attribute these findings to light-induced stress gradients, showing that the influence of light on phototroph abundance has knock-on consequences for the development of limestone morphological features. In marine caves this includes notches, which were most well-developed at the sheltered cave entrance of our study site, and for which variability in formation rates between locations is currently poorly understood.

  17. Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    NASA Astrophysics Data System (ADS)

    Takanabe, Akifumi; Tanaka, Masahito; Taniguchi, Atsuo; Yamanaka, Hisashi; Asahi, Toru

    2014-07-01

    To improve our ability to identify single crystals causing arthritis, we have developed a practical measurement system of polarized light microscopy called advanced compensated polarized light microscopy (A-CPLM). The A-CPLM system is constructed by employing a conventional phase retardation plate, an optical fibre and a charge-coupled device spectrometer in a polarized light microscope. We applied the A-CPLM system to measure linear birefringence (LB) in the visible region, which is an optical anisotropic property, for tiny single crystals causing arthritis, i.e. monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD). The A-CPLM system performance was evaluated by comparing the obtained experimental data using the A-CPLM system with (i) literature data for a standard sample, MgF2, and (ii) experimental data obtained using an established optical method, high-accuracy universal polarimeter, for the MSUM. The A-CPLM system was found to be applicable for measuring the LB spectra of the single crystals of MSUM and CPPD, which cause arthritis, in the visible regions. We quantitatively reveal the large difference in LB between MSUM and CPPD crystals. These results demonstrate the usefulness of the A-CPLM system for distinguishing the crystals causing arthritis.

  18. Inhibition of Myosin light-chain kinase attenuates cerebral edema after traumatic brain injury in postnatal mice.

    PubMed

    Rossi, Janet L; Todd, Tracey; Bazan, Nicolas G; Belayev, Ludmila

    2013-10-01

    Traumatic brain injury (TBI) in children less than 8 years of age leads to decline in intelligence and executive functioning. Neurological outcomes after TBI correlate to development of cerebral edema, which affect survival rates after TBI. It has been shown that myosin light-chain kinase (MLCK) increases cerebral edema and that pretreatment with an MLCK inhibitor (ML-7) reduces cerebral edema. The aim of this study was to determine whether inhibition of MLCK after TBI in postnatal day 24 (PND-24) mice would prevent breakdown of the blood-brain barrier (BBB) and development of cerebral edema and improve neurological outcome. We used a closed head injury model of TBI. ML-7 or saline treatment was administered at 4 h and every 24 h until sacrifice or 5 days after TBI. Mice were sacrificed at 24 h, 48 h, and 72 h and 7 days after impact. Mice treated with ML-7 after TBI had decreased levels of MLCK-expressing cells (20.7±4.8 vs. 149.3±40.6), less albumin extravasation (28.3±11.2 vs. 116.2±60.7 mm(2)) into surrounding parenchymal tissue, less Evans Blue extravasation (339±314 vs. 4017±560 ng/g), and showed a significant difference in wet/dry weight ratio (1.9±0.07 vs. 2.2±0.05 g), compared to saline-treated groups. Treatment with ML-7 also resulted in preserved neurological function measured by the wire hang test (57 vs. 21 sec) and two-object novel recognition test (old vs. new, 10.5 touches). We concluded that inhibition of MLCK reduces cerebral edema and preserves neurological function in PND-24 mice.

  19. An attenuated Lassa vaccine in SIV-infected rhesus macaques does not persist or cause arenavirus disease but does elicit Lassa virus-specific immunity

    PubMed Central

    2013-01-01

    Background Lassa hemorrhagic fever (LHF) is a rodent-borne viral disease that can be fatal for human beings. In this study, an attenuated Lassa vaccine candidate, ML29, was tested in SIV-infected rhesus macaques for its ability to elicit immune responses without instigating signs pathognomonic for arenavirus disease. ML29 is a reassortant between Lassa and Mopeia viruses that causes a transient infection in non-human primates and confers sterilizing protection from lethal Lassa viral challenge. However, since the LHF endemic area of West Africa also has high HIV seroprevalence, it is important to determine whether vaccination could be safe in the context of HIV infection. Results SIV-infected and uninfected rhesus macaques were vaccinated with the ML29 virus and monitored for specific humoral and cellular immune responses, as well as for classical and non-classical signs of arenavirus disease. Classical disease signs included viremia, rash, respiratory distress, malaise, high liver enzyme levels, and virus invasion of the central nervous system. Non-classical signs, derived from profiling the blood transcriptome of virulent and non-virulent arenavirus infections, included increased expression of interferon-stimulated genes (ISG) and decreased expression of COX2, IL-1β, coagulation intermediates and nuclear receptors needed for stress signaling. All vaccinated monkeys showed ML29-specific antibody responses and ML29-specific cell-mediated immunity. Conclusion SIV-infected and uninfected rhesus macaques responded similarly to ML29 vaccination, and none developed chronic arenavirus infection. Importantly, none of the macaques developed signs, classical or non-classical, of arenavirus disease. PMID:23402317

  20. Radiation Force Caused by Scattering, Absorption, and Emission of Light by Nonspherical Particles

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael I.; Hansen, James E. (Technical Monitor)

    2001-01-01

    General formulas for computing the radiation force exerted on arbitrarily oriented and arbitrarily shaped nonspherical particles due to scattering, absorption, and emission of electromagnetic radiation are derived. For randomly oriented particles with a plane of symmetry, the formula for the average radiation force caused by the particle response to external illumination reduces to the standard Debye formula derived from the Lorenz-Mie theory, whereas the average radiation force caused by emission vanishes.

  1. Ti-O-O coordination bond caused visible light photocatalytic property of layered titanium oxide

    PubMed Central

    Kong, Xingang; Zeng, Chaobin; Wang, Xing; Huang, Jianfeng; Li, Cuiyan; Fei, Jie; Li, Jiayin; Feng, Qi

    2016-01-01

    The layered titanium oxide is a useful and unique precursor for the facile and rapid preparation of the peroxide layered titanium oxide H1.07Ti1.73O4·nH2O (HTO) crystal with enhanced visible light photoactivity. The H2O2 molecules as peroxide chemicals rapidly enter into the interlayers of HTO crystal, and coordinate with Ti within TiO6 octahedron to form a mass of Ti-O-O coordination bond in the interlayers. The introduction of these Ti-O-O coordination bonds result in lowering the band gap of HTO, and promoting the separation efficiency of the photo induced electron–hole pairs. Meanwhile, the photocatalytic investigation indicates that such peroxide HTO crystal has the enhanced photocatalytic performance for RhB degradation and water splitting to generate oxygen under visible light irradiating. PMID:27350285

  2. Light-scattering changes caused by RBC aggregation: physical basis for new approach to noninvasive blood count

    NASA Astrophysics Data System (ADS)

    Shvartsman, Leonid D.; Fine, Ilya

    2001-06-01

    We develop theoretical models of light transmission through whole blood considering RBC aggregation. RBC aggregates are considered to be the main centers of scattering in red/near- infrared spectral region. In pulsatile blood flow the periodic changes of aggregate geometry cause oscillations of light scattering. Thus scattering-assisted mechanism has to be taken into account in pulse oximeter calibration. In case of over-systolic vessel occlusion the size of aggregates grows, and the light transmission rises. Light diffraction on a single scatterer makes the transmission growth non- monotonic for certain spectral range. For the most typical set of aggregate parameters this range corresponds to wavelengths below 760 nm, and this prediction fits well both in vivo and in vitro experimental results. This spectral range depends on the refraction index mismatch and the geometry of aggregates. Both of them may be affected by the chemistry of blood. For instance, changes of glucose and hemoglobin have different effect on light transmission time response. Consequently, their content may be determined from time evolution of optical transmission.

  3. Silicon phthalocyanine Pc 4 and red light causes apoptosis in HIV-infected cells.

    PubMed

    Ben-Hur, E; Oetjen, J; Horowitz, B

    1997-03-01

    The silicon phthalocyanine HOSiPcOSi(CH3)2(CH2)3 N(CH3)2 (Pc 4), is being studied as a photosensitizer for virus inactivation in red blood cell concentrates (RBCC). The RBCC spiked with cell-free human immunodeficiency virus (HIV) or with HIV actively replicating in the T-lymphocytic cell line CEM can be successfully inactivated (> or = 6 log10) when exposed to 2 microM Pc 4 and 90 J/cm2 red light (600-800 nm). Inactivation of > or = 6 log10 inducible HIV in the latently infected promonocytic cell line U1 occurred at 22.5 J/cm2 (H. Margolis-Nunno et al., Transfusion 36, 743-750, 1996). In order to understand the reason for the increased susceptibility of U1 to photosensitized inactivation we looked for induction of apoptosis by photodynamic treatment (PDT). Agarose gel electrophoresis was used to observe the appearance of a characteristic 180-200 base pair DNA ladder, which can indicate apoptosis. Using this assay it is shown that Pc 4 treatment induced apoptosis in U1 cells in a light dose-dependent manner, starting 30 min after light exposure. Using the ApopTag Plus kit (which attaches a fluorescent label to the 3'-OH ends of the degraded DNA) and flow cytometry, the percentage of cells undergoing apoptosis was quantitated. At 10.5 J/cm2, 3 h after light exposure, about 92.5% of the cells were apoptotic. Under these conditions 99% of the cells eventually die. The CEM cells similarly treated underwent apoptosis at slower kinetics and required higher light doses. Other cell lines latently infected with HIV (ACH-2 and OM 10.1) were as sensitive as U1 to HIV inactivation by Pc 4-PDT (H. Margolis-Nunno et al., Transfusion 36, 743-750, 1996) and underwent apoptosis at a similar kinetic. These results suggest that the enhanced inactivation of HIV in latently infected cells compared to CEM cells by Pc 4-PDT may be due, at least in part, to apoptosis in the former.

  4. Identification of the Mechanisms Causing Reversion to Virulence in an Attenuated SARS-CoV for the Design of a Genetically Stable Vaccine.

    PubMed

    Jimenez-Guardeño, Jose M; Regla-Nava, Jose A; Nieto-Torres, Jose L; DeDiego, Marta L; Castaño-Rodriguez, Carlos; Fernandez-Delgado, Raul; Perlman, Stanley; Enjuanes, Luis

    2015-10-01

    A SARS-CoV lacking the full-length E gene (SARS-CoV-∆E) was attenuated and an effective vaccine. Here, we show that this mutant virus regained fitness after serial passages in cell culture or in vivo, resulting in the partial duplication of the membrane gene or in the insertion of a new sequence in gene 8a, respectively. The chimeric proteins generated in cell culture increased virus fitness in vitro but remained attenuated in mice. In contrast, during SARS-CoV-∆E passage in mice, the virus incorporated a mutated variant of 8a protein, resulting in reversion to a virulent phenotype. When the full-length E protein was deleted or its PDZ-binding motif (PBM) was mutated, the revertant viruses either incorporated a novel chimeric protein with a PBM or restored the sequence of the PBM on the E protein, respectively. Similarly, after passage in mice, SARS-CoV-∆E protein 8a mutated, to now encode a PBM, and also regained virulence. These data indicated that the virus requires a PBM on a transmembrane protein to compensate for removal of this motif from the E protein. To increase the genetic stability of the vaccine candidate, we introduced small attenuating deletions in E gene that did not affect the endogenous PBM, preventing the incorporation of novel chimeric proteins in the virus genome. In addition, to increase vaccine biosafety, we introduced additional attenuating mutations into the nsp1 protein. Deletions in the carboxy-terminal region of nsp1 protein led to higher host interferon responses and virus attenuation. Recombinant viruses including attenuating mutations in E and nsp1 genes maintained their attenuation after passage in vitro and in vivo. Further, these viruses fully protected mice against challenge with the lethal parental virus, and are therefore safe and stable vaccine candidates for protection against SARS-CoV.

  5. Causes of variability in light absorption by particles in snow at sites in Idaho and Utah

    NASA Astrophysics Data System (ADS)

    Doherty, Sarah J.; Hegg, Dean A.; Johnson, James E.; Quinn, Patricia K.; Schwarz, Joshua P.; Dang, Cheng; Warren, Stephen G.

    2016-05-01

    A characterization of black carbon (BC) and other light-absorbing particles in snow is presented for three mountain valley sites in Idaho in early 2014 and for one site near Vernal, Utah, in early 2013 and 2014. The focus of the study was on constraining the magnitude and drivers of variations in particulate absorbers in midlatitude U.S. seasonal snow. Mass mixing ratios of BC in newly fallen snow were similar at all three Idaho sites, with a median of 4.7 ± 4.2 ng BC per gram of snow. The median total light-absorbing particulate mixing ratios in new snow, expressed as an equivalent mixing ratio of BC, was 18 ± 23 ng g-1. At the Utah site, which is near sources of both fossil fuel and dust, the mixing ratios of BC varied from 7 to 45 ng g-1 across seven new snowfall samples, and the BC-equivalent mixing ratios varied from 9 to 1500 ng g-1. At all sites, dry deposition and in-snow processes increase the mixing ratio of BC by up to an order of magnitude and increase the mixing ratio of all light-absorbing particulates by up to 2 orders of magnitude, highlighting the importance of capturing these processes for accurately representing snow albedo in climate models. Spatial variability at a range of scales is found to be considerably smaller than the temporal variations at a given site, with implications for the representativeness of field samples used in observation/model comparisons.

  6. Adjustable Optical-Fiber Attenuator

    NASA Technical Reports Server (NTRS)

    Buzzetti, Mike F.

    1994-01-01

    Adjustable fiber-optic attenuator utilizes bending loss to reduce strength of light transmitted along it. Attenuator functions without introducing measurable back-reflection or insertion loss. Relatively insensitive to vibration and changes in temperature. Potential applications include cable television, telephone networks, other signal-distribution networks, and laboratory instrumentation.

  7. Light

    NASA Astrophysics Data System (ADS)

    Vernon, C. G.

    2016-09-01

    Preface; 1. Historical; 2. Waves and wave-motion; 3. The behaviour of ripples; 4. The behaviour of light; 5. Refraction through glass blocks and prisms; 6. The imprinting of curvatures; 7. Simple mathematical treatment; 8. More advanced mathematical treatment; 9. The velocity of light; 10. The spectrum and colour; 11. Geometrical optics; 12. The eye and optical instruments; 13. Sources of light; 14. Interference, diffraction and polarisation; 15. Suggestions for class experiments; Index.

  8. Angular absorption of light used for evaluation of structural damage to porcine meat caused by aging, drying and freezing.

    PubMed

    Kaspar, Pavel; Prokopyeva, Elena; Tománek, Pavel; Grmela, Lubomír

    2017-04-01

    Meat as a rich source of protein is sought after by people from all over the world. It is also very susceptible to decay because of many internal and external processes affecting it. In this work an easy and quick method of detection of structural damage caused by decay or mishandling the meat is attempted by the method of angular absorption of light. The difference between structural changes due to aging, drying and freezing is explored and the resulting changes in light absorption in meat samples are presented. This work demonstrates that the measurement of optical angular dependency of absorption in relation to the muscle fibers in muscle tissue has the potential of detecting structural damage to the sample for meat quality control purposes.

  9. Synonymous deoptimization of the foot-and-mouth disease virus P1 coding region causes attenuation in vivo while inducing a strong neutralizing antibody response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Codon bias deoptimization has been previously used to successfully attenuate human pathogens including polio, respiratory syncytial and influenza viruses. We have applied a similar technology to deoptimize the capsid coding region (P1 region) of the cDNA infectious clone of foot-and-mouth disease vi...

  10. On modifications of Reichenbachʼs principle of common cause in light of Bellʼs theorem

    NASA Astrophysics Data System (ADS)

    Cavalcanti, Eric G.; Lal, Raymond

    2014-10-01

    Bell's 1964 theorem causes a severe problem for the notion that correlations require explanation, encapsulated in Reichenbach's principle of common cause. Despite being a hallmark of scientific thought, dropping the principle has been widely regarded as much less bitter medicine than the perceived alternative—dropping relativistic causality. Recently, however, some authors have proposed that modified forms of Reichenbach's principle could be maintained even with relativistic causality. Here we break down Reichenbach's principle into two independent assumptions—the principle of common cause proper and factorization of probabilities. We show how Bell's theorem can be derived from these two assumptions plus relativistic causality and the law of total probability for actual events, and we review proposals to drop each of these assumptions in light of the theorem. In particular, we show that the non-commutative common causes of Hofer-Szabó and Vecsernyés fail to have an analogue of the notion that the common causes can explain the observed correlations. Moreover, we show that their definition can be satisfied trivially by any quantum product state for any quantum correlations. We also discuss how the conditional states approach of Leifer and Spekkens fares in this regard. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘50 years of Bell’s theorem’.

  11. Peripheral mGluR5 antagonist attenuated craniofacial muscle pain and inflammation but not mGluR1 antagonist in lightly anesthetized rats.

    PubMed

    Lee, Ho Jeong; Choi, Hyo Soon; Ju, Jin Sook; Bae, Yong Chul; Kim, Sung Kyo; Yoon, Young Wook; Ahn, Dong Kuk

    2006-10-16

    The present study investigated the role of peripheral group I metabotropic glutamate receptors (mGluRs) in MO-induced nociceptive behaviour and inflammation in the masseter muscles of lightly anesthetized rats. Experiments were carried out on male Sprague-Dawley rats weighing 300-400 g. After initial anesthesia with sodium pentobarbital (40 mg/kg, i.p.), one femoral vein was cannulated and connected to an infusion pump for intravenous infusion of sodium pentobarbital. The rate of infusion was adjusted to provide a constant level of anesthesia. Mustard oil (MO, 30 microl) was injected into the mid-region of the left masseter muscle via a 30-gauge needle over 10s. After 30 microl injection of 5, 10, 15, or 20% MO into the masseter muscle, the total number of hindpaw shaking behaviour and extravasated Evans' blue dye concentration in the masseter muscle were significantly higher in the MO-treated group in a dose-dependent manner compared with the vehicle (mineral oil)-treated group. Intramuscular pretreatment with 3 or 5% lidocaine reduced MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration. Intramuscular pretreatment with 5 mM MCPG, non-selective group I/II mGluR antagonist, or MPEP, a selective group I mGluR5 antagonist, produced a significant attenuation of MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration in the masseter muscle while LY367385, a selective group I mGluR1 antagonist, did not affect MO-induced nociceptive behaviour and inflammation in the masseter muscle. These results indicate that peripheral mGluR5 plays important role in mediating MO-induced nociceptive behaviour and inflammation in the craniofacial muscle.

  12. Extragalactic background light from hierarchical galaxy formation. Gamma-ray attenuation up to the epoch of cosmic reionization and the first stars

    SciTech Connect

    Inoue, Yoshiyuki; Inoue, Susumu; Kobayashi, Masakazu A. R.; Makiya, Ryu; Niino, Yuu; Totani, Tomonori

    2013-04-26

    Here, we present a new model of the extragalactic background light (EBL) and corresponding γγ opacity for intergalactic gamma-ray absorption from z = 0 up to z = 10, based on a semi-analytical model of hierarchical galaxy formation that reproduces key observed properties of galaxies at various redshifts. Including the potential contribution from Population III stars and following the cosmic reionization history in a simplified way, the model is also broadly consistent with available data concerning reionization, particularly the Thomson scattering optical depth constraints from Wilkinson Microwave Anisotropy Probe (WMAP). In comparison with previous EBL studies up to z ~ 3-5, our predicted γγ opacity is in general agreement for observed gamma-ray energy below 400/(1 + z) GeV, whereas it is a factor of ~2 lower above this energy because of a correspondingly lower cosmic star formation rate, even though the observed ultraviolet (UV) luminosity is well reproduced by virtue of our improved treatment of dust obscuration and direct estimation of star formation rate. Moreover, the horizon energy at which the gamma-ray opacity is unity does not evolve strongly beyond z ~ 4 and approaches ~20 GeV. The contribution of Population III stars is a minor fraction of the EBL at z = 0, and is also difficult to distinguish through gamma-ray absorption in high-z objects, even at the highest levels allowed by the WMAP constraints. Nevertheless, the attenuation due to Population II stars should be observable in high-z gamma-ray sources by telescopes such as Fermi or the Cherenkov Telescope Array and provide a valuable probe of the evolving EBL in the rest-frame UV. Our detailed results of our model are publicly available in numerical form at http://www.slac.stanford.edu/~yinoue/Download.html.

  13. Deficiency in ubiquitin ligase TRIM2 causes accumulation of neurofilament light chain and neurodegeneration

    PubMed Central

    Balastik, Martin; Ferraguti, Francesco; Pires-da Silva, André; Lee, Tae Ho; Alvarez-Bolado, Gonzalo; Lu, Kun Ping; Gruss, Peter

    2008-01-01

    TRIM RING finger proteins have been shown to play an important role in cancerogenesis, in the pathogenesis of some human hereditary disorders, and in the defense against viral infection, but the function of the majority of TRIM proteins remains unknown. Here, we show that TRIM RING finger protein TRIM2, highly expressed in the nervous system, is an UbcH5a-dependent ubiquitin ligase. We further demonstrate that TRIM2 binds to neurofilament light subunit (NF-L) and regulates NF-L ubiquitination. Additionally, we show that mice deficient in TRIM2 have increased NF-L level in axons and NF-L-filled axonal swellings in cerebellum, retina, spinal cord, and cerebral cortex. The axonopathy is followed by progressive neurodegeneration accompanied by juvenile-onset tremor and ataxia. Our results demonstrate that TRIM2 is an ubiquitin ligase and point to a mechanism regulating NF-L metabolism through an ubiquitination pathway that, if deregulated, triggers neurodegeneration. PMID:18687884

  14. Discolouration of orthodontic adhesives caused by food dyes and ultraviolet light.

    PubMed

    Faltermeier, Andreas; Rosentritt, Martin; Reicheneder, Claudia; Behr, Michael

    2008-02-01

    Enamel discolouration after debonding of orthodontic attachments could occur because of irreversible penetration of resin tags into the enamel structure. Adhesives could discolour because of food dyes or ultraviolet irradiation. The aim of this study was to investigate the colour stability of adhesives during ultraviolet irradiation and exposure to food colourants. Four different adhesives were exposed in a Suntest CPS+ ageing device to a xenon lamp to simulate natural daylight (Transbond XT, Enlight, RelyX Unicem, and Meron Plus AC). Tomato ketchup, Coca Cola, and tea were chosen as the food colourants. After 72 hours of exposure, colour measurements were performed by means of a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system and colour changes (DeltaE*) were computed. Statistical differences were investigated using two-way analysis of variance (ANOVA) and Friedman test. Unsatisfactory colour stability after in vitro exposure to food colourants and ultraviolet light was observed for the conventional adhesive systems, Transbond XT and Enlight. RelyX Unicem showed the least colour change and the resin-reinforced glass-ionomer cement (GIC), Meron Plus AC, the greatest colour change. The investigated adhesives seem to be susceptible to both internal and external discolouration. These in vitro findings indicate that the tested conventional adhesive systems reveal unsatisfactory colour stability which should be improved to avoid enamel discolouration.

  15. A mutation in the atrial-specific myosin light chain gene (MYL4) causes familial atrial fibrillation.

    PubMed

    Orr, Nathan; Arnaout, Rima; Gula, Lorne J; Spears, Danna A; Leong-Sit, Peter; Li, Qiuju; Tarhuni, Wadea; Reischauer, Sven; Chauhan, Vijay S; Borkovich, Matthew; Uppal, Shaheen; Adler, Arnon; Coughlin, Shaun R; Stainier, Didier Y R; Gollob, Michael H

    2016-04-12

    Atrial fibrillation (AF), the most common arrhythmia, is a growing epidemic with substantial morbidity and economic burden. Mechanisms underlying vulnerability to AF remain poorly understood, which contributes to the current lack of highly effective therapies. Recognizing mechanistic subtypes of AF may guide an individualized approach to patient management. Here, we describe a family with a previously unreported syndrome characterized by early-onset AF (age <35 years), conduction disease and signs of a primary atrial myopathy. Phenotypic penetrance was complete in all mutation carriers, although complete disease expressivity appears to be age-dependent. We show that this syndrome is caused by a novel, heterozygous p.Glu11Lys mutation in the atrial-specific myosin light chain gene MYL4. In zebrafish, mutant MYL4 leads to disruption of sarcomeric structure, atrial enlargement and electrical abnormalities associated with human AF. These findings describe the cause of a rare subtype of AF due to a primary, atrial-specific sarcomeric defect.

  16. Correction of quantification errors in pelvic and spinal lesions caused by ignoring higher photon attenuation of bone in [{sup 18}F]NaF PET/MR

    SciTech Connect

    Schramm, Georg Maus, Jens; Hofheinz, Frank; Petr, Jan; Lougovski, Alexandr; Beuthien-Baumann, Bettina; Oehme, Liane; Platzek, Ivan; Hoff, Jörg van den

    2015-11-15

    Purpose: MR-based attenuation correction (MRAC) in routine clinical whole-body positron emission tomography and magnetic resonance imaging (PET/MRI) is based on tissue type segmentation. Due to lack of MR signal in cortical bone and the varying signal of spongeous bone, standard whole-body segmentation-based MRAC ignores the higher attenuation of bone compared to the one of soft tissue (MRAC{sub nobone}). The authors aim to quantify and reduce the bias introduced by MRAC{sub nobone} in the standard uptake value (SUV) of spinal and pelvic lesions in 20 PET/MRI examinations with [{sup 18}F]NaF. Methods: The authors reconstructed 20 PET/MR [{sup 18}F]NaF patient data sets acquired with a Philips Ingenuity TF PET/MRI. The PET raw data were reconstructed with two different attenuation images. First, the authors used the vendor-provided MRAC algorithm that ignores the higher attenuation of bone to reconstruct PET{sub nobone}. Second, the authors used a threshold-based algorithm developed in their group to automatically segment bone structures in the [{sup 18}F]NaF PET images. Subsequently, an attenuation coefficient of 0.11 cm{sup −1} was assigned to the segmented bone regions in the MRI-based attenuation image (MRAC{sub bone}) which was used to reconstruct PET{sub bone}. The automatic bone segmentation algorithm was validated in six PET/CT [{sup 18}F]NaF examinations. Relative SUV{sub mean} and SUV{sub max} differences between PET{sub bone} and PET{sub nobone} of 8 pelvic and 41 spinal lesions, and of other regions such as lung, liver, and bladder, were calculated. By varying the assigned bone attenuation coefficient from 0.11 to 0.13 cm{sup −1}, the authors investigated its influence on the reconstructed SUVs of the lesions. Results: The comparison of [{sup 18}F]NaF-based and CT-based bone segmentation in the six PET/CT patients showed a Dice similarity of 0.7 with a true positive rate of 0.72 and a false discovery rate of 0.33. The [{sup 18}F]NaF-based bone

  17. Shining Light on the Cause of Alzheimer's Disease (411th Brookhaven Lecture)

    SciTech Connect

    Miller, Lisa

    2006-01-18

    Alzheimer’s disease is a progressive brain disorder that gradually destroys a person’s memory and ability to learn, reason, communicate and carry out daily activities. An estimated 4.5 million Americans have it, a number that is expected to triple over the next 50 years. Today, one in ten people aged 65 and half of people over 85 are affected. The cause of Alzheimer’s disease is thought to involve the formation of “plaques” — tiny aggregates of a naturally occurring, but misfolded or misshapen protein — in the brain. Recently, the formation of these plaques has been associated with the binding of metal ions such as iron, copper, and zinc. Yet the function of these metal ions and the misfolded proteins in the disease process is not well understood. Now, synchrotron infrared and x-ray microscopes are used to image the protein structure and metal content in the Alzheimer’s-affected brain tissue, providing a better understanding of how the disease occurs and potential ways of preventing it in the future.

  18. Ferrite attenuator modulation improves antenna performance

    NASA Technical Reports Server (NTRS)

    Hooks, J. C.; Larson, S. G.; Shorkley, F. H.; Williams, B. T.

    1970-01-01

    Ferrite attenuator inserted into appropriate waveguide reduces the gain of the antenna element which is causing interference. Modulating the ferrite attenuator to change the antenna gain at the receive frequency permits ground tracking until the antenna is no longer needed.

  19. Estimation of economic losses caused by disruption of lifeline service: An analysis of the Memphis Light, Gas and Water system

    SciTech Connect

    Chang, S.E.; Seligson, H.A.; Eguchi, R.T.

    1995-12-31

    The assessment of economic impact remains an important missing link in earthquake loss estimation procedures. This paper presents a general methodology for evaluating the economic losses caused by seismically-induced disruption of lifeline service in an urban area. The methodology consists of three steps: (1) development of a lifeline usage model on an industry basis; (2) estimation of the spatial distribution of economic activity throughout the urban area; and (3) assessment of direct losses through evaluation of the spatial coincidence of economic activity with lifeline service disruption. To demonstrate this methodology, a pilot analysis was conducted on the Memphis Light, Gas and Water electric power system for a Magnitude 7.5 earthquake in New Madrid seismic Zone. Using newly-available empirical data, business interruption in Shelby County, Tennessee, was estimated for major industries in the local economy. Extensions of the methodology are also discussed.

  20. A mutation in the atrial-specific myosin light chain gene (MYL4) causes familial atrial fibrillation

    PubMed Central

    Orr, Nathan; Arnaout, Rima; Gula, Lorne J.; Spears, Danna A.; Leong-Sit, Peter; Li, Qiuju; Tarhuni, Wadea; Reischauer, Sven; Chauhan, Vijay S.; Borkovich, Matthew; Uppal, Shaheen; Adler, Arnon; Coughlin, Shaun R.; Stainier, Didier Y. R.; Gollob, Michael H.

    2016-01-01

    Atrial fibrillation (AF), the most common arrhythmia, is a growing epidemic with substantial morbidity and economic burden. Mechanisms underlying vulnerability to AF remain poorly understood, which contributes to the current lack of highly effective therapies. Recognizing mechanistic subtypes of AF may guide an individualized approach to patient management. Here, we describe a family with a previously unreported syndrome characterized by early-onset AF (age <35 years), conduction disease and signs of a primary atrial myopathy. Phenotypic penetrance was complete in all mutation carriers, although complete disease expressivity appears to be age-dependent. We show that this syndrome is caused by a novel, heterozygous p.Glu11Lys mutation in the atrial-specific myosin light chain gene MYL4. In zebrafish, mutant MYL4 leads to disruption of sarcomeric structure, atrial enlargement and electrical abnormalities associated with human AF. These findings describe the cause of a rare subtype of AF due to a primary, atrial-specific sarcomeric defect. PMID:27066836

  1. An analysis of diffuse light attenuation in the northern Gulf of Mexico hypoxic zone using the SeaWiFS satellite data record

    EPA Science Inventory

    The water column diffuse attenuation coefficient (Kd) of the Louisiana Continental Shelf (LCS) was examined during ten years to characterize the spatial and temporal variations on monthly scales from 1998 to 2007. This region is well-known for summer hypoxia (dissolved oxygen < 2...

  2. Sensitivity of pathogenic and attenuated E. coli O157:H7 strains to ultraviolet-C light as assessed by conventional plating methods and ethidium monoazide-PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the UV-C sensitivity of six pathogenic E. coli O157:H7 strains associated with recent outbreaks of foodborne illnesses and four attenuated E. coli O157:H7 strains was investigated. Futhermore, the mechanism of UV-C impact on two pathogenic E. coli strains with different UV-C sensitiv...

  3. Lighting

    SciTech Connect

    Audin, L.

    1994-12-31

    EPAct covers a vast territory beyond lighting and, like all legislation, also contains numerous {open_quotes}favors,{close_quotes} compromises, and even some sleight-of-hand. Tucked away under Title XIX, for example, is an increase from 20% to 28% tax on gambling winnings, effective January 1, 1993 - apparently as a way to help pay for new spending listed elsewhere in the bill. Overall, it is a landmark piece of legislation, about a decade overdue. It remains to be seen how the Federal Government will enforce upgrading of state (or even their own) energy codes. There is no mention of funding for {open_quotes}energy police{close_quotes} in EPAct. Merely creating such a national standard, however, provides a target for those who sincerely wish to create an energy-efficient future.

  4. Disruption of the ESX-5 system of Mycobacterium tuberculosis causes loss of PPE protein secretion, reduction of cell wall integrity and strong attenuation.

    PubMed

    Bottai, Daria; Di Luca, Mariagrazia; Majlessi, Laleh; Frigui, Wafa; Simeone, Roxane; Sayes, Fadel; Bitter, Wilbert; Brennan, Michael J; Leclerc, Claude; Batoni, Giovanna; Campa, Mario; Brosch, Roland; Esin, Semih

    2012-03-01

    The chromosome of Mycobacterium tuberculosis encodes five type VII secretion systems (ESX-1-ESX-5). While the role of the ESX-1 and ESX-3 systems in M. tuberculosis has been elucidated, predictions for the function of the ESX-5 system came from data obtained in Mycobacterium marinum, where it transports PPE and PE_PGRS proteins and modulates innate immune responses. To define the role of the ESX-5 system in M. tuberculosis, in this study, we have constructed five M. tuberculosis H37Rv ESX-5 knockout/deletion mutants, inactivating eccA(5), eccD(5), rv1794 and esxM genes or the ppe25-pe19 region. Whereas the Mtbrv1794ko displayed no obvious phenotype, the other four mutants showed defects in secretion of the ESX-5-encoded EsxN and PPE41, a representative member of the large PPE protein family. Strikingly, the MtbeccD(5) ko mutant also showed enhanced sensitivity to detergents and hydrophilic antibiotics. When the virulence of the five mutants was evaluated, the MtbeccD(5) ko and MtbΔppe25-pe19 mutants were found attenuated both in macrophages and in the severe combined immune-deficient mouse infection model. Altogether these findings indicate an essential role of ESX-5 for transport of PPE proteins, cell wall integrity and full virulence of M. tuberculosis, thereby opening interesting new perspectives for the study of this human pathogen.

  5. Gene expression patterns in transgenic mouse models of hypertrophic cardiomyopathy caused by mutations in myosin regulatory light chain☆

    PubMed Central

    Huang, Wenrui; Kazmierczak, Katarzyna; Zhou, Zhiqun; Aguiar-Pulido, Vanessa; Narasimhan, Giri; Szczesna-Cordary, Danuta

    2017-01-01

    Using microarray and bioinformatics, we examined the gene expression profiles in transgenic mouse hearts expressing mutations in the myosin regulatory light chain shown to cause hypertrophic cardiomyopathy (HCM). We focused on two malignant RLC-mutations, Arginine 58→Glutamine (R58Q) and Aspartic Acid 166 → Valine (D166V), and one benign, Lysine 104 → Glutamic Acid (K104E)-mutation. Datasets of differentially expressed genes for each of three mutants were compared to those observed in wild-type (WT) hearts. The changes in the mutant vs. WT samples were shown as fold-change (FC), with stringency FC ≥ 2. Based on the gene profiles, we have identified the major signaling pathways that underlie the R58Q-, D166V- and K104E-HCM phenotypes. The correlations between different genotypes were also studied using network-based algorithms. Genes with strong correlations were clustered into one group and the central gene networks were identified for each HCM mutant. The overall gene expression patterns in all mutants were distinct from the WT profiles. Both malignant mutations shared certain classes of genes that were up or downregulated, but most similarities were noted between D166V and K104E mice, with R58Q hearts showing a distinct gene expression pattern. Our data suggest that all three HCM mice lead to cardiomyopathy in a mutation-specific manner and thus develop HCM through diverse mechanisms. PMID:26906074

  6. Combined Light Microscopy and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy for Integration of Biofilm Structure, Distribution, and Chemistry at Solid-Liquid Interfaces

    PubMed Central

    Suci, P. A.; Siedlecki, K. J.; Palmer, R. J.; White, D. C.; Geesey, G. G.

    1997-01-01

    Reflected differential interference contrast microscopy and attenuated total reflection Fourier transform infrared spectroscopy were used to obtain complementary data on the structural and chemical properties of a biofilm. This information was obtained nondestructively, quasisimultaneously, and in real time, thereby permitting the verification of time-dependent relationships between the biofilm's population structure, distribution, and interfacial chemistry. The approach offers opportunities to examine these relationships on a variety of substrata in the presence of a bulk aqueous phase under controlled hydrodynamic conditions. PMID:16535743

  7. Loss of Gata4 in Sertoli cells impairs the spermatogonial stem cell niche and causes germ cell exhaustion by attenuating chemokine signaling

    PubMed Central

    Chen, Su-Ren; Tang, Ji-Xin; Cheng, Jin-Mei; Li, Jian; Jin, Cheng; Li, Xiao-Yu; Deng, Shou-Long; Zhang, Yan; Wang, Xiu-Xia; Liu, Yi-Xun

    2015-01-01

    Sertoli cells, the primary somatic cell in the seminiferous epithelium, provide the spermatogonial stem cell (SSC) microenvironment (niche) through physical support and the expression of paracrine factors. However, the regulatory mechanisms within the SSC niche, which is primarily controlled by Sertoli cells, remain largely unknown. GATA4 is a Sertoli cell marker, involved in genital ridge initiation, sex determination and differentiation during the embryonic stage. Here, we showed that neonatal mice with a targeted disruption of Gata4 in Sertoli cells (Gata4flox/flox; Amh-Cre; hereafter termed Gata4 cKO) displayed a loss of the establishment and maintenance of the SSC pool and apoptosis of both gonocyte-derived differentiating spermatogonia and meiotic spermatocytes. Thus, progressive germ cell depletion and a Sertoli-cell-only syndrome were observed as early as the first wave of murine spermatogenesis. Transplantation of germ cells from postnatal day 5 (P5) Gata4 cKO mice into KitW/W-v recipient seminiferous tubules restored spermatogenesis. In addition, microarray analyses of P5 Gata4 cKO mouse testes showed alterations in chemokine signaling factors, including Cxcl12, Ccl3, Cxcr4 (CXCL12 receptor), Ccr1 (CCL3 receptor), Ccl9, Xcl1 and Ccrl2. Deletion of Gata4 in Sertoli cells markedly attenuated Sertoli cell chemotaxis, which guides SSCs or prospermatogonia to the stem cell niche. Finally, we showed that GATA4 transcriptionally regulated Cxcl12 and Ccl9, and the addition of CXCL12 and CCL9 to an in vitro testis tissue culture system increased the number of PLZF+ undifferentiated spermatogonia within Gata4 cKO testes. Together, these results reveal a novel role for GATA4 in controlling the SSC niche via the transcriptional regulation of chemokine signaling shortly after birth. PMID:26473289

  8. Fish Oil Attenuates Omega-6 Polyunsaturated Fatty Acid-Induced Dysbiosis and Infectious Colitis but Impairs LPS Dephosphorylation Activity Causing Sepsis

    PubMed Central

    Brown, Kirsty; Rajendiran, Ethendhar; Estaki, Mehrbod; Dai, Chuanbin; Yip, Ashley; Gibson, Deanna L.

    2013-01-01

    Clinically, excessive ω-6 polyunsaturated fatty acid (PUFA) and inadequate ω-3 PUFA have been associated with enhanced risks for developing ulcerative colitis. In rodent models, ω-3 PUFAs have been shown to either attenuate or exacerbate colitis in different studies. We hypothesized that a high ω-6: ω-3 PUFA ratio would increase colitis susceptibility through the microbe-immunity nexus. To address this, we fed post-weaned mice diets rich in ω-6 PUFA (corn oil) and diets supplemented with ω-3 PUFA (corn oil+fish oil) for 5 weeks. We evaluated the intestinal microbiota, induced colitis with Citrobacter rodentium and followed disease progression. We found that ω-6 PUFA enriched the microbiota with Enterobacteriaceae, Segmented Filamentous Bacteria and Clostridia spp., all known to induce inflammation. During infection-induced colitis, ω-6 PUFA fed mice had exacerbated intestinal damage, immune cell infiltration, prostaglandin E2 expression and C. rodentium translocation across the intestinal mucosae. Addition of ω-3 PUFA on a high ω-6 PUFA diet, reversed inflammatory-inducing microbial blooms and enriched beneficial microbes like Lactobacillus and Bifidobacteria, reduced immune cell infiltration and impaired cytokine/chemokine induction during infection. While, ω-3 PUFA supplementation protected against severe colitis, these mice suffered greater mortality associated with sepsis-related serum factors such as LPS binding protein, IL-15 and TNF-α. These mice also demonstrated decreased expression of intestinal alkaline phosphatase and an inability to dephosphorylate LPS. Thus, the colonic microbiota is altered differentially through varying PUFA composition, conferring altered susceptibility to colitis. Overall, ω-6 PUFA enriches pro-inflammatory microbes and augments colitis; but prevents infection-induced systemic inflammation. In contrast, ω-3 PUFA supplementation reverses the effects of the ω-6 PUFA diet but impairs infection-induced responses

  9. Fish oil attenuates omega-6 polyunsaturated fatty acid-induced dysbiosis and infectious colitis but impairs LPS dephosphorylation activity causing sepsis.

    PubMed

    Ghosh, Sanjoy; DeCoffe, Daniella; Brown, Kirsty; Rajendiran, Ethendhar; Estaki, Mehrbod; Dai, Chuanbin; Yip, Ashley; Gibson, Deanna L

    2013-01-01

    Clinically, excessive ω-6 polyunsaturated fatty acid (PUFA) and inadequate ω-3 PUFA have been associated with enhanced risks for developing ulcerative colitis. In rodent models, ω-3 PUFAs have been shown to either attenuate or exacerbate colitis in different studies. We hypothesized that a high ω-6: ω-3 PUFA ratio would increase colitis susceptibility through the microbe-immunity nexus. To address this, we fed post-weaned mice diets rich in ω-6 PUFA (corn oil) and diets supplemented with ω-3 PUFA (corn oil+fish oil) for 5 weeks. We evaluated the intestinal microbiota, induced colitis with Citrobacter rodentium and followed disease progression. We found that ω-6 PUFA enriched the microbiota with Enterobacteriaceae, Segmented Filamentous Bacteria and Clostridia spp., all known to induce inflammation. During infection-induced colitis, ω-6 PUFA fed mice had exacerbated intestinal damage, immune cell infiltration, prostaglandin E2 expression and C. rodentium translocation across the intestinal mucosae. Addition of ω-3 PUFA on a high ω-6 PUFA diet, reversed inflammatory-inducing microbial blooms and enriched beneficial microbes like Lactobacillus and Bifidobacteria, reduced immune cell infiltration and impaired cytokine/chemokine induction during infection. While, ω-3 PUFA supplementation protected against severe colitis, these mice suffered greater mortality associated with sepsis-related serum factors such as LPS binding protein, IL-15 and TNF-α. These mice also demonstrated decreased expression of intestinal alkaline phosphatase and an inability to dephosphorylate LPS. Thus, the colonic microbiota is altered differentially through varying PUFA composition, conferring altered susceptibility to colitis. Overall, ω-6 PUFA enriches pro-inflammatory microbes and augments colitis; but prevents infection-induced systemic inflammation. In contrast, ω-3 PUFA supplementation reverses the effects of the ω-6 PUFA diet but impairs infection-induced responses

  10. Loss of Gata4 in Sertoli cells impairs the spermatogonial stem cell niche and causes germ cell exhaustion by attenuating chemokine signaling.

    PubMed

    Chen, Su-Ren; Tang, Ji-Xin; Cheng, Jin-Mei; Li, Jian; Jin, Cheng; Li, Xiao-Yu; Deng, Shou-Long; Zhang, Yan; Wang, Xiu-Xia; Liu, Yi-Xun

    2015-11-10

    Sertoli cells, the primary somatic cell in the seminiferous epithelium, provide the spermatogonial stem cell (SSC) microenvironment (niche) through physical support and the expression of paracrine factors. However, the regulatory mechanisms within the SSC niche, which is primarily controlled by Sertoli cells, remain largely unknown. GATA4 is a Sertoli cell marker, involved in genital ridge initiation, sex determination and differentiation during the embryonic stage. Here, we showed that neonatal mice with a targeted disruption of Gata4 in Sertoli cells (Gata4(flox/flox); Amh-Cre; hereafter termed Gata4 cKO) displayed a loss of the establishment and maintenance of the SSC pool and apoptosis of both gonocyte-derived differentiating spermatogonia and meiotic spermatocytes. Thus, progressive germ cell depletion and a Sertoli-cell-only syndrome were observed as early as the first wave of murine spermatogenesis. Transplantation of germ cells from postnatal day 5 (P5) Gata4 cKO mice into Kit(W/W-v) recipient seminiferous tubules restored spermatogenesis. In addition, microarray analyses of P5 Gata4 cKO mouse testes showed alterations in chemokine signaling factors, including Cxcl12, Ccl3, Cxcr4 (CXCL12 receptor), Ccr1 (CCL3 receptor), Ccl9, Xcl1 and Ccrl2. Deletion of Gata4 in Sertoli cells markedly attenuated Sertoli cell chemotaxis, which guides SSCs or prospermatogonia to the stem cell niche. Finally, we showed that GATA4 transcriptionally regulated Cxcl12 and Ccl9, and the addition of CXCL12 and CCL9 to an in vitro testis tissue culture system increased the number of PLZF+ undifferentiated spermatogonia within Gata4 cKO testes. Together, these results reveal a novel role for GATA4 in controlling the SSC niche via the transcriptional regulation of chemokine signaling shortly after birth.

  11. Artificial light at night causes diapause inhibition and sex-specific life history changes in a moth

    PubMed Central

    van Geffen, Koert G; van Grunsven, Roy H A; van Ruijven, Jasper; Berendse, Frank; Veenendaal, Elmar M

    2014-01-01

    Rapidly increasing levels of light pollution subject nocturnal organisms to major alterations of their habitat, the ecological consequences of which are largely unknown. Moths are well-known to be attracted to light at night, but effects of light on other aspects of moth ecology, such as larval development and life-history, remain unknown. Such effects may have important consequences for fitness and thus for moth population sizes. To study the effects of artificial night lighting on development and life-history of moths, we experimentally subjected Mamestra brassicae (Noctuidae) caterpillars to low intensity green, white, red or no artificial light at night and determined their growth rate, maximum caterpillar mass, age at pupation, pupal mass and pupation duration. We found sex-specific effects of artificial light on caterpillar life-history, with male caterpillars subjected to green and white light reaching a lower maximum mass, pupating earlier and obtaining a lower pupal mass than male caterpillars under red light or in darkness. These effects can have major implications for fitness, but were absent in female caterpillars. Moreover, by the time that the first adult moth from the dark control treatment emerged from its pupa (after 110 days), about 85% of the moths that were under green light and 83% of the moths that were under white light had already emerged. These differences in pupation duration occurred in both sexes and were highly significant, and likely result from diapause inhibition by artificial night lighting. We conclude that low levels of nocturnal illumination can disrupt life-histories in moths and inhibit the initiation of pupal diapause. This may result in reduced fitness and increased mortality. The application of red light, instead of white or green light, might be an appropriate measure to mitigate negative artificial light effects on moth life history. PMID:25360250

  12. Artificial light at night causes diapause inhibition and sex-specific life history changes in a moth.

    PubMed

    van Geffen, Koert G; van Grunsven, Roy H A; van Ruijven, Jasper; Berendse, Frank; Veenendaal, Elmar M

    2014-06-01

    Rapidly increasing levels of light pollution subject nocturnal organisms to major alterations of their habitat, the ecological consequences of which are largely unknown. Moths are well-known to be attracted to light at night, but effects of light on other aspects of moth ecology, such as larval development and life-history, remain unknown. Such effects may have important consequences for fitness and thus for moth population sizes. To study the effects of artificial night lighting on development and life-history of moths, we experimentally subjected Mamestra brassicae (Noctuidae) caterpillars to low intensity green, white, red or no artificial light at night and determined their growth rate, maximum caterpillar mass, age at pupation, pupal mass and pupation duration. We found sex-specific effects of artificial light on caterpillar life-history, with male caterpillars subjected to green and white light reaching a lower maximum mass, pupating earlier and obtaining a lower pupal mass than male caterpillars under red light or in darkness. These effects can have major implications for fitness, but were absent in female caterpillars. Moreover, by the time that the first adult moth from the dark control treatment emerged from its pupa (after 110 days), about 85% of the moths that were under green light and 83% of the moths that were under white light had already emerged. These differences in pupation duration occurred in both sexes and were highly significant, and likely result from diapause inhibition by artificial night lighting. We conclude that low levels of nocturnal illumination can disrupt life-histories in moths and inhibit the initiation of pupal diapause. This may result in reduced fitness and increased mortality. The application of red light, instead of white or green light, might be an appropriate measure to mitigate negative artificial light effects on moth life history.

  13. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings

    NASA Technical Reports Server (NTRS)

    Johnson, C. F.; Brown, C. S.; Wheeler, R. M.; Sager, J. C.; Chapman, D. K.; Deitzer, G. F.

    1996-01-01

    Oat (Avena sativa cv Seger) seedlings were irradiated with IR light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum.

  14. RS9, a novel Nrf2 activator, attenuates light-induced death of cells of photoreceptor cells and Müller glia cells.

    PubMed

    Inoue, Yuki; Shimazawa, Masamitsu; Noda, Yasuhiro; Nagano, Ryota; Otsuka, Tomohiro; Kuse, Yoshiki; Nakano, Yukimichi; Tsuruma, Kazuhiro; Nakagami, Yasuhiro; Hara, Hideaki

    2017-03-27

    The retina is highly sensitive to oxidative stress because of its high consumption of oxygen associated with the phototransductional processes. Recent findings have suggested that oxidative stress is involved in the pathology of age-related macular degeneration (AMD), a progressive degeneration of the central retina. A well-known environmental risk factor is light exposure, as excessive and continuous light exposure can damage photoreceptors. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional factor that controls antioxidative responses and phase 2 enzymes. Thus, we hypothesized that RS9, a specific activator of Nrf2, decreases light-induced retinal cell death in vivo and in vitro. Nrf2 was detected in the nucleus of the 661w cells exposed to RS9 and also after light exposure, and the Nrf2-antioxidant response element (ARE) binding was increased in 661w cells after exposure to RS9. Consequentially, the expression of the phase 2 enzyme's mRNAs of Ho-1, Nqo-1, and Gclm genes were increased in 661w cells after exposure to RS9. Further, RS9 decreased the light-induced death of 661W cells (2,500 lx, 24 h), and also reduced the functional damages and the histological degeneration of the nuclei in the outer nuclear layer (ONL) or the retina in the in vivo studies (8,000 lx, 3 h). HO-1 was increased after light exposure, and Nrf2 was translocated into the nucleus after light exposure in vivo. Silencing of Ho-1 reduced the protective effects of RS9 against light-induced death of 661w cells. These findings indicate that RS9 has therapeutic potential for retinal diseases that are aggravated by light exposure. This article is protected by copyright. All rights reserved.

  15. Confocal Cornea Microscopy Detects Involvement of Corneal Nerve Fibers in a Patient with Light-Chain Amyloid Neuropathy Caused by Multiple Myeloma: A Case Report

    PubMed Central

    Sturm, Dietrich; Schmidt-Wilcke, Tobias; Greiner, Tineke; Maier, Christoph; Schargus, Marc; Tegenthoff, Martin; Vorgerd, Matthias

    2016-01-01

    Changes in the subbasal corneal plexus detected by confocal cornea microscopy (CCM) have been described for various types of neuropathy. An involvement of these nerves within light-chain (AL) amyloid neuropathy (a rare cause of polyneuropathy) has never been shown. Here, we report on a case of a patient suffering from neuropathy caused by AL amyloidosis and underlying multiple myeloma. Small-fiber damage was detected by CCM. PMID:27482195

  16. Control of pineal indole biosynthesis by changes in sympathetic tone caused by factors other than environmental lighting.

    NASA Technical Reports Server (NTRS)

    Lynch, H. J.; Eng, J. P.; Wurtman, R. J.

    1973-01-01

    Description of experimental investigations showing that, in addition to environmental lighting, other manipulations known to modify sympathetic tone can also modify pineal indole biosynthesis. Comparable alterations in sympathetic tone that occur in response to activity or feeding cycles may be instrumental in generating the pineal rhythms that persist in the absence of light-dark cycle.

  17. Geldanamycin induces production of heat shock protein 70 and partially attenuates ototoxicity caused by gentamicin in the organ of Corti explants

    PubMed Central

    2009-01-01

    Background Heat shock protein 70 (HSP70) protects inner ear cells from damage and death induced by e.g. heat or toxins. Benzoquinone ansamycin antibiotic geldanamycin (GA) was demonstrated to induce the expression of HSP70 in various animal cell types. The aim of our study was to investigate whether GA induces HSP70 in the organ of Corti (OC), which contains the auditory sensory cells, and whether GA can protect these cells from toxicity caused by a common aminoglycoside antibiotic gentamicin. Methods To address these questions, we used the OC explants isolated from p3-p5 rats. As a read-out, we used RT-PCR, ELISA and immunofluorescence. Results We found that GA at the concentration of 2 μM efficiently induced HSP70 expression on mRNA and protein level in the OC explants. Confocal microscopy revealed that HSP70 induced by GA is expressed by hair cells and interdental cells of spiral limbus. Preincubation of explants with 2 μM GA prior to adding gentamicin (500 μM) significantly reduced the loss of outer but not inner hair cells, suggesting different mechanisms of otoprotection needed for these two cell types. Conclusion GA induced HSP70 in the auditory sensory cells and partially protected them from toxicity of gentamicin. Understanding the molecular mechanisms of GA otoprotection may provide insights for preventative therapy of the hearing loss caused by aminoglycoside antibiotics. PMID:19723345

  18. Live, Attenuated Venezuelan Equine Encephalitis Virus Vaccine (TC83) Causes Persistent Brain Infection in Mice with Non-functional αβ T-Cells

    PubMed Central

    Taylor, Katherine; Kolokoltsova, Olga; Ronca, Shannon E.; Estes, Mark; Paessler, Slobodan

    2017-01-01

    Intranasal infection with vaccine strain of Venezuelan equine encephalitis virus (TC83) caused persistent viral infection in the brains of mice without functional αβ T-cells (αβ-TCR -/-). Remarkably, viral kinetics, host response gene transcripts and symptomatic disease are similar between αβ-TCR -/- and wild-type C57BL/6 (WT) mice during acute phase of infection [0–13 days post-infection (dpi)]. While WT mice clear infectious virus in the brain by 13 dpi, αβ-TCR -/- maintain infectious virus in the brain to 92 dpi. Persistent brain infection in αβ-TCR -/- correlated with inflammatory infiltrates and elevated cytokine protein levels in the brain at later time points. Persistent brain infection of αβ-TCR -/- mice provides a novel model to study prolonged alphaviral infection as well as the effects and biomarkers of long-term viral inflammation in the brain. PMID:28184218

  19. A semi-analytical model of the influence of phytoplankton community structure on the relationship between light attenuation and ocean color

    NASA Astrophysics Data System (ADS)

    Ciotti, ÁUrea M.; Cullen, John J.; Lewis, Marlon R.

    1999-01-01

    A model was developed to examine the influence of phytoplankton community structure on the relationship between diffuse attenuation and ratios of upwelling radiance. Shifts in phytoplankton communities were represented by changing mean optical properties as a function of chlorophyll (C, mg m-3), consistent with large data sets from the field and laboratory. The product of cell size and internal pigment concentration, dci, governs pigment packaging, which alters the specific absorption coefficients of phytoplankton (aph*, m2 mgChl-1). Pigment packaging was parameterized as a function of C by combining the relationship between dci and aph* from phytoplankton cultures with that between aph* and C from the field, using data for 675 nm, where absorption by accessory pigments is low. Changes in accessory pigmentation were approximated by quantifying residual variability in aph* at other wavelengths, as functions of C, once the variability with dci was taken into account. Absorption by colored dissolved organic matter (CDOM), detrital absorption, and scattering by particles were also parameterized as functions of C, so that bio-optical relationships could be modeled as functions of trophic status. The model thus reconciled recognized relationships between optical properties and C with ecologically interpretable shifts in phytoplankton communities. Empirical relationships between diffuse attenuation and ocean color were well reproduced at low (0.5 mg m-3) to medium (10 mg m-3) C. Analysis of variability imposed by a range of dci suggests that it may be possible to recognize phytoplankton communities with cell sizes and intracellular pigment concentration different from the central tendency, given a set of wavelengths which minimizes the influence of CDOM and detrital absorption.

  20. Attenuation of Phosphorylation-dependent Activation of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) by Disease-causing Mutations at the Transmission Interface*

    PubMed Central

    Chin, Stephanie; Yang, Donghe; Miles, Andrew J.; Eckford, Paul D. W.; Molinski, Steven; Wallace, B. A.; Bear, Christine E.

    2017-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a multidomain membrane protein that functions as a phosphorylation-regulated anion channel. The interface between its two cytosolic nucleotide binding domains and coupling helices conferred by intracellular loops extending from the channel pore domains has been referred to as a transmission interface and is thought to be critical for the regulated channel activity of CFTR. Phosphorylation of the regulatory domain of CFTR by protein kinase A (PKA) is required for its channel activity. However, it was unclear if phosphorylation modifies the transmission interface. Here, we studied purified full-length CFTR protein using spectroscopic techniques to determine the consequences of PKA-mediated phosphorylation. Synchrotron radiation circular dichroism spectroscopy confirmed that purified full-length wild-type CFTR is folded and structurally responsive to phosphorylation. Intrinsic tryptophan fluorescence studies of CFTR showed that phosphorylation reduced iodide-mediated quenching, consistent with an effect of phosphorylation in burying tryptophans at the transmission interface. Importantly, the rate of phosphorylation-dependent channel activation was compromised by the introduction of disease-causing mutations in either of the two coupling helices predicted to interact with nucleotide binding domain 1 at the interface. Together, these results suggest that phosphorylation modifies the interface between the catalytic and pore domains of CFTR and that this modification facilitates CFTR channel activation. PMID:28003367

  1. Attenuation of Phosphorylation-dependent Activation of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) by Disease-causing Mutations at the Transmission Interface.

    PubMed

    Chin, Stephanie; Yang, Donghe; Miles, Andrew J; Eckford, Paul D W; Molinski, Steven; Wallace, B A; Bear, Christine E

    2017-02-03

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a multidomain membrane protein that functions as a phosphorylation-regulated anion channel. The interface between its two cytosolic nucleotide binding domains and coupling helices conferred by intracellular loops extending from the channel pore domains has been referred to as a transmission interface and is thought to be critical for the regulated channel activity of CFTR. Phosphorylation of the regulatory domain of CFTR by protein kinase A (PKA) is required for its channel activity. However, it was unclear if phosphorylation modifies the transmission interface. Here, we studied purified full-length CFTR protein using spectroscopic techniques to determine the consequences of PKA-mediated phosphorylation. Synchrotron radiation circular dichroism spectroscopy confirmed that purified full-length wild-type CFTR is folded and structurally responsive to phosphorylation. Intrinsic tryptophan fluorescence studies of CFTR showed that phosphorylation reduced iodide-mediated quenching, consistent with an effect of phosphorylation in burying tryptophans at the transmission interface. Importantly, the rate of phosphorylation-dependent channel activation was compromised by the introduction of disease-causing mutations in either of the two coupling helices predicted to interact with nucleotide binding domain 1 at the interface. Together, these results suggest that phosphorylation modifies the interface between the catalytic and pore domains of CFTR and that this modification facilitates CFTR channel activation.

  2. Optical properties of urban aerosols, aircraft emissions, and heavy-duty diesel trucks using aerosol light extinction measurements by an Aerodyne Cavity Attenuated Phase Shift Particle Extinction Monitor (CAPS PMex)

    NASA Astrophysics Data System (ADS)

    Freedman, A.; Massoli, P.; Wood, E. C.; Allan, J. D.; Fortner, E.; Yu, Z.; Herndon, S. C.; Miake-Lye, R. C.; Onasch, T. B.

    2010-12-01

    We present results of optical property characterization of ambient particulate during several field deployments where measurements of aerosol light extinction (σep) are obtained using an Aerodyne Cavity Attenuated Phase Shift Particle Extinction Monitor (CAPS PMex). The CAPS PMex is able to provide extinction measurements with 3-σ detection limit of 3 Mm-1 for 1s integration time. The CAPS PMex (630 nm) is integrated in the Aerodyne Research, Inc. (ARI) mobile laboratory where a co-located Multi Angle Absorption Photometer (MAAP) provides particle light absorption coefficient at 632 nm. The combination of the CAPS with the MAAP data allows estimating the single scattering albedo (ω) of the ambient aerosol particles. The ARI mobile laboratory was deployed in winter 2010 at the Chicago O’Hare International Airport to measure gas phase and particulate emissions from different aircraft engines, and during summer 2010 in Oakland, CA, to characterize vehicular gaseous and particulate emissions (mainly exhaust from heavy-duty diesel trucks) from the Caldecott Tunnel. We provide estimates of black carbon emission factors from individual aircraft engines and diesel trucks, in addition to characterizing the optical properties of these ambient samples studying fleet-average emissions for both light-duty passenger vehicles and heavy-duty diesel trucks. Two CAPS PMex instruments (measuring σep at 630 and 532 nm) were also deployed during the CalNex 2010 study (May 14 - June 16) at the CalTech ground site in Pasadena, CA. During the same time, a photo-acoustic spectrometer (PAS, DMT) and an aethalometer instrument (Magee Sci.) measured particle light absorption of submicron aerosol particles from the same sample line as the CAPS PMex monitors. We combine these data to provide multi-wavelength ω trends for the one-month campaign. Our results show the high potential of the CAPS as light weight, compact instrument to perform precise and accurate σep measurements of

  3. Folic Acid Attenuates Vascular Endothelial Cell Injury Caused by Hypoxia via the Inhibition of ERK1/2/NOX4/ROS Pathway.

    PubMed

    Cheng, Fei; Lan, Jun; Xia, Wenhao; Tu, Chang; Chen, Benfa; Li, Shicheng; Pan, Weibiao

    2016-06-01

    Coronary artery disease is a disease with high morbidity and mortality, in which vascular endothelial dysfunction plays an important role. Hypoxia leads to the inflammation and oxidative stress in endothelial cells, which results in the endothelial injury. The present study was designed to investigate the protective effect and mechanism of folic acid on hypoxia-induced injury in human umbilical vein endothelial cells (HUVEC). Cell counting Kit was used to detect cell survival rate, and apoptotic cells were detected by Hoechst 33258 staining. Intracellular reactive oxygen species (ROS) level was measured using dichloro-dihydro-fluorescein diacetate staining. Western blot was used to determine the protein expressions of extracellular signal protein kinase 1/2 (ERK1/2) and phosphorylated ERK1/2 (p-ERK1/2), NOX4 subunit of NAPDH and endothelial nitric oxide synthase (eNOS). Folic acid significantly increased the cell survival rate and decreased the apoptosis of HUVECs treated with folic acid compared with hypoxia-treated HUVEC. Folic acid also decreased ROS level, while it increased the nitrite content in HUVECs. In addition, folic acid decreased protein expressions of NOX4 and p-ERK1/2, while it increased the protein expression of eNOS in HUVECs. Furthermore, N-acetyl cysteine (NAC), the antioxidant, had similar effect on the cell survival rate and the apoptosis. In addition, DPI (NOX4 inhibitor) and U0126 (ERK1/2 inhibitor) rather than NAC decreased the protein expression of NOX4. NAC, DPI, and U0126 increased the protein expression of eNOS. Furthermore, U0126 rather than DPI and NAC decreased the protein expression of p-ERK1/2. Taken together, the results suggested that hypoxia decreased the cell survival rate and induced apoptosis via ERK1/2/NOX4/ROS pathway, which could be the target of folic acid in protecting the HUVECs from injury caused by hypoxia.

  4. Mapping Lateral Pn Attenuation Variation in Asia

    NASA Astrophysics Data System (ADS)

    Yang, X.; Phillips, W. S.; Randall, G. E.

    2009-12-01

    Pn travels most of its path in the uppermost mantle. Mapping of the lateral variation of Pn amplitude attenuation may shed light on the physical and chemical state, and dynamics of the upper mantle. In addition to material attenuation, Pn amplitudes are affected by other factors including the spherical shape of the Earth and Moho topography. In order to derive reliable Pn attenuation, we adopt a frequency-dependent Pn geometric-spreading model, which was designed to account for the effect of the Earth’s sphericity, to correct Pn amplitudes in preparation for attenuation estimation. We obtain physically reasonable attenuation estimates from Pn amplitudes corrected using the new spreading model. Pn amplitudes corrected using the traditional frequency-independent power-law spreading model, on the other hand, yield attenuation estimates that are either too large or negative. Using properly geometric-spreading corrected Pn amplitudes, we conducted attenuation tomography and developed 2D Pn attenuation models at multiple frequencies from 0.5 Hz to 8 Hz for Asia. Overall Pn attenuation patterns correlate, to some degree, with our current knowledge of the state of the upper mantle of the region. We see consistent low attenuation in cratonic regions and high attenuation along the western Pacific Ocean. The attenuation pattern in the Tibetan Plateau region seems to be frequency dependent with high attenuation around 1 Hz and low attenuation at 8 Hz. Application of the attenuation model to the nuclear-explosion discrimination problem leads to appreciable improvements of the discriminant compared with currently adopted method.

  5. Irreversible photoinhibition of photosystem II is caused by exposure of Synechocystis cells to strong light for a prolonged period.

    PubMed

    Allakhverdiev, Suleyman I; Tsvetkova, Nelly; Mohanty, Prasanna; Szalontai, Balász; Moon, Byoung Yong; Debreczeny, Mónika; Murata, Norio

    2005-07-15

    Irreversible photoinhibition of photosystem II (PSII) occurred when Synechocystis sp. PCC 6803 cells were exposed to very strong light for a prolonged period. When wild-type cells were illuminated at 20 degrees C for 2 h with light at an intensity of 2,500 micromol photons m(-2) s(-1), the oxygen-evolving activity of PSII was almost entirely and irreversibly lost, whereas the photochemical reaction center in PSII was inactivated only reversibly. The extent of irreversible photoinhibition was enhanced at lower temperatures and by the genetically engineered rigidification of membrane lipids. Western and Northern blotting demonstrated that, after cells had undergone irreversible photoinhibition, the precursor to D1 protein in PSII was synthesized but not processed properly. These observations may suggest that exposure of Synechocystis cells to strong light results in the irreversible photoinhibition of the oxygen-evolving activity of PSII via impairment of the processing of pre-D1 and that this effect of strong light is enhanced by the rigidification of membrane lipids.

  6. Spatial and spectral image distortions caused by diffraction of an ordinary polarised light beam by an ultrasonic wave

    SciTech Connect

    Machikhin, A S; Pozhar, V E

    2015-02-28

    We consider the problem of determining the spatial and spectral image distortions arising from anisotropic diffraction by ultrasonic waves in crystals with ordinary polarised light (o → e). By neglecting the small-birefringence approximation, we obtain analytical solutions that describe the dependence of the diffraction angles and wave mismatch on the acousto-optic (AO) interaction geometry and crystal parameters. The formulas derived allow one to calculate and analyse the magnitude of diffraction-induced spatial and spectral image distortions and to identify the main types of distortions: chromatic compression and trapezoidal deformation. A comparison of the values of these distortions in the diffraction of ordinary and extraordinary polarised light shows that they are almost equal in magnitude and opposite in signs, so that consistent diffraction (o → e → o or e → o → e) in two identical AO cells rotated through 180° in the plane of diffraction can compensate for these distortions. (diffraction of radiation)

  7. Calculation Of Pneumatic Attenuation In Pressure Sensors

    NASA Technical Reports Server (NTRS)

    Whitmore, Stephen A.

    1991-01-01

    Errors caused by attenuation of air-pressure waves in narrow tubes calculated by method based on fundamental equations of flow. Changes in ambient pressure transmitted along narrow tube to sensor. Attenuation of high-frequency components of pressure wave calculated from wave equation derived from Navier-Stokes equations of viscous flow in tube. Developed to understand and compensate for frictional attenuation in narrow tubes used to connect aircraft pressure sensors with pressure taps on affected surfaces.

  8. An empirical model that uses light attenuation and plant nitrogen status to predict within-canopy nitrogen distribution and upscale photosynthesis from leaf to whole canopy

    PubMed Central

    Louarn, Gaëtan; Frak, Ela; Zaka, Serge; Prieto, Jorge; Lebon, Eric

    2015-01-01

    Modelling the spatial and temporal distribution of leaf nitrogen (N) is central to specify photosynthetic parameters and simulate canopy photosynthesis. Leaf photosynthetic parameters depend on both local light availability and whole-plant N status. The interaction between these two levels of integration has generally been modelled by assuming optimal canopy functioning, which is not supported by experiments. During this study, we examined how a set of empirical relationships with measurable parameters could be used instead to predict photosynthesis at the leaf and whole-canopy levels. The distribution of leaf N per unit area (Na) within the canopy was related to leaf light irradiance and to the nitrogen nutrition index (NNI), a whole-plant variable accounting for plant N status. Na was then used to determine the photosynthetic parameters of a leaf gas exchange model. The model was assessed on alfalfa canopies under contrasting N nutrition and with N2-fixing and non-fixing plants. Three experiments were carried out to parameterize the relationships between Na, leaf irradiance, NNI and photosynthetic parameters. An additional independent data set was used for model evaluation. The N distribution model showed that it was able to predict leaf N on the set of leaves tested. The Na at the top of the canopy appeared to be related linearly to the NNI, whereas the coefficient accounting for N allocation remained constant. Photosynthetic parameters were related linearly to Na irrespective of N nutrition and the N acquisition mode. Daily patterns of gas exchange were simulated accurately at the leaf scale. When integrated at the whole-canopy scale, the model predicted that raising N availability above an NNI of 1 did not result in increased net photosynthesis. Overall, the model proposed offered a solution for a dynamic coupling of leaf photosynthesis and canopy N distribution without requiring any optimal functioning hypothesis. PMID:26433705

  9. An empirical model that uses light attenuation and plant nitrogen status to predict within-canopy nitrogen distribution and upscale photosynthesis from leaf to whole canopy.

    PubMed

    Louarn, Gaëtan; Frak, Ela; Zaka, Serge; Prieto, Jorge; Lebon, Eric

    2015-10-03

    Modelling the spatial and temporal distribution of leaf nitrogen (N) is central to specify photosynthetic parameters and simulate canopy photosynthesis. Leaf photosynthetic parameters depend on both local light availability and whole-plant N status. The interaction between these two levels of integration has generally been modelled by assuming optimal canopy functioning, which is not supported by experiments. During this study, we examined how a set of empirical relationships with measurable parameters could be used instead to predict photosynthesis at the leaf and whole-canopy levels. The distribution of leaf N per unit area (Na) within the canopy was related to leaf light irradiance and to the nitrogen nutrition index (NNI), a whole-plant variable accounting for plant N status. Na was then used to determine the photosynthetic parameters of a leaf gas exchange model. The model was assessed on alfalfa canopies under contrasting N nutrition and with N2-fixing and non-fixing plants. Three experiments were carried out to parameterize the relationships between Na, leaf irradiance, NNI and photosynthetic parameters. An additional independent data set was used for model evaluation. The N distribution model showed that it was able to predict leaf N on the set of leaves tested. The Na at the top of the canopy appeared to be related linearly to the NNI, whereas the coefficient accounting for N allocation remained constant. Photosynthetic parameters were related linearly to Na irrespective of N nutrition and the N acquisition mode. Daily patterns of gas exchange were simulated accurately at the leaf scale. When integrated at the whole-canopy scale, the model predicted that raising N availability above an NNI of 1 did not result in increased net photosynthesis. Overall, the model proposed offered a solution for a dynamic coupling of leaf photosynthesis and canopy N distribution without requiring any optimal functioning hypothesis.

  10. A spontaneous mutation in kdsD, a biosynthesis gene for 3 Deoxy-D-manno-Octulosonic Acid, occurred in a ciprofloxacin resistant strain of Francisella tularensis and caused a high level of attenuation in murine models of tularemia.

    PubMed

    Chance, Taylor; Chua, Jennifer; Toothman, Ronald G; Ladner, Jason T; Nuss, Jonathan E; Raymond, Jo Lynne; Biot, Fabrice V; Demons, Samandra; Miller, Lynda; Halasohoris, Stephanie; Mou, Sherry; Koroleva, Galina; Lovett, Sean; Palacios, Gustavo; Vietri, Nicholas J; Worsham, Patricia L; Cote, Christopher K; Kijek, Todd M; Bozue, Joel A

    2017-01-01

    Francisella tularensis, a gram-negative facultative intracellular bacterial pathogen, is the causative agent of tularemia and able to infect many mammalian species, including humans. Because of its ability to cause a lethal infection, low infectious dose, and aerosolizable nature, F. tularensis subspecies tularensis is considered a potential biowarfare agent. Due to its in vitro efficacy, ciprofloxacin is one of the antibiotics recommended for post-exposure prophylaxis of tularemia. In order to identify therapeutics that will be efficacious against infections caused by drug resistant select-agents and to better understand the threat, we sought to characterize an existing ciprofloxacin resistant (CipR) mutant in the Schu S4 strain of F. tularensis by determining its phenotypic characteristics and sequencing the chromosome to identify additional genetic alterations that may have occurred during the selection process. In addition to the previously described genetic alterations, the sequence of the CipR mutant strain revealed several additional mutations. Of particular interest was a frameshift mutation within kdsD which encodes for an enzyme necessary for the production of 3-Deoxy-D-manno-Octulosonic Acid (KDO), an integral component of the lipopolysaccharide (LPS). A kdsD mutant was constructed in the Schu S4 strain. Although it was not resistant to ciprofloxacin, the kdsD mutant shared many phenotypic characteristics with the CipR mutant, including growth defects under different conditions, sensitivity to hydrophobic agents, altered LPS profiles, and attenuation in multiple models of murine tularemia. This study demonstrates that the KdsD enzyme is essential for Francisella virulence and may be an attractive therapeutic target for developing novel medical countermeasures.

  11. A spontaneous mutation in kdsD, a biosynthesis gene for 3 Deoxy-D-manno-Octulosonic Acid, occurred in a ciprofloxacin resistant strain of Francisella tularensis and caused a high level of attenuation in murine models of tularemia

    PubMed Central

    Chance, Taylor; Toothman, Ronald G.; Nuss, Jonathan E.; Raymond, Jo Lynne; Biot, Fabrice V.; Demons, Samandra; Miller, Lynda; Halasohoris, Stephanie; Mou, Sherry; Koroleva, Galina; Lovett, Sean; Palacios, Gustavo; Vietri, Nicholas J.; Worsham, Patricia L.; Cote, Christopher K.; Kijek, Todd M.; Bozue, Joel A.

    2017-01-01

    Francisella tularensis, a gram–negative facultative intracellular bacterial pathogen, is the causative agent of tularemia and able to infect many mammalian species, including humans. Because of its ability to cause a lethal infection, low infectious dose, and aerosolizable nature, F. tularensis subspecies tularensis is considered a potential biowarfare agent. Due to its in vitro efficacy, ciprofloxacin is one of the antibiotics recommended for post-exposure prophylaxis of tularemia. In order to identify therapeutics that will be efficacious against infections caused by drug resistant select-agents and to better understand the threat, we sought to characterize an existing ciprofloxacin resistant (CipR) mutant in the Schu S4 strain of F. tularensis by determining its phenotypic characteristics and sequencing the chromosome to identify additional genetic alterations that may have occurred during the selection process. In addition to the previously described genetic alterations, the sequence of the CipR mutant strain revealed several additional mutations. Of particular interest was a frameshift mutation within kdsD which encodes for an enzyme necessary for the production of 3-Deoxy-D-manno-Octulosonic Acid (KDO), an integral component of the lipopolysaccharide (LPS). A kdsD mutant was constructed in the Schu S4 strain. Although it was not resistant to ciprofloxacin, the kdsD mutant shared many phenotypic characteristics with the CipR mutant, including growth defects under different conditions, sensitivity to hydrophobic agents, altered LPS profiles, and attenuation in multiple models of murine tularemia. This study demonstrates that the KdsD enzyme is essential for Francisella virulence and may be an attractive therapeutic target for developing novel medical countermeasures. PMID:28328947

  12. Overexpression of metallothionein-I, a copper-regulating protein, attenuates intracellular copper dyshomeostasis and extends lifespan in a mouse model of amyotrophic lateral sclerosis caused by mutant superoxide dismutase-1.

    PubMed

    Tokuda, Eiichi; Okawa, Eriko; Watanabe, Shunsuke; Ono, Shin-Ichi

    2014-03-01

    Over 170 mutations in superoxide dismutase-1 (SOD1) cause familial amyotrophic lateral sclerosis (ALS), a lethal motor neuron disease. Although the molecular properties of SOD1 mutants differ considerably, we have recently shown that intracellular copper dyshomeostasis is a common pathogenic feature of different SOD1 mutants. Thus, the potentiation of endogenous copper regulation could be a therapeutic strategy. In this study, we investigated the effects of the overexpression of metallothionein-I (MT-I), a major copper-regulating protein, on the disease course of a mouse model of ALS (SOD1(G93A)). Using double transgenic techniques, we found that the overexpression of MT-I in SOD1(G93A) mice significantly extended the lifespan and slowed disease progression, but the effects on disease onset were modest. Genetically induced MT-I normalized copper dyshomeostasis in the spinal cord without influencing SOD1 enzymatic activity. The overexpression of MT-I in SOD1(G93A) mice markedly attenuated the pathological features of the mice, including the death of motor neurons, the degeneration of ventral root axons, the atrophy of skeletal muscles, and the activation of glial cells. Double transgenic mice also showed a decreased level of SOD1 aggregates within the glial cells of the spinal cord. Furthermore, the overexpression of MT-I in SOD1(G93A) mice reduced the number of spheroid-shaped astrocytes cleaved by active caspase-3. We concluded that therapeutic strategies aimed at the potentiation of copper regulation by MT-I could be of benefit in cases of ALS caused by SOD1 mutations.

  13. DC attenuation meter

    DOEpatents

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  14. Comparison of tissue damage caused by various laser systems with tissue tolerable plasma by light and laser scan microscopy

    NASA Astrophysics Data System (ADS)

    Vandersee, Staffan; Lademann, Jürgen; Richter, Heike; Patzelt, Alexa; Lange-Asschenfeldt, Bernhard

    2013-10-01

    Tissue tolerable plasma (TTP) represents a novel therapeutic method with promising capabilities in the field of dermatological interventions, in particular disinfection but also wound antisepsis and regeneration. The energy transfer by plasma into living tissue is not easily educible, as a variety of features such as the medium’s actual molecule-stream, the ions, electrons and free radicals involved, as well as the emission of ultraviolet, visible and infrared light contribute to its increasingly well characterized effects. Thus, relating possible adversary effects, especially of prolonged exposure to a single component of the plasma’s mode of action, is difficult. Until now, severe adverse events connected to plasma exposure have not been reported when conducted according to existing therapeutic protocols. In this study, we have compared the tissue damage-potential of CO2 and dye lasers with TTP in a porcine model. After exposure of pig ear skin to the three treatment modalities, all specimens were examined histologically and by means of laser scan microscopy (LSM). Light microscopical tissue damage could only be shown in the case of the CO2 laser, whereas dye laser and plasma treatment resulted in no detectable impairment of the specimens. In the case of TTP, LSM examination revealed only an impairment of the uppermost corneal layers of the skin, thus stressing its safety when used in vivo.

  15. Mutated olfactomedin 1 in the interphotoreceptor matrix of the mouse retina causes functional deficits and vulnerability to light damage.

    PubMed

    Koch, Marcus A; Rosenhammer, Bernd; Paper, Walter; Volz, Cornelia; Braunger, Barbara M; Hausberger, Johanna; Jägle, Herbert; Tamm, Ernst R

    2017-04-01

    Olfactomedin 1 (OLFM1) is a secreted glycoprotein and member of the olfactomedin protein family, which is preferentially expressed in various areas throughout the central nervous system. To learn about the functional properties of OLFM1 in the eye, we investigated its localization in the mouse and pig eye. In addition, we analyzed the ocular phenotype of Olfm1 mutant mice in which 52 amino acids were deleted in the central part (M2 region) of OLFM1. OLFM1 was detected in cornea, sclera, retina, and optic nerve of both wild-type and Olfm1 mutant littermates. By immunohistochemistry and double labeling with the lectin peanut agglutinin, OLFM1 was found in the interphotoreceptor matrix (IPM) of mouse and pig retina where it was directly localized to the inner segments of photoreceptors. Western blotting confirmed the presence of the OLFM1 isoforms pancortin 1 (BMY) and pancortin 2 (BMZ) in the IPM. The retinal phenotype of Olfm1 mutant mice did not obviously differ from that of wild-type littermates. In addition, outer nuclear layer (ONL) and total retinal thickness were not different, and the same was true for the area of the optic nerve in cross sections. Functional changes were observed though by electroretinography, which showed significantly lower a- and b-wave amplitudes in Olfm1 mutant mice when compared to age-matched wild-type mice. When light damage experiments were performed as an experimental paradigm of photoreceptor apoptosis, significantly more TUNEL-positive cells were observed in Olfm1 mutant mice 30 h after light exposure. One week after light exposure, the ONL was significantly thinner in Olfm1 mutant mice than in wild-type littermates indicating increased photoreceptor loss. No differences were observed when rhodopsin turnover or ERK1/2 signaling was investigated. We conclude that OLFM1 is a newly identified IPM molecule that serves an important role for photoreceptor homeostasis, which is significantly compromised in the eyes of Olfm1 mutant mice.

  16. The investigation of the light radiation caused polyethylene based materials deterioration by means of atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Sikora, A.; Grabarek, A.; Moroń, L.; Wałecki, M.; Kryla, P.

    2016-02-01

    The impact of the environmental conditions on the materials used in various devices and constructions, in particular in electrotechnical applications, has an critical impact in terms of their reliability and utilization range in specific climatic conditions. Due to increasing utilitarian requirements, technological processes complexity and introducing new materials (for instance nanomaterials), advanced diagnostic techniques are desired. One of such techniques is atomic force microscopy (AFM), which allows to study the changes of the roughness and mechanical properties of the surface at the submicrometer scale, enabling the investigation of the degradation processes. In this work the deterioration of selected group of polyethylene based materials have been measured by means of AFM, as the samples were exposed to the simulated solar light and UV-C radiation. Such an analysis of the environmental conditions impact on the deterioration process using AFM methods for various versions of specific material was not presented before.

  17. Spectral anomalies of the light-induced drift of rubidium atoms caused by the velocity dependence of transport collision frequencies

    NASA Astrophysics Data System (ADS)

    Parkhomenko, A. I.; Shalagin, A. M.

    2014-02-01

    The spectral features of the light-induced drift (LID) velocity for rubidium atoms (85Rb and 87Rb) in an argon buffer medium and in binary buffer mixtures of noble gases (Ne + Ar, Ne + Kr, Ne + Xe, He + Ar, He + Kr, and He + Xe) have been investigated theoretically. A strong temperature dependence of the spectral shape of the LID signal for Rb atoms in an Ar atmosphere is predicted in the temperature range 450 K < T < 800 K. It is shown that the anomalous LID of Rb atoms in binary buffer mixtures of noble gases can be observed at almost any temperature (including the room one) depending on the fractions of neon or helium in these mixtures. The results obtained enable a highly accurate testing of the interatomic interaction potentials used to calculate the drift velocity for anomalous LID in LID experiments.

  18. Quercetin and vitamin E attenuate Bonny Light crude oil-induced alterations in testicular apoptosis, stress proteins and steroidogenic acute regulatory protein in Wistar rats.

    PubMed

    Ebokaiwe, Azubuike P; Mathur, Premendu P; Farombi, Ebenezer O

    2016-10-01

    Studies have shown the reproductive effects of Bonny Light crude oil (BLCO) via the mechanism of oxidative stress and testicular apoptosis. We investigated the protective role of quercetin and vitamin E on BLCO-induced testicular apoptosis. Experimental rats were divided into four groups of four each. Animals were orally administered 2 ml/kg corn oil (control: group 1), BLCO-800 mg/kg body weight + 10 mg/kg quercetin (group 2), BLCO-800 mg/kg body weight + 50 mg/kg vitamin E (group 3) and BLCO-800 mg/kg body weight only (group 4) for 7 d. Protein levels of caspase 3, FasL, NF-kB, steroidogenic acute regulatory protein and stress response proteins were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunofluorescence staining was used to quantify the expression of caspase 3, FasL and NF-kB. Apoptosis was quantified by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. Administration of BLCO resulted in a significant increase in the levels of stress response proteins and apoptosis-related proteins by 50% and above after 7 d following BLCO exposure and a concomitant increase in expression of caspase 3, FasL and NF-kB expression by immunofluorescence staining. Apoptosis showed a significant increase in TUNEL positive cells. Co-administration with quercetin or vitamin E reversed BLCO-induced apoptosis and levels of stress protein, relative to control. These findings suggest that quercetin and vitamin E may confer protection against BLCO-induced testicular oxidative stress-related apoptosis.

  19. HIGHER FREQUENCY ULTRASONIC LIGHT MODULATORS.

    DTIC Science & Technology

    LIGHT ), (*MODULATORS, (*ULTRASONIC RADIATION, MODULATORS), OPTICAL COMMUNICATIONS, BANDWIDTH, TRANSDUCERS, HIGH FREQUENCY, VERY HIGH FREQUENCY, ATTENUATION, DATA PROCESSING, OPTICAL EQUIPMENT, ANALOG COMPUTERS, THEORY.

  20. Rear-surface light intensification caused by a Hertzian-conical crack in 355-nm silica optics

    NASA Astrophysics Data System (ADS)

    Zhang, Chun-Lai; Yuan, Xiao-Dong; Xiang, Xia; Wang, Zhi-Guo; Liu, Chun-Ming; Li, Li; He, Shao-Bo; Zu, Xiao-Tao

    2012-09-01

    Theoretical studies show that a Hertzian-conical crack can be considered to be composed of double cone faces for simplicity. In the present study, the three-dimensional finite-difference time-domain method is employed to quantify the electric-field distribution within the subsurface in the presence of such a defect under normal incidence irradiation. Both impurities (inside the crack) and the chemical etching have been investigated. The results show that the maximum electric field amplitude |E|max is 9.57374 V/m when the relative dielectric constant of transparent impurity equals 8.5. And the near-field modulation will be improved if the crack is filled with the remainder polishing powders or water vapor/drops. Meanwhile, the laser-induced initial damage moves to the glass—air surface. In the etched section, the magnitude of intensification is strongly dependent on the inclination angle θ. There will be a highest modulation when θ is around π/6, and the maximum value of |E|max is 18.57314 V/m. When θ ranges from π/8 to π/4, the light intensity enhancement factor can easily be larger than 100, and the modulation follows a decreasing trend. On the other hand, the modulation curves become smooth when θ > π/4 or θ < π/8.

  1. Myocardial infarction with "clean coronaries" caused by amyloid light-chain AL amyloidosis: a case report and literature review.

    PubMed

    Tsai, Stephanie B; Seldin, David C; Wu, Hao; O'Hara, Carl; Ruberg, Frederick L; Sanchorawala, Vaishali

    2011-09-01

    In AL (amyloid light-chain) amyloidosis, the greatest risk of death occurs in patients with cardiac involvement, who typically develop diastolic dysfunction and then systolic heart failure, with predisposition to arrhythmias and sudden death. Here, we present an alternate variation of cardiac amyloidosis. This patient had recent non-obstructive coronary angiography, yet suffered a fatal myocardial infarction shortly after stem cell collection and mobilization in preparation for treatment with high-dose melphalan and autologous stem cell transplantation (HDM/SCT). On autopsy, widespread deposition of amyloid was found in the small vessels of the heart with evidence of associated acute infarction. While the typical presentation of cardiac amyloidosis is an infiltrating restrictive cardiomyopathy, this case report and literature review illustrate that ischemic small vessel amyloidosis may also occur. Small vessel coronary disease and associated myocardial ischemia should be considered in patients with AL amyloidosis with angina, as its presence may increase treatment-related complications. Contemporary testing should aim to detect both forms of cardiac amyloidosis, which may impact management and prognosis.

  2. [Surgical peculiarities of gunshot injuries to arteries of the extremities caused by modern small arms and light weapons].

    PubMed

    Samokhvalov, I M; Reva, V A; Denisov, A V; Ozeretskovskiĭ, L B; Pronchenko, A A

    2014-10-01

    The aim of the given study was development of surgical tactics in case of femoral artery injury, caused by medium-calibre bullet, on the basis acute experiment on large biological objects. Experimental animals were shot into mid third of the femora by a rifle cartridge in 7,62-mm calibre (AK-47 made in 1943). The analysis of microstructure, made in 5 cross-sections performed every 1-centimetre way from the wound canal, showed that there were no any damages of arterial wall. Authors came to conclusion that the surgical debridement of the gunshot wound, made by a rifle cartridge in 7,62-mm calibre of AK-47, should consist of exsection of devitalized section of artery.

  3. Pressure surge attenuator

    DOEpatents

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  4. RADAR ATTENUATION BY SOLID-PROPELLANT-ROCKET EXHAUST.

    DTIC Science & Technology

    source of attenuation with both plastisol -nitrocellulose and inert-binder composite propellants. Aluminum is a second major cause of radar attenuation...concentrations and collision frequencies in the product gases; for plastisol -nitrocellulose propellants attenuation at one frequency can be inferred from measured

  5. Tracer attenuation in groundwater

    NASA Astrophysics Data System (ADS)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  6. Biological effects caused by low-power laser light in the treatment of the dentition, periodontium, and mucosa of oral cavity, and lip diseases

    NASA Astrophysics Data System (ADS)

    Kunin, Anatoly A.; Erina, Stanislava V.; Kashuba, Victor A.; Pankova, Svetlana N.; Stepanov, Nicolay N.; Kazmina, Svetlana G.; Dergunova, Elvira I.; Buerger, F.; Herdt, Alexander; Podolskaya, Elana E.; Shumilovitch, Bogdan R.; Ippolitov, Yu. A.; Tchernov, V. I.

    1997-12-01

    Nowadays low-power therapy is one of the leading trends in a combined treatment of the oral cavity and lips diseases. The present paper sums up the results of the investigation into the biological effects caused by low-power laser light (LPLL) during its interaction with hard and soft tissues of the oral cavity and lips. A research on the effect of LPLL upon the remineralization processes in the hard dental tissues in the stage in the stage of an initial caries was carried out in 150 patients. The biological effects caused by an interaction of LPLL with the parodontium tissues in the process of treatment of medium degree disease of the parodontium were studied in 140 patients; the effects of the above mentioned character which generated in lips tissues during treatment of a post-radiation chilitis were analyzed in 32 patients. Immunological, biochemical histochemical, morphological, stomatoscopic, bacteriological and other methods were employed while studying the bioeffects caused by LPLL in the parodontium, lips tissues and hard tissues of the tooth.

  7. Iron Loading-Induced Aggregation and Reduction of Iron Incorporation in Heteropolymeric Ferritin Containing a Mutant Light Chain that Causes Neurodegeneration

    PubMed Central

    Muhoberac, Barry B.; Baraibar, Martin A.; Vidal, Ruben

    2010-01-01

    Hereditary Ferritinopathy (HF) is a neurodegenerative disease characterized by intracellular ferritin inclusion bodies (IBs) and iron accumulation throughout the central nervous system. Ferritin IBs are composed of mutant ferritin light chain as well as wild type light (Wt-FTL) and heavy chain (FTH1) polypeptides. In vitro studies have shown that the mutant light chain polypeptide p.Phe167SerfsX26 (Mt-FTL) forms soluble ferritin 24-mer homopolymers having a specific structural disruption that explains its functional problems of reduced ability to incorporate iron and aggregation during iron loading. However, because ferritins are usually 24-mer heteropolymers and all three polypeptides are found in IBs, we investigated the properties of Mt-FTL/FTH1 and Mt-FTL/Wt-FTL heteropolymeric ferritins. We show here the facile assembly of Mt-FTL and FTH1 subunits into soluble ferritin heteropolymers, but their ability to incorporate iron was significantly reduced relative to Wt-FTL/FTH1 heteropolymers. In addition, Mt-FTL/FTH1 heteropolymers formed aggregates during iron loading, contrasting Wt-FTL/FTH1 heteropolymers and similar to what was seen for Mt-FTL homopolymers. The resulting precipitate contained both Mt-FTL and FTH1 polypeptides as do ferritin IBs in patients with HF. The presence of Mt-FTL subunits in Mt-FTL/Wt-FTL heteropolymers also caused iron loading-induced aggregation relative to Wt-FTL homopolymers, with the precipitate containing Mt- and Wt-FTL polypeptides again paralleling HF. Our data demonstrate that co-assembly with wild type subunits does not circumvent the functional problems caused by mutant subunits. Furthermore, the functional problems characterized here in heteropolymers that contain mutant subunits parallel those problems previously reported in homopolymers composed exclusively of mutant subunits, which strongly suggests that the structural disruption characterized previously in Mt-FTL homopolymers occurs in a similar manner and to a

  8. Variable laser attenuator

    DOEpatents

    Foltyn, Stephen R.

    1988-01-01

    The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

  9. Variable laser attenuator

    DOEpatents

    Foltyn, S.R.

    1987-05-29

    The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

  10. Topical and Intradermal Efficacy of Photodynamic Therapy with Methylene Blue and Light-Emitting Diode in the Treatment of Cutaneous Leishmaniasis Caused by Leishmania braziliensis

    PubMed Central

    Sbeghen, Mônica Raquel; Voltarelli, Evandra Maria; Campois, Tácito Graminha; Kimura, Elza; Aristides, Sandra Mara Alessi; Hernandes, Luzmarina; Caetano, Wilker; Hioka, Noboru; Lonardoni, Maria Valdrinez Campana; Silveira, Thaís Gomes Verzignassi

    2015-01-01

    Introduction: The topical and intradermal photodynamic therapy (PDT) effect of methylene blue (MB) using light-emitting diode (LED) as light source (MB/LED-PDT) in the treatment of lesions of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis in hamsters were investigated. Methods: Hamsters were infected in the footpad with 4×107 promastigotes of L. braziliensis and divided in 4 groups: Control group was not treated, AmB group was treated with amphotericin B, MB-Id group received intradermal MB at the edge of the lesion and MB-Tp group received MB topic. After treatment with MB, the animals were illuminated using red LEDs at the 655 nm wavelength for 1 hour. The MB/LED-PDT was carried out three times a week for 12 weeks. Results: Animals of MB-Tp group presented lesion healing with significant diminution in extent of the lesion, and reduced parasite burden compared to control group; however, no significant difference was seen compared to the AmB group. MB-Tp group also showed reconstitution of the epithelium, the formation of collagen fibers, organization in the epidermis, a little disorganization and inflammation in the dermis. MB-Id was ineffective in all parameters evaluated, and it was comparable to the control group results. Conclusion: These data show that PDT with the use of MB-Tp and LED may be an alternative for the treatment of ACL. However, additional studies are being conducted to assess the potential of MB/LED-PDT, alone or in combination with conventional therapy, for the treatment of ACL. PMID:26464777

  11. Attention Wins over Sensory Attenuation in a Sound Detection Task

    PubMed Central

    Cao, Liyu; Gross, Joachim

    2015-01-01

    ‘Sensory attenuation’, i.e., reduced neural responses to self-induced compared to externally generated stimuli, is a well-established phenomenon. However, very few studies directly compared sensory attenuation with attention effect, which leads to increased neural responses. In this study, we brought sensory attenuation and attention together in a behavioural auditory detection task, where both effects were quantitatively measured and compared. The classic auditory attention effect of facilitating detection performance was replicated. When attention and sensory attenuation were both present, attentional facilitation decreased but remained significant. The results are discussed in the light of current theories of sensory attenuation. PMID:26302246

  12. Intravascular near-infrared fluorescence catheter with ultrasound guidance and blood attenuation correction

    NASA Astrophysics Data System (ADS)

    Dixon, Adam J.; Hossack, John A.

    2013-05-01

    Intravascular near-infrared fluorescence (NIRF) imaging offers a new approach for characterizing atherosclerotic plaque, but random catheter positioning within the vessel lumen results in variable light attenuation and can yield inaccurate measurements. We hypothesized that NIRF measurements could be corrected for variable light attenuation through blood by tracking the location of the NIRF catheter with intravascular ultrasound (IVUS). In this study, a combined NIRF-IVUS catheter was designed to acquire coregistered NIRF and IVUS data, an automated image processing algorithm was developed to measure catheter-to-vessel wall distances, and depth-dependent attenuation of the fluorescent signal was corrected by an analytical light propagation model. Performance of the catheter sensing distance correction method was evaluated in coronary artery phantoms and ex vivo arteries. The correction method produced NIRF estimates of fluorophore concentrations, in coronary artery phantoms, with an average root mean square error of 17.5%. In addition, the correction method resulted in a statistically significant improvement in correlation between spatially resolved NIRF measurements and known fluorophore spatial distributions in ex vivo arteries (from r=0.24 to 0.69, p<0.01, n=6). This work demonstrates that catheter-to-vessel wall distances, measured from IVUS images, can be employed to compensate for inaccuracies caused by variable intravascular NIRF sensing distances.

  13. High-frequency array studies of long-range Lg propagation and the causes of Lg blockage and attenuation in the Eurasian continental craton. Volume 2. Final report, 29 Sep 89-30 Jan 91

    SciTech Connect

    Baumgardt, D.R.

    1991-03-21

    An investigation was conducted of the nature of Lg propagation from the Soviet test site at Novaya Zemlya as recorded by array sensors to the south, including the new regional arrays ARCESS and NORESS, and the teleseismic Graefenburg array, located near the recently installed GERESS regional array. This study is important because of the recently announced intention of the Soviet Union to shift their underground nuclear testing activities from the test site near Semipalatinsk to Novaya Zemlya. A second study follows up earlier ones of long range Lg propagation from nuclear explosions in the continental platform and shield regions of the USSR; the present study gives geological interpretations of the efficiency of Lg propagation. The overall conclusion of these studies is that heterogeneity in the upper earth crust, sometimes referred to as the granitic layer, seems to be the primary factor in blockage of Lg. Whenever a large part of the granitic layer is replaced in a confined region as in a basin, by lower velocity sediments, such that there is a large velocity contrast between the basin sediments and the surrounding granitic rocks, Lg waves appear to be trapped in the basin and are attenuated by repeated reverberations in the basin. As a result, Lg waves are delayed, diverted, scattered, and blocked, such that their recorded amplitudes are much reduced compared with what is expected from anelastic attenuation. Effects of Lg blockages need to be taken into account whenever Lg amplitudes are used for yield estimation and event identification.

  14. RADIO FREQUENCY ATTENUATOR

    DOEpatents

    Giordano, S.

    1963-11-12

    A high peak power level r-f attenuator that is readily and easily insertable along a coaxial cable having an inner conductor and an outer annular conductor without breaking the ends thereof is presented. Spaced first and second flares in the outer conductor face each other with a slidable cylindrical outer conductor portion therebetween. Dielectric means, such as water, contact the cable between the flares to attenuate the radio-frequency energy received thereby. The cylindrical outer conductor portion is slidable to adjust the voltage standing wave ratio to a low level, and one of the flares is slidable to adjust the attenuation level. An integral dielectric container is also provided. (AFC)

  15. Landing gear noise attenuation

    NASA Technical Reports Server (NTRS)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  16. Attenuator And Conditioner

    DOEpatents

    Anderson, Gene R.; Armendariz, Marcelino G.; Carson, Richard F.; Bryan, Robert P.; Duckett, III, Edwin B.; Kemme, Shanalyn Adair; McCormick, Frederick B.; Peterson, David W.

    2006-04-04

    An apparatus and method of attenuating and/or conditioning optical energy for an optical transmitter, receiver or transceiver module is disclosed. An apparatus for attenuating the optical output of an optoelectronic connector including: a mounting surface; an array of optoelectronic devices having at least a first end; an array of optical elements having at least a first end; the first end of the array of optical elements optically aligned with the first end of the array of optoelectronic devices; an optical path extending from the first end of the array of optoelectronic devices and ending at a second end of the array of optical elements; and an attenuator in the optical path for attenuating the optical energy emitted from the array of optoelectronic devices. Alternatively, a conditioner may be adapted in the optical path for conditioning the optical energy emitted from the array of optoelectronic devices.

  17. Comparative molecular docking analysis of cytoplasmic dynein light chain DYNLL1 with pilin to explore the molecular mechanism of pathogenesis caused by Pseudomonas aeruginosa PAO.

    PubMed

    Kausar, Samina; Asif, Muhammad; Bibi, Nousheen; Rashid, Sajid

    2013-01-01

    Cytoplasmic dynein light chain 1 (DYNLL1) is a component of large protein complex, which is implicated in cargo transport processes, and is known to interact with many cellular and viral proteins through its short consensus motif (K/R)XTQT. Still, it remains to be explored that bacterial proteins also exhibit similar recognition sequences to make them vulnerable to host defense mechanism. We employed multiple docking protocols including AUTODOCK, PatchDock, ZDOCK, DOCK/PIERR and CLUSPRO to explore the DYNLL1 and Pilin interaction followed by molecular dynamics simulation assays. Subsequent structural comparison of the predicted binding site for DYNLL1-Pilin complex against the experimentally verified DYNLL1 binding partners was performed to cross check the residual contributions and to determine the binding mode. On the basis of in silico analysis, here we describe a novel interaction of DYNLL1 and receptor binding domain of Pilin (the main protein constituent of bacterial type IV Pili) of gram negative bacteria Pseudomonas aeruginosa (PAO), which is the third most common nosocomial pathogen associated with the life-threatening infections. Evidently, our results underscore that Pilin specific motif (KSTQD) exhibits a close structural similarity to that of Vaccinia virus polymerase, P protein Rabies and P protein Mokola viruses. We speculate that binding of DYNLL1 to Pilin may trigger an uncontrolled inflammatory response of the host immune system during P. aeruginosa chronic infections thereby opening a new pioneering area to investigate the role of DYNLL1 in gram negative bacterial infections other than viral infections. Moreover, by manifesting a strict correspondence between sequence and function, our study anticipates a novel drug target site to control the complications caused by P. aeruginosa infections.

  18. The acclimation of Tilia cordata stomatal opening in response to light, and stomatal anatomy to vegetational shade and its components.

    PubMed

    Aasamaa, Krõõt; Aphalo, Pedro José

    2016-09-26

    Stomatal anatomical traits and rapid responses to several components of visible light were measured in Tilia cordata Mill. seedlings grown in an open, fully sunlit field (C-set), or under different kinds of shade. The main questions were: (i) stomatal responses to which visible light spectrum regions are modified by growth-environment shade and (ii) which separate component of vegetational shade is most effective in eliciting the acclimation effects of the full vegetational shade. We found that stomatal opening in response to red or green light did not differ between the plants grown in the different environments. Stomatal response to blue light was increased (in comparison with that of C-set) in the leaves grown in full vegetational shade (IABW-set), in attenuated UVAB irradiance (AB-set) or in decreased light intensity (neutral shade) plus attenuated UVAB irradiance (IAB-set). In all sets, the addition of green light-two or four times stronger-into induction light barely changed the rate of the blue-light-stimulated stomatal opening. In the AB-set, stomatal response to blue light equalled the strong IABW-set response. In attenuated UVB-grown leaves, stomatal response fell midway between IABW- and C-set results. Blue light response by neutral shade-grown leaves did not differ from that of the C-set, and the response by the IAB-set did not differ from that of the AB-set. Stomatal size was not modified by growth environments. Stomatal density and index were remarkably decreased only in the IABW- and IAB-sets. It was concluded that differences in white light responses between T. cordata leaves grown in different light environments are caused only by their different blue light response. Differences in stomatal sensitivity are not dependent on altered stomatal anatomy. Attenuated UVAB irradiance is the most efficient component of vegetational shade in stimulating acclimation of stomata, whereas decreased light intensity plays a minor role.

  19. The Self Attenuation Correction for Holdup Measurements, a Historical Perspective

    SciTech Connect

    Oberer, R. B.; Gunn, C. A.; Chiang, L. G.

    2006-07-11

    Self attenuation has historically caused both conceptual as well as measurement problems. The purpose of this paper is to eliminate some of the historical confusion by reviewing the mathematical basis and by comparing several methods of correcting for self attenuation focusing on transmission as a central concept.

  20. Chronic restraint stress causes anxiety- and depression-like behaviors, downregulates glucocorticoid receptor expression, and attenuates glutamate release induced by brain-derived neurotrophic factor in the prefrontal cortex.

    PubMed

    Chiba, Shuichi; Numakawa, Tadahiro; Ninomiya, Midori; Richards, Misty C; Wakabayashi, Chisato; Kunugi, Hiroshi

    2012-10-01

    Stress and the resulting increase in glucocorticoid levels have been implicated in the pathophysiology of depressive disorders. We investigated the effects of chronic restraint stress (CRS: 6 hours × 28 days) on anxiety- and depression-like behaviors in rats and on the possible changes in glucocorticoid receptor (GR) expression as well as brain-derived neurotrophic factor (BDNF)-dependent neural function in the prefrontal cortex (PFC). We observed significant reductions in body weight gain, food intake and sucrose preference from 1 week after the onset of CRS. In the 5th week of CRS, we conducted open-field (OFT), elevated plus-maze (EPM) and forced swim tests (FST). We observed a decrease in the number of entries into open arms during the EPM (anxiety-like behavior) and increased immobility during the FST (depression-like behavior). When the PFC was removed after CRS and subject to western blot analysis, the GR expression reduced compared with control, while the levels of BDNF and its receptors remained unchanged. Basal glutamate concentrations in PFC acute slice which were measured by high performance liquid chromatography were not influenced by CRS. However, BDNF-induced glutamate release was attenuated after CRS. These results suggest that reduced GR expression and altered BDNF function may be involved in chronic stress-induced anxiety--and depression-like behaviors.

  1. Seismic attenuation in Florida

    SciTech Connect

    Bellini, J.J.; Bartolini, T.J.; Lord, K.M.; Smith, D.L. . Dept. of Geology)

    1993-03-01

    Seismic signals recorded by the expanded distribution of earthquake seismograph stations throughout Florida and data from a comprehensive review of record archives from stations GAI contribute to an initial seismic attenuation model for the Florida Plateau. Based on calculations of surface particle velocity, a pattern of attenuation exists that appears to deviate from that established for the remainder of the southeastern US. Most values suggest greater seismic attenuation within the Florida Plateau. However, a separate pattern may exist for those signals arising from the Gulf of Mexico. These results have important implications for seismic hazard assessments in Florida and may be indicative of the unique lithospheric identity of the Florida basement as an exotic terrane.

  2. Radiofrequency attenuator and method

    DOEpatents

    Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Agrawal, Anoop; Hall, Simon B.

    2009-11-10

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3 C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  3. Radiofrequency attenuator and method

    DOEpatents

    Warner, Benjamin P.; McCleskey, T. Mark; Burrell, Anthony K.; Agrawal, Anoop; Hall, Simon B.

    2009-01-20

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  4. LCLS XTOD Attenuator System System Concept Report

    SciTech Connect

    Kishiyama, K; Roeben, M; Trent, J; Ryutov, D; Shen, S

    2006-04-12

    The attenuator system for the Linac Coherent Light Source (LCLS) X-ray Transport, Optics and Diagnostics (XTOD) system has been configured and analyzed by the Lawrence Livermore National Laboratory's New Technologies Engineering Division (NTED) as requested by the SLAC/LCLS program. The system layout, performance analyses and selection of the vacuum components are presented in this System Conceptual Review (SCR) report. Also included are the plans for prototype, procurement, mechanical integration, and the cost estimates.

  5. Prediction of L-band signal attenuation in forests using 3D vegetation structure from airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Liu, Pang-Wei; Lee, Heezin; Judge, Jasmeet; Wright, William C.; Clint Slatton, K.

    2011-09-01

    In this study, we propose a novel method to predict microwave attenuation in forested areas by using airborne Light Detection and Ranging (LiDAR). While propagating through a vegetative medium, microwave signals suffer from reflection, absorption, and scattering within vegetation, which cause signal attenuation and, consequently, deteriorate signal reception and information interpretation. A Fresnel zone enveloping the radio frequency line-of-sight is applied to segment vegetation structure occluding signal propagation. Return parameters and the spatial distribution of vegetation from the airborne LiDAR inside Fresnel zones are used to weight the laser points to estimate directional vegetation structure. A Directional Vegetation Density (DVD) model is developed through regression that links the vegetation structure to the signal attenuation at the L-band using GPS observations in a mixed forest in North Central Florida. The DVD model is compared with currently-used empirical models and obtained better R2 values of 0.54 than the slab-based models. Finally, the model is evaluated by comparing with GPS observations of signal attenuation. An overall root mean square error of 3.51 dB and a maximum absolute error of 9.38 dB are found. Sophisticated classification algorithms and full-waveform LiDAR systems may significantly improve the estimation of signal attenuation.

  6. Loss of Melanopsin Photoreception and Antagonism of the Histamine H3 Receptor by Ciproxifan Inhibit Light-Induced Sleep in Mice

    PubMed Central

    Muindi, Fanuel; Colas, Damien; Ikeme, Jesse; Ruby, Norman F.; Heller, H. Craig

    2015-01-01

    Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose dependent as a function of light flash number. We found that exposure to 60 flashes of light occurring once every 60 seconds for 1-h (120-ms of total light over an hour) induced a similar amount of sleep as a continuous bright light pulse. Secondly, the induction of sleep by millisecond light flashes was attenuated in the absence of melanopsin when animals were presented with flashes occurring every 60 seconds over a 3-h period beginning at ZT13. Lastly, the acute administration of a histamine H3 autoreceptor antagonist, ciproxifan, blocked the induction of sleep by a 1-h continuous light pulse during the dark period. Ciproxifan caused a decrease in NREMS delta power and an increase in theta activity during both sleep and wake periods respectively. The data suggest that some form of temporal integration occurs in response to millisecond light flashes, and that this process requires melanopsin photoreception. Furthermore, the pharmacological data suggest that the increase of histaminergic neurotransmission is sufficient to attenuate the light-induced sleep response during the dark period. PMID:26083020

  7. Loss of Melanopsin Photoreception and Antagonism of the Histamine H3 Receptor by Ciproxifan Inhibit Light-Induced Sleep in Mice.

    PubMed

    Muindi, Fanuel; Colas, Damien; Ikeme, Jesse; Ruby, Norman F; Heller, H Craig

    2015-01-01

    Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose dependent as a function of light flash number. We found that exposure to 60 flashes of light occurring once every 60 seconds for 1-h (120-ms of total light over an hour) induced a similar amount of sleep as a continuous bright light pulse. Secondly, the induction of sleep by millisecond light flashes was attenuated in the absence of melanopsin when animals were presented with flashes occurring every 60 seconds over a 3-h period beginning at ZT13. Lastly, the acute administration of a histamine H3 autoreceptor antagonist, ciproxifan, blocked the induction of sleep by a 1-h continuous light pulse during the dark period. Ciproxifan caused a decrease in NREMS delta power and an increase in theta activity during both sleep and wake periods respectively. The data suggest that some form of temporal integration occurs in response to millisecond light flashes, and that this process requires melanopsin photoreception. Furthermore, the pharmacological data suggest that the increase of histaminergic neurotransmission is sufficient to attenuate the light-induced sleep response during the dark period.

  8. Tritium Attenuation by Distillation

    SciTech Connect

    Wittman, N.E.

    2001-07-31

    The objective of this study was to determine how a 100 Area distillation system could be used to reduce to a satisfactory low value the tritium content of the dilute moderator produced in the 100 Area stills, and whether such a tritium attenuator would have sufficient capacity to process all this material before it is sent to the 400 Area for reprocessing.

  9. Exercise attenuates the increase in plasma monounsaturated fatty acids and high-density lipoprotein cholesterol but not high-density lipoprotein 2b cholesterol caused by high-oleic ground beef in women.

    PubMed

    Gilmore, L Anne; Crouse, Stephen F; Carbuhn, Aaron; Klooster, Jennifer; Calles, José Antonio Elias; Meade, Thomas; Smith, Stephen B

    2013-12-01

    We hypothesized that dietary monounsaturated fatty acids (MUFA) and exercise increase high-density lipoprotein cholesterol (HDL-C) by independent mechanisms, so there would be additive effects between a single, intensive session of exercise and high-MUFA ground beef on HDL-C and blood risk factors for cardiovascular disease. Seventeen postmenopausal women completed a 2-way crossover design in which they consumed five 114-g ground beef patties per week for two 6-week periods separated by a 4-week washout (habitual diet) period. The ground beef patties contained 21% total fat with either 9.97 (low-MUFA) or 12.72 (high-MUFA) g total MUFA. Blood was taken at entry, at the end of each 6-week diet period, after the 4-week washout period, and 24 hours after aerobic exercise sessions (75% VO₂peak, 2.07 MJ). After the ground beef intervention, the high-MUFA ground beef increased plasma palmitoleic acid and oleic acid, low-density lipoprotein (LDL) particle density, HDL-C, and HDL2b-C (all P < .05), whereas the low-MUFA ground beef increased LDL density. After the washout (habitual diet) period, the single exercise session increased serum LDL cholesterol, HDL-C, and HDL2a and decreased TAG and oleic acid. After the low-MUFA ground beef diet, exercise increased LDL size and HDL density and decreased LDL density and very low-density lipoprotein cholesterol, but had no effect on HDL-C fractions. After the high-MUFA ground beef intervention, exercise decreased palmitioleic acid, oleic acid, HDL-C, and HDL2a-C, but not HDL2b-C. Contrary to our hypothesis, the effects of exercise and a high-MUFA diet were not additive; instead, exercise attenuated the effects of the high-MUFA ground beef on HDL-C and plasma MUFAs. The differential effects of high-MUFA ground beef and exercise on HDL2a-C and HDL2b-C indicate that diet and exercise affect HDL-C by different mechanisms.

  10. Yellowstone Attenuation Tomography from Ambient Seismic Noise

    NASA Astrophysics Data System (ADS)

    Doungkaew, N.; Seats, K.; Lawrence, J. F.

    2013-12-01

    The goal of this study is to create a tomographic attenuation image for the Yellowstone region by analyzing ambient seismic noise. An attenuation image generated from ambient noise should provide more information about the structure and properties beneath Yellowstone, especially the caldera, which is known to be active. I applied the method of Lawrence & Prieto [2011] to examine lateral variations in the attenuation structure of Yellowstone. Ambient noise data were collected from broadband seismic stations located around Yellowstone National Park from 1999-2013. Noise correlation functions derived from cross correlations of the ambient noise at two stations were used to calculate a distance dependent decay (an attenuation coefficient) at each period and distance. An inversion was then performed to isolate and localize the spatial attenuation coefficients within the study area. I observe high amplitude decay of the ambient noise at the Yellowstone caldera, most likely due to elevated temperature and crustal melts caused by volcanism, geothermal heat flow, and hydrothermal activity such as geysers.

  11. UV light source adaptive sensing technology for flue gas measurement

    NASA Astrophysics Data System (ADS)

    Sun, Changku; Zhang, Chi; Sun, Bo; Liu, Bin; Wang, Peng

    2010-11-01

    The UV absorption spectrometry technique DOAS (Differential Optical Absorption Spectroscopy) has been widely used in continuous monitoring of flue gas, and has achieved good results. DOAS method is based on the basic law of light absorption--Lambert-Beer law. SO2, NOX are the principal component of the flue gas. These components are considered by DOAS method at the same time. And certain mathematical methods are used for concentrations measuring. The Continuous Emission Monitoring System (CEMS) based on the principle of DOAS mainly has two probe-styles present: in-situ probe-style and extractive probe-style. For the in-situ probe-style CEMS based on DOAS method, prolonged use for the UV light source, contaminated lens caused by floating oil and complex environment of the flue will all bring attenuation of the spectral intensity, it will affect the accuracy of measurement. In this article, an in-situ continuous monitoring system based on DOAS method is described, and a component adaptive sensing technology is proposed. By using this adaptive sensing technology, CEMS can adjust the integral time of the spectrometer according to the non-measuring attenuation of the light source intensity and automatically compensate the loss of spectral intensity. Under the laboratory conditions, the experiments for SO2, NO standard gas measurement using adaptive sensing technology is made. Many different levels of light intensity attenuation are considered in the experiments. The results show that the adaptive sensing technology can well compensate the non-measuring loss of spectral intensity. In the field measurement, this technology can well reduce the measurement error brought by attenuation of light intensity, compared with the handheld gas analyzer, the average error of concentration measurement is less than 2% FS(Full Scale).

  12. Spectral anomalies of the light-induced drift effect caused by the velocity dependence of the collision broadening and shift of the absorption line

    NASA Astrophysics Data System (ADS)

    Parkhomenko, A. I.; Shalagin, Anatolii M.

    2013-02-01

    We have theoretically investigated the spectral features of the light-induced drift (LID) effect, arising due to the dependence of the collision broadening γ and shift Δ of the absorption line on the velocity of resonance particles, ν. It is shown that under certain conditions, account of this dependence can radically change the spectral shape of the LID signal, up to the appearance of additional zeros in the dependence of the drift velocity on the radiation frequency.

  13. Spectral anomalies of the light-induced drift effect caused by the velocity dependence of the collision broadening and shift of the absorption line

    SciTech Connect

    Parkhomenko, A I; Shalagin, Anatolii M

    2013-02-28

    We have theoretically investigated the spectral features of the light-induced drift (LID) effect, arising due to the dependence of the collision broadening {gamma} and shift {Delta} of the absorption line on the velocity of resonance particles, {nu}. It is shown that under certain conditions, account of this dependence can radically change the spectral shape of the LID signal, up to the appearance of additional zeros in the dependence of the drift velocity on the radiation frequency. (nonlinear optical phenomena)

  14. Pulse transducer with artifact signal attenuator. [heart rate sensors

    NASA Technical Reports Server (NTRS)

    Cash, W. H., Jr.; Polhemus, J. T. (Inventor)

    1980-01-01

    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages.

  15. Control algorithms for dynamic attenuators

    SciTech Connect

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-06-15

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  16. Spectral anomalies of the effect of light-induced drift of caesium atoms caused by the velocity dependence of transport collision frequencies

    SciTech Connect

    Parkhomenko, A I; Shalagin, A M

    2014-10-31

    The spectral features of the light-induced drift (LID) velocity of caesium atoms in inert buffer gases are studied theoretically. A strong temperature dependence of the spectral LID line shape of Cs atoms in Ar or Kr atmosphere in the vicinity of T ∼ 1000 K is predicted. It is shown that the anomalous LID of Cs atoms in binary buffer mixtures of two different inert gases can be observed at virtually any (including ambient) temperature, depending on the content of the components in these mixtures. The results obtained make it possible to precisely test the interatomic interaction potentials in the experiments on the anomalous LID. (quantum optics)

  17. Spectral anomalies of the effect of light-induced drift of caesium atoms caused by the velocity dependence of transport collision frequencies

    NASA Astrophysics Data System (ADS)

    Parkhomenko, A. I.; Shalagin, A. M.

    2014-10-01

    The spectral features of the light-induced drift (LID) velocity of caesium atoms in inert buffer gases are studied theoretically. A strong temperature dependence of the spectral LID line shape of Cs atoms in Ar or Kr atmosphere in the vicinity of T ~ 1000 K is predicted. It is shown that the anomalous LID of Cs atoms in binary buffer mixtures of two different inert gases can be observed at virtually any (including ambient) temperature, depending on the content of the components in these mixtures. The results obtained make it possible to precisely test the interatomic interaction potentials in the experiments on the anomalous LID.

  18. Ultrasonic attenuation in pearlitic steel.

    PubMed

    Du, Hualong; Turner, Joseph A

    2014-03-01

    Expressions for the attenuation coefficients of longitudinal and transverse ultrasonic waves are developed for steel with pearlitic microstructure. This type of lamellar duplex microstructure influences attenuation because of the lamellar spacing. In addition, longitudinal attenuation measurements were conducted using an unfocused transducer with 10 MHz central frequency on the cross section of a quenched railroad wheel sample. The dependence of longitudinal attenuation on the pearlite microstructure is observed from the changes of longitudinal attenuation from the quenched tread surface to deeper locations. The results show that the attenuation value is lowest and relatively constant within the quench depth, then increases linearly. The experimental results demonstrate a reasonable agreement with results from the theoretical model. Ultrasonic attenuation provides an important non-destructive method to evaluate duplex microstructure within grains which can be implemented for quality control in conjunction with other manufacturing processes.

  19. Experimental evidence of oxidative stress in patients with l-2-hydroxyglutaric aciduria and that l-carnitine attenuates in vitro DNA damage caused by d-2-hydroxyglutaric and l-2-hydroxyglutaric acids.

    PubMed

    Rodrigues, Daiane Grigolo Bardemaker; de Moura Coelho, Daniella; Sitta, Ângela; Jacques, Carlos Eduardo Diaz; Hauschild, Tatiane; Manfredini, Vanusa; Bakkali, Abdellatif; Struys, Eduard A; Jakobs, Cornelis; Wajner, Moacir; Vargas, Carmen Regla

    2017-04-07

    d-2-hydroxyglutaric (D-2-HGA) and l-2-hydroxyglutaric (L-2-HGA) acidurias are rare neurometabolic disorders biochemically characterized by increased levels of d-2-hydroxyglutaric acid (D-2-HG) and l-2-hydroxyglutaric acid (L-2-HG) respectively, in biological fluids and tissues. These diseases are caused by mutations in the specific enzymes involved in the metabolic pathways of these organic acids. In the present work, we first investigated whether D-2-HG and L-2-HGA could provoke DNA oxidative damage in blood leukocytes and whether l-carnitine (LC) could prevent the in vitro DNA damage induced by these organic acids. It was verified that 50μM of D-2-HG and 30μM of L-2-HG significantly induced DNA damage that was prevented by 30 and 150μM of LC. We also evaluated oxidative stress parameters in urine of L-2-HGA patients and observed a significant increase of oxidized guanine species and di-tyrosine, biomarkers of oxidative DNA and protein damage, respectively. In contrast, no significant changes of urinary isoprostanes and reactive nitrogen species levels were observed in these patients. Taken together, our data indicate the involvement of oxidative damage, especially on DNA, in patients affected by these diseases and the protective effect of LC.

  20. Levofloxacin-Ceftriaxone Combination Attenuates Lung Inflammation in a Mouse Model of Bacteremic Pneumonia Caused by Multidrug-Resistant Streptococcus pneumoniae via Inhibition of Cytolytic Activities of Pneumolysin and Autolysin

    PubMed Central

    Majhi, Arnab; Adhikary, Rana; Bhattacharyya, Aritra; Mahanti, Sayantika

    2014-01-01

    In this study, our objective was to determine whether a synergistic antimicrobial combination in vitro would be beneficial in the downregulation of pneumococcal virulence genes and whether the associated inflammation of the lung tissue induced by multidrug-resistant Streptococcus pneumoniae infection in vivo needs to be elucidated in order to consider this mode of therapy in case of severe pneumococcal infection. We investigated in vivo changes in the expression of these virulence determinants using an efficacious combination determined in previous studies. BALB/c mice were infected with 106 CFU of bacteria. Intravenous levofloxacin at 150 mg/kg and/or ceftriaxone at 50 mg/kg were initiated 18 h postinfection; the animals were sacrificed 0 to 24 h after the initiation of treatment. The levels of cytokines, chemokines, and C-reactive protein (CRP) in the serum and lungs, along with the levels of myeloperoxidase and nitric oxide the inflammatory cell count in bronchoalveolar lavage fluid (BALF), changes in pneumolysin and autolysin gene expression and COX-2 and inducible nitric oxide synthase (iNOS) protein expression in the lungs were estimated. Combination therapy downregulated inflammation and promoted bacterial clearance. Pneumolysin and autolysin expression was downregulated, with a concomitant decrease in the expression of COX-2 and iNOS in lung tissue. Thus, the combination of levofloxacin and ceftriaxone can be considered for therapeutic use even in cases of pneumonia caused by drug-resistant isolates. PMID:24957840

  1. Levofloxacin-ceftriaxone combination attenuates lung inflammation in a mouse model of bacteremic pneumonia caused by multidrug-resistant Streptococcus pneumoniae via inhibition of cytolytic activities of pneumolysin and autolysin.

    PubMed

    Majhi, Arnab; Adhikary, Rana; Bhattacharyya, Aritra; Mahanti, Sayantika; Bishayi, Biswadev

    2014-09-01

    In this study, our objective was to determine whether a synergistic antimicrobial combination in vitro would be beneficial in the downregulation of pneumococcal virulence genes and whether the associated inflammation of the lung tissue induced by multidrug-resistant Streptococcus pneumoniae infection in vivo needs to be elucidated in order to consider this mode of therapy in case of severe pneumococcal infection. We investigated in vivo changes in the expression of these virulence determinants using an efficacious combination determined in previous studies. BALB/c mice were infected with 10(6) CFU of bacteria. Intravenous levofloxacin at 150 mg/kg and/or ceftriaxone at 50 mg/kg were initiated 18 h postinfection; the animals were sacrificed 0 to 24 h after the initiation of treatment. The levels of cytokines, chemokines, and C-reactive protein (CRP) in the serum and lungs, along with the levels of myeloperoxidase and nitric oxide the inflammatory cell count in bronchoalveolar lavage fluid (BALF), changes in pneumolysin and autolysin gene expression and COX-2 and inducible nitric oxide synthase (iNOS) protein expression in the lungs were estimated. Combination therapy downregulated inflammation and promoted bacterial clearance. Pneumolysin and autolysin expression was downregulated, with a concomitant decrease in the expression of COX-2 and iNOS in lung tissue. Thus, the combination of levofloxacin and ceftriaxone can be considered for therapeutic use even in cases of pneumonia caused by drug-resistant isolates.

  2. Oscillations of absorption of a probe picosecond light pulse caused by its interaction with stimulated picosecond emission of GaAs

    SciTech Connect

    Ageeva, N. N.; Bronevoi, I. L. Zabegaev, D. N.; Krivonosov, A. N.

    2015-04-15

    The self-modulation of absorption of a picosecond light pulse was observed earlier [1] in a thin (∼1-μm thick) GaAs layer pumped by a high-power picosecond pulse. Analysis of the characteristics of this self-modulation predicted [5] that the dependences of the probe pulse absorption on the pump pulse energy and picosecond delay between pump and probe pulses should be self-modulated by oscillations. Such self-modulation was experimentally observed in this work. Under certain conditions, absorption oscillations proved to be a function of part of the energy of picosecond stimulated emission of GaAs lying above a certain threshold in the region where the emission front overlapped the probe pulse front. Absorption oscillations are similar to self-modulation of the GaAs emission characteristics observed earlier [4]. This suggests that the self-modulation of absorption and emission is determined by the same type of interaction of light pulses in the active medium, the physical mechanism of which has yet to be determined.

  3. A novel class of sticky peel and light green mutations causes cuticle deficiency in leaves and fruits of tomato (Solanum lycopersicum).

    PubMed

    Kimbara, Junji; Yoshida, Miho; Ito, Hirotaka; Hosoi, Katsutoshi; Kusano, Miyako; Kobayashi, Makoto; Ariizumi, Tohru; Asamizu, Erika; Ezura, Hiroshi

    2012-11-01

    The plant cuticle consists of aliphatic wax and cutin, and covers all the aerial tissues, conferring resistance to both biotic and abiotic stresses. In this study, we performed phenotypic characterizations of tomato mutants having both sticky peel (pe) and light green (lg) mutations. Our genetic analysis showed that these two mutations are tightly linked and behave like a monogenic recessive mutation. The double mutant (pe lg) produced glossy soft fruits with light green leaves, most likely due to defects in cuticle formation. Cytological analysis revealed that the thickness of the fruit cuticle layer was dramatically reduced in the pe lg mutant. The epidermal cells of the leaves were also deformed in the pe lg mutant, suggesting that leaf cuticle formation was also disrupted in the mutant. Consistent with this, transmission electron microscopic analysis showed that the electron density of the cuticle layer of the adaxial surface of the leaf was reduced in the pe lg mutant compared to WT, suggesting that there are changes in cuticle structure and/or composition in the pe lg mutant. Both physiological analysis to measure the rate of transpiration, and staining of the fruits and leaves with toluidine blue, revealed that water permeability was enhanced in the pe lg mutant, consistent with the reduced thickness of its cuticle layer. Taken together the preliminary analyses of the cuticle components, the PE LG is most likely involved in proper cuticle formation.

  4. Forced oscillation measurements of seismic attenuation in fluid saturated sandstone

    NASA Astrophysics Data System (ADS)

    Subramaniyan, Shankar; Quintal, Beatriz; Saenger, Erik H.

    2017-02-01

    Adopting the method of forced oscillation, attenuation was studied in Fontainebleau sandstone (porosity 10%, permeability 10 mD) at seismic frequencies (1-100 Hz). Confining pressures of 5, 10, and 15 MPa were chosen to simulate reservoir conditions. First, the strain effect on attenuation was investigated in the dry sample for 11 different strains across the range 1 × 10-6-8 × 10-6, at the confining pressure of 5 MPa. The comparison showed that a strain of at least 5 × 10-6 is necessary to obtain a good signal to noise ratio. These results also indicate that nonlinear effects are absent for strains up to 8 × 10-6. For all the confining pressures, attenuation in the dry rock was low, while partial (90%) and full (100%) saturation with water yielded a higher magnitude and frequency dependence of attenuation. The observed high and frequency dependent attenuation was interpreted as being caused by squirt flow.

  5. Clinical Presentation of Tubulointerstitial Nephritis Caused by Amyloid Light-chain Amyloidosis in a Patient with Sjögren's Syndrome

    PubMed Central

    Inoue, Reiko; Fujigaki, Yoshihide; Kobayashi, Kana; Tamura, Yoshifuru; Ota, Tatsuru; Shibata, Shigeru; Ishida, Tsuyoshi; Kondo, Fukuo; Yamaguchi, Yutaka; Uchida, Shunya

    2017-01-01

    We report a 70-year-old woman with Sjögren's syndrome who had severe renal dysfunction with mild proteinuria and elevated urinary low-molecular-weight proteins. Based on these clinical presentations, interstitial nephritis due to Sjögren's syndrome was strongly suspected. Unexpectedly, renal pathology revealed amyloid light-chain (AL) lambda-type depositions predominantly in the vasculatures with severe tubulointerstitial damage. Concentrated urine immunofixation was positive for Bence Jones lambda-type monoclonal proteins. Given the involvement in other organs, systemic AL amyloidosis was diagnosed. The patient underwent chemotherapy, but hemodialysis was ultimately instituted. It should be remembered that renal amyloidosis occurs as a clinical presentation of interstitial nephritis. PMID:28202864

  6. Light-induced isomerization causes an increase in the chromophore tilt in the M intermediate of bacteriorhodopsin: a neutron diffraction study.

    PubMed Central

    Hauss, T; Büldt, G; Heyn, M P; Dencher, N A

    1994-01-01

    Bacteriorhodopsin (BR) was regenerated with two selectively deuterated retinals, one with 11 deuterons in the beta-ionone ring (D11) and the other with 5 deuterons (D5) at the end of the polyene chain closest to the Schiff base at carbon atoms C-14, C-15, and C-20. Both label positions (centers of deuteration) were obtained from difference Fourier maps of projections onto the plane of the membrane by neutron diffraction at 90 K, both in the light-adapted ground-state BR568 and in the photocycle intermediate M412. To retard the decay of M412, purple membrane films were soaked in 0.1 M or 1 M guanidine hydrochloride at pH 9.6. M412 was produced by illuminating oriented membrane films at physiological temperature (278 K), followed by rapid cooling to 90 K in the absence of light. The results show that in the projected structure the ring position is unaltered during the transition from BR568 to M412, whereas the position of the D5 label shifts by 1.4 +/- 0.9 A toward the ring. The shortened interlabel distance in the projected structure for the M412 state implies that as a result of the all-trans/13-cis isomerization, the C-5 to C-13 part of the polyene chain tilts out of the plane of the membrane toward the cytoplasm by about 11 degrees +/- 6 degrees. Pairwise comparison of data sets with the same retinal for the two photocycle states M412 and BR568 leads to four difference-density maps for the protein, which are in agreement with previous work. They show changes in the protein density near helices G and F. PMID:7991546

  7. Characterization of available light for seagrass and patch reef productivity in Sugarloaf Key, Lower Florida Keys

    USGS Publications Warehouse

    Toro-Farmer, Gerardo; Muller-Karger, Frank E.; Vega-Rodriguez, Maria; Melo, Nelson; Yates, Kimberly K.; Johns, Elizabeth; Cerdeira-Estrada, Sergio; Herwitz, Stan R.

    2016-01-01

    Light availability is an important factor driving primary productivity in benthic ecosystems, but in situ and remote sensing measurements of light quality are limited for coral reefs and seagrass beds. We evaluated the productivity responses of a patch reef and a seagrass site in the Lower Florida Keys to ambient light availability and spectral quality. In situ optical properties were characterized utilizing moored and water column bio-optical and hydrographic measurements. Net ecosystem productivity (NEP) was also estimated for these study sites using benthic productivity chambers. Our results show higher spectral light attenuation and absorption, and lower irradiance during low tide in the patch reef, tracking the influx of materials from shallower coastal areas. In contrast, the intrusion of clearer surface Atlantic Ocean water caused lower values of spectral attenuation and absorption, and higher irradiance in the patch reef during high tide. Storms during the studied period, with winds >10 m·s−1, caused higher spectral attenuation values. A spatial gradient of NEP was observed, from high productivity in the shallow seagrass area, to lower productivity in deeper patch reefs. The highest daytime NEP was observed in the seagrass, with values of almost 0.4 g·O2·m−2·h−1. Productivity at the patch reef area was lower in May than during October 2012 (mean = 0.137 and 0.177 g·O2·m−2·h−1, respectively). Higher photosynthetic active radiation (PAR) levels measured above water and lower light attenuation in the red region of the visible spectrum (~666 to ~699 nm) had a positive correlation with NEP. Our results indicate that changes in light availability and quality by suspended or resuspended particles limit benthic productivity in the Florida Keys.

  8. Signature of seismic wave attenuation during fracture network formation

    NASA Astrophysics Data System (ADS)

    Barnhoorn, Auke; Zhubayev, Alimzhan; Houben, Maartje; Hardebol, Nico; Smeulders, David

    2015-04-01

    Seismic waves are significantly affected by the presence of fractures and faults. Fractures alter the arrival time of a seismic wave and the amplitude of the seismic wave. Attenuation of a seismic wave is the reduction of wave amplitude due to the presence of e.g. fractures. Attenuation of acoustic compressional P- and shear S-waves have been measured in laboratory studies on different rock types. These studies generally show a decrease in attenuation with an increase in stress. This decrease in attenuation is attributed to progressive crack closure of pre-existing cracks. The stress-dependent decrease in attenuation reported in these studies all occur within the elastic deformation field, i.e. below yield stress levels and thus no additional cracks/micro-fractures have yet been formed. At stress levels just above the yield strength the first fractures start to form. With increasing stress, fractures nucleate, grow and coalesce until a connected network of fractures has developed at which failure of the rock sample occurs. The change in attenuation during the fracturing process however has seldom been investigated. In analogy to fracture closure, where attenuation generally decreases, fracture formation should cause again an increase in attenuation. Here we report an experimental study on shales from Whitby (UK), where s-wave attenuation was measured in the laboratory during an increase in stress towards fracture formation until complete failure of the shale samples. Before yield stress conditions, as expected an increase in stress caused a gradual decrease in attenuation. At the transition from elastic to inelastic deformation behaviour, the first microfractures start to form and attenuation starts to increase again. This reversal in attenuation behaviour could potentially be used as an indicator that failure of a rock mass under stress is imminent (imminence of seismicity). The measured seismic velocities do not depict the transition from elastic to inelastic

  9. Understanding causes and effects of non-uniform light distributions on multi-junction solar cells: Procedures for estimating efficiency losses

    NASA Astrophysics Data System (ADS)

    Herrero, Rebeca; Victoria, Marta; Domínguez, César; Askins, Stephen; Antón, Ignacio; Sala, Gabriel

    2015-09-01

    This paper presents the mechanisms of efficiency losses that have to do with the non-uniformity of the irradiance over the multi-junction solar cells and different measurement techniques used to investigate them. To show the capabilities of the presented techniques, three different concentrators (that consist of an acrylic Fresnel lens, different SOEs and a lattice matched multi-junction cell) are evaluated. By employing these techniques is possible to answer some critical questions when designing concentrators as for example which degree of non-uniformity the cell can withstand, how critical the influence of series resistance is, or what kind of non-uniformity (spatial or spectral) causes more losses.

  10. Bubbles attenuate elastic waves at seismic frequencies

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Quintal, Beatriz; Chapman, Samuel; Podladchikov, Yury; Burg, Jean-Pierre

    2016-04-01

    The vertical migration of multiphase fluids in the crust can cause hazardous events such as eruptions, explosions, pollution and earthquakes. Although seismic tomography could potentially provide a detailed image of such fluid-saturated regions, the interpretation of the tomographic signals is often controversial and fails in providing a conclusive map of the subsurface saturation. Seismic tomography should be improved considering seismic wave attenuation (1/Q) and the dispersive elastic moduli which allow accounting for the energy lost by the propagating elastic wave. In particular, in saturated media a significant portion of the energy carried by the propagating wave is dissipated by the wave-induced-fluid-flow and the wave-induced-gas-exsolution-dissolution (WIGED) mechanisms. The WIGED mechanism describes how a propagating wave modifies the thermodynamic equillibrium between different fluid phases causing the exsolution and the dissolution of the gas in the liquid, which in turn causes a significant frequency dependent 1/Q and moduli dispersion. The WIGED theory was initially postulated for bubbly magmas but only recently was extended to bubbly water and experimentally demonstrated. Here we report these theory and laboratory experiments. Specifically, we present i) attenuation measurements performed by means of the Broad Band Attenuation Vessel on porous media saturated with water and different gases, and ii) numerical experiments validating the laboratory observations. Finally, we will extend the theory to fluids and to pressure-temperature conditions which are typical of phreatomagmatic and hydrocarbon domains and we will compare the propagation of seismic waves in bubble-free and bubble-bearing subsurface domains. With the present contribution we extend the knowledge about attenuation in rocks which are saturated with multiphase fluid demonstrating that the WIGED mechanism could be extremely important to image subsurface gas plumes.

  11. Methane Production Pathways in a California Rice Paddy: Isotopic Evidence for Substantial CO2 Reduction as Cause for Isotopically Light Emitted CH4 Carbon

    NASA Astrophysics Data System (ADS)

    Tyler, S. C.; McMillan, A. M.; Bearden, K.; Chidthaisong, A.; Macalady, J.

    2003-12-01

    We report measurements of δ 13C of emitted CH4 and sediment CH4 and CO2 during the 1999 rice-growing season near Maxwell, CA. Two treatments, one with rice straw incorporated from the previous season and one without rice straw were studied. The δ 13C value of emitted CH4 was consistently lighter isotopically (-67‰ to -83‰ throughout the season) in both straw incorporated and straw removed (burned) plots than in fields we have studied in Texas, Kenya, and Japan. Measured isotopic values of the production zone CH4 were compared to a two-point mixing curve representative of isotopic CH4 produced from either pure methyl-group fermentation or CO2 reduction pathways to partition the production pathways and to track seasonal changes in the production processes. Our sediment CH4 and CO2 isotope data indicate that fermentation was rarely the dominant methanogenic pathway - on the contrary CO2 reduction with H2 was more prevalent than fermentation methanogenesis throughout most of the season. The relatively isotopically light CH4 emitted by the paddy fields is also a product of oxidation and stem-transport processes which have isotopic effects of their own. These effects are discussed in context with the methanogenic isotope effects to provide a complete picture of the paddy field CH4 carbon isotope system.

  12. Ultrasonic Attenuation in Zircaloy-4

    SciTech Connect

    Gomez, M.P.; Banchik, A.D.; Lopez Pumarega, M.I.; Ruzzante, J.E.

    2005-04-09

    In this work the relationship between Zircaloy-4 grain size and ultrasonic attenuation behavior was studied for longitudinal waves in the frequency range of 10-90 MHz. The attenuation was analyzed as a function of frequency for samples with different mechanical and heat treatments having recrystallized and Widmanstatten structures with different grain size. The attenuation behavior was analyzed by different scattering models, depending on grain size, wavelength and frequency.

  13. Attenuation of Cavity Bay Noise

    DTIC Science & Technology

    2012-10-01

    amplification, known as peaking. Overall, the palliative devices based on resonant arrays have demonstrated high levels of attenuation which are...when the resonant frequency condition is met. The attenuation from a Helmholtz type resonator is achieved through frictional losses, vortex shedding...3 the λ/4 condition can be fulfilled and therefore porous mesh devices may not be able to provide a high level of attenuation . Resonant arrays

  14. The Gas Flow from the Gas Attenuator to the Beam Line

    SciTech Connect

    Ryutov, D.D.

    2010-12-03

    The gas leak from the gas attenuator to the main beam line of the Linac Coherent Light Source has been evaluated, with the effect of the Knudsen molecular beam included. It has been found that the gas leak from the gas attenuator of the present design, with nitrogen as a working gas, does not exceed 10{sup -5} torr x l/s even at the highest pressure in the main attenuation cell (20 torr).

  15. LINE-ABOVE-GROUND ATTENUATOR

    DOEpatents

    Wilds, R.B.; Ames, J.R.

    1957-09-24

    The line-above-ground attenuator provides a continuously variable microwave attenuator for a coaxial line that is capable of high attenuation and low insertion loss. The device consists of a short section of the line-above- ground plane type transmission lime, a pair of identical rectangular slabs of lossy material like polytron, whose longitudinal axes are parallel to and indentically spaced away from either side of the line, and a geared mechanism to adjust amd maintain this spaced relationship. This device permits optimum fineness and accuracy of attenuator control which heretofore has been difficult to achieve.

  16. 405 ± 5 nm light emitting diode illumination causes photodynamic inactivation of Salmonella spp. on fresh-cut papaya without deterioration.

    PubMed

    Kim, Min-Jeong; Bang, Woo Suk; Yuk, Hyun-Gyun

    2017-04-01

    This study evaluated the antibacterial effect of 405 ± 5 nm light emitting diode (LED) illumination against four Salmonella serovars on fresh-cut papaya and on fruit quality at various storage temperatures. To determine the antibacterial mechanism of LED illumination at 0.9 kJ/cm(2), oxidative damage to DNA and membrane lipids of Salmonella in phosphate-buffered saline solution was measured. The populations of Salmonella on cut fruits were significantly (P < 0.05) reduced by 0.3-1.3 log CFU/cm(2) at chilling temperatures following LED illumination for 36-48 h (1.3-1.7 kJ/cm(2)). However, at room temperature, bacterial populations increased rapidly to 6.3-7.0 log CFU/cm(2) following LED illumination for 24 h (0.9 kJ/cm(2)), which was approximately 1.0 log lower than the number of colonies on non-illuminated fruits. Levels of bacterial DNA oxidation significantly increased, whereas lipid peroxidation in bacterial membrane was not observed, suggesting that DNA oxidation contributes to photodynamic inactivation by LED illumination. LED illumination did not adversely affect the physicochemical and nutritional qualities of cut papaya, regardless of storage temperature. These results indicate that a food chiller equipped with 405 ± 5 nm LEDs can preserve fresh-cut papayas in retail stores without deterioration, minimizing the risk of salmonellosis.

  17. Bili lights

    MedlinePlus

    Phototherapy for jaundice; Bilirubin - bili lights; Neonatal care - bili lights; Newborn care - bili lights ... Phototherapy involves shining fluorescent light from the bili lights on bare skin. A specific wavelength of light can break down bilirubin into a form that ...

  18. Sn Attenuation in the Middle-East

    NASA Astrophysics Data System (ADS)

    Ku, W.; Kaviani, A.; Bao, X.; Sandvol, E. A.

    2015-12-01

    The Turkish-Iranian Plateau and Zagros Mountains, a dominant tectonic feature in the Middle-East, were formed as a result of the continental collision (between Arabian plate and Eurasia plates). In order to better understand the nature of the lithosphere mantle and origin of the measure seismic velocity anomalies we have made detailed measurements of the uppermost mantle attenuation using the high frequency regional phase Sn. In order to measure Sn attenuation. We have collected a large data set consisting of 18 years (1995-2012) of waveforms recorded by 305 permanent and temporary stations. We used a bandpass filter (0.1-0.5Hz) to identify efficient longer period Sn phases. In order to determine Sn Q we applied a Two Station Method (TSM) and Reverse Two Station Method (RTM) to eliminate the source effects. We have used the LSQR algorithm to tomographically map Sn attenuation tomography across the Middle-East. We also determined the Sn propagation efficiencies visually and tomographically map qualitatively assigned Sn propagation efficiencies across the Middle-East. The Sn Attenuation Tomography show moderately low Q values beneath the Turkish-Iranian Plateau (~250) and high Q values beneath the south Caspian sea (~400) and Arabian shield (~400). We also observe high Q values beneath the Zagros mountains (~450) that is consistent with the Arabian plate underthrusting beneath the Eurasia plate. The Sn Efficiency Tomography shows high attenuation within the Turkish-Iranian Plateau and low attenuation in the Arabian Plate and across the Caspian Sea. This is consistent with prior studies that suggest a hot and thin lithosphere beneath the Turkish-Iranian Plateau and it also suggests that intrinsic attenuation is the dominant component in Sn Q across the Turkish-Iranian Plateau. Due to the signal-to-noise criterion to select amplitudes and the efficiency criterion to select two-station and reverse-two-station paths for the inversion, the data are left-censored and the

  19. Seismic attenuation of the inner core: Viscoelastic or stratigraphic?

    USGS Publications Warehouse

    Cormier, V.F.; Xu, L.; Choy, G.L.

    1998-01-01

    Broadband velocity waveforms of PKIKP in the distance range 150??to 180??are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in measured Q-1 exceeds individual error estimates, suggesting significant variation in attenuation with path. These results are interpreted by (1) viscoelasticity, in which the relaxation spectrum has a low-frequency corner near or slightly above the frequency band of short-period body waves, and by (2) stratigraphic (scattering) attenuation, in which attenuation and pulse broadening are caused by the interference of scattered multiples in a velocity structure having rapid fluctuations along a PKIKP path. In the scattering interpretation, PKIKP attenuation is only weakly affected by the intrinsic shear attenuation measured in the free-oscillation band. Instead, its frequency dependence, path variations, and fluctuations are all explained by scattering attenuation in a heterogeneous fabric resulting from solidification texturing of intrinsically anisotropic iron. The requisite fabric may consist of either single or ordered groups of crystals with P velocity differences of at least 5% and as much as 12% between two crystallographic axes at scale lengths of 0.5 to 2 km in the direction parallel to the axis of rotation and longer in the cylindrically radial direction, perpendicular to the axis of rotation.Broadband velocity waveforms of PKIKP in the distance range 150?? to 180?? are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in the measured Q-1 exceeds individual error estimates, indicating significant variation in attenuation with path. The results are interpreted by viscoelasticity and stratigraphic (scattering) attenuation.

  20. Transformation of microbial cenoses in soils of light coniferous forests caused by cuttings and fires in the Lower Angara River basin

    NASA Astrophysics Data System (ADS)

    Bogorodskaya, A. V.; Kukavskaya, E. A.; Ivanova, G. A.

    2014-03-01

    The influence of surface fires and cutting on the quantitative and functional parameters of microbial cenoses in the soils of light coniferous forests in the Lower Angara River basin was studied. In the litters of soddy-podzolic soils under pine forests, the microbial biomass was 4080-4700 μg C/g; the basal respiration was 17.00-20.32 μg C-CO2/g/h; and the qCO2, 4.17-4.33 μg C-CO2/mg Cmic/h. In the humus-accumulative horizon, these values were 880-1160 μg C/g, 2.48-4.12 μg C-CO2/g/h, and 2.83-3.55 C-CO2/mg Cmic/h, respectively. In the litter of the one-year-old felled area, the content of microbial biomass carbon was by two times lower; in the litter of burned plots, it was by 60-70% lower than in the litter of the control area. The intensity of the microbial respiration did not change proportionally to the microbial biomass content, which resulted in an imbalance between the processes of the organic matter mineralization-immobilization towards a release of CO2 as evidenced by the increase of the qCO2 values by 2-4 times. In the five-year-old felled area, at the stage of restoring the herbaceous vegetation, a tendency towards the stabilization of the destructive microbiological processes was revealed. In the felled areas, the high number of heterotrophic microorganisms, the reduced oligotrophy of the soil organic horizons, and the more intense microbiological mineralization of the organic matter were observed. The surface fires in the felled areas and forests significantly affected the structure and the number of ecological-trophic groups of microorganisms in the litters, the humus-accumulative horizons, and in the upper mineral soil layers. The maximal structural and functional disturbance in the soil microbial complex was found in the logged areas affected by fires.

  1. Effects of garlic on cellular doubling time and DNA strand breaks caused by UV light and BPL, enhanced with catechol and TPA

    SciTech Connect

    Baturay, N.Z.; Gayle, F.; Liu, S.; Kreidinger, C.

    1995-11-01

    3T3 cell cultures were exposed to UV light and Beta-Propiolactone. Neoplastic cell transformation (TF) was demonstrated after concurrent addition of catechol, or repeated addition of TPA. Addition of garlic to all fluences/concentrations of the carcinogen/cocarcinogen/promoter groups reduced the number of transformed foci/dish by at least 40%. Since the cell cycle is prolonged following exposure to carcinogens, it is likely the cell requires a longer time to repair this damage. The doubling time (DT) was extended from 12 to 36 hrs. when cells were exposed to BPL and from 12 o 28 hrs. when cells were exposed to 3.0J/M2/sec. If an anticarcinogenic compound is also added, it is reasonable to assume that the cell cycle may be further elongated. The cell cycle, denoted by DT was lengthened from 12 to 47 hrs and from 12 to 86 hrs for BPL and UVC, respectively. The extensions occurred in a dope dependent manner. The concentrations of the cocarcinogen and promoter remained constant throughout the experiment. When strand breaks were determined at the same dose sequences, by alkaline elution, more repair was seen with garlic where the lowest and middle doses of BPL were used and almost no decrease in % DNA eluted was seen with UVC exposed cells. With catechol, there was a two-fold decrease in % DNA eluted at the lowest and middle fluences. When TPA was added, all three fluences of UVC showed more than a threefold decrease in % DNA eluted. BPS with both TPA and catechol, again showed a reduction in strand breaks only low and middle doses. Both a direct-acting alkylating agent, BPL, and a physical carcinogen, UVC, were homogeneously affected, in terms of doubling time, but not when strand break repair was examined. A separate mechanism may be responsible for repair, and the mechanism associated with combinations of physical carcinogen enhancing agents combined with some non-carcinogens may be more profoundly affected by some natural products.

  2. Suicide Risk: Amplifiers and Attenuators.

    ERIC Educational Resources Information Center

    Plutchik, Robert; Van Praag, Herman M.

    1994-01-01

    Attempts to integrate findings on correlates of suicide and violent risk in terms of a theory called a two-stage model of countervailing forces, which assumes that the strength of aggressive impulses is modified by amplifiers and attenuators. The vectorial interaction of amplifiers and attenuators creates an unstable equilibrium making prediction…

  3. AOSC multichannel electronic variable optical attenuator

    NASA Astrophysics Data System (ADS)

    Vonsovici, Adrian P.; Day, Ian E.; House, Andrew A.; Asghari, Mehdi

    2001-05-01

    Optical networks are becoming a reality as the physical layer of high-performance telecommunication networks. The deployment of wavelength-division multiplexing (WDM) technology allows the extended exploitation of installed fibers now facing an increasing traffic capacity demand. Performances of such systems can be degraded by wide variations of the optical channel power following propagation in the network. Therefore a tilt control of optical amplifiers in WDM networks and dynamic channel power regulation and equalisation in cross-connected nodes is necessary. An important tool for the system designer is the variable optical attenuator (VOA). We present the design and the realization of newly developed VOAs using the ASOC technology. This technology refers to the fabrication of integrated optics components in silicon-on-insulator (SOI) material. The device is based on the light absorption by the free-carriers that are injected in the core of a rib waveguide from a p-i-n diode. The devices incorporate horizontally and vertically tapered waveguides for minimum fiber coupling loss. The p-i-n diode for carrier injection into the active region of the rib waveguide was optimised in order to enhance the attenuation. One major advantage of the ASOC technology is the possibility of monolithic integration of many integrated optics devices on one chip. In the light of this the paper illustrates the result of characterisation of multichannel VOAs.

  4. Designing inorganic light-protective skin nanotechnology products.

    PubMed

    Popov, Alexey P; Zvyagin, Andrei V; Lademann, Juergen; Roberts, Michael S; Sanchez, Washington; Priezzhev, Alexander V; Myllylä, Risto

    2010-10-01

    In this review, we discuss the use of inorganic nanoparticles, mainly zinc oxide (ZnO) and titanium dioxide (TiO2), for sunscreen applications considering their intrinsic physical properties and the Mie theory. These properties cause, from one side, attenuation of the ultraviolet light by absorption and scattering (dependent on a particle size), which is the purpose sunscreens are designed for, and formation of free radicals (i.e., phototoxicity) during this process--from the other. Particle penetration into skin is also an important issue addressed in this review due to possible adverse effects associated with interaction between nanoparticles and skin living cells.

  5. Mapping Pn amplitude spreading and attenuation in Asia

    SciTech Connect

    Yang, Xiaoning; Phillips, William S; Stead, Richard J

    2010-12-06

    Pn travels most of its path in the mantle lid. Mapping the lateral variation of Pn amplitude attenuation sheds light on material properties and dynamics of the uppermost region of the mantle. Pn amplitude variation depends on the wavefront geometric spreading as well as material attenuation. We investigated Pn geometric spreading, which is much more complex than a traditionally assumed power-law spreading model, using both synthetic and observed amplitude data collected in Asia. We derived a new Pn spreading model based on the formulation that was proposed previously to account for the spherical shape of the Earth (Yang et. al., BSSA, 2007). New parameters derived for the spreading model provide much better correction for Pn amplitudes in terms of residual behavior. Because we used observed Pn amplitudes to construct the model, the model incorporates not only the effect of the Earth's spherical shape, but also the effect of potential upper-mantle velocity gradients in the region. Using the new spreading model, we corrected Pn amplitudes measured at 1, 2, 4 and 6 Hz and conducted attenuation tomography. The resulting Pn attenuation model correlates well with the regional geology. We see high attenuation in regions such as northern Tibetan Plateau and the western Pacific subduction zone, and low attenuation for stable blocks such as Sichuan and Tarim basins.

  6. Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses.

    PubMed

    Haga, Ken; Tsuchida-Mayama, Tomoko; Yamada, Mizuki; Sakai, Tatsuya

    2015-04-01

    Living organisms adapt to changing light environments via mechanisms that enhance photosensitivity under darkness and attenuate photosensitivity under bright light conditions. In hypocotyl phototropism, phototropin1 (phot1) blue light photoreceptors mediate both the pulse light-induced, first positive phototropism and the continuous light-induced, second positive phototropism, suggesting the existence of a mechanism that alters their photosensitivity. Here, we show that light induction of ROOT PHOTOTROPISM2 (RPT2) underlies photosensory adaptation in hypocotyl phototropism of Arabidopsis thaliana. rpt2 loss-of-function mutants exhibited increased photosensitivity to very low fluence blue light but were insensitive to low fluence blue light. Expression of RPT2 prior to phototropic stimulation in etiolated seedlings reduced photosensitivity during first positive phototropism and accelerated second positive phototropism. Our microscopy and biochemical analyses indicated that blue light irradiation causes dephosphorylation of NONPHOTOTROPIC HYPOCOTYL3 (NPH3) proteins and mediates their release from the plasma membrane. These phenomena correlate closely with the desensitization of phot1 signaling during the transition period from first positive phototropism to second positive phototropism. RPT2 modulated the phosphorylation of NPH3 and promoted reconstruction of the phot1-NPH3 complex on the plasma membrane. We conclude that photosensitivity is increased in the absence of RPT2 and that this results in the desensitization of phot1. Light-mediated induction of RPT2 then reduces the photosensitivity of phot1, which is required for second positive phototropism under bright light conditions.

  7. Thin-Layering Effect On Estimating Seismic Attenuation In Methane Hydrate-Bearing Sediments

    NASA Astrophysics Data System (ADS)

    Lee, K.; Matsushima, J.

    2012-12-01

    Seismic attenuation is one of the important parameters that provide information concerning both the detection and quantitative assessment of gas-hydrates. We estimated seismic attenuation (1/Q) from surface seismic data acquired at Nankai Trough in Japan. We adapt the Q-versus offset (QVO) method to calculate robust and continuous interval attenuations from CMP gathers. We could observe high attenuation in methane hydrate bearing sediments over the BSR region. However some negative 1/Q values are also shown. This means that the amplitude of high frequency components is increasing with depth. Such results may be due to tuning effect. Here, we carried out numerical test to see how thin-layering effect influences on seismic attenuation results. The results showed that tuning considerably influences the attenuation results, and causes the lower 1/Q values (lower attenuation) and negative 1/Q values.

  8. Resveratrol Attenuates Diabetic Nephropathy via Modulating Angiogenesis

    PubMed Central

    Zhang, Min; Zhang, Liying; Chen, Jing; Gu, Yong; Hao, Chuan-Ming

    2013-01-01

    Angiogenesis plays an important role in the pathogenesis of diabetic nephropathy (DN). In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with antiangiogenic activity in DN. In a type 1 diabetic rat model, resveratrol treatment blunted the increases of urine albumin excretion, kidney weight and creatinine clearance rate. The increases of glomerular diameter, mesangium accumulation, glomerular basement membrane thickness and renal fibrosis in diabetic rats were also reduced by resveratrol treatment. In the diabetic kidney, increased expression of vascular endothelial growth factor (VEGF), Flk-1 and angiopoietin 2, and reduced expression of Tie-2 were observed. These changes in angiogenic hormones and associated receptors were attenuated by resveratrol treatment. No changes in angiopoietin 1 expression were detected among each group of rats. Resveratrol also significantly downregulated high glucose-induced VEGF and Flk-1 expressions in cultured mouse glomerular podocytes and endothelial cells, respectively. These effects were attenuated by knocking-down silent information regulator 1 (Sirt1) expression. In contrast, upregulation of Sirt1 in cultured endothelial cells reduced Flk-1 expression. Increased permeability and cellular junction disruption of cultured endothelial cells caused by VEGF were also inhibited by resveratrol pretreatment. Taken together, the present study demonstrated that resveratrol may attenuate DN via modulating angiogenesis. PMID:24312656

  9. Practitioner perceptions of attenuated psychosis syndrome.

    PubMed

    Jacobs, Elizabeth; Kline, Emily; Schiffman, Jason

    2011-09-01

    The "Attenuated Psychosis Syndrome" (APS, sometimes referred to as the "schizophrenia prodrome") is characterized by subthreshold psychotic-like symptoms and functional decline, and is often associated with significant disability. These symptoms may cause impairment and are of further interest due to their predictive relation to schizophrenia and other psychotic disorders. These symptoms currently are not represented in the diagnostic system for mental health, and it is unclear how they are conceptualized by relevant professionals. The current study surveyed a national sample (n=303) of clinical psychologists, psychiatrists, and general practitioners regarding their clinical appraisal of APS. Practitioners were asked to respond to vignettes representing three conditions: psychosis, subthreshold psychosis (indicating 'attenuated' psychosis symptoms), and no psychotic symptoms. Practitioners' responses suggested that APS is viewed consistently with a DSM-IV-TR defined mental disorder and that most clinicians may diagnose this condition as a full threshold psychotic disorder. Findings tentatively suggest that the inclusion of an attenuated psychosis symptoms category in the forthcoming DSM-5 may be helpful in improving diagnostic reliability and facilitating best practice among community practitioners.

  10. Engineering light outcoupling in 2D materials.

    PubMed

    Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  11. Lighting: Green Light.

    ERIC Educational Resources Information Center

    Maniccia, Dorine

    2003-01-01

    Explains that by using sustainable (green) building practices, schools and universities can make their lighting systems more efficient, noting that embracing green design principles can help schools attract students. Discusses lighting-control technologies (occupancy sensing technology, daylighting technology, and scheduling based technologies),…

  12. Annoyance caused by light aircraft noise

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The correlation between objective and noise stresses and subjectively perceived disturbance from general aviation aircraft was studied at 6 Swiss airports. Noise levels calculated for these airports are given. Survey results are analyzed.

  13. Patient position alters attenuation effects in multipinhole cardiac SPECT

    SciTech Connect

    Timmins, Rachel; Ruddy, Terrence D.; Wells, R. Glenn

    2015-03-15

    Purpose: Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Methods: Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Results: Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of <1.5 for the water phantom but up to 4.2 in the anthropomorphic phantom. Changes were larger for axial than for transverse translations. These results were supported by SPS changes of up to six seen in the physical anthropomorphic phantom for axial translations. Defect width was also seen to significantly increase. The

  14. Theoretical and numerical results on effects of attenuation on correlation functions of ambient seismic noise

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Ben-Zion, Yehuda

    2013-09-01

    We study analytically and numerically effects of attenuation on cross-correlation functions of ambient noise in a 2-D model with different attenuation constants between and outside a pair of stations. The attenuation is accounted for by quality factor Q(ω) and complex phase velocity. The analytical results are derived for isotropic far-field source distribution assuming the Fresnel approximation and mild attenuation. More general situations including cases with non-isotropic source distributions are examined with numerical simulations. The results show that homogeneous attenuation in the interstation regions produces symmetric amplitude decay of the causal and anticausal parts of the noise cross-correlation function. The attenuation between the receivers and far-field sources generates symmetric exponential amplitude decay and may also cause asymmetric reduction of the causal/anticausal parts that increases with frequency. This frequency dependence can be used to distinguish asymmetric amplitudes due to attenuation from frequency-independent asymmetry in noise correlations generated by non-isotropic source distribution. The attenuations both between and outside station pairs also produce phase shifts that could affect measurements of group and phase velocities. In terms of noise cross-spectra, the interstation attenuation is governed by Struve functions while the attenuation between the far-field sources and receivers is associated with exponential decay and the imaginary part of complex Bessel function. These results are fundamentally different from previous studies of attenuated coherency that append the Bessel function with an exponential decay that depends on the interstation distance.

  15. Coriolis attenuation in the A congruent 130--150 region

    SciTech Connect

    Saha, M.; Goswami, A.; Bhattacharya, S.; Sen, S. )

    1990-10-01

    The particle-rotor model has been applied to calculate the band structure in a number of highly neutron deficient odd-{ital A} rare-earth nuclei in the {ital A}{congruent}130--150 region. Several transitional nuclei are also included in the study. The only adjustable parameter, used in the calculation, is the Coriolis attenuation coefficient. However, it is seen that the observed band structures in these nuclei can be reproduced practically without any {ital ad} {ital hoc} reduction of the Coriolis matrix elements. The systematics of the Coriolis attenuation in the neutron-deficient, transitional, and well-deformed rare-earth nuclei are discussed in the light of the present work and several theoretical studies, made earlier. The importance of the pairing interaction in the Coriolis attenuation study is emphasized.

  16. Attenuation of Scalar Fluxes Measured with Spatially-displaced Sensors

    NASA Astrophysics Data System (ADS)

    Horst, T. W.; Lenschow, D. H.

    2009-02-01

    Observations from the Horizontal Array Turbulence Study (HATS) field program are used to examine the attenuation of measured scalar fluxes caused by spatial separation between the vertical velocity and scalar sensors. The HATS data show that flux attenuation for streamwise, crosswind, and vertical sensor displacements are each a function of a dimensionless, stability-dependent parameter n m multiplied by the ratio of sensor displacement to measurement height. The scalar flux decays more rapidly with crosswind displacements than for streamwise displacements and decays more rapidly for stable stratification than for unstable stratification. The cospectral flux attenuation model of Kristensen et al. agrees well with the HATS data for streamwise sensor displacements, although it is necessary to include a neglected quadrature spectrum term to explain the observation that flux attenuation is often less with the scalar sensor downwind of the anemometer than for the opposite configuration. A simpler exponential decay model provides good estimates for crosswind sensor displacements, as well as for streamwise sensor displacements with stable stratification. A model similar to that of Lee and Black correctly predicts flux attenuation for a combination of streamwise and crosswind displacements, i.e. as a function of wind direction relative to the sensor displacement. The HATS data for vertical sensor displacements extend the near-neutral results of Kristensen et al. to diabatic stratification and confirm their finding that flux attenuation is less with the scalar sensor located below the anemometer than if the scalar sensor is displaced an equal distance either horizontally or above the anemometer.

  17. Correction for acoustic attenuation effects in optoacoustic tomographic reconstructions

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. Luís; Razansky, Daniel; Ntziachristos, Vasilis

    2011-07-01

    The feasibility of correcting for the effects of acoustic attenuation in optoacoustic tomographic reconstructions obtained with model-based inversion is shown in this work. Acoustic attenuation is a physical phenomenon that takes place inevitably in actual acoustic media and becomes significant at high ultrasonic frequencies. The frequency dependence of acoustic attenuation and the associated dispersion lead to reduction of amplitude and broadening of the optoacoustic signals, which in turn cause, respectively, quantification errors and loss of resolution in the reconstructed images. In this work we imaged an agar phantom with embedded microparticles in three different scenarios, namely with the signals acquired with no attenuation, with the signals collected by placing an attenuating sample in between the phantom and the ultrasonic transducer and with the signals corrected for the effects of acoustic attenuation. The results obtained show that the quantification inaccuracies and the loss of resolution of the images can be partially corrected at the expense of introducing noise at high spatial frequencies due to the amplification of the high frequency components of the noise in the signals.

  18. Proteomic Analysis of Pathogenic and Attenuated Alcelaphine Herpesvirus 1▿

    PubMed Central

    Dry, Inga; Haig, David M.; Inglis, Neil F.; Imrie, Lisa; Stewart, James P.; Russell, George C.

    2008-01-01

    The gammaherpesvirus alcelaphine herpesvirus 1 (AlHV-1) causes malignant catarrhal fever in susceptible ungulates but infects its natural host, wildebeest, without obvious clinical signs. In tissue culture, AlHV-1 is initially predominantly cell associated and virulent but on extended culture becomes cell-free and attenuated. We wanted to determine what changes in protein composition had taken place during the transition from virulent to attenuated virus in culture. Purified virus preparations were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and proteins were analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry. Peptides were identified in serial gel slices by using MASCOT software to interrogate virus-specific and nonredundant sequence databases. Twenty-three AlHV-1-encoded proteins and six cellular proteins were identified in the attenuated and virulent viruses. Two polypeptides were detected in only the virulent virus preparations, while one other protein was found in only the attenuated virus. Two of these virus-specific proteins were identified by a single peptide, suggesting that these may be low-abundance virion proteins rather than markers of attenuation or pathogenesis. The results suggest that attenuation of AlHV-1 is not the result of gross changes in the composition of the virus particle but probably due to altered viral gene expression in the infected cell. PMID:18353942

  19. Diatom Phytochromes Reveal the Existence of Far-Red-Light-Based Sensing in the Ocean.

    PubMed

    Fortunato, Antonio Emidio; Jaubert, Marianne; Enomoto, Gen; Bouly, Jean-Pierre; Raniello, Raffaella; Thaler, Michael; Malviya, Shruti; Bernardes, Juliana Silva; Rappaport, Fabrice; Gentili, Bernard; Huysman, Marie J J; Carbone, Alessandra; Bowler, Chris; d'Alcalà, Maurizio Ribera; Ikeuchi, Masahiko; Falciatore, Angela

    2016-03-01

    The absorption of visible light in aquatic environments has led to the common assumption that aquatic organisms sense and adapt to penetrative blue/green light wavelengths but show little or no response to the more attenuated red/far-red wavelengths. Here, we show that two marine diatom species, Phaeodactylum tricornutum and Thalassiosira pseudonana, possess a bona fide red/far-red light sensing phytochrome (DPH) that uses biliverdin as a chromophore and displays accentuated red-shifted absorbance peaks compared with other characterized plant and algal phytochromes. Exposure to both red and far-red light causes changes in gene expression in P. tricornutum, and the responses to far-red light disappear in DPH knockout cells, demonstrating that P. tricornutum DPH mediates far-red light signaling. The identification of DPH genes in diverse diatom species widely distributed along the water column further emphasizes the ecological significance of far-red light sensing, raising questions about the sources of far-red light. Our analyses indicate that, although far-red wavelengths from sunlight are only detectable at the ocean surface, chlorophyll fluorescence and Raman scattering can generate red/far-red photons in deeper layers. This study opens up novel perspectives on phytochrome-mediated far-red light signaling in the ocean and on the light sensing and adaptive capabilities of marine phototrophs.

  20. Variable light source with a million-to-one intensity ratio

    NASA Technical Reports Server (NTRS)

    Snow, W. B.

    1964-01-01

    A wide range, variable intensity light source of constant color characteristics has been developed for testing and calibrating photomultiplier tubes. A light attenuator first diffuses light from a constant source, then permits variable attenuation through a series of chambers and adjustable apertures.

  1. Evaluation of natural attenuation rate at a gasoline spill site.

    PubMed

    Kao, C M; Prosser, J

    2001-04-20

    Contamination of groundwater by gasoline and other petroleum-derived hydrocarbons released from underground storage tanks (USTs) is a serious and widespread environmental problem. Natural attenuation is a passive remedial approach that depends upon natural processes to degrade and dissipate contaminants in soil and groundwater. Currently, in situ column technique, microcosm, and computer modeling have been applied for the natural attenuation rate calculation. However, the subsurface heterogeneity reduces the applicability of these techniques. In this study, a mass flux approach was used to calculate the contaminant mass reduction and field-scale decay rate at a gasoline spill site. The mass flux technique is a simplified mass balance procedure, which is accomplished using the differences in total contaminant mass flux across two cross-sections of the contaminant plume. The mass flux calculation shows that up to 87% of the dissolved total benzene, toluene, ethylbenzene, and xylene (BTEX) isomers removal was observed via natural attenuation at this site. The efficiency of natural biodegradation was evaluated by the in situ tracer method, and the first-order decay model was applied for the natural attenuation/biodegradation rate calculation. Results reveal that natural biodegradation was the major cause of the BTEX mass reduction among the natural attenuation processes, and approximately 88% of the BTEX removal was due to the natural biodegradation process. The calculated total BTEX first-order attenuation and biodegradation rates were 0.036 and 0.025% per day, respectively. Results suggest that the natural attenuation mechanisms can effectively contain the plume, and the mass flux method is useful in assessing the occurrence and efficiency of the natural attenuation process.

  2. Definition, objectives, and evaluation of natural attenuation.

    PubMed

    Rittmann, Bruce E

    2004-12-01

    Natural attenuation offers large benefits to owners and managers of contaminated sites, but often raises strong objections from those who live and work near a site and are asked to assume most of the long-term risks. Part of the controversy comes about because published definitions of natural attenuation do not identify a realistic end-point objective, and they also are ambiguous about the naturally occurring processes that can achieve the objective. According to guidance from the U.S. National Research Council (NRC 2000), destruction and strong immobilization are the naturally occurring processes that achieve a realistic objective: containing the contaminant relatively nears its source, thereby minimizing exposure risks. The strategy for obtaining solid evidence that the objective is being achieved requires measurements that establish a cause-and-effect relationship between contaminant loss and a destruction or strong-immobilization reaction. The cause-and-effect relationship is best documented with reaction footprints, which typically are concentration changes in reactants or products of the destruction or immobilization reaction. MTBE presents a contemporary example in which footprint evidence for biodegradation is especially crucial, since aerobic biodegradation of MTBE requires special conditions not present at all sites: a high availability of dissolved oxygen and bacteria expressing particular oxygenase enzymes.

  3. Plastid movement impaired 2, a new gene involved in normal blue-light-induced chloroplast movements in Arabidopsis.

    PubMed

    Luesse, Darron R; DeBlasio, Stacy L; Hangarter, Roger P

    2006-08-01

    Chloroplasts move in a light-dependent manner that can modulate the photosynthetic potential of plant cells. Identification of genes required for light-induced chloroplast movement is beginning to define the molecular machinery that controls these movements. In this work, we describe plastid movement impaired 2 (pmi2), a mutant in Arabidopsis (Arabidopsis thaliana) that displays attenuated chloroplast movements under intermediate and high light intensities while maintaining a normal movement response under low light intensities. In wild-type plants, fluence rates below 20 micromol m(-2) s(-1) of blue light lead to chloroplast accumulation on the periclinal cell walls, whereas light intensities over 20 micromol m(-2) s(-1) caused chloroplasts to move toward the anticlinal cell walls (avoidance response). However, at light intensities below 75 micromol m(-2) s(-1), chloroplasts in pmi2 leaves move to the periclinal walls; 100 micromol m(-2) s(-1) of blue light is required for chloroplasts in pmi2 to move to the anticlinal cell walls, indicating a shift in the light threshold for the avoidance response in the mutant. The pmi2 mutation has been mapped to a gene that encodes a protein of unknown function with a large coiled-coil domain in the N terminus and a putative P loop. PMI2 shares sequence and structural similarity with PMI15, another unknown protein in Arabidopsis that, when mutated, causes a defect in chloroplast avoidance under high-light intensities.

  4. Light shift measurements in a Cesium Fountain without the use of mechanical shutters

    NASA Technical Reports Server (NTRS)

    Tjoelker, Robert L.; Enzer, D. G.; Klipstein, W. M.

    2005-01-01

    We present measurements confirming operation of a cesium fountain frequency standard with light shift below 10^-15 (and with evidence suggesting it is several orders of magnitude below this level) but without the use of mechanical shutters. Suppression of the light shift is realized using a master-slave laser configuration by reducing the overall optical power delivered to the physics package as well as spoiling the injection of the slave, causing it to lase far off resonance (1-2 nm) as proposed by the authors several years ago [l]. In the absence of any mitigation, this (AC Stark) shift, due to near-resonant laser light reaching the atoms during their microwave interrogation period, is the largest shift in such frequency standards (2x10^-11 for Our fountain). Mechanical shutters provided adequate light attenuation but have been prone to failure.

  5. Light attenuation in a shallow, turbid reservoir, Lake Houston, Texas

    USGS Publications Warehouse

    Lee, Roger W.; Rast, Walter

    1997-01-01

    with an average error of the computed coefficient to measured value of ±13 percent. The model can be useful in computing the thickness of the euphotic zone to determine primary productivity in the reservoir.

  6. An Underwater Light Attenuation Scheme for Marine Ecosystem Models

    DTIC Science & Technology

    2008-10-01

    absorption curves of phytoplankton pigments , dissolved organic matter, and other paniculate materials," Limnol. Occanogr. 26, 671-689 (1981). 18. A...Introduction The underwater distribution and variability of photosynthetically active radiation (PAR) are important components in numerical models of marine...under-estimation; now the remaining blue-green bands should not be absorbed so strongly. S4, with the coefficients optimized via the bio-optical model

  7. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-04-01

    In this report we will show results of seismic and well log derived attenuation attributes from a deep water Gulf of Mexico data set. This data was contributed by Burlington Resources and Seitel Inc. The data consists of ten square kilometers of 3D seismic data and three well penetrations. We have computed anomalous seismic absorption attributes on the seismic data and have computed Q from the well log curves. The results show a good correlation between the anomalous absorption (attenuation) attributes and the presence of gas as indicated by well logs.

  8. Reverse attenuation in interaction terms due to covariate measurement error.

    PubMed

    Muff, Stefanie; Keller, Lukas F

    2015-11-01

    Covariate measurement error may cause biases in parameters of regression coefficients in generalized linear models. The influence of measurement error on interaction parameters has, however, only rarely been investigated in depth, and if so, attenuation effects were reported. In this paper, we show that also reverse attenuation of interaction effects may emerge, namely when heteroscedastic measurement error or sampling variances of a mismeasured covariate are present, which are not unrealistic scenarios in practice. Theoretical findings are illustrated with simulations. A Bayesian approach employing integrated nested Laplace approximations is suggested to model the heteroscedastic measurement error and covariate variances, and an application shows that the method is able to reveal approximately correct parameter estimates.

  9. The effects of acoustic attenuation in optoacoustic signals.

    PubMed

    Deán-Ben, X Luís; Razansky, Daniel; Ntziachristos, Vasilis

    2011-09-21

    In this paper, it is demonstrated that the effects of acoustic attenuation may play a significant role in establishing the quality of tomographic optoacoustic reconstructions. Accordingly, spatially dependent reduction of signal amplitude leads to quantification errors in the reconstructed distribution of the optical absorption coefficient while signal broadening causes loss of image resolution. Here we propose a correction algorithm for accounting for attenuation effects, which is applicable in both the time and frequency domains. It is further investigated which part of the optoacoustic signal spectrum is practically affected by those effects in realistic imaging scenarios. The validity and benefits of the suggested modelling and correction approaches are experimentally validated in phantom measurements.

  10. Statistics and Physics of Stratospheric Gravity Wave Attenuation over New Zealand

    NASA Astrophysics Data System (ADS)

    Kruse, C. G.; Smith, R. B.

    2015-12-01

    The DEEPWAVE field project took place over the New Zealand region during June and July of 2014 and was focused on observing orographic and non-orographic gravity waves from their source regions in the troposphere to attenuation regions in the stratosphere, mesosphere, and thermosphere. An important preliminary finding of this project is that many mountain wave events are attenuated in a 15-20km "valve layer" in the lower stratosphere, characterized by weak winds and non-linearity. This valve layer strongly attenuates about half of New Zealand mountain wave events, reducing wave momentum fluxes by as much as 90% and producing a maximum in momentum flux divergence. This work further characterizes this lower-stratospheric mountain wave attenuation and seeks to understand the physics of actual wave attenuation events "reproduced" within 6- and 2-km resolution realistic WRF simulations. Local attenuation diagnostics, such as Richardson Number, stratification, and the non-linearity ratio, are used to characterize the size and 3-D distribution of attenuation regions and to diagnose dissipation mechanisms. Potential vorticity (PV) is also used as a diagnostic to identify attenuation regions and also to trace the influences of these regions downstream. Preliminary work has revealed that mountain wave attenuation over New Zealand is spatially inhomogeneous, generates PV in dipoles, and that lateral shear instabilities cause lateral mixing 1000s of kilometers downstream of the attenuation regions.

  11. Contribution of hydrolysis in the abiotic attenuation of RDX and HMX in coastal waters.

    PubMed

    Monteil-Rivera, Fanny; Paquet, Louise; Giroux, Romain; Hawari, Jalal

    2008-01-01

    Sinking of military ships, dumping of munitions during the two World Wars, and military training have resulted in the undersea deposition of numerous unexploded ordnances (UXOs). Leaching of energetic compounds such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from these UXOs may cause adverse ecological effects so that the long-term fate of these chemicals in the sea should be known. The present study assesses the contribution of alkaline hydrolysis into the natural attenuation of RDX and HMX in coastal waters. Alkaline hydrolysis rates were shown to be unaffected by the presence of sodium chloride, the most common component in marine waters. Kinetic parameters (E(a), ln A, k(2)) quantified for the alkaline hydrolysis of RDX and HMX in deionized water (30-50 degrees C, pH 10-12) agreed relatively well with abiotic degradation rates determined in sterilized natural coastal waters (50 and 60 degrees C, variable salinity) even if the latter were generally slightly faster than the former. Furthermore, similar products (HCHO, NO(2)(-), O(2)NNHCH(2)NHCHO) were obtained on alkaline hydrolysis in deionized water and abiotic degradation in coastal waters. These two findings suggested that degradation of nitramines in sterilized natural coastal waters, away from light, was mainly governed by alkaline hydrolysis. Kinetic calculations using the present parameters showed that alkaline hydrolysis of RDX and HMX in marine waters at 10 degrees C would respectively take 112 +/- 10 and 2408 +/- 217 yr to be completed (99.0%). We concluded that under natural conditions hydrolysis should not contribute significantly to the natural attenuation of HMX in coastal waters whereas it could play an active role in the natural attenuation of RDX.

  12. Remote sensing of normalized diffuse attenuation coefficient of downwelling irradiance

    NASA Astrophysics Data System (ADS)

    Lin, Junfang; Lee, Zhongping; Ondrusek, Michael; Du, Keping

    2016-09-01

    The diffuse attenuation of downwelling irradiance, Kd (m-1), is an important property related to light penetration and availability in aquatic ecosystems. The standard Kd(490) product (the diffuse attenuation coefficient at 490 nm) of the global oceans from satellite remote sensing has been produced with an empirical algorithm, which limits its reliability and applicability in coastal regions. More importantly, as an apparent optical property (AOP), Kd is a function of the angular distribution of the light field (e.g., solar zenith angle). The empirically derived product thus contains ambiguities when compared with in situ measurements as there is no specification regarding the corresponding solar zenith angle associated with this Kd(490) product. To overcome these shortcomings, we refined the Kd product with a product termed as the normalized diffuse attenuation coefficient (nKd, m-1), that is equivalent to the Kd in the absence of the atmosphere and with the sun at zenith. Models were developed to get nKd from both in situ measurements and ocean color remote sensing. Evaluations using field measurements indicated that the semianalytically derived nKd product will not only remove the ambiguities when comparing Kd values of different light fields but will also improve the quality of such a product, therefore maximizing the value offered by satellite ocean color remote sensing.

  13. Explosively pumped laser light

    DOEpatents

    Piltch, Martin S.; Michelotti, Roy A.

    1991-01-01

    A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

  14. MICROBIAL PROCESSES AFFECTING MONITORED NATURAL ATTENUATION OF CONTAMINANTS IN THE SUBSURFACE

    EPA Science Inventory

    Natural attenuation, also know as natural assimilation, intrinsic remediation, and passive remediation, along with other appellations, is defined according to the processes of biotic and abiotic transformations while stressing that bioremediation is the major cause for contaminan...

  15. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-07-01

    In fully-saturated rock and at ultrasonic frequencies, the microscopic squirt flow induced between the stiff and soft parts of the pore space by an elastic wave is responsible for velocity-frequency dispersion and attenuation. In the seismic frequency range, it is the macroscopic cross-flow between the stiffer and softer parts of the rock. We use the latter hypothesis to introduce simple approximate equations for velocity-frequency dispersion and attenuation in a fully water saturated reservoir. The equations are based on the assumption that in heterogeneous rock and at a very low frequency, the effective elastic modulus of the fully-saturated rock can be estimated by applying a fluid substitution procedure to the averaged (upscaled) dry frame whose effective porosity is the mean porosity and the effective elastic modulus is the Backus-average (geometric mean) of the individual dry-frame elastic moduli of parts of the rock. At a higher frequency, the effective elastic modulus of the saturated rock is the Backus-average of the individual fully-saturated-rock elastic moduli of parts of the rock. The difference between the effective elastic modulus calculated separately by these two methods determines the velocity-frequency dispersion. The corresponding attenuation is calculated from this dispersion by using (e.g.) the standard linear solid attenuation model.

  16. Attenuation Calibration in the NOvA Detectors

    NASA Astrophysics Data System (ADS)

    Campbell, Medbh; NOvA Collaboration

    2017-01-01

    NOvA is a long baseline neutrino experiment which is constructed from long extruded PVC cells filled with liquid scintillator. When charged particles move through the scintillator, they produce scintillation light. A loop of wavelength shifting optical fibre in each cell transports the scintillation light to the electronic readout. Light is attenuated as it passes through this fibre - this must be calibrated for using cosmic muons. However, cosmic muons do not deposit equal amounts of energy throughout the detector due to threshold effects, detector self-shielding, and variation in individual fibres' transmittance of light. In this talk, we discuss corrections for all three of these effects, and their impact on the accuracy of reconstructed energy.

  17. Predicting light penetration into river waters

    NASA Astrophysics Data System (ADS)

    Davies-Colley, Robert J.; Nagels, John W.

    2008-09-01

    Lighting in rivers often needs to be quantified, particularly for modeling benthic plant growth, but is seldom measured because of difficulties associated with limited depth and strong currents. Therefore, methods for predicting light attenuation from river water quality data would be very useful. We used measurements of the diffuse light attenuation coefficient, Kd (m-1), at 17 optically diverse rivers in New Zealand to develop simple empirical models of light penetration as functions of the beam attenuation coefficient at 550 nm, c550 (m-1, an index of visual water clarity) and the light absorption coefficient of membrane filtrates at 340 nm, g340 (m-1, an index of colored dissolved organic matter). The beam attenuation coefficient can be measured by beam transmissometer or estimated, as in this study, from black disc visibility observations. Alternatively, nephelometric turbidity, Tn (an index of light scattering), which is more commonly measured in water quality monitoring programs, can be used to predict Kd. The models performed satisfactorily when tested over a wide range of optical water quality (varying with flow) at one river site. We expect that these empirical models will have wide practical application for estimating light availability in rivers and streams.

  18. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    SciTech Connect

    Cai, Yujun; Li, Jian-Dong; Yan, Chen

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  19. The responses of light interception, photosynthesis and fruit yield of cucumber to LED-lighting within the canopy.

    PubMed

    Trouwborst, Govert; Oosterkamp, Joke; Hogewoning, Sander W; Harbinson, Jeremy; van Ieperen, Wim

    2010-03-01

    Mathematical models of light attenuation and canopy photosynthesis suggest that crop photosynthesis increases by more uniform vertical irradiance within crops. This would result when a larger proportion of total irradiance is applied within canopies (interlighting) instead of from above (top lighting). These irradiance profiles can be generated by Light Emitting Diodes (LEDs). We investigated the effects of interlighting with LEDs on light interception, on vertical gradients of leaf photosynthetic characteristics and on crop production and development of a greenhouse-grown Cucumis sativus'Samona' crop and analysed the interaction between them. Plants were grown in a greenhouse under low natural irradiance (winter) with supplemental irradiance of 221 micromol photosynthetic photon flux m(-2) s(-1) (20 h per day). In the interlighting treatment, LEDs (80% Red, 20% Blue) supplied 38% of the supplemental irradiance within the canopy with 62% as top lighting by High-Pressure Sodium (HPS)-lamps. The control was 100% top lighting (HPS lamps). We measured horizontal and vertical light extinction as well as leaf photosynthetic characteristics at different leaf layers, and determined total plant production. Leaf mass per area and dry mass allocation to leaves were significantly greater but leaf appearance rate and plant length were smaller in the interlighting treatment. Although leaf photosynthetic characteristics were significantly increased in the lower leaf layers, interlighting did not increase total biomass or fruit production, partly because of a significantly reduced vertical and horizontal light interception caused by extreme leaf curling, likely because of the LED-light spectrum used, and partly because of the relatively low irradiances from above.

  20. Stormwater Attenuation by Green Roofs

    NASA Astrophysics Data System (ADS)

    Sims, A.; O'Carroll, D. M.; Robinson, C. E.; Smart, C. C.

    2014-12-01

    Innovative municipal stormwater management technologies are urgently required in urban centers. Inadequate stormwater management can lead to excessive flooding, channel erosion, decreased stream baseflows, and degraded water quality. A major source of urban stormwater is unused roof space. Green roofs can be used as a stormwater management tool to reduce roof generated stormwater and generally improve the quality of runoff. With recent legislation in some North American cities, including Toronto, requiring the installation of green roofs on large buildings, research on the effectiveness of green roofs for stormwater management is important. This study aims to assess the hydrologic response of an extensive sedum green roof in London, Ontario, with emphasis on the response to large precipitation events that stress municipal stormwater infrastructure. A green roof rapidly reaches field capacity during large storm events and can show significantly different behavior before and after field capacity. At field capacity a green roof has no capillary storage left for retention of stormwater, but may still be an effective tool to attenuate peak runoff rates by transport through the green roof substrate. The attenuation of green roofs after field capacity is linked to gravity storage, where gravity storage is the water that is temporarily stored and can drain freely over time after field capacity has been established. Stormwater attenuation of a modular experimental green roof is determined from water balance calculations at 1-minute intervals. Data is used to evaluate green roof attenuation and the impact of field capacity on peak flow rates and gravity storage. In addition, a numerical model is used to simulate event based stormwater attenuation. This model is based off of the Richards equation and supporting theory of multiphase flow through porous media.

  1. Nicotine Administration Attenuates Methamphetamine-Induced Novel Object Recognition Deficits

    PubMed Central

    Vieira-Brock, Paula L.; McFadden, Lisa M.; Nielsen, Shannon M.; Smith, Misty D.; Hanson, Glen R.

    2015-01-01

    Background: Previous studies have demonstrated that methamphetamine abuse leads to memory deficits and these are associated with relapse. Furthermore, extensive evidence indicates that nicotine prevents and/or improves memory deficits in different models of cognitive dysfunction and these nicotinic effects might be mediated by hippocampal or cortical nicotinic acetylcholine receptors. The present study investigated whether nicotine attenuates methamphetamine-induced novel object recognition deficits in rats and explored potential underlying mechanisms. Methods: Adolescent or adult male Sprague-Dawley rats received either nicotine water (10–75 μg/mL) or tap water for several weeks. Methamphetamine (4×7.5mg/kg/injection) or saline was administered either before or after chronic nicotine exposure. Novel object recognition was evaluated 6 days after methamphetamine or saline. Serotonin transporter function and density and α4β2 nicotinic acetylcholine receptor density were assessed on the following day. Results: Chronic nicotine intake via drinking water beginning during either adolescence or adulthood attenuated the novel object recognition deficits caused by a high-dose methamphetamine administration. Similarly, nicotine attenuated methamphetamine-induced deficits in novel object recognition when administered after methamphetamine treatment. However, nicotine did not attenuate the serotonergic deficits caused by methamphetamine in adults. Conversely, nicotine attenuated methamphetamine-induced deficits in α4β2 nicotinic acetylcholine receptor density in the hippocampal CA1 region. Furthermore, nicotine increased α4β2 nicotinic acetylcholine receptor density in the hippocampal CA3, dentate gyrus and perirhinal cortex in both saline- and methamphetamine-treated rats. Conclusions: Overall, these findings suggest that nicotine-induced increases in α4β2 nicotinic acetylcholine receptors in the hippocampus and perirhinal cortex might be one mechanism by which

  2. Improved Inlet Noise Attenuation by Alteration of Boundary Layer Profiles

    NASA Technical Reports Server (NTRS)

    Mani, Ramani; Luedke, Jon; Jones, Michael G.; Nark, Douglas M.

    2004-01-01

    Acoustic liners are an essential component of technology used to reduce aircraft engine noise. Flow affects attenuation due to the liner in several ways, one of which is that boundary layers adjacent to the liner refract the sound. In the case of inlet noise, the boundary layer causes sound to be refracted away from the liner, thus degrading attenuation. A concept to improve attenuation by the liner by alteration of inlet boundary layer profiles is presented. The alteration of profiles is achieved by inlet blowing. Computational fluid dynamics and duct mode propagation theory for ducts carrying a parallel sheared flow have been used to design experiments to explore such a possibility in the NASA Langley Research Center Grazing Incidence Tube using an inlet blowing scheme developed at General Electric Global Research. The effects of inlet blowing on two liner configurations were evaluated. Calculated results will be shown for blowing ratios (injected flow/duct flow) of approximately 12% and frequencies up to 3 kHz. These results emphasize changes of attenuation achieved by blowing for the two liners. Experimental results of measured flow profiles (with and without blowing) in the Grazing Incidence Tube, and of corresponding changes in attenuation by the liner due to blowing will be presented.

  3. Light Duty.

    ERIC Educational Resources Information Center

    Rogers, Jeff

    1996-01-01

    Discusses multipurpose athletic-field lighting specifications to enhance lighting quality and reduce costs. Topics discussed include lamp choice, lighting spillover and glare prevention, luminary assemblies and poles, and the electrical dimming and switching systems. (GR)

  4. Light Pollution

    ERIC Educational Resources Information Center

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  5. Sortilin Participates in Light-dependent Photoreceptor Degeneration in Vivo

    PubMed Central

    Martín-Oliva, David; de la Villa, Pedro; Cuadros, Miguel A.; Frade, José M.

    2012-01-01

    Both proNGF and the neurotrophin receptor p75 (p75NTR) are known to regulate photoreceptor cell death caused by exposure of albino mice to intense illumination. ProNGF-induced apoptosis requires the participation of sortilin as a necessary p75NTR co-receptor, suggesting that sortilin may participate in the photoreceptor degeneration triggered by intense lighting. We report here that light-exposed albino mice showed sortilin, p75NTR, and proNGF expression in the outer nuclear layer, the retinal layer where photoreceptor cell bodies are located. In addition, cone progenitor-derived 661W cells subjected to intense illumination expressed sortilin and p75NTR and released proNGF into the culture medium. Pharmacological blockade of sortilin with either neurotensin or the “pro” domain of proNGF (pro-peptide) favored the survival of 661W cells subjected to intense light. In vivo, the pro-peptide attenuated retinal cell death in light-exposed albino mice. We propose that an auto/paracrine proapoptotic mechanism based on the interaction of proNGF with the receptor complex p75NTR/sortilin participates in intense light-dependent photoreceptor cell death. We therefore propose sortilin as a putative target for intervention in hereditary retinal dystrophies. PMID:22558402

  6. Low-Light-Shift Cesium Fountain without Mechanical Shutters

    NASA Technical Reports Server (NTRS)

    Enzer, Daphna

    2008-01-01

    A new technique for reducing errors in a laser-cooled cesium fountain frequency standard provides for strong suppression of the light shift without need for mechanical shutters. Because mechanical shutters are typically susceptible to failure after operating times of the order of months, the elimination of mechanical shutters could contribute significantly to the reliability of frequency standards that are required to function continuously for longer time intervals. With respect to the operation of an atomic-fountain frequency standard, the term "light shift" denotes an undesired relative shift in the two energy levels of the atoms (in this case, cesium atoms) in the atomic fountain during interrogation by microwaves. The shift in energy levels translates to a frequency shift that reduces the precision and possibly accuracy of the frequency standard. For reasons too complex to describe within the space available for this article, the light shift is caused by any laser light that reaches the atoms during the microwave- interrogation period, but is strongest for near-resonance light. In the absence of any mitigating design feature, the light shift, expressed as a fraction of the standard fs frequency, could be as large as approx. 2 x 10(exp -11), the largest error in the standard. In a typical prior design, to suppress light shift, the intensity of laser light is reduced during the interrogation period by using a single-pass acoustooptic modulator to deflect the majority of light away from the main optical path. Mechanical shutters are used to block the remaining undeflected light to ensure complete attenuation. Without shutters, this remaining undeflected light could cause a light shift of as much as .10.15, which is unacceptably large in some applications. The new technique implemented here involves additionally shifting the laser wavelength off resonance by a relatively large amount (typically of the order of nanometers) during microwave interrogation. In this

  7. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    SciTech Connect

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  8. Diatom Phytochromes Reveal the Existence of Far-Red-Light-Based Sensing in the Ocean[OPEN

    PubMed Central

    Enomoto, Gen; Bouly, Jean-Pierre; Thaler, Michael; Malviya, Shruti; Bernardes, Juliana Silva; Rappaport, Fabrice; Gentili, Bernard; Huysman, Marie J.J.; Carbone, Alessandra; Bowler, Chris; Ikeuchi, Masahiko; Falciatore, Angela

    2016-01-01

    The absorption of visible light in aquatic environments has led to the common assumption that aquatic organisms sense and adapt to penetrative blue/green light wavelengths but show little or no response to the more attenuated red/far-red wavelengths. Here, we show that two marine diatom species, Phaeodactylum tricornutum and Thalassiosira pseudonana, possess a bona fide red/far-red light sensing phytochrome (DPH) that uses biliverdin as a chromophore and displays accentuated red-shifted absorbance peaks compared with other characterized plant and algal phytochromes. Exposure to both red and far-red light causes changes in gene expression in P. tricornutum, and the responses to far-red light disappear in DPH knockout cells, demonstrating that P. tricornutum DPH mediates far-red light signaling. The identification of DPH genes in diverse diatom species widely distributed along the water column further emphasizes the ecological significance of far-red light sensing, raising questions about the sources of far-red light. Our analyses indicate that, although far-red wavelengths from sunlight are only detectable at the ocean surface, chlorophyll fluorescence and Raman scattering can generate red/far-red photons in deeper layers. This study opens up novel perspectives on phytochrome-mediated far-red light signaling in the ocean and on the light sensing and adaptive capabilities of marine phototrophs. PMID:26941092

  9. Ultraviolet light and osmotic stress: Activation of the JNK cascade through multiple growth factor and cytokine receptors

    SciTech Connect

    Rosette, C.; Karin, M.

    1996-11-15

    Exposure of mammalian cells to ultraviolet (UV) light or high osmolarity strongly activated the c-Jun amino-terminal protein kinase (JNK) cascade, causing induction of many target genes. Exposure to UV light or osmotic shock induced clustering and internalization of cell surface receptors for epidermal growth factor (EGF), tumor necrosis factor (TNF), and interleukin-1 (IL-1). Activation of the EGF and TNF receptors was also detected biochemically. Whereas activation of each receptor alone resulted in modest activation of JNK, coadministration of EGF, IL-1, and TNF resulted in a strong synergistic response equal to that caused by exposure to osmotic shock or UV light. Inhibition of clustering or receptor down-regulation attenuated both the osmotic shock and UV responses. Physical stresses may perturb the cell surface or alter receptor conformation, thereby subverting signaling pathways normally used by growth factors and cytokines. 24 refs., 5 figs.

  10. Chlorine signal attenuation in concrete.

    PubMed

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  11. Ultrasound fields in attenuating media.

    PubMed

    Lerch, R; Friedrich, W

    1986-10-01

    For medical ultrasonic imaging and for nondestructive testing, the attenuation of pressure waves and the resulting shift in wave velocity are important features in commonly used transmission media such as biological tissue. An algorithm for the numerical evaluation of pressure field distributions generated by ultrasonic transducers is presented. The attenuation and dispersion of the sound transmission medium are taken into consideration. The sound fields are computed numerically for continuous wave as well as pulse excitation. The transducer has plane or gently curved geometry and is embedded in a plane rigid baffle. The numerically determined pressure fields are presented as 3D plots, as gray-scale images for a fixed time stamp (like a snapshot), or as isobars regarding the maximum values over time for each local point in the area under investigation. The algorithm described here can be utilized as a tool for design of ultrasound transducers, especially array antennas.

  12. Experimental study of seismic attenuation in partially saturated porous media

    NASA Astrophysics Data System (ADS)

    Barrière, Julien; Bordes, Clarisse; Sénéchal, Pascale

    2010-05-01

    Nowadays, it is well admitted that hydrogeological properties of the porous media (porosity, fluid saturation and permeability) can influence seismic properties. In geophysics, the major theory which links hydrogeological and seismic parameters is poroelasticity proposed by Biot (1956). The Biot relaxation process is due to the relative displacement of fluid in comparison to the solid which causes a significant attenuation of seismic waves, notably in unconsolidated medium. In partially saturated medium, pore fluids are considered as a perfect mixture and so called 'effective fluid'. However, in more consolidated rocks, the Biot theory is not sufficient to explain the attenuation level as measured from field seismic and sonic log data. In the last decade, some authors provide new theories to understand the attenuation caused by the interaction of the different fluids. Most experiments are done in the ultrasonic frequency range, where sources of attenuation (like scattering or local fluid flow) are different as in the low frequency range where the wavelength is greater than heterogeneities size. In this way, we propose a forward-looking experiment with the use of a vertical impulsionnal seismic source which have a strong amplitude spectrum ranging from 100Hz to 8kHz. We study three different unconsolidated porous media at atmospheric pressure: fine-grained sand, coarsed-grained sand and coarse gravel. Water content is measured with a calibrated capacitance probe and temperature effects are corrected. Seismic wave propagation is recorded by piezoelectric accelerometers designed for frequencies below 10kHz. The water injection is done by imbibition. We propose to analyse the attenuation in the [100Hz-1.5kHz] frequency range for the studied media with various water saturation levels. The attenuation varies according to the porous medium and the water content and appears more significant at dry condition and at high saturation level. The weak cohesion at dry condition

  13. Quantifying Seagrass Light Requirements Using an Algorithm to Spatially Resolve Depth of Colonization-Conf Abstract

    EPA Science Inventory

    Depth of colonization (Zc) is a useful seagrass growth metric that describes seagrass response to light attenuation. Similarly, percent surface irradiance (% SI) at Zc is a measure of seagrass light requirements with applications in seagrass ecology and management. Methods for ...

  14. Lighting Conservation

    ERIC Educational Resources Information Center

    Arnold, Frank D.

    1975-01-01

    With the energy crisis has come an awareness of wasteful consumption practices. One area where research is being done is in lighting conservation. Information in this article is concerned with finding more effective and efficient lighting designs which include daylight utilization, task-oriented lighting, and lighting controls. (MA)

  15. Light control of hliA transcription and transcript stability in the cyanobacterium Synechococcus elongatus strain PCC 7942.

    PubMed

    Salem, Kavitha; van Waasbergen, Lorraine G

    2004-03-01

    The high-light-inducible proteins (HLIPs) of cyanobacteria are polypeptides involved in protecting the cells from high-intensity light (HL). The hliA gene encoding the HLIP from Synechococcus elongatus strain PCC 7942 is expressed in response to HL or low-intensity blue or UV-A light. In this study, we explore via Northern analysis details of the transcriptional regulation and transcript stability of the hliA gene under various light conditions. Transcript levels of the hliA gene increased dramatically upon a shift to HL or UV-A light to similar levels, followed by a rapid decrease in UV-A light, but not in HL, consistent with blue/UV-A light involvement in early stages of HL-mediated expression. A 3-min pulse of low-intensity UV-A light was enough to trigger hliA mRNA accumulation, indicating that a blue/UV-A photoreceptor is involved in upregulation of the gene. Low-intensity red light was found to cause a slight, transient increase in transcript levels (raising the possibility of red-light photoreceptor involvement), while light of other qualities had no apparent effect. No evidence was found for wavelength-specific attenuation of hliA transcript levels induced by HL or UV-A light. Transcript decay was slowed somewhat in darkness, and when photosynthetic electron transport was inhibited by darkness or treatment with DCMU, there appeared a smaller mRNA species that may represent a decay intermediate that accumulates when mRNA decay is slowed. Evidence suggests that upregulation of hliA by light is primarily a transcriptional response but conditions that cause ribosomes to stall on the transcript (e.g., a shift to darkness) can help stabilize hliA mRNA and affect expression levels.

  16. Modulation of the initial light reflex during affective picture viewing

    PubMed Central

    Henderson, Robert R.; Bradley, Margaret M.; Lang, Peter J.

    2014-01-01

    An initial reflexive constriction of the pupil to stimulation – the light reflex – is primarily modulated by brightness, but is attenuated when participants are under threat of shock (e.g. "fear-inhibited light reflex").The present study assessed whether the light reflex is similarly attenuated when viewing emotional pictures. Participants viewed erotic, violent, and neutral scenes that were matched in brightness; as an additional control, scrambled versions identical in brightness were also presented. Compared to viewing neutral scenes, the light reflex was reliably modulated by hedonic content, with significant attenuation both when viewing unpleasant, as well as pleasant, pictures. No differences in the light reflex were found among scrambled versions. Modulation of the initial light reflex is therefore not confined to a context of fear, and also is not indicative of differences in brightness when viewing pictures of natural scenes. PMID:24849784

  17. Modulation of the initial light reflex during affective picture viewing.

    PubMed

    Henderson, Robert R; Bradley, Margaret M; Lang, Peter J

    2014-09-01

    An initial reflexive constriction of the pupil to stimulation-the light reflex-is primarily modulated by brightness, but is attenuated when participants are under threat of shock (i.e., fear-inhibited light reflex). The present study assessed whether the light reflex is similarly attenuated when viewing emotional pictures. Pupil diameter was recorded while participants viewed erotic, violent, and neutral scenes that were matched in brightness; scrambled versions identical in brightness were also presented as an additional control. Compared to viewing neutral scenes, the light reflex was reliably modulated by hedonic content, with significant attenuation both when viewing unpleasant as well as pleasant pictures. No differences in the light reflex were found among scrambled versions. Thus, emotional modulation of the initial light reflex is not confined to a context of fear and is not indicative of brightness differences when viewing pictures of natural scenes.

  18. [Blue light and eye health].

    PubMed

    Zou, Leilei; Dai, Jinhui

    2015-01-01

    Blue light, with the wavelength between 400 nm and 500 nm, has caused public concern because of the injury to the retinal cells. Meanwhile, it is important in circadian rhythm regulation, scotopic vision and ocular growth. Is the blue light safe? Should it be eliminated from the daily life? Here we review the effect and safety of the blue light.

  19. Effects of lorazepam and WAY-200070 in larval zebrafish light/dark choice test.

    PubMed

    Chen, Fengjiao; Chen, Sijie; Liu, Shanshan; Zhang, Cuizhen; Peng, Gang

    2015-08-01

    Zebrafish larvae spend more time in brightly illuminated area when placed in a light/dark testing environment. Here we report that the anxiolytic drugs lorazepam and diazepam increased the time larval fish spent in the dark compartment in the light/dark test. Lorazepam did not affect the visual induced optokinetic response of larval fish. Gene expression levels of c-fos and crh were significantly increased in the hypothalamus of fish larvae underwent light/dark choice behavior, whilst lorazepam treatment alleviated the increased c-fos and crh expressions. Furthermore, we found estrogen receptor β gene expression level was increased in fish larvae underwent light/dark choice. We next examined effects of estrogen receptor modulators (estradiol, BPA, PHTPP, and WAY-200070) in the light/dark test. We identified WAY-200070, a highly selective ERβ agonist significantly altered the light/dark choice behavior of zebrafish larvae. Further investigation showed WAY-200070 treatment caused a reduction of crh expression level in the hypothalamus, suggesting activation of ERβ signaling attenuate the stress response. Interestingly, WAY-200070 treatment caused marked increase of c-fos expression in the habenula of fish larvae underwent behavior test. These results suggest WAY-200070 activation of ERβ mediated signaling may regulate anxiety related behavior in zebrafish through modulation of neuronal activity in habenula.

  20. Measuring the attenuation length of water in the CHIPS-M water Cherenkov detector

    NASA Astrophysics Data System (ADS)

    Amat, F.; Bizouard, P.; Bryant, J.; Carroll, T. J.; Rijck, S. De; Germani, S.; Joyce, T.; Kriesten, B.; Marshak, M.; Meier, J.; Nelson, J. K.; Perch, A. J.; Pfützner, M. M.; Salazar, R.; Thomas, J.; Trokan-Tenorio, J.; Vahle, P.; Wade, R.; Wendt, C.; Whitehead, L. H.; Whitney, M.

    2017-02-01

    The water at the proposed site of the CHIPS water Cherenkov detector has been studied to measure its attenuation length for Cherenkov light as a function of filtering time. A scaled model of the CHIPS detector filled with water from the Wentworth 2W pit, proposed site of the CHIPS deployment, in conjunction with a 3.2 m vertical column filled with this water, was used to study the transmission of 405 nm laser light. Results consistent with attenuation lengths of up to 100 m were observed for this wavelength with filtration and UV sterilization alone.

  1. [Inactivation of EV71 by Exposure to Heat and Ultraviolet Light].

    PubMed

    Xie, Jing; Li, Dandi; Xie, Guangcheng; Hu, Yaqian; Zhang, Qing; Kong, Xiangyu; Guo, Nijun; Li, Yuning; Duan, Zhaojun

    2015-09-01

    Enterovirus 71 (EV71) is a major agent of hand, foot and mouth disease that can cause a severe burden of disease to children. To identify an effective method for the control and prevention of EV71, we studied the effect of exposure to heat and ultraviolet (UV) light upon EV71 inactivation. We found that exposure to 50 degrees C could not inactivate the infectivity of EV71. However, exposure to 60 degrees C and 70 degrees C could inactivate EV71 effectively. EV71 could be inactivated after exposure to UV light at a distance between the sample and a lamp of 30 cm for 30 min or 60 min because viral genomic RNA was destroyed. However, fetal bovine serum (FBS) could attenuate the inactivation proffered by heat and UV light. Attenuation effects of FBS were correlated positively with FBS concentration. Hence, EV71 can be inactivated by exposure to heat and UV light, and our results could provide guidance on prevention of the spread of EV71.

  2. Light intensity compressor

    DOEpatents

    Rushford, Michael C.

    1990-01-01

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  3. Light intensity compressor

    DOEpatents

    Rushford, Michael C.

    1990-02-06

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  4. High power cladding light strippers

    NASA Astrophysics Data System (ADS)

    Wetter, Alexandre; Faucher, Mathieu; Sévigny, Benoit

    2008-02-01

    The ability to strip cladding light from double clad fiber (DCF) fibers is required for many different reasons, one example is to strip unwanted cladding light in fiber lasers and amplifiers. When removing residual pump light for example, this light is characterized by a large numerical aperture distribution and can reach power levels into the hundreds of watts. By locally changing the numerical aperture (N.A.) of the light to be stripped, it is possible to achieve significant attenuation even for the low N.A. rays such as escaped core modes in the same device. In order to test the power-handling capability of this device, one hundred watts of pump and signal light is launched from a tapered fusedbundle (TFB) 6+1x1 combiner into a high power-cladding stripper. In this case, the fiber used in the cladding stripper and the output fiber of the TFB was a 20/400 0.06/0.46 N.A. double clad fiber. Attenuation of over 20dB in the cladding was measured without signal loss. By spreading out the heat load generated by the unwanted light that is stripped, the package remained safely below the maximum operating temperature internally and externally. This is achieved by uniformly stripping the energy along the length of the fiber within the stripper. Different adhesive and heat sinking techniques are used to achieve this uniform removal of the light. This suggests that these cladding strippers can be used to strip hundreds of watts of light in high power fiber lasers and amplifiers.

  5. Light Visor

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Seasonal Affective Disorder is a form of depression brought on by reduced light. For some people, this can lead to clinical depression. NASA has conducted research in light therapy and employs it to help astronauts adjust internal rhythms during orbital flight. Dr. George Brainard, a medical researcher and NASA consultant, has developed a portable light therapy device, which is commercially available. The Light Visor allows continuous light therapy and can be powered by either batteries or electricity. Dr. Brainard continues to research various aspects of light therapy.

  6. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-04-01

    In this report we will show some new Q related seismic attributes on the Burlington-Seitel data set. One example will be called Energy Absorption Attribute (EAA) and is based on a spectral analysis. The EAA algorithm is designed to detect a sudden increase in the rate of exponential decay in the relatively higher frequency portion of the spectrum. In addition we will show results from a hybrid attribute that combines attenuation with relative acoustic impedance to give a better indication of commercial gas saturation.

  7. Imaging Rayleigh wave attenuation with USArray

    NASA Astrophysics Data System (ADS)

    Bao, Xueyang; Dalton, Colleen A.; Jin, Ge; Gaherty, James B.; Shen, Yang

    2016-07-01

    The EarthScope USArray provides an opportunity to obtain detailed images of the continental upper mantle at an unprecedented scale. The majority of mantle models derived from USArray data to date contain spatial variations in seismic-wave speed; however, in many cases these data sets do not by themselves allow a non-unique interpretation. Joint interpretation of seismic attenuation and velocity models can improve upon the interpretations based only on velocity and provide important constraints on the temperature, composition, melt content, and volatile content of the mantle. The surface wave amplitudes that constrain upper-mantle attenuation are sensitive to factors in addition to attenuation, including the earthquake source excitation, focusing and defocusing by elastic structure, and local site amplification. Because of the difficulty of isolating attenuation from these other factors, little is known about the attenuation structure of the North American upper mantle. In this study, Rayleigh wave traveltime and amplitude in the period range 25-100 s are measured using an interstation cross-correlation technique, which takes advantage of waveform similarity at nearby stations. Several estimates of Rayleigh wave attenuation and site amplification are generated at each period, using different approaches to separate the effects of attenuation and local site amplification on amplitude. It is assumed that focusing and defocusing effects can be described by the Laplacian of the traveltime field. All approaches identify the same large-scale patterns in attenuation, including areas where the attenuation values are likely contaminated by unmodelled focusing and defocusing effects. Regionally averaged attenuation maps are constructed after removal of the contaminated attenuation values, and the variations in intrinsic shear attenuation that are suggested by these Rayleigh wave attenuation maps are explored.

  8. Light Motives.

    ERIC Educational Resources Information Center

    Filler, Martin

    1979-01-01

    The new energy consciousness has led to a thorough reevaluation of how artificial lighting can be used wisely, while other researchers have explored the potential of daylighting as an alternative interior light source. (Author/MLF)

  9. Light Reflector

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Ultra Sales, Inc.'s fluorescent lighting fixture gets a boost in reflectivity through installation of Lightdriver, a thin tough thermoplastic film plated with aluminum, capable of reflecting 95 percent of visible light striking it. Lightdriver increases brightness without adding bulbs, and allows energy savings by removing some bulbs because the mirrorlike surface cuts light loss generally occasioned by conventional low reflectivity white painted surface above the bulbs in many fluorescent fixtures. Forty-five percent reduction in lighting electricity is attainable.

  10. Dissecting a Light Echo

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for audio animation

    This animation illustrates how a light echo works, and how an optical illusion of material moving outward is created.

    A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one.

    The animation starts by showing the explosion of a star, which results in a flash of light that moves outward in all directions. The direction of our line of sight from Earth is indicated by the blue arrow.

    When the light flash reaches surrounding dust, shown here as three dark clouds, the dust is heated up, creating infrared light that begins to travel toward Earth (indicated by the red arrows). Dust closest to the explosion lights up first, while the explosion's shock wave takes longer to reach more distant material. This results in light from different parts of the cloud reaching Earth at different times, creating the illusion of motion over time.

    As the animation shows, the inclination of the cloud toward our line of sight can result in the material seeming to move both away from and toward the central star.

  11. The genomes of Marek’s disease virus exist as quasispecies at defined intervals during serial passage-induced attenuation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease (MD) is a lymphoproliferative disease of chickens caused by gallid herpesvirus type 2 (GaHV-2). The disease is controlled through mass vaccination with live-attenuated strains. Attenuation of oncogenic GaHV-2 involves the serial passage of a virulent field isolate in avian embryo fib...

  12. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  13. SCHOOL LIGHTING

    ERIC Educational Resources Information Center

    1965

    SEVERAL ARTICLES ON SCHOOL LIGHTING ARE CONTAINED IN THIS JOURNAL. THE TITLES AND AUTHORS INCLUDED ARE AS FOLLOWS--(1) "TODAY'S CONCEPTS IN SCHOOL LIGHTING" BY CHARLES D. GIBSON, (2) "CHALLENGE OF TOMMORROW'S LIGHTING" BY S.K. GUTH AND E.H. WITTE, (3) "PEEK PREVIEW OF THE WINDOWLESS SCHOOL" BY JAMES J. MORISSEAU, (4) "MAINTENANCE BEGINS BEFORE…

  14. NADPH Oxidase Inhibitor Apocynin Attenuates PCB153-Induced Thyroid Injury in Rats

    PubMed Central

    Abliz, Ablikim; Chen, Chen; Deng, Wenhong; Sun, Rongze

    2016-01-01

    PCBs, widespread endocrine disruptors, cause the disturbance of thyroid hormone (TH) homeostasis in humans and animals. However, the exact mechanism of thyroid dysfunction caused by PCBs is still unknown. In order to clarify the hypotheses that NADPH oxidase (NOX) and subsequent NF-κB pathway may play roles in thyroid dysfunction, sixty Sprague-Dawley rats were randomly divided into four groups: control group, PCB153 treated (PCB) group, received apocynin with PCB153 treatment (APO + PCB) group, and drug control (APO) group. Serum thyroid hormone levels were evaluated. The morphological change of thyroid tissue was analyzed under the light and transmission electron microscopy. NOX2, 8-OHdG, and NF-κB expression in the thyroid tissue was evaluated by immune-histochemical staining. Oxidative stress and inflammatory cytokines were detected. The following results were reduced after apocynin treatment: (1) serum thyroid hormone, (2) thyroid pathological injuries, (3) thyroid MDA, (4) thyroid ultrastructural change, (5) serum inflammatory cytokines, and (6) thyroid expression of NOX2, 8-OHdG, and NF-κB. These results suggested that NOX inhibition attenuates thyroid dysfunction induced by PCB in rats, presumably because of its role in preventing ROS generation and inhibiting the activation of NF-κB pathway. Our findings may provide new therapeutic targets for PCBs induced thyroid dysfunction. PMID:27047545

  15. Optical coherence tomography for blood glucose monitoring through signal attenuation

    NASA Astrophysics Data System (ADS)

    De Pretto, Lucas R.; Yoshimura, Tania M.; Ribeiro, Martha S.; de Freitas, Anderson Z.

    2016-03-01

    Development of non-invasive techniques for glucose monitoring is crucial to improve glucose control and treatment adherence in patients with diabetes. Hereafter, Optical Coherence Tomography (OCT) may offer a good alternative for portable glucometers, since it uses light to probe samples. Changes in the object of interest can alter the intensity of light returning from the sample and, through it, one can estimate the sample's attenuation coefficient (μt) of light. In this work, we aimed to explore the behavior of μt of mouse's blood under increasing glucose concentrations. Different samples were prepared in four glucose concentrations using a mixture of heparinized blood, phosphate buffer saline and glucose. Blood glucose concentrations were measured with a blood glucometer, for reference. We have also prepared other samples diluting the blood in isotonic saline solution to check the effect of a higher multiple-scattering component on the ability of the technique to differentiate glucose levels based on μt. The OCT system used was a commercial Spectral Radar OCT with 930 nm central wavelength and spectral bandwidth (FWHM) of 100 nm. The system proved to be sensitive for all blood glucose concentrations tested, with good correlations with the obtained attenuation coefficients. A linear tendency was observed, with an increase in attenuation with higher values of glucose. Statistical difference was observed between all groups (p<0.001). This work opens the possibility towards a non-invasive diagnostic modality using OCT for glycemic control, which eliminates the use of analytes and/or test strips, as in the case with commercially available glucometers.

  16. Comparison of genomes of Brucella melitensis M28 and the B. melitensis M5-90 derivative vaccine strain highlights the translation elongation factor Tu gene tuf2 as an attenuation-related gene.

    PubMed

    Wang, Fangkun; Qiao, Zujian; Hu, Sen; Liu, Wenxing; Zheng, Huajun; Liu, Sidang; Zhao, Xiaomin; Bu, Zhigao

    2013-08-01

    Brucella melitensis causes brucellosis, a disease affecting sheep, cattle, and sometimes humans. Attenuated B. melitensis strain M5-90, derived from virulent strain M28, is widely used as a live vaccine in ruminants in China. Genetic differences between the strains may cast light on the mechanism of attenuation. We recently reported the complete genomic sequences of M28 and M5-90. Genome organization is highly conserved between these isolates, and also with virulent strains 16 M and ATCC 23457. Analysis revealed 23 open reading frames (ORFs) with consistent differences between M5-90 and the virulent strains. Notably, the tuf2 gene encoding translation elongation factor EF-Tu from M5-90 contained 50 single nucleotide polymorphisms (SNPs) and 9 gaps (indels) compared to tuf2 of M28 or of the other virulent strains. There were no changes in tuf1. To evaluate the potential role of EF-Tu in pathogenesis, tuf1 and tuf2 mutants of M28 and an M5-90 strain harboring wild-type tuf2 were constructed, and their virulence/attenuation was evaluated in vivo. We report that the tuf2 gene plays an important role in the attenuation of M5-90 virulence.

  17. Research progress in live attenuated Brucella vaccine development.

    PubMed

    Wang, Zhen; Wu, Qingmin

    2013-01-01

    Brucella spp. are facultative intracellular bacteria that cause brucellosis, which is a globally occurring zoonotic disease that is characterized by abortion in domestic animals and undulant fever, arthritis, endocarditis, and meningitis in humans. There are currently no licensed vaccines against brucellosis for human use, and only a few licensed live Brucella vaccines are available for use in animals. However, the available animal vaccines may cause abortion and are associated with lower protection rates in animals and higher virulence in humans. Much research has been performed recently to develop novel Brucella vaccines for the prevention and control of animal brucellosis. This article discusses the approaches and strategies for novel live attenuated vaccine development.

  18. Global Attenuation Model of the Upper Mantle

    NASA Astrophysics Data System (ADS)

    Adenis, A.; Debayle, E.; Ricard, Y. R.

    2015-12-01

    We present a three-dimensional shear attenuation model based on a massive surface wave data-set (372,629 Rayleigh waveforms analysed in the period range 50-300s by Debayle and Ricard, 2012). For each seismogram, this approach yields depth-dependent path average models of shear velocity and quality factor, and a set of fundamental and higher-mode dispersion and attenuation curves. We combine these attenuation measurements in a tomographic inversion after a careful rejection of the noisy data. We first remove data likely to be biased by a poor knowledge of the source. Then we assume that waves corresponding to events having close epicenters and recorded at the same station sample the same elastic and anelastic structure, we cluster the corresponding rays and average the attenuation measurements. Logarithms of the attenuations are regionalized using the non-linear east square formalism of Tarantola and Valette (1982), resulting in attenuation tomographic maps between 50s and 300s. After a first inversion, outlyers are rejected and a second inversion yields a moderate variance reduction of about 20%. We correct the attenuation curves for focusing effect using the linearized ray theory of Woodhouse and Wong (1986). Accounting for focussing effects allows building tomographic maps with variance reductions reaching 40%. In the period range 120-200s, the root mean square of the model perturbations increases from about 5% to 20%. Our 3-D attenuation models present strong agreement with surface tectonics at period lower than 200s. Areas of low attenuation are located under continents and areas of high attenuation are associated with oceans. Surprisingly, although mid oceanic ridges are located in attenuating regions, their signature, even if enhanced by focusing corrections, remains weaker than in the shear velocity models. Synthetic tests suggests that regularisation contributes to damp the attenuation signature of ridges, which could therefore be underestimated.

  19. General relationships between ultrasonic attenuation and dispersion

    NASA Technical Reports Server (NTRS)

    Odonnell, M.; Jaynes, E. T.; Miller, J. G.

    1978-01-01

    General relationships between the ultrasonic attenuation and dispersion are presented. The validity of these nonlocal relationships hinges only on the properties of causality and linearity, and does not depend upon details of the mechanism responsible for the attenuation and dispersion. Approximate, nearly local relationships are presented and are demonstrated to predict accurately the ultrasonic dispersion in solutions of hemoglobin from the results of attenuation measurements.

  20. Characterization of Rain Attenuation and Depolarization at W/V Bands

    DTIC Science & Technology

    2015-07-30

    5. M. Islam, Z. Elabdin, O. Elshaikh, O. Khalifa, A. Zahirul, S. Khan, and A. Naji. “Prediction of Signal Attenuation Due to Dust Storms Using Mie...from a Derived Two-Dimensional Dust Storm Model,” IEEE Trans. Antennas Propagation, Vol. 49, No. 12, pp. 1703-1711, 2001. 7. Study Group 3 – Radiowave...8-12], which causes uncertainty in the correlation of attenuation and rain-rate measurements. Furthermore, the overall dielectric constant of

  1. Light Source

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Research on food growth for long duration spacecraft has resulted in a light source for growing plants indoors known as Qbeam, a solid state light source consisting of a control unit and lamp. The light source, manufactured by Quantum Devices, Inc., is not very hot, although it generates high intensity radiation. When Ron Ignatius, an industrial partner of WCSAR, realized that terrestrial plant research lighting was not energy efficient enough for space use, he and WCSAR began to experiment with light emitting diodes. A line of LED products was developed, and QDI was formed to market the technology. An LED-based cancer treatment device is currently under development.

  2. Optimal ultrasonic array focusing in attenuative media.

    PubMed

    Ganguli, A; Gao, R X; Liang, K; Jundt, J

    2011-12-01

    This paper presents a parametric study on the efficiency of ultrasound focusing in an attenuative medium, using phased arrays. Specifically, an analytical model of ultrasound wave focusing in a homogeneous, isotropic and attenuative fluid with point sources is presented. Calculations based on the model have shown that in an attenuative medium, an optimum frequency exists for the best focusing performance for a particular size of aperture and focal distance. The effect of different f numbers on the focusing performance in the attenuative medium is further investigated. The information obtained from the analytical model provides insights into the design and installation of a phased transducer array for energy efficient wave focusing.

  3. Differential dust attenuation in CALIFA galaxies

    NASA Astrophysics Data System (ADS)

    Vale Asari, N.; Cid Fernandes, R.; Amorim, A. L.; Lacerda, E. A. D.; Schlickmann, M.; Wild, V.; Kennicutt, R. C.

    2016-06-01

    Dust attenuation has long been treated as a simple parameter in SED fitting. Real galaxies are, however, much more complicated: The measured dust attenuation is not a simple function of the dust optical depth, but depends strongly on galaxy inclination and the relative distribution of stars and dust. We study the nebular and stellar dust attenuation in CALIFA galaxies, and propose some empirical recipes to make the dust treatment more realistic in spectral synthesis codes. By adding optical recombination emission lines, we find better constraints for differential attenuation. Those recipes can be applied to unresolved galaxy spectra, and lead to better recovered star formation rates.

  4. Partial Portal Vein Arterialization Attenuates Acute Bile Duct Injury Induced by Hepatic Dearterialization in a Rat Model

    PubMed Central

    Wei, Jishu; Wu, Junli; Gao, Wentao; Li, Qiang; Jiang, Kuirong

    2016-01-01

    Hepatic infarcts or abscesses occur after hepatic artery interruption. We explored the mechanisms of hepatic deprivation-induced acute liver injury and determine whether partial portal vein arterialization attenuated this injury in rats. Male Sprague-Dawley rats underwent either complete hepatic arterial deprivation or partial portal vein arterialization, or both. Hepatic ischemia was evaluated using biochemical analysis, light microscopy, and transmission electron microscopy. Hepatic ATP levels, the expression of hypoxia- and inflammation-associated genes and proteins, and the expression of bile transporter genes were assessed. Complete dearterialization of the liver induced acute liver injury, as evidenced by the histological changes, significantly increased serum biochemical markers, decreased ATP content, increased expression of hypoxia- and inflammation-associated genes and proteins, and decreased expression of bile transporter genes. These detrimental changes were extenuated but not fully reversed by partial portal vein arterialization, which also attenuated ductular reaction and fibrosis in completely dearterialized rat livers. Collectively, complete hepatic deprivation causes severe liver injury, including bile infarcts and biloma formation. Partial portal vein arterialization seems to protect against acute ischemia-hypoxia-induced liver injury. PMID:27872855

  5. Illuminating system and method for specialized and decorative lighting using liquid light guides

    DOEpatents

    Zorn, Carl J.; Kross, Brian J.; Majewski, Stanislaw; Wojcik, Randolph F.

    1998-01-01

    The present invention comprises an illumination system for specialized decorative lighting including a light source, a flexible plastic tube sheath for distributing the light to a remote location, a transparent liquid core filling the tube that has an index of refraction greater than that of the plastic tube and an arrangement where light coupled from the light source is caused to leak from the liquid light guide at desired locations for the purposes of specialized lighting, such as underwater illumination in swimming pools.

  6. Bubbles attenuate elastic waves at seismic frequencies: First experimental evidence

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Quintal, Beatriz; Chapman, Samuel; Podladchikov, Yury; Burg, Jean-Pierre

    2015-05-01

    The migration of gases from deep to shallow reservoirs can cause damageable events. For instance, some gases can pollute the biosphere or trigger explosions and eruptions. Seismic tomography may be employed to map the accumulation of subsurface bubble-bearing fluids to help mitigating such hazards. Nevertheless, how gas bubbles modify seismic waves is still unclear. We show that saturated rocks strongly attenuate seismic waves when gas bubbles occupy part of the pore space. Laboratory measurements of elastic wave attenuation at frequencies <100 Hz are modeled with a dynamic gas dissolution theory demonstrating that the observed frequency-dependent attenuation is caused by wave-induced-gas-exsolution-dissolution (WIGED). This result is incorporated into a numerical model simulating the propagation of seismic waves in a subsurface domain containing CO2-gas bubbles. This simulation shows that WIGED can significantly modify the wavefield and illustrates how accounting for this physical mechanism can potentially improve the monitoring and surveying of gas bubble-bearing fluids in the subsurface.

  7. Safety of a live attenuated Erysipelothrix rhusiopathiae vaccine for swine.

    PubMed

    Neumann, Eric J; Grinberg, Alex; Bonistalli, Kathryn N; Mack, Hamish J; Lehrbach, Philip R; Gibson, Nicole

    2009-03-30

    Infection with Erysipelothrix rhusiopathiae has a significant economic impact on pig production systems worldwide. Both inactivated and attenuated vaccines are available to prevent development of clinical signs of swine erysipelas. The ability of a live attenuated E. rhusiopathiae strain to become persistently established in pigs after intranasal exposure and its potential to cause clinical signs consistent with swine erysipelas after being administered directly into the nasopharynx of healthy pigs was evaluated. Five, E. rhusiopathiae-negative pigs were vaccinated by deep intranasal inoculation then followed for 14 days. Nasal swabs were collected daily for 5 days and clinical observations were made daily for 14 days post-vaccination. Nasal swabs were cultured for E. rhusiopathiae with the intent of back-passaging any recovered organisms into subsequent replicates. No organism was recovered from nasal swabs in the first vaccination replicate. A second replicate including 10 pigs was initiated and followed in an identical manner to that described above. Again, no E. rhusiopathiae was recovered from any pigs. No pigs in either replicate showed any signs of clinical swine erysipelas. The live attenuated E. rhusiopathiae strain evaluated in this study did not appear to become persistently established in pigs post-vaccination, did not cause any local or systemic signs consistent with swine erysipelas, and was therefore unlikely to revert to a virulent state when used in a field setting.

  8. Attenuation of scopolamine-induced cognitive dysfunction by obovatol.

    PubMed

    Choi, Dong-Young; Lee, Young-Jung; Lee, Sun Young; Lee, Yoot Mo; Lee, Hyun Hee; Choi, Im Seop; Oh, Ki-Wan; Han, Sang Bae; Nam, Sang-Yoon; Hong, Jin Tae

    2012-07-01

    Alzheimer's disease (AD) is the most prevalent cause of dementia in the elderly people. The disease is pathologically characterized by extracellular deposition of beta-amyloid peptide (Aβ), cholinergic neurodegeneration and elevation of acetylcholine esterase (AChE) activity in the affected regions. In this study, we investigated the effects of obovatol on memory dysfunction, which was caused by scopolamine. Obovatol (0.2, 0.5 and 1 mg/kg for 7 day) attenuated scopolamine (1 mg/kg, i.p.)-induced amnesia in a dose-dependent manner, as revealed by the Morris water maze test and step-through passive avoidance test. Mechanism studies exhibited that obovatol dose-dependently alleviated scopolamine-induced increase in Aβ generation and β-secretase activity in the cortex and hippocampus. Obovatol also attenuated scopolamine-induced rise in AChE activity in the cortex and hippocampus. Obovatol might rescue scopolamine-mediated impaired learning and memory function by attenuating Aβ accumulation and stabilizing cholinergic neurotransmission, which suggests that the natural compound could be a useful agent for the prevention of the development or progression of AD neurodegeneration.

  9. Underwater optical wireless communications: depth dependent variations in attenuation.

    PubMed

    Johnson, Laura J; Green, Roger J; Leeson, Mark S

    2013-11-20

    Depth variations in the attenuation coefficient for light in the ocean were calculated using a one-parameter model based on the chlorophyll-a concentration C(c) and experimentally-determined Gaussian chlorophyll-depth profiles. The depth profiles were related to surface chlorophyll levels for the range 0-4  mg/m², representing clear, open ocean. The depth where C(c) became negligible was calculated to be shallower for places of high surface chlorophyll; 111.5 m for surface chlorophyll 0.8attenuation for underwater ocean communication links, calculated to be 0.0092  m⁻¹ at a wavelength of 430 nm. By combining this with satellite surface-chlorophyll data, it is possible to quantify the attenuation between any two locations in the ocean, with applications for low-noise or secure underwater communications and vertical links from the ocean surface.

  10. Hydrochemical and Isotopic Evidence of Natural Attenuation at the Gas Station Contaminated with Fuel Hydrocarbon

    NASA Astrophysics Data System (ADS)

    Ko, K.; Oh, I.; Suk, H.; Lee, K.

    2005-12-01

    Groundwater flow, hydrochemistry and the carbon isotope composition (d13C) of dissolved inorganic carbon (DIC) were measured to know the effect of natural attenuation which is induced by biodegradation of petroleum hydrocarbon at the abandoned gas station contaminated fuel hydrocarbons. The aquifer sediment consists of 4 to 5 m of unconsolidated and weathered soils overlying granite. The monitoring results of water level showed the immediate response of that to rainfall. This implies that the site is an unconfined aquifer or is located at the near of groundwater recharge area. The contaminant transport modeling using GMS showed that the contaminants, BTEX, transported to two main directions, south and southwest from UST and pipeline. These results were proved by the filed observation of the BTEX from the groundwater seepage at the streams of south and southwest area. The geochemical indicator of natural attenuation, red iron precipitate, was also observed at the groundwater seepage. The hydrochemical indicators, Fe(II), Mn(II), sufides, and methane, of terminal electron accepting processes represented the sulfate reducing and methanogenesis environment of the site. d13C values of DIC ranged from -20.2 to -9.3 permil and increased in the source zone by the microbial degradation of hydrocarbon under methanogenic condition. The enrichment of isotopically heavy C is caused by the production of light 12CH4 from microbial respiration. The molar ratio of Ca to HCO3 is about 2.5 and this indicates the contribution of microbial oxidation of fuel hydrocarbon to DIC in groundwater. The geochemical modeling using PHREEQC showed the oversaturation of siderite, rhodocrosite and goethite and the saturation index of calcite increased as the increase of bicarbonate, indicating the enhanced microbial degradation. From the research results, the mineralogical, hydrological and microbiological factors can exert influence on groundwater chemistry and d13C of DIC.

  11. Ultrasonic attenuation in molecular crystals

    NASA Astrophysics Data System (ADS)

    Perrin, Bernard

    1981-11-01

    It is now well established from an experimental point of view that, concerning the ultrasonic attenuation, molecular crystals exhibit a specific behavior among dielectric crystals. This fact suggests the presence of a relaxation process. Liebermann, who has introduced this field, has proposed a way to analyze this problem and in particular has given an expression for the ultrasonic absorption coefficient in terms of a relaxation time and some thermodynamic quantities. In contrast to Liebermann's approach, a solid-state viewpoint is presented here, and it is shown that this ultrasonic relaxation can be taken into account in the framework of Akhieser's theory. A general expression of the ultrasonic absorption coefficient is calculated in terms of the phonon collision operator using the Boltzmann-equation approach of Woodruff and Ehrenreich. The collision-time approximation widely used in dielectric crystals fails in molecular crystals for which the presence of slow relaxation times in the collision operator prevents the thermalization of the whole set of phonons and gives rise to an ultrasonic relaxation. Thus a more suitable approximation is suggested here, which leads to a new expression of the ultrasonic attenuation valid in molecular crystals. Different forms of this expression are discussed, and comparison with Liebermann's expression used in most of the previous papers shows that the present treatment takes better account of the anisotropy of the solid state. The fit of experimental results obtained for some ionic-molecular crystals also shows that the expression derived here gives better agreement than does Liebermann's. Finally, it is shown that in the framework of the present treatment and under rather general conditions, the anisotropy affects primarily the magnitude of the ultrasonic absorption due to the molecular relaxation, but it does not affect its frequency dependence.

  12. Is it a biological response or chemical process? Chemical and transcriptional regulation experiments probe the cause for the increased accumulation of chlorogenic acid (CGA) in carrot root slices exposed to UV-B light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recently demonstrated that wounded carrot roots subjected to a brief UV-B light treatment accumulate large quantities of chlorogenic acid (CGA) in the treated tissues. Chlorogenic acid is an intermediate in the phenylpropanoid pathway and a potent anti-oxidant. Chemical analysis and real-time P...

  13. Dividing of Q factor of viscous and intrinsic attenuation in poroelastic media

    NASA Astrophysics Data System (ADS)

    Ishikura, K.; Mikada, H.; Goto, T.; Takekawa, J.

    2013-12-01

    Sonic logging has been widely used for many years to understand physical properties of hydrocarbon reservoirs. When gaseous phase exists in the formation fluid, the compressional waves traveling through the formation could be strongly attenuated due to low bulk modulus of gas in the fluid, while the shear waves are not. For acquiring physical properties of fluid in the formation, Biot physics or poroelastic analysis could be the best method. Among the available technologies, quality factors based on the Biot's equation could be used. Although the Biot's theory considers the viscous attenuation induced at the interface between rocks and pore fluids, the intrinsic attenuation caused by the internal friction in the matrix is ignored. In the present study, we investigate how large are the effects of the intrinsic attenuation of compressional waves through the evaluation of the reservoir properties based on the quality factor. We employ a 2D finite-difference scheme to simulate seismic wave propagation in a poroelasic medium. The intrinsic attenuation is included in our model by using the filter of frequency-independent quality factor (constant-Q). We then compare the results compressional waves and shear waves with the intrinsic attenuation in our numerical simulations. Our results clearly show that on compressional and shear waves, the amplitude and phase of the waveforms are strongly affected by the intrinsic attenuation, and we could get only the viscous attenuation by the results of quality factor of compressional wave and shear wave. We conclude that the evaluations of hydrocarbon reservoir require the consideration of the intrinsic attenuation as well as the viscous attenuation predicted by the Biot's theory and also we could get what kind of fluid is contained in the reservoir. The profile of Q factor

  14. Soft Tissue Conduction as a Possible Contributor to the Limited Attenuation Provided by Hearing Protection Devices

    PubMed Central

    Chordekar, Shai; Adelman, Cahtia; Sohmer, Haim; Kishon-Rabin, Liat

    2016-01-01

    Context: Damage to the auditory system by loud sounds can be avoided by hearing protection devices (HPDs) such as earmuffs, earplugs, or both for maximum attenuation. However, the attenuation can be limited by air conduction (AC) leakage around the earplugs and earmuffs by the occlusion effect (OE) and by skull vibrations initiating bone conduction (BC). Aims: To assess maximum attenuation by HPDs and possible flanking pathways to the inner ear. Subjects and Methods: AC attenuation and resulting thresholds were assessed using the real ear attenuation at threshold (REAT) procedure on 15 normal-hearing participants in four free-field conditions: (a) unprotected ears, (b) ears covered with earmuffs, (c) ears blocked with deeply inserted customized earplugs, and (d) ears blocked with both earplugs and earmuffs. BC thresholds were assessed with and without earplugs to assess the OE. Results: Addition of earmuffs to earplugs did not cause significantly greater attenuation than earplugs alone, confirming minimal AC leakage through the external meatus and the absence of the OE. Maximum REATs ranged between 40 and 46 dB, leading to thresholds of 46–54 dB HL. Furthermore, calculation of the acoustic impedance mismatch between air and bone predicted at least 60 dB attenuation of BC. Conclusion: Results do not support the notion that skull vibrations (BC) contributed to the limited attenuation provided by traditional HPDs. An alternative explanation, supported by experimental evidence, suggests transmission of sound to inner ear via non-osseous pathways such as skin, soft tissues, and fluid. Because the acoustic impedance mismatch between air and soft tissues is smaller than that between air and bone, air-borne sounds would be transmitted to soft tissues more effectively than to bone, and therefore less attenuation is expected through soft tissue sound conduction. This can contribute to the limited attenuation provided by traditional HPDs. The present study has practical

  15. Material identification based upon energy-dependent attenuation of neutrons

    DOEpatents

    Marleau, Peter

    2015-10-06

    Various technologies pertaining to identifying a material in a sample and imaging the sample are described herein. The material is identified by computing energy-dependent attenuation of neutrons that is caused by presence of the sample in travel paths of the neutrons. A mono-energetic neutron generator emits the neutron, which is downscattered in energy by a first detector unit. The neutron exits the first detector unit and is detected by a second detector unit subsequent to passing through the sample. Energy-dependent attenuation of neutrons passing through the sample is computed based upon a computed energy of the neutron, wherein such energy can be computed based upon 1) known positions of the neutron generator, the first detector unit, and the second detector unit; or 2) computed time of flight of neutrons between the first detector unit and the second detector unit.

  16. A novel live-attenuated vaccine candidate for mayaro Fever.

    PubMed

    Weise, William J; Hermance, Meghan E; Forrester, Naomi; Adams, A Paige; Langsjoen, Rose; Gorchakov, Rodion; Wang, Eryu; Alcorn, Maria D H; Tsetsarkin, Konstantin; Weaver, Scott C

    2014-08-01

    Mayaro virus (MAYV) is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  17. Attenuation of monkeypox virus by deletion of genomic regions

    USGS Publications Warehouse

    Lopera, Juan G.; Falendysz, Elizabeth A.; Rocke, Tonie E.; Osorio, Jorge E.

    2015-01-01

    Monkeypox virus (MPXV) is an emerging pathogen from Africa that causes disease similar to smallpox. Two clades with different geographic distributions and virulence have been described. Here, we utilized bioinformatic tools to identify genomic regions in MPXV containing multiple virulence genes and explored their roles in pathogenicity; two selected regions were then deleted singularly or in combination. In vitro and in vivostudies indicated that these regions play a significant role in MPXV replication, tissue spread, and mortality in mice. Interestingly, while deletion of either region led to decreased virulence in mice, one region had no effect on in vitro replication. Deletion of both regions simultaneously also reduced cell culture replication and significantly increased the attenuation in vivo over either single deletion. Attenuated MPXV with genomic deletions present a safe and efficacious tool in the study of MPX pathogenesis and in the identification of genetic factors associated with virulence.

  18. Sustainability of natural attenuation of nitrate in agricultural aquifers

    USGS Publications Warehouse

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  19. Development of live attenuated influenza vaccines against pandemic influenza strains.

    PubMed

    Coelingh, Kathleen L; Luke, Catherine J; Jin, Hong; Talaat, Kawsar R

    2014-07-01

    Avian and animal influenza viruses can sporadically transmit to humans, causing outbreaks of varying severity. In some cases, further human-to-human virus transmission does not occur, and the outbreak in humans is limited. In other cases, sustained human-to-human transmission occurs, resulting in worldwide influenza pandemics. Preparation for future pandemics is an important global public health goal. A key objective of preparedness is to gain an understanding of how to design, test, and manufacture effective vaccines that could be stockpiled for use in a pandemic. This review summarizes results of an ongoing collaboration to produce, characterize, and clinically test a library of live attenuated influenza vaccine strains (based on Ann Arbor attenuated Type A strain) containing protective antigens from influenza viruses considered to be of high pandemic potential.

  20. Attenuated oncolytic Measles Virus strains as cancer therapeutics

    PubMed Central

    Msaouel, P.; Iankov, I.D.; Dispenzieri, A.; Galanis, E.

    2011-01-01

    Attenuated measles virus vaccine strains have emerged as a promising oncolytic vector platform, having shown significant anti-tumor activity against a broad range of malignant neoplasms. Measles virus strains derived from the attenuated Edmonston-B (MV-Edm) vaccine lineage have been shown to selectively infect, replicate in and lyse cancer cells while causing minimal cytopathic effect on normal tissues. This review summarizes the preclinical data that led to the rapid clinical translation of oncolytic measles vaccine strains and provides an overview of early clinical data using this oncolytic platform. Furthermore, novel approaches currently under development to further enhance the oncolytic efficacy of MV-Edm strains, including strategies to circumvent immunity or modulate immune system responses, combinatorial approaches with standard treatment modalities, virus retargeting as well as strategies for in vivo monitoring of viral replication are discussed. PMID:21740361

  1. A Novel Live-Attenuated Vaccine Candidate for Mayaro Fever

    PubMed Central

    Weise, William J.; Hermance, Meghan E.; Forrester, Naomi; Adams, A. Paige; Langsjoen, Rose; Gorchakov, Rodion; Wang, Eryu; Alcorn, Maria D. H.; Tsetsarkin, Konstantin; Weaver, Scott C.

    2014-01-01

    Mayaro virus (MAYV) is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease. PMID:25101995

  2. Lg Attenuation Characteristic of Gujarat Region (Western India)

    NASA Astrophysics Data System (ADS)

    Jaiswal, Namrata; Singh, Chandrani

    2016-04-01

    We estimate the Lg attenuation characteristics of the Gujarat Region in Western India by using a reliable two-station method. This region comes under the V, IV and III seismicity zone. So, in India this is the seismic active region other than Himalayas, which shows high seismicity. Lg is typically the most prominent short-period seismic phase on high frequency seismogram observed over the continental paths from regional to teleseimic distance. We use data from 15 earthquakes with magnitude > 5 mb and focal depth < 30 km collected during 2008-2010 from 41 stations deployed in the study region. We estimate 1-Hz Lg Q (Q0) values between many pairs of stations. Finally, 5 events with 70 high-quality inter-station paths were selected from 117 possible pairs of stations that are (1) aligned approximately with the source and (2) separated enough to permit the use of the standard two-station method for Lg Q measurement. Spatial variations in Q0 have been noticed across the Gujarat region. Low Q0 (< 50) values are observed in the Kutch, Jamnagar and southeast region of Gujarat. The northern region of Saurashtra (Gujarat) shows a high Q0 (> 300) value. These observations are consistent with the results of the body wave attenuation structure reported for the region. The variations in the attenuation characteristics may be caused due to both the intrinsic and scattering contributions caused by thermal effects, sedimentary layer thickness as well as heterogeneities present below the study region. Our results are found to be comparable with the previous studies of the attenuation characteristics of the Gujarat region.

  3. Inhibition of phosphodiesterase-1 attenuates cold-induced pulmonary hypertension.

    PubMed

    Crosswhite, Patrick; Sun, Zhongjie

    2013-03-01

    Chronic exposure to cold caused pulmonary arterial hypertension (cold-induced pulmonary hypertension [CIPH]) and increased phosphodiesterase-1C (PDE-1C) expression in pulmonary arteries (PAs) in rats. The purpose of this study is to investigate a hypothesis that inhibition of PDE-1 would decrease inflammatory infiltrates and superoxide production leading to attenuation of CIPH. Three groups of male rats were exposed to moderate cold (5±1°C) continuously, whereas 3 groups were maintained at room temperature (23.5±1°C, warm; 6 rats/group). After 8-week exposure to cold, 3 groups in each temperature condition received continuous intravenous infusion of 8-isobutyl-methylxanthine (8-IBMX) (PDE-1 inhibitor), apocynin (NADPH oxidase inhibitor) or vehicle, respectively, for 1 week. Cold exposure significantly increased right-ventricular systolic pressure compared with warm groups (33.8±3.2 versus 18.6±0.3 mm Hg), indicating that animals developed CIPH. Notably, treatment with 8-IBMX significantly attenuated the cold-induced increase in right ventricular pressure (23.5±1.8 mm Hg). Cold exposure also caused right-ventricular hypertrophy, whereas 8-IBMX reversed cold-induced right ventricular hypertrophy. Cold exposure increased PDE-1C protein expression, macrophage infiltration, NADPH oxidase activity, and superoxide production in PAs and resulted in PA remodeling. 8-IBMX abolished cold-induced upregulation of PDE-1C in PAs. Interestingly, inhibition of PDE-1 eliminated cold-induced macrophage infiltration, NADPH oxidase activation, and superoxide production in PAs and reversed PA remodeling. Inhibition of NADPH oxidase by apocynin abolished cold-induced superoxide production and attenuated CIPH and PA remodeling. In conclusion, inhibition of PDE-1 attenuated CIPH and reversed cold-induced PA remodeling by suppressing macrophage infiltration and superoxide production, suggesting that upregulation of PDE-1C expression may be involved in the pathogenesis of CIPH.

  4. WOW: light print, light propel, light point

    NASA Astrophysics Data System (ADS)

    Glückstad, Jesper; Bañas, Andrew; Aabo, Thomas; Palima, Darwin

    2012-10-01

    We are presenting so-called Wave-guided Optical Waveguides (WOWs) fabricated by two-photon polymerization and capable of being optically manipulated into any arbitrary orientation. By integrating optical waveguides into the structures we have created freestanding waveguides which can be positioned anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation. In a broader context, this research shows that optically trapped micro-fabricated structures can potentially help bridge the diffraction barrier. This structure-mediated paradigm may be carried forward to open new possibilities for exploiting beams from far-field optics down to the sub-wavelength domain.

  5. LONG TERM MONITORING FOR NATURAL ATTENUATION

    EPA Science Inventory

    We have good statistical methods to: (1) determine whether concentrations of a contaminant are attenuating over time, (2) determine the rate of attenuation and confidence interval on the rate, and (3) determine whether concentrations have met a particular clean up goal. We do no...

  6. Emergency Lighting

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A lighting system originally developed for NASA's Apollo and Skylab manned spacecraft resulted in a industrial spinoff and creation of a whole new company to produce and market the product line. The company is UDEC Corp., Waltham, Mass. UDEC's "Multi-Mode" electronic lighting systems are designed for plant emergency and supplemental use, such as night lighting, "always-on" stairwell lights and illuminated exit signs. Their advantages stem from the qualities demanded for spacecraft installation: extremely high fight output with very low energy drain, compactness, light weight, and high reliability. The Multi-Mode system includes long-life fluorescent lamps operated by electronic circuitry, a sealed battery that needs no maintenance for 10 years, and a solid-state battery charger. A typical emergency installation consists of a master module with battery and an eight watt lamp, together with four remote "Satellight" modules powered by the master's battery. As a night lighting system for maintenance or I security, UDEC fixtures can bypass the battery and 1 operate on normal current at a fraction of the energy 1 demand of conventional night lighting. Industrial customers have realized savings of better than ninety percent with UDEC night lights. UDEC started as a basement industry in 1972 but the company has already sold more than 1,000 lighting systems to building operators.

  7. Spectral method for the correction of the Cerenkov light effect in plastic scintillation detectors: A comparison study of calibration procedures and validation in Cerenkov light-dominated situations

    SciTech Connect

    Guillot, Mathieu; Gingras, Luc; Archambault, Louis; Beddar, Sam; Beaulieu, Luc

    2011-04-15

    Carlo results. Conclusions: The authors conclude that the spectral method can be used to accurately correct the Cerenkov light effect in PSDs. The authors confirmed the importance of maximizing the difference of Cerenkov light production between calibration measurements. The authors also found that the attenuation of the optical fiber, which is assumed to be constant in the original formulation of the spectral method, may cause a variation of the calibration factors in some experimental setups.

  8. What Causes Lupus Flares?

    PubMed

    Fernandez, David; Kirou, Kyriakos A

    2016-03-01

    Systemic lupus erythematosus (SLE), the prototypic systemic autoimmune disease, follows a chronic disease course, punctuated by flares. Disease flares often occur without apparent cause, perhaps from progressive inherent buildup of autoimmunity. However, there is evidence that certain environmental factors may trigger the disease. These include exposure to UV light, infections, certain hormones, and drugs which may activate the innate and adaptive immune system, resulting in inflammation, cytotoxic effects, and clinical symptoms. Uncontrolled disease flares, as well as their treatment, especially with glucocorticoids, can cause significant organ damage. Tight surveillance and timely control of lupus flares with judicial use of effective treatments to adequately suppress the excessive immune system activation are required to bring about long term remission of the disease. We hope that new clinical trials will soon offer additional effective and target-specific biologic treatments for SLE.

  9. Breaking the Curve with CANDELS: A Bayesian Approach to Reveal the Non-Universality of the Dust-Attenuation Law at High Redshift

    NASA Astrophysics Data System (ADS)

    Salmon, Brett; Papovich, Casey; Long, James; Willner, S. P.; Finkelstein, Steven L.; Ferguson, Henry C.; Dickinson, Mark; Duncan, Kenneth; Faber, S. M.; Hathi, Nimish; Koekemoer, Anton; Kurczynski, Peter; Newman, Jeffery; Pacifici, Camilla; Pérez-González, Pablo G.; Pforr, Janine

    2016-08-01

    Dust attenuation affects nearly all observational aspects of galaxy evolution, yet very little is known about the form of the dust-attenuation law in the distant universe. Here, we model the spectral energy distributions of galaxies at z ˜ 1.5-3 from CANDELS with rest-frame UV to near-IR imaging under different assumptions about the dust law, and compare the amount of inferred attenuated light with the observed infrared (IR) luminosities. Some individual galaxies show strong Bayesian evidence in preference of one dust law over another, and this preference agrees with their observed location on the plane of infrared excess (IRX, {L}{TIR}/{L}{UV}) and UV slope (β). We generalize the shape of the dust law with an empirical model, {A}λ ,δ =E{(B-V){k}λ (λ /{λ }V)}δ where k λ is the dust law of Calzetti et al., and show that there exists a correlation between the color excess E(B-V) and tilt δ with δ =(0.62+/- 0.05){log}(E(B-V))+(0.26+/- 0.02). Galaxies with high color excess have a shallower, starburst-like law, and those with low color excess have a steeper, SMC-like law. Surprisingly, the galaxies in our sample show no correlation between the shape of the dust law and stellar mass, star formation rate, or β. The change in the dust law with color excess is consistent with a model where attenuation is caused by scattering, a mixed star-dust geometry, and/or trends with stellar population age, metallicity, and dust grain size. This rest-frame UV-to-near-IR method shows potential to constrain the dust law at even higher redshifts (z\\gt 3).

  10. [Characteristics of diffuse attenuation coefficient of underwater irradiance in the lakes in the middle and lower reaches of Yangtze river ].

    PubMed

    Shi, Zhi-Qiang; Zhang, Yun-Lin; Wang, Ming-Zhu; Liu, Xiao-Han

    2013-02-01

    Based on the underwater irradiance profile measurement and water samples collection in September, October 2007 in Lake Donghu, Lake Liangzi and Lake Honghu, and in April in 2010 in Lake Kuileihu, the diffuse attenuation coefficient and the dominant attenuation factors were analyzed. The ranges of diffuse attenuation coefficient and total suspended solid (TSS), organic suspended solid (OSS), inorganic suspended solid (ISS), chlorophyll a (Chla), and dissolved organic carbon (DOC) concentration varied less in Lake Donghu and Lake Kuileihu than in Lake liangzi and Lake Honghu. The regression analysis showed that ISS was the dominant affecting factor of transparency in Lake Donghu and Lake Kuileihu, but ISS and OSS jointly controlled the transparency in Lake Liangzi and Lake Honghu. The diffuse attenuation coefficient minimum occurred near 580 nm. At around 675 nm, the diffuse attenuation coefficient peak was due to phytoplankton absorption, especially at sites with high pigment concentration. The euphotic depth was less than the mean water depth in Lake Donghu, suggesting that the submerged aquatic vegetation (SAV) can not grow in the present underwater light climate. However, the euphotic depth was larger than the mean water depth in other three lakes showing that the underwater light climate can meet the light requirements for the growth of SAV. The regression analysis showed that ISS was the dominant affecting factor of PAR attenuation in Lake Donghu and Lake Kuileihu, but ISS, OSS and Chla jointly controlled PAR attenuation in lake Liangzi and lake Honghu. The significant correlation between the beam attenuatin coefficient at 750 nm and PAR difffuse attenuation coefficient showed that the particles scattering significantly contributed to underwater irradiance attenuation.

  11. Ocular hazards of light

    NASA Technical Reports Server (NTRS)

    Sliney, David H.

    1994-01-01

    The eye is protected against bright light by the natural aversion response to viewing bright light sources. The aversion response normally protects the eye against injury from viewing bright light sources such as the sun, arc lamps and welding arcs, since this aversion limits the duration of exposure to a fraction of a second (about 0.25 s). The principal retinal hazard resulting from viewing bright light sources is photoretinitis, e.g., solar retinitis with an accompanying scotoma which results from staring at the sun. Solar retinitis was once referred to as 'eclipse blindness' and associated 'retinal burn'. Only in recent years has it become clear that photoretinitis results from a photochemical injury mechanism following exposure of the retina to shorter wavelengths in the visible spectrum, i.e., violet and blue light. Prior to conclusive animal experiments at that time, it was thought to be a thermal injury mechanism. However, it has been shown conclusively that an intense exposure to short-wavelength light (hereafter referred to as 'blue light') can cause retinal injury. The product of the dose-rate and the exposure duration always must result in the same exposure dose (in joules-per-square centimeter at the retina) to produce a threshold injury. Blue-light retinal injury (photoretinitis) can result from viewing either an extremely bright light for a short time, or a less bright light for longer exposure periods. This characteristic of photochemical injury mechanisms is termed reciprocity and helps to distinguish these effects from thermal burns, where heat conduction requires a very intense exposure within seconds to cause a retinal coagulation otherwise, surrounding tissue conducts the heat away from the retinal image. Injury thresholds for acute injury in experimental animals for both corneal and retinal effects have been corroborated for the human eye from accident data. Occupational safety limits for exposure to UVR and bright light are based upon this

  12. Aerosols attenuating the solar radiation collected by solar tower plants: The horizontal pathway at surface level

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Ramon, Didier; Dubus, Laurent; Bourdil, Charles; Cuevas-Agulló, Emilio; Zaidouni, Taoufik; Formenti, Paola

    2016-05-01

    Aerosols attenuate the solar radiation collected by solar tower plants (STP), along two pathways: 1) the atmospheric column pathway, between the top of the atmosphere and the heliostats, resulting in Direct Normal Irradiance (DNI) changes; 2) the grazing pathway close to surface level, between the heliostats and the optical receiver. The attenuation along the surface-level grazing pathway has been less studied than the aerosol impact on changes of DNI, while it becomes significant in STP of 100 MW or more. Indeed aerosols mostly lay within the surface atmospheric layer, called the boundary layer, and the attenuation increases with the distance covered by the solar radiation in the boundary layer. In STP of 100 MW or more, the distance between the heliostats and the optical receiver becomes large enough to produce a significant attenuation by aerosols. We used measured aerosol optical thickness and computed boundary layer height to estimate the attenuation of the solar radiation at surface level at Ouarzazate (Morocco). High variabilities in aerosol amount and in vertical layering generated a significant magnitude in the annual cycle and significant inter-annual changes. Indeed the annual mean of the attenuation caused by aerosols over a 1-km heliostat-receiver distance was 3.7% in 2013, and 5.4% in 2014 because of a longest desert dust season. The monthly minimum attenuation of less than 3% was observed in winter and the maximum of more than 7% was observed in summer.

  13. Action-sound coincidence-related attenuation of auditory ERPs is not modulated by affordance compatibility.

    PubMed

    Horváth, János

    2013-04-01

    A couple of studies showed that auditory processing of sounds presented concurrently with one's own actions is attenuated. Because in these studies actions were key-presses, it was hypothesized that attenuation might be caused by robust key-press-effect associations formed by long-term interactions with everyday devices. Key-pressing may be special because most everyday devices are designed to comply with the perceived affordance that a key/button should be pressed to trigger an effect. Therefore, key-presses would attenuate auditory processing, but key-releases would not. In the present experiment, participants marked time intervals by pressing or releasing a key. Independently, a random sequence of tones was presented. Tones coinciding with a key-press or -release elicited similarly attenuated Tb, vertex N1, and P2 ERPs, suggesting that coincidence-related auditory attenuation is not brought about by special key-press-effect associations. Whereas Tb and P2 attenuations were pure amplitude modulations, vertex N1 was attenuated (partly) by an overlapping coincidence-related ERP.

  14. The effect of scatter and attenuation on aerosol deposition as determined by gamma scintigraphy.

    PubMed

    Lee, Z; Berridge, M S; Nelson, A D; Heald, D L

    2001-01-01

    Gamma scintigraphy is often used to quantify deposition patterns from aerosol inhalers. The errors caused by scatter and tissue attenuation in planar Tc-99m gamma scintigraphy were investigated based on the data collected from four subjects in this study. Several error correction methods were tested. The results from two scatter correction methods, Jaszczak's method and factor analysis of dynamic sequences (FADS), were similar. Scatter accounted for 20% of raw data in the whole lung, 20% in the oropharynx, and 43% in the central airways and esophagus. Three attenuation correction methods were investigated and compared. These were: uniform attenuation correction (UAC), a known method used for inhalation drug imaging work; the broad-beam attenuation correction used for organ imaging in nuclear medicine; and a narrow-beam inhomogeneous tissue attenuation correction proposed in this study. The three methods differed significantly (p < 0.05), but all indicated that attenuation is a severe quantification problem. The narrow beam attenuation correction with scatter correction, showed that raw data underestimated tracer deposition by 44% in the lung, 137% in the oropharynx, and 153% in the trachea/esophageal region. To quantify aerosol lung deposition using planar scintigraphy even in relative terms, corrections are necessary. Much of the literature concerning quantified aerosol dose distributions measured by gamma scintigraphy needs to be interpreted carefully.

  15. Cauldron of Light

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image to view the animation

    In this animation, a seething cauldron of light appears to bubble and ooze around the remains of a giant star that astronomers have been watching tear itself apart for the last 300 years. This movie flips quickly between different observations taken over three years by NASA's Spitzer Space Telescope.

    Beginning in the center, the well-studied Cassiopeia A supernova remnant is shown. Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion. It consists of a dead star, called a neutron star, and a surrounding shell of material that was blasted off as the star died.

    Panning outward, 'light echoes' create the illusion of motion in the clouds, as different areas of the material are lit up in succession by the light flash of the supernova. A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one. The result is an optical illusion, in which the dust appears to be flying outward at the speed of light.

    In reality, the clouds are stationary, at least in the brief time over which these observations were taken. The inclination of the clouds cause some light echoes to appear to expand away from the supernova remnant, while others move towards it or boil in many directions with seeming turbulence.

  16. The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Schady, P.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bottacini, E.; Bouvier, A.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Gehrels, N.; Guirec, S.; Hays, E.; McEnery, J. E.; Perkins, J. S.; Scargle, J. D.; Troja, E.

    2012-01-01

    The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL isimportant to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. Here, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z approx. 1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to ultraviolet frequencies and allowed us to measure the EBL flux density in this frequency band.

  17. Hypothermic anesthesia attenuates postoperative proteolysis.

    PubMed Central

    Johnson, D J; Brooks, D C; Pressler, V M; Hulton, N R; Colpoys, M F; Smith, R J; Wilmore, D W

    1986-01-01

    The catabolic response that commonly occurs after major operation is characterized by net skeletal muscle proteolysis and accelerated nitrogen excretion. This response was absent in patients undergoing cardiac surgical procedures associated with the combination of cardiopulmonary bypass, narcotic anesthesia, neuromuscular blockade, and hypothermia. Forearm nitrogen release was 422 +/- 492 nmol/100 ml X min on the first postoperative day, approximately 25% of preoperative values (1677 +/- 411, p less than 0.05). Nitrogen excretion and the degree of negative nitrogen balance were comparable to levels observed in nonstressed, fasting subjects. The potential role of hypothermia, high-dose fentanyl anesthesia, and neuromuscular blockade in modifying the catabolic response to laparotomy and retroperitoneal dissection was further evaluated in animal studies. Six hours after operation, amino acid nitrogen release from the hindquarter was 84% less than control values (p less than 0.05). Nitrogen excretion and urea production were also reduced compared to normothermic controls. It is concluded that the combination of hypothermia, narcotic anesthesia, and neuromuscular blockade attenuates the catabolic response to injury and thus may be useful in the care of critically ill surgical patients. PMID:3767477

  18. Nitrogen narcosis attenuates shivering thermogenesis.

    PubMed

    Mekjavić, I B; Savić, S A; Eiken, O

    1995-06-01

    Thermoregulatory responses of eight healthy subjects (six men and two women) were compared when they were head-out immersed in 15 degrees C water at both 1 and 6 ATA. Both trials were conducted in a hyperbaric chamber. During the immersions, esophageal temperature (T(es)) and skin temperature at two sites (chest and calf) were recorded at minute intervals. Oxygen uptake was determined at 5-min intervals with the Douglas bag method. The order of the two trials was alternated. The rate of T(es) cooling was greater during the 6-ATA trial [2.1 +/- 0.5 degrees C/h (SE)] than during the 1-ATA trial (1.3 +/- 0.5 degrees C/h; P < 0.01). Despite the greater rate of core cooling, and presumably a greater thermal drive for shivering, the oxygen uptake response for a similar decrement in T(es) was lower during exposure to 6 than to 1 ATA (P < 0.05). Also, for similar displacement in T(es), the subjects perceived the immersions at 6 ATA to be less cold than those at 1 ATA (P < 0.05). It is concluded that the development of hypothermia in compressed-air divers may be due, in large part, to the attenuation of heat production and cold perception. Most likely, the observed effects on the autonomic responses and thermal perception are due to an inhibitory action of hyperbaric nitrogen on central neural structures involved in temperature regulation.

  19. Resonant attenuation of surface acoustic waves by a disordered monolayer of microspheres

    NASA Astrophysics Data System (ADS)

    Eliason, J. K.; Vega-Flick, A.; Hiraiwa, M.; Khanolkar, A.; Gan, T.; Boechler, N.; Fang, N.; Nelson, K. A.; Maznev, A. A.

    2016-02-01

    Attenuation of surface acoustic waves (SAWs) by a disordered monolayer of polystyrene microspheres is investigated. Surface acoustic wave packets are generated by a pair of crossed laser pulses in a glass substrate coated with a thin aluminum film and detected via the diffraction of a probe laser beam. When a 170 μm-wide strip of micron-sized spheres is placed on the substrate between the excitation and detection spots, strong resonant attenuation of SAWs near 240 MHz is observed. The attenuation is caused by the interaction of SAWs with a contact resonance of the microspheres, as confirmed by acoustic dispersion measurements on the microsphere-coated area. Frequency-selective attenuation of SAWs by such a locally resonant metamaterial may lead to reconfigurable SAW devices and sensors, which can be easily manufactured via self-assembly techniques.

  20. Seismic-wave attenuation associated with crustal faults in the new madrid seismic zone.

    PubMed

    Hamilton, R M; Mooney, W D

    1990-04-20

    The attenuation of upper crustal seismic waves that are refracted with a velocity of about 6 kilometers per second varies greatly among profiles in the area of the New Madrid seismic zone in the central Mississippi Valley. The waves that have the strongest attenuation pass through the seismic trend along the axis of the Reelfoot rift in the area of the Blytheville arch. Defocusing of the waves in a low-velocity zone and/or seismic scattering and absorption could cause the attenuation; these effects are most likely associated with the highly deformed rocks along the arch. Consequently, strong seismic-wave attenuation may be a useful criterion for identifying seismogenic fault zones.

  1. Preparation and electromagnetic waves attenuation performances of infrared-interfering composite smog

    NASA Astrophysics Data System (ADS)

    Liu, Xiang-cui; Liu, Qing-hai; Dai, Meng-yan; Shi, Wei-dong; Fang, Guo-feng; Zhang, Tong

    2016-10-01

    The infrared-interfering composite smog material is prepared by a heating and agitating device in aqueous solutions and then sprayed into a cloud chamber for six minutes to form smog using gas-water mixing spray system. The attenuation performances of the smog to visible light, 1.06μm laser, 3-5μm infrared and 8-14μm infrared are evaluated, and compared with those of other testing materials. The results show that the sprayed smog have the best attenuation performances and the longest interfering time to visible light, 1.06μm laser, 3-5μm infrared and 8-14μm infrared. Therefore, the infrared-interfering composite smog material in the form of aqueous solution is the new smoke obscurant materials that are environment-friendly and possess broad application prospects in some aspects such as visible light, laser and infrared countermeasures.

  2. Fast Light-Sheet Scanner

    NASA Technical Reports Server (NTRS)

    Hunter, William W., Jr.; Humphreys, William M., Jr.; Bartram, Scott M.

    1995-01-01

    Optomechanical apparatus maintains sheet of pulsed laser light perpendicular to reference axis while causing sheet of light to translate in oscillatory fashion along reference axis. Produces illumination for laser velocimeter in which submicrometer particles entrained in flow illuminated and imaged in parallel planes displaced from each other in rapid succession. Selected frequency of oscillation range upward from tens of hertz. Rotating window continuously shifts sheet of light laterally while maintaining sheet parallel to same plane.

  3. EDITORIAL: Slow light Slow light

    NASA Astrophysics Data System (ADS)

    Boyd, Robert; Hess, Ortwin; Denz, Cornelia; Paspalakis, Emmanuel

    2010-10-01

    Research into slow light began theoretically in 1880 with the paper [1] of H A Lorentz, who is best known for his work on relativity and the speed of light. Experimental work started some 60 years later with the work of S L McCall and E L Hahn [2] who explored non-linear self-induced transparency in ruby. This field of research has burgeoned in the last 10 years, starting with the work of L Vestergaard Hau and coworkers on slow light via electromagnetically induced transparency in a Bose-Einstein condensate [3]. Many groups are now able to slow light down to a few metres per second or even stop the motion of light entirely [4]. Today, slow light - or more often `slow and fast light' - has become its own vibrant field with a strongly increasing number of publications. In broad scope, slow light research can be categorized in terms of the sort of physical mechanism used to slow down the light. One sort of slow light makes use of material dispersion. This dispersion can be the natural dispersion of the ordinary refractive index or can be the frequency dependence of some nonlinear optical process, such as electromagnetically induced transparency, coherent population oscillations, stimulated light scattering, or four-wave mixing processes. The second sort of slow light makes use of the wavelength dependence of artificially structured materials, such as photonic crystals, optical waveguides, and collections of microresonators. Material systems in which slow light has been observed include metal vapours, rare-earth-doped materials, Raman and Brillioun gain media, photonic crystals, microresonators and, more recently, metamaterials. A common feature of all of these schemes is the presence of a sharp single resonance or multiple resonances produced by an atomic transition, a resonance in a photonic structure, or in a nonlinear optical process. Current applications of slow light include a series of attractive topics in optical information processing, such as optical data

  4. Attenuation of landfill leachate by clay liner materials in laboratory columns: 2. Behaviour of inorganic contaminants.

    PubMed

    Thornton, S F; Lerner, D N; Tellam, J H

    2001-02-01

    The chemical attenuation of inorganic contaminants in methanogenic landfill leachate, spiked with heavy metals (Cd, Cd, Ni and Zn), by two UK clay liner materials was compared in laboratory columns over 15 months. Ammonium was attenuated by ion-exchange but this attenuation was finite and when exhausted, NH4 passed through the liners at concentrations found in the leachate. The breakthrough behaviour of NH4 could be described by a simple distribution coefficient. Heavy metals were attenuated by sorption and precipitation of metal sulphide and carbonate compounds near the top of the liner. Adequate SO4 and CaCO3 in the liner is necessary to ensure the long term retention of heavy metals, and pH buffering agents added to stabilise reactive metal fractions should be admixed with the liner. Some metals may not be chemically attenuated by clay liners due to the formation of stable complexes with organic and/or colloidal fractions in leachate. Flushing of the liners with oxygenated water after leachate caused mobilisation of attenuated contaminants. Sorbed NH4 was released by the liners but groundwater loadings were manageable. Re-oxidation of metal sulphides under these conditions resulted in the release of heavy metals from the liners when the pH buffering capacity was poor. Contaminant attenuation by the clay liners was similar and the attenuation of NH4 and heavy metals could be predicted from the geochemical properties of the liner using simple tests. A conceptual model of clay liner performance is presented. Chemical attenuation of inorganic pollutants can be included in containment liner design to produce a dual reactive-passive barrier for landfills.

  5. Measurement of breast-tissue x-ray attenuation by spectral mammography: solid lesions

    NASA Astrophysics Data System (ADS)

    Fredenberg, Erik; Kilburn-Toppin, Fleur; Willsher, Paula; Moa, Elin; Danielsson, Mats; Dance, David R.; Young, Kenneth C.; Wallis, Matthew G.

    2016-04-01

    Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. For instance, techniques to distinguish between cysts and solid tumours at mammography screening would be highly desirable to reduce recalls, but the development requires knowledge of the x-ray attenuation for cysts and tumours. We have previously measured the attenuation of cyst fluid using photon-counting spectral mammography. Data on x-ray attenuation for solid breast lesions are available in the literature, but cover a relatively wide range, likely caused by natural spread between samples, random measurement errors, and different experimental conditions. In this study, we have adapted a previously developed spectral method to measure the linear attenuation of solid breast lesions. A total of 56 malignant and 5 benign lesions were included in the study. The samples were placed in a holder that allowed for thickness measurement. Spectral (energy-resolved) images of the samples were acquired and the image signal was mapped to equivalent thicknesses of two known reference materials, which can be used to derive the x-ray attenuation as a function of energy. The spread in equivalent material thicknesses was relatively large between samples, which is likely to be caused mainly by natural variation and only to a minor extent by random measurement errors and sample inhomogeneity. No significant difference in attenuation was found between benign and malignant solid lesions. The separation between cyst-fluid and tumour attenuation was, however, significant, which suggests it may be possible to distinguish cystic from solid breast lesions, and the results lay the groundwork for a clinical trial. In addition, the study adds a relatively large sample set to the published data and may contribute to a reduction in the overall uncertainty in the literature.

  6. Attenuation of tumor necrosis factor-induced endothelial cell cytotoxicity and neutrophil chemiluminescence

    SciTech Connect

    Zheng, H.; Crowley, J.J.; Chan, J.C.; Hoffmann, H.; Hatherill, J.R.; Ishizaka, A.; Raffin, T.A. )

    1990-11-01

    Our laboratory has previously shown that the administration of tumor necrosis factor (TNF), a cytokine produced by activated mononuclear cells, to guinea pigs produces a syndrome similar to gram-negative sepsis or ARDS. Pentoxifylline (PTX), a methylxanthine, protects against TNF-induced and sepsis-induced acute lung injury in vivo. We now report on in vitro cellular studies of PMN-mediated cellular injury and its attenuation. We studied TNF-induced bovine pulmonary artery endothelial cell (EC) cytotoxicity both with and without PMN. A 51Cr release assay was used to measure EC damage. Further, we investigated PMN function in response to TNF by measuring chemiluminescence. Agents that attenuate EC damage and PMN activation were evaluated in the above assays. Results revealed that TNF causes EC injury (p less than 0.05) and PMN increase TNF-induced EC injury. Furthermore, PTX, aminophylline (AMPH), caffeine, and forskolin attenuate TNF-induced EC cytotoxicity only in the presence of PMN (p less than 0.05). Of interest, dibutyryl cAMP (DBcAMP) protects EC from TNF-induced injury both with and without PMN. Agents that may increase cAMP levels in PMN (PTX, DBcAMP, forskolin, isobutyl methylxanthine, and terbutaline) significantly attenuate TNF-induced PMN chemiluminescence (p less than 0.05). We conclude that TNF causes EC damage and PMN increase this damage. Furthermore, PTX, AMPH, caffeine, and forskolin can attenuate TNF-induced EC injury in the presence of PMN, whereas DBcAMP attenuates TNF-induced EC injury with and without PMN. In addition, agents that may increase intracellular cAMP levels in PMN can attenuate TNF-induced PMN chemiluminescence. Thus, these agents likely attenuate TNF-induced PMN-mediated EC injury through their inhibitory effects on PMN.

  7. Plasmodium yoelii: induction of attenuated mutants by irradiation

    SciTech Connect

    Waki, S.; Yonome, I.; Suzuki, M.

    1986-12-01

    When erythrocytic forms of Plasmodium yoelii nigeriensis, which is invariably fatal in mice, were exposed to X rays, the dose to reduce surviving parasites to one millionth was 100 gray (10 Krad). A suspension of 5 X 10(6) per ml of parasitized erythrocyte was irradiated at 100 gray, and 0.2 ml aliquots were inoculated into 22 mice. Eleven mice showed patent parasitemia, and in these the growth curves were less steep than that found in nonirradiated parasites. The infections of 8 mice of the 11 were self-resolving, and the attenuated feature of the parasites maintained following a limited number of blood passages. The parasites were slowly growing even in nude mice and cause self-resolving infections in intact mice. BALB/c mice immunized with the attenuated parasites were protected against subsequent challenge infections with the original virulent erythrocytic and sporogonic forms. These findings indicate that attenuated mutants of malaria parasites can be readily induced by this method.

  8. A study of the acoustical radiation force considering attenuation

    NASA Astrophysics Data System (ADS)

    Wu, RongRong; Liu, XiaoZhou; Gong, XiuFen

    2013-07-01

    Acoustical tweezer is a primary application of the radiation force of a sound field. When an ultrasound focused beam passes through a micro-particle, like a cell or living biological specimens, the particle will be manipulated accurately without physical contact and invasion, due to the three-dimensional acoustical trapping force. Based on the Ray acoustics approach in the Mie regime, this work discusses the effects on the particle caused by Gaussian focused ultrasound, studies the acoustical trapping force of spherical Mie particles by ultrasound in any position, and analyzes the numerical calculation on the two-dimensional acoustical radiation force. This article also analyzes the conditions for the acoustical trapping phenomenon, and discusses the impact of the initial position and size of the particle on the magnitude of the acoustical radiation force. Furthermore, this paper considers the ultrasonic attenuation in a particle in the case of two-dimension, studies the attenuation's effects on the acoustical trapping force, and amends the calculation to the ordinary case with attenuation.

  9. High Attenuation Rate for Shallow, Small Earthquakes in Japan

    NASA Astrophysics Data System (ADS)

    Si, Hongjun; Koketsu, Kazuki; Miyake, Hiroe

    2017-03-01

    We compared the attenuation characteristics of peak ground accelerations (PGAs) and velocities (PGVs) of strong motion from shallow, small earthquakes that occurred in Japan with those predicted by the equations of Si and Midorikawa (J Struct Constr Eng 523:63-70, 1999). The observed PGAs and PGVs at stations far from the seismic source decayed more rapidly than the predicted ones. The same tendencies have been reported for deep, moderate, and large earthquakes, but not for shallow, moderate, and large earthquakes. This indicates that the peak values of ground motion from shallow, small earthquakes attenuate more steeply than those from shallow, moderate or large earthquakes. To investigate the reason for this difference, we numerically simulated strong ground motion for point sources of M w 4 and 6 earthquakes using a 2D finite difference method. The analyses of the synthetic waveforms suggested that the above differences are caused by surface waves, which are predominant at stations far from the seismic source for shallow, moderate earthquakes but not for shallow, small earthquakes. Thus, although loss due to reflection at the boundaries of the discontinuous Earth structure occurs in all shallow earthquakes, the apparent attenuation rate for a moderate or large earthquake is essentially the same as that of body waves propagating in a homogeneous medium due to the dominance of surface waves.

  10. Clinical evaluation strategies for a live attenuated tetravalent dengue vaccine.

    PubMed

    Precioso, Alexander Roberto; Palacios, Ricardo; Thomé, Beatriz; Mondini, Gabriella; Braga, Patrícia; Kalil, Jorge

    2015-12-10

    Butantan Institute is a public Brazilian biomedical research-manufacturer center affiliated to the São Paulo State Secretary of Health. Currently, Butantan is one of the main public producers of vaccines, antivenoms, and antitoxins in Latin America. The partnership between Butantan and the National Institutes of Health (NIH) of the United Sates has been one of the longest and most successful partnerships in the development and manufacturing of new vaccines. Recently, Butantan Institute has developed and manufactured a lyophilized tetravalent live attenuated dengue vaccine with the four dengue viruses attenuated and licensed from the Laboratory of Infectious Diseases at The National Institutes of Allergy and Infectious Diseases (LID/NIAID/NIH). The objective of this paper is to describe the clinical evaluation strategies of a live attenuated tetravalent dengue vaccine (Butantan-DV) developed and manufactured by Butantan Institute. These clinical strategies will be used to evaluate the Butantan-DV Phase III trial to support the Butantan-DV licensure for protection against any symptomatic dengue caused by any serotype in people aged 2 to 59 years.

  11. Thermal attenuation and dispersion of sound in a periodic emulsion

    NASA Astrophysics Data System (ADS)

    Fukumoto, Yasuhide; Izuyama, Takeo

    1992-10-01

    We investigate the attenuation and dispersion of sound waves in suspensions and emulsions caused by the thermal-transport process. They combine to constitute the effective compressibility of the system. We begin with an attempt to justify the Isakovich formula for calculating the effective compressibility. The formula is then rewritten in terms of the interfacial heat flux. Isakovich's analysis is simply an independent-particle approximation. It is the purpose of this paper to consider the effect of interparticle interactions. The effective compressibility is calculated for an array of spherical particles or droplets centered at the points of a periodic lattice, immersed in a fluid of different species. Ewald's method of fast-convergent lattice sums in electrostatics is extended to a technique for the heat-conduction problem in a periodic emulsion. The computation for cubic lattices reveals that the interparticle interactions act to reduce, in the lower-frequency range, both the attenuation coefficient and the departure of the sound velocity from its high-frequency limit. The striking feature is that a drastic change in attenuation occurs when the thermal conductivity of the particle is substantially larger than that of the ambient fluid.

  12. Natural attenuation general data guide. Final report

    SciTech Connect

    Kram, M.L.; Goetz, F.

    1999-02-01

    This guide is a decision-making tool to help remedial project managers (RPMs) determine whether natural attenuation can be used as a remedial option at contaminant release sites. Data requirements and methodology to evaluate the potential for using natural attenuation are presented. For sites where the natural attenuation remedial option is implemented, tables of commonly measured parameters, general data collection rationale, and interpretation guidance are included. This format allows the RPM to recognize data gaps, interpret data, construct a conceptual site model, and develop a sampling and analysis plan for evaluation and monitoring purposes.

  13. Seasonal variability of light availability and utilization in the Sargasso Sea

    NASA Technical Reports Server (NTRS)

    Siegel, David A.; Michaels, Anthony F.; Sorensen, Jens C.; O'Brein, Margaret C.; Hammer, Melodie A.

    1995-01-01

    A 2 year time series of optical, biogeochemical, and physical parameters, taken near the island of Bermuda, is used to evaluate the sources of temporal variability in light avaliability and utilization in the Sargasso Sea. Integrated assessments of light availability are made by examining the depth of constant percent incident photosynthetically available radiation (% PAR) isolumes. To first order, changes in the depth %PAR isolumes were caused by physical processes: deep convection mixing in the winter which led to the spring bloom and concurrent shallowing of %PAR depths and the occurrence of anomalous thermohaline water masses during the summer and fall seasons. Spectral light availability variations are assessed using determinations of diffuse attenuation coefficient spectra which illustrates a significant seasonal cycle in colored detrital particulate and/or dissolved materials that is unrelated to changes in chlorophyll pigment concentrations. Temporal variations in the photosynthetic light utilization index Psi are used to assess vertically intergrated light utilization variations. Values of Psi are highly variable and show no apparent seasonal pattern which indicates that Psi is not simply a 'biogeochemical constant.' Determinations of in situ primary production rates and daily mean PAR fluxes are used to diagnose the relative role of light limitation in determining vertically integrated rates of primary production integral PP. The mean depth of the light-saturated zone (the vertical region where the daily mean PAR flux was greater than or equal to the saturation irradiance) is only approximately 40 m, although more than one half of interal PP occurred within this zone. Production model results illustrate that accurate predictions of integral PP are dependent upon rates of light-saturated production rather than upon indices of light limitation. It seems unlikely that significant improvements in simple primary production models will come from the

  14. Seasonal variability of light availability and utilization in the Sargasso Sea

    NASA Astrophysics Data System (ADS)

    Siegel, David A.; Michaels, Anthony F.; Sorensen, Jens C.; O'Brien, Margaret C.; Hammer, Melodie A.

    1995-05-01

    A 2 year time series of optical, biogeochemical, and physical parameters, taken near the island of Bermuda, is used to evaluate the sources of temporal variability in light availability and utilization in the Sargasso Sea. Integrated assessments of light availability are made by examining the depth of constant percent incident photosynthetically available radiation (%PAR) isolumes. To first order, changes in the depth of %PAR isolumes were caused by physical processes: deep convective mixing in the winter which led to the spring bloom and concurrent shallowing of %PAR depths and the occurrence of anomalous thermohaline water masses during the summer and fall seasons. Spectral light availability variations are assessed using determinations of diffuse attenuation coefficient spectra which illustrate a significant seasonal cycle in colored detrital paniculate and/or dissolved materials that is unrelated to changes in chlorophyll pigment concentrations. Temporal variations in the photosynthetic light utilization index Ψ are used to assess vertically integrated light utilization variations. Values of Ψ are highly variable and show no apparent seasonal pattern which indicates that Ψ is not simply a "biogeochemical constant" Determinations of in situ primary production rates and daily mean PAR fluxes are used to diagnose the relative role of light limitation in determining vertically integrated rates of primary production ∫PP. The mean depth of the light-saturated zone (the vertical region where the daily mean PAR flux was greater than or equal to the saturation irradiance Ik) is only ˜40 m, although more than one half of ∫PP occurred within this zone. Production model results illustrate that accurate predictions of ∫PP are dependent upon rates of light-saturated production rather than upon indices of light limitation. It seems unlikely that significant improvements in simple primary production models will come from the partitioning of the Earth's seas into

  15. Metallic attenuated total reflection infrared hollow fibers for robust optical transmission systems

    NASA Astrophysics Data System (ADS)

    Jing, Chengbin; Guo, Hong; Hu, Zhigao; Yang, Pingxiong; Chu, Junhao; Liu, Aiyun; Shi, Yiwei

    2014-07-01

    A durable metallic attenuated total reflection (ATR) hollow fiber (bore size: 1.45 mm, wall thickness: 50 μm) was designed and fabricated based on a nickel capillary tube and hexagonal germanium dioxide (GeO2). The anomalous dispersion of the hexagonal GeO2 layer grown inside a nickel tube achieves low-loss light transmission at two peak-power wavelengths for CO2 laser devices (10.2 and 10.6 μm). An 11-28 W, 10.2 or 10.6 μm CO2 laser power was steadily delivered via a fiber elastically bent from 0° to 90° (radius: 45 cm) for over 40 min (transmission loss: 0.22 to 4.2 dB/m). Theoretically fitting the measured temperatures showed that front-end clipping caused greater thermal loading than the distributed mode absorption. The maximum external temperature of a nickel ATR fiber is much lower than that of a silica glass ATR fiber owing to their different heat dissipation abilities. The HE11 mode purity of the output beam profiles decreased from 90.3% to 44.7% as the bending angle increased from 0° to 90°. Large core sizes and wall roughnesses (scattering loss 0.04 dB/m) contributed to mode mixing and excess losses that were above the value predicted by the classical Marcatili and Schmeltzer equation (0.024-0.037 dB/m).

  16. Seagrasses, Dredging and Light in Laguna Madre, Texas, U.S.A.

    NASA Astrophysics Data System (ADS)

    Onuf, Christopher P.

    1994-07-01

    Light reduction resulting from maintenance dredging was the suspected cause of large-scale loss of seagrass cover in deep parts of Laguna Madre between surveys conducted in 1965 and 1974. Additional changes to 1988, together with an analysis of dredging frequency and intensity for different parts of the laguna, were consistent with this interpretation. Intensive monitoring of the underwater light regime and compilation of detailed environmental data for 3 months before and 15 months after a dredging project in 1988 revealed reduced light attributable to dredging in four of eight subdivisions of the study area, including the most extensive seagrass meadow in the study area. Dredging effects were strongest close to disposal areas used during this project but still were detectable on transects >1·2 km from the nearest dredge disposal area. In the subdivision of the study area where most of the dredge disposal occurred, light attenuation was increased throughout the 15 months of observation after dredging. In the seagrass meadow and the transition zone at the outer edge of the meadow, effects were evident up to 10 months after dredging. Resuspension and dispersion events caused by wind-generated waves are responsible for the propagation of dredge-related turbidity over space and time in this system.

  17. Mt. Kelud haze removal using color attenuation prior

    NASA Astrophysics Data System (ADS)

    Fresy, N.; Yuniarno, Eko M.; Supeno, M. S. N.; Hariadi, M.

    2017-03-01

    Kelud crater observation using closed-circuit television (CCTV) has not been used as the main guide in the world of volcanology. This is caused by observations manually by volcanologist who is not certain and depends on their ability and experience. In practice, there is still obstacles haze in the image taken from CCTV record. This paper present color attenuation prior method to eliminate haze on the digital image. The results obtained showed that the selected method is capable of eliminating sparse haze and moderate haze but not dense haze.

  18. Light Learning.

    ERIC Educational Resources Information Center

    Cutshall, Sandy

    2002-01-01

    Describes a career and technical education program on photonics, the study, research, and development of equipment and concepts used in the transmission of information through light, including fiber optics and experimental laser technologies. (JOW)

  19. Light touch

    NASA Astrophysics Data System (ADS)

    Baskaran, G.

    2014-09-01

    Light sustains life. It enlightens. Over centuries it has illuminated our path to understanding our physical universe. Efforts to understand black body radiation gave birth to quantum mechanics. Same light revealed the secret of space-time through special theory of relativity. Light is a visible manifestation of quantum mechanics. Laser is a macroscopic quantum state available even at room temperatures. Following a general introduction I discuss quantum coherence, common in macroscopic quantum phenomena such as laser, superfluidity, superconductivity and superradiance. I raise a question, can we transfer macroscopic quantum coherence from a laser to a metal and induce superconductivity at room temperatures?. In certain recent experiments, femtosecond laser light is claimed to create transient superconductivity at room temperatures, in the pseudo gap metallic phase of certain cuprates. This has been discussed in terms of superradiant superconductivity, a new quantum coherence transfer mechanism we have suggested recently.

  20. The 3D Attenuation Structure of Deception Island (Antarctica)

    NASA Astrophysics Data System (ADS)

    Prudencio, J.; De Siena, L.; Ibáñez, J. M.; Del Pezzo, E.; García-Yeguas, A.; Díaz-Moreno, A.

    2015-05-01

    The seismic and volcanological structure of Deception Island (Antarctica) is an intense focus topic in Volcano Geophysics. The interpretations given by scientists on the origin, nature, and location of the structures buried under the island strongly diverge. We present a high-resolution 3D P-wave attenuation tomography model obtained by using the coda normalization method on 20,293 high-quality waveforms produced by active sources. The checkerboard and synthetic anomaly tests guarantee the reproduction of the input anomalies under the island down to a depth of 4 km. The results, once compared with our current knowledge on the geological, geochemical, and geophysical structure of the region, depict Deception as a piecemeal caldera structure coming out of the Bransfield Trough. High-attenuation anomalies contouring the northeastern emerged caldera rim correlate with the locations of sediments. In our interpretation, the main attenuation contrast, which appears under the collapsed southeastern caldera rim, is related to the deeper feeding systems. A unique P-wave high-attenuation spherical-like anomaly in the inner bay extends between depths of 1 and 3 km. The northern contour of the anomaly coincides with the calderic rim both at 1 and 2 km, while smaller anomalies connect it with deeper structures below 3 km, dipping toward the Bransfield Trough. In our interpretation, the large upper anomaly is caused by a high-temperature shallow (1-3 km deep) geothermal system, located beneath the sediment-filled bay in the collapsed blocks and heated by smaller, deeper contributions of molten materials (magma) rising from southeast.

  1. Acetazolamide Attenuates Lithium-Induced Nephrogenic Diabetes Insipidus.

    PubMed

    de Groot, Theun; Sinke, Anne P; Kortenoeven, Marleen L A; Alsady, Mohammad; Baumgarten, Ruben; Devuyst, Olivier; Loffing, Johannes; Wetzels, Jack F; Deen, Peter M T

    2016-07-01

    To reduce lithium-induced nephrogenic diabetes insipidus (lithium-NDI), patients with bipolar disorder are treated with thiazide and amiloride, which are thought to induce antidiuresis by a compensatory increase in prourine uptake in proximal tubules. However, thiazides induced antidiuresis and alkalinized the urine in lithium-NDI mice lacking the sodium-chloride cotransporter, suggesting that inhibition of carbonic anhydrases (CAs) confers the beneficial thiazide effect. Therefore, we tested the effect of the CA-specific blocker acetazolamide in lithium-NDI. In collecting duct (mpkCCD) cells, acetazolamide reduced the cellular lithium content and attenuated lithium-induced downregulation of aquaporin-2 through a mechanism different from that of amiloride. Treatment of lithium-NDI mice with acetazolamide or thiazide/amiloride induced similar antidiuresis and increased urine osmolality and aquaporin-2 abundance. Thiazide/amiloride-treated mice showed hyponatremia, hyperkalemia, hypercalcemia, metabolic acidosis, and increased serum lithium concentrations, adverse effects previously observed in patients but not in acetazolamide-treated mice in this study. Furthermore, acetazolamide treatment reduced inulin clearance and cortical expression of sodium/hydrogen exchanger 3 and attenuated the increased expression of urinary PGE2 observed in lithium-NDI mice. These results show that the antidiuresis with acetazolamide was partially caused by a tubular-glomerular feedback response and reduced GFR. The tubular-glomerular feedback response and/or direct effect on collecting duct principal or intercalated cells may underlie the reduced urinary PGE2 levels with acetazolamide, thereby contributing to the attenuation of lithium-NDI. In conclusion, CA activity contributes to lithium-NDI development, and acetazolamide attenuates lithium-NDI development in mice similar to thiazide/amiloride but with fewer adverse effects.

  2. Light's twist

    PubMed Central

    Padgett, Miles

    2014-01-01

    That light travels in straight lines is a statement of the obvious. However, the energy and momentum flow within light beams can twist to form vortices such as eddies in a stream. These twists carry angular momentum, which can make microscopic objects spin, be used to encode extra information in communication systems, enable the design of novel imaging systems and allow new tests of quantum mechanics. PMID:25484612

  3. Attenuation of external Bremsstrahlung in metallic absorbers

    SciTech Connect

    Dhaliwal, A.S.; Powar, M.S.; Singh, M. )

    1990-12-01

    In this paper attenuation of bremsstrahlung from {sup 147}Pm and {sup 170}Tm beta emitters has been studied in aluminum, copper, tin, and lead metallic absorbers. Bremsstrahlung spectra and mass attenuation coefficients for monoenergetic gamma rays are used to calculate theoretical attenuation curves. Magnetic deflection and beta stopping techniques are used to measure the integral bremsstrahlung intensities above 30 keV in different target thicknesses. Comparison of measured and calculated attenuation curves shows a good agreement for various absorbers, thus providing a test of this technique, which may be useful in understanding bremsstrahlung intensity buildup and in the design of optimum shielding for bremsstrahlung sources. It is found that the absorption of bremsstrahlung in metallic absorbers does not obey an exponential law and that absorbers act as energy filters.

  4. Evolution of Natural Attenuation Evaluation Protocols

    EPA Science Inventory

    Traditionally the evaluation of the efficacy of natural attenuation was based on changes in contaminant concentrations and mass reduction. Statistical tools and models such as Bioscreen provided evaluation protocols which now are being approached via other vehicles including m...

  5. Attenuated retroreflectors for electronic distance measurement

    NASA Astrophysics Data System (ADS)

    Parker, David H.; Goldman, Michael A.; Radcliff, Bill; Shelton, John W.

    Methods are described for attenuating solid glass and hollow retroreflectors, without introducing optical path length modifications, for electronic distance measurement. Construction of a prototype novel-design hollow retroreflector is described.

  6. Electron Effective-Attenuation-Length Database

    National Institute of Standards and Technology Data Gateway

    SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge)   This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).

  7. Ultrasonic Attenuation in Normal and Superconducting Indium.

    DTIC Science & Technology

    1980-05-22

    Bardeen et al, Phys. Rev. 108, 1175), there is an additional source of attenuation. This DD I° 7 1473 EDITION OF NOV S E UNCLASSIFIED SECURITY...electronic attenuation described quantitatively by the BCS theory of super- conductivity ( Bardeen et al., Phys. Rev. 108, 1175), there is an additional source...single crystal of C lead at 26.5 MHz is shown in Figure 1. This phenomenon was first explained quantitatively by Bardeen ,Cooper, and Schrieffer (1957

  8. Ursodeoxycholic acid attenuates colonic epithelial secretory function

    PubMed Central

    Kelly, Orlaith B; Mroz, Magdalena S; Ward, Joseph B J; Colliva, Carolina; Scharl, Michael; Pellicciari, Roberto; Gilmer, John F; Fallon, Padraic G; Hofmann, Alan F; Roda, Aldo; Murray, Frank E; Keely, Stephen J

    2013-01-01

    Dihydroxy bile acids, such as chenodeoxycholic acid (CDCA), are well known to promote colonic fluid and electrolyte secretion, thereby causing diarrhoea associated with bile acid malabsorption. However, CDCA is rapidly metabolised by colonic bacteria to ursodeoxycholic acid (UDCA), the effects of which on epithelial transport are poorly characterised. Here, we investigated the role of UDCA in the regulation of colonic epithelial secretion. Cl− secretion was measured across voltage-clamped monolayers of T84 cells and muscle-stripped sections of mouse or human colon. Cell surface biotinylation was used to assess abundance/surface expression of transport proteins. Acute (15 min) treatment of T84 cells with bilateral UDCA attenuated Cl− secretory responses to the Ca2+ and cAMP-dependent secretagogues carbachol (CCh) and forskolin (FSK) to 14.0 ± 3.8 and 40.2 ± 7.4% of controls, respectively (n= 18, P < 0.001). Investigation of the molecular targets involved revealed that UDCA acts by inhibiting Na+/K+-ATPase activity and basolateral K+ channel currents, without altering their cell surface expression. In contrast, intraperitoneal administration of UDCA (25 mg kg−1) to mice enhanced agonist-induced colonic secretory responses, an effect we hypothesised to be due to bacterial metabolism of UDCA to lithocholic acid (LCA). Accordingly, LCA (50–200 μm) enhanced agonist-induced secretory responses in vitro and a metabolically stable UDCA analogue, 6α-methyl-UDCA, exerted anti-secretory actions in vitro and in vivo. In conclusion, UDCA exerts direct anti-secretory actions on colonic epithelial cells and metabolically stable derivatives of the bile acid may offer a new approach for treating intestinal diseases associated with diarrhoea. PMID:23507881

  9. Sensory Attenuation for Jointly Produced Action Effects

    PubMed Central

    Loehr, Janeen D.

    2012-01-01

    Successful joint action often requires people to distinguish between their own and others’ contributions to a shared goal. One mechanism that is thought to underlie a self-other distinction is sensory attenuation, whereby the sensory consequences of one’s own actions are reduced compared to other sensory events. Previous research has shown that the auditory N1 event-related potential (ERP) response is reduced for self-generated compared to externally generated tones. The current study examined whether attenuation also occurs for jointly generated tones, which require two people to coordinate their actions to produce a single tone. ERP responses were measured when participants generated tones alone (tone onset immediately followed the participant’s button press) or with a partner (tone onset immediately followed the participant’s or the partner’s button press, whichever occurred second). N1 attenuation was smaller for jointly generated tones compared to self-generated tones. For jointly generated tones, greater delays between the participant’s and the partner’s button presses were associated with reduced attenuation; moreover, only trials in which there was no delay between the participant’s press and tone onset showed attenuation, whereas trials in which there were delays did not show attenuation. These findings indicate that people differentiate between their own and another person’s contributions to a joint action at the sensorimotor level, even when they must act together to produce a single, shared effect. PMID:23596429

  10. Using a Hexagonal Mirror for Varying Light Intensity in the Measurement of Small-Angle Variation

    PubMed Central

    Hsieh, Meng-Chang; Lin, Jiun-You; Chang, Chia-Ou

    2016-01-01

    Precision positioning and control are critical to industrial-use processing machines. In order to have components fabricated with excellent precision, the measurement of small-angle variations must be as accurate as possible. To achieve this goal, this study provides a new and simple optical mechanism by varying light intensity. A He-Ne laser beam was passed through an attenuator and into a beam splitter. The reflected light was used as an intensity reference for calibrating the measurement. The transmitted light as a test light entered the optical mechanism hexagonal mirror, the optical mechanism of which was created by us, and then it entered the power detector after four consecutive reflections inside the mirror. When the hexagonal mirror was rotated by a small angle, the laser beam was parallel shifted. Once the laser beam was shifted, the hitting area on the detector was changed; it might be partially outside the sensing zone and would cause the variation of detection intensity. This variation of light intensity can be employed to measure small-angle variations. The experimental results demonstrate the feasibility of this method. The resolution and sensitivity are 3 × 10−40 and 4 mW/° in the angular range of 0.6°, respectively, and 9.3 × 10−50 and 13 mW/° in the angular range of 0.25°. PMID:27537893

  11. Attenuation of an ultrasonic beam by suspended particles and range of acoustic flow meters in sewer networks.

    PubMed

    Larrarte, Frédérique; François, Pierre

    2012-01-01

    Ultrasonic flow meters are commonly used in wastewater management. Under certain circumstances, a reduction in the flow meter range may occur and cause significant error in the flow rate measurement. Attenuation due to suspended particles is one of the phenomena capable of reducing the flow meter range. The present paper examines attenuation resulting from re-suspended pond sediment over a wide range of concentration values. It appears that a formula established for sand suspensions provides a good estimate of ultrasound attenuation for these types of particles as well. Experiments conducted for wastewater under particle concentrations commonly encountered in sewer networks demonstrate that the attenuation by particles only contributes to a negligible extent towards intensity decay, in accordance with theoretical predictions. We also theoretically determine herein the operating conditions under which the range of an ultrasonic flow meter would be significantly reduced due to particle attenuation.

  12. Growth restriction of an experimental live attenuated human parainfluenza virus type 2 vaccine in human ciliated airway epithelium in vitro parallels attenuation in African green monkeys

    PubMed Central

    Schaap-Nutt, Anne; Scull, Margaret A.; Schmidt, Alexander C.; Murphy, Brian R.; Pickles, Raymond J.

    2010-01-01

    Human parainfluenza viruses (HPIVs) are common causes of severe pediatric respiratory viral disease. We characterized wild-type HPIV2 infection in an in vitro model of human airway epithelium (HAE) and found that the virus replicates to high titer, sheds apically, targets ciliated cells, and induces minimal cytopathology. Replication of an experimental, live attenuated HPIV2 vaccine strain, containing both temperature sensitive (ts) and non-ts attenuating mutations, was restricted >30-fold compared to rHPIV2-WT in HAE at 32°C and exhibited little productive replication at 37°C. This restriction paralleled attenuation in the upper and lower respiratory tract of African green monkeys, supporting the HAE model as an appropriate and convenient system for characterizing HPIV2 vaccine candidates. PMID:20139039

  13. Synchrotron light

    SciTech Connect

    Craievich, A. )

    1990-01-01

    Several developed countries such as the USA, URSS, England, France, Italy, Sweden and Japan have one or more of these synchrotron light facilities operating or under construction. Some developing countries have constructed (China) or are building (Taiwan, India, Korea, Brazil) synchrotron light facilities. The construction of the Brazilian synchrotron source began in June, 1987. After two years of activities, the injector linac for the electron storage ring is in its final stage of construction. These Proceedings contain the Invited Lectures presented at the Workshop by specialists working on synchrotron light applications and related instrumentation and by members of LNLS regarding technical details of the Brazilian project. The II Workshop Synchrotron Light: Applications and Related Instrumentation was dedicated to oral presentations about applications of synchrotron light, most of which were not covered during the I Workshop, organized by LNLS in 1988, and the Proceedings of which were published by World Scientific. The II Workshop included discussions on the application possibilities for the newly designed LNLS 1.15 GeV storage ring, and on the modifications which would eventually be necessary for the work-station and instrumentation projects currently in progress at LNLS and at various external user laboratories.

  14. High Intensity Lighting

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Nightime illumination is an important part of round-the-clock pre-launch preparations because NASA uses TV and film cameras to monitor each step of the preliminaries and at times to identify the cause of malfunction during countdown. Generating a one billion candlepower beam visible 50 miles away, the lamps developed by Duro-Test Corporation provide daylight quality light that eliminates color distortion in film and TV coverage. The lighting system was first used at Kennedy Space Center in 1968 for the launch of Apollo 8. Modified versions are available in wide range of applications, such as the battery of spotlights with colored filters that light up Niagara Falls, as well as the lamps used in the projectors for the Smithsonian's IMAX Theatre, indoor theatres with supersized screens and outdoor projection systems.

  15. Light echoes - Novae

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1988-01-01

    The sudden brilliance of a nova eruption will be reflected on surrounding dust grains to create a phantom nebula. Previous searches for these light echoes have used relatively short exposures with photograhic detectors. This paper reports on a search around eight recent novae with long exposures using a CCD camera. Despite an increase of sensitivity by over an order of magnitude, no light echoes were detected. It is found that the average grain density must be less than about 10 to the -9th per cu cm for distances from 0.1 pc to 1000 pc from the novae. The light echo around Nova Persei 1901 was caused by reflection off clouds with grain densities of several times 10 to the -9th per cu cm which are at distances between 0.1 pc and 10 pc. Echoes from dust in a circumstellar shell or ejected during a previous eruption will be effectively unobservable.

  16. Characterization of attenuated Theileria annulata vaccines from Spain and the Sudan.

    PubMed

    Gubbels, M J; Viseras, J; Habela, M A; Jongejan, F

    2000-01-01

    Theileriosis caused by Theileria annulata can be effectively prevented by vaccination with attenuated, cultured schizonts. Although these attenuated vaccines have been applied for a long time, not much is known about the fate of the vaccine strain in the field. Here, two experimental Spanish vaccine strains originating in Cádiz and Cáceres, and one Sudanese strain are studied to address the development of a carrier status and the infectivity for Hyalomma ticks. Moreover, the heterogeneity of the merozoite surface protein, Tams1, was analyzed in search for an attenuation marker. Using the sensitive reverse line blot (RLB) hybridization, the development of a low level carrier status was demonstrated in the Cáceres and Sudanese line vaccinated calves. Although no signal was detected in the Cádiz line vaccinated calves, seroconversion against the schizont stage was observed, as it was in all other calves. The experimental transmission of T. annulata by Hyalomma ticks to naïve calves was unsuccessful for all cell line inoculated calves. Tams1 heterogeneity indicated a clonal selection of parasites during the process of attenuation, but the Tams1 sequence itself has no connection with the attenuation status. In conclusion, a carrier status develops in attenuated schizont culture vaccinated calves, but is not infective for Hyalomma ticks. Based on these data, the risk for spread of the vaccine strains in the field may be very low.

  17. Study of transmission line attenuation in broad band millimeter wave frequency range

    SciTech Connect

    Pandya, Hitesh Kumar B.; Austin, M. E.; Ellis, R. F.

    2013-10-15

    Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

  18. Strong Lg-wave attenuation in the Middle East continental collision orogenic belt

    NASA Astrophysics Data System (ADS)

    Zhao, Lian-Feng; Xie, Xiao-Bi

    2016-04-01

    Using Lg-wave Q tomography, we construct a broadband crustal attenuation model for the Middle East. The QLg images reveal a relationship between attenuation and geological structures. Strong attenuation is found in the continental collision orogenic belt that extends from the Turkish and Iranian plateau to the Pamir plateau. We investigate the frequency dependence of QLg in different geologic formations. The results illustrate that QLg values generally increase with increasing frequency but exhibit complex relationships both with frequency and between regions. An average QLg value between 0.2 and 2.0 Hz, QLg (0.2-2.0 Hz), may be a critical index for crustal attenuation and is used to infer the regional geology. Low-QLg anomalies are present in the eastern Turkish plateau and correlate well with low Pn-velocities and Cenozoic volcanic activity, thus indicating possible partial melting within the crust in this region. Very strong attenuation is also observed in central Iran, the Afghanistan block, and the southern Caspian Sea. This in line with the previously observed high crustal temperature, high-conductivity layers, and thick marine sediments in these areas, suggests the high Lg attenuation is caused by abnormally high tectonic and thermal activities.

  19. Light extraction by Lambertian sources from light emitting diodes

    NASA Astrophysics Data System (ADS)

    Nagel, James R.

    2013-03-01

    Internal back-and-forth propagation of photons within a light emitting diode (LED) will naturally tend towards a Lambertian intensity profile when surface texturing is sufficiently rough. Novel designs in light extraction efficiency (LEE) can therefore benefit by optimizing under this expectation. This paper develops a framework for calculating LEE from a planar LED structure with textured surface features under the assumption of Lambertian intensity within the substrate. The method can estimate the total LEE value when given a substrate width w, an attenuation constant α, and the transmittance function T(θ,Φ) through the top interface. We demonstrate our theory on a pyramidal surface texture over a GaSb substrate at 4.5 μm wavelength by computing the expected LEE as a function of w.

  20. Lighting installations

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    Model computations that give the lay-out of a lighting installation have to be implemented in the real world. There, deviations from the ideal performance of just about every element of the installation will be felt. A list of possible sources of non-ideal behavior, based on practical experience, are: lamps, ballasts, reflectors, mounting position, sagging of lamps, and soiling. It is clear that with all possible deviations from the ideal the homogeneity of a real lighting installation can never be as good as the one computed. The only way to make sure it is nearly as good is by measurement of the actual light distribution. Then, an occasional adjustment or replacement may often yield a satisfactory result. This measurement should really be part of the installation contract.

  1. Light's Darkness

    ScienceCinema

    Padgett, Miles [University of Glasgow, Glasgow, Scotland

    2016-07-12

    Optical vortices and orbital angular momentum are currently topical subjects in the optics literature. Although seemingly esoteric, they are, in fact, the generic state of light and arise whenever three or more plane waves interfere. To be observed by eye the light must be monochromatic. Laser speckle is one such example, where the optical energy circulates around each black spot, giving a local orbital angular momentum. This talk with report three on-going studies. First, when considering a volume of interfering waves, the laser specs map out threads of complete darkness embedded in the light. Do these threads form loops? Links? Or even knots? Second, when looking through a rapidly spinning window, the image of the world on the other side is rotated: true or false? Finally, the entanglement of orbital angular momentum states means measuring how the angular position of one photons sets the angular momentum of another: is this an angular version of the EPR (Einstein, Podolsky, and Rosen) paradox?

  2. Slow and Fast Light in Coupled Microresonators

    NASA Technical Reports Server (NTRS)

    Chang, Hongrok; Smith, David D.; Fuller, Kirk A.; Dimmock, John O.; Gregory, Don A.; Frazier, Donald O.

    2005-01-01

    We predict the propagation of slow and fast light in two co-resonant coupled optical resonators. In coupled resonators, slow light can propagate without attenuation by a cancellation of absorption as a result of mode splitting and destructive interference, whereas transparent fast light propagation can be achieved by the assistance of gain and splitting of the intracavity resonances, which consequently change the dispersion from normal to anomalous. The effective steady-state response of coupled-resonators is derived using the temporal coupled-mode formalism, and the absorptive and dispersive responses are described. Specifically, the occurrence of slow light via coupled-resonator-induced transparency and gain-assisted fast light are discussed.

  3. Hearing light from an incandescent bulb

    NASA Astrophysics Data System (ADS)

    Zhu, Zheyuan; Du, Li; Zhang, Youtian; Wang, Sihui; Zhou, Huijun; Gao, Wenli

    2015-01-01

    In this paper, we present an interesting experiment to turn the vibratory light from an incandescent light bulb into audible sound. Inspired by research on the photoacoustic effect (PAE) using lasers, we construct a similar device in an undergraduate physics laboratory with everyday articles including light bulbs, glass beakers and soot. Using our device, a distinct sound is detected and analysed experimentally. Particular attention is paid to the attenuation effect of the acoustic signal, which can be explained by modifying the existing theory and using the adiabatic boundary condition according to the incident light source we use. This demonstration is a comprehensive experiment with the combination of sound, light and heat. The modification on the model can help undergraduate students gain an intuitive understanding of different boundary conditions.

  4. Science Requirements for Limits on Vent Tube Stray Light

    NASA Astrophysics Data System (ADS)

    Petro, L.

    2007-12-01

    The design of the WFC3 UVIS and IR detector vent tubes is intended to assure that the stray light on the science detectors from illumination by the bright Earth at the vent tube radiator openings is greatly attenuated. The limits on that stray light and the nominal attenuation required in order that the scientific quality of images is not significantly degraded are presented here. The stray light signal rate in the UVIS detector should be less than 5.0 electrons/sec/cm2, and less than 75 electrons/sec/cm2 for the IR detector. In order to meet these limits, the incident flux of the bright Earth on the vent tube opening must be attenuated at the detector by greater than 2×10^16 in the UVIS channel and 3-10^15 in the IR channel.

  5. Seismic Attenuation beneath Tateyama Volcano, Central Japan

    NASA Astrophysics Data System (ADS)

    Iwata, K.; Kawakata, H.; Doi, I.

    2014-12-01

    Subsurface structures beneath active volcanoes have frequently been investigated (e.g., Oikawa et al., 1994: Sudo et al., 1996), and seismic attenuation beneath some active volcanoes are reported to be strong. On the other hand, few local subsurface structures beneath volcanoes whose volcanic activities are low have been investigated in detail, though it is important to study them to understand the potential of volcanic activity of these volcanoes. Then, we analyzed the seismic attenuation beneath Tateyama volcano (Midagahara volcano) located in central Japan, whose volcanic activity is quite low. We used seismograms obtained by Hi-net deployed by NIED (National Research Institute for Earth Science and Disaster Prevention). Hi-net is one of the densest seismic station networks in the world, and the spatial interval of their seismographs is about 20 km, which is suitable for investigating local structure beneath an individual volcano. We estimated S-wave attenuation using seismograms at five stations near Tateyama volcano for nineteen small, local, shallow earthquakes (M 2.7-4.0) that occurred from January 2012 to December 2013. We divided these earthquakes into six groups according to their hypocenter locations. We used twofold spectral ratios around the first S-arrivals to investigate the S-wave attenuation when S-waves passed through the region beneath Tateyama volcano. We focused on station pairs located on opposite sides of Tateyama volcano to each other, and earthquake pairs whose epicenters were located almost along the line connecting Tateyama volcano and the two stations, so that the spectral ratios reflect a local structure beneath Tateyama volcano. Twofold spectral ratios of all seismograms for S waves having northwestern or southeastern sources show strong attenuation beneath Tateyama volcano. On the other hand, those of seismograms having northeastern or southwestern sources show much weaker attenuation, which suggested that the region of strong

  6. The Extravehicular Suit Impact Load Attenuation Study for Use in Astronaut Bone Fracture Prediction

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth E.; Gilkey, Kelly M.; Sulkowski, Christina M.; Samorezov, Sergey; Myers, Jerry G.

    2011-01-01

    The NASA Integrated Medical Model (IMM) assesses the risk, including likelihood and impact of occurrence, of all credible in-flight medical conditions. Fracture of the proximal femur is a traumatic injury that would likely result in loss of mission if it were to happen during spaceflight. The low gravity exposure causes decreases in bone mineral density which heightens the concern. Researchers at the NASA Glenn Research Center have quantified bone fracture probability during spaceflight with a probabilistic model. It was assumed that a pressurized extravehicular activity (EVA) suit would attenuate load during a fall, but no supporting data was available. The suit impact load attenuation study was performed to collect analogous data. METHODS: A pressurized EVA suit analog test bed was used to study how the offset, defined as the gap between the suit and the astronaut s body, impact load magnitude and suit operating pressure affects the attenuation of impact load. The attenuation data was incorporated into the probabilistic model of bone fracture as a function of these factors, replacing a load attenuation value based on commercial hip protectors. RESULTS: Load attenuation was more dependent on offset than on pressurization or load magnitude, especially at small offsets. Load attenuation factors for offsets between 0.1 - 1.5 cm were 0.69 +/- 0.15, 0.49 +/- 0.22 and 0.35 +/- 0.18 for mean impact forces of 4827, 6400 and 8467 N, respectively. Load attenuation factors for offsets of 2.8 - 5.3 cm were 0.93 +/- 0.2, 0.94 +/- 0.1 and 0.84 +/- 0.5, for the same mean impact forces. Reductions were observed in the 95th percentile confidence interval of the bone fracture probability predictions. CONCLUSIONS: The reduction in uncertainty and improved confidence in bone fracture predictions increased the fidelity and credibility of the fracture risk model and its benefit to mission design and operational decisions.

  7. Attenuation measurements of ultrasonic P-wave and S-wave in partially frozen unconsolidated sands

    NASA Astrophysics Data System (ADS)

    Matsushima, J.; Suzuki, M.; Kato, Y.; Rokugawa, S.; Kato, A.

    2012-12-01

    Seismic attenuation which controls both the amplitude decay of seismic waves and the accompanying frequency change is a signature of the wave-rock interaction. Seismic attenuation in rocks is a highly variable parameter, which depends on the confining pressure, porosity, degree of fluid saturation, and fluid type. Although seismic attenuation has been widely used to estimate physical conditions and rock properties in various fields, the loss mechanisms responsible for seismic attenuation often are unclear and controversial. To elucidate a plausible mechanism for seismic attenuation, the joint use of both P- and S-waves will provide more helpful information because these two types of waves respond differently to fluid and solid combinations. We have conducted ultrasonic P- and S-wave transmission measurements to examine the influence of ice-brine coexisting system grown in the pore space of unconsolidated sands on ultrasonic P- and S-waves. We observed the variations of a transmitted wave with a frequency content of 100-1000 kHz , changing its temperature from 20°C to -15°C. We use not only impulse-type signals but also sweep-type signals to prevent from the spectral leakage effect caused by the effect of windowing. We concern with attenuation at ultrasonic frequencies of 500-1000 kHz for P-waves and 100-400 kHz for S-waves. Our observation of the variation of the Poisson's ratio and the ratio of P- to S-wave attenuation with changing temperature indicates the possibilities of the joint use of both P- and S-waves to elucidate a plausible mechanism for seismic attenuation.

  8. Crustal Attenuation within the Turkish Plateau and Surrounding Regions

    NASA Astrophysics Data System (ADS)

    Zor, E.; Xie, J.; Turkelli, N.; Sandvol, E. A.; Mitchell, B. J.; Mellors, R.; Gasanov, A. H.; Yetirmishli, G.

    2005-12-01

    We have imaged lateral variations in the seismic attenuation in the crust from the inversion of inter-station Lg Q measurements in Turkey and the surrounding regions. We used data collected from three temporary arrays (ETSE, WTRN, ASN) and three permanent networks (KOERI,LLNL-JSO, GSN). We used approximately 2300 waveforms from ~200 events recorded at 75 stations in the region. Our tomographic model of Lg Qo is consistent with previous more qualitative Lg attenuation models that showed inefficient or blocked Lg across the Eurasian-Arabian plate boundary. We have also found, similar to the previous models, efficient Lg propagation throughout much of the Arabian plate. A substantial variation in Lg Qo values was also found for the Arabian peninsula (~250-800). The northern Arabian platform is generally had low to normal Lg Qo values (~250 to 350). In addition, we observe high Qo (~670-800) values for the southern Arabian Plate. Additionally, we have found a dramatic decrease in Lg Qo across the Bitlis suture; the plate boundary between the Arabian and Eurasian plates. Beneath the Turkish Plateau, our high to modestly high Lg attenuation values (Qo ~100 to 200) probably originate from both scattering and intrinsic attenuation due to the tectonic complexity and the wide spread young volcanics in the region. However, we think that the lowest Qo values for the East Anatolian plateau (~70 to 100) and the portion of western Turkey around the Menderes Massif (~60 to150) are most probably caused by intrinsic attenuation. Beneath the part of the Taurus Mountains in western Anatolia, normal Lg Qo values (~200-300) have been found. These relatively higher values may be related to the nature of the crust in the Tauride mountain belt that has created a stable continental crustal waveguide for east-west ray paths. For northeastern Turkey, the Caucasus and Azerbaijan, we also found some low to normal Lg Qo values (~170-180). We have also observed a fairly consistent negative

  9. Pore-Scale Modeling of Pore Structure Effects on P-Wave Scattering Attenuation in Dry Rocks

    PubMed Central

    Li, Tianyang; Qiu, Hao; Wang, Feifei

    2015-01-01

    Underground rocks usually have complex pore system with a variety of pore types and a wide range of pore size. The effects of pore structure on elastic wave attenuation cannot be neglected. We investigated the pore structure effects on P-wave scattering attenuation in dry rocks by pore-scale modeling based on the wave theory and the similarity principle. Our modeling results indicate that pore size, pore shape (such as aspect ratio), and pore density are important factors influencing P-wave scattering attenuation in porous rocks, and can explain the variation of scattering attenuation at the same porosity. From the perspective of scattering attenuation, porous rocks can safely suit to the long wavelength assumption when the ratio of wavelength to pore size is larger than 15. Under the long wavelength condition, the scattering attenuation coefficient increases as a power function as the pore density increases, and it increases exponentially with the increase in aspect ratio. For a certain porosity, rocks with smaller aspect ratio and/or larger pore size have stronger scattering attenuation. When the pore aspect ratio is larger than 0.5, the variation of scattering attenuation at the same porosity is dominantly caused by pore size and almost independent of the pore aspect ratio. These results lay a foundation for pore structure inversion from elastic wave responses in porous rocks. PMID:25961729

  10. Pore-scale modeling of pore structure effects on P-wave scattering attenuation in dry rocks.

    PubMed

    Wang, Zizhen; Wang, Ruihe; Li, Tianyang; Qiu, Hao; Wang, Feifei

    2015-01-01

    Underground rocks usually have complex pore system with a variety of pore types and a wide range of pore size. The effects of pore structure on elastic wave attenuation cannot be neglected. We investigated the pore structure effects on P-wave scattering attenuation in dry rocks by pore-scale modeling based on the wave theory and the similarity principle. Our modeling results indicate that pore size, pore shape (such as aspect ratio), and pore density are important factors influencing P-wave scattering attenuation in porous rocks, and can explain the variation of scattering attenuation at the same porosity. From the perspective of scattering attenuation, porous rocks can safely suit to the long wavelength assumption when the ratio of wavelength to pore size is larger than 15. Under the long wavelength condition, the scattering attenuation coefficient increases as a power function as the pore density increases, and it increases exponentially with the increase in aspect ratio. For a certain porosity, rocks with smaller aspect ratio and/or larger pore size have stronger scattering attenuation. When the pore aspect ratio is larger than 0.5, the variation of scattering attenuation at the same porosity is dominantly caused by pore size and almost independent of the pore aspect ratio. These results lay a foundation for pore structure inversion from elastic wave responses in porous rocks.

  11. Rift Valley Fever Virus MP-12 Vaccine Is Fully Attenuated by a Combination of Partial Attenuations in the S, M, and L Segments

    PubMed Central

    Hill, Terence E.; Smith, Jennifer K.; Zhang, Lihong; Juelich, Terry L.; Gong, Bin; Slack, Olga A. L.; Ly, Hoai J.; Lokugamage, Nandadeva; Freiberg, Alexander N.

    2015-01-01

    ABSTRACT Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and characterized by a high rate of abortion in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. RVF is caused by Rift Valley fever virus (RVFV; family Bunyaviridae, genus Phlebovirus), which has a tripartite negative-stranded RNA genome (consisting of the S, M, and L segments). Further spread of RVF into countries where the disease is not endemic may affect the economy and public health, and vaccination is an effective approach to prevent the spread of RVFV. A live-attenuated MP-12 vaccine is one of the best-characterized RVF vaccines for safety and efficacy and is currently conditionally licensed for use for veterinary purposes in the United States. Meanwhile, as of 2015, no other RVF vaccine has been conditionally or fully licensed for use in the United States. The MP-12 strain is derived from wild-type pathogenic strain ZH548, and its genome encodes 23 mutations in the three genome segments. However, the mechanism of MP-12 attenuation remains unknown. We characterized the attenuation of wild-type pathogenic strain ZH501 carrying a mutation(s) of the MP-12 S, M, or L segment in a mouse model. Our results indicated that MP-12 is attenuated by the mutations in the S, M, and L segments, while the mutations in the M and L segments confer stronger attenuation than those in the S segment. We identified a combination of 3 amino acid changes, Y259H (Gn), R1182G (Gc), and R1029K (L), that was sufficient to attenuate ZH501. However, strain MP-12 with reversion mutations at those 3 sites was still highly attenuated. Our results indicate that MP-12 attenuation is supported by a combination of multiple partial attenuation mutations and a single reversion mutation is less likely to cause a reversion to virulence of the MP-12 vaccine. IMPORTANCE Rift Valley fever (RVF) is a mosquito-transmitted viral disease that is endemic to Africa and that has the potential to

  12. Mutations within ICP4 acquired during in vitro attenuation do not alter virulence of recombinant Marek’s disease viruses in vivo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek's disease (MD) is a T-cell lymphoma of chickens caused by the oncogenic Marek's disease virus (MDV). MD is primarily controlled by live-attenuated vaccines generated by repeated in vitro serial passage. Previous efforts to characterize attenuated MDVs identified numerous mutations, particularl...

  13. School Lighting.

    ERIC Educational Resources Information Center

    Rennhackkamp, W. M. H.

    Research gathered by the Functional Efficiency Division of the National Building Research Institute, South Africa, is aimed at providing lighting conditions under which the school child can produce his maximum effort with the least strain and fatigue. These favorable conditions are outlined along with specific examples of their realization in…

  14. Assessment of the 1988 Saguenay earthquake: Implications on attenuation functions for seismic hazard analysis

    SciTech Connect

    Toro, G.R.; McGuire, R.K. )

    1991-09-01

    This study investigates the earthquake records from the 1988 Saguenay earthquake and examines the implications of these records with respect to ground-motion models used in seismic-hazard studies in eastern North America (ENA), specifically, to what extent the ground motions from this earthquake support or reject the various attenuation functions used in the EPRI and LLNL seismic-hazard calculations. Section 2 provides a brief description of the EPRI and LLNL attenuation functions for peak acceleration and for spectral velocities. Section 2 compares these attenuation functions the ground motions from the Saguenay earthquake and from other relevant earthquakes. Section 4 reviews available seismological studies about the Saguenay earthquake, in order to understand its seismological characteristics and why some observations may differ from predictions. Section 5 examines the assumptions and methodology used in the development of the attenuation functions selected by LLNL ground-motion expert 5. Finally, Section 6 draws conclusions about the validity of the various sets of attenuation functions, in light of the Saguenay data and of other evidence presented here. 50 refs., 37 figs., 7 tabs.

  15. Real-time control of the beam attenuation with XPAD hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Dawiec, A.; Garreau, Y.; Bisou, J.; Hustache, S.; Kanoute, B.; Picca, F.; Renaud, G.; Coati, A.

    2016-12-01

    In order to fully benefit from a beam produced by modern synchrotron light sources, characterised by a wide and continuous energy spectrum, high brightness and a very high intensity, advancement in detector technology has been made over the last decades. However, one of the main limitations of the state-of-the-art counting hybrid pixel detectors is the maximum count-rate that is very often few orders of magnitudes lower than of the incident, reflected or diffracted beam flux. Therefore, direct beam attenuation is mandatory in order to perform the measurements according to the detector's characteristics. In this work we present a major upgrade of a fast attenuation system developed at Synchrotron SOLEIL, which allows for a dynamical change of the beam attenuation as a function of the photon flux received by XPAD S140 photon counting detector. The system performs a cyclic real-time estimation of the flux received by every pixel during acquisition of an image and searches for clusters of at least two pixels that exceed user defined levels of counts/s. The beam attenuation is immediately and automatically changed in order to guarantee that the detector will always operate in its linear range even during a long continuous scan, by acting on the direct attenuators.

  16. Cocaine attenuates vasoconstriction to ethanol

    SciTech Connect

    Bove, A.A.; Morley, D.; Vosacek, R.; Zhang, X.Y.; Shah, R. )

    1991-03-11

    The purpose of this study was to determine the combined effects of cocaine and ethanol on vasomotor tone. Using a standard isolated vascular ring preparation, 24 rings from 7 New Zealand White Rabbits were studied. All rings were denuded as verified by methacholine challenge. The dose response to NE for each ring was used as a standard for vasoconstrictors Dose response curves to ETH and C were done in random order. Concentrations of both ETH and C employed were physiologically attainable in man and below thresholds for coma or death. The dose response curve to ETH was repeated after addition of 4 {times} 10{sup {minus}5} M C to the arterial bath. After adding 1,500 ug/ml of ETH, the dose response curve to C was repeated. Ethanol, alone caused significant vasoconstriction of arterial rings. After the addition of C to the bath, the dose response to ETH was significantly shifted to the right, peak contraction achieved was 36.6 {plus minus} 3.2% of maximal NE contraction. Cocaine alone did not result in any change in resting tension of the rings. When ETH was added to the bath, C caused vasoconstriction, the peak value equivalent to 12.5 {plus minus} 2.2% of maximal contraction to NE.

  17. A simple model for deep tissue attenuation correction and large organ analysis of Cerenkov luminescence imaging

    NASA Astrophysics Data System (ADS)

    Habte, Frezghi; Natarajan, Arutselvan; Paik, David S.; Gambhir, Sanjiv S.

    2014-03-01

    Cerenkov luminescence imaging (CLI) is an emerging cost effective modality that uses conventional small animal optical imaging systems and clinically available radionuclide probes for light emission. CLI has shown good correlation with PET for organs of high uptake such as kidney, spleen, thymus and subcutaneous tumors in mouse models. However, CLI has limitations for deep tissue quantitative imaging since the blue-weighted spectral characteristics of Cerenkov radiation attenuates highly by mammalian tissue. Large organs such as the liver have also shown higher signal due to the contribution of emission of light from a greater thickness of tissue. In this study, we developed a simple model that estimates the effective tissue attenuation coefficient in order to correct the CLI signal intensity with a priori estimated depth and thickness of specific organs. We used several thin slices of ham to build a phantom with realistic attenuation. We placed radionuclide sources inside the phantom at different tissue depths and imaged it using an IVIS Spectrum (Perkin-Elmer, Waltham, MA, USA) and Inveon microPET (Preclinical Solutions Siemens, Knoxville, TN). We also performed CLI and PET of mouse models and applied the proposed attenuation model to correct CLI measurements. Using calibration factors obtained from phantom study that converts the corrected CLI measurements to %ID/g, we obtained an average difference of less that 10% for spleen and less than 35% for liver compared to conventional PET measurements. Hence, the proposed model has a capability of correcting the CLI signal to provide comparable measurements with PET data.

  18. Channel modeling of light signals propagating through a battlefield environment: analysis of channel spatial, angular, and temporal dispersion.

    PubMed

    Wu, Binbin; Marchant, Brian; Kavehrad, Mohsen

    2007-09-01

    Free-space optical communication (FSOC) is used to transmit a modulated beam of light through the atmosphere for broadband applications. Fundamental limitations of FSOC arise from the environment through which light propagates. We address transmitted light signal dispersion (spatial, angular, and temporal dispersion) in FSOC that operates in the battlefield environment. Light signals (photons) transmitted through the battlefield environment will interact with particles of man-made smoke such as fog oil, along the propagation path. Photon-particle interaction causes dispersion of light signals, which has significant effects on signal attenuation and pulse spread. We show that physical properties of battlefield particles play important roles in determining dispersion of received light signals. The correlation between spatial and angular dispersion is investigated as well, which has significant effects on receiver design issues. Moreover, our research indicates that temporal dispersion (delay spread) and the received power strongly depend on the receiver aperture size, field of view (FOV), and the position of the receiver relative to the optical axis of the transmitter. The results describe only specific scenarios for given types of battlefield particles. Generalization of the results requires additional work. Based on properties of the correlation, a sensitive receiver with a small FOV is needed that can find the line-of-sight photons and work with them.

  19. Attenuation coefficient of single-mode periodic waveguides.

    PubMed

    Baron, A; Mazoyer, S; Smigaj, W; Lalanne, P

    2011-10-07

    It is widely accepted that, on ensemble average, the transmission T of guided modes decays exponentially with the waveguide length L due to small imperfections, leading to the important figure of merit defined as the attenuation-rate coefficient α=-⟨ln(T)⟩/L. In this Letter, we evidence that the exponential-damping law is not valid in general for periodic monomode waveguides, especially as the group velocity decreases. This result, that contradicts common beliefs and experimental practices aiming at measuring α, is supported by a theoretical study of light transport in the limit of very small imperfections, and by numerical results obtained for two waveguide geometries that offer contrasted damping behaviors.

  20. Attenuation Coefficient of Single-Mode Periodic Waveguides

    NASA Astrophysics Data System (ADS)

    Baron, A.; Mazoyer, S.; Smigaj, W.; Lalanne, P.

    2011-10-01

    It is widely accepted that, on ensemble average, the transmission T of guided modes decays exponentially with the waveguide length L due to small imperfections, leading to the important figure of merit defined as the attenuation-rate coefficient α=-⟨ln⁡(T)⟩/L. In this Letter, we evidence that the exponential-damping law is not valid in general for periodic monomode waveguides, especially as the group velocity decreases. This result, that contradicts common beliefs and experimental practices aiming at measuring α, is supported by a theoretical study of light transport in the limit of very small imperfections, and by numerical results obtained for two waveguide geometries that offer contrasted damping behaviors.

  1. MODIS Solar Diffuser Attenuation Screen Modeling Results

    NASA Technical Reports Server (NTRS)

    Waluschka, Eugene; Xuong, Xiaoxiong; Guenther, Bruce; Barnes, William

    2004-01-01

    On-orbit calibration of the reflected solar bands on the EOS Moderate Resolution Imaging Spectroradiometer (MODIS) is accomplished by have the instrument view a high reflectance diffuse surface illuminated by the sun. For some of the spectral bands this proves to be much too bright a signal that results in the saturation of detectors designed for measuring low reflectance (ocean) surfaces signals. A mechanical attenuation device in the form of a pin hole screen is used to reduce the signals to calibrate these bands. The sensor response to solar illumination of the SD with and without the attenuation screen in place will be presented. The MODIS detector response to the solar diffuser is smooth when the attenuation screen is absent, but has structures up to a few percent when the attenuation screen is present. This structure corresponds to non-uniform illumination from the solar diffuser. Each pin hole produces a pin-hole image of the sun on the solar diffuser, and there are very many pin hole images of the sun on the solar diffuser for each MODIS detector. Even though there are very many pin-hole images of the sun on the solar diffuser, it is no longer perfectly uniformly illuminated. This non-uniformly illuminated solar diffuser produces intensity variation on the focal planes. The results of a very detailed simulation will be discussed which show how the illumination of the focal plane changes as a result of the attenuation, and the impacts on the calibration will be discussed.

  2. Enabling photon counting detectors with dynamic attenuators

    NASA Astrophysics Data System (ADS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-03-01

    Photon-counting x-ray detectors (PCXDs) are being investigated as a replacement for conventional x-ray detectors because they promise several advantages, including better dose efficiency, higher resolution and spectral imaging. However, many of these advantages disappear when the x-ray flux incident on the detector is too high. We recently proposed a dynamic, piecewise-linear attenuator (or beam shaping filter) that can control the flux incident on the detector. This can restrict the operating range of the PCXD to keep the incident count rate below a given limit. We simulated a system with the piecewise-linear attenuator and a PCXD using raw data generated from forward projected DICOM files. We investigated the classic paralyzable and nonparalyzable PCXD as well as a weighted average of the two, with the weights chosen to mimic an existing PCXD (Taguchi et al, Med Phys 2011). The dynamic attenuator has small synergistic benefits with the nonparalyzable detector and large synergistic benefits with the paralyzable detector. Real PCXDs operate somewhere between these models, and the weighted average model still shows large benefits from the dynamic attenuator. We conclude that dynamic attenuators can reduce the count rate performance necessary for adopting PCXDs.

  3. Attenuation tomography in West Bohemia/Vogtland

    NASA Astrophysics Data System (ADS)

    Mousavi, Sima; Haberland, Christian; Bauer, Klaus; Hejrani, Babak; Korn, Michael

    2017-01-01

    We present a three-dimensional (3-D) P-wave attenuation (Qp) model for the geodynamically active swarm earthquake area of West Bohemia/Vogtland in the Czech/German border region. Path-averaged attenuation t* is calculated from amplitude spectra of time windows around the P-wave arrivals of local earthquakes. Average t/t* value or Qp for stations close to Nový Kostel are very low (< 150) compared to that of stations located further away from the focal zone (increases up to 500 within 80 km distance). The SIMUL2000 tomography scheme is used to invert the t* for P-wave attenuation perturbation. Analysis of resolution shows that our model is well-resolved in the vicinity of earthquake swarm hypocenters. The prominent features of the model are located around Nový Kostel focal zone and its northern vicinity. Beneath Nový Kostel a vertically stretched (down to depth of 11 km) and a highly attenuating body is observed. We believe that this is due to fracturing and high density of cracks inside the weak earthquake swarm zone in conjunction with presence of free gas/fluid. Further north of Nový Kostel two highly attenuating bodies are imaged which could represent fluid channels toward the surface. The eastern anomaly shows a good correlation with the fluid accumulation area which was suggested in 9HR seismic profile.

  4. Filtered back-projection reconstruction for attenuation proton CT along most likely paths.

    PubMed

    Quiñones, C T; Létang, J M; Rit, S

    2016-05-07

    This work investigates the attenuation of a proton beam to reconstruct the map of the linear attenuation coefficient of a material which is mainly caused by the inelastic interactions of protons with matter. Attenuation proton computed tomography (pCT) suffers from a poor spatial resolution due to multiple Coulomb scattering (MCS) of protons in matter, similarly to the conventional energy-loss pCT. We therefore adapted a recent filtered back-projection algorithm along the most likely path (MLP) of protons for energy-loss pCT (Rit et al 2013) to attenuation pCT assuming a pCT scanner that can track the position and the direction of protons before and after the scanned object. Monte Carlo simulations of pCT acquisitions of density and spatial resolution phantoms were performed to characterize the new algorithm using Geant4 (via Gate). Attenuation pCT assumes an energy-independent inelastic cross-section, and the impact of the energy dependence of the inelastic cross-section below 100 MeV showed a capping artifact when the residual energy was below 100 MeV behind the object. The statistical limitation has been determined analytically and it was found that the noise in attenuation pCT images is 411 times and 278 times higher than the noise in energy-loss pCT images for the same imaging dose at 200 MeV and 300 MeV, respectively. Comparison of the spatial resolution of attenuation pCT images with a conventional straight-line path binning showed that incorporating the MLP estimates during reconstruction improves the spatial resolution of attenuation pCT. Moreover, regardless of the significant noise in attenuation pCT images, the spatial resolution of attenuation pCT was better than that of conventional energy-loss pCT in some studied situations thanks to the interplay of MCS and attenuation known as the West-Sherwood effect.

  5. Filtered back-projection reconstruction for attenuation proton CT along most likely paths

    NASA Astrophysics Data System (ADS)

    Quiñones, C. T.; Létang, J. M.; Rit, S.

    2016-05-01

    This work investigates the attenuation of a proton beam to reconstruct the map of the linear attenuation coefficient of a material which is mainly caused by the inelastic interactions of protons with matter. Attenuation proton computed tomography (pCT) suffers from a poor spatial resolution due to multiple Coulomb scattering (MCS) of protons in matter, similarly to the conventional energy-loss pCT. We therefore adapted a recent filtered back-projection algorithm along the most likely path (MLP) of protons for energy-loss pCT (Rit et al 2013) to attenuation pCT assuming a pCT scanner that can track the position and the direction of protons before and after the scanned object. Monte Carlo simulations of pCT acquisitions of density and spatial resolution phantoms were performed to characterize the new algorithm using Geant4 (via Gate). Attenuation pCT assumes an energy-independent inelastic cross-section, and the impact of the energy dependence of the inelastic cross-section below 100 MeV showed a capping artifact when the residual energy was below 100 MeV behind the object. The statistical limitation has been determined analytically and it was found that the noise in attenuation pCT images is 411 times and 278 times higher than the noise in energy-loss pCT images for the same imaging dose at 200 MeV and 300 MeV, respectively. Comparison of the spatial resolution of attenuation pCT images with a conventional straight-line path binning showed that incorporating the MLP estimates during reconstruction improves the spatial resolution of attenuation pCT. Moreover, regardless of the significant noise in attenuation pCT images, the spatial resolution of attenuation pCT was better than that of conventional energy-loss pCT in some studied situations thanks to the interplay of MCS and attenuation known as the West-Sherwood effect.

  6. Effects of disturbances caused by coastal constructions on spatial structure, growth dynamics and photosynthesis of the seagrass Posidonia oceanica.

    PubMed

    Ruiz, J M; Romero, J

    2003-12-01

    The light-limitation hypothesis was tested to assess whether water turbidity had caused the decline of a Mediterranean Posidonia oceanica (L.) Delile meadow in an area affected by a harbor. The annual growth, photosynthesis and rhizome starch concentrations of seagrass were measured and related to changes in light availability and dissolved nutrient concentration along a gradient of meadow degradation from areas close to the harbor outwards. Environmental and plant variables were measured in three stations placed along this gradient and compared with a reference station at an undisturbed meadow. The light attenuation coefficient (k) increased toward the inner harbor area, mainly due to sediment resuspension. The shoot density and leaf productivity of P. oceanica shoots were much lower in disturbed stations of the inner harbor area than in the outer, less disturbed station and the reference meadow. However, daily leaf carbon gains, calculated from the photosynthetic rates at saturating irradiance (P(max)) and the daily period in which seagrass receives light higher than its saturating irradiance (H(sat)), suggested positive C-balance in all stations. This was partly explained by photo-acclimatization of seagrass to the reduced light availability at the disturbed harbor stations (inner and intermediate), as indicated by the lengthening of H(sat) and the decrease in saturating irradiance (I(sat)) and respiratory demands. Despite photo-acclimatization, disturbed harbor stations showed less positive C-balance, seen not only in their lower leaf growth and biomass but also in a decrease in rhizome carbohydrate reserves (starch). Our results suggest that light reduction account for the reduced seagrass productivity and abundance. However, meadow decline (in terms of shoot mortality) in the harbor area is well above that predicted from similar light environments of nearby meadows or simulated in shading experiments. Thus, there are other factors than light limitation

  7. Effects of fluid and light dynamics on H2 production in a mechanically stirred photobioreactor.

    PubMed

    Zhang, T

    2013-10-01

    Hydrogen productions through biophotolysis by microalgae in photobioreactors (PBRs) were studied using a computational model integrated with fluid dynamics, particle tracking technique, light attenuation dynamics, biochemical kinetics, and mass transport. The trajectories of microalgae entrained in the flow fields within these PBRs were traced by the particle tracking technique and were used to determine the dynamics of light attenuation subjected by the cells, which were analyzed and compared with those obtained from the unstirred PBR under different incident light illuminations. The results show an improvement on the light penetration depth in the mechanically stirred cultures. The dynamics of light attenuation was incorporated into the kinetics equations for the analysis of the inhomogeneous biochemical process for hydrogen production by microalgae. Hydrogen production in the unstirred and the impeller-stirred PBRs were determined under different light illumination conditions and the results show an improvement on hydrogen production in the impeller-stirred PBRs.

  8. General Molecular Strategy for Development of Arenavirus Live-Attenuated Vaccines

    PubMed Central

    Iwasaki, Masaharu; Ngo, Nhi; Cubitt, Beatrice; Teijaro, John R.

    2015-01-01

    ABSTRACT Hemorrhagic fever arenaviruses (HFA) pose important public health problems in regions where they are endemic. Thus, Lassa virus (LASV) infects several hundred thousand individuals yearly in West Africa, causing a large number of Lassa fever cases associated with high morbidity and mortality. Concerns about human-pathogenic arenaviruses are exacerbated because of the lack of FDA-licensed arenavirus vaccines and because current antiarenaviral therapy is limited to an off-label use of ribavirin that is only partially effective. The Mopeia virus (MOPV)/LASV reassortant (ML29) is a LASV candidate live-attenuated vaccine (LAV) that has shown promising results in animal models. Nevertheless, the mechanism of ML29 attenuation remains unknown, which raises concerns about the phenotypic stability of ML29 in response to additional mutations. Development of LAVs based on well-defined molecular mechanisms of attenuation will represent a major step in combatting HFA. We used the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) to develop a general molecular strategy for arenavirus attenuation. Our approach involved replacement of the noncoding intergenic region (IGR) of the L genome segment with the IGR of the S genome segment to generate a recombinant LCMV, rLCMV(IGR/S-S), that was highly attenuated in vivo but induced protection against a lethal challenge with wild-type LCMV. Attenuation of rLCMV(IGR/S-S) was associated with a stable reorganization of the control of viral gene expression. This strategy can facilitate the rapid development of LAVs with the antigenic composition of the parental HFA and a mechanism of attenuation that minimizes concerns about increased virulence that could be caused by genetic changes in the LAV. IMPORTANCE Hemorrhagic fever arenaviruses (HFA) cause high morbidity and mortality, and pose important public health problems in the regions where they are endemic. Implementation of live-attenuated vaccines (LAV) will represent a

  9. [LIGHT POLLUTION AS THE HYGIENIC PROBLEM].

    PubMed

    Kaptsov, V A; Gerasev, V F; Deynego, V N

    2015-01-01

    Mass introduction of lighting devices according to the concept of "maximum coverage area" and multistoried buildings of cities gave rise to light pollution, which became a problem for astronomers, ecologists and hygienists. Analysis of modern lighting devices and installations has shown that about 30-45% of the luminous flux becomes the light pollution. Night lighting of cities causes both direct and indirect damage to the environment, leads to unnecessary energy wastes. So in the USA due to excessive light there is wasted about 2 million barrels of oil per day. Light pollution affects the human hormonal system, causing various health disorders, such as insomnia and depression as a consequence. The light pollution through the ganglion cells of the retina affects the synthesis of melatonin by the pineal gland (epiphysis) and contributes to its calcification, which greatly affects the human psyche. At present, many countries have been paying much state attention to this problem via delivery of national documents and change of the concept of the designing of lighting devices and installations. The essence of this concept--to shine with a preset quality of light only in the right place at the specified time interval. This reduces the light pollution, saves energy and increases the environmental safety of lighting. There is presented an example of a technical solution to reduce the light pollution in the application of the light panel in the form of the gradient of the light guide generator project development.

  10. Study on laser and infrared attenuation performance of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, Xiang-cui; Liu, Qing-hai; Dai, Meng-yan; Cheng, Xiang; Fang, Guo-feng; Zhang, Tong; Liu, Haifeng

    2014-11-01

    In recent years, the weapon systems of laser and infrared (IR) imaging guidance have been widely used in modern warfare because of their high precision and strong anti-interference. However, military smoke, a rapid and effective passive jamming method, can effectively counteract the attack of precision-guided weapons by their scattering and absorbing effects. The traditional smoke has good visible light (0.4-0.76μm) obscurant performance, but hardly any effects to other electromagnetic wave bands while the weapon systems of laser and IR imaging guidance usually work in broad band, including the near-infrared (1-3μm), middle-infrared (3-5μm), far-infrared (8-14μm), and so on. Accordingly, exploiting new effective obscurant materials has attracted tremendous interest worldwide nowadays. As is known, the nano-structured materials have lots of unique properties comparing with the traditional materials suggesting that they might be the perfect alternatives to solve the problems above. Carbon nanotubes (CNTs) are well-ordered, all-carbon hollow graphitic nano-structured materials with a high aspect ratio, lengths from several hundred nanometers to several millimeters. CNTs possess many unique intrinsic physical-chemical properties and are investigated in many areas reported by the previous studies. However, no application research about CNTs in smoke technology field is reported yet. In this paper, the attenuation performances of CNTs smoke to laser and IR were assessed in 20m3 smoke chamber. The testing wavebands employed in experiments are 1.06μm and 10.6μm laser, 3-5μm and 8-14μm IR radiation. The main parameters were obtained included the attenuation rate, transmission rate, mass extinction coefficient, etc. The experimental results suggest that CNTs smoke exhibits excellent attenuation ability to the broadband IR radiation. Their mass extinction coefficients are all above 1m2·g-1. Nevertheless, the mass extinction coefficients vary with the sampling time

  11. Live attenuated vaccines for invasive Salmonella infections

    PubMed Central

    Tennant, Sharon M.; Levine, Myron M.

    2015-01-01

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed S. Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: S. Typhi, S. Paratyphi A, S. Paratyphi B (currently uncommon but may become dominant again), S. Typhimurium, S. Enteritidis and S. Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines. PMID:25902362

  12. Live attenuated vaccines for invasive Salmonella infections.

    PubMed

    Tennant, Sharon M; Levine, Myron M

    2015-06-19

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed Salmonella Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B (currently uncommon but may become dominant again), Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines.

  13. Slow light in ruby: delaying energy beyond the input pulse

    NASA Astrophysics Data System (ADS)

    Wisniewski-Barker, Emma; Gibson, Graham; Franke-Arnold, Sonja; Shi, Zhimin; Narum, Paul; Boyd, Robert W.; Padgett, Miles J.

    2015-03-01

    The mechanism by which light is slowed through ruby has been the subject of great debate. To distinguish between the two main proposed mechanisms, we investigate the problem in the time domain by modulating a laser beam with a chopper to create a clean square wave. By exploring the trailing edge of the pulsed laser beam propagating through ruby, we can determine whether energy is delayed beyond the input pulse. The effects of a time-varying absorber alone cannot delay energy into the trailing edge of the pulse, as a time-varying absorber can only attenuate a coherent pulse. Therefore, our observation of an increase in intensity at the trailing edge of the pulse provides evidence for a complicated model of slow light in ruby that requires more than just pulse reshaping. In addition, investigating the Fourier components of the modulated square wave shows that harmonic components with different frequencies are delayed by different amounts, regardless of the intensity of the component itself. Understanding the difference in delays of the individual Fourier components of the modulated beam reveals the cause of the distortion the pulse undergoes as it propagates through the ruby.

  14. No-Light Light Bulbs

    ERIC Educational Resources Information Center

    Modern Schools, 1976

    1976-01-01

    A thumbnail sketch of some of the light bulbs manufactured for a purpose other than seeing. These "dark" lamps perform varied tasks including keeping food fresh, detecting and preventing disease, spurring plant growth, heating, and copying printed material. (Author/MLF)

  15. Light Pollution and Wildlife

    NASA Astrophysics Data System (ADS)

    Duffek, J.

    2008-12-01

    for Educational Program IYA Dark Skies Education Session Fall American Geophysical Union San Francisco, December 15-19, 2008 Light Pollution and Wildlife This is a very exciting time to be a part of the mission to keep the nighttime skies natural. The International Year of Astronomy (IYA) 2009 is developing programs for all areas of Dark Skies Awareness. For many years the issue of light pollution focused on the impact to the astronomy industry. While this is an important area, research has shown that light pollution negatively impacts wildlife, their habitat, human health, and is a significant waste of energy. Since the message and impact of the effects of light pollution are much broader now, the message conveyed to the public must also be broader. Education programs directed at youth are a new frontier to reach out to a new audience about the adverse effects of too much artificial light at night. The International Dark-Sky Association (IDA) has developed educational presentations using the National Science Teachers Association Education Standards. These programs focus on youth between the ages of 5 to 17exploring new territory in the education of light pollution. The IDA education programs are broken down into three age groups; ages 5-9, 8-13, 12 and older. The presentations come complete with PowerPoint slides, discussion notes for each slide, and workbooks including age appropriate games to keep young audiences involved. A new presentation reflects the growing area of interest regarding the effects of too much artificial light at night on wildlife. This presentation outlines the known problems for ecosystems caused by artificial light at night. Insects are attracted to artificial lights and may stay near that light all night. This attraction interferes with their ability to migrate, mate, and look for food. Such behavior leads to smaller insect populations. Fewer insects in turn affect birds and bats, because they rely on insects as a food source. The IDA

  16. Is there seismic attenuation in the mantle?

    NASA Astrophysics Data System (ADS)

    Ricard, Y.; Durand, S.; Montagner, J.-P.; Chambat, F.

    2014-02-01

    The small scale heterogeneity of the mantle is mostly due to the mixing of petrological heterogeneities by a smooth but chaotic convection and should consist in a laminated structure (marble cake) with a power spectrum S(k) varying as 1/k, where k is the wavenumber of the anomalies. This distribution of heterogeneities during convective stirring with negligible diffusion, called Batchelor regime is documented by fluid dynamic experiments and corresponds to what can be inferred from geochemistry and seismic tomography. This laminated structure imposes density, seismic velocity and potentially, anisotropic heterogeneities with similar 1/k spectra. A seismic wave of wavenumber k0 crossing such a medium is partly reflected by the heterogeneities and we show that the scattered energy is proportional to k0S(2k0). The reduction of energy for the propagating wave appears therefore equivalent to a quality factor 1/Q∝k0S(2k0). With the specific 1/k spectrum of the mantle, the resulting apparent attenuation should therefore be frequency independent. We show that the total contribution of 6-9% RMS density, velocity and anisotropy would explain the observed S and P attenuation of the mantle. Although these values are large, they are not unreasonable and we discuss how they depend on the range of frequencies over which the attenuation is explained. If such a level of heterogeneity were present, most of the attenuation of the Earth would be due to small scale scattering by laminations, not by intrinsic dissipation. Intrinsic dissipation must certainly exist but might correspond to a larger, yet unobserved Q. This provocative result would explain the very weak frequency dependence of the attenuation, and the fact that bulk attenuation seems negligible, two observations that have been difficult to explain for 50 years.

  17. Crustal structure of the Alps as seen by attenuation tomography

    NASA Astrophysics Data System (ADS)

    Mayor, Jessie; Calvet, Marie; Margerin, Ludovic; Vanderhaeghe, Olivier; Traversa, Paola

    2016-04-01

    between low-attenuation regions to the North and high-attenuation region to the South correlates geographically with the location of the Periadriatic Lineament (PL), a major late-alpine crustal- to lithospheric-scale structure. Furthermore, the attenuation structure seems to prolong the PL to the West along a line marked by large historical earthquakes. The Apennines orogenic belts exhibit a distinct frequency behavior, with high attenuation at low-frequency and low-attenuation at high-frequency. Low-frequency absorption may likely be explained by the relatively thick cover of Cenozoic sedimentary materials, as well as by shallow geothermal activity. We hypothesize that the frequency dependence of the attenuation structure, in particular in the Apennines, is caused by a change of the wavefield composition which accentuates the sensitivity of the coda to the deeper parts of the medium as the frequency increases.

  18. Shining Light on the Differences in Molecular Structural Chemical Makeup and the Cause of Distinct Degradation Behavior Between Malting- and Feed- Type Barley Using Synchrotorn FTIR Microspectroscopy: A Novel Approach

    SciTech Connect

    Yu,P.; Doiron, K.; Liu, D.

    2008-01-01

    The objective of this study was to use advanced synchrotron-sourced FTIR microspectroscopy (SFTIRM) as a novel approach to identify the differences in protein and carbohydrate molecular structure (chemical makeup) between these two varieties of barley and illustrate the exact causes for their significantly different degradation kinetics. Items assessed included (1) molecular structural differences in protein amide I to amide II intensities and their ratio within cellular dimensions, (2) molecular structural differences in protein secondary structure profile and their ratios, and (3) molecular structural differences in carbohydrate component peak profile. Our hypothesis was that molecular structure (chemical makeup) affects barley quality, fermentation, and degradation behavior in both humans and animals. Using SFTIRM, the protein and carbohydrate molecular structural chemical makeup of barley was revealed and identified. The protein molecular structural chemical makeup differed significantly between the two varieties of barleys. No difference in carbohydrate molecular structural chemical makeup was detected. Harrington was lower than Valier in protein amide I, amide II, and protein amide I to amide II ratio, while Harrington was relatively higher in model-fitted protein a-helix and {beta}-sheet, but lower in the others ({beta}-turn and random coil). These results indicated that it is the molecular structure of protein (chemical makeup) that may play a major role in the different degradation kinetics between the two varieties of barleys (not the molecular structure of carbohydrate). It is believed that use of the advanced synchrotron technology will make a significant step and an important contribution to research in examining the molecular structure (chemical makeup) of plant, feed, and seeds.

  19. Shining light on the differences in molecular structural chemical makeup and the cause of distinct degradation behavior between malting- and feed-type barley using synchrotron FTIR microspectroscopy: a novel approach.

    PubMed

    Yu, Peiqiang; Doiron, Kevin; Liu, Dasen

    2008-05-14

    The objective of this study was to use advanced synchrotron-sourced FTIR microspectroscopy (SFTIRM) as a novel approach to identify the differences in protein and carbohydrate molecular structure (chemical makeup) between these two varieties of barley and illustrate the exact causes for their significantly different degradation kinetics. Items assessed included (1) molecular structural differences in protein amide I to amide II intensities and their ratio within cellular dimensions, (2) molecular structural differences in protein secondary structure profile and their ratios, and (3) molecular structural differences in carbohydrate component peak profile. Our hypothesis was that molecular structure (chemical makeup) affects barley quality, fermentation, and degradation behavior in both humans and animals. Using SFTIRM, the protein and carbohydrate molecular structural chemical makeup of barley was revealed and identified. The protein molecular structural chemical makeup differed significantly between the two varieties of barleys. No difference in carbohydrate molecular structural chemical makeup was detected. Harrington was lower than Valier in protein amide I, amide II, and protein amide I to amide II ratio, while Harrington was relatively higher in model-fitted protein alpha-helix and beta-sheet, but lower in the others (beta-turn and random coil). These results indicated that it is the molecular structure of protein (chemical makeup) that may play a major role in the different degradation kinetics between the two varieties of barleys (not the molecular structure of carbohydrate). It is believed that use of the advanced synchrotron technology will make a significant step and an important contribution to research in examining the molecular structure (chemical makeup) of plant, feed, and seeds.

  20. Modeling Attenuation and Phase of Radio Waves in Air at Frequencies Below 1000 GHz

    DTIC Science & Technology

    1981-12-01

    center frequency for each line; (2) an empirical 1 water vapor continuum spectrum: and (3) a liquid water attenuation term for haze and cloud conditions...INTRODUCTION penetrate a somewhat opaque atmosphere (haze, The physical properties of the neutral atmosphere fog, clouds , dust, smoke, light rain) under...responsible-a kind of ’invisible’ hydrogen-bonded dimers and/or clusters of selec- cloud (Nilsson, 19791. tive size distributions (10-30 H 20 molecules

  1. Light Sources and Lighting Circuits

    NASA Astrophysics Data System (ADS)

    Honda, Hisashi; Suwa, Takumi; Yasuda, Takeo; Ohtani, Yoshihiko; Maehara, Akiyoshi; Okada, Atsunori; Komatsu, Naoki; Mannami, Tomoaki

    According to the Machinery Statistics of the Ministry of Economy, Trade and Industry, the production of incandescent lamps in Japan in 2007 was 990 million units (90.0% of the previous year's total), in which the production of incandescent lamps for general lighting was 110 million units (90.0% of the previous year's total) and of tungsten-halogen lamps was 44 million units (96.6% of the previous year's total). The production of fluorescent lamps was 927 million units (93.9% of the previous year's total), in which general fluorescent lamps, excluding those for LCD back lighting, was 320 million units (87.2% of the previous year's total). Also, the production of HID lamps was 10 million units (101.5% of the previous year's total). On the other hand, when the numbers of sales are compared with the sales of the previous year, incandescent lamps for general use was 99.8%, tungsten-halogen lamps was 96.9%, fluorescent lamps was 95.9%, and HID lamps was 98.9%. Self-ballasted fluorescent lamps alone showed an increase in sales as strong as 29 million units, or 121.7% of the previous year's sales. It is considered that the switchover of incandescent lamps to HID lamps was promoted for energy conservation and carbon dioxide reduction with the problem of global warming in the background. In regard to exhibitions, Lighting Fair 2007 was held in Tokyo in March, and LIGHTFAIR INTERNATIONAL 2007 was held in New York in May. Regarding academic conferences, LS:11 (the 11th International Symposium on the Science & Technology of Light Sources) was held in Shanghai in May, and the First International Conference on White LEDs and Solid State Lighting was held in Tokyo in November. Both conferences suggested that there are strong needs and concerns now about energy conservation, saving natural resources, and restrictions of hazardous materials. In regard to incandescent lamps, the development of products aiming at higher efficacy, electric power savings, and longer life was advanced by

  2. Real-Ear Attenuation Testing System (RATS)

    DTIC Science & Technology

    1991-01-01

    transmission of noise from outside the chamber through vibrations of the walls. The four walls of the new chamber are made up of two double layers of drywall ... drywall separated by 2’ x 10" joists and a layer of fiberglass blanket insulation. The edges of the new chamber and door frame are sealed with acoustic...amount of attenuation the Wil sonics attenuators must provide to obtain the minimum SPL is shown in row 9. Table 10 compares the maximum SPL required

  3. PLC signal attenuation in branched networks

    SciTech Connect

    Durbak, D.W.; Stewart, J.R. )

    1990-04-01

    The application of power line carrier (PLC) to utility transmission systems can provide a reliable means of communication over short and long distances. However, PLC performance is dependent upon an adequate signal-to-noise ratio at receivers. The calculation of path attenuation of signals on the transmission line can be complicated, especially in branched networks. The calculation method described here is based on the construction of an impedance matrix using multi-phase, long line pi-equivalents for transmission lines. The method can predict PLC attenuation for a variety of network topologies and is demonstrated for two cases.

  4. Glareless light-emitting diode lighting tube

    NASA Astrophysics Data System (ADS)

    Chang, Rong-Seng; Li, Tung-Yen; Jwo, Ko-Wen; Wang, Sha-Wei; Tsai, Jang-Zern

    2012-03-01

    We develop a novel light bar waveguide design to produce a glareless light-emitting diode (LED) lighting tube. We design optimal parameters, such as the gap y between the tube and the reflective surface, the relative distance x between the lens and the LED, and so on. Using these parameters, we fabricate an illumination system consisting of LED light bulb installed at both ends of lighting tube. The lighting tube is shaped the same as a traditional fluorescent lighting tube in order to replace traditional lighting tubes without the modification of the lighting stand. The LED lighting tube is glareless to the observer from the side view.

  5. Activation and genetic modification of human monocyte-derived dendritic cells using attenuated Salmonella typhimurium.

    PubMed

    Michael, Agnieszka; John, Justin; Meyer, Brendan; Pandha, Hardev

    2010-03-05

    Live attenuated bacterial vectors, such as Salmonella typhimurium, have shown promise as delivery vehicles for DNA. We have examined two new strains of S. typhimurium and their impact on dendritic cell maturation (CD12-sifA/aroC mutant and WT05-ssaV/aroC, both in TML background). Strain WT05 matured dendritic cells in a more efficient way; caused higher release of cytokines TNF-alpha, IL-12, IL-1beta; and was efficient for gene transfer. These findings suggest that the genetic background of the attenuation can influence the pattern of inflammatory immune response to Salmonella infection.

  6. Carbon nanotubes attenuate cancer and improve healing

    NASA Astrophysics Data System (ADS)

    Wailes, Elizabeth Marguerite

    Breast cancer is the most common cancer in American women and the second largest cause of their cancer mortality. Resection of the primary tumor can greatly improve the prognosis, but if any of the cancerous cells remain, the patient is still at risk. This work investigates the ability of high aspect ratio nanoparticles to both heal injured tissue and attenuate cancer cells' aggression. To assess different particles' utility, carbon nanoparticles were evaluated in a fibroblast and collagen gel model of wound contraction, then polymeric nanoparticles were synthesized and tested similarly. The carbon particles, multi-walled nanotubes (MWNT) in particular, performed the best, strongly inhibiting pathological wound contraction, increasing cell viability, and decreasing reactive oxygen species. Later, carbon nanoparticle coatings with or without collagen were tested with breast cancer cells to assess adhesion, migration, and E-cadherin expression of the cells. The collagen-MWNT coatings were able to increase cancer cell adhesion to their substrate, decrease migration, increase E-cadherin expression, and also increase autophagy. The coatings effected all these changes without increasing proliferation of the cancer cells or affecting non-tumorigenic breast cells. To examine how these two sets of results might act together, co-cultures were then created with both fibroblasts and cancer cells in collagen gels with or without MWNT. The cells' movement and matrix metalloproteinase (MMP) expression were measured to gauge the cells' interaction in that environment, as fibroblasts can encourage or suppress metastasis depending on their behavior. The MWNT were able to decrease cancer cell movement, particularly their invasion into the gel, and selectively promote cancer cell death without harming the non-tumorigenic cells. They also decreased MMP expression. Finally, early in vivo work was undertaken to determine how the collagen-nanoparticle gels are able to control cancer in

  7. Occupational causes of constrictive bronchiolitis

    PubMed Central

    Kreiss, Kathleen

    2015-01-01

    Purpose of review New literature from 2009 to 2012 regarding occupational constrictive bronchiolitis challenges textbook descriptions of this disease, formerly thought to be limited to fixed airflow limitation arising in the wake of accidental overexposure to noxious chemicals. Indolent evolution of dyspnea without a recognized hazardous exposure is a more common presentation. Recent findings Biopsy-confirmed case series of constrictive bronchiolitis from US soldiers, Iranian survivors of sulfur mustard gassing, hospital-based studies, and flavoring-related cases document that indolent constrictive bronchiolitis cases can have normal spirometry or either restrictive or obstructive abnormalities. High-resolution computerized tomography studies can be normal or reflect air-trapping and mosaic attenuation on expiratory films. Thus, in the absence of noninvasive abnormalities, the diagnosis in dyspneic patients may require thoracoscopic biopsy in settings in which exposure risk has not been recognized. Many workers with occupational constrictive bronchiolitis stabilize with cessation of exposures causing bronchiolar epithelial necrosis. Summary Clinicians need a high index of suspicion for constrictive bronchiolitis in young patients with rapidly progressing exertional dyspnea, regardless of spirometric and radiologic findings. Identification of novel causes and exposure-response relations for known causes are needed to provide guidance for protecting workers at risk for this largely irreversible lung disease. PMID:23407121

  8. Intravenous transplantation of mouse embryonic stem cells attenuates demyelination in an ICR outbred mouse model of demyelinating diseases

    PubMed Central

    Pringproa, Kidsadagon; Sathanawongs, Anucha; Khamphilai, Chananthida; Sukkarinprom, Sarocha; Oranratnachai, Apichart

    2016-01-01

    Induction of demyelination in the central nervous system (CNS) of experimental mice using cuprizone is widely used as an animal model for studying the pathogenesis and treatment of demyelination. However, different mouse strains used result in different pathological outcomes. Moreover, because current medicinal treatments are not always effective in multiple sclerosis patients, so the study of exogenous cell transplantation in an animal model is of great importance. The aims of the present study were to establish an alternative ICR outbred mouse model for studying demyelination and to evaluate the effects of intravenous cell transplantation in the present developed mouse model. Two sets of experiments were conducted. Firstly, ICR outbred and BALB/c inbred mice were fed with 0.2% cuprizone for 6 consecutive weeks; then demyelinating scores determined by luxol fast blue stain or immunolabeling with CNPase were evaluated. Secondly, attenuation of demyelination in ICR mice by intravenous injection of mES cells was studied. Scores for demyelination in the brains of ICR mice receiving cell injection (mES cells-injected group) and vehicle (sham-inoculated group) were assessed and compared. The results showed that cuprizone significantly induced demyelination in the cerebral cortex and corpus callosum of both ICR and BALB/c mice. Additionally, intravenous transplantation of mES cells potentially attenuated demyelination in ICR mice compared with sham-inoculated groups. The present study is among the earliest reports to describe the cuprizone-induced demyelination in ICR outbred mice. Although it remains unclear whether mES cells or trophic effects from mES cells are the cause of enhanced remyelination, the results of the present study may shed some light on exogenous cell therapy in central nervous system demyelinating diseases. PMID:27904491

  9. Mild Hypothermia Attenuates the Anesthetic Isoflurane-Induced Cytotoxicity

    PubMed Central

    Li, Cheng; Dong, Yuanlin; Chen, Dan; Xie, Zhongcong; Zhang, Yiying

    2017-01-01

    The commonly used inhalation anesthetic isoflurane has been reported to induce DNA damage and cytotoxicity. However, the methods to attenuate these effects remain largely to be determined. Mild hypothermia has neuroprotective effects. We therefore set out to assess whether mild hypothermia could protect the isoflurane-induced DNA damage and cytotoxicity. Moreover, we investigated the underlying mechanisms by assessing the effects of mild hypothermia on the isoflurane-induced changes in ATP levels. H4 human neuroglioma cells were treated with 2% isoflurane for 3 or 6 h with and without mild hypothermia (35°C). We assessed the cell viability by using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and lactate dehydrogenase (LDH) assay. We determined DNA damage by measuring levels of phosphorylation of the histone protein H2A variant X at Ser139 (γH2A.X), the marker of DNA damage. We also measured ATP levels in the cells. Here we showed that the treatment with 2% isoflurane for 6 h induced cytotoxicity and DNA damage in the cells. Moreover, the treatment with 2% isoflurane for 3 h decreased ATP levels without inducing cytotoxicity. Mild hypothermia attenuated the isoflurane-induced cytotoxicity, DNA damage, and ATP reduction in the cells. Taken together, these data suggest that the isoflurane-induced reduction in ATP levels occurred before the isoflurane-induced cytotoxicity. Isoflurane may induce DNA damage and cause cytotoxicity through reducing ATP levels. Mild hypothermia would ameliorate isoflurane-induced DNA damage and cytotoxicity by attenuating the isoflurane-induced reduction in ATP levels. These pilot studies have established a system and will promote the future investigations of anesthesia neurotoxicity. PMID:28228717

  10. Mild Hypothermia Attenuates the Anesthetic Isoflurane-Induced Cytotoxicity.

    PubMed

    Li, Cheng; Dong, Yuanlin; Chen, Dan; Xie, Zhongcong; Zhang, Yiying

    2017-01-01

    The commonly used inhalation anesthetic isoflurane has been reported to induce DNA damage and cytotoxicity. However, the methods to attenuate these effects remain largely to be determined. Mild hypothermia has neuroprotective effects. We therefore set out to assess whether mild hypothermia could protect the isoflurane-induced DNA damage and cytotoxicity. Moreover, we investigated the underlying mechanisms by assessing the effects of mild hypothermia on the isoflurane-induced changes in ATP levels. H4 human neuroglioma cells were treated with 2% isoflurane for 3 or 6 h with and without mild hypothermia (35°C). We assessed the cell viability by using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and lactate dehydrogenase (LDH) assay. We determined DNA damage by measuring levels of phosphorylation of the histone protein H2A variant X at Ser139 (γH2A.X), the marker of DNA damage. We also measured ATP levels in the cells. Here we showed that the treatment with 2% isoflurane for 6 h induced cytotoxicity and DNA damage in the cells. Moreover, the treatment with 2% isoflurane for 3 h decreased ATP levels without inducing cytotoxicity. Mild hypothermia attenuated the isoflurane-induced cytotoxicity, DNA damage, and ATP reduction in the cells. Taken together, these data suggest that the isoflurane-induced reduction in ATP levels occurred before the isoflurane-induced cytotoxicity. Isoflurane may induce DNA damage and cause cytotoxicity through reducing ATP levels. Mild hypothermia would ameliorate isoflurane-induced DNA damage and cytotoxicity by attenuating the isoflurane-induced reduction in ATP levels. These pilot studies have established a system and will promote the future investigations of anesthesia neurotoxicity.

  11. Compensation method for attenuated planar laser images of optically dense sprays

    NASA Astrophysics Data System (ADS)

    Abu-Gharbieh, Rafeef; Persson, John L.; Försth, Michael; Rosén, Arne; Karlström, Anders; Gustavsson, Tomas

    2000-03-01

    We present a method for compensating laser attenuation in optically dense sprays, in particular for use in combustion engine research. Images of the fuel sprays are produced by planar laser imaging, where Mie scattered light from a cross section of the spray is imaged onto a CCD camera. The compensation scheme is based on the Beer Lambert law, which is used here to sum up the loss of light along the path of the laser in the image, and to compensate iteratively, pixel by pixel, for this loss.

  12. Digital holographic microscope with low-frequency attenuation filter for position measurement of a nanoparticle.

    PubMed

    Pham, Quang Duc; Kusumi, Yuichi; Hasegawa, Satoshi; Hayasaki, Yoshio

    2012-10-01

    We propose a new method for three-dimensional (3D) position measurement of nanoparticles using an in-line digital holographic microscope. The method improves the signal-to-noise ratio of the amplitude of the interference fringes to achieve higher accuracy in the position measurement by increasing weak scattered light from a nanoparticle relative to the reference light by using a low spatial frequency attenuation filter. We demonstrated the improvements of signal-to-noise ratio of the optical system and contrast of the interference fringes, allowing the 3D positions of nanoparticles to be determined more precisely.

  13. A Guide to the Librarian's Responsibility in Achieving Quality in Lighting and Ventilation.

    ERIC Educational Resources Information Center

    Mason, Ellsworth

    1967-01-01

    Quality, not intensity, is the keystone to good library lighting. The single most important problem in lighting is glare caused by extremely intense centers of light. Multiple interfiling of light rays is a factor required in library lighting. A fixture that diffuses light well is basic when light emerges from the fixture. It scatters widely,…

  14. Knockout of Ccr2 alleviates photoreceptor cell death in rodent retina exposed to chronic blue light.

    PubMed

    Hu, Zizhong; Zhang, Yi; Wang, Junling; Mao, Pingan; Lv, Xuehua; Yuan, Songtao; Huang, Zhengru; Ding, Yuzhi; Xie, Ping; Liu, Qinghuai

    2016-11-10

    Age-related macular degeneration (AMD), the leading cause of visual loss after the age of 60 years, is a degenerative retinal disease involving a variety of environmental and hereditary factors. Although it has been implicated that immune system is involved in the disease progression, the exact role that microglia has is still unclear. Here we demonstrated that knockout of Ccr2 gene could alleviate photoreceptor cell death in mice retinas exposed to chronic blue light. In Ccr2(-/-) mice, a damaged microglia recruitment was shown in retina and this could protect the visual function in electroretinogram and alleviate the photoreceptor apoptosis, which thus helped attenuate the blue light-induced retinopathy. We further found an increased co-location of NLRP3, Iba-1, and IL-1β in fluorescence and a concomitant increased protein expression of NLRP3, caspase-1, and IL-1β in western blotting in chronic blue light-induced retinopathy. Moreover, the activation of microglia and their cellular NLRP3 inflammasomes occurred as an earlier step before the structural and functional damage of the mice retinas, which collectively supported that microglial NLRP3 inflammasome might be the key to the chronic blue light-induced retinopathy.

  15. BLAM (Benthic Light Availability Model): A Proposed Model of Hydrogeomorphic Controls on Light in Rivers

    NASA Astrophysics Data System (ADS)

    Julian, J. P.; Doyle, M. W.; Stanley, E. H.

    2006-12-01

    Light is vital to the dynamics of aquatic ecosystems. It drives photosynthesis and photochemical reactions, affects thermal structure, and influences behavior of aquatic biota. Despite the fundamental role of light to riverine ecosystems, light studies in rivers have been mostly neglected because i) boundary conditions (e.g., banks, riparian vegetation) make ambient light measurements difficult, and ii) the optical water quality of rivers is highly variable and difficult to characterize. We propose a benthic light availability model (BLAM) that predicts the percent of incoming photosynthetically active radiation (PAR) available at the river bed. BLAM was developed by quantifying light attenuation of the five hydrogeomorphic controls that dictate riverine light availability: topography, riparian vegetation, channel geometry, optical water quality, and water depth. BLAM was calibrated using hydrogeomorphic data and light measurements from two rivers: Deep River - a 5th-order, turbid river in central North Carolina, and Big Spring Creek - a 2nd-order, optically clear stream in central Wisconsin. We used a series of four PAR sensors to measure i) above-canopy PAR, ii) PAR above water surface, iii) PAR below water surface, and iv) PAR on stream bed. These measurements were used to develop empirical light attenuation coefficients, which were then used in combination with optical water quality measurements, shading analyses, channel surveys, and flow records to quantify the spatial and temporal variability in riverine light availability. Finally, we apply BLAM to the Baraboo River - a 6th-order, 120-mile, unimpounded river in central Wisconsin - in order to characterize light availability along the river continuum (from headwaters to mouth).

  16. Profound defects in pupillary responses to light in TRPM-channel null mice: a role for TRPM channels in non-image-forming photoreception.

    PubMed

    Hughes, Steven; Pothecary, Carina A; Jagannath, Aarti; Foster, Russell G; Hankins, Mark W; Peirson, Stuart N

    2012-01-01

    TRPM1 is a spontaneously active non-selective cation channel that has recently been shown to play an important role in the depolarizing light responses of ON bipolar cells. Consistent with this role, mutations in the TRPM1 gene have been identified as a principal cause of congenital stationary night blindness. However, previous microarray studies have shown that Trpm1 and Trpm3 are acutely regulated by light in the eyes of mice lacking rods and cones (rd/rd cl), a finding consistent with a role in non-image-forming photoreception. In this study we show that pupillary light responses are significantly attenuated in both Trpm1(-/-) and Trpm3(-/-) animals. Trpm1(-/-) mice exhibit a profound deficit in the pupillary response that is far in excess of that observed in mice lacking rods and cones (rd/rd cl) or melanopsin, and cannot be explained by defects in bipolar cell function alone. Immunolocalization studies suggest that TRPM1 is expressed in ON bipolar cells and also a subset of cells in the ganglion cell layer, including melanopsin-expressing photosensitive retinal ganglion cells (pRGCs). We conclude that, in addition to its role in bipolar cell signalling, TRPM1 is involved in non-image-forming responses to light and may perform a functional role within pRGCs. By contrast, TRPM3(-/-) mice display a more subtle pupillary phenotype with attenuated responses under bright light and dim light conditions. Expression of TRPM3 is detected in Muller cells and the ciliary body but is absent from pRGCs, and thus our data support an indirect role for TRPM3 in pupillary light responses.

  17. Visible light exposure induces VEGF gene expression through activation of retinoic acid receptor-alpha in retinoblastoma Y79 cells.

    PubMed

    Akiyama, Hideo; Tanaka, Toru; Doi, Hiroshi; Kanai, Hiroyoshi; Maeno, Toshitaka; Itakura, Hirotaka; Iida, Tomohiro; Kimura, Yasutaka; Kishi, Shoji; Kurabayashi, Masahiko

    2005-04-01

    Neovascularization of the retina and choroids is the pathological hallmark of many retinopathies, but its molecular mechanisms remain unclear. Vascular endothelial growth factor (VEGF), which is induced by hypoxia or cytokines, plays a critical role in the abnormal growth of blood vessels. In this study, we report that visible light exposure induces VEGF gene expression in retinoblastoma Y79 cells. Fluorescent light exposure (700 lux, wavelength 400 approximately 740 nm) caused a significant increase in VEGF transcripts and protein levels. Such an induction seemed to be specific to certain cells, including photoreceptor cells, because light-induced VEGF expression was not observed in either nontransformed cells, such as retinal pigment epithelium cells, and bovine aortic endothelial cells or transformed cells, such as CV-1 and HepG2 cells. Pertussis toxin and guanosine 5'-[beta-thio]diphosphate, specific inhibitors for rhodopsin-associated G protein, blunted this induction. Progressive deletion and site-specific mutation analyses indicate that light stimulation increases VEGF promoter activity through G+C-rich sequence, which is proven by Sp1 binding sites by supershift assays. Electrophoretic mobility shift assays show that light stimulation increases Sp1 binding. Synthetic retinoic acid receptor-alpha (RARalpha) antagonist completely abrogated light-mediated increase in VEGF expression. Transfection of Y79 cells with dominant negative mutant of RARalpha significantly attenuated the light-mediated induction of VEGF promoter activity. In conclusion, our data indicate that light exposure increases VEGF expression through the mechanisms involving activation of Sp1 and RARalpha signaling in Y79 cells. This study provides new insight into the role of visible light in the transcription and induction of VEGF gene expression.

  18. [The dangers of blue light: True story!].

    PubMed

    Renard, G; Leid, J

    2016-05-01

    The dangers of the blue light are the object of numerous publications, for both the scientific community and the general public. The new prolific development of light sources emitting potentially toxic blue light (415-455nm) ranges from LED (Light Emitting Diodes) lamps for interior lighting to television screens, computers, digital tablets and smartphones using OLED (Organic Light Emitting Diode) or AMOLED (Active-Matrix Organic Light Emitting Diode) technology. First we will review some technical terms and the main characteristics of light perceived by the human eye. Then we will discuss scientific proof of the toxicity of blue light to the eye, which may cause cataract or macular degeneration. Analysis of the light spectra of several light sources, from natural light to LED lamps, will allow us to specify even better the dangers related to each light source. LED lamps, whether used as components for interior lighting or screens, are of concern if they are used for extended viewing times and at short distance. While we can protect ourselves from natural blue light by wearing colored glasses which filter out, on both front and back surfaces, the toxic wavelengths, it is more difficult to protect oneself from LED lamps in internal lighting, the use of which should be restricted to "white warmth" lamps (2700K). As far as OLED or AMOLED screens are concerned, the only effective protection consists of using them occasionally and only for a short period of time.

  19. Electrically tunable hot-silicon terahertz attenuator

    SciTech Connect

    Wang, Minjie; Vajtai, Robert; Ajayan, Pulickel M.; Kono, Junichiro

    2014-10-06

    We have developed a continuously tunable, broadband terahertz attenuator with a transmission tuning range greater than 10{sup 3}. Attenuation tuning is achieved electrically, by simply changing the DC voltage applied to a heating wire attached to a bulk silicon wafer, which controls its temperature between room temperature and ∼550 K, with the corresponding free-carrier density adjusted between ∼10{sup 11 }cm{sup −3} and ∼10{sup 17 }cm{sup −3}. This “hot-silicon”-based terahertz attenuator works most effectively at 450–550 K (corresponding to a DC voltage variation of only ∼7 V) and completely shields terahertz radiation above 550 K in a frequency range of 0.1–2.5 THz. Both intrinsic and doped silicon wafers were tested and demonstrated to work well as a continuously tunable attenuator. All behaviors can be understood quantitatively via the free-carrier Drude model taking into account thermally activated intrinsic carriers.

  20. Mycoplasma gallisepticum: Control by live attenuated vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercially available attenuated strains of Mycoplasma gallisepticum (MG) are commonly used within the layer industry to control MG-induced mycoplasmosis. Among these are two live MG vaccines derived from the moderately pathogenic MG “chick F” strain. In the present study, the commercially availa...

  1. Infrared Attenuation Of Thallium Bromoiodide Fibers

    NASA Technical Reports Server (NTRS)

    Goebel, John; Magilavy, Beryl

    1988-01-01

    Report presents measurements of attenuation of infrared signals in unclad 381-micrometer-diameter optical fibers of thallium bromoiodide. Measurements of attentuation in TI(Br,I) fibers in wavelength ranges of 1.2 to 3.4 micrometer and 3 to 11 micrometer compare with those of two other groups of researchers.

  2. Touch Attenuates Infants' Physiological Reactivity to Stress

    ERIC Educational Resources Information Center

    Feldman, Ruth; Singer, Magi; Zagoory, Orna

    2010-01-01

    Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal…