Excitonic Effects and Optical Absorption Spectrum of Doped Graphene

NASA Astrophysics Data System (ADS)

Jornada, Felipe; Deslippe, Jack; Louie, Steven

2012-02-01

First-principles calculations based on the GW-Bethe-Salpeter Equation (GW-BSE) approach and subsequent experiments have shown large excitonic effects in the optical absorbance of graphene. Here we employ the GW-BSE formalism to probe the effects of charge carrier doping and of having an external electric field on the absorption spectrum of graphene. We show that the absorbance peak due to the resonant exciton exhibits systematic changes in both its position and profile when graphene is gate doped by carriers, in excellent agreement to very recent measurementsootnotetextTony F. Heinz, private communications.. We analyze the various contributions to these changes in the absorption spectrum, such as the effects of screening by carriers to the quasiparticle energies and electron-hole interactions. This work was supported by National Science Foundation Grant No. DMR10-1006184, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and the U.S. DOD - Office of Naval Research under RTC Grant No. N00014-09-1-1066. Computer time was provided by NERSC.

Model Order Reduction Algorithm for Estimating the Absorption Spectrum

SciTech Connect

Van Beeumen, Roel; Williams-Young, David B.; Kasper, Joseph M.

The ab initio description of the spectral interior of the absorption spectrum poses both a theoretical and computational challenge for modern electronic structure theory. Due to the often spectrally dense character of this domain in the quantum propagator’s eigenspectrum for medium-to-large sized systems, traditional approaches based on the partial diagonalization of the propagator often encounter oscillatory and stagnating convergence. Electronic structure methods which solve the molecular response problem through the solution of spectrally shifted linear systems, such as the complex polarization propagator, offer an alternative approach which is agnostic to the underlying spectral density or domain location. This generality comesmore » at a seemingly high computational cost associated with solving a large linear system for each spectral shift in some discretization of the spectral domain of interest. In this work, we present a novel, adaptive solution to this high computational overhead based on model order reduction techniques via interpolation. Model order reduction reduces the computational complexity of mathematical models and is ubiquitous in the simulation of dynamical systems and control theory. The efficiency and effectiveness of the proposed algorithm in the ab initio prediction of X-ray absorption spectra is demonstrated using a test set of challenging water clusters which are spectrally dense in the neighborhood of the oxygen K-edge. On the basis of a single, user defined tolerance we automatically determine the order of the reduced models and approximate the absorption spectrum up to the given tolerance. We also illustrate that, for the systems studied, the automatically determined model order increases logarithmically with the problem dimension, compared to a linear increase of the number of eigenvalues within the energy window. Furthermore, we observed that the computational cost of the proposed algorithm only scales quadratically with respect

The widetilde{A}←widetilde{X} ABSORPTION SPECTRUM OF 2-NITROOXYBUTYL PEROXY RADICAL

NASA Astrophysics Data System (ADS)

Eddingsaas, Nathan; Takematsu, Kana; Okumura, Mitchio

2009-06-01

The nitrate radical is an important atmospheric oxidant in the nighttime sky. Nitrate radicals react by addition to alkenes, and in the presence of oxygen form nitrooxyalkyl peroxy radicals. The peroxy radical formed from the reaction of 2-butene, nitrate radical, and oxygen was detected by cavity ringdown spectroscopy (CRDS) via its widetilde{A}←widetilde{X} electronic absorption spectrum. The widetilde{A}←widetilde{X} electronic transition is a bound-bound transition with enough structure to distinguish between different peroxy radicals as well as different conformers of the same peroxy radical. Two conformers of the nitrooxybutyl peroxy radical have been observed; the absorption features are red shifted from the same absorption features of sec-butyl peroxy radical. Calculations on the structure of nitrooxyalkyl peroxy radicals and general trends of the position of the widetilde{A}←widetilde{X} absorption transitions have also been performed and compared to those of unsubstituted peroxy radicals.

Research on filling process of fuel and oxidant during detonation based on absorption spectrum technology

NASA Astrophysics Data System (ADS)

Lv, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

2014-12-01

Research on detonation process is of great significance for the control optimization of pulse detonation engine. Based on absorption spectrum technology, the filling process of fresh fuel and oxidant during detonation is researched. As one of the most important products, H2O is selected as the target of detonation diagnosis. Fiber distributed detonation test system is designed to enable the detonation diagnosis under adverse conditions in detonation process. The test system is verified to be reliable. Laser signals at different working frequency (5Hz, 10Hz and 20Hz) are detected. Change of relative laser intensity in one detonation circle is analyzed. The duration of filling process is inferred from the change of laser intensity, which is about 100~110ms. The peak of absorption spectrum is used to present the concentration of H2O during the filling process of fresh fuel and oxidant. Absorption spectrum is calculated, and the change of absorption peak is analyzed. Duration of filling process calculated with absorption peak consisted with the result inferred from the change of relative laser intensity. The pulse detonation engine worked normally and obtained the maximum thrust at 10Hz under experiment conditions. The results are verified through H2O gas concentration monitoring during detonation.

Photoacoustic Monitoring of Absorption Spectrum During the Dehydration Process of pasilla Chili Pepper

NASA Astrophysics Data System (ADS)

Zendejas-Leal, Blanca Estela; Barrientos-Sotelo, Víctor Rodrigo; Cano-Casas, Rogelio; Alvarado-Noguez, Margarita Lizeth; Hernández-Rosas, Juan; Cruz-Orea, Alfredo

2018-07-01

In this work, the optical absorption spectrum of peppers was monitored by phase-resolved photoacoustic spectroscopy during a dehydration process based on hot-air drying, yielding simultaneous information about changes in the exocarp and mesocarp. Our results show that between all of the dehydration processes of green Capsicum annuum L. variety pasilla peppers, only very small changes occur in the different phase angles, which has been correlated with the small changes in the exocarp thickness. The phase-resolved spectra of mesocarp show more clearly the evolution of the carotenoid compounds with respect to the optical absorption spectrum without phase resolving, due to the last spectrum having a band broadening in that region with more signals convolved. We have shown that not only do the ripened chili peppers produce new carotenoid compounds, but also we are probing that the dehydration process, beginning with the green stage, preserves the nutrimental content, similar to changes that occur in the natural ripening process.

The energy spectrum and the optical absorption spectrum of C{sub 60} fullerene within the Hubbard model

SciTech Connect

Silant’ev, A. V., E-mail: kvvant@rambler.ru

2015-10-15

Anticommutator Green’s functions and the energy spectrum of C{sub 60} fullerene are calculated in the approximation of static fluctuations within the Hubbard model. On the basis of this spectrum, an interpretation is proposed for the experimentally observed optical absorption bands of C{sub 60} fullerene. The parameters of C{sub 60} fullerene that characterize it within the Hubbard model are calculated by the optical absorption spectrum.

Tunable Spectrum Selectivity for Multiphoton Absorption with Enhanced Visible Light Trapping in ZnO Nanorods.

PubMed

Tan, Kok Hong; Lim, Fang Sheng; Toh, Alfred Zhen Yang; Zheng, Xia-Xi; Dee, Chang Fu; Majlis, Burhanuddin Yeop; Chai, Siang-Piao; Chang, Wei Sea

2018-04-17

Observation of visible light trapping in zinc oxide (ZnO) nanorods (NRs) correlated to the optical and photoelectrochemical properties is reported. In this study, ZnO NR diameter and c-axis length respond primarily at two different regions, UV and visible light, respectively. ZnO NR diameter exhibits UV absorption where large ZnO NR diameter area increases light absorption ability leading to high efficient electron-hole pair separation. On the other hand, ZnO NR c-axis length has a dominant effect in visible light resulting from a multiphoton absorption mechanism due to light reflection and trapping behavior in the free space between adjacent ZnO NRs. Furthermore, oxygen vacancies and defects in ZnO NRs are associated with the broad visible emission band of different energy levels also highlighting the possibility of the multiphoton absorption mechanism. It is demonstrated that the minimum average of ZnO NR c-axis length must satisfy the linear regression model of Z p,min = 6.31d to initiate the multiphoton absorption mechanism under visible light. This work indicates the broadening of absorption spectrum from UV to visible light region by incorporating a controllable diameter and c-axis length on vertically aligned ZnO NRs, which is important in optimizing the design and functionality of electronic devices based on light absorption mechanism. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Absorption line profiles in a companion spectrum of a mass losing cool supergiant

NASA Technical Reports Server (NTRS)

Rodrigues, Liliya L.; Boehm-Vitense, Erika

1990-01-01

Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

RETRACTED: Theoretical study of electronic properties and isotope effects in the UV absorption spectrum of disulfur

NASA Astrophysics Data System (ADS)

Sarka, Karolis; Danielache, Sebastian O.; Kondorskiy, Alexey; Nanbu, Shinkoh

2017-05-01

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy) This article has been retracted at the request of the Authors because of a large amount of errors caused by incorrect interpretation of the potential energy curve boundaries by the data processing functions in their close-coupling algorithm, producing incorrect wavefunctions for the continuum region in the absorption spectrum. The spectrum calculated using the incorrect wavefunctions introduced periodic fluctuation in the absorption cross-section seen in the original article, which results in erroneous isotopic fractionation values. The updated spectra calculated after fixing the issues features a smooth continuum band, removing all false artifacts from isotopic effect analysis, producing significantly different results from the ones in this original article. The authors will submit the corrected data in a new article.

Sodium Absorption from the Exoplanetary Atmosphere of HD 189733b Detected in the Optical Transmission Spectrum

NASA Astrophysics Data System (ADS)

Redfield, Seth; Endl, Michael; Cochran, William D.; Koesterke, Lars

2008-01-01

We present the first ground-based detection of sodium absorption in the transmission spectrum of an extrasolar planet. Absorption due to the atmosphere of the extrasolar planet HD 189733b is detected in both lines of the Na I doublet. High spectral resolution observations were taken of 11 transits with the High Resolution Spectrograph (HRS) on the 9.2 m Hobby-Eberly Telescope (HET). The Na I absorption in the transmission spectrum due to HD 189733b is (- 67.2 +/- 20.7) × 10-5 deeper in the "narrow" spectral band that encompasses both lines relative to adjacent bands. The 1 σ error includes both random and systematic errors, and the detection is >3 σ. This amount of relative absorption in Na I for HD 189733b is ~3 times larger than that detected for HD 209458b by Charbonneau et al. (2002) and indicates that these two hot Jupiters may have significantly different atmospheric properties. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Strong water absorption in the dayside emission spectrum of the planet HD 189733b.

PubMed

Grillmair, Carl J; Burrows, Adam; Charbonneau, David; Armus, Lee; Stauffer, John; Meadows, Victoria; van Cleve, Jeffrey; von Braun, Kaspar; Levine, Deborah

2008-12-11

Recent observations of the extrasolar planet HD 189733b did not reveal the presence of water in the emission spectrum of the planet. Yet models of such 'hot-Jupiter' planets predict an abundance of atmospheric water vapour. Validating and constraining these models is crucial to understanding the physics and chemistry of planetary atmospheres in extreme environments. Indications of the presence of water in the atmosphere of HD 189733b have recently been found in transmission spectra, where the planet's atmosphere selectively absorbs the light of the parent star, and in broadband photometry. Here we report the detection of strong water absorption in a high-signal-to-noise, mid-infrared emission spectrum of the planet itself. We find both a strong downturn in the flux ratio below 10 microm and discrete spectral features that are characteristic of strong absorption by water vapour. The differences between these and previous observations are significant and admit the possibility that predicted planetary-scale dynamical weather structures may alter the emission spectrum over time. Models that match the observed spectrum and the broadband photometry suggest that heat redistribution from the dayside to the nightside is weak. Reconciling this with the high nightside temperature will require a better understanding of atmospheric circulation or possible additional energy sources.

Analysis of gaseous ammonia (NH3) absorption in the visible spectrum of Jupiter

NASA Astrophysics Data System (ADS)

Irwin, Patrick G. J.; Bowles, Neil; Braude, Ashwin S.; Garland, Ryan; Calcutt, Simon

2018-03-01

Observations of the visible/near-infrared reflectance spectrum of Jupiter have been made with the Very Large Telescope (VLT) Multi Unit Spectroscopic Explorer (MUSE) instrument in the spectral range 0.48-0.93 μm in support of the NASA/Juno mission. These spectra contain spectral signatures of gaseous ammonia (NH3), whose abundance above the cloud tops can be determined if we have reliable information on its absorption spectrum. While there are a number of sources of NH3 absorption data in this spectral range, they cover small sub-ranges, which do not necessarily overlap and have been determined from a variety of sources. There is thus considerable uncertainty regarding the consistency of these different sources when modelling the reflectance of the entire visible/near-IR range. In this paper we analyse the VLT/MUSE observations of Jupiter to determine which sources of ammonia absorption data are most reliable. We find that the band model coefficients of Bowles et al. (2008) provide, in general, the best combination of reliability and wavelength coverage over the MUSE range. These band data appear consistent with ExoMOL ammonia line data of Yurchenko et al. (2011), at wavelengths where they overlap, but these latter data do not cover the ammonia absorption bands at 0.79 and 0.765 μm, which are prominent in our MUSE observations. However, we find the band data of Bowles et al. (2008) are not reliable at wavelengths less than 0.758 μm. At shorter wavelengths we find the laboratory observations of Lutz and Owen (1980) provide a good indication of the position and shape of the ammonia absorptions near 0.552 μm and 0.648 μm, but their absorption strengths appear inconsistent with the band data of Bowles et al. (2008) at longer wavelengths. Finally, we find that the line data of the 0.648 μm absorption band of Giver et al. (1975) are not suitable for modelling these data as they account for only 17% of the band absorption and cannot be extended reliably to the cold

A structure preserving Lanczos algorithm for computing the optical absorption spectrum

SciTech Connect

Shao, Meiyue; Jornada, Felipe H. da; Lin, Lin

2016-11-16

We present a new structure preserving Lanczos algorithm for approximating the optical absorption spectrum in the context of solving full Bethe-Salpeter equation without Tamm-Dancoff approximation. The new algorithm is based on a structure preserving Lanczos procedure, which exploits the special block structure of Bethe-Salpeter Hamiltonian matrices. A recently developed technique of generalized averaged Gauss quadrature is incorporated to accelerate the convergence. We also establish the connection between our structure preserving Lanczos procedure with several existing Lanczos procedures developed in different contexts. Numerical examples are presented to demonstrate the effectiveness of our Lanczos algorithm.

UV absorption spectrum and photodissociation channels of the simplest Criegee intermediate (CH2OO).

PubMed

Dawes, Richard; Jiang, Bin; Guo, Hua

2015-01-14

The lowest-lying singlet states of the simplest Criegee intermediate (CH2OO) have been characterized along the O-O dissociation coordinate using explicitly correlated MRCI-F12 electronic structure theory and large active spaces. It is found that a high-level treatment of dynamic electron-correlation is essential to accurately describe these states. A significant well on the B-state is identified at the MRCI-F12 level with an equilibrium structure that differs substantially from that of the ground X-state. This well is presumably responsible for the apparent vibrational structure in some experimental UV absorption spectra, analogous to the structured Huggins band of the iso-electronic ozone. The B-state potential in the Franck-Condon region is sufficiently accurate that an absorption spectrum calculated with a one-dimensional model agrees remarkably well with experiment.

Investigations on the 1.7 micron residual absorption feature in the vegetation reflection spectrum

NASA Technical Reports Server (NTRS)

Verdebout, J.; Jacquemoud, S.; Andreoli, G.; Hosgood, B.; Sieber, A.

1993-01-01

The detection and interpretation of the weak absorption features associated with the biochemical components of vegetation is of great potential interest to a variety of applications ranging from classification to global change studies. This recent subject is also challenging because the spectral signature of the biochemicals is only detectable as a small distortion of the infrared spectrum which is mainly governed by water. Furthermore, the interpretation is complicated by complexity of the molecules (lignin, cellulose, starch, proteins) which contain a large number of different and common chemical bonds. In this paper, we present investigations on the absorption feature centered at 1.7 micron; these were conducted both on AVIRIS data and laboratory reflectance spectra of leaves.

Computational study of the absorption spectrum of defected ZnS nanoparticles

NASA Astrophysics Data System (ADS)

Michos, F. I.; Sigalas, M. M.

2018-04-01

Energy levels and absorption spectra of defected ZnS nanoparticles (NPs) were calculated with Density Functional Theory (DFT) and Time Dependent DFT. Several types of defects were examined such as vacancies and substitutions. NPs with S vacancies were found to have their absorption spectra moved to lower energies well inside the visible spectrum with significantly high oscillator strength. Also, NPs with substitution of S atoms with Cl, Br, or I showed significant absorption. In general, this type of defect moves the absorption spectra in lower energies, thus bringing the absorption edge into the visible spectrum, while the unperturbed NPs have absorption edges in the UV region. In addition, ZnS NPs are made from more abundant and less toxic elements than the more commonly used CdSe NPs. For that reason, they may find significant applications in solar cells and other photonic applications, as well as in biosensing applications as biomarkers.

Electronic absorption spectrum of copper-doped magnesium potassium phosphate hexahydrate

NASA Astrophysics Data System (ADS)

Rao, S. N.; Sivaprasad, P.; Reddy, Y. P.; Rao, P. S.

1992-04-01

The optical absorption and EPR spectra of magnesium potassium phosphate hexahydrate (MPPH) doped with copper ions are recorded both at room and liquid nitrogen temperatures. The spectrum is characteristic of Cu2+ in tetragonal symmetry. The spin-Hamiltonian parameters and molecular orbital coefficients are evaluated. A correlation between EPR and optical absorption studies is drawn.

The Mean Metal-line Absorption Spectrum of Damped Ly α Systems in BOSS

SciTech Connect

Mas-Ribas, Lluís; Miralda-Escudé, Jordi; Pérez-Ràfols, Ignasi

We study the mean absorption spectrum of the Damped Ly α (DLA) population at z ∼ 2.6 by stacking normalized, rest-frame-shifted spectra of ∼27,000 DLA systems from the DR12 of the Baryon Oscillation Spectroscopic Survey (BOSS)/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in five intervals of DLA hydrogen column density, five intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with N {sub H} {sub i}, whereas for high-ionization lines the increase is much weaker.more » The mean metal line equivalent widths decrease by a factor ∼1.1–1.5 from z ∼ 2.1 to z ∼ 3.5, with small or no differences between low- and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to Al iii, S iii, Si iii, C iv, Si iv, N v, and O vi. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species N i, Zn ii, C ii*, Fe iii, and S iv. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available.« less

Temperature dependence of the ClONO{sub 2} UV absorption spectrum

SciTech Connect

Burkholder, J.B.; Talukdar, R.K.; Ravishankara, A.R.

1994-04-01

The temperature dependence of the ClONO{sub 2} absorption spectrum has been measured between 220 and 298 K and between 195 and 430 nm using a diode array spectrometer. The absorption cross sections were determined using both: (1) absolute pressure measurements at 296 K and (2) measurements at various temperatures relative to 296 K using a dual absorption cell arrangement. The temperature dependence of the ClONO{sub 2} absorption spectrum shows very broad structure. The amplitude of the temperature dependence relative to that at 296 K is weak at short wavelengths, < 2% at 215 nm and 220 K, but significant atmore » the wavelengths important in the stratosphere, {approximately} 30% at 325 nm and 220 K. The authors ClONO{sub 2} absorption cross section data are in good general agreement with the previous measurements of Molina and Molina.« less

Temperature dependence of the ClONO2 UV absorption spectrum

NASA Technical Reports Server (NTRS)

Burkholder, James B.; Talukdar, Ranajit K.; Ravishankara, A. R.

1994-01-01

The temperature dependence of the ClONO2 absorption spectrum has been measured between 220 and 298 K and between 195 and 430 nm using a diode array spectrometer. The absorption cross sections were determined using both: (1) absolute pressure measurements at 296 K and (2) measurements at various temperatures relative to 296 K using a dual absorption cell arrangement. The temperature dependence of the ClONO2 absorption spectrum shows very broad structure. The amplitude of the temperature dependence relative to that at 296 K is weak at short wavelengths, less than 2% at 215 nm and 220 K, but significant at the wavelengths important in the stratosphere, about 30% at 325 nm and 220 K. Our ClONO2 absorption cross section data are in good general agreement with the previous measurements of Molina and Molina (1979).

Absorption spectrum of the firefly luciferin anion isolated in vacuo.

PubMed

Støchkel, Kristian; Milne, Bruce F; Brøndsted Nielsen, Steen

2011-03-24

The excited-state physics of the firefly luciferin anion depends on its chemical environment, and it is therefore important to establish the intrinsic behavior of the bare ion. Here we report electronic absorption spectra of the anion isolated in vacuo obtained at an electrostatic ion storage ring and an accelerator mass spectrometer where ionic dissociation is monitored on a long time scale (from 33 μs and up to 3 ms) and on a short time scale (0-3 μs), respectively. In the ring experiment the yield of all neutrals (mainly CO(2)) as a function of wavelength was measured whereas in the single pass experiment, the abundance of daughter ions formed after loss of CO(2) was recorded to provide action spectra. We find maxima at 535 and 265 nm, and that the band shape is largely determined by the sampling time interval, which is due to the kinetics of the dissociation process. Calculations at the TD-B3LYP/TZVPP++ level predict maximum absorption at 533 and 275 nm for the carboxylate isomer in excellent agreement with the experimental findings. The phenolate isomer lies higher in energy by 0.22 eV, and also its absorption maximum is calculated to be at 463 nm, which is far away from the experimental value. Our data serve to benchmark future theoretical models for bioluminescence from fireflies.

Complex Resonance Absorption Structure in the X-Ray Spectrum of IRAS 13349+2438

NASA Technical Reports Server (NTRS)

Sako, M.; Kahn, S. M.; Behar, E.; Kaastra, J. S.; Brinkman, A. C.; Boller, Th.; Puchnarewicz, E. M.; Starling, R.; Liedahl, D. A.; Clavel, J.

2000-01-01

The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM - Newton Observatory as part of the Performance Verification program. The spectrum obtained by the Reflection Grating Spectrometer (RGS) exhibits broad (FWHM - 1400 km/s) absorption lines from highly ionized elements including hydrogen- and helium-like carbon, nitrogen, oxygen, and neon, and several iron L - shell ions (Fe XVII - XX). Also shown in the spectrum is the first astrophysical detection of a broad absorption feature around lambda = 16 - 17 A identified as an unresolved transition array (UTA) of 2p - 3d inner-shell absorption by iron M-shell ions in a much cooler medium; a feature that might be misidentified as an O VII edge when observed with moderate resolution spectrometers. No absorption edges are clearly detected in the spectrum. We demonstrate that the RGS spectrum of IRAS 13349+2438 exhibits absorption lines from two distinct regions, one of which is tentatively associated with the medium that produces the optical/UV reddening.

Analysis of the red and green optical absorption spectrum of gas phase ammonia

NASA Astrophysics Data System (ADS)

Zobov, Nikolai F.; Coles, Phillip A.; Ovsyannikov, Roman I.; Kyuberis, Aleksandra A.; Hargreaves, Robert J.; Bernath, Peter F.; Tennyson, Jonathan; Yurchenko, Sergei N.; Polyansky, Oleg L.

2018-04-01

Room temperature NH3 absorption spectra recorded at the Kitt Peak National Solar Observatory in 1980 are analyzed. The spectra cover two regions in the visible: 15,200 - 15,700 cm-1 and 17,950 - 18,250 cm-1. These high overtone rotation-vibration spectra are analyzed using both combination differences and variational line lists. Two variational line lists were computed using the TROVE nuclear motion program: one is based on an ab initio potential energy surface (PES) while the other used a semi-empirical PES. Ab initio dipole moment surfaces are used in both cases. 95 energy levels with J = 1 - 7 are determined from analysis of the experimental spectrum in the 5νNH (red) region and 46 for 6νNH (green) region. These levels span four vibrational bands in each of the two regions, associated with stretching overtones.

Anab InitioStudy of the NH2+Absorption Spectrum

NASA Astrophysics Data System (ADS)

Osmann, Gerald; Bunker, P. R.; Jensen, Per; Kraemer, W. P.

1997-12-01

In a previous publication (1997. P. Jensen,J. Mol. Spectrosc.181,207-214), rotation-vibration energy levels for the electronic ground stateX˜3B1of the amidogen ion, NH2+, were predicted using the MORBID Hamiltonian and computer program with anab initiopotential energy surface. In the present paper we calculate a newab initiopotential energy surface for theX˜3B1state, and we calculateab initiothe potential energy surfaces of theã1A1andb˜1B1excited singlet electronic states (which become degenerate as a1Δ state at linearity). We use the multireference configuration interaction (MR-CI) level of theory with molecular orbital bases that are optimized separately for each state by complete-active-space SCF (CASSCF) calculations. For theX˜state we use the MORBID Hamiltonian and computer program to obtain the rotation-vibration energies. For theãandb˜excited singlet electronic states we calculate the rovibronic energy levels using the RENNER Hamiltonian and computer program. We also calculateab initiothe dipole moment surfaces for theX˜,ã, andb˜electronic states, and the out-of-plane transition moment surface for theb˜←ãelectronic transition. We use this information to simulate absorption spectra withinX˜3B1andã1A1state and of theb˜1B1← ã1A1transition in order to aid in the search for them.

[Signal analysis and spectrum distortion correction for tunable diode laser absorption spectroscopy system].

PubMed

Bao, Wei-Yi; Zhu, Yong; Chen, Jun; Chen, Jun-Qing; Liang, Bo

2011-04-01

In the present paper, the signal of a tunable diode laser absorption spectroscopy (TDLAS) trace gas sensing system, which has a wavelength modulation with a wide range of modulation amplitudes, is studied based on Fourier analysis method. Theory explanation of spectrum distortion induced by laser intensity amplitude modulation is given. In order to rectify the spectrum distortion, a method of synchronous amplitude modulation suppression by a variable optical attenuator is proposed. To validate the method, an experimental setup is designed. Absorption spectrum measurement experiments on CO2 gas were carried out. The results show that the residual laser intensity modulation amplitude of the experimental system is reduced to -0.1% of its original value and the spectrum distortion improvement is 92% with the synchronous amplitude modulation suppression. The modulation amplitude of laser intensity can be effectively reduced and the spectrum distortion can be well corrected by using the given correction method and system. By using a variable optical attenuator in the TDLAS (tunable diode laser absorption spectroscopy) system, the dynamic range requirements of photoelectric detector, digital to analog converter, filters and other aspects of the TDLAS system are reduced. This spectrum distortion correction method can be used for online trace gas analyzing in process industry.

Two-photon absorption spectrum of the photoinitiator Lucirin TPO-L

NASA Astrophysics Data System (ADS)

Mendonca, C. R.; Correa, D. S.; Baldacchini, T.; Tayalia, P.; Mazur, E.

2008-03-01

Two-photon absorption induced polymerization provides a powerful method for the fabrication of intricate three-dimensional microstructures. Recently, Lucirin TPO-L was shown to be a photoinitiator with several advantageous properties for two-photon induced polymerization. Here we measure the two-photon absorption cross-section spectrum of Lucirin TPO-L, which presents a maximum of 1.2 GM at 610 nm. Despite its small two-photon absorption cross-section, it is possible to fabricate excellent microstructures by two-photon polymerization due to the high polymerization quantum yield of Lucirin TPO-L. These results indicate that optimization of the two-photon absorption cross-section is not the only material parameter to be considered when searching for new photoinitiators for microfabrication via two-photon absorption.

Absorption spectrum of a two-level system subjected to a periodic pulse sequence

SciTech Connect

Fotso, H. F.; Dobrovitski, V. V.

We investigate how the quantum control of a two-level system (TLS) coupled to photons can modify and tune the TLS’s photon absorption spectrum. Tuning and controlling the emission and the absorption is of much interest e.g. for the development of efficient interfaces between stationary and flying qubits in modern architectures for quantum computation and quantum communication. We consider the periodic pulse control, where the TLS is subjected to a periodic sequence of the near-resonant Rabi driving pulses, each pulse implementing a 180° rotation. For small inter-pulse delays, the absorption spectrum features a pronounced peak of stimulated emission at the pulsemore » frequency, as well as equidistant satellite peaks with smaller spectral weights. As long as the detuning between the carrier frequency of the driving and the TLS transition frequency remains moderate, this spectral shape shows little change. Therefore, the quantum control allows shifting the absorption peak to a desired position, and locks the absorption peak to the carrier frequency of the driving pulses. Detailed description of the spectrum, and its evolution as a function time, the inter-pulse spacing and the detuning, is presented.« less

Absorption spectrum of a two-level system subjected to a periodic pulse sequence

DOE PAGES

Fotso, H. F.; Dobrovitski, V. V.

2017-06-01

We investigate how the quantum control of a two-level system (TLS) coupled to photons can modify and tune the TLS’s photon absorption spectrum. Tuning and controlling the emission and the absorption is of much interest e.g. for the development of efficient interfaces between stationary and flying qubits in modern architectures for quantum computation and quantum communication. We consider the periodic pulse control, where the TLS is subjected to a periodic sequence of the near-resonant Rabi driving pulses, each pulse implementing a 180° rotation. For small inter-pulse delays, the absorption spectrum features a pronounced peak of stimulated emission at the pulsemore » frequency, as well as equidistant satellite peaks with smaller spectral weights. As long as the detuning between the carrier frequency of the driving and the TLS transition frequency remains moderate, this spectral shape shows little change. Therefore, the quantum control allows shifting the absorption peak to a desired position, and locks the absorption peak to the carrier frequency of the driving pulses. Detailed description of the spectrum, and its evolution as a function time, the inter-pulse spacing and the detuning, is presented.« less

Absorption spectrum of a two-level atom in a bad cavity with injected squeezed vacuum

NASA Astrophysics Data System (ADS)

Zhou, Peng; Swain, S.

1996-02-01

We study the absorption spectrum of a coherently driven two-level atom interacting with a resonant cavity mode which is coupled to a broadband squeezed vacuum through its input-output mirror in the bad cavity limit. We study the modification of the two-photon correlation strength of the injected squeezed vacuum inside the cavity, and show that the equations describing probe absorption in the cavity environment are formally identical to these in free space, but with modified parameters describing the squeezed vacuum. The two photon correlations induced by the squeezed vacuum are always weaker than in free space. We pay particular attention to the spectral behaviour at line centre in the region of intermediate trength driving intensities, where anomalous spectral features such as hole-burning and dispersive profiles are displayed. These unusual spectral features are very sensitive to the squeezing phase and the Rabi frequency of the driving field. We also derive the threshold value of the Rabi frequency which gives rise to the transparency of the probe beam at the driving frequency. When the Rabi frequency is less than the threshold value, the probe beam is absorbed, whilst the probe beam is amplified (without population inversion under certain conditions) when the Rabi frequency is larger than this threshold. The anomalous spectral features all take place in the vicinity of the critical point dividing the different dynamical regimes, probe absorption and amplification, of the atomic radiation. The physical origin of the strong amplification without population inversion, and the feasibility of observing it, are discussed.

Absorption spectrum analysis based on singular value decomposition for photoisomerization and photodegradation in organic dyes

NASA Astrophysics Data System (ADS)

Kawabe, Yutaka; Yoshikawa, Toshio; Chida, Toshifumi; Tada, Kazuhiro; Kawamoto, Masuki; Fujihara, Takashi; Sassa, Takafumi; Tsutsumi, Naoto

2015-10-01

In order to analyze the spectra of inseparable chemical mixtures, many mathematical methods have been developed to decompose them into the components relevant to species from series of spectral data obtained under different conditions. We formulated a method based on singular value decomposition (SVD) of linear algebra, and applied it to two example systems of organic dyes, being successful in reproducing absorption spectra assignable to cis/trans azocarbazole dyes from the spectral data after photoisomerization and to monomer/dimer of cyanine dyes from those during photodegaradation process. For the example of photoisomerization, polymer films containing the azocarbazole dyes were prepared, which have showed updatable holographic stereogram for real images with high performance. We made continuous monitoring of absorption spectrum after optical excitation and found that their spectral shapes varied slightly after the excitation and during recovery process, of which fact suggested the contribution from a generated photoisomer. Application of the method was successful to identify two spectral components due to trans and cis forms of azocarbazoles. Temporal evolution of their weight factors suggested important roles of long lifetimed cis states in azocarbazole derivatives. We also applied the method to the photodegradation of cyanine dyes doped in DNA-lipid complexes which have shown efficient and durable optical amplification and/or lasing under optical pumping. The same SVD method was successful in the extraction of two spectral components presumably due to monomer and H-type dimer. During the photodegradation process, absorption magnitude gradually decreased due to decomposition of molecules and their decaying rates strongly depended on the spectral components, suggesting that the long persistency of the dyes in DNA-complex related to weak tendency of aggregate formation.

Femtosecond time-domain observation of atmospheric absorption in the near-infrared spectrum

NASA Astrophysics Data System (ADS)

Hammond, T. J.; Monchocé, Sylvain; Zhang, Chunmei; Brown, Graham G.; Corkum, P. B.; Villeneuve, D. M.

2016-12-01

As light propagates through a medium, absorption caused by electronic or rovibrational transitions is evident in the transmitted spectrum. The incident electromagnetic field polarizes the medium and the absorption is due to the imaginary part of the linear susceptibility. In the time domain, the field establishes a coherence in the medium that radiates out of phase with the initial field. This coherence can persist for tens of picoseconds in atmospheric molecules such as H2O . We propagate a few-cycle laser pulse centered at 1.8 μ m through the atmosphere and measure the long-lasting molecular coherence in the time domain by high-order harmonic cross correlation. The measured optical free-induction decay of the pulse is compared with a calculation based on the calculated rovibrational spectrum of H2O absorption.

The visible absorption spectrum of NO3 measured by high-resolution Fourier transform spectroscopy

NASA Astrophysics Data System (ADS)

Orphal, J.; Fellows, C. E.; Flaud, P.-M.

2003-02-01

The visible absorption spectrum of the nitrate radical NO3 has been measured using high-resolution Fourier transform spectroscopy. The spectrum was recorded at 294 K using a resolution of 0.6 cm-1 (corresponding to 0.026 nm at 662 nm) and covers the 12600-21500 cm-1 region (465-794 nm). Compared to absorption spectra of NO3 recorded previously, the new data show improvements concerning absolute wavelength calibration (uncertainty 0.02 cm-1), and spectral resolution. A new interpretation and model of the temperature dependence of the strong (0-0) band around 662 nm are proposed. The results are important for long-path tropospheric absorption measurements of NO3 and optical remote sensing of the Earth's atmosphere from space.

The root economics spectrum: divergence of absorptive root strategies with root diameter

NASA Astrophysics Data System (ADS)

Kong, D.; Wang, J.; Kardol, P.; Wu, H.; Zeng, H.; Deng, X.; Deng, Y.

2015-08-01

Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.

Tunable ultranarrow spectrum selective absorption in a graphene monolayer at terahertz frequency

NASA Astrophysics Data System (ADS)

Wu, Jun

2016-06-01

Complete absorption in a graphene monolayer at terahertz frequency through the critical coupling effect is investigated. It is achieved by sandwiching the graphene monolayer between a dielectric grating and a Bragg grating. The designed graphene absorber exhibits near-unity absorption at resonance but with an ultranarrow spectrum and antenna-like response, which is attributed to the combined effects of guided mode resonance with dielectric grating and the photonic band gap with Bragg grating. In addition to numerical simulation, the electric field distributions are also illustrated to provide a physical understanding of the perfect absorption effect. Furthermore, the absorption performance can be tuned by only changing the Fermi level of graphene, which is beneficial for real application. It is believed that this study may be useful for designing next-generation graphene-based optoelectronic devices.

Ab Initio Modeling of the Electronic Absorption Spectrum of Previtamin D in Solution

NASA Astrophysics Data System (ADS)

Zhu, Tianyang

To study the solvent effects of water on the previtamin D absorption spectrum, we use the quantum mechanics (QM)/molecular mechanics (MM) method combined with replica-exchange molecular dynamics (REMD). The QM method is applied for the previtamin D molecule and the MM method is used for the water molecules. To enhance conformational sampling of the flexible previtamin D molecule we apply REMD. Based on the REMD structures, we calculate the macroscopic ensemble of the absorption spectrum in solution by time-dependent density functional theory (TDDFT). Comparison between the calculated spectrum in the gas phase and in the solution reveals minor influences of the solvent on the absorption spectrum. In the conventional molecule dynamics simulation, the previtamin D molecule can be trapped by local minimum and cannot overcome energetics barriers when it is calculated at the room temperature. In addition, the higher temperature calculation for the molecule in REMD allows to overcome energetics barriers and to change the structure to other rotational isomers, then switch to the lower temperature and gives a more complete result in the configuration space for the lower temperature.

Absorption from iron tablets given with different types of meals.

PubMed

Hallberg, L; Björn-Rasmussen, E; Ekenved, G; Garby, L; Rossander, L; Pleehachinda, R; Suwanik, R; Arvidsson, B

1978-09-01

The absorption of iron from tablets given with 5 types of meals was studied in 153 subjects. The meals were: a hamburger meal with beans and potatoes, a simple breakfast meal, a Latin American meal composed of black beans, rice and maize and two Southeast Asian meals composed of rice, vegetables and spices served with and without fish. The groups were directly compared by relating the absorption from the iron tablets to the absorption from a standardized reference dose of iron given on an empty stomach. The composition of meals with respect to content of meat or fish or the presence of large amounts of phytates seemed to have no influence on the absorption of iron from tablets. The absorption from iron tablets was about 40% higher when they were given with rice meals than when they were given with the other meals studied. The average decrease in absorption by meals was about 50-60% based on a comparison when tablets were given on an empty stomach. When tablets from which the iron was released more slowly were used, the absorption increased by about 30% except when they were given with rice meals, where the absorption was unchanged. The differences among the meals in their effect on the absorption of iron from tablets thus disappeared when the slow-release tablets were given.

Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

PubMed

Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

2016-05-23

The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous measurements of absorption spectrum and refractive index in a microfluidic system.

PubMed

Helseth, Lars Egil

2012-02-13

The characterization of dyes in various solvents requires determination of the absorption spectrum of the dye as well as the refractive index of the solvent. Typically, the refractive index of the solvent and the absorption spectrum of the solute are measured using separate experimental setups where significant liquid volumes are required. In this work the first optical measurement system that is able to do simultaneous measurements of the refractive index of the solvent and the spectral properties of the solute in a microscopic volume is presented. The laser dye Rhodamine 6G in glycerol is investigated, and the refractive index of the solution is monitored using the interference pattern of the light scattered off the channel, while its spectral properties is found by monitoring reflected light from the channel.

The Surprising Absence of Absorption in the Far-ultraviolet Spectrum of Mrk 231

NASA Technical Reports Server (NTRS)

Veilleux, S.; Trippe, M.; Hamann, F.; Rupke, D. S. N.; Tripp, T. M.; Netzer, H.; Lutz, D.; Sembach, K. R.; Krug, H.; Teng, Stacy H.;

A resonant absorption line in the ASCA spectrum of NGC 985?

NASA Astrophysics Data System (ADS)

Nicastro, F.; Fiore, F.; Brandt, N.; Reynolds, C. S.

1999-01-01

We present timing and spectral analyses of the ASCA observation of the Seyfert 1 galaxy NGC 985. The 0.6-10keV spectrum of this source is complex: large residuals are evident below 1keV when fitting the spectrum with a power-law model. Fitting a warm absorber model to the 0.6-2.5keV spectrum gives α=1.12+/-0.04, LogNWAH=21.97+/-0.08 and LogU=0.06+/-0.09, but the residuals continue to show a deficit of counts between 0.9 and 1keV. Adding an absorption line improves the fit, and the energy of the line is consistent with that of Kα NeIX-X resonant absorption lines. Hence, we confirm the presence of an ionized absorber along the line of sight to this source and interpret the further 1keV spectral feature as the first detection of a strong resonant absorption line associated with this system. The extrapolation of this model above 2.5keV produces large positive residuals above 3-4keV. Fitting the data with a broken power law plus warm absorber model gives an acceptable χ2 and Δα~0.5. A narrow iron line at 6.4keV (quasar frame) of equivalent width 138+64-110eV is also present in the ASCA data.

High-resolution discrete absorption spectrum of α-methallyl free radical in the vapor phase

NASA Astrophysics Data System (ADS)

Bayrakçeken, Fuat; Telatar, Ziya; Arı, Fikret; Tunçyürek, Lale; Karaaslan, İpek; Yaman, Ali

2006-09-01

The α-methallyl free radical is formed in the flash photolysis of 3-methylbut-1-ene, and cis-pent-2-ene in the vapor phase, and then subsequent reactions have been investigated by kinetic spectroscopy and gas-liquid chromatography. The photolysis flash was of short duration and it was possible to follow the kinetics of the radicals' decay, which occurred predominantly by bimolecular recombination. The measured rate constant for the α-methallyl recombination was (3.5 ± 0.3) × 10 10 mol -1 l s -1 at 295 ± 2 K. The absolute extinction coefficients of the α-methallyl radical are calculated from the optical densities of the absorption bands. Detailed analysis of related absorption bands and lifetime measurements in the original α-methallyl high-resolution discrete absorption spectrum image were also carried out by image processing techniques.

In vivo and in vitro absorption spectrum of disulphonated aluminum phthalocyanine in tumor-bearing mice

NASA Astrophysics Data System (ADS)

Cubeddu, Rinaldo; Canti, Gianfranco L.; Pifferi, Antonio; Taroni, Paola; Valentini, Gianluca

1995-03-01

The absorption spectrum of disulphonated aluminum phthalocyanine (AlS2Pc) between 650 nm and 695 nm was measured in vivo by means of time-resolved reflectance. The experiments were performed on mice bearing the L1210 leukemia 1, 4, and 7 hr after the i.p. administration of 2.5 mg/kg body weight (b.w.) of AlS2Pc. The absorption peak is centered at 685 nm, red-shifted of 10 - 15 nm with respect to the spectra obtained in solution in various environments. Measurements performed in vitro confirm the results in vivo and seem to suggest that the extracellular environment can cause the shift in the absorption line shape.

H i Absorption in the Steep-Spectrum Superluminal Quasar 3C 216.

PubMed

Pihlström; Vermeulen; Taylor; Conway

1999-11-01

The search for H i absorption in strong compact steep-spectrum sources is a natural way to probe the neutral gas contents in young radio sources. In turn, this may provide information about the evolution of powerful radio sources. The recently improved capabilities of the Westerbork Synthesis Radio Telescope have made it possible to detect a 0.31% (19 mJy) deep neutral atomic hydrogen absorption line associated with the steep-spectrum superluminal quasar 3C 216. The redshift (z=0.67) of the source shifts the frequency of the 21 cm line down to the ultra-high-frequency (UHF) band (850 MHz). The exact location of the H i-absorbing gas remains to be determined by spectral line VLBI observations at 850 MHz. We cannot exclude that the gas might be extended on galactic scales, but we think it is more likely to be located in the central kiloparsec. Constraints from the lack of X-ray absorption probably rule out obscuration of the core region, and we argue that the most plausible site for the H i absorption is in the jet-cloud interaction observed in this source.

Continuous optical measurement system of hemolysis during a photosensitization reaction using absorption spectrum

NASA Astrophysics Data System (ADS)

Hamada, R.; Ogawa, E.; Arai, T.

2018-02-01

To investigate hemolysis phenomena during a photosensitization reaction with the reaction condition continuously and simultaneously for a safety assessment of hemolysis side effect, we constructed an optical system to measure blood sample absorption spectrum during the reaction. Hemolysis degree might be under estimated in general evaluation methods because there is a constant oxygen pressure assumption in spite of oxygen depression take place. By investigating hemoglobin oxidation and oxygen desorption dynamics obtained from the contribution of the visible absorption spectrum and multiple regression analysis, both the hemolysis phenomena and its oxygen environment might be obtained with time. A 664 nm wavelength laser beam for the reaction excitation and 475-650 nm light beam for measuring the absorbance spectrum were arranged perpendicularly crossing. A quartz glass cuvette with 1×10 mm in dimensions for the spectrum measurement was located at this crossing point. A red blood cells suspension medium was arranged with low hematocrit containing 30 μg/ml talaporfin sodium. This medium was irradiated up to 40 J/cm2 . The met-hemoglobin, oxygenatedhemoglobin, and deoxygenated-hemoglobin concentrations were calculated by a multiple regression analysis from the measured spectra. We confirmed the met-hemoglobin concentration increased and oxygen saturation decreased with the irradiation time, which seems to indicate the hemolysis progression and oxygen consumption, respectively. By using our measuring system, the hemolysis progression seems to be obtained with oxygen environment information.

Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes

NASA Astrophysics Data System (ADS)

Blancon, Jean-Christophe; Paillet, Matthieu; Tran, Huy Nam; Than, Xuan Tinh; Guebrou, Samuel Aberra; Ayari, Anthony; Miguel, Alfonso San; Phan, Ngoc-Minh; Zahab, Ahmed-Azmi; Sauvajol, Jean-Louis; Fatti, Natalia Del; Vallée, Fabrice

2013-09-01

The optical properties of single-wall carbon nanotubes are very promising for developing novel opto-electronic components and sensors with applications in many fields. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial. Here we determine using spatial modulation spectroscopy, over a broad optical spectral range, the spectrum and amplitude of the absorption cross-section of individual semiconducting single-wall carbon nanotubes. These quantitative measurements permit determination of the oscillator strength of the different excitonic resonances and their dependencies on the excitonic transition and type of semiconducting nanotube. A non-resonant background is also identified and its cross-section comparable to the ideal graphene optical absorbance. Furthermore, investigation of the same single-wall nanotube either free standing or lying on a substrate shows large broadening of the excitonic resonances with increase of oscillator strength, as well as stark weakening of polarization-dependent antenna effects, due to nanotube-substrate interaction.

Broad-spectrum enhanced absorption of graphene-molybdenum disulfide photovoltaic cells in metal-mirror microcavity.

PubMed

Jiang-Tao, Liu; Yun-Kai, Cao; Hong, Tong; Dai-Qiang, Wang; Zhen-Hua, Wu

2018-04-06

The optical absorption of graphene-molybdenum disulfide photovoltaic cells (GM-PVc) in wedge-shaped metal-mirror microcavities (w-MMCs) combined with a spectrum-splitting structure was studied. Results showed that the combination of spectrum-splitting structure and w-MMC can enable the light absorption of GM-PVcs to reach about 65% in the broad spectrum. The influence of processing errors on the absorption of GM-PVcs in w-MMCs was 3-14 times lower than that of GM-PVcs in wedge photonic crystal microcavities. The light absorption of GM-PVcs reached 60% in the broad spectrum, even with the processing errors. The proposed structure is easy to implement and may have potentially important applications in the development of ultra-thin and high-efficiency solar cells and optoelectronic devices.

Broad-spectrum enhanced absorption of graphene-molybdenum disulfide photovoltaic cells in metal-mirror microcavity

NASA Astrophysics Data System (ADS)

Jiang-Tao, Liu; Yun-Kai, Cao; Hong, Tong; Dai-Qiang, Wang; Zhen-Hua, Wu

2018-04-01

The optical absorption of graphene-molybdenum disulfide photovoltaic cells (GM-PVc) in wedge-shaped metal-mirror microcavities (w-MMCs) combined with a spectrum-splitting structure was studied. Results showed that the combination of spectrum-splitting structure and w-MMC can enable the light absorption of GM-PVcs to reach about 65% in the broad spectrum. The influence of processing errors on the absorption of GM-PVcs in w-MMCs was 3-14 times lower than that of GM-PVcs in wedge photonic crystal microcavities. The light absorption of GM-PVcs reached 60% in the broad spectrum, even with the processing errors. The proposed structure is easy to implement and may have potentially important applications in the development of ultra-thin and high-efficiency solar cells and optoelectronic devices.

Surprises from a Deep ASCA Spectrum of the Broad Absorption Line Quasar PHL 5200

NASA Technical Reports Server (NTRS)

Mathur, Smita; Matt, G.; Green, P. J.; Elvis, M.; Singh, K. P.

2002-01-01

We present a deep (approx. 85 ks) ASCA observation of the prototype broad absorption line quasar (BALQSO) PHL 5200. This is the best X-ray spectrum of a BALQSO yet. We find the following: (1) The source is not intrinsically X-ray weak. (2) The line-of-sight absorption is very strong, with N(sub H) = 5 x 10(exp 23)/sq cm. (3) The absorber does not cover the source completely; the covering fraction is approx. 90%. This is consistent with the large optical polarization observed in this source, implying multiple lines of sight. The most surprising result of this observation is that (4) the spectrum of this BALQSO is not exactly similar to other radio-quiet quasars. The hard X-ray spectrum of PHL 5200 is steep, with the power-law spectral index alpha approx. 1.5. This is similar to the steepest hard X-ray slopes observed so far. At low redshifts, such steep slopes are observed in narrow-line Seyfert 1 (NLS1) galaxies, believed to be accreting at a high Eddington rate. This observation strengthens the analogy between BALQSOs and NLS1 galaxies and supports the hypothesis that BALQSOs represent an early evolutionary state of quasars. It is well accepted that the orientation to the line of sight determines the appearance of a quasar: age seems to play a significant role as well.

NF3: UV Absorption Spectrum Temperature Dependence and the Atmospheric and Climate Forcing Implications

NASA Technical Reports Server (NTRS)

Papadimitriou, Vassileios C.; McGillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

2013-01-01

Nitrogen trifluoride (NF3) is an atmospherically persistent greenhouse gas that is primarily removed by UV photolysis and reaction with O((sup 1)D) atoms. In this work, the NF3 gas-phase UV absorption spectrum, sigma(delta,T), was measured at 16 wavelengths between 184.95 and 250 nm at temperatures between 212 and 296 K. A significant spectrum temperature dependence was observed in the wavelength region most relevant to atmospheric photolysis (200-220 nm) with a decrease in sigma(210 nm,T) of approximately 45 percent between 296 and 212 K. Atmospheric photolysis rates and global annually averaged lifetimes of NF3 were calculated using the Goddard Space Flight Center 2-D model and the sigma(delta,T) parameterization developed in this work. Including the UV absorption spectrum temperature dependence increased the stratospheric photolysis lifetime from 610 to 762 years and the total global lifetime from 484 to 585 years; the NF3 global warming potentials on the 20-, 100-, and 500-year time horizons increased less than 0.3, 1.1, and 6.5 percent to 13,300, 17,700, and 19,700, respectively.

Drug gastrointestinal absorption in rat: Strain and gender differences.

PubMed

Oltra-Noguera, Davinia; Mangas-Sanjuan, Victor; González-Álvarez, Isabel; Colon-Useche, Sarin; González-Álvarez, Marta; Bermejo, Marival

2015-10-12

Predictive animal models of intestinal drug absorption are essential tools in drug development to identify compounds with promising biopharmaceutical properties. In situ perfusion absorption studies are routinely used in the preclinical setting to screen drug candidates. The objective of this work is to explore the differences in magnitude and variability on intestinal absorption associated with rat strain and gender. Metoprolol and Verapamil absorption rate coefficients were determined using the in situ closed loop perfusion model in four strains of rats and in both genders. Strains used were Sprague-Dawley, Wistar-Han, Wistar-Unilever, Long-Evans and CD∗IGS. In the case of Metoprolol only CD∗IGS and Wistar Unilever showed differences between males and females. For Verapamil, Wistar Han and Sprague-Dawley strains do not show differences between male and female rats. That means that in these strains permeability data from male and female could be combined. In male rats, which are commonly used for permeability estimation, there were differences for Metoprolol permeability between Sprague-Dawley (with lower permeability values) and the other strains, while for Verapamil Sprague-Dawley and Wistar-Han showed the lower permeability values. In conclusion, the selection of rat's strain and gender for intestinal absorption experiments is a relevant element during study design and data from different strains may not be always comparable. Copyright © 2015 Elsevier B.V. All rights reserved.

Mg I absorption features in the solar spectrum near 9 and 12 microns

NASA Technical Reports Server (NTRS)

Glenar, David A.; Reuter, Dennis C.; Deming, Drake; Chang, Edward S.

1988-01-01

High-resolution FTS observations from the Kitt Peak National Solar Observatory and the Spacelab 3 ATMOS experiment have revealed additional infrared transitions due to Mg I in the spectra of both quiet sun and sunspot penumbra. In contrast to previous observations, these transitions are seen in absorption, not emission. Absorption intensities range from 1 to 7 percent of the continuum in the quiet sun. In the penumbra, the same features appear to show Zeeman splitting. Modeling of the line profiles in the photospheric spectrum shows evidence for a factor of three overabundance in the n = 5 or more levels of Mg I in the upper photosphere, but with no deviations from a Planck source function. It is concluded that whatever the process that produces the emission (including the Lemke and Holweger mechanism), it must occur well above the tau(5000) = 0.01 level.

Jet-cooled infrared absorption spectrum of the v4 fundamental band of HCOOH and HCOOD

NASA Astrophysics Data System (ADS)

Luo, Wei; Zhang, Yulan; Li, Wenguang; Duan, Chuanxi

2017-04-01

The jet-cooled absorption spectrum of the v4 fundamental band of normal formic acid (HCOOH) and deuterated formic acid (HCOOD) was recorded in the frequency range of 1370-1392 cm-1 with distributed-feedback quantum cascade lasers (DFB-QCLs) as the tunable infrared radiations. A segmented rapid-scan data acquisition scheme was developed for pulsed supersonic jet infrared laser absorption spectroscopy based on DFB-QCLs with a moderate vacuum pumping capacity. The unperturbed band-origin and rotational constants in the excited vibrational state were determined for both HCOOH and HCOOD. The unperturbed band-origin locates at 1379.05447(11) cm-1 for HCOOH, and 1366.48430(39) cm-1 for HCOOD, respectively.

An organoboron compound with a wide absorption spectrum for solar cell applications.

PubMed

Liu, Fangbin; Ding, Zicheng; Liu, Jun; Wang, Lixiang

2017-11-09

Organoboron compounds offer new approaches to tune the electronic structures of π-conjugated molecules. In this work, an electron acceptor (M-BNBP4P-1) is developed by endcapping an organoboron core unit with two strong electron-withdrawing groups. M-BNBP4P-1 exhibits a unique wide absorption spectrum with two strong absorption bands in the long wavelength region (λ max = 771 nm) and the short wavelength region (λ max = 502 nm), which indicate superior sunlight harvesting capability. This is due to its special electronic structure, i.e. a delocalized LUMO and a localized HOMO. Prototype solution-processed organic solar cells based on M-BNBP4P-1 show a power conversion efficiency of 7.06% and a wide photoresponse from 350 nm to 880 nm.

Intermediate Band Material of Titanium-Doped Tin Disulfide for Wide Spectrum Solar Absorption.

PubMed

Hu, Keyan; Wang, Dong; Zhao, Wei; Gu, Yuhao; Bu, Kejun; Pan, Jie; Qin, Peng; Zhang, Xian; Huang, Fuqiang

2018-04-02

Intermediate band (IB) materials are of great significance due to their superior solar absorption properties. Here, two IBs peaking at 0.88 and 1.33 eV are reported to be present in the forbidden gap of semiconducting SnS 2 ( E g = 2.21 eV) by doping titanium up to 6 atom % into the Sn site via a solid-state reaction at 923 K. The solid solution of Sn 1- x Ti x S 2 is able to be formed, which is attributed to the isostructural structure of SnS 2 and TiS 2 . These two IBs were detected in the UV-vis-NIR absorption spectra with the appearance of two additional absorption responses at the respective regions, which in good agreement with the conclusion of first-principles calculations. The valence band maximum (VBM) consists mostly of the S 3p state, and the conduction band minimum (CBM) is the hybrid state composing of Ti 3d (e g ), S 3p, and Sn 5s, and the IBs are mainly the nondegenerate t 2g states of Ti 3d orbitals. The electronic states of Ti 3d reveal a good ability to transfer electrons between metal and S atoms. These wide-spectrum absorption IBs bring about more solar energy utilization to enhance solar thermal collection and photocatalytic degradation of methyl orange.

Absorption of laser plasma in competition with oscillation currents for a terahertz spectrum.

PubMed

Li, Xiaolu; Bai, Ya; Li, Na; Liu, Peng

2018-01-01

We generate terahertz radiation in a supersonic jet of nitrogen molecules pumped by intense two-color laser pulses. The tuning of terahertz spectra from blue shift to red shift is observed by increasing laser power and stagnation pressure, and the red shift range is enlarged with the increased stagnation pressure. Our simulation reveals that the plasma absorption of the oscillation currents and expanded plasma column owing to increased laser intensity and gas number density are crucial factors in the recurrence of the red shift of terahertz spectra. The findings disclose the microscopic mechanism of terahertz radiation and present a controlling knob for the manipulation of a broadband terahertz spectrum from laser plasma.

CFCI3 (CFC-11): UV Absorption Spectrum Temperature Dependence Measurements and the Impact on Atmospheric Lifetime and Uncertainty

NASA Technical Reports Server (NTRS)

Mcgillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

2014-01-01

CFCl3 (CFC-11) is both an atmospheric ozone-depleting and potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95 - 230 nm) and temperature (216 - 296 K). We report a spectrum temperature dependence that is less than currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using a 2-D model and the spectrum parameterization developed in this work. The obtained global annually averaged lifetime was 58.1 +- 0.7 years (2 sigma uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current spectrum recommendations

Frequency-domain method for measuring spectral properties in multiple-scattering media: methemoglobin absorption spectrum in a tissuelike phantom

NASA Astrophysics Data System (ADS)

Fishkin, Joshua B.; So, Peter T. C.; Cerussi, Albert E.; Gratton, Enrico; Fantini, Sergio; Franceschini, Maria Angela

1995-03-01

We have measured the optical absorption and scattering coefficient spectra of a multiple-scattering medium (i.e., a biological tissue-simulating phantom comprising a lipid colloid) containing methemoglobin by using frequency-domain techniques. The methemoglobin absorption spectrum determined in the multiple-scattering medium is in excellent agreement with a corrected methemoglobin absorption spectrum obtained from a steady-state spectrophotometer measurement of the optical density of a minimally scattering medium. The determination of the corrected methemoglobin absorption spectrum takes into account the scattering from impurities in the methemoglobin solution containing no lipid colloid. Frequency-domain techniques allow for the separation of the absorbing from the scattering properties of multiple-scattering media, and these techniques thus provide an absolute

Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT

SciTech Connect

Brabec, Jiri; Lin, Lin; Shao, Meiyue

We present two iterative algorithms for approximating the absorption spectrum of molecules within linear response of time-dependent density functional theory (TDDFT) framework. These methods do not attempt to compute eigenvalues or eigenvectors of the linear response matrix. They are designed to approximate the absorption spectrum as a function directly. They take advantage of the special structure of the linear response matrix. Neither method requires the linear response matrix to be constructed explicitly. They only require a procedure that performs the multiplication of the linear response matrix with a vector. These methods can also be easily modified to efficiently estimate themore » density of states (DOS) of the linear response matrix without computing the eigenvalues of this matrix. We show by computational experiments that the methods proposed in this paper can be much more efficient than methods that are based on the exact diagonalization of the linear response matrix. We show that they can also be more efficient than real-time TDDFT simulations. We compare the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost.« less

Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT

SciTech Connect

Brabec, Jiri; Lin, Lin; Shao, Meiyue

We present a special symmetric Lanczos algorithm and a kernel polynomial method (KPM) for approximating the absorption spectrum of molecules within the linear response time-dependent density functional theory (TDDFT) framework in the product form. In contrast to existing algorithms, the new algorithms are based on reformulating the original non-Hermitian eigenvalue problem as a product eigenvalue problem and the observation that the product eigenvalue problem is self-adjoint with respect to an appropriately chosen inner product. This allows a simple symmetric Lanczos algorithm to be used to compute the desired absorption spectrum. The use of a symmetric Lanczos algorithm only requires halfmore » of the memory compared with the nonsymmetric variant of the Lanczos algorithm. The symmetric Lanczos algorithm is also numerically more stable than the nonsymmetric version. The KPM algorithm is also presented as a low-memory alternative to the Lanczos approach, but the algorithm may require more matrix-vector multiplications in practice. We discuss the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost. Applications to a set of small and medium-sized molecules are also presented.« less

Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT

DOE PAGES

Brabec, Jiri; Lin, Lin; Shao, Meiyue; ...

2015-10-06

We present a special symmetric Lanczos algorithm and a kernel polynomial method (KPM) for approximating the absorption spectrum of molecules within the linear response time-dependent density functional theory (TDDFT) framework in the product form. In contrast to existing algorithms, the new algorithms are based on reformulating the original non-Hermitian eigenvalue problem as a product eigenvalue problem and the observation that the product eigenvalue problem is self-adjoint with respect to an appropriately chosen inner product. This allows a simple symmetric Lanczos algorithm to be used to compute the desired absorption spectrum. The use of a symmetric Lanczos algorithm only requires halfmore » of the memory compared with the nonsymmetric variant of the Lanczos algorithm. The symmetric Lanczos algorithm is also numerically more stable than the nonsymmetric version. The KPM algorithm is also presented as a low-memory alternative to the Lanczos approach, but the algorithm may require more matrix-vector multiplications in practice. We discuss the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost. Applications to a set of small and medium-sized molecules are also presented.« less

Modeling the absorption spectrum of the permanganate ion in vacuum and in aqueous solution

NASA Astrophysics Data System (ADS)

Olsen, Jógvan Magnus Haugaard; Hedegård, Erik Donovan

The absorption spectrum of the MnO$_{4}$$^{-}$ ion has been a test-bed for quantum-chemical methods over the last decades. Its correct description requires highly-correlated multiconfigurational methods, which are incompatible with the inclusion of finite-temperature and solvent effects due to their high computational demands. Therefore, implicit solvent models are usually employed. Here we show that implicit solvent models are not sufficiently accurate to model the solvent shift of MnO$_{4}$$^{-}$, and we analyze the origins of their failure. We obtain the correct solvent shift for MnO$_{4}$$^{-}$ in aqueous solution by employing the polarizable embedding (PE) model combined with a range-separated complete active space short-range density functional theory method (CAS-srDFT). Finite-temperature effects are taken into account by averaging over structures obtained from ab initio molecular dynamics simulations. The explicit treatment of finite-temperature and solvent effects facilitates the interpretation of the bands in the low-energy region of the MnO$_{4}$$^{-}$ absorption spectrum, whose assignment has been elusive.

Paracetamol absorption from different sites in the human small intestine.

PubMed Central

Gramatté, T; Richter, K

1994-01-01

Site-specificity in the small intestinal absorption of paracetamol was investigated using a segmental intestinal steady state perfusion technique (triple-lumen tubing system) combined with simultaneous measurements of serum drug concentrations. Dissolved paracetamol was perfused over 160 min into different parts of the small intestine (65-210 cm beyond the teeth). Each of the four healthy subjects was studied twice with a proximal and a more distal site of perfusion. Serum drug concentrations were similar after proximal and distal perfusions. Mean drug absorption rates calculated from intestinal aspirate concentrations were similar in both parts of the intestine--proximal: 869 micrograms 30 cm-1 min-1 (95% CI: 659-1079) vs distal: 941 micrograms 30 cm-1 min-1 (794-1088). The absorption rate was related directly to the amount of paracetamol perfused per unit time as well as to the rate of transmucosal water fluxes. PMID:7917782

Infrared absorption spectrum of the simplest deuterated Criegee intermediate CD{sub 2}OO

SciTech Connect

Huang, Yu-Hsuan; Nishimura, Yoshifumi; Witek, Henryk A., E-mail: hwitek@mail.nctu.edu.tw, E-mail: yplee@mail.nctu.edu.tw

We report a transient infrared (IR) absorption spectrum of the simplest deuterated Criegee intermediate CD{sub 2}OO recorded using a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. CD{sub 2}OO was produced from photolysis of flowing mixtures of CD{sub 2}I{sub 2}, N{sub 2}, and O{sub 2} (13 or 87 Torr) with laser light at 308 nm. The recorded spectrum shows close structural similarity with the spectrum of CH{sub 2}OO reported previously [Y.-T. Su et al., Science 340, 174 (2013)]. The four bands observed at 852, 1017, 1054, and 1318 cm{sup −1} are assigned to the OO stretching mode, two distinctmore » in-plane OCD bending modes, and the CO stretching mode of CD{sub 2}OO, respectively, according to vibrational wavenumbers, IR intensities, rotational contours, and deuterium-isotopic shifts predicted with extensive quantum-chemical calculations. The CO-stretching mode of CD{sub 2}OO at 1318 cm{sup −1} is blue shifted from the corresponding band of CH{sub 2}OO at 1286 cm{sup −1}; this can be explained by a mechanism based on mode mixing and isotope substitution. A band near 936 cm{sup −1}, observed only at higher pressure (87 Torr), is tentatively assigned to the CD{sub 2} wagging mode of CD{sub 2}IOO.« less

Chemical and spectral behavior of nitric acid in aqueous sulfuric acid solutions: Absorption spectrum and molar absorption coefficient of nitronium ion

NASA Astrophysics Data System (ADS)

Ershov, Boris G.; Panich, Nadezhda M.

2018-01-01

The chemical species formed from nitric acid in aqueous solutions of sulfuric acid (up to 18.0 mol L- 1) were studied by optical spectroscopy method. The concentration region of nitronium ion formation was identified and NO2+ ion absorption spectrum was measured (λmax ≤ 190 nm and ε190 = 1040 ± 50 mol- 1 L cm- 1).

Substituent and solvent effects on the UV-vis absorption spectrum of the photoactive yellow protein chromophore.

PubMed

García-Prieto, F Fernández; Aguilar, M A; Galván, I Fdez; Muñoz-Losa, A; Olivares del Valle, F J; Sánchez, M L; Martín, M E

2015-05-28

Solvent effects on the UV-vis absorption spectra and molecular properties of four models of the photoactive yellow protein (PYP) chromophore have been studied with ASEP/MD, a sequential quantum mechanics/molecular mechanics method. The anionic trans-p-coumaric acid (pCA(-)), thioacid (pCTA(-)), methyl ester (pCMe(-)), and methyl thioester (pCTMe(-)) derivatives have been studied in gas phase and in water solution. We analyze the modifications introduced by the substitution of sulfur by oxygen atoms and hydrogen by methyl in the coumaryl tail. We have found some differences in the absorption spectra of oxy and thio derivatives that could shed light on the different photoisomerization paths followed by these compounds. In solution, the spectrum substantially changes with respect to that obtained in the gas phase. The n → π1* state is destabilized by a polar solvent like water, and it becomes the third excited state in solution displaying an important blue shift. Now, the π → π1* and π → π2* states mix, and we find contributions from both transitions in S1 and S2. The presence of the sulfur atom modulates the solvent effect and the first two excited states become practically degenerate for pCA(-) and pCMe(-) but moderately well-separated for pCTA(-) and pCTMe(-).

Interactions of praseodymium and neodymium with nucleosides and nucleotides: absorption difference and comparative absorption spectral study.

PubMed

Misra, S N; Anjaiah, K; Joseph, G; Abdi, S H

1992-02-01

The interactions of praseodymium(III) and neodymium(III) with nucleosides and nucleotides have been studied in different stoichiometry in water and water-DMF mixtures by employing absorption difference and comparative absorption spectrophotometry. The 4f-4f bands were analysed by linear curve analysis followed by gaussian curve analysis, and various spectral parameters were computed, using partial and multiple regression method. The magnitude of changes in both energy interaction and intensity were used to explore the degree of outer and inner sphere coordination, incidence of covalency and the extent of metal 4f-orbital involvement in chemical bonding. Crystalline complexes of the type [Ln(nucleotide)2(H2O)2]- (where nucleotide--GMP or IMP) were characterized by IR, 1H NMR, 31P NMR data. These studies indicated that the binding of the nucleotide is through phosphate oxygen in a bidentate manner and the complexes undergo substantial ionisation in aqueous medium, thereby supporting the observed weak 4f-4f bands and lower values for nephelauxetic effect (1-beta), bonding (b) and covalency (delta) parameters derived from coulombic and spin orbit interaction parameters.

The integrated radio continuum spectrum of M33 - Evidence for free-free absorption by cool ionized gas

NASA Technical Reports Server (NTRS)

Israel, F. P.; Mahoney, M. J.; Howarth, N.

1992-01-01

We present measurements of the integrated radio continuum flux density of M33 at frequencies between 22 and 610 MHz and discuss the radio continuum spectrum of M33 between 22 MHz and 10 GHz. This spectrum has a turnover between 500 and 900 MHz, depending on the steepness of the high frequency radio spectrum of M33. Below 500 MHz the spectrum is relatively flat. We discuss possible mechanisms to explain this spectral shape and consider efficient free-free absorption of nonthermal emission by a cool (not greater than 1000 K) ionized gas to be a very likely possibility. The surface filling factor of both the nonthermal and the thermal material appears to be small (of order 0.001), which could be explained by magnetic field/density fluctuations in the M 33 interstellar medium. We briefly speculate on the possible presence of a nuclear radio source with a steep spectrum.

Signs of strong Na and K absorption in the transmission spectrum of WASP-103b

NASA Astrophysics Data System (ADS)

Lendl, M.; Cubillos, P. E.; Hagelberg, J.; Müller, A.; Juvan, I.; Fossati, L.

2017-09-01

Context. Transmission spectroscopy has become a prominent tool for characterizing the atmospheric properties on close-in transiting planets. Recent observations have revealed a remarkable diversity in exoplanet spectra, which show absorption signatures of Na, K and H2O, in some cases partially or fully attenuated by atmospheric aerosols. Aerosols (clouds and hazes) themselves have been detected in the transmission spectra of several planets thanks to wavelength-dependent slopes caused by the particles' scattering properties. Aims: We present an optical 550-960 nm transmission spectrum of the extremely irradiated hot Jupiter WASP-103b, one of the hottest (2500 K) and most massive (1.5 MJ) planets yet to be studied with this technique. WASP-103b orbits its star at a separation of less than 1.2 times the Roche limit and is predicted to be strongly tidally distorted. Methods: We have used Gemini/GMOS to obtain multi-object spectroscopy throughout three transits of WASP-103b. We used relative spectrophotometry and bin sizes between 20 and 2 nm to infer the planet's transmission spectrum. Results: We find that WASP-103b shows increased absorption in the cores of the alkali (Na, K) line features. We do not confirm the presence of any strong scattering slope as previously suggested, pointing towards a clear atmosphere for the highly irradiated, massive exoplanet WASP-103b. We constrain the upper boundary of any potential cloud deck to reside at pressure levels above 0.01 bar. This finding is in line with previous studies on cloud occurrence on exoplanets which find that clouds dominate the transmission spectra of cool, low surface gravity planets while hot, high surface gravity planets are either cloud-free, or possess clouds located below the altitudes probed by transmission spectra. The spectrophotometric time series data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc

The Hubble Space Telescope Quasar Absorption Line Key Project: The Unusual Absorption-Line System in the Spectrum of PG 2302+029--Ejected or Intervening?

NASA Technical Reports Server (NTRS)

Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent, W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron, J.; Boksenberg, A.; Savage, B. D.;

The Clinician Perspective on Sex Differences in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Jamison, Rene; Bishop, Somer L.; Huerta, Marisela; Halladay, Alycia K.

2017-01-01

Research studies using existing samples of individuals with autism spectrum disorders have identified differences in symptoms between males and females. Differences are typically reported in school age and adolescence, with similarities in symptom presentation at earlier ages. However, existing studies on sex differences are significantly limited,…

The Mandarin Childhood Autism Spectrum Test (CAST): Sex Differences

ERIC Educational Resources Information Center

Sun, Xiang; Allison, Carrie; Auyeung, Bonnie; Matthews, Fiona E.; Sharp, Stephen J.; Baron-Cohen, Simon; Brayne, Carol

2014-01-01

Sex differences in social and communication behaviours related to autism spectrum conditions (ASC) have been investigated mainly in Western populations. Little research has been done in Chinese populations. This study explored sex differences related to ASC characteristics by examining differences in item responses and score distributions in…

Absorption spectrum and ultrafast response of monolayer and bilayer transition-metal dichalcogenides

NASA Astrophysics Data System (ADS)

Turkowski, Volodymyr; Ramirez-Torres, Alfredo; Rahman, Talat S.

2015-03-01

We apply a combined time-dependent density functional theory and many-body theory approach to examine the absorption spectrum and nonequilibrium response of monolayer and bilayer MoS2, MoSe2, WS2 and WSe2 systems. In particular, we evaluate the possibility of existence of bound states - excitons and trions in the undoped systems. In a previous work we have already demonstrated that the binding energies of these states in the monolayer systems are large which makes them available for room temperature applications. We analyze the possibility of ultrafast electron-hole separation in bilayer systems through inter-layer hole transfer, and show that such a possibility exists, in agreement with experimental observations. For doped systems we consider the possibility of Mahan excitonic states in monolayers and show that the binding energy for these states is of the order of 10 meV. We perform a detailed analysis of the relaxation of doped monolayers excited by ultrafast laser pulse by taking into account electron-phonon scattering effects, and demonstrate that ultrafast (10-100fs) processes, including luminescence, may be relevant for these materials. Work supported in part by DOE Grant No. DOE-DE-FG02-07ER46354.

Herbicidal Spectrum, Absorption and Transportation, and Physiological Effect on Bidens pilosa of the Natural Alkaloid Berberine.

PubMed

Wu, Jiao; Ma, Jing-Jing; Liu, Bo; Huang, Lun; Sang, Xiao-Qing; Zhou, Li-Juan

2017-08-02

Berberine is a natural herbicidal alkaloid from Coptis chinensis Franch. Here we characterized its herbicidal spectrum and absorption and transportation in the plant, along with the possible mechanism. Berberine showed no effect on the germination of the 10 tested plants. The IC 50 values of berberine on the primary root length and fresh weight of the 10 tested plants ranged from 2.91 to 9.79 mg L -1 and 5.76 to 35.07 mg L -1 , respectively. Berberine showed a similar herbicidal effect on Bidens pilosa as the commercial naturally derived herbicide cinmethylin. HPLC and fluorescence analysis revealed that berberine was mainly absorbed by B. pilosa root and transported through vascular bundle acropetally. Enzyme activity studies, GC-MS analysis, and SEM and TEM observations indicated that berberine might first function on the cell membrane indicated by variation of the IUFA percent and then cause POD, PPO, and SOD activity changes and cellular structure deformity, which was eventually expressed as the decrease of cell adaptation ability and abnormal cell function and may even result in cell death. Environmental safety evaluation tests revealed that berberine was low in toxicity to Brachydanio rerio. These indicate that berberine has the potential to be a bioherbicide and/or a lead molecule for new herbicides.

The identification of hydrophobic sites on the surface of proteins using absorption difference spectroscopy of bromophenol blue.

PubMed

Bertsch, M; Mayburd, A L; Kassner, R J

2003-02-15

Hydrophobic sites on the surface of protein molecules are thought to have important functional roles. The identification of such sites can provide information about the function and mode of interaction with other cellular components. While the fluorescence enhancement of polarity-sensitive dyes has been useful in identifying hydrophobic sites on a number of targets, strong intrinsic quenching of Nile red and ANSA dye fluorescence is observed on binding to a cytochrome c('). Fluorescence quenching is also observed to take place in the presence of a variety of other biologically important molecules which can compromise the quantitative determination of binding constants. Absorption difference spectroscopy is shown not to be sensitive to the presence of fluorescence quenchers but sensitive enough to measure binding constants. The dye BPB is shown to bind to the same hydrophobic sites on proteins as polarity-sensitive fluorescence probes. The absorption spectrum of BPB is also observed to be polarity sensitive. A binding constant of 3x10(6)M(-1) for BPB to BSA has been measured by absorption difference spectroscopy. An empirical correlation is observed between the shape of the absorption difference spectrum of BPB and the polarity of the environment. The results indicate that absorption difference spectroscopy of BPB provides a valuable supplement to fluorescence for determining the presence of hydrophobic sites on the surface of proteins as well as a method for measuring binding constants.

The clinician perspective on sex differences in autism spectrum disorders.

PubMed

Jamison, Rene; Bishop, Somer L; Huerta, Marisela; Halladay, Alycia K

2017-08-01

Research studies using existing samples of individuals with autism spectrum disorders have identified differences in symptoms between males and females. Differences are typically reported in school age and adolescence, with similarities in symptom presentation at earlier ages. However, existing studies on sex differences are significantly limited, making it challenging to discern if, how, and at what point in development females with autism spectrum disorder actually exhibit a different behavioral presentation than males. The purpose of this study was to gather impressions from a large group of clinicians to isolate specific areas for future study of sex differences. Clinicians were surveyed about their opinions and perceptions of symptom severity in females, as compared to males, at different points during development. They were also asked to provide open-ended responses about female symptom presentation. Consistent with previous literature, clinicians noted more sex-related differences in restricted and repetitive behaviors and fewer differences for social communication features. Differences were most commonly observed in school age and adolescence, suggesting this time period as a critical and particularly vulnerable window for females with autism spectrum disorder. The results are discussed in the context of other male/female differences across development so that more targeted investigations of autism spectrum disorder sex differences across development.

Determining photon energy absorption parameters for different soil samples

PubMed Central

Kucuk, Nil; Tumsavas, Zeynal; Cakir, Merve

2013-01-01

The mass attenuation coefficients (μs) for five different soil samples were measured at 661.6, 1173.2 and 1332.5 keV photon energies. The soil samples were separately irradiated with 137Cs and 60Co (370 kBq) radioactive point gamma sources. The measurements were made by performing transmission experiments with a 2″ × 2″ NaI(Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of 137Cs. The effective atomic numbers (Zeff) and the effective electron densities (Neff) were determined experimentally and theoretically using the obtained μs values for the soil samples. Furthermore, the Zeff and Neff values of the soil samples were computed for the total photon interaction cross-sections using theoretical data over a wide energy region ranging from 1 keV to 15 MeV. The experimental values of the soils were found to be in good agreement with the theoretical values. Sandy loam and sandy clay loam soils demonstrated poor photon energy absorption characteristics. However, clay loam and clay soils had good photon energy absorption characteristics. PMID:23179375

Gender Differences in Symptoms of Autism Spectrum Disorders in Toddlers

ERIC Educational Resources Information Center

Sipes, Megan; Matson, Johnny L.; Worley, Julie A.; Kozlowski, Alison M.

2011-01-01

Gender differences in symptoms representing the triad of impairments of Autism Spectrum Disorders remain unclear. To date, the majority of research conducted on this topic has utilized samples of older children. Thus, the purpose of the current study was to utilize a sample of toddlers to investigate gender differences in symptom endorsements of…

Sex Differences in Toddlers with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Carter, Alice S.; Black, David O.; Tewani, Sonia; Connolly, Christine E.; Kadlec, Mary Beth; Tager-Flusberg, Helen

2007-01-01

Although autism spectrum disorders (ASD) prevalence is higher in males than females, few studies address sex differences in developmental functioning or clinical manifestations. Participants in this study of sex differences in developmental profiles and clinical symptoms were 22 girls and 68 boys with ASD (mean age = 28 months). All children…

Spectrum of excess partial molar absorptivity. Part II: a near infrared spectroscopic study of aqueous Na-halides.

PubMed

Sebe, Fumie; Nishikawa, Keiko; Koga, Yoshikata

2012-04-07

Our earlier thermodynamic studies suggested that F(-) and Cl(-) form hydration shells with the hydration number 14 ± 2 and 2.3 ± 0.6, respectively, and leave the bulk H(2)O away from hydration shells unperturbed. Br(-) and I(-), on the other hand, form hydrogen bonds directly with the momentarily existing hydrogen bond network of H(2)O, and retard the degree of entropy-volume cross fluctuation inherent in liquid H(2)O. The effect of the latter is stronger for I(-) than Br(-). Here we seek additional information about this qualitative difference between Cl(-) and (Br(-) and I(-)) pair by near infrared (NIR) spectroscopy. We analyze the ν(2) + ν(3) band of H(2)O in the range 4600-5500 cm(-1) of aqueous solutions of NaCl, NaBr and NaI, by a new approach. From observed absorbance, we calculate excess molar absorptivity, ε(E), excess over the additive contributions of solute and solvent. ε(E) thus contains information about the effect of inter-molecular interactions in the ν(2) + ν(3) spectrum. The spectrum of ε(E) shows three bands; two negative ones at 5263 and 4873 cm(-1), and the positive band at 5123 cm(-1). We then define and calculate the excess partial molar absorptivity of each salt, ε(E)(salt). From the behaviour of ε(E)(salt) we suggest that the negative band at 5263 cm(-1) represents free H(2)O without much hydrogen bonding under the influence of local electric field of ions. Furthermore, from a sudden change in the x(salt) (mole fraction of salt) dependence of ε(E)(salt), we suggest that there is an ion-pairing in x(salt) > 0.032, 0.036, and 0.04 for NaCl, NaBr and NaI respectively. The positive band of ε(E) at 5123 cm(-1) is attributed to a modestly organized hydrogen bond network of H(2)O (or liquid-likeness), and the x(salt) dependence of ε indicated a qualitative difference in the effect of Cl(-) from those of Br(-) and I(-). Namely, the values of ε(E)(salt) stay constant for Cl(-) but those for Br(-) and I(-) decrease smoothly on

An absorption profile centred at 78 megahertz in the sky-averaged spectrum

NASA Astrophysics Data System (ADS)

Bowman, Judd D.; Rogers, Alan E. E.; Monsalve, Raul A.; Mozdzen, Thomas J.; Mahesh, Nivedita

2018-03-01

After stars formed in the early Universe, their ultraviolet light is expected, eventually, to have penetrated the primordial hydrogen gas and altered the excitation state of its 21-centimetre hyperfine line. This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz. Here we report the detection of a flattened absorption profile in the sky-averaged radio spectrum, which is centred at a frequency of 78 megahertz and has a best-fitting full-width at half-maximum of 19 megahertz and an amplitude of 0.5 kelvin. The profile is largely consistent with expectations for the 21-centimetre signal induced by early stars; however, the best-fitting amplitude of the profile is more than a factor of two greater than the largest predictions. This discrepancy suggests that either the primordial gas was much colder than expected or the background radiation temperature was hotter than expected. Astrophysical phenomena (such as radiation from stars and stellar remnants) are unlikely to account for this discrepancy; of the proposed extensions to the standard model of cosmology and particle physics, only cooling of the gas as a result of interactions between dark matter and baryons seems to explain the observed amplitude. The low-frequency edge of the observed profile indicates that stars existed and had produced a background of Lyman-α photons by 180 million years after the Big Bang. The high-frequency edge indicates that the gas was heated to above the radiation temperature less than 100 million years later.

An absorption profile centred at 78 megahertz in the sky-averaged spectrum.

PubMed

Bowman, Judd D; Rogers, Alan E E; Monsalve, Raul A; Mozdzen, Thomas J; Mahesh, Nivedita

2018-02-28

After stars formed in the early Universe, their ultraviolet light is expected, eventually, to have penetrated the primordial hydrogen gas and altered the excitation state of its 21-centimetre hyperfine line. This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz. Here we report the detection of a flattened absorption profile in the sky-averaged radio spectrum, which is centred at a frequency of 78 megahertz and has a best-fitting full-width at half-maximum of 19 megahertz and an amplitude of 0.5 kelvin. The profile is largely consistent with expectations for the 21-centimetre signal induced by early stars; however, the best-fitting amplitude of the profile is more than a factor of two greater than the largest predictions. This discrepancy suggests that either the primordial gas was much colder than expected or the background radiation temperature was hotter than expected. Astrophysical phenomena (such as radiation from stars and stellar remnants) are unlikely to account for this discrepancy; of the proposed extensions to the standard model of cosmology and particle physics, only cooling of the gas as a result of interactions between dark matter and baryons seems to explain the observed amplitude. The low-frequency edge of the observed profile indicates that stars existed and had produced a background of Lyman-α photons by 180 million years after the Big Bang. The high-frequency edge indicates that the gas was heated to above the radiation temperature less than 100 million years later.

PARTIAL REVISION: ABSORPTION SPECTRUM AND QUANTUM STATES OF THE PRASEODYMIUM ION. I. SINGLE CRYSTALS OF PRASEODYMIUM CHLORIDE

SciTech Connect

Sayre, E.V.; Sancier, K.M.; Freed, S.

1958-07-01

In an analysis of term splitting in the absorption spectrum of 24 samples of praseodymium chloride, Judd (Proc. Roy. Soc. (London) A241, 414(1957)) found all but two of the authors' results to be constant with his. A discussion of reconciliation is presentrd, and the authors point out that the error is due to a mistake in descrimination between electronic transitions and the weak vibrationally coupled lines. (J.R.D.)

Sex Differences in Arab Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Amr, Mostafa; Raddad, Dahoud; El-Mehesh, Fatima; Mahmoud, El-Hassanin; El-Gilany, Abdel-Hady

2011-01-01

Although autism spectrum disorders (ASD) prevalence is higher in males than females in Arab countries, few studies address sex differences in autistic symptoms and coexiting behavioral problems. A total of 37 boys and 23 girls recruited from three Arab countries (Egypt, Saudi Arabia, Jordan) matched for age and IQ. They were compared using Indian…

The origin of blueshifted absorption features in the X-ray spectrum of PG 1211+143: outflow or disc

NASA Astrophysics Data System (ADS)

Gallo, L. C.; Fabian, A. C.

2013-07-01

In some radio-quiet active galactic nuclei (AGN), high-energy absorption features in the X-ray spectra have been interpreted as ultrafast outflows (UFOs) - highly ionized material (e.g. Fe XXV and Fe XXVI) ejected at mildly relativistic velocities. In some cases, these outflows can carry energy in excess of the binding energy of the host galaxy. Needless to say, these features demand our attention as they are strong signatures of AGN feedback and will influence galaxy evolution. For the same reason, alternative models need to be discussed and refuted or confirmed. Gallo and Fabian proposed that some of these features could arise from resonance absorption of the reflected spectrum in a layer of ionized material located above and corotating with the accretion disc. Therefore, the absorbing medium would be subjected to similar blurring effects as seen in the disc. A priori, the existence of such plasma above the disc is as plausible as a fast wind. In this work, we highlight the ambiguity by demonstrating that the absorption model can describe the ˜7.6 keV absorption feature (and possibly other features) in the quasar PG 1211+143, an AGN that is often described as a classic example of a UFO. In this model, the 2-10 keV spectrum would be largely reflection dominated (as opposed to power law dominated in the wind models) and the resonance absorption would be originating in a layer between about 6 and 60 gravitational radii. The studies of such features constitute a cornerstone for future X-ray observatories like Astro-H and Athena+. Should our model prove correct, or at least important in some cases, then absorption will provide another diagnostic tool with which to probe the inner accretion flow with future missions.

A laboratory study of the UV Absorption Spectrum of the ClO Dimer (Cl2O2) and the Implications for Polar Stratospheric Ozone Depletion

NASA Astrophysics Data System (ADS)

Papanastasiou, D. K.; Papadimitriou, V. C.; Fahey, D. W.; Burkholder, J. B.

2009-12-01

Chlorine containing species play an important role in catalytic ozone depleting cycles in the Antarctic and Arctic stratosphere. The ClO dimer (Cl2O2) catalytic ozone destruction cycle accounts for the majority of the observed polar ozone loss. A key step in this catalytic cycle is the UV photolysis of Cl2O2. The determination of the Cl2O2 UV absorption spectrum has been the subject of several studies since the late 1980’s. Recently, Pope et al. (J. Phys. Chem. A, 111, 4322, 2007) reported significantly lower absorption cross sections for Cl2O2 for the atmospherically relevant wavelength region, >300 nm, than currently recommended for use in atmospheric models. If correct, the Pope et al. results would alter our understanding of the chemistry of polar ozone depletion significantly. In this study, the UV absorption spectrum and absolute cross sections of gas-phase Cl2O2 are reported for the wavelength range 200 - 420 nm at ~200 K. Sequential pulsed laser photolysis of various precursors were used to produce the ClO radical and Cl2O2 via the subsequent ClO + ClO + M reaction under static conditions. UV absorption spectra of the reaction mixture were measured using a diode array spectrometer after completion of the gas-phase radical chemistry. The spectral analysis utilized the observed isosbestic points, reaction stoichiometry, and chlorine mass balance to determine the UV spectrum and absolute cross section of Cl2O2. A complementary experimental technique similar to that used by Pope et al. was also used in this study. We obtained consistent Cl2O2 UV absorption spectra using the two different techniques. The Cl2O2 absorption cross sections for wavelengths in the 300 - 420 nm range were found to be in very good agreement with the values reported previously by Burkholder et al. (J. Phys. Chem. A, 94, 687, 1990) and significantly greater than the Pope et al. values in this atmospherically important wavelength region. A possible explanation for the disagreement with

Nuclear quantum effects in electronically adiabatic quantum time correlation functions: Application to the absorption spectrum of a hydrated electron

NASA Astrophysics Data System (ADS)

Turi, László; Hantal, György; Rossky, Peter J.; Borgis, Daniel

2009-07-01

A general formalism for introducing nuclear quantum effects in the expression of the quantum time correlation function of an operator in a multilevel electronic system is presented in the adiabatic limit. The final formula includes the nuclear quantum time correlation functions of the operator matrix elements, of the energy gap, and their cross terms. These quantities can be inferred and evaluated from their classical analogs obtained by mixed quantum-classical molecular dynamics simulations. The formalism is applied to the absorption spectrum of a hydrated electron, expressed in terms of the time correlation function of the dipole operator in the ground electronic state. We find that both static and dynamic nuclear quantum effects distinctly influence the shape of the absorption spectrum, especially its high energy tail related to transitions to delocalized electron states. Their inclusion does improve significantly the agreement between theory and experiment for both the low and high frequency edges of the spectrum. It does not appear sufficient, however, to resolve persistent deviations in the slow Lorentzian-like decay part of the spectrum in the intermediate 2-3 eV region.

The gas-phase absorption spectrum of a neutral GFP model chromophore.

PubMed

Lammich, L; Petersen, M Axman; Nielsen, M Brøndsted; Andersen, L H

2007-01-01

We have studied the gas-phase absorption properties of the green fluorescent protein (GFP) chromophore in its neutral (protonated) charge state in a heavy-ion storage ring. To accomplish this we synthesized a new molecular chromophore with a charged NH(3) group attached to a neutral model chromophore of GFP. The gas-phase absorption cross section of this chromophore molecule as a function of the wavelength is compared to the well-known absorption profile of GFP. The chromophore has a maximum absorption at 415 +/- 5 nm. When corrected for the presence of the charged group attached to the GFP model chromophore, the unperturbed neutral chromophore is predicted to have an absorption maximum at 399 nm in vacuum. This is very close to the corresponding absorption peak of the protein at 397 nm. Together with previous data obtained with an anionic GFP model chromophore, the present data show that the absorption of GFP is primarily determined by intrinsic chromophore properties. In other words, there is strong experimental evidence that, in terms of absorption, the conditions in the hydrophobic interior of this protein are very close to those in vacuum.

Gender differences in first onset Schizophrenia spectrum psychoses.

PubMed

Talonen, Sanni; Väänänen, Juha; Kaltiala-Heino, Riittakerttu

2017-02-01

Mental health profiles differ between boys and girls from puberty onwards. It is not known whether differences also extend to symptom presentation in schizophrenia spectrum disorders. It may be that girls and boys are not treated entirely equally by the professionals. To study gender differences in symptom profiles, family adversities, pathway to care, and characteristics of inpatient treatment at the first episode of diagnosed schizophrenia spectrum disorder (F20-29) among adolescents aged 13-17. A retrospective chart review of all (n = 106) consecutive adolescents diagnosed for the first time with schizophrenia spectrum disorder (F20-29) in a specified catchment area. Girls and boys were compared with regard to sociodemographics, pathways to care, living arrangements, symptom profiles, and treatment received. During the study period more adolescent girls (n = 70, 66%) than boys (n = 36, 34%) were diagnosed with schizophrenia spectrum (F20-29) psychoses, most commonly F29. Girls were moreover younger (mean age = 15.46) than boys (mean age = 16.62) at admission. Girls more often displayed mood symptoms and boys aggressive behaviours, alcohol abuse problems, and isolation. Family adversities recorded as current stressors were more numerous among girls. Girls were more likely to be referred to specialized after-care than boys. The gender differences observed in symptoms presentation are reminiscent of differences encountered in the general adolescent population. Prior to transition to psychosis, girls and boys are equally in contact with psychiatric services due to other (possibly prodromal) symptoms/disorders. Family adversities may be more stressful for girls vulnerable to psychosis than to boys.

Purification of electron-transferring flavoprotein from Megasphaera elsdenii and binding of additional FAD with an unusual absorption spectrum.

PubMed

Sato, Kyosuke; Nishina, Yasuzo; Shiga, Kiyoshi

2003-11-01

Electron-transferring flavoprotein (ETF), its redox partner flavoproteins, i.e., D-lactate dehydrogenase and butyryl-CoA dehydrogenase, and another well-known flavoprotein, flavodoxin, were purified from the same starting cell paste of an anaerobic bacterium, Megasphaera elsdenii. The purified ETF contained one mol FAD/mol ETF as the sole non-protein component and bound almost one mol of additional FAD. This preparation is a better subject for investigations of M. elsdenii ETF than the previously isolated ETF, which contains varying amounts of FAD and varying percentages of modified flavins such as 6-OH-FAD and 8-OH-FAD. The additionally bound FAD shows an anomalous absorption spectrum with strong absorption around 400 nm. This spectral change is not due to a chemical modification of the flavin ring because the flavin released by KBr or guanidine hydrochloride is normal FAD. It is also not due to unknown small molecules because the same spectrum appears when ETF is reconstituted from its guanidine-denatured subunits and FAD. A similar anomalous spectrum was observed for AMP-free pig ETF under acidic conditions, suggesting a common flavin environment between pig and M. elsdenii ETFs.

Experimental and Ab Initio Studies of the HDO Absorption Spectrum in the 13165-13500 1/cm Spectral Region

NASA Technical Reports Server (NTRS)

Schwenke, David; Naumenko, Olga; Bertseva, Elena; Campargue, Alain; Arnold, James O. (Technical Monitor)

2000-01-01

The HDO absorption spectrum has been recorded in the 13165 - 13500 cm(exp-1) spectral region by Intracavity Laser Absorption Spectroscopy. The spectrum (615 lines), dominated by the 2n2 + 3n3 and n1+3n3 bands was assigned and modeled leading to the derivation of 196 accurate energy levels of the (103) and (023) vibrational states. Finally, 150 of these levels have been reproduced by an effective Hamiltonian involving two vibrational dark states interacting with the (023) and ( 103) bright states. The rms deviation achieved by variation of 28 parameters is 0.05-1 cm, compared to an averaged experimental uncertainty of 0.007-1 cm, indicating the limit of validity of the effective Hamiltonian approach for HDO at high vibrational excitation. The predictions of previous ab initio calculations of the HDO spectrum were extensively used in the assignment process. The particular spectral region under consideration has been used to test and discuss the improvements of new ab initio calculations recently performed on the basis of the same potential energy surface but with an improved dipole moment surface. The improvements concern both the energy levels and the line intensities. In particular, the strong hybrid character of the n1+3n3 band is very well accounted for by the the new ab initio calculations.

Quantum Monte Carlo for the x-ray absorption spectrum of pyrrole at the nitrogen K-edge

SciTech Connect

Zubarev, Dmitry Yu.; Austin, Brian M.; Lester, William A. Jr.

Fixed-node diffusion Monte Carlo (FNDMC) is used to simulate the x-ray absorption spectrum of a gas-phase pyrrole molecule at the nitrogen K-edge. Trial wave functions for core-excited states are constructed from ground-state Kohn-Sham determinants substituted with singly occupied natural orbitals from configuration interaction with single excitations calculations of the five lowest valence-excited triplet states. The FNDMC ionization potential (IP) is found to lie within 0.3 eV of the experimental value of 406.1 {+-} 0.1 eV. The transition energies to anti-bonding virtual orbitals match the experimental spectrum after alignment of IP values and agree with the existing assignments.

UV absorption spectrum of the ClO dimer (Cl2O2) between 200 and 420 nm.

PubMed

Papanastasiou, Dimitrios K; Papadimitriou, Vassileios C; Fahey, David W; Burkholder, James B

2009-12-10

The UV photolysis of Cl(2)O(2) (dichlorine peroxide) is a key step in the catalytic destruction of polar stratospheric ozone. In this study, the gas-phase UV absorption spectrum of Cl(2)O(2) was measured using diode array spectroscopy and absolute cross sections, sigma, are reported for the wavelength range 200-420 nm. Pulsed laser photolysis of Cl(2)O at 248 nm or Cl(2)/Cl(2)O mixtures at 351 nm at low temperature (200-228 K) and high pressure (approximately 700 Torr, He) was used to produce ClO radicals and subsequently Cl(2)O(2) via the termolecular ClO self-reaction. The Cl(2)O(2) spectrum was obtained from spectra recorded following the completion of the gas-phase ClO radical chemistry. The spectral analysis used observed isosbestic points at 271, 312.9, and 408.5 nm combined with reaction stoichiometry and chlorine mass balance to determine the Cl(2)O(2) spectrum. The Cl(2)O(2) UV absorption spectrum peaks at 244.5 nm with a cross section of 7.6(-0.5)(+0.8) x 10(-18) cm(2) molecule(-1) where the quoted error limits are 2sigma and include estimated systematic errors. The Cl(2)O(2) absorption cross sections obtained for wavelengths in the range 300-420 nm are in good agreement with the Cl(2)O(2) spectrum reported previously by Burkholder et al. (J. Phys. Chem. A 1990, 94, 687) and significantly higher than the values reported by Pope et al. (J. Phys. Chem. A 2007, 111, 4322). A possible explanation for the discrepancy in the Cl(2)O(2) cross section values with the Pope et al. study is discussed. Representative, atmospheric photolysis rate coefficients are calculated and a range of uncertainty estimated based on the determination of sigma(Cl(2)O(2))(lambda) in this work. Although improvements in our fundamental understanding of the photochemistry of Cl(2)O(2) are still desired, this work indicates that major revisions in current atmospheric chemical mechanisms are not required to simulate observed polar ozone depletion.

UV Absorption Spectrum of the ClO Dimer (Cl2O2) between 200 and 420 nm

NASA Astrophysics Data System (ADS)

Papanastasiou, Dimitrios K.; Papadimitriou, Vassileios C.; Fahey, David W.; Burkholder, James B.

2009-11-01

The UV photolysis of Cl2O2 (dichlorine peroxide) is a key step in the catalytic destruction of polar stratospheric ozone. In this study, the gas-phase UV absorption spectrum of Cl2O2 was measured using diode array spectroscopy and absolute cross sections, σ, are reported for the wavelength range 200-420 nm. Pulsed laser photolysis of Cl2O at 248 nm or Cl2/Cl2O mixtures at 351 nm at low temperature (200-228 K) and high pressure (˜700 Torr, He) was used to produce ClO radicals and subsequently Cl2O2 via the termolecular ClO self-reaction. The Cl2O2 spectrum was obtained from spectra recorded following the completion of the gas-phase ClO radical chemistry. The spectral analysis used observed isosbestic points at 271, 312.9, and 408.5 nm combined with reaction stoichiometry and chlorine mass balance to determine the Cl2O2 spectrum. The Cl2O2 UV absorption spectrum peaks at 244.5 nm with a cross section of 7.6-0.5+0.8 × 10-18 cm2 molecule-1 where the quoted error limits are 2σ and include estimated systematic errors. The Cl2O2 absorption cross sections obtained for wavelengths in the range 300-420 nm are in good agreement with the Cl2O2 spectrum reported previously by Burkholder et al. (J. Phys. Chem. A 1990, 94, 687) and significantly higher than the values reported by Pope et al. (J. Phys. Chem. A 2007, 111, 4322). A possible explanation for the discrepancy in the Cl2O2 cross section values with the Pope et al. study is discussed. Representative, atmospheric photolysis rate coefficients are calculated and a range of uncertainty estimated based on the determination of σCl2O2(λ) in this work. Although improvements in our fundamental understanding of the photochemistry of Cl2O2 are still desired, this work indicates that major revisions in current atmospheric chemical mechanisms are not required to simulate observed polar ozone depletion.

[Study on transient absorption spectrum of tungsten nanoparticle with HepG2 tumor cell].

PubMed

Cao, Lin; Shu, Xiao-Ning; Liang, Dong; Wang, Cong

2014-07-01

Significance of this study lies in tungsten nano materials can be used as a preliminary innovative medicines applied basic research. This paper investigated the inhibition of tungsten nanoparticles which effected on human hepatoma HepG2 cells by MTT. The authors use transient absorption spectroscopy (TAS) technology absorption and emission spectra characterization of charge transfer between nanoparticles and tumor cell. The authors discussed the role of the tungsten nanoparticles in the tumor early detection of the disease and its anti-tumor properties. In the HepG2 experiments system, 100-150 microg x mL(-1) is the best drug concentration of anti-tumor activity which recact violently within 6 hours and basically completed in 24 hours. The results showed that transient absorption spectroscopy can be used as tumor detection methods and characterization of charge transfer between nano-biosensors and tumor cells. Tungsten nanoparticles have potential applications as anticancer drugs.

Would the solvent effect be the main cause of band shift in the theoretical absorption spectrum of large lanthanide complexes?

NASA Astrophysics Data System (ADS)

Freire, Ricardo O.; Rodrigues, Nailton M.; Rocha, Gerd B.; Gimenez, Iara F.; da Costa Junior, Nivan B.

2011-06-01

As most reactions take place in solution, the study of solvent effects on relevant molecular properties - either by experimental or theoretical methods - is crucial for the design of new processes and prediction of technological properties. In spite of this, only few works focusing the influence of the solvent nature specifically on the spectroscopic properties of lanthanide complexes can be found in the literature. The present work describes a theoretical study of the solvent effect on the prediction of the absorption spectra for lanthanide complexes, but other possible relevant factors have been also considered such as the molecular geometry and the excitation window used for interaction configuration (CI) calculations. The [Eu(ETA) 2· nH 2O] +1 complex has been chosen as an ideal candidate for this type of study due to its small number of atoms (only 49) and also because the absorption spectrum exhibits a single band. Two Monte Carlo simulations were performed, the first one considering the [Eu(ETA) 2] +1 complex in 400 water molecules, evidencing that the complex presents four coordinated water molecules. The second simulation considered the [Eu(ETA) 2·4H 2O] +1 complex in 400 ethanol molecules, in order to evaluate the solvent effect on the shift of the maximum absorption in calculated spectra, compared to the experimental one. Quantum chemical studies were also performed in order to evaluate the effect of the accuracy of calculated ground state geometry on the prediction of absorption spectra. The influence of the excitation window used for CI calculations on the spectral shift was also evaluated. No significant solvent effect was found on the prediction of the absorption spectrum for [Eu(ETA) 2·4H 2O] +1 complex. A small but significant effect of the ground state geometry on the transition energy and oscillator strength was also observed. Finally it must be emphasized that the absorption spectra of lanthanide complexes can be predicted with great accuracy

Energy Spectrum and Optical Absorption of Isomer No. 11 of C84 Fullerene of C 2 Symmetry Within the Hubbard Model

NASA Astrophysics Data System (ADS)

Murzashev, A. I.; Rumyantsev, I. A.

2018-05-01

Energy spectrum of isomer No. 11 of C84 fullerene of C2 symmetry is calculated within the Hubbard model. Based on the obtained energy spectrum, the optical absorption spectrum is modeled taking into account not only allowed, but also forbidden symmetry transitions. Good qualitative agreement with the experimental data is obtained. This suggests that when studying fullerenes, the intra-site Coulomb interaction of electrons must be taken into account.

The CO2 absorption spectrum in the 2.3 μm transparency window by high sensitivity CRDS: (II) Self-absorption continuum

NASA Astrophysics Data System (ADS)

Mondelain, D.; Vasilchenko, S.; Čermák, P.; Kassi, S.; Campargue, A.

2017-01-01

The CO2 absorption continuum near 2.3 μm is determined for a series of sub atmospheric pressures (250-750 Torr) by high sensitivity Cavity Ring Down Spectroscopy. An experimental procedure consisting in injecting successively a gas flow of CO2 and synthetic air, keeping constant the gas pressure in the CRDS cell, has been developed. This procedure insures a high stability of the spectra baseline by avoiding changes of the optical alignment due to pressure changes. The CO2 continuum was obtained as the difference between the CO2 absorption coefficient and a local lines simulation using a Voigt profile truncated at ±25 cm-1. Following the results of the preceding analysis of the CO2 rovibrational lines (Vasilchenko S et al. J Quant Spectrosc Radiat Transfer 10.1016/j.jqsrt.2016.07.002, a CO2 line list with intensities obtained by variational calculations and empirical line positions was preferred to the HITRAN line list. A quadratic pressure dependence of the absorption continuum is observed, with an average binary absorption coefficient increasing from 2 to 4×10-8 cm-1 amagat-2 between 4320 and 4380 cm-1. The obtained continuum is found in good agreement with a previous measurement using much higher densities (20 amagat) and a low resolution grating spectrograph and is consistent with values currently used in the analysis of Venus spectra.

Nitryl chloride (ClNO2): UV/vis absorption spectrum between 210 and 296 K and O(3P) quantum yield at 193 and 248 nm.

PubMed

Ghosh, Buddhadeb; Papanastasiou, Dimitrios K; Talukdar, Ranajit K; Roberts, James M; Burkholder, James B

2012-06-21

Recent studies have shown that the UV/vis photolysis of nitryl chloride (ClNO2) can be a major source of reactive chlorine in the troposphere. The present work reports measurements of the ClNO2 absorption spectrum and its temperature dependence between 210 and 296 K over the wavelength range 200–475 nm using diode array spectroscopy. The room temperature spectrum obtained in this work was found to be in good agreement with the results from Ganske et al. (J. Geophys. Res. 1992, 97, 7651) over the wavelength range common to both studies (200–370 nm) but differs systematically from the currently recommended spectrum for use in atmospheric models. The present results lead to a decrease in the calculated atmospheric ClNO2 photolysis rate by 30%. Including the temperature dependence of the ClNO2 spectrum decreases the calculated atmospheric photolysis rate at lower temperatures (higher altitudes) even further. A parametrization of the wavelength and temperature dependence of the ClNO2 spectrum is presented. O(3P) quantum yields, Φ(ClNO2)(O), in the photolysis of ClNO2 at 193 and 248 nm were measured at 296 K using pulsed laser photolysis combined with atomic resonance fluorescence detection of O(3P) atoms. Φ(ClNO2)(O)(λ) was found to be 0.67 ± 0.12 and 0.15 ± 0.03 (2σ error limits, including estimated systematic errors) at 193 and 248 nm, respectively, indicating that multiple dissociation channels are active in the photolysis of ClNO2 at these wavelengths. The Φ(ClNO2)(O)(λ) values obtained in this work are discussed in light of previous ClNO2 photodissociation studies and the differences are discussed.

A QM/MM study of the absorption spectrum of harmane in water solution and interacting with DNA: the crucial role of dynamic effects.

PubMed

Etienne, Thibaud; Very, Thibaut; Perpète, Eric A; Monari, Antonio; Assfeld, Xavier

2013-05-02

We present a time-dependent density functional theory computation of the absorption spectra of one β-carboline system: the harmane molecule in its neutral and cationic forms. The spectra are computed in aqueous solution. The interaction of cationic harmane with DNA is also studied. In particular, the use of hybrid quantum mechanics/molecular mechanics methods is discussed, together with its coupling to a molecular dynamics strategy to take into account dynamic effects of the environment and the vibrational degrees of freedom of the chromophore. Different levels of treatment of the environment are addressed starting from purely mechanical embedding to electrostatic and polarizable embedding. We show that a static description of the spectrum based on equilibrium geometry only is unable to give a correct agreement with experimental results, and dynamic effects need to be taken into account. The presence of two stable noncovalent interaction modes between harmane and DNA is also presented, as well as the associated absorption spectrum of harmane cation.

Absorption spectrum of neat liquid benzene and its concentrated solutions in n-hexane from 220 to 170 nm

SciTech Connect

Saik, V.O.; Lipsky, S.

The electronic absorption spectrum of benzene has been obtained by phototransmission measurements over a concentration range from 0.005 M in n-hexane to the neat liquid at 11.2 M and over a spectral range that extends down to 170 nm. Good agreement is obtained with previously reported measurements on the neat liquid. The oscillator strength of the strongly allowed A{sub 1g} {yields} E{sub 1u} transition is maintained at ca. 1.0 as the benzene concentration increases but is accompanied by extensive redistribution of the intensity such that the optical cross section at the position of the absorption maximum (which shifts from 184{submore » .2} nm in dilute solution to 189{sub .5} nm in the neat liquid) reduces by a factor of 2.7. An explanation for these changes in terms of Lorentz field corrections to the complex dielectric constant is developed, and its implication to the assignment of the neat liquid absorption as a collective excitation is considered. 43 refs., 5 figs., 1 tab.« less

Absorption Spectrum of Phytoplankton Pigments Derived from Hyperspectral Remote-Sensing Reflectance

DTIC Science & Technology

2004-01-01

For a data set collected around Baja California with chlorophyll-a concentration ((chl-a)) ranging from 0.16 to 11.3 mg/cubic meter, hyperspectral absorption spectra of phytoplankton pigments were independently inverted from hyperspectral remote - sensing reflectance using a newly...potential of using hyperspectral remote sensing to retrieve both chlorophyll-a and other accessory pigments. (7 figures, 47 refs.)

High-resolution, vacuum-ultraviolet absorption spectrum of boron trifluoride

SciTech Connect

Hughes, Patrick P.; Thompson, Alan K.; Vest, Robert E.

2014-11-21

In the course of investigations of thermal neutron detection based on mixtures of {sup 10}BF{sub 3} with other gases, knowledge was required of the photoabsorption cross sections of {sup 10}BF{sub 3} for wavelengths between 135 and 205 nm. Large discrepancies in the values reported in existing literature led to the absolute measurements reported in this communication. The measurements were made at the SURF III Synchrotron Ultraviolet Radiation Facility at the National Institute of Standards and Technology. The measured absorption cross sections vary from 10{sup −20} cm{sup 2} at 135 nm to less than 10{sup −21} cm{sup 2} in the regionmore » from 165 to 205 nm. Three previously unreported absorption features with resolvable structure were found in the regions 135–145 nm, 150–165 nm, and 190–205 nm. Quantum mechanical calculations, using the TD-B3LYP/aug-cc-pVDZ variant of time-dependent density functional theory implemented in Gaussian 09, suggest that the observed absorption features arise from symmetry-changing adiabatic transitions.« less

[Open-path online monitoring of ambient atmospheric CO2 based on laser absorption spectrum].

PubMed

He, Ying; Zhang, Yu-Jun; Kan, Rui-Feng; Xia, Hui; Geng, Hui; Ruan, Jun; Wang, Min; Cui, Xiao-Juan; Liu, Wen-Qing

2009-01-01

With the conjunction of tunable diode laser absorption spectroscopy technology (TDLAS) and the open long optical path technology, the system designing scheme of CO2 on-line monitoring based on near infrared tunable diode laser absorption spectroscopy technology was discussed in detail, and the instrument for large-range measurement was set up. By choosing the infrared absorption line of CO2 at 1.57 microm whose line strength is strong and suitable for measurement, the ambient atmospheric CO2 was measured continuously with a 30 s temporal resolution at an suburb site in the autumn of 2007. The diurnal atmospheric variations of CO2 and continuous monitoring results were presented. The results show that the variation in CO2 concentration has an obvious diurnal periodicity in suburb where the air is free of interference and contamination. The general characteristic of diurnal variation is that the concentration is low in the daytime and high at night, so it matches the photosynthesis trend. The instrument can detect gas concentration online with high resolution, high sensitivity, high precision, short response time and many other advantages, the monitoring requires no gas sampling, the calibration is easy, and the detection limit is about 4.2 x 10(-7). It has been proved that the system and measurement project are feasible, so it is an effective method for gas flux continuous online monitoring of large range in ecosystem based on TDLAS technology.

Potential Sex Differences Relative to Autism Spectrum Disorder and Metals.

PubMed

Dickerson, Aisha S; Rotem, Ran S; Christian, MacKinsey A; Nguyen, Vy T; Specht, Aaron J

2017-12-01

This study aims to summarize the current body of literature on the relationship between various toxic metals exposures (i.e., aluminum, antimony, arsenic, beryllium, cadmium, chromium, lead, manganese, and nickel) and autism spectrum disorder (ASD), with a focus on potential sex differences in these associations. Sex differences in ASD diagnosis and mutagenic effects of toxic exposures indicate that sex differences may play a major part in the causal relationship of any potential associations seen; however, we were only able to find three studies that reported on sex differences in observed associations with toxic metals exposure and ASD. We also found several studies investigating associations between ASD and metals exposures, including 11 on aluminum, 6 on antimony, 15 on arsenic, 5 on beryllium, 17 on cadmium, 11 on chromium, 25 on lead, 14 on manganese, and 13 on nickel with markers of exposure in hair, urine, blood, teeth, fingernails, and air pollution. Results for each metal were conflicting, but studies on cadmium and lead yielded the highest proportion of studies with positive results (72% and 36%, respectively). Based on our examination of existing literature, the current evidence warrants a considerable need for evaluations of sex differences in future studies assessing the association between metals exposures and ASD. Additionally, failure to account for potential sex differences could result in bias and misinterpretation of exposure-disease relationships.

Cesium Absorption Spectrum Perturbed by Argon: Observation of Non-Lorentzian Wing Properties

DTIC Science & Technology

2012-03-01

vapor phase Cs contained in a heat pipe in order to observe the absorption lines. Two lenses were used to collimate the light through the heat pipe...After passing through the heat pipe, a mirror was used to direct light around a 90 degree turn and then through an f/# matched lens into a monochromator...pipe used here was built by Charles Fox as part of [19]. Brewster’s angle windows were attached to either end of a pipe approximately 1 inch in diameter

Impact of differences in the solar irradiance spectrum on surface reflectance retrieval with different radiative transfer codes

NASA Technical Reports Server (NTRS)

Staenz, K.; Williams, D. J.; Fedosejevs, G.; Teillet, P. M.

1995-01-01

Surface reflectance retrieval from imaging spectrometer data as acquired with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has become important for quantitative analysis. In order to calculate surface reflectance from remotely measured radiance, radiative transfer codes such as 5S and MODTRAN2 play an increasing role for removal of scattering and absorption effects of the atmosphere. Accurate knowledge of the exo-atmospheric solar irradiance (E(sub 0)) spectrum at the spectral resolution of the sensor is important for this purpose. The present study investigates the impact of differences in the solar irradiance function, as implemented in a modified version of 5S (M5S), 6S, and MODTRAN2, and as proposed by Green and Gao, on the surface reflectance retrieved from AVIRIS data. Reflectance measured in situ is used as a basis of comparison.

Low-temperature high-resolution absorption spectrum of 14NH3 in the ν1+ν3 band region (1.51 μm)

NASA Astrophysics Data System (ADS)

Földes, T.; Golebiowski, D.; Herman, M.; Softley, T. P.; Di Lonardo, G.; Fusina, L.

2014-09-01

Jet-cooled spectra of 14NH3 and 15NH3 in natural abundance were recorded using cavity ring-down (CRDS, 6584-6670 cm-1) and cavity enhanced absorption (CEAS, 6530-6700 cm-1) spectroscopy. Line broadening effects in the CRDS spectrum allowed lines with J″-values between 0 and 3 to be identified. Intensity ratios in 14NH3 between the jet-cooled CRDS and literature room-temperature data from Sung et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1066) further assisted the line assignments. Ground state combination differences were extensively used to support the assignments, providing reliable values for J, K and inversion symmetry of the ground state vibrational levels. CEAS data helped in this respect for the lowest J lines, some of which are saturated in the CRDS spectrum. Further information on a/s doublets arose from the observed spectral structures. Thirty-two transitions of 14NH3 were assigned in this way and a limited but significant number (19) of changes in the assignments results, compared to Sung et al. or to Cacciani et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1084). Sixteen known and 25 new low-J transitions were identified for 15NH3 in the CRDS spectrum but the much scarcer literature information did not allow for any more refined assignment. The present line position measurements improve on literature values published for 15NH3 and on some line positions for 14NH3.

The effect of surface irradiance on the absorption spectrum of chromophoric dissolved organic matter in the global ocean

NASA Astrophysics Data System (ADS)

Swan, Chantal M.; Nelson, Norman B.; Siegel, David A.; Kostadinov, Tihomir S.

2012-05-01

The cycling pathways of chromophoric dissolved organic matter (CDOM) within marine systems must be constrained to better assess the impact of CDOM on surface ocean photochemistry and remote sensing of ocean color. Photobleaching, the loss of absorption by CDOM due to light exposure, is the primary sink for marine CDOM. Herein the susceptibility of CDOM to photobleaching by sea surface-level solar radiation was examined in 15 samples collected from wide-ranging open ocean regimes. Samples from the Pacific, Atlantic, Indian and Southern Oceans were irradiated over several days with full-spectrum light under a solar simulator at in situ temperature in order to measure photobleaching rate and derive an empirical matrix, ɛsurf (m-1 μEin-1), which quantifies the effect of surface irradiance on the spectral absorption of CDOM. Irradiation responses among the ocean samples were similar within the ultraviolet (UV) region of the spectrum spanning 300-360 nm, generally exhibiting a decrease in the CDOM absorption coefficient (m-1) and concomitant increase in the CDOM spectral slope parameter, S (nm-1). However, an unexpected irradiation-induced increase in CDOM absorption between approximately 360 and 500 nm was observed for samples from high-nutrient low-chlorophyll (HNLC) environments. This finding was linked to the presence of dissolved nitrate and may explain discrepancies in action spectra for dimethylsulfide (DMS) photobleaching observed between the Equatorial Pacific and Subtropical North Atlantic Oceans. The nitrate-to-phosphate ratio explained 27-70% of observed variability in ɛsurf at observation wavelengths of 330-440 nm, while the initial spectral slope of the samples explained up to 52% of variability in ɛsurf at observation wavelengths of 310-330 nm. These results suggest that the biogeochemical and solar exposure history of the water column, each of which influence the chemical character and thus the spectral quality of CDOM and its photoreactivity, are the

Aerosol Absorption Retrievals from the PACE Broad Spectrum Ocean Color Instrument (OCI)

NASA Technical Reports Server (NTRS)

Mattoo, Shana; Remer, Lorraine A.; Levy, Robert C.; Gupta, Pawan; Ahmad, Ziauddin; Martins, J. Vanderlei; Lima, Adriana Rocha; Torres, Omar

2016-01-01

The PACE (Pre-­Aerosol, Clouds and ocean Ecosystem) mission, anticipated for launch in the early 2020s, is designed to characterize oceanic and atmospheric properties. The primary instrument on-­-board will be a moderate resolution (approximately 1 km nadir) radiometer, called the Ocean Color Instrument (OCI). OCI will provide high spectral resolution (5 nm) from the UV to NIR (350 - 800 nm), with additional spectral bands in the NIR and SWIR. The OCI itself is an excellent instrument for atmospheric objectives, providing measurements across a broad spectral range that in essence combines the capabilities of MODIS and OMI, but with the UV channels from OMI to be available at moderate resolution. (Image credit: PACE Science Definition Team Report). Objective: Can we make use of the UV-­SWIR measurements to derive information about aerosol absorption when aerosol loading is high?

A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum

NASA Technical Reports Server (NTRS)

Kutyrev, A. S.; Arendt, R.; Dwek, E.; Kimble, R.; Moseley, S. H.; Rapchun, D.; Silverberg, R. F.

2010-01-01

We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance.

Detection of a deep 3-microm absorption feature in the spectrum of Amalthea (JV).

PubMed

Takato, Naruhisa; Bus, Schelte J; Terada, Hiroshi; Pyo, Tae-Soo; Kobayashi, Naoto

2004-12-24

Near-infrared spectra of Jupiter's small inner satellites Amalthea and Thebe are similar to those of D-type asteroids in the 0.8- to 2.5-micrometer wavelength range. A deep absorption feature is detected at 3 micrometers in the spectra of the trailing side of Amalthea, which is similar to that of the non-ice components of Callisto and can be attributed to hydrous minerals. These surface materials cannot be explained if the satellite formed at its present orbit by accreting from a circumjovian nebula. Amalthea and Thebe may be the remnants of Jupiter's inflowing building blocks that formed in the outer part or outside of the circumjovian nebula.

Measurement of the vacuum-ultraviolet absorption spectrum of low-k dielectrics using X-ray reflectivity

NASA Astrophysics Data System (ADS)

Choudhury, F. A.; Nguyen, H. M.; King, S. W.; Lee, C. H.; Lin, Y. H.; Fung, H. S.; Chen, C. C.; Li, W.; Benjamin, D.; Blatz, J. M.; Nishi, Y.; Shohet, J. L.

2018-02-01

During plasma processing, low-k dielectrics are exposed to high levels of vacuum ultraviolet (VUV) radiation that can cause severe damage to dielectric materials. The degree and nature of VUV-induced damage depend on the VUV photon energies and fluence. In this work, we examine the VUV-absorption spectrum of low-k organosilicate glass using specular X-ray reflectivity (XRR). Low-k SiCOH films were exposed to synchrotron VUV radiation with energies ranging from 7 to 21 eV, and the density vs. depth profile of the VUV-irradiated films was extracted from fitting the XRR experimental data. The results show that the depth of the VUV-induced damage layer is a function of the photon energy. Between 7 and 11 eV, the depth of the damaged layer decreases sharply from 110 nm to 60 nm and then gradually increases to 85 nm at 21 eV. The maximum VUV absorption in low-k films occurs between 11 and 15 eV. The depth of the damaged layer was found to increase with film porosity.

Shock absorption ability of laminate mouth guards in two different malocclusions using fiber Bragg grating (FBG) sensor.

PubMed

Bhalla, Ashish; Grewal, Navneet; Tiwari, Umesh; Mishra, Vandana; Mehla, Nahar Singh; Raviprakash, Suryanarain; Kapur, Pawan

2013-06-01

The majority of orofacial injuries affect the upper jaw, with the maxillary incisors being most prone to injury, often accounting for as many as 80% of all cases. Children with malocclusion in the anterior segment of the maxilla are more prone to traumatic injuries than those exhibiting normal occlusion, because most often the damaging force impacts directly against the maxillary anterior teeth. Hence, because of the difference of dissipation of the impact force because of the presence or absence of malocclusion, the mouthguard's shock absorption capacity would be influenced by certain factors. In the present study, a unique in vitro experiment utilizing fiber Bragg Grating (FBG) as distributed strain sensors was carried out to evaluate the shock absorption ability of laminate customized mouthguards in two different malocclusions compared with normal occlusion. The impact was produced using a customized pendulum device with three interchangeable impact objects on typhodont models with two different malocclusions and normal occlusion from different heights. Response of gratings was monitored using an optical spectrum analyzer. Strain induced because each impact was determined from the Bragg's wavelength shifts for each grating. For every model, 12 impact strikes were measured using three different impact objects on the two specified sites by releasing the object from two different heights. The laminated mouthguards showed significant variation in shock absorption ability when different malocclusions were compared. Hence, modifications in the original design of the laminated mouthguards should be considered for athletic competitors with malocclusion to provide adequate protection against impact. FBG sensor has shown the unique advantage of high sensitivity to strain measurement and can be used in further studies. The height of the impact is an important variable in determining the shock absorption ability of mouthguards. © 2012 John Wiley & Sons A/S.

Total Absorption Spectroscopy Study of ⁹²Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

SciTech Connect

Sonzogni, A.; Zakari-Issoufou, A. -A.; Fallot, M.

2015-03-09

The accurate determination of the emitted reactor antineutrino flux is still a major challenge for actual and future neutrino experiments at reactors, especially after the evidence of a disagreement between the measured antineutrino energy spectrum by Double Chooz, Daya Bay, and Reno and calculated antineutrino spectra obtained from the conversion of the unique integral beta spectra measured at the ILL reactor. Using nuclear data to compute reactor antineutrino spectra may help understanding this bias, with the study of the underlying nuclear physics. Summation calculations allow identifying a list of nuclei that contribute importantly to the antineutrino energy spectra emitted aftermore » the fission of ²³⁹ ,²⁴¹Pu and ²³⁵ ,²³⁸U, and whose beta decay properties might deserve new measurements. Among these nuclei, ⁹²Rb exhausts by itself about 16% of of the antineutrino energy spectrum emitted by Pressurized Water Reactors in the 5 to 8 MeV range. In this Letter, we report new Total Absorption Spectroscopy (TAS) results for this important contributor. The obtained beta feeding from ⁹²Rb shows beta intensity unobserved before in the 4.5 to 5.5 MeV energy region and gives a ground state to ground state branch of 87.5 % ± 3%. These new data induce a dramatic change in recent summation calculations where a 51% GS to GS branch was considered for ⁹²Rb, increasing the summation antineutrino spectrum in the region nearby the observed bias.The new data still have an important impact on other summation calculations in which more recent data were considered« less

Tracing Acetylene Dissolved in Transformer Oil by Tunable Diode Laser Absorption Spectrum.

PubMed

Ma, Guo-Ming; Zhao, Shu-Jing; Jiang, Jun; Song, Hong-Tu; Li, Cheng-Rong; Luo, Ying-Ting; Wu, Hao

2017-11-02

Dissolved gas analysis (DGA) is widely used in monitoring and diagnosing of power transformer, since the insulation material in the power transformer decomposes gases under abnormal operation condition. Among the gases, acetylene, as a symbol of low energy spark discharge and high energy electrical faults (arc discharge) of power transformer, is an important monitoring parameter. The current gas detection method used by the online DGA equipment suffers from problems such as cross sensitivity, electromagnetic compatibility and reliability. In this paper, an optical gas detection system based on TDLAS technology is proposed to detect acetylene dissolved in transformer oil. We selected a 1530.370 nm laser in the near infrared wavelength range to correspond to the absorption peak of acetylene, while using the wavelength modulation strategy and Herriott cell to improve the detection precision. Results show that the limit of detection reaches 0.49 ppm. The detection system responds quickly to changes of gas concentration and is easily to maintenance while has no electromagnetic interference, cross-sensitivity, or carrier gas. In addition, a complete detection process of the system takes only 8 minutes, implying a practical prospect of online monitoring technology.

Atomic-level molybdenum oxide nanorings with full-spectrum absorption and photoresponsive properties.

PubMed

Yang, Yong; Yang, Yang; Chen, Shuangming; Lu, Qichen; Song, Li; Wei, Yen; Wang, Xun

2017-11-16

Superthin nanostructures, particularly with atomic-level thicknesses, typically display unique optical properties because of their exceptional light-matter interactions. Here, we report a facile strategy for the synthesis of sulfur-doped molybdenum oxide nanorings with an atomic-level size (thickness of 0.5 nm) and a tunable ring-in-ring architecture. These atomic-level nanorings displayed strong photo-absorption in both the visible and infrared-light ranges and acted as a photothermal agent. Under irradiation with an 808 nm laser with an intensity of 1 W/cm 2 , a composite of the nanorings embedded in polydimethylsiloxane showed an ultrafast photothermal effect, delivering a local temperature of up to 400 °C within 20 s, which to the best of our knowledge is the highest temperature by light irradiation reported to date. Meanwhile, the resulting nanorings were also employed as a photoinitiator to remotely induce a visible-light shape memory response, self-healing, reshaping performance and reversible actuation of dynamic three-dimensional structures. This study demonstrates an advancement towards controlling atomic-level-sized nanostructures and achieving greatly enhanced optical performances for optoelectronics.

[Measurements of IR absorption across section and spectrum simulation of lewisite].

PubMed

Zhang, Yuan-peng; Wang, Hai-tao; Zhang, Lin; Yang, Liu; Guo, Xiao-di; Bai, Yun; Sun, Hao

2015-02-01

The vapor infrared transmission spectra of varied concentration of lewisite-1 were measured by a long-path FT-IR spectrometer, and its characteristic frequencies are 814, 930, 1563 cm(-1); their infrared absorption cross section (a) were determined using Beer-Lambert law. The corresponding sigma values are 3.89 +/- 0.01, 1.43 +/- 0.06, 4.47 +/- 0.05 ( X 10(-20) cm2 x molecule(-1)). Two little teeny peaks, 1158, 1288 cm(-1) were found in the measured spectra. Density Functional Theory (DFT) was applied to calculated the infrared spectra of lewisite-1, -2, -3 on a b3lyp/6-311+g(d, p) level by Gauss09 package. The vibration modes were assigned by Gaussview5. 08. The calculated spectra and experimental spectra are in good agreement with each other in 600-1600 cm(-1) range, for the Person's r is 0.9991. The calculated spectra also showed three characteristic frequencies (293, 360, 374 cm(-1)) related to As atom. 0.977 was a scaling factor we determined for lewisite-1 through least-square error and its performance to scale lewisite-1, -2, -3 was acceptable. The results of this work are useful for monitoring environmental atmospheric concentrations of lewisite.

The effect of equalizing landing task demands on sex differences in lower extremity energy absorption.

PubMed

Montgomery, Melissa M; Shultz, Sandra J; Schmitz, Randy J

2014-08-01

Less lean mass and strength may result in greater relative task demands on females compared to males when landing from a standardized height and could explain sex differences in energy absorption strategies. We compared the magnitude of sex differences in energy absorption when task demands were equalized relative to the amount of lower extremity lean mass available to dissipate kinetic energy upon landing. Male-female pairs (n=35) were assessed for lower extremity lean mass with dual-energy X-ray absorptiometry. Relative task demands were calculated when landing from a standardized height. Based on the difference in lower extremity lean mass within each pair, task demands were equalized by increasing the drop height for males. Joint energetics were measured while landing from the two heights. Multivariate repeated measures ANOVAs compared the magnitude of sex differences in joint energetics between conditions. The multivariate test for absolute energy absorption was significant (P<0.01). The magnitude of sex difference in energy absorption was greater at the hip and knee (both P<0.01), but not the ankle (P=0.43) during the equalized condition compared to the standardized and exaggerated conditions (all P<0.01). There was no difference in the magnitude of sex differences between equalized, standardized and exaggerated conditions for relative energy absorption (P=0.18). Equalizing task demands increased the difference in absolute hip and knee energy absorption between sexes, but had no effect on relative joint contributions to total energy absorption. Sex differences in energy absorption are likely influenced by factors other than differences in relative task demands. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of the shock absorption capacities of different mouthguards.

PubMed

Bochnig, Melina Simonetta; Oh, Min-Jung; Nagel, Theresa; Ziegler, Fred; Jost-Brinkmann, Paul-Georg

2017-06-01

In this in vitro study, the protective qualities of different mouthguard types were examined during small hard object collisions. The aim was to investigate inconclusive aspects of hard inserts, nylon nets, and air spaces as reinforcements in the anterior region and the protection qualities of ethylene vinyl acetate (EVA). Five different mouthguards with a labial thickness between 2 mm and 11 mm made of materials of varying stiffness were investigated. As a negative control, the same experiments were performed without a mouthguard. Different combinations of EVA and labial inserts ((polyethylene terephthalate glycol-modified [PETG]), nylon mesh, air space) were tested. Using a stainless steel pendulum device, blows of different energy (0.07-2.85 joules) were applied to the center of the crown of a pivoted tooth in a custom-built jaw model. A laser Doppler vibrometer measured the tooth deflection, while an acceleration sensor attached to the pendulum measured the braking accelerations. Tooth deflection was reduced up to 99.7% compared to no mouthguard, and the braking acceleration was reduced up to 72.2% by increasing the mouthguards' labial thickness in combination with labial inserts of different stiffness and a built-in air space between the front teeth and the mouthguard. The mouthguards made of soft materials (EVA with nylon mesh) showed slightly better protection qualities than the more rigid mouthguards of similar thickness (PETG; P<.05). However, with increasing impact energy, their protective capacities decreased to a greater extent than the stiffer mouthguards. The combination of increased labial thickness and labial inserts of varying stiffness and eventually an air space offers the best protection capacities for hard, small object collisions. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Study on the effects of Ga-2N high co-doping and preferred orientation on the stability, bandgap and absorption spectrum of ZnO

NASA Astrophysics Data System (ADS)

Hou, Qing-Yu; Li, Wen-Cai; Qu, Ling-Feng; Zhao, Chun-Wang

2017-06-01

Currently, the stability and visible light properties of Ga-2N co-doped ZnO systems have been studied extensively by experimental analysis and theoretical calculations. However, previous theoretical calculations arbitrarily assigned Ga- and 2N-doped sites in ZnO. In addition, the most stable and possible doping orientations of doped systems have not been fully and systematically considered. Therefore, in this paper, the electron structure and absorption spectra of the unit cells of doped and pure systems were calculated by first-principles plane-wave ultrasoft pseudopotential with the GGA+U method. Calculations were performed for pure ZnO, Ga-2N supercells heavily co-doped with Zn1-xGaxO1-yNy (x = 0.03125 - 0.0625, y = 0.0625 - 0.125) under different co-doping orientations and conditions, and the Zn16GaN2O14 interstitial model. The results indicated that under different orientations and constant Ga-2N co-doping concentrations, the systems co-doped with Ga-N atoms vertically oriented to the c-axis and with another N atom located in the nearest-neighboring site exhibited higher stability over the others, thus lowering formation energy and facilitating doping. Moreover, Ga-interstitial- and 2N-co-doped ZnO systems easily formed chemical compounds. Increasing co-doping concentration while the co-doping method remained constant decreased doped system volume and lowered formation energies. Meantime, co-doped systems were more stable and doping was facilitated. The bandgap was also narrower and red shifting of the absorption spectrum was more significant. These results agreed with previously reported experimental results. In addition, the absorption spectra of Ga-interstitial- and 2N-co-doped ZnO both blue shifted in the UV region compared with that of the pure ZnO system.

Spectral- and size-resolved mass absorption efficiency of mineral dust aerosols in the shortwave spectrum: a simulation chamber study

NASA Astrophysics Data System (ADS)

Caponi, Lorenzo; Formenti, Paola; Massabó, Dario; Di Biagio, Claudia; Cazaunau, Mathieu; Pangui, Edouard; Chevaillier, Servanne; Landrot, Gautier; Andreae, Meinrat O.; Kandler, Konrad; Piketh, Stuart; Saeed, Thuraya; Seibert, Dave; Williams, Earle; Balkanski, Yves; Prati, Paolo; Doussin, Jean-François

2017-06-01

This paper presents new laboratory measurements of the mass absorption efficiency (MAE) between 375 and 850 nm for 12 individual samples of mineral dust from different source areas worldwide and in two size classes: PM10. 6 (mass fraction of particles of aerodynamic diameter lower than 10.6 µm) and PM2. 5 (mass fraction of particles of aerodynamic diameter lower than 2.5 µm). The experiments were performed in the CESAM simulation chamber using mineral dust generated from natural parent soils and included optical and gravimetric analyses. The results show that the MAE values are lower for the PM10. 6 mass fraction (range 37-135 × 10-3 m2 g-1 at 375 nm) than for the PM2. 5 (range 95-711 × 10-3 m2 g-1 at 375 nm) and decrease with increasing wavelength as λ-AAE, where the Ångström absorption exponent (AAE) averages between 3.3 and 3.5, regardless of size. The size independence of AAE suggests that, for a given size distribution, the dust composition did not vary with size for this set of samples. Because of its high atmospheric concentration, light absorption by mineral dust can be competitive with black and brown carbon even during atmospheric transport over heavy polluted regions, when dust concentrations are significantly lower than at emission. The AAE values of mineral dust are higher than for black carbon (˜ 1) but in the same range as light-absorbing organic (brown) carbon. As a result, depending on the environment, there can be some ambiguity in apportioning the aerosol absorption optical depth (AAOD) based on spectral dependence, which is relevant to the development of remote sensing of light-absorbing aerosols and their assimilation in climate models. We suggest that the sample-to-sample variability in our dataset of MAE values is related to regional differences in the mineralogical composition of the parent soils. Particularly in the PM2. 5 fraction, we found a strong linear correlation between the dust light-absorption properties and

Differences of cadmium absorption and accumulation in selected vegetable crops.

PubMed

Ni, Wu-Zhong; Yang, Xiao-E; Long, Xin-Xian

2002-07-01

A pot experiment and a sandy culture experiment grown with three vegetable crops of Chinese cabbage (B. chinensis L., cv. Zao-Shu 5), winter greens (B. var. rosularis Tsen et Lee, cv. Shang-Hai-Qing) and celery (A. graveolens L. var. dulce DC., cv. Qing-Qin) were conducted, respectively. The initial soil and four incubated soils with different extractable Cd (0.15, 0.89, 1.38, 1.84 and 2.30 mg Cd/kg soil) were used for the pot experiment. Five treatments were designed (0, 0.0625, 0.125, 0.250 and 0.500 mg Cd/L) in nutrient solution in the sandy culture experiment. Each treatment in pot and sandy culture experiments was trireplicated. The objectives of the study were to examine Cd accumulation in edible parts of selected vegetable crops, its correlation with Cd concentrations in vegetable garden soil or in nutrient solution, and evaluate the criteria of Cd pollution in vegetable garden soil and in nutrient solution based on the hygienic limit of Cd in vegetables. Cadmium concentrations in edible parts of the three selected vegetable crops were as follows: 0.01-0.15 mg/kg fresh weight for Chinese cabbage, 0.02-0.17 mg/kg fresh weight for winter greens, and 0.02-0.24 mg/kg fresh weight for celery in the pot experiment, and 0.1-0.4 mg/kg fresh weight for Chinese cabbage, 0.1-1.4 mg/kg fresh weight for winter greens, and 0.05-0.5 mg/kg fresh weight for celery in the pot experiment (except no-Cd treatment). The order of the three test vegetable crops for cadmium accumulation in the edible parts was celery > winter greens > Chinese cabbage in both the pot experiment and the sandy culture experiment. Cadmium accumulation in edible parts or roots of the vegetable crops increased with increasing of cadmium concentration in the medium (soil or nutrient solution). And cadmium concentrations in edible parts of the test vegetable crops were significantly linearly related to the Cd levels in the growth media (soil and nutrient solution). Based on the regression equations

Gender differences in lower extremity kinematics, kinetics and energy absorption during landing.

PubMed

Decker, Michael J; Torry, Michael R; Wyland, Douglas J; Sterett, William I; Richard Steadman, J

2003-08-01

To determine whether gender differences exist in lower extremity joint motions and energy absorption landing strategies between age and skill matched recreational athletes. Mixed factor, repeated measures design. Compared to males, females execute high demand activities in a more erect posture potentially predisposing the anterior cruciate ligament to greater loads and injury. The preferred energy absorption strategy may provide insight for this performance difference. Inverse dynamic solutions estimated lower extremity joint kinematics, kinetics and energetic profiles for twelve males and nine females performing a 60 cm drop landing. Females demonstrated a more erect landing posture and utilized greater hip and ankle joint range of motions and maximum joint angular velocities compared to males. Females also exhibited greater energy absorption and peak powers from the knee extensors and ankle plantar-flexors compared to the males. Examinations of the energy absorption contributions revealed that the knee was the primary shock absorber for both genders, whereas the ankle plantar-flexors muscles was the second largest contributor to energy absorption for the females and the hip extensors muscles for the males. Females may choose to land in a more erect posture to maximize the energy absorption from the joints most proximal to ground contact. Females may be at a greater risk to anterior cruciate ligament injury during landing due to their energy absorption strategy.

Absorption spectrum and absorption cross sections of the 2ν1 band of HO2 between 20 and 760 Torr air in the range 6636 and 6639 cm-1

NASA Astrophysics Data System (ADS)

Assaf, Emmanuel; Liu, Lu; Schoemaecker, Coralie; Fittschen, Christa

2018-05-01

The absorption spectrum of HO2 radicals has been measured in the range 6636-6639 cm-1 at several pressures between 20 and 760 Torr of air. Absolute absorption cross sections of the strongest line at around 6638.2 cm-1 have been determined from kinetic measurements, taking advantage of the well known rate constant of the self-reaction. Peak absorption cross sections of 22.6, 19.5, 14.4, 7.88, 5.12 and 3.23 × 10-20 cm2 were obtained at 20, 50, 100, 200, 400 and 760 Torr, respectively. By fitting these data, an empirical expression has been obtained for the absorption cross section of HO2 in the range 20-760 Torr air: σ6638.2cm-1 = 1.18 × 10-20 + (2.64 × 10-19 × (1-exp (-63.1/p (Torr))) cm2.

Upper limits on the 21 cm power spectrum at z = 5.9 from quasar absorption line spectroscopy

NASA Astrophysics Data System (ADS)

Pober, Jonathan C.; Greig, Bradley; Mesinger, Andrei

2016-11-01

We present upper limits on the 21 cm power spectrum at z = 5.9 calculated from the model-independent limit on the neutral fraction of the intergalactic medium of x_{H I} < 0.06 + 0.05 (1σ ) derived from dark pixel statistics of quasar absorption spectra. Using 21CMMC, a Markov chain Monte Carlo Epoch of Reionization analysis code, we explore the probability distribution of 21 cm power spectra consistent with this constraint on the neutral fraction. We present 99 per cent confidence upper limits of Δ2(k) < 10-20 mK2 over a range of k from 0.5 to 2.0 h Mpc-1, with the exact limit dependent on the sampled k mode. This limit can be used as a null test for 21 cm experiments: a detection of power at z = 5.9 in excess of this value is highly suggestive of residual foreground contamination or other systematic errors affecting the analysis.

Avian species differences in the intestinal absorption of xenobiotics (PCB, dieldrin, Hg2+)

USGS Publications Warehouse

Serafin, J.A.

1984-01-01

1. Intestinal absorption of a polychlorinated biphenyl, dieldrin, and mercury (from HgCl2) was measured in adult Northern bobwhites, Eastern screech owls, American kestrels, black-crowned night-herons and mallards in vivo by an in situ luminal perfusion technique.2. Bobwhites, screech owls and kestrels absorbed much more of each xenobiotic than black-crowned night-herons and mallards.3. Mallards absorbed less dieldrin and mercury than black-crowned night-herons.4. Mercury absorption by kestrels was more than twice that in screech owls and eight times that observed in mallards.5. Pronounced differences in xenobiotic absorption rates between bobwhites, screech owls and kestrels on the one hand, and black-crowned night-herons and mallards on the other, raise the possibility that absorptive ability may be associated with the phylogenetic classification of birds.

[Analysis of inorganic elements in hydroponic Taraxacum mongolicum grown under different spectrum combinations by ICP-AES].

PubMed

Chen, Xiao-li; Morewane, M B; Xue, Xu-zhang; Guo, Wen-zhong; Wang, Li-chun

2015-02-01

Dandelion (Taraxacum mongolicum) was hydroponically cultured in a completely enclosed plant factory, in which fluorescence and LED emitting spectra of different bands were used as the sole light source for plant growth. Effects of spectral component on the growth of dandelion were studied and the contents of ten inorganic elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu and B in dandelion were analyzed by ICP-AES technology. The results showed that: (1) Under the condition of similar photosynthetic active radiation (PAR), single R or combined spectrums of FLRB were beneficial for biomass accumulation, while single B was the contrary; (2) Macroelements content ratio in Taraxacum mongolicum grown under FLwas K:Ca:P:Mg : Na=79.74:32.39:24.32:10.55:1.00, microelements content ratio was Fe:Mn:B:Zn:Cu = 9.28:9.71:3.82:2.08:1.00; (3) Red light (peak at 660 nm) could promote the absorptions of Ca, Fe, Mn, Zn, while absorption of Cu was not closely related to spectral conditions; (4) Thehighest accumulation of Ca, Na, Mn and Zn were obtained in aerial parts of Taraxacum mongolicum plants grown under pure red spectrum R, while the accumulation of the rest six elements reached the highest level under the mixed spectrum FLRB.

Spectral reflectance characteristics of different snow and snow-covered land surface objects and mixed spectrum fitting

USGS Publications Warehouse

Zhang, J.-H.; Zhou, Z.-M.; Wang, P.-J.; Yao, F.-M.; Yang, L.

2011-01-01

The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. The result showed that for a pure snow spectrum, the snow reflectance peaks appeared from visible to 800 nm band locations; there was an obvious absorption valley of snow spectrum near 1030 nm wavelength. Compared with fresh snow, the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300~1300, 1700~1800 and 2200~2300 nm, the lowest was from the compacted snow and frozen ice. For the vegetation and snow mixed spectral characteristics, it was indicated that the spectral reflectance increased for the snow-covered land types(including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350~1300 nm. However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic. In the end, based on the spectrum analysis of snow, vegetation, and mixed snow/vegetation pixels, the mixed spectral fitting equations were established, and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones(correlation coefficient R2=0.9509).

The absorption spectrum of the QSO PKS 2126-158 (z_em =3.27) at high resolution

NASA Astrophysics Data System (ADS)

D'Odorico, V.; Cristiani, S.; D'Odorico, S.; Fontana, A.; Giallongo, E.

1998-01-01

Spectra of the z_em = 3.268 quasar PKS 2126-158 have been obtained in the range lambda lambda 4300-6620 Angstroms with a resolution Rsmallimeq27000 and an average signal-to-noise ratio s/nsmallimeq 25 per resolution element. The list of the identified absorption lines is given together with their fitted column densities and Doppler widths. The modal value of the Doppler parameter distribution for the Lyalpha lines is smallimeq 25 km s(-1) . The column density distribution can be described by a power-law dn / dN ~ N(-beta ) with beta smallimeq 1.5. 12 metal systems have been identified, two of which were previously unknown. In order to make the column densities of the intervening systems compatible with realistic assumptions about the cloud sizes and the silicon to carbon overabundance, it is necessary to assume a jump beyond the He II edge in the spectrum of the UV ionizing background at z smallim 3 a factor 10 larger than the standard predictions for the integrated quasar contribution. An enlarged sample of C IV absorptions (71 doublets) has been used to analyze the statistical properties of this class of absorbers strictly related to galaxies. The column density distribution is well described by a single power-law, with beta =1.64 and the Doppler parameter distribution shows a modal value b_CIV smallimeq 14 km s(-1) . The two point correlation function has been computed in the velocity space for the individual components of C IV features. A significant signal is obtained for scales smaller than 200- 300 km s(-1) , xi (30< Delta v < 90 km\\ s(-1) ) = 33 +/- 3. A trend of decreasing clustering amplitude with decreasing column density is apparent, analogously to what has been observed for Lyalpha lines. Based on observations collected at the European Southern Observatory, La Silla, Chile (ESO No. 2-013-49K). Table 2 is only available in electronic from via anonymous ftp 130.79.128.5 or http://cdsweb.u-strasbg.fr/Abstract.html

The valence and Rydberg states of difluoromethane: A combined experimental vacuum ultraviolet spectrum absorption and theoretical study by ab initio configuration interaction and density functional computations

NASA Astrophysics Data System (ADS)

Palmer, Michael H.; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare

2018-06-01

The vacuum ultraviolet (VUV) spectrum for CH2F2 from a new synchrotron study has been combined with earlier data and subjected to detailed scrutiny. The onset of absorption, band I and also band IV, is resolved into broad vibrational peaks, which contrast with the continuous absorption previously claimed. A new theoretical analysis, using a combination of time dependent density functional theory (TDDFT) calculations and complete active space self-consistent field, leads to a major new interpretation. Adiabatic excitation energies (AEEs) and vertical excitation energies, evaluated by these methods, are used to interpret the spectra in unprecedented detail using theoretical vibronic analysis. This includes both Franck-Condon (FC) and Herzberg-Teller (HT) effects on cold and hot bands. These results lead to the re-assignment of several known excited states and the identification of new ones. The lowest calculated AEE sequence for singlet states is 11B1 ˜ 11A2 < 21B1 < 11A1 < 21A1 < 11B2 < 31A1 < 31B1. These, together with calculated higher energy states, give a satisfactory account of the principal maxima observed in the VUV spectrum. Basis sets up to quadruple zeta valence with extensive polarization are used. The diffuse functions within this type of basis generate both valence and low-lying Rydberg excited states. The optimum position for the site of further diffuse functions in the calculations of Rydberg states is shown to lie on the H-atoms. The routine choice on the F-atoms is shown to be inadequate for both CHF3 and CH2F2. The lowest excitation energy region has mixed valence and Rydberg character. TDDFT calculations show that the unusual structure of the onset arises from the near degeneracy of 11B1 and 11A2 valence states, which mix in symmetric and antisymmetric combinations. The absence of fluorescence in the 10.8-11 eV region contrasts with strong absorption. This is interpreted by the 21B1 and 11A1 states where no fluorescence is calculated for these

The "Chocolate Experiment"--A Demonstration of Radiation Absorption by Different Colored Surfaces

ERIC Educational Resources Information Center

Fung, Dennis

2015-01-01

In the typical "cookbook" experiment comparing the radiation absorption rates of different colored surfaces, students' hands are commonly used as a measurement instrument to demonstrate that dull black and silvery surfaces are good and poor absorbers of radiation, respectively. However, college students are often skeptical about using…

Claudin gene expression patterns do not associate with interspecific differences in paracellular nutrient absorption.

PubMed

Price, Edwin R; Rott, Katherine H; Caviedes-Vidal, Enrique; Karasov, William H

2016-01-01

Bats exhibit higher paracellular absorption of glucose-sized molecules than non-flying mammals, a phenomenon that may be driven by higher permeability of the intestinal tight junctions. The various claudins, occludin, and other proteins making up the tight junctions are thought to determine their permeability properties. Here we show that absorption of the paracellular probe l-arabinose is higher in a bat (Eptesicus fuscus) than in a vole (Microtus pennsylvanicus) or a hedgehog (Atelerix albiventris). Furthermore, histological measurements demonstrated that hedgehogs have many more enterocytes in their intestines, suggesting that bats cannot have higher absorption of arabinose simply by having more tight junctions. We therefore investigated the mRNA levels of several claudins and occludin, because these proteins may affect permeability of tight junctions to macronutrients. To assess the expression levels of claudins per tight junction, we normalized the mRNA levels of the claudins to the constitutively expressed tight junction protein ZO-1, and combined these with measurements previously made in a bat and a rodent to determine if there were among-species differences. Although expression ratios of several genes varied among species, there was not a consistent difference between bats and non-flyers in the expression ratio of any particular gene. Protein expression patterns may differ from mRNA expression patterns, and might better explain differences among species in arabinose absorption. Copyright © 2015 Elsevier Inc. All rights reserved.

Trace gas absorption spectroscopy using laser difference-frequency spectrometer for environmental application

NASA Technical Reports Server (NTRS)

Chen, W.; Cazier, F.; Boucher, D.; Tittel, F. K.; Davies, P. B.

2001-01-01

A widely tunable infrared spectrometer based on difference frequency generation (DFG) has been developed for organic trace gas detection by laser absorption spectroscopy. On-line measurements of concentration of various hydrocarbons, such as acetylene, benzene, and ethylene, were investigated using high-resolution DFG trace gas spectroscopy for highly sensitive detection.

Studies of Water Absorption Behavior of Plant Fibers at Different Temperatures

NASA Astrophysics Data System (ADS)

Saikia, Dip

2010-05-01

Moisture absorption of natural fiber plastic composites is one major concern in their outdoor applications. The absorbed moisture has many detrimental effects on the mechanical performance of these composites. A knowledge of the moisture diffusivity, permeability, and solubility is very much essential for the application of natural fibers as an excellent reinforcement in polymers. An effort has been made to study the water absorption behavior of some natural fibers such as bowstring hemp, okra, and betel nut at different temperatures to improve the long-term performance of composites reinforced with these fibers. The gain in moisture content in the fibers due to water absorption was measured as a function of exposure time at temperatures ranging from 300 K to 340 K. The thermodynamic parameters of the sorption process, such as diffusion coefficients and corresponding activation energies, were estimated.

X-ray absorption spectroscopy to determine originating depth of electrons that form an inelastic background of Auger electron spectrum

NASA Astrophysics Data System (ADS)

Isomura, Noritake; Cui, Yi-Tao; Murai, Takaaki; Oji, Hiroshi; Kimoto, Yasuji

2017-07-01

In Auger electron spectroscopy (AES), the spectral background is mainly due to inelastic scattering of Auger electrons that lose their kinetic energy in a sample bulk. To investigate the spectral components within this background for SiO2(19.3 nm)/Si(100) with known layer thickness, X-ray absorption spectroscopy (XAS) was used in the partial-electron-yield (PEY) mode at several electron kinetic energies to probe the background of the Si KLL Auger peak. The Si K-edge PEY-XAS spectra constituted of both Si and SiO2 components at each kinetic energy, and their component fractions were approximately the same as those derived from the simulated AES background for the same sample structure. The contributions of Auger electrons originating from layers at different depths to the inelastic background could thus be identified experimentally.

The methane absorption spectrum near 1.73 μm (5695-5850 cm-1): Empirical line lists at 80 K and 296 K and rovibrational assignments

NASA Astrophysics Data System (ADS)

Ghysels, M.; Mondelain, D.; Kassi, S.; Nikitin, A. V.; Rey, M.; Campargue, A.

2018-07-01

The methane absorption spectrum is studied at 297 K and 80 K in the center of the Tetradecad between 5695 and 5850 cm-1. The spectra are recorded by differential absorption spectroscopy (DAS) with a noise equivalent absorption of about αmin≈ 1.5 × 10-7 cm-1. Two empirical line lists are constructed including about 4000 and 2300 lines at 297 K and 80 K, respectively. Lines due to 13CH4 present in natural abundance were identified by comparison with a spectrum of pure 13CH4 recorded in the same temperature conditions. About 1700 empirical values of the lower state energy level, Eemp, were derived from the ratios of the line intensities at 80 K and 296 K. They provide accurate temperature dependence for most of the absorption in the region (93% and 82% at 80 K and 296 K, respectively). The quality of the derived empirical values is illustrated by the clear propensity of the corresponding lower state rotational quantum number, Jemp, to be close to integer values. Using an effective Hamiltonian model derived from a previously published ab initio potential energy surface, about 2060 lines are rovibrationnally assigned, adding about 1660 new assignments to those provided in the HITRAN database for 12CH4 in the region.

Solvent effects on the absorption spectrum and first hyperpolarizability of keto-enol tautomeric forms of anil derivatives: A Monte Carlo/quantum mechanics study

SciTech Connect

Adriano Junior, L.; Fonseca, T. L.; Castro, M. A.

2016-06-21

Theoretical results for the absorption spectrum and electric properties of the enol and keto tautomeric forms of anil derivatives in the gas-phase and in solution are presented. The electronic properties in chloroform, acetonitrile, methanol, and water were determined by carrying out sequential Monte Carlo simulations and quantum mechanics calculations based on the time dependent density functional theory and on the second-order Møller–Plesset perturbation theory method. The results illustrate the role played by electrostatic interactions in the electronic properties of anil derivatives in a liquid environment. There is a significant increase of the dipole moment in solution (20%-100%) relative to themore » gas-phase value. Solvent effects are mild for the absorption spectrum and linear polarizability but they can be particularly important for first hyperpolarizability. A large first hyperpolarizability contrast between the enol and keto forms is observed when absorption spectra present intense lowest-energy absorption bands. Dynamic results for the first hyperpolarizability are in qualitative agreement with the available experimental results.« less

Reconstruction of the absorption spectrum of an object spot from the colour values of the corresponding pixel(s) in its digital image: the challenge of algal colours.

PubMed

Coltelli, Primo; Barsanti, Laura; Evangelista, Valter; Frassanito, Anna Maria; Gualtieri, Paolo

2016-12-01

A novel procedure for deriving the absorption spectrum of an object spot from the colour values of the corresponding pixel(s) in its image is presented. Any digital image acquired by a microscope can be used; typical applications are the analysis of cellular/subcellular metabolic processes under physiological conditions and in response to environmental stressors (e.g. heavy metals), and the measurement of chromophore composition, distribution and concentration in cells. In this paper, we challenged the procedure with images of algae, acquired by means of a CCD camera mounted onto a microscope. The many colours algae display result from the combinations of chromophores whose spectroscopic information is limited to organic solvents extracts that suffers from displacements, amplifications, and contraction/dilatation respect to spectra recorded inside the cell. Hence, preliminary processing is necessary, which consists of in vivo measurement of the absorption spectra of photosynthetic compartments of algal cells and determination of spectra of the single chromophores inside the cell. The final step of the procedure consists in the reconstruction of the absorption spectrum of the cell spot from the colour values of the corresponding pixel(s) in its digital image by minimization of a system of transcendental equations based on the absorption spectra of the chromophores under physiological conditions. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Photodissociation dynamics in the first absorption band of pyrrole. I. Molecular Hamiltonian and the Herzberg-Teller absorption spectrum for the A12(π σ* ) ←X˜ 1 A1(π π ) transition

NASA Astrophysics Data System (ADS)

Picconi, David; Grebenshchikov, Sergy Yu.

2018-03-01

This paper opens a series in which the photochemistry of the two lowest πσ* states of pyrrole and their interaction with each other and with the ground electronic state X ˜ are studied using ab initio quantum mechanics. New 24-dimensional potential energy surfaces for the photodissociation of the N-H bond and the formation of the pyrrolyl radical are calculated using the multiconfigurational perturbation theory (CASPT2) for the electronic states X ˜ (π π ) , 11A2(πσ*), and 11B1(πσ*) and locally diabatized. In this paper, the ab initio calculations are described and the photodissociation in the state 11A2(πσ*) is analyzed. The excitation 11 A2←X ˜ is mediated by the coordinate dependent transition dipole moment functions constructed using the Herzberg-Teller expansion. Nuclear dynamics, including 6, 11, and 15 active degrees of freedom, are studied using the multi-configurational time-dependent Hartree method. The focus is on the frequency resolved absorption spectrum as well as on the dissociation time scales and the resonance lifetimes. Calculations are compared with available experimental data. An approximate convolution method is developed and validated, with which absorption spectra can be calculated and assigned in terms of vibrational quantum numbers. The method represents the total absorption spectrum as a convolution of the diffuse spectrum of the detaching H-atom and the Franck-Condon spectrum of the heteroaromatic ring. Convolution calculation requires a minimal quantum chemical input and is a promising tool for studying the πσ* photodissociation in model biochromophores.

Detection of blueshifted emission and absorption and a relativistic iron line in the X-ray spectrum of ESO323-G077

NASA Astrophysics Data System (ADS)

Jiménez-Bailón, E.; Krongold, Y.; Bianchi, S.; Matt, G.; Santos-Lleó, M.; Piconcelli, E.; Schartel, N.

2008-12-01

We report on the X-ray observation of the Seyfert 1 galaxy ESO323-G077 performed with XMM-Newton. The EPIC spectra show a complex spectrum with conspicuous absorption and emission features. The continuum emission can be modelled with a power law with an index of 1.99 +/- 0.02 in the whole XMM-Newton energy band, marginally consistent with typical values of type I objects. An absorption component with an uncommonly high equivalent hydrogen column (nH = 5.82+0.12-0.11 × 1022cm-2) is affecting the soft part of the spectrum. Additionally, two warm absorption components are also present in the spectrum. The lower ionized one, mainly imprinting the soft band of the spectrum, has an ionization parameter of logU = 2.14+0.06-0.07 and an outflowing velocity of v = 3200+600-200kms-1. Two absorption lines located at ~6.7 and ~7.0keV can be modelled with the highly ionized absorber. The ionization parameter and outflowing velocity of the gas measured are logU = 3.26+0.19-0.15 and v = 1700+600-400kms-1, respectively. Four emission lines were also detected in the soft energy band. The most likely explanation for these emission lines is that they are associated with an outflowing gas with a velocity of ~2000kms-1. The data suggest that the same gas which is causing the absorption could also being responsible of these emission features. Finally, the XMM-Newton spectrum shows the presence of a relativistic iron emission line likely originated in the accretion disc of a Kerr black hole with an inclination of ~25°. We propose a model to explain the observed X-ray properties which invokes the presence of a two-phase outflow with cone-like structure and a velocity of the order of 2000- 4000kms-1. The inner layer of the cone would be less ionized, or even neutral, than the outer layer. The inclination angle of the source would be lower than the opening angle of the outflowing cone. Partially based on observations obtained with XMM-Newton, an ESA science mission with instruments and

Phenotypic Differences in Individuals with Autism Spectrum Disorder Born Preterm and at Term Gestation

ERIC Educational Resources Information Center

Bowers, Katherine; Wink, Logan K.; Pottenger, Amy; McDougle, Christopher J.; Erickson, Craig

2015-01-01

The objective of the study was to characterize the phenotype of males and females with autism spectrum disorder born preterm versus those born at term. Descriptive statistical analyses identified differences between male and female autism spectrum disorder subjects born preterm compared to term for several phenotypic characteristics and…

Parent-Reported Differences between School-Aged Girls and Boys on the Autism Spectrum

ERIC Educational Resources Information Center

Sutherland, Rebecca; Hodge, Antoinette; Bruck, Susan; Costley, Debra; Klieve, Helen

2017-01-01

More boys than girls are diagnosed with autism spectrum disorder; however, there are conflicting findings about whether they differ in their presentation. This study involved a survey of parents of school-aged children on the autism spectrum (171 parents of girls and 163 parents of boys) that was distributed via social media. The surveys provided…

Sex Differences in Co-Occurring Conditions of Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Stacy, Maria E.; Zablotsky, Benjamin; Yarger, Heather A.; Zimmerman, Andrew; Makia, Barraw; Lee, Li-Ching

2014-01-01

This study investigated differences in co-occurring diagnoses made in females compared to males with autism spectrum disorders in 913 children (746 males and 167 females) living in the United States with a current autism spectrum disorder diagnosis identified via caregiver-reported data from the National Survey of Children's Health 2007. The…

[Similarities and differences in absorption characteristics and composition of CDOM between Taihu Lake and Chaohu Lake].

PubMed

Shi, Kun; Li, Yun-mei; Wang, Qiao; Yang, Yu; Jin, Xin; Wang, Yan-fei; Zhang, Hong; Yin, Bin

2010-05-01

Field experiments are conducted separately in Taihu Lake and Chaohu Lake on Apr. and Jun. 2009. The changes in absorption spectra of chromophoric dissolved organic matter (CDOM) characteristics are analyzed using spectral differential analysis technology. According the spectral differential characteristic of absorption coefficient; absorption coefficient from 240 to 450 nm is divided into different stages, and the value of spectral slope S is calculated in each stage. In Stage A, S value of CDOM in Taihu Lake and Chaohu Lake are 0.0166-0.0102 nm(-1) [average (0.0132 +/- 0.0017) nm(-1)], 0.029-0.017 nm(-1) [average (0.0214 +/- 0.0024) nm(-1)]. In Stage B, S values are 0.0187-0.0148 nm(-1) [average (0.0169 +/- 0.001) nm(-1)], 0.0179-0.0055 nm(-1) [average (0.0148 +/- 0.002) nm(-1)]. In Stage C, S values are 0.0208-0.0164 nm(-1) [average (0.0186 +/- 0.0009) nm(-1)], 0.0253-0.0161 nm(-1) [average (0.0197 +/- 0.002) nm(-1)]. The results can be concluded as: (1) Absorption coefficient of water in Taihu Lake, and its contribution to absorption of each component is less than that of water in Chaohu Lake, however the standardized absorption coefficient is larger than that in Chaohu Lake. (2) Both in Taihu Lake and Chaohu Lake, derivative spectra of CDOM absorption coefficient reached valley at 260nm, then rise to top at 290 nm, CDOM absorption coefficient can be delivered into three stages. (3) Generally speaking, content of CDOM in Taihu Lake is less than in Chaohu Lake. (4) pectrum slope (S value) of CDOM is related to composition of CDOM, when content of humic acid in CDOM gets higher, S value of Stage B is the most sensitive value, then is the S value of Stage C. Oppositely, S value of Stage B gets the most sensitive value, then is the S value of Stage A; the least sensitive value is in Stage B.

Differences in energy absorption between heads of adults and children in the near field of sources.

PubMed

Schönborn, F; Burkhardt, M; Kuster, N

1998-02-01

This paper was motivated by a recent article in which the levels of electromagnetic energy absorbed in the heads of mobile phone users were compared for children and adults at the frequencies of 835 MHz and 1,900 MHz. Significant differences were found, in particular substantially greater absorption in children's heads at 835 MHz. These findings contradict other studies in which no significant changes had been postulated. The clarification of this issue is crucial to the mobile communications industry since current SAR evaluations as required by the FCC are only performed with phantoms based on the heads of adults. In order to investigate the differences in absorption between adults and children due to their differing anatomies, simulations have been performed using head phantoms based on MRI scans of an adult (voxel size 2 x 2 x 1 mm3) and two children (voxel size 2 x 2 x 1.1 mm3) of the ages of 3 and 7 y. Ten different tissue types were distinguished. The differences in absorption were investigated for the frequencies of 900 MHz and 1,800 MHz using 0.45 lambda dipoles instead of actual mobile phones. These well-defined sources simplified the investigation and facilitated the comparison to previously published data obtained from several numerical and experimental studies on phantoms based on adults. All simulations were performed using a commercial code based on the finite integration technique. The results revealed no significant differences in the absorption of electromagnetic radiation in the near field of sources between adults and children. The same conclusion holds when children are approximated as scaled adults.

Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas

SciTech Connect

Bartnik, A.; Wachulak, P.; Fiedorowicz, H.

2013-11-15

In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUVmore » radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.« less

Numerical indicators of absorption spectra of green leaf extract obtained from plants of different life forms.

PubMed

Koldaev, Vladimir M; Manyakhin, Artem Yu

2018-06-05

The study was carried out using 58 species of terrestrial plants of different life forms at the start of their fruiting stage. Photoreceptive systems of the leaves were assessed by means of unconventional numerical indicators of absorption spectra, relative photoabsorption coefficient, photosynthetic pigments' integral absorption intensity and relative absorption intensity coefficient. As the study showed, the leaves of all trees and light-demanding grasses favoring open spaces, which were subjected to the study were featured by the lowest values of numerical indicators of absorption spectra (NIAS). Shade-demanding grasses, which grow beneath the canopy, by contrast, were featured by the highest NIAS values. These values of the shrub leaves were in between those of light-demanding plants and shade-demanding ones. The results obtained are consistent with modern visions concerning the biochemistry and the physiology of plants' photoreceptive system. It is appropriate to apply the NIAS, which were used in this study and reflect a leaf's photoreceptive properties, as spectrophotometric criteria for monitoring and environmental management of natural plant resources and agricultural plants. Copyright © 2018 Elsevier B.V. All rights reserved.

Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models.

PubMed

Martínez-Fernández, L; Pepino, A J; Segarra-Martí, J; Banyasz, A; Garavelli, M; Improta, R

2016-09-13

The optical spectra of 5-methylcytidine in three different solvents (tetrahydrofuran, acetonitrile, and water) is measured, showing that both the absorption and the emission maximum in water are significantly blue-shifted (0.08 eV). The absorption spectra are simulated based on CAM-B3LYP/TD-DFT calculations but including solvent effects with three different approaches: (i) a hybrid implicit/explicit full quantum mechanical approach, (ii) a mixed QM/MM static approach, and (iii) a QM/MM method exploiting the structures issuing from molecular dynamics classical simulations. Ab-initio Molecular dynamics simulations based on CAM-B3LYP functionals have also been performed. The adopted approaches all reproduce the main features of the experimental spectra, giving insights on the chemical-physical effects responsible for the solvent shifts in the spectra of 5-methylcytidine and providing the basis for discussing advantages and limitations of the adopted solvation models.

Alligators and Crocodiles Have High Paracellular Absorption of Nutrients, But Differ in Digestive Morphology and Physiology.

PubMed

Tracy, Christopher R; McWhorter, Todd J; Gienger, C M; Starck, J Matthias; Medley, Peter; Manolis, S Charlie; Webb, Grahame J W; Christian, Keith A

2015-12-01

Much of what is known about crocodilian nutrition and growth has come from animals propagated in captivity, but captive animals from the families Crocodilidae and Alligatoridae respond differently to similar diets. Since there are few comparative studies of crocodilian digestive physiology to help explain these differences, we investigated young Alligator mississippiensis and Crocodylus porosus in terms of (1) gross and microscopic morphology of the intestine, (2) activity of the membrane-bound digestive enzymes aminopeptidase-N, maltase, and sucrase, and (3) nutrient absorption by carrier-mediated and paracellular pathways. We also measured gut morphology of animals over a larger range of body sizes. The two species showed different allometry of length and mass of the gut, with A. mississippiensis having a steeper increase in intestinal mass with body size, and C. porosus having a steeper increase in intestinal length with body size. Both species showed similar patterns of magnification of the intestinal surface area, with decreasing magnification from the proximal to distal ends of the intestine. Although A. mississippiensis had significantly greater surface-area magnification overall, a compensating significant difference in gut length between species meant that total surface area of the intestine was not significantly different from that of C. porosus. The species differed in enzyme activities, with A. mississippiensis having significantly greater ability to digest carbohydrates relative to protein than did C. porosus. These differences in enzyme activity may help explain the differences in performance between the crocodilian families when on artificial diets. Both A. mississippiensis and C. porosus showed high absorption of 3-O methyl d-glucose (absorbed via both carrier-mediated and paracellular transport), as expected. Both species also showed surprisingly high levels of l-glucose-uptake (absorbed paracellularly), with fractional absorptions as high as those

A Combination of Chemometrics and Quantum Mechanics Methods Applied to Analysis of Femtosecond Transient Absorption Spectrum of Ortho-Nitroaniline

PubMed Central

Yi, Jing; Xiong, Ying; Cheng, Kemei; Li, Menglong; Chu, Genbai; Pu, Xuemei; Xu, Tao

2016-01-01

A combination of the advanced chemometrics method with quantum mechanics calculation was for the first time applied to explore a facile yet efficient analysis strategy to thoroughly resolve femtosecond transient absorption spectroscopy of ortho-nitroaniline (ONA), served as a model compound of important nitroaromatics and explosives. The result revealed that the ONA molecule is primarily excited to S3 excited state from the ground state and then ultrafast relaxes to S2 state. The internal conversion from S2 to S1 occurs within 0.9 ps. One intermediate state S* was identified in the intersystem crossing (ISC) process, which is different from the specific upper triplet receiver state proposed in some other nitroaromatics systems. The S1 state decays to the S* one within 6.4 ps and then intersystem crossing to the lowest triplet state within 19.6 ps. T1 was estimated to have a lifetime up to 2 ns. The relatively long S* state and very long-lived T1 one should play a vital role as precursors to various nitroaromatic and explosive photoproducts. PMID:26781083

Iron absorption from beans with different contents of iron, evaluated by stable isotopes.

PubMed

Junqueira-Franco, Márcia Varella Morandi; Dutra de Oliveira, José Eduardo; Nutti, Marilia Regini; Pereira, Helton Santos; Carvalho, José Luiz Vianna de; Abrams, Steven A; Brandão, Camila Fernanda Cunha; Marchini, Júlio Sérgio

2018-06-01

The introduction of biofortified foods such as beans with higher iron content may be a useful tool in preventing iron deficiency. The biofortification aims to reach the root of the problem of malnutrition, targets the neediest population, uses embedded distribution mechanisms, is scientifically feasible and effective in terms of cost, and complements other ongoing interventions to control micronutrient deficiency. However, to ensure effectiveness, measurement of the absorption of minerals is essential. The objective of this study was to evaluate the iron bioavailability of common bean BRS Pontal (PO), targeted for biofortification, compared with common bean BRS Estilo in man through reliable techniques that have not been previously used in Brazil. The study included 29 young adult volunteers divided into 2 groups: Group CB (13 subjects) received 100 g of common beans (BRS-Estilo) cooked labeled with iron-58 ( 58 Fe) and Group TBB (16 patients) received 100 g common bean target for iron biofortification (BRS-Pontal), cooked and labeled with iron58 ( 58 Fe). The next day they received the reference dose of ferrous sulfate enriched iron-57 ( 57 Fe). Isotopic evaluation of iron for measurement of iron incorporation into erythrocytes was performed 14 days after consumption. The beans used, were produced, through conventional breeding program, by EMBRAPA/Rice and Beans. The iron absorption was evaluated by assessing the isotopic enrichment of the stable isotope. Mean iron absorption from the meal with common beans was 0.409% (±0.040%) and mean iron incorporation from the meal with target beans for biofortification 0.407% (±0.038%) and did not differ between the groups. This study tested the iron absorption from a single bean meal in healthy volunteers or non anemics, In the present study the iron absorption ratio from common bean Pontal (PO), targeted for biofortification and compared with common bean BRS Estilo was not significantly different. The iron concentration

Levels of cadmium, lead and zinc protoporphyrin absorption in different risk groups.

PubMed

Aurelio, L M; Pilar, D L; Fulgencio, G G; Adoración, P B; Enrique, G C; Alicia, H M; Aurelio, L M

1993-12-01

We studied groups of workers, of pregnant women and of neonates exposed and unexposed to cadmium and lead at their place of work or in the environment. A total of 118 exposed and 28 unexposed workers were studied, together with 90 exposed and 100 unexposed pregnant women and neonates. Concentrations of cadmium and lead in the blood were determined by atomic absorption spectrophotometry. There were significant differences in cadmium concentrations between workers and neonates, and significant differences in lead concentrations between workers and pregnant women. We believe these differences are due mainly to high levels of pollution in the area studied.

Electromagnetic resonance modes on a two-dimensional tandem grating and its application for broadband absorption in the visible spectrum.

PubMed

Han, Sunwoo; Lee, Bong Jae

2016-01-25

In this work, we numerically investigate the electromagnetic resonances on two-dimensional tandem grating structures. The base of a tandem grating consists of an opaque Au substrate, a SiO(2) spacer, and a Au grating (concave type); that is, a well-known fishnet structure forming Au/SiO(2)/Au stack. A convex-type Au grating (i.e., topmost grating) is then attached on top of the base fishnet structure with or without additional SiO(2) spacer, resulting in two types of tandem grating structures. In order to calculate the spectral reflectance and local magnetic field distribution, the finite-difference time-domain method is employed. When the topmost Au grating is directly added onto the base fishnet structure, the surface plasmon and magnetic polariton in the base structure are branched out due to the geometric asymmetry with respect to the SiO(2) spacer. If additional SiO(2) spacer is added between the topmost Au grating and the base fishnet structure, new magnetic resonance modes appear due to coupling between two vertically aligned Au/SiO(2)/Au stacks. With the understanding of multiple electromagnetic resonance modes on the proposed tandem grating structures, we successfully design a broadband absorber made of Au and SiO(2) in the visible spectrum.

Mid-infrared multi-mode absorption spectroscopy, MUMAS, using difference frequency generation

NASA Astrophysics Data System (ADS)

Northern, Henry; O'Hagan, Seamus; Hamilton, Michelle L.; Ewart, Paul

2015-03-01

Multi-mode absorption spectroscopy of ammonia and methane at 3.3 μm has been demonstrated using a source of multi-mode mid-infrared radiation based on difference frequency generation. Multi-mode radiation at 1.56 μm from a diode-pumped Er:Yb:glass laser was mixed with a single-mode Nd:YAG laser at 1.06 μm in a periodically poled lithium niobate crystal to produce multi-mode radiation in the region of 3.3 μm. Detection, by direct multi-mode absorption, of NH3 and CH4 is reported for each species individually and also simultaneously in mixtures allowing measurements of partial pressures of each species.

High Resolution Millimeter Wave Absorption Spectroscopy of Flexi- Ble Complex Organic Molecules: Laboratory Spectrum of 1, 2-Butanediol

NASA Astrophysics Data System (ADS)

Maris, Assimo

2017-11-01

The enhancing sensibility of radioastronomical observations allows for detec- tion of complex organic molecules (COMs) with increasing size. Observations performed by the Atacama Large Millimeter Array (ALMA) open up new oppor- tunities to reveal the COMs, at the same time, the huge amount of data collected and the extremely rich surveys represent a challenge for the astrochemistry community. Among all the detected molecules, the diols are object of chemical interest, because of their similarity with important biological building block molecules such as sugar alcohols. The simplest of them, ethylene glycol (EG), is one of the largest COMs detected in space thus far. Lines attributable to the most stable conformer of EG were detected in different environments and recently also the higher energy conformer has been observed both towards IRAS 16293-2422 and the Orion KL. Observations of 1, 2- and 1, 3-propanediol toward Sgr B2 (N-LMH) were attempted as part of the GBT Prebiotic Interstellar Molecule Sur- vey Legacy Project, but no transitions were detected. Although up to now, due the fact that the column densities of molecules tend to decrease with increasing molecular weight, no large diols have been observed in interstellar space, owing to the raising sensitivity of the radioastronomy observations, their future detection can not be excluded. In this context we report, for the first time, the laboratory millimeter spectrum of 1, 2-butanediol (BD) recorded in the 59.6-103.6 GHz frequency region (5.03-2.89 mm). BD (the ethylated form of EG) is a flexible molecule characterized by a great conformational complexity, thus at room condi- tions the population is distributed in a large number of species, leading to a very congested spectrum. This problem has been overcome exploiting the rotational and conformational cooling produced by the supersonic expansion technique. Six conformers of BD, including the global minimum, have been assigned yielding the rotational constants

Measurement of absorption spectrum of deuterium oxide (D{sub 2}O) and its application to signal enhancement in multiphoton microscopy at the 1700-nm window

SciTech Connect

Wang, Yuxin; Wen, Wenhui; Wang, Kai

2016-01-11

1700-nm window has been demonstrated to be a promising excitation window for deep-tissue multiphoton microscopy (MPM). Long working-distance water immersion objective lenses are typically used for deep-tissue imaging. However, absorption due to immersion water at 1700 nm is still high and leads to dramatic decrease in signals. In this paper, we demonstrate measurement of absorption spectrum of deuterium oxide (D{sub 2}O) from 1200 nm to 2600 nm, covering the three low water-absorption windows potentially applicable for deep-tissue imaging (1300 nm, 1700 nm, and 2200 nm). We apply this measured result to signal enhancement in MPM at the 1700-nm window. Compared with water immersion, D{sub 2}O immersionmore » enhances signal levels in second-harmonic generation imaging, 3-photon fluorescence imaging, and third-harmonic generation imaging by 8.1, 24.8, and 24.7 times with 1662-nm excitation, in good agreement with theoretical calculation based on our absorption measurement. This suggests D{sub 2}O a promising immersion medium for deep-tissue imaging.« less

The Spectrum of Differences between Childhood and Adulthood Celiac Disease

PubMed Central

Ciccocioppo, Rachele; Kruzliak, Peter; Cangemi, Giuseppina C.; Pohanka, Miroslav; Betti, Elena; Lauret, Eugenia; Rodrigo, Luis

2015-01-01

An old saying states that ‘’children are not little adults” and this certainly holds true for celiac disease, as there are many peculiar aspects regarding its epidemiology, diagnosis, clinical presentations, associated diseases, and response to treatment in pediatric compared to adult populations, to such an extent that it merits a description of its own. In fact, contrary to the past when it was thought that celiac disease was a disorder predominantly affecting childhood and characterized by a malabsorption syndrome, nowadays it is well recognized that it affects also adult and elderly people with an impressive variability of clinical presentation. In general, the clinical guidelines for diagnosis recommend starting with specific serologic testing in all suspected subjects, including those suffering from extraintestinal related conditions, and performing upper endoscopy with appropriate biopsy sampling of duodenal mucosa in case of positivity. The latter may be omitted in young patients showing high titers of anti-transglutaminase antibodies. The subsequent management of a celiac patient differs substantially depending on the age at diagnosis and should be based on the important consideration that this is a lifelong condition. PMID:26506381

Absence of sex differences in mental rotation performance in autism spectrum disorder.

PubMed

Rohde, Melanie S; Georgescu, Alexandra L; Vogeley, Kai; Fimmers, Rolf; Falter-Wagner, Christine M

2017-08-01

Mental rotation is one of the most investigated cognitive functions showing consistent sex differences. The 'Extreme Male Brain' hypothesis attributes the cognitive profile of individuals with autism spectrum disorder to an extreme version of the male cognitive profile. Previous investigations focused almost exclusively on males with autism spectrum disorder with only limited implications for affected females. This study is the first testing a sample of 12 female adults with high-functioning autism spectrum disorder compared to 14 males with autism spectrum disorder, 12 typically developing females and 14 typically developing males employing a computerised version of the mental rotation test. Reaction time and accuracy served as dependent variables. Their linear relationship with degree of rotation allows separation of rotational aspects of the task, indicated by slopes of the psychometric function, and non-rotational aspects, indicated by intercepts of the psychometric function. While the typical and expected sex difference for rotational task aspects was corroborated in typically developing individuals, no comparable sex difference was found in autism spectrum disorder individuals. Autism spectrum disorder and typically developing individuals did not differ in mental rotation performance. This finding does not support the extreme male brain hypothesis of autism.

Improved model of activation energy absorption for different electrical breakdowns in semi-crystalline insulating polymers

NASA Astrophysics Data System (ADS)

Sima, Wenxia; Jiang, Xiongwei; Peng, Qingjun; Sun, Potao

2018-05-01

Electrical breakdown is an important physical phenomenon in electrical equipment and electronic devices. Many related models and theories of electrical breakdown have been proposed. However, a widely recognized understanding on the following phenomenon is still lacking: impulse breakdown strength which varies with waveform parameters, decrease in the breakdown strength of AC voltage with increasing frequency, and higher impulse breakdown strength than that of AC. In this work, an improved model of activation energy absorption for different electrical breakdowns in semi-crystalline insulating polymers is proposed based on the Harmonic oscillator model. Simulation and experimental results show that, the energy of trapped charges obtained from AC stress is higher than that of impulse voltage, and the absorbed activation energy increases with the increase in the electric field frequency. Meanwhile, the frequency-dependent relative dielectric constant ε r and dielectric loss tanδ also affect the absorption of activation energy. The absorbed activation energy and modified trap level synergistically determine the breakdown strength. The mechanism analysis of breakdown strength under various voltage waveforms is consistent with the experimental results. Therefore, the proposed model of activation energy absorption in the present work may provide a new possible method for analyzing and explaining the breakdown phenomenon in semi-crystalline insulating polymers.

Differences in RF energy absorption in the heads of adults and children.

PubMed

Christ, Andreas; Kuster, Niels

2005-01-01

There has been a long and controversial debate on possible differences in electromagnetic (EM) energy absorption between adults and children during cell phone usage. Some published studies report higher specific absorption rate (SAR) in children and explain this based on smaller head size. More recently, age dependent changes of the dielectric tissue parameters have again ignited the discussion. This study intends to give a comprehensive review of the current state of knowledge about the parameters and mechanisms affecting the exposure of the mobile phone user with special focus on the exposure of children. Discussed are the absorption mechanism, tissue parameters, the effect of the pinna, and the uncertainties associated with head models based on spheroids, scaled adult heads, and magnetic resonance imaging (MRI) data of children. The conclusions of the review do not support the assumption that the energy exposure increases due to smaller heads, but identifies open issues regarding the dielectric tissue parameters and the thickness of the pinna. Copyright 2005 Wiley-Liss, Inc

Do Early Caregiver Concerns Differ for Girls with Autism Spectrum Disorders?

ERIC Educational Resources Information Center

Little, Lauren M.; Wallisch, Anna; Salley, Brenda; Jamison, Rene

2017-01-01

Given that early caregiver concerns may be different for children who go on to receive a diagnosis of autism spectrum disorder versus another developmental disability, early caregiver concerns may differ for girls. Using a community-based sample of children (n = 241), we examined the extent to which gender differences may be related to caregiver…

The absorption, distribution, excretion and toxicity of mesoporous silica nanoparticles in mice following different exposure routes.

PubMed

Fu, Changhui; Liu, Tianlong; Li, Linlin; Liu, Huiyu; Chen, Dong; Tang, Fangqiong

2013-03-01

Mesoporous silica nanoparticles (MSNs) are emerging as one of the promising nanomaterials for biomedical applications, but the nanomaterials-body interaction exposed by different administration routes remained poorly understood. In the present study, a systematic investigation of the absorption, distribution, excretion and toxicity of silica nanoparticles (SNs) with the average size of 110 nm after four different exposure routes including intravenous, hypodermic, intramuscular injection and oral administration to mice were achieved. The results showed that a fraction of the SNs administrated by the intramuscular and hypodermic injection could cross different biological barriers into the liver but with a low absorption rate. Exposing by oral administration, SNs were absorbed into the intestinal tract and persisted in the liver. And SNs administrated by intravenous injection were mainly present in the liver and spleen. In addition, SNs could cause inflammatory response around the injection sites after intramuscular and hypodermic injection. It was also found that SNs were mainly excreted through urine and feces after different exposure routes. This study will be helpful for selecting the appropriate exposed routes for the development of nanomaterials-based drug delivery system for biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Behavioural and cognitive sex/gender differences in autism spectrum condition and typically developing males and females.

PubMed

Hull, Laura; Mandy, William; Petrides, K V

2017-08-01

Studies assessing sex/gender differences in autism spectrum conditions often fail to include typically developing control groups. It is, therefore, unclear whether observed sex/gender differences reflect those found in the general population or are particular to autism spectrum conditions. A systematic search identified articles comparing behavioural and cognitive characteristics in males and females with and without an autism spectrum condition diagnosis. A total of 13 studies were included in meta-analyses of sex/gender differences in core autism spectrum condition symptoms (social/communication impairments and restricted/repetitive behaviours and interests) and intelligence quotient. A total of 20 studies were included in a qualitative review of sex/gender differences in additional autism spectrum condition symptoms. For core traits and intelligence quotient, sex/gender differences were comparable in autism spectrum conditions and typical samples. Some additional autism spectrum condition symptoms displayed different patterns of sex/gender differences in autism spectrum conditions and typically developing groups, including measures of executive function, empathising and systemising traits, internalising and externalising problems and play behaviours. Individuals with autism spectrum conditions display typical sex/gender differences in core autism spectrum condition traits, suggesting that diagnostic criteria based on these symptoms should take into account typical sex/gender differences. However, awareness of associated autism spectrum condition symptoms should include the possibility of different male and female phenotypes, to ensure those who do not fit the 'typical' autism spectrum condition presentation are not missed.

Analyses of Impact of Needle Surface Properties on Estimation of Needle Absorption Spectrum: Case Study with Coniferous Needle and Shoot Samples

PubMed Central

Yang, Bin; Knyazikhin, Yuri; Lin, Yi; Yan, Kai; Chen, Chi; Park, Taejin; Choi, Sungho; Mõttus, Matti; Rautiainen, Miina; Myneni, Ranga B.; Yan, Lei

2017-01-01

Leaf scattering spectrum is the key optical variable that conveys information about leaf absorbing constituents from remote sensing. It cannot be directly measured from space because the radiation scattered from leaves is affected by the 3D canopy structure. In addition, some radiation is specularly reflected at the surface of leaves. This portion of reflected radiation is partly polarized, does not interact with pigments inside the leaf and therefore contains no information about its interior. Very little empirical data are available on the spectral and angular scattering properties of leaf surfaces. Whereas canopy-structure effects are well understood, the impact of the leaf surface reflectance on estimation of leaf absorption spectra remains uncertain. This paper presents empirical and theoretical analyses of angular, spectral, and polarimetric measurements of light reflected by needles and shoots of Pinus koraiensis and Picea koraiensis species. Our results suggest that ignoring the leaf surface reflected radiation can result in an inaccurate estimation of the leaf absorption spectrum. Polarization measurements may be useful to account for leaf surface effects because radiation reflected from the leaf surface is partly polarized, whereas that from the leaf interior is not. PMID:28868160

Play complexity and toy engagement in preschoolers with autism spectrum disorder: Do girls and boys differ?

PubMed

Harrop, Clare; Green, Jonathan; Hudry, Kristelle

2017-01-01

While sex differences in play have been extensively observed in typical development, only a handful of studies have explored this phenomenon in depth with children with autism spectrum disorders. This study explored sex differences in play complexity and toy engagement within caregiver-child interaction samples for preschool-aged children (2-5 years 11 months) with an autism spectrum disorder who were matched to typically developing children on sex and non-verbal development. Overall we found that girls and boys with autism spectrum disorder were largely equivalent in their play complexity. Despite similar play, girls and boys with autism spectrum disorder differed in a number of ways in their toy engagement, replicating traditional gender differences-girls played more with dolls and domestic items (though at lower rates than typically developing girls) and boys played more with the garage and cars (though at lower rates than typically developing boys). Our findings support the importance and utility of examining sex differences in autism spectrum disorder in light of those observed within typical development. © The Author(s) 2016.

Alternative difference analysis scheme combining R -space EXAFS fit with global optimization XANES fit for X-ray transient absorption spectroscopy

SciTech Connect

Zhan, Fei; Tao, Ye; Zhao, Haifeng

Time-resolved X-ray absorption spectroscopy (TR-XAS), based on the laser-pump/X-ray-probe method, is powerful in capturing the change of the geometrical and electronic structure of the absorbing atom upon excitation. TR-XAS data analysis is generally performed on the laser-on minus laser-off difference spectrum. Here, a new analysis scheme is presented for the TR-XAS difference fitting in both the extended X-ray absorption fine-structure (EXAFS) and the X-ray absorption near-edge structure (XANES) regions.R-space EXAFS difference fitting could quickly provide the main quantitative structure change of the first shell. The XANES fitting part introduces a global non-derivative optimization algorithm and optimizes the local structure changemore » in a flexible way where both the core XAS calculation package and the search method in the fitting shell are changeable. The scheme was applied to the TR-XAS difference analysis of Fe(phen) 3spin crossover complex and yielded reliable distance change and excitation population.« less

Alternative difference analysis scheme combining R-space EXAFS fit with global optimization XANES fit for X-ray transient absorption spectroscopy.

PubMed

Zhan, Fei; Tao, Ye; Zhao, Haifeng

2017-07-01

Time-resolved X-ray absorption spectroscopy (TR-XAS), based on the laser-pump/X-ray-probe method, is powerful in capturing the change of the geometrical and electronic structure of the absorbing atom upon excitation. TR-XAS data analysis is generally performed on the laser-on minus laser-off difference spectrum. Here, a new analysis scheme is presented for the TR-XAS difference fitting in both the extended X-ray absorption fine-structure (EXAFS) and the X-ray absorption near-edge structure (XANES) regions. R-space EXAFS difference fitting could quickly provide the main quantitative structure change of the first shell. The XANES fitting part introduces a global non-derivative optimization algorithm and optimizes the local structure change in a flexible way where both the core XAS calculation package and the search method in the fitting shell are changeable. The scheme was applied to the TR-XAS difference analysis of Fe(phen) 3 spin crossover complex and yielded reliable distance change and excitation population.

Parent-reported differences between school-aged girls and boys on the autism spectrum.

PubMed

Sutherland, Rebecca; Hodge, Antoinette; Bruck, Susan; Costley, Debra; Klieve, Helen

2017-08-01

More boys than girls are diagnosed with autism spectrum disorder; however, there are conflicting findings about whether they differ in their presentation. This study involved a survey of parents of school-aged children on the autism spectrum (171 parents of girls and 163 parents of boys) that was distributed via social media. The surveys provided insights regarding the characteristics of boys and girls (as perceived by parents) as well as some demographic information. There were very few differences reported regarding communication and social strengths and difficulties of boys and girls with autism. No differences were reported in the number of boys and girls on the autism spectrum with special interests or repetitive behaviours; however, significant differences were found in the types of special interests with boys and girls showing generally interests along traditional gender lines. Qualitative analysis of open comments indicated that some parents of girls on the autism spectrum described their daughter as trying to hide or mask her difficulties more but no parents of boys on the spectrum described this phenomenon.

A refractory metamaterial absorber for ultra-broadband, omnidirectional and polarization-independent absorption in the UV-NIR spectrum.

PubMed

Huang, Yijia; Liu, Ling; Pu, Mingbo; Li, Xiong; Ma, Xiaoliang; Luo, Xiangang

2018-05-03

In this paper, efficient ultra-broadband absorption from ultraviolet (UV) to near infrared (NIR) is achieved using a metamaterial perfect absorber (MPA) with refractory constituents. Both simulated and experimental results indicate that this proposed MPA exhibits an average absorption over 95% at wavelengths ranging from 200 nm to 900 nm. Besides, owing to the ultrathin thickness and symmetrical topology of this device, it exhibits great angular tolerance up to 60° independent of the incident polarizations. Excellent thermal stability is also demonstrated at high operation temperatures. The physical origin of the ultra-broadband characteristics is mainly based on diffraction/interference engineering at short wavelengths and the anti-reflection effect at long wavelengths. We believe that such a device may find potential applications ranging from photodetection and photothermal energy conversion to ultraviolet protection and thermophotovoltaics.

The molecular structure and absorption spectrum of hydroxy substituted dibenzoylmethanatoboron difluoride in solution: A theoretical and experimental study

NASA Astrophysics Data System (ADS)

Gelfand, Natalia; Freidzon, Alexandra; Fedorenko, Elena

2018-01-01

Electronic spectroscopy and quantum chemistry are used to study the structure and absorption spectra of the hydroxy substituted dibenzoylmethanatoboron difluoride (OHDBMBF2) in solutions. Introducing a hydroxy group in the diketonate moiety allows the dye to form intermolecular complexes with proton acceptors, such as solvents or analytes, thus making it a promising chemical sensor. Our calculations show that donor oxygen-containing solvents break the intramolecular hydrogen bond Osbnd H···Odik and form an intermolecular Osbnd H···Osolv bond thus disrupting the coplanarity of the dye and affecting the position and shape of its absorption bands. The spectra calculated with explicit solvent combined with polarizable continuum model (PCM) better agree with the experiment than those calculated only within PCM.

Brief Report: Phenotypic Differences and Their Relationship to Paternal Age and Gender in Autism Spectrum Disorder

ERIC Educational Resources Information Center

Vierck, Esther; Silverman, Jeremy M.

2015-01-01

Two modes of inheritance have been proposed in autism spectrum disorder, transmission though pre-existing variants and de novo mutations. Different modes may lead to different symptom expressions in affected individuals. De novo mutations become more likely with advancing paternal age suggesting that paternal age may predict phenotypic…

Play Complexity and Toy Engagement in Preschoolers with Autism Spectrum Disorder: Do Girls and Boys Differ?

ERIC Educational Resources Information Center

Harrop, Clare; Green, Jonathan; Hudry, Kristelle

2017-01-01

While sex differences in play have been extensively observed in typical development, only a handful of studies have explored this phenomenon in depth with children with autism spectrum disorders. This study explored sex differences in play complexity and toy engagement within caregiver-child interaction samples for preschool-aged children (2-5…

Sex Differences in Autism Spectrum Disorder: Evidence from a Large Sample of Children and Adolescents

ERIC Educational Resources Information Center

Mandy, William; Chilvers, Rebecca; Chowdhury, Uttom; Salter, Gemma; Seigal, Anna; Skuse, David

2012-01-01

Sex differences have been found amongst toddlers and young children with autism spectrum disorder (ASD). We investigated the presence and stability of these ASD sex differences throughout childhood and adolescence. Participants (N = 325, 52 females; aged 3-18 years) consecutively received an ASD diagnosis at a clinic for assessing high-functioning…

Calculation of color difference and measurement of the spectrum of aerosol based on human visual system

NASA Astrophysics Data System (ADS)

Dai, Mengyan; Liu, Jianghai; Cui, Jianlin; Chen, Chunsheng; Jia, Peng

2017-10-01

In order to solve the problem of the quantitative test of spectrum and color of aerosol, the measurement method of spectrum of aerosol based on human visual system was proposed. The spectrum characteristics and color parameters of three different aerosols were tested, and the color differences were calculated according to the CIE1976-L*a*b* color difference formula. Three tested powders (No 1# No 2# and No 3# ) were dispersed in a plexglass box and turned into aerosol. The powder sample was released by an injector with different dosages in each experiment. The spectrum and color of aerosol were measured by the PRO 6500 Fiber Optic Spectrometer. The experimental results showed that the extinction performance of aerosol became stronger and stronger with the increase of concentration of aerosol. While the chromaticity value differences of aerosols in the experiment were so small, luminance was verified to be the main influence factor of human eye visual perception and contributed most in the three factors of the color difference calculation. The extinction effect of No 3# aerosol was the strongest of all and caused the biggest change of luminance and color difference which would arouse the strongest human visual perception. According to the sensation level of chromatic color by Chinese, recognition color difference would be produced when the dosage of No 1# powder was more than 0.10 gram, the dosage of No 2# powder was more than 0.15 gram, and the dosage of No 3# powder was more than 0.05 gram.

[Determination of inorganic elements in different parts of Sonchus oleraceus L by flame atomic absorption spectrometry].

PubMed

Wang, Nai-Xing; Cui, Xue-Gui; Du, Ai-Qin; Mao, Hong-Zhi

2007-06-01

Flame atomic absorption spectrometry with air-acetylene flame was used for the determination of inorganic metal elements in different parts ( flower, leaf, stem and root) of Sonchus oleraceus L. The contents of Ca, Mg, K, Na, Fe, Mn, Cu, Zn, Cr, Co, Ni, Pb and Cd in the flower, leaf, stem and root of Sonchus oleraceus L were compared. The order from high to low of the additive weight (microg x g(-1)) for the 13 kinds of metal elements is as follows: leaf (77 213.72) > flower (47 927.15) > stem(42 280.99) > root (28 131.18). From the experimental results it was found that there were considerable differences in the contents of the metal elements in different parts, and there were richer contents of Fe, Zn, Mn and Cu in root and flower, which are necessary to human health, than in other parts.

The `Chocolate Experiment' - A Demonstration of Radiation Absorption by Different Colored Surfaces

NASA Astrophysics Data System (ADS)

Fung, Dennis

2015-12-01

In the typical "cookbook" experiment comparing the radiation absorption rates of different colored surfaces, students' hands are commonly used as a measurement instrument to demonstrate that dull black and silvery surfaces are good and poor absorbers of radiation, respectively. However, college students are often skeptical about using their bare hands in this experiment because they learned in early science lessons that skin is not a reliable detector of heat transfer. Moreover, when the experiment is conducted in a school laboratory, it is often difficult for students to perceive the slight differences in heat transfer on the dull black and silvery aluminum leaves attached to their hands. Rather than replacing students' bare hands with such sophisticated apparatus as a data logger and temperature probe, I suggest using a simple (and delicious!) low-cost instrument, i.e., chocolate, which simply melts when it receives radiation.

A study of the H2O absorption line shifts in the visible spectrum region due to air pressure

NASA Technical Reports Server (NTRS)

Grossmann, B. E.; Browell, E. V.; Bykov, A. D.; Kapitanov, V. A.; Korotchenko, E. A.

1990-01-01

Results of measured and calculated shift coefficients are presented for 170 absorption lines of H2O in five vibrational-rotational bands. The measurements have been carried out using highly sensitive laser spectrometers with a resolution of at least 0.01/cm; the calculations are based on the Anderson-Tsao-Curnutte-Frost method. Good agreement is obtained between the theoretical and experimental values of the shift coefficients of H2O lines due to N2, O2, and air pressure.

The Influence of Different Metal Ions on the Absorption Properties of Nano-Nickel Zinc Ferrite

PubMed Central

Ma, Zhijun; Mang, Changye; Weng, Xingyuan; Si, Liwei; Zhao, Haitao

2018-01-01

The hydrothermal method was used to dope different amounts of Co2+, Mn2+, and Cu2+ in nano-nickel zinc ferrite powder. X-ray diffraction (XRD), a scanning electron microscopy (TEM), and a vector network analyzer (VNA) were used to explore the influence of doping on particle size, morphology, and electromagnetic wave absorption performance. Pure nanometer cobalt nickel zinc ferrite phase was prepared using the hydrothermal method with an increasing Co2+ content. Results showed that the grain type structure changed from a spherical structure to an irregular quadrilateral structure with the average particle size increasing from 35 nm to 60 nm. The lattice constant increased from 0.8352 to 0.8404 nm with Co2+ doping. The increasing Co2+ can change the position of the absorption peak, increase the bandwidth of the absorber, and improve the performance of the materials in GHz low frequency. The doping ratio of Mn2+ can affect the size of the lattice constant, but nanocrystals are easy to reunite without improving the electromagnetic loss. However, the absorbance performance decreases. For the doping of Cu2+, there is an agglomeration phenomenon. When the doping quantity is 0.15, the absorbing wave performance becomes better. PMID:29641477

The Influence of Different Metal Ions on the Absorption Properties of Nano-Nickel Zinc Ferrite.

PubMed

Ma, Zhijun; Mang, Changye; Weng, Xingyuan; Zhang, Qi; Si, Liwei; Zhao, Haitao

2018-04-11

The hydrothermal method was used to dope different amounts of Co 2+ , Mn 2+ , and Cu 2+ in nano-nickel zinc ferrite powder. X-ray diffraction (XRD), a scanning electron microscopy (TEM), and a vector network analyzer (VNA) were used to explore the influence of doping on particle size, morphology, and electromagnetic wave absorption performance. Pure nanometer cobalt nickel zinc ferrite phase was prepared using the hydrothermal method with an increasing Co 2+ content. Results showed that the grain type structure changed from a spherical structure to an irregular quadrilateral structure with the average particle size increasing from 35 nm to 60 nm. The lattice constant increased from 0.8352 to 0.8404 nm with Co 2+ doping. The increasing Co 2+ can change the position of the absorption peak, increase the bandwidth of the absorber, and improve the performance of the materials in GHz low frequency. The doping ratio of Mn 2+ can affect the size of the lattice constant, but nanocrystals are easy to reunite without improving the electromagnetic loss. However, the absorbance performance decreases. For the doping of Cu 2+ , there is an agglomeration phenomenon. When the doping quantity is 0.15, the absorbing wave performance becomes better.

Cl2O photochemistry: ultraviolet/vis absorption spectrum temperature dependence and O(3P) quantum yield at 193 and 248 nm.

PubMed

Papanastasiou, Dimitrios K; Feierabend, Karl J; Burkholder, James B

2011-05-28

The photochemistry of Cl(2)O (dichlorine monoxide) was studied using measurements of its UV/vis absorption spectrum temperature dependence and the O((3)P) atom quantum yield, Φ(Cl(2)O)(O)(λ), in its photolysis at 193 and 248 nm. The Cl(2)O UV/vis absorption spectrum was measured over the temperature range 201-296 K between 200 and 500 nm using diode array spectroscopy. Cl(2)O absorption cross sections, σ(Cl(2)O)(λ,T), at temperatures <296 K were determined relative to its well established room temperature values. A wavelength and temperature dependent parameterization of the Cl(2)O spectrum using the sum of six Gaussian functions, which empirically represent transitions from the ground (1)A(1) electronic state to excited states, is presented. The Gaussian functions are found to correlate well with published theoretically calculated vertical excitation energies. O((3)P) quantum yields in the photolysis of Cl(2)O at 193 and 248 nm were measured using pulsed laser photolysis combined with atomic resonance fluorescence detection of O((3)P) atoms. O((3)P) quantum yields were measured to be 0.85 ± 0.15 for 193 nm photolysis at 296 K and 0.20 ± 0.03 at 248 nm, which was also found to be independent of temperature (220-352 K) and pressure (17 and 28 Torr, N(2)). The quoted uncertainties are at the 2σ (95% confidence) level and include estimated systematic errors. ClO radical temporal profiles obtained following the photolysis of Cl(2)O at 248 nm, as reported previously in Feierabend et al. [J. Phys. Chem. A 114, 12052, (2010)], were interpreted to establish a <5% upper-limit for the O + Cl(2) photodissociation channel, which indicates that O((3)P) is primarily formed in the three-body, O + 2Cl, photodissociation channel at 248 nm. The analysis also indirectly provided a Cl atom quantum yield of 1.2 ± 0.1 at 248 nm. The results from this work are compared with previous studies where possible. © 2011 American Institute of Physics

Whether the Autism Spectrum Quotient Consists of Two Different Subgroups? Cluster Analysis of the Autism Spectrum Quotient in General Population

ERIC Educational Resources Information Center

Kitazoe, Noriko; Fujita, Naofumi; Izumoto, Yuji; Terada, Shin-ichi; Hatakenaka, Yuhei

2017-01-01

The purpose of this study was to investigate whether the individuals in the general population with high scores on the Autism Spectrum Quotient constituted a single homogeneous group or not. A cohort of university students (n = 4901) was investigated by cluster analysis based on the original five subscales of the Autism Spectrum Quotient. Based on…

Behavior Problems: Differences among Intellectually Disabled Adults with Co-Morbid Autism Spectrum Disorders and Epilepsy

ERIC Educational Resources Information Center

Smith, Kimberly R. M.; Matson, Johnny L.

2010-01-01

Behavior problems such as aggression, property destruction, stereotypy, self-injurious behavior, and other disruptive behavior are commonly observed among adults with intellectual disabilities (ID), autism spectrum disorders (ASD), and epilepsy residing at state-run facilities. However, it is unknown how these populations differ on behavior…

Psychiatric Symptoms in Children Diagnosed with an Autism Spectrum Disorder: An Examination of Gender Differences

ERIC Educational Resources Information Center

Worley, Julie A.; Matson, Johnny L.

2011-01-01

In addition to the triad of impairments experienced by children and adolescents diagnosed with Autism Spectrum Disorders (ASD), they often present with symptoms of psychiatric disorders. To date, very few studies have examined gender differences in regards to psychiatric symptoms in children and adolescents diagnosed with an ASD. Thus, the current…

The Rubber Hand Illusion Reveals Proprioceptive and Sensorimotor Differences in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Paton, Bryan; Hohwy, Jakob; Enticott, Peter G.

2012-01-01

Autism spectrum disorder (ASD) is characterised by differences in unimodal and multimodal sensory and proprioceptive processing, with complex biases towards local over global processing. Many of these elements are implicated in versions of the rubber hand illusion (RHI), which were therefore studied in high-functioning individuals with ASD and a…

[Tobacco quality analysis of industrial classification of different years using near-infrared (NIR) spectrum].

PubMed

Wang, Yi; Xiang, Ma; Wen, Ya-Dong; Yu, Chun-Xia; Wang, Luo-Ping; Zhao, Long-Lian; Li, Jun-Hui

2012-11-01

In this study, tobacco quality analysis of main Industrial classification of different years was carried out applying spectrum projection and correlation methods. The group of data was near-infrared (NIR) spectrum from Hongta Tobacco (Group) Co., Ltd. 5730 tobacco leaf Industrial classification samples from Yuxi in Yunnan province from 2007 to 2010 year were collected using near infrared spectroscopy, which from different parts and colors and all belong to tobacco varieties of HONGDA. The conclusion showed that, when the samples were divided to two part by the ratio of 2:1 randomly as analysis and verification sets in the same year, the verification set corresponded with the analysis set applying spectrum projection because their correlation coefficients were above 0.98. The correlation coefficients between two different years applying spectrum projection were above 0.97. The highest correlation coefficient was the one between 2008 and 2009 year and the lowest correlation coefficient was the one between 2007 and 2010 year. At the same time, The study discussed a method to get the quantitative similarity values of different industrial classification samples. The similarity and consistency values were instructive in combination and replacement of tobacco leaf blending.

Sex Differences in Cognitive Domains and Their Clinical Correlates in Higher-Functioning Autism Spectrum Disorders

ERIC Educational Resources Information Center

Bolte, Sven; Duketis, Eftichia; Poustka, Fritz; Holtmann, Martin

2011-01-01

Despite the skewed sex ratio, few studies have addressed possible cognitive sex differences in autism spectrum disorders (ASDs). This study compared visual attention to detail (ATTD) and selected executive functions (EF) in 35 males and 21 females with higher-functioning ASD and unaffected sibling controls. Females with ASD outperformed males on…

Sensory Clusters of Toddlers with Autism Spectrum Disorders: Differences in Affective Symptoms

ERIC Educational Resources Information Center

Ben-Sasson, A.; Cermak, S. A.; Orsmond, G. I.; Tager-Flusberg, H.; Kadlec, M. B.; Carter, A. S.

2008-01-01

Background: Individuals with autism spectrum disorders (ASDs) show variability in their sensory behaviors. In this study we identified clusters of toddlers with ASDs who shared sensory profiles and examined differences in affective symptoms across these clusters. Method: Using cluster analysis 170 toddlers with ASDs were grouped based on parent…

Psychopathology: Differences among Adults with Intellectually Disabled, Comorbid Autism Spectrum Disorders and Epilepsy

ERIC Educational Resources Information Center

Smith, Kimberly R. M.; Matson, Johnny L.

2010-01-01

The goal of this study was to systematically examine group differences among adults with intellectual disabilities (ID), comorbid autism spectrum disorders (ASD), and epilepsy through a detailed exploration of the characteristics that these disorders present in the area of psychopathology. Previous studies indicating that individuals with ID have…

Patterns of Age-Related Cognitive Differences in Adults with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Powell, Patrick S.; Klinger, Laura G.; Klinger, Mark R.

2017-01-01

Little is known about age-related cognitive differences in autism spectrum disorder (ASD). However, given the overlap in cognitive impairments in ASD to those seen in typical aging, it is possible that adults with ASD will face even greater cognitive difficulties as they age. The current study used a cross-sectional design to examine age-related…

Sex Differences in the Timing of Identification among Children and Adults with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Begeer, Sander; Mandell, David; Wijnker-Holmes, Bernadette; Venderbosch, Stance; Rem, Dorien; Stekelenburg, Fred; Koot, Hans M.

2013-01-01

To examine differences by sex in the timing of identification of individuals with autism spectrum disorders (ASD), survey data were collected in the Netherlands from 2,275 males and females with autistic disorder, Asperger's syndrome and PDD-NOS. Among participants less than 18 years of age, females with Asperger's syndrome were identified later…

Examination of Correlates of Different Imitative Functions in Young Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Ingersoll, Brooke; Meyer, Katherine

2011-01-01

Children with autism spectrum disorders (ASD) have difficulties with social-communication skills, including imitation, language, joint attention, and play. This study investigated whether imitation performance in two different contexts (structured-elicited vs. social-interactive) was differentially related to attention-following, social…

Community-Based Instruction and Differences in Functional Independence of Young Adults with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Johnson, Temperance L.

2014-01-01

Students with significant developmental disabilities who engage in activities outside the classroom appear to have better post-school outcomes in the areas of employability, living skills, and independence. No research has examined whether functional independence was significantly different in graduates with autism spectrum disorder (ASD) who have…

Children with Autistic Spectrum Disorders and Speech-Generating Devices: Communication in Different Activities at Home

ERIC Educational Resources Information Center

Thunberg, Gunilla; Ahlsen, Elisabeth; Sandberg, Annika Dahlgren

2007-01-01

The communication of four children with autistic spectrum disorder was investigated when they were supplied with a speech-generating device (SGD) in three different activities in their home environment: mealtime, story reading and "sharing experiences of the preschool day". An activity based communication analysis, in which collective and…

FE K EMISSION AND ABSORPTION FEATURES IN THE XMM-EPIC SPECTRUM OF THE SEYFERT GALAXY IC 4329A

NASA Technical Reports Server (NTRS)

Markowitz, A.; Reeves, J. N.; Braito, V.

2001-01-01

We present a re-analysis of the XMM-Newton long-look of the X-ray bright Seyfert galaxy IC 4329a. The Fe K bandpass is dominated by two peaks, consistent with emission from neutral or near-neutral Fe Ka and KP. A relativistic diskline model whereby both peaks are the result of one doubly-peaked diskline profile is found to be a poor description of the data. Models using two relativistic disklines are found to describe the emission profile well. A low-inclination, moderately-relativistic dual-diskline model is possible if the contribution from narrow components, due to distant material, is small or absent. A high-inclination, moderately relativistic profile for each peak is possible if there are roughly equal contributions from both the broad and narrow components. Upper limits on Fe XXV and Fe XXVI emission and absorption at the systemic velocity of IC 4329a are obtained. We also present the results of RXTE monitoring of this source obtained so far; the combined XMM-Newton and RXTE data sets allow us to explore the time-resolved spectral behavior of this source on time scales ranging from hours to 2 years. We find no strong evidence for variability of the Fe Ka emission line on any time scale probed, likely due to the minimal level of continuum variability. We detect a narrow absorption line, at a energy of 7.68 keV in the rest frame of the source; its significance has been confirmed using Monte Carlo simulations. This feature is most likely due to absorption from Fe XXVI blueshifted to approximately 0.1c relative to the systemic velocity, making IC 4329a the lowest-redshift AGN known with a high-velocity, highly-ionized outflow component. As is often the case with similar outflows seen in high-luminosity quasars, the estimated mass outflow rate is larger than the inflow accretion rate, signaling that the outflow represents a substantial portion of the total energy budget of the AGN. The outflow could arise from a radiatively-driven disk wind, or it may be in the

Multimode fiber-optic temperature sensor system based on dual-wavelength difference absorption principle

NASA Astrophysics Data System (ADS)

Zhang, Zaixuan; Lin, Dan; Fang, Xiao; Jing, Shangzhong

1991-08-01

The multimode fiber optical temperature sensor system is a cobalt salt solution (CoCl26H2O) in the isoptopyl alcohol and water thermochromic transducer based on the dual-wavelength difference absorption principle. The digital locking-in detection, the operation of signal division and temperature calibration is operated by IBM PC computer. The measurement temperature range of the fiber-optic sensor system is 30 degree(s)C to 50 degree(s)C, accuracy is +/- 0.15 degree(s)C, and the temperature resolution is 0.02 degree(s)C. The most accurate measurements resulting from repeated stability tests over 6 and 12 hours (40 degree(s)C) are +/- $0.05 degree(s)C and +/- 0.18 degree(s)C, and the temperature mean is displayed in real time.

Discovery of a cyclotron absorption line in the spectrum of the binary X-ray pulsar 4U 1538 - 52 observed by Ginga

NASA Technical Reports Server (NTRS)

Clark, George W.; Woo, Jonathan W.; Nagase, Fumiaki; Makishima, Kazuo; Sakao, Taro

1990-01-01

A cyclotron absorption line near 20 keV has been found in the spectrum of the massive eclipsing binary X-ray pulsar 4U 1538 - 52 in observations with the Ginga observatory. The line is detected throughout the 529 s pulse cycle with a variable equivalent width that has its maximum value during the smaller peak of the two-peak pulse profile. It is found that the profile of the pulse and the phase-dependence of the cyclotron line can be explained qualitatively by a pulsar model based on recent theoretical results on the properties of pencil beams emitted by accretion-heated slabs of magnetized plasma at the magnetic poles of a neutron star. The indicated field at the surface of the neutron star is 1.7 (1 + z) x 10 to the 12th G, where z is the gravitational redshift.

Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

NASA Astrophysics Data System (ADS)

Saturno, Jorge; Pöhlker, Christopher; Massabò, Dario; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditas, Florian; Hrabě de Angelis, Isabella; Morán-Zuloaga, Daniel; Pöhlker, Mira L.; Rizzo, Luciana V.; Walter, David; Wang, Qiaoqiao; Artaxo, Paulo; Prati, Paolo; Andreae, Meinrat O.

2017-08-01

Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP) data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA), which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June-September 2014). The mean absorption coefficient (at 637 nm) during this period was 1.8 ± 2.1 Mm-1, with a maximum of 15.9 Mm-1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS) retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

A New Search for Carbon Monoxide Absorption in the Transmission Spectrum of the Extrasolar Planet HD 209458b

NASA Astrophysics Data System (ADS)

Deming, Drake; Brown, Timothy M.; Charbonneau, David; Harrington, Joseph; Richardson, L. Jeremy

2005-04-01

We have revisited the search for carbon monoxide absorption features in transmission during the transit of the extrasolar planet HD 209458b. In 2002 August-September we acquired a total of 1077 high-resolution spectra (λ/δλ~25,000) in the K-band (2 μm) wavelength region using NIRSPEC on the Keck II telescope during three transits. These data are more numerous and of better quality than the data analyzed in an initial search by Brown et al. Our analysis achieves a sensitivity sufficient to test the degree of CO absorption in the first-overtone bands during transit on the basis of plausible models of the planetary atmosphere. We analyze our observations by comparison with theoretical tangent geometry absorption spectra, computed by adding height-invariant ad hoc temperature perturbations to the model atmosphere of Sudarsky et al. and by treating cloud height as an adjustable parameter. We do not detect CO absorption. The strong 2-0 R-branch lines between 4320 and 4330 cm-1 have depths during transit less than 1.6 parts in 104 in units of the stellar continuum (3 σ limit) at a spectral resolving power of 25,000. Our analysis indicates a weakening similar to that found in the case of sodium, suggesting that a general masking mechanism is at work in the planetary atmosphere. Under the interpretation that this masking is provided by high clouds, our analysis defines the maximum cloud-top pressure (i.e., minimum height) as a function of the model atmospheric temperature. For the relatively hot model used by Charbonneau et al. to interpret their sodium detection, our CO limit requires cloud tops at or above 3.3 mbar, and these clouds must be opaque at a wavelength of 2 μm. High clouds comprised of submicron-sized particles are already present in some models but may not provide sufficient opacity to account for our CO result. Cooler model atmospheres, having smaller atmospheric scale heights and lower CO mixing ratios, may alleviate this problem to some extent

Ultra-wideband microwave absorber by connecting multiple absorption bands of two different-sized hyperbolic metamaterial waveguide arrays.

PubMed

Yin, Xiang; Long, Chang; Li, Junhao; Zhu, Hua; Chen, Lin; Guan, Jianguo; Li, Xun

2015-10-19

Microwave absorbers have important applications in various areas including stealth, camouflage, and antenna. Here, we have designed an ultra-broadband light absorber by integrating two different-sized tapered hyperbolic metamaterial (HMM) waveguides, each of which has wide but different absorption bands due to broadband slow-light response, into a unit cell. Both the numerical and experimental results demonstrate that in such a design strategy, the low absorption bands between high absorption bands with a single-sized tapered HMM waveguide array can be effectively eliminated, resulting in a largely expanded absorption bandwidth ranging from 2.3 to 40 GHz. The presented ultra-broadband light absorber is also insensitive to polarization and robust against incident angle. Our results offer a further step in developing practical artificial electromagnetic absorbers, which will impact a broad range of applications at microwave frequencies.

A full-dimensional multilayer multiconfiguration time-dependent Hartree study on the ultraviolet absorption spectrum of formaldehyde oxide

SciTech Connect

Meng, Qingyong, E-mail: mengqingyong@dicp.ac.cn; Meyer, Hans-Dieter, E-mail: hans-dieter.meyer@pci.uni-heidelberg.de

2014-09-28

Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamicalmore » calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical B{sup ~} {sup 1}A{sup ′}←X{sup ~} {sup 1}A{sup ′} UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc. 134, 20045–20048 (2012); L. Sheps, J. Phys. Chem. Lett. 4, 4201–4205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys. 16, 10438–10443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation.« less

Band selection method based on spectrum difference in targets of interest in hyperspectral imagery

NASA Astrophysics Data System (ADS)

Zhang, Xiaohan; Yang, Guang; Yang, Yongbo; Huang, Junhua

2016-10-01

While hyperspectral data shares rich spectrum information, it has numbers of bands with high correlation coefficients, causing great data redundancy. A reasonable band selection is important for subsequent processing. Bands with large amount of information and low correlation should be selected. On this basis, according to the needs of target detection applications, the spectral characteristics of the objects of interest are taken into consideration in this paper, and a new method based on spectrum difference is proposed. Firstly, according to the spectrum differences of targets of interest, a difference matrix which represents the different spectral reflectance of different targets in different bands is structured. By setting a threshold, the bands satisfying the conditions would be left, constituting a subset of bands. Then, the correlation coefficients between bands are calculated and correlation matrix is given. According to the size of the correlation coefficient, the bands can be set into several groups. At last, the conception of normalized variance is used on behalf of the information content of each band. The bands are sorted by the value of its normalized variance. Set needing number of bands, and the optimum band combination solution can be get by these three steps. This method retains the greatest degree of difference between the target of interest and is easy to achieve by computer automatically. Besides, false color image synthesis experiment is carried out using the bands selected by this method as well as other 3 methods to show the performance of method in this paper.

[Tobacco quality analysis of industrial classification of different producing area using near-infrared (NIR) spectrum].

PubMed

Wang, Yi; Ma, Xiang; Wen, Ya-Dong; Yu, Chun-Xia; Wang, Luo-Ping; Zhao, Long-Lian; Li, Jun-Hui

2012-10-01

In this study, tobacco quality analysis of industrial classification of different producing area was carried out applying spectrum projection and correlation methods. The group of industrial classification data was near-infrared (NIR) spectrum in 2010 year from different tobacco plant parts and colors of Hongta Tobacco (Group) Co., Ltd. 6 064 tobacco leaf samples of 17 classes from Yuxi, Chuxiong and Zhaotong, in Yunnan province and 6 industrial classifications were collected using near infrared spectroscopy, which from different parts and colors and all belong to tobacco varieties of K326. The conclusion showed that, the probability of the grading belonging by the first dimension was 84%, the probability of the producing area belonging by the second dimension was 71%. The study can explain the difference of tobacco quality of industrial classification and producing area by a projection method to get the quantitative similarity values. The quantitative similarity values were instructive in combination of tobacco leaf blending.

An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-mass X-Ray Binary 1A 1744-361

NASA Astrophysics Data System (ADS)

Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

2012-07-01

We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT ~ 1.0 keV) plus power law (Γ ~ 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 ± 0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2-1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km s-1. We find an equivalent width for the line of 27+2 - 3 eV, from which we determine a column density of (7 ± 1) × 1017 cm-2 via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm s-1. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source.

Probing Lewis Acid-Base Interactions with Born-Oppenheimer Molecular Dynamics: The Electronic Absorption Spectrum of p-Nitroaniline in Supercritical CO2.

PubMed

Cabral, Benedito J Costa; Rivelino, Roberto; Coutinho, Kaline; Canuto, Sylvio

2015-07-02

The structure and dynamics of p-nitroaniline (PNA) in supercritical CO2 (scCO2) at T = 315 K and ρ = 0.81 g cm(-3) are investigated by carrying out Born-Oppenheimer molecular dynamics, and the electronic absorption spectrum in scCO2 is determined by time dependent density functional theory. The structure of the PNA-scCO2 solution illustrates the role played by Lewis acid-base (LA-LB) interactions. In comparison with isolated PNA, the ν(N-O) symmetric and asymmetric stretching modes of PNA in scCO2 are red-shifted by -17 and -29 cm(-1), respectively. The maximum of the charge transfer (CT) absorption band of PNA in scSCO2 is at 3.9 eV, and the predicted red-shift of the π → π* electronic transition relative to the isolated gas-phase PNA molecule reproduces the experimental value of -0.35 eV. An analysis of the relationship between geometry distortions and excitation energies of PNA in scCO2 shows that the π → π* CT transition is very sensitive to changes of the N-O bond distance, strongly indicating a correlation between vibrational and electronic solvatochromism driven by LA-LB interactions. Despite the importance of LA-LB interactions to explain the solvation of PNA in scCO2, the red-shift of the CT band is mainly determined by electrostatic interactions.

An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

NASA Technical Reports Server (NTRS)

Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

2012-01-01

We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments

PubMed Central

Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M. Zafi S.; Sheikh, Adil A.; Felemban, Emad; Qaisar, Saad Bin

2016-01-01

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz. PMID:27322263

RF Path and Absorption Loss Estimation for Underwater Wireless Sensor Networks in Different Water Environments.

PubMed

Qureshi, Umair Mujtaba; Shaikh, Faisal Karim; Aziz, Zuneera; Shah, Syed M Zafi S; Sheikh, Adil A; Felemban, Emad; Qaisar, Saad Bin

2016-06-16

Underwater Wireless Sensor Network (UWSN) communication at high frequencies is extremely challenging. The intricacies presented by the underwater environment are far more compared to the terrestrial environment. The prime reason for such intricacies are the physical characteristics of the underwater environment that have a big impact on electromagnetic (EM) signals. Acoustics signals are by far the most preferred choice for underwater wireless communication. Because high frequency signals have the luxury of large bandwidth (BW) at shorter distances, high frequency EM signals cannot penetrate and propagate deep in underwater environments. The EM properties of water tend to resist their propagation and cause severe attenuation. Accordingly, there are two questions that need to be addressed for underwater environment, first what happens when high frequency EM signals operating at 2.4 GHz are used for communication, and second which factors affect the most to high frequency EM signals. To answer these questions, we present real-time experiments conducted at 2.4 GHz in terrestrial and underwater (fresh water) environments. The obtained results helped in studying the physical characteristics (i.e., EM properties, propagation and absorption loss) of underwater environments. It is observed that high frequency EM signals can propagate in fresh water at a shallow depth only and can be considered for a specific class of applications such as water sports. Furthermore, path loss, velocity of propagation, absorption loss and the rate of signal loss in different underwater environments are also calculated and presented in order to understand why EM signals cannot propagate in sea water and oceanic water environments. An optimal solk6ution for underwater communication in terms of coverage distance, bandwidth and nature of communication is presented, along with possible underwater applications of UWSNs at 2.4 GHz.

Radiation absorption in different kinds of tissue analysis: ex vivo study with supercontinuum laser source

NASA Astrophysics Data System (ADS)

Fornaini, Carlo; Merigo, Elisabetta; Selleri, Stefano; Cucinotta, Annamaria

2016-03-01

With the introduction of more and more new wavelengths, one of the main problems of medical laser users was centered on the study of laser-tissue interactions with the aim of determining the ideal wavelength for their treatments. The aim of this ex vivo study was to determine, by means of the utilization of a supercontinuum source, the amount of transmitted energy of different wavelengths in different organ samples obtained by Sprague Dawley rats. Supercontinuum light is generated by exploiting high optical non-linearity in a material and it combines the broadband attributes of a lamp with the spatial coherence and high brightness of laser. Even if the single transmission measurement does not allow us to separate out the respective contribution of scattering and absorption, it gives us an evaluation of the wavelengths not interacting with the tissue. In this way, being possible to determine what of the laser wavelengths are not useful or active in the different kinds of tissue, physicians may choose the proper device for his clinical treatments.

Red shift of the SF6 vibration spectrum induced by the electron absorption: An ab initio study

NASA Astrophysics Data System (ADS)

Tang, Bin; Zhang, Long-Fei; Han, Fang-Yuan; Luo, Zong-Chang; Liang, Qin-Qin; Liu, Chen-Yao; Zhu, Li-Ping; Zhang, Jie-Ming

2018-01-01

As a widely used gas insulator, sulfur hexafluoride (SF6) has a large cross section for electron absorption, which may make the molecule ionized to the -1 charge state in the high-voltage environment. Using ab initio calculations, we show that the absorbed electron is located averagely on the six F atoms, occupying the antibonding level of the s-p σ bonds and increasing the S-F bond length. The ionized SF6- molecule decreases its decomposition energy to only 1.5 eV, much lower than that of the neutral molecule (4.8 eV), which can be understood according to the occupying of the antibonding orbital and thus weakening of the s-p σ bonds. The weakening of the bonds results in an obvious red shift in the vibrational modes of the ionized SF6- molecule by 120-270 cm-1, compared to those of the neutral molecule. The detailed origin of these vibrational modes is analyzed. Since the appearance of the ionized SF6- molecules is before the decomposition reaction of the SF6- molecule into low-fluoride sulfides, this method may improve the sensitivity of the defection of the partial discharge and save more time for the prevention of the insulation failure in advance.

[Spectrum Variance Analysis of Tree Leaves Under the Condition of Different Leaf water Content].

PubMed

Wu, Jian; Chen, Tai-sheng; Pan, Li-xin

2015-07-01

Leaf water content is an important factor affecting tree spectral characteristics. So Exploring the leaf spectral characteristics change rule of the same tree under the condition of different leaf water content and the spectral differences of different tree leaves under the condition of the same leaf water content are not only the keys of hyperspectral vegetation remote sensing information identification but also the theoretical support of research on vegetation spectrum change as the differences in leaf water content. The spectrometer was used to observe six species of tree leaves, and the reflectivity and first order differential spectrum of different leaf water content were obtained. Then, the spectral characteristics of each tree species leaves under the condition of different leaf water content were analyzed, and the spectral differences of different tree species leaves under the condition of the same leaf water content were compared to explore possible bands of the leaf water content identification by hyperspectral remote sensing. Results show that the spectra of each tree leaf have changed a lot with the change of the leaf water content, but the change laws are different. Leaf spectral of different tree species has lager differences in some wavelength range under the condition of same leaf water content, and it provides some possibility for high precision identification of tree species.

Toxic metals distribution in different components of Pakistani and imported cigarettes by electrothermal atomic absorption spectrometer.

PubMed

Kazi, T G; Jalbani, N; Arain, M B; Jamali, M K; Afridi, H I; Sarfraz, R A; Shah, A Q

2009-04-15

It was extensively investigated that a significant flux of toxic metals, along with other toxins, reaches the lungs through smoking. In present study toxic metals (TMs) (Al, Cd, Ni and Pb) were determined in different components of Pakistani local branded and imported cigarettes, including filler tobacco (FT), filter (before and after normal smoking by a single volunteer) and ash by electrothermal atomic absorption spectrometer (ETAAS). Microwave-assisted digestion method was employed. The validity and accuracy of methodology were checked by using certified sample of Virginia tobacco leaves (ICHTJ-cta-VTL-2). The percentages (%) of TMs in different components of cigarette were calculated with respect to their total contents in FT of all branded cigarettes before smoking, while smoke concentration has been calculated by subtracting the filter and ash contents from the filler tobacco content of each branded cigarette. The highest percentage (%) of Al was observed in ash of all cigarettes, with range 97.3-99.0%, while in the case of Cd, a reverse behaviour was observed, as a range of 15.0-31.3% of total contents were left in the ash of all branded cigarettes understudy.

Diagnosis lost: Differences between children who had and who currently have an autism spectrum disorder diagnosis.

PubMed

Blumberg, Stephen J; Zablotsky, Benjamin; Avila, Rosa M; Colpe, Lisa J; Pringle, Beverly A; Kogan, Michael D

2016-10-01

Autism spectrum disorder diagnoses sometimes change due to misdiagnosis, maturation, or treatment. This study uses a probability-based national survey-the Survey of Pathways to Diagnosis and Services-to compare currently diagnosed (n = 1420) and previously diagnosed (n = 187) children aged 6-17 years based on retrospective parental reports of early concerns about their children's development, responses to those concerns by doctors and other healthcare providers, the type of provider who made the first autism spectrum disorder diagnosis, and the autism spectrum disorder subtype diagnoses received (if any). Propensity score matching was used to control for differences between the groups on children's current level of functioning and other current characteristics that may have been related to diagnosis loss. Approximately 13% of the children ever diagnosed with autism spectrum disorder were estimated to have lost the diagnosis, and parents of 74% of them believed it was changed due to new information. Previously diagnosed children were less likely to have parents with early concerns about verbal skills, nonverbal communication, learning, and unusual gestures or movements. They were also less likely to have been referred to and diagnosed by a specialist. Previously diagnosed children were less likely to have ever received a diagnosis of Asperger's disorder or autistic disorder. © The Author(s) 2015.

Effect of iron status on iron absorption in different habitual meals in young south Indian women.

PubMed

Kalasuramath, Suneeta; Kurpad, Anura V; Thankachan, Prashanth

2013-02-01

Iron deficiency (ID) affects a large number of women in India. An inverse relationship exists between iron (Fe) status and Fe absorption. Dietary inhibitory and enhancing factors exert a profound influence on bioavailability of Fe. Although the current recommended dietary allowance (RDA) for Fe is based on 8 per cent bioavailability, it is not clear if this holds good for the usual highly inhibitory Indian diet matrix. This study was aimed to determine Fe absorption from several habitually consumed south Indian food and to evaluate the interaction of Fe status with absorption. Four Fe absorption studies were performed on 60 apparently healthy young women, aged 18-35 years. Based on blood biochemistry, 45 of them were ID and 15 were iron replete (IR). The habitual meals assessed were rice, millet and wheat based meals in the ID subjects and rice based meal alone in the IR subjects. Each subject received the test meal labelled with 3 mg of ⁵⁷Fe and Fe absorption was measured based on erythrocyte incorporation of isotope label 14 days following administration. Mean fractional Fe absorption from the rice, wheat and millet based meals in the ID subjects were 8.3, 11.2 and 4.6 per cent, respectively. Fe absorption from the rice-based meals was 2.5 per cent in IR subjects. Fe absorption is dictated by Fe status from low bioavailability meals. Millet based meals have the lowest bioavailability, while the rice and wheat based meals had moderate to good bioavailability. In millet based meals, it is prudent to consider ways to improve Fe absorption.

Sex Differences in Children with Autism Spectrum Disorder Identified within a High-Risk Infant Cohort

ERIC Educational Resources Information Center

Zwaigenbaum, Lonnie; Bryson, Susan E.; Szatmari, Peter; Brian, Jessica; Smith, Isabel M.; Roberts, Wendy; Vaillancourt, Tracy; Roncadin, Caroline

2012-01-01

Sex differences were examined in 3-year-olds with autism spectrum disorders (ASD) ascertained from a high-risk cohort, and high- and low-risk comparison groups. Participants included 319 high-risk siblings and 129 low-risk controls. Eighty-five siblings were diagnosed with ASD, including 57 of 176 boys (32.4%) and 28 of 143 girls (19.6%), implying…

Time-resolved absorption and hemoglobin concentration difference maps: a method to retrieve depth-related information on cerebral hemodynamics.

NASA Astrophysics Data System (ADS)

Montcel, Bruno; Chabrier, Renée; Poulet, Patrick

2006-12-01

Time-resolved diffuse optical methods have been applied to detect hemodynamic changes induced by cerebral activity. We describe a near infrared spectroscopic (NIRS) reconstruction free method which allows retrieving depth-related information on absorption variations. Variations in the absorption coefficient of tissues have been computed over the duration of the whole experiment, but also over each temporal step of the time-resolved optical signal, using the microscopic Beer-Lambert law.Finite element simulations show that time-resolved computation of the absorption difference as a function of the propagation time of detected photons is sensitive to the depth profile of optical absorption variations. Differences in deoxyhemoglobin and oxyhemoglobin concentrations can also be calculated from multi-wavelength measurements. Experimental validations of the simulated results have been obtained for resin phantoms. They confirm that time-resolved computation of the absorption differences exhibited completely different behaviours, depending on whether these variations occurred deeply or superficially. The hemodynamic response to a short finger tapping stimulus was measured over the motor cortex and compared to experiments involving Valsalva manoeuvres. Functional maps were also calculated for the hemodynamic response induced by finger tapping movements.

Time-resolved absorption and hemoglobin concentration difference maps: a method to retrieve depth-related information on cerebral hemodynamics.

PubMed

Montcel, Bruno; Chabrier, Renée; Poulet, Patrick

2006-12-11

Time-resolved diffuse optical methods have been applied to detect hemodynamic changes induced by cerebral activity. We describe a near infrared spectroscopic (NIRS) reconstruction free method which allows retrieving depth-related information on absorption variations. Variations in the absorption coefficient of tissues have been computed over the duration of the whole experiment, but also over each temporal step of the time-resolved optical signal, using the microscopic Beer-Lambert law.Finite element simulations show that time-resolved computation of the absorption difference as a function of the propagation time of detected photons is sensitive to the depth profile of optical absorption variations. Differences in deoxyhemoglobin and oxyhemoglobin concentrations can also be calculated from multi-wavelength measurements. Experimental validations of the simulated results have been obtained for resin phantoms. They confirm that time-resolved computation of the absorption differences exhibited completely different behaviours, depending on whether these variations occurred deeply or superficially. The hemodynamic response to a short finger tapping stimulus was measured over the motor cortex and compared to experiments involving Valsalva manoeuvres. Functional maps were also calculated for the hemodynamic response induced by finger tapping movements.

[Chromaticity and optical spectrum colorimetry of the tongue color in different syndromes of primary hepatic carcinoma].

PubMed

Xu, Ying; Zeng, Chang-chun; Cai, Xiu-yu; Guo, Rong-ping; Nie, Guang; Jin, Ying

2012-11-01

In this study, the optical data of tongue color of different syndromes in primary hepatic carcinoma (PHC) were detected by optical spectrum colorimetry, and the chromaticity of tongue color was compared and analyzed. The tongue color characteristics of different syndromes in PHC and the relationship between different syndromes and tongue color were also investigated. Tongue color data from 133 eligible PHC patients were collected by optical spectrum colorimetry and the patients were divided into 4 syndrome groups according to their clinical features. The syndrome groups were liver depression and spleen deficiency (LDSD), accumulation of damp-heat (ADH), deficiency of liver and kidney yin (DLKY), and qi stagnation and blood stasis (QSBS). The variation characteristics of chromaticity coordinates, dominant wavelength, excitation purity and the distribution in the International Commission on Illumination (CIE) LAB uniform color space were measured. At the same time, the differences of overall chromatism, clarity, chroma, saturation and hue were also calculated and analyzed. PHC patients in different syndrome groups exhibited differences in chromaticity coordinates. The dominant wavelength of QSBS was distinctly different from that of the other 3 syndromes. Excitation purity in the syndromes of LDSD, ADH and DLKY showed gradual increases (P<0.01). Different syndromes in the CIE LAB color three-dimensional space showed differences in tongue color distribution areas. The CIE hue-angle value of QSBS was negative, and different from that of the other 3 syndromes (P<0.01). CIE chroma in the syndromes of LDSD, ADH and DLKY showed gradual increases (P<0.01), the same as excitation purity. In the comparison of chromatism, tongue color variations in different syndromes were quantified by human observation. This study shows that tongue color diagnosis according to the syndrome classifications of traditional Chinese medicine can be quantified with optical spectrum colorimetry

Numerical and theoretical analysis on the absorption properties of metasurface-based terahertz absorbers with different thicknesses.

PubMed

Wu, Kaimin; Huang, Yongjun; Wanghuang, Tenglong; Chen, Weijian; Wen, Guangjun

2015-01-10

In this paper, we numerically and theoretically discuss the novel absorption properties of a conventional metasurface-based terahertz (THz) electromagnetic (EM) absorber with different dielectric thicknesses. Two absorption modes are presented in the considered frequency band due to the increased dielectric thickness, and both modes can achieve near-unity absorptions when the dielectric layers reach additional nλ(d)/2 (n=1, 2) thicknesses, where λ(d) is the operating wavelength at the peak absorption in the dielectric slabs. The surface currents between the metasurface resonators and ground plane are not associated any longer, different from the conventional thin absorbers. Moreover, the EM wave energies are completely absorbed by the metasurface resonators and dielectric layer, and the main function of ground plane is to reflect the incident EM waves back to the resonators. The discussed novel absorption properties are analyzed and explained by classical EM theory and interference theory after numerical demonstrations. These findings can broaden the potential applications of the metasurface-based absorbers in the THz frequency range for different requirements.

Behavioural and Cognitive Sex/Gender Differences in Autism Spectrum Condition and Typically Developing Males and Females

ERIC Educational Resources Information Center

Hull, Laura; Mandy, William; Petrides, K. V.

2017-01-01

Studies assessing sex/gender differences in autism spectrum conditions often fail to include typically developing control groups. It is, therefore, unclear whether observed sex/gender differences reflect those found in the general population or are particular to autism spectrum conditions. A systematic search identified articles comparing…

The enhancement of 21.2%-power conversion efficiency in polymer photovoltaic cells by using mixed Au nanoparticles with a wide absorption spectrum of 400 nm-1000 nm

NASA Astrophysics Data System (ADS)

Hao, Jing-Yu; Xu, Ying; Zhang, Yu-Pei; Chen, Shu-Fen; Li, Xing-Ao; Wang, Lian-Hui; Huang, Wei

2015-04-01

Au nanoparticles (NPs) mixed with a majority of bone-like, rod, and cube shapes and a minority of irregular spheres, which can generate a wide absorption spectrum of 400 nm-1000 nm and three localized surface plasmon resonance peaks, respectively, at 525, 575, and 775 nm, are introduced into the hole extraction layer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) to improve optical-to-electrical conversion performances in polymer photovoltaic cells. With the doping concentration of Au NPs optimized, the cell performance is significantly improved: the short-circuit current density and power conversion efficiency of the poly(3-hexylthiophene): [6,6]-phenyl-C60-butyric acid methyl ester cell are increased by 20.54% and 21.2%, reaching 11.15 mA·cm-2 and 4.23%. The variations of optical, electrical, and morphology with the incorporation of Au NPs in the cells are analyzed in detail, and our results demonstrate that the cell performance improvement can be attributed to a synergistic reaction, including: 1) both the localized surface plasmon resonance- and scattering-induced absorption enhancement of the active layer, 2) Au doping-induced hole transport/extraction ability enhancement, and 3) large interface roughness-induced efficient exciton dissociation and hole collection. Project supported by the National Basic Research Program of China (Grant Nos. 2015CB932202 and 2012CB933301), the National Natural Science Foundation of China (Grant Nos. 61274065, 51173081, 61136003, BZ2010043, 51372119, and 51172110), the Science Fund from the Ministry of Education of China (Grant No. IRT1148), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20113223110005), the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions (Grant No. YX03001), and the National Synergistic Innovation Center for Advanced Materials and the Synergetic Innovation Center for Organic Electronics and

An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary 1A 1744-361

NASA Technical Reports Server (NTRS)

Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

2009-01-01

We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.

[The change in lipoid spectrum in blood serum in girls of different somatotypes after meals].

PubMed

Fefelova, Iu A

2010-01-01

State Educational Institution for Professional Education - Prof. Voyno-Yasenetzkiy's High School of Krasnoyarsk State Medical Academy of Russian Public Health Ministry. We carried out the analysis of the changes in the spectrum of neutral lipoids and phospholipoids in blood serum as a response to meals in girls of different somatotypes. We revealed statistically true lowering of lipid acids content in representatives of all examined somatotypes after meals. Statistically true increase of simply oxidized fractions of phospholipoids in girls of sub-athletic and athletic somatotypes testifies on the change in the ratio of dynamics components of lipoid spectrum of lipoproteids. Balanced fractions of phospholipoids as well as free cholesterol are the main structural components in lipoproteid membranes and they didn't change in any of the studied somatotypes as a response to meals. This proves the stability of membrane structure of lipoproteid complexes as a response to the given physiological stimulus.

Ingestion, enzymatic digestion and absorption of particles derived from different vegetal sources by the cockle Cerastoderma edule

NASA Astrophysics Data System (ADS)

Arambalza, U.; Urrutia, M. B.; Navarro, E.; Ibarrola, I.

2010-10-01

Ingestion, enzymatic digestion and absorption of particulate detrital matter derived from six different vegetal sources by the common cockle Cerastoderma edule was analyzed in a series of seasonal experiments performed in March, May and October 2005. Two green macroalgae: Ulva lactuca and Enteromorpha sp; two vascular plants: Spartina maritima and Juncus maritimus, the red macroalgae Gracilaria gracilis; and the microalgae Isochrysis galbana were used in experiments. Detrital matter was elaborated by freeze-drying, grinding and sieving (< 63 μm) vegetal tissues. Mono-specific detrital diets of similar organic content (≈ 60-70%) were elaborated by mixing detritus with ashed silt. We measured i) the biochemical composition of different detritus, ii) physiological components of the absorptive balance (i.e. clearance, ingestion, rejection and absorption rate and absorption efficiency), iii) the capability of the digestive gland to hydrolyze carbohydrates from different detritus (digestibility), as well as iv) glandular cellulase and xylanase activities. Detritus type, season and the interaction detritus-season exerted significant effects upon all the physiological components of absorptive balance. Effects were light at the pre-absorptive level, however, huge variations associated to absorption efficiency promoted large significant differences in absorption rates (AR) of different kind of detritus: irrespective of season, highest values corresponded to cockles fed the green macroalgae ( Ulva and Enteromorpha) and lowest to those fed the vascular plant Juncus maritimus. Recorded significant differences in enzymatic digestibility among detritus were found to explain ≈ 40% of differences recorded in AR, and the following regression could be fitted: AR = 0.232 (± 0.032) * Digestibility + 0,072 (± 0.015); r 2 = 0.415; F = 51.036; p < 0.001. Digestibility of Ulva and Enteromorpha was found to be significantly correlated with cellulase activity in the digestive gland

[Infrared Spectrum Analysis of Propolis and Tree Gum Collected from Different Areas].

PubMed

Luo, Huo-lin; Liu, Xing-xing; Gong, Shang-ji; Guo, Xia-li; Luo, Li-ping

2015-11-01

Propolis possesses functions of antibacterial, antiviral, anticancer, and liver protection, and is known as the "purple gold", however, the phenomenon which making and selling of counterfeit are growing in intensity. In order to establish a authenticity and quality of propolis evaluation model, in this paper, forty-one Chinese propolis, one proplis from United States and two tree gums were used for experimental materials. The infrared spectrum collection was performed by Fourier transform infrared spectrometer, and principal component analysis (PCA) was used for data analysis. The result showed that, the intrared spectrum of propolis and tree gum were significantly different. The propolis characteristic peak only appeared in 2500-3500 and 400-1800 cm⁻¹. All propolis had two frequency region of characteristic peaks, 2849.08-2848.53 and 2917.74- 2916.76 cm⁻¹, but tree gum did not have characteristic peak in this region. The characteristic peaks of gum were in 1150-1300 and 1550-1650 cm⁻¹. Differences in these aspects can be used to distinguish propolis and gum, and can be used to identify true and false propolis. We use Qinghai propolis as a standard sample, in 42 samples, the matching degree of other propolis is > 80%. In addition, the result of PCA shows that tree gum and the propolis from different climate zone, or with different colors could be distinguished well. This paper firstly performed analysis on different propolis and gum by infrared spectrum, and a new method, for authenticity and quality of propolis identification, could be developed.

Population differences in dysmorphic features among children with fetal alcohol spectrum disorders.

PubMed

May, Philip A; Gossage, J Phillip; Smith, Matthew; Tabachnick, Barbara G; Robinson, Luther K; Manning, Melanie; Cecanti, Mauro; Jones, Kenneth Lyons; Khaole, Nathaniel; Buckley, David; Kalberg, Wendy O; Trujillo, Phyllis M; Hoyme, H Eugene

2010-05-01

To examine the variation in significant dysmorphic features in children from 3 different populations with the most dysmorphic forms of fetal alcohol spectrum disorders, fetal alcohol syndrome (FAS), and partial fetal alcohol syndrome (PFAS). Advanced multiple regression techniques are used to determine the discriminating physical features in the diagnosis of FAS and PFAS among children from Northern Plains Indian communities, South Africa, and Italy. Within the range of physical features used to identify children with fetal alcohol spectrum disorders, specifically FAS and PFAS, there is some significant variation in salient diagnostic features from one population to the next. Intraclass correlations in diagnostic features between these 3 populations is 0.20, indicating that about 20% of the variability in dysmorphology core features is associated with location and, therefore, specific racial/ethnic population. The highly significant diagnostic indicators present in each population are identified for the full samples of FAS, PFAS, and normals and also among children with FAS only. A multilevel model for these populations combined indicates that these variables predict dysmorphology unambiguously: small palpebral fissures, narrow vermillion, smooth philtrum, flat nasal bridge, and fifth finger clinodactyly. Long philtrum varies substantially as a predictor in the 3 populations. Predictors not significantly related to fetal alcohol spectrum disorders dysmorphology across the 3 populations are centile of height (except in Italy) strabismus, interpupilary distance, intercanthal distance, and heart murmurs. The dysmorphology associated with FAS and PFAS vary across populations, yet a particular array of common features occurs in each population, which permits a consistent diagnosis across populations.

Titanium Dioxide/Upconversion Nanoparticles/Cadmium Sulfide Nanofibers Enable Enhanced Full-Spectrum Absorption for Superior Solar Light Driven Photocatalysis.

PubMed

Zhang, Fu; Zhang, Chuan-Ling; Wang, Wan-Ni; Cong, Huai-Ping; Qian, Hai-Sheng

2016-06-22

In this work, we demonstrate an electrospinning technique to fabricate TiO2 /upconversion nanoparticles (UCNPs)/CdS nanofibers on large scale. In addition, the as-prepared TiO2 nanofibers are incorporated with a high population of UCNPs and CdS nanospheres; this results in Förster resonance energy-transfer configurations of the UCNPs, TiO2 , and CdS nanospheres that are in close proximity. Hence, strong fluorescent emissions for the Tm(3+) ions including the (1) G4 →(3) H6 transition are efficiently transferred to TiO2 and the CdS nanoparticles through an energy-transfer process. The as-prepared TiO2 /UCNPs/CdS nanofibers exhibit full-spectrum solar-energy absorption and enable the efficient degradation of organic dyes by fluorescence resonance energy transfer between the UCNPs and TiO2 (or CdS). The UCNPs/TiO2 /CdS nanofibers may also have enhanced energy-transfer efficiency for wide applications in solar cells, bioimaging, photodynamics, and chemotherapy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Perturbation analysis of the υ = 6 level in the d3Δ state of CS based on its near-infrared absorption spectrum.

PubMed

Li, Chuanliang; Deng, Lunhua; Zhang, Yan; Wu, Ling; Yang, Xiaohua; Chen, Yangqin

2011-04-14

The spectrum of CS was recorded in the region of 12,086-12,630 cm(-1) by employing optical heterodyne concentration modulation laser absorption spectroscopy. Nearly 350 transitions were assigned to the (6, 0) band in the d(3)Δ-a(3)Π system of CS. The overtone transitions of the (12, 0) band in the a(3)Π(2)-a(3)Π(0) transition were first observed due to the perturbation interaction between d(3)Δ(1) and a(3)Π(2). The Λ doubling in the a(3)Π(1) state was also resolved at high rotational levels. The molecular constants of the a(3)Π (υ = 0) and d(3)Δ (υ = 6) levels and the perturbation parameters of the d(3)Δ (υ = 6) level were determined through nonlinear least-squares fitting using effective hamiltonians. The calculations of mixing fractions of the perturbed states were performed in order to obtain precise information on the perturbations of the d(3)Δ (υ = 6) levels. The mechanisms for perturbations of d(3)Δ (υ = 6) with the a(3)Π (υ = 12) and A(1)Π (υ = 1) levels, especially for the second-order perturbation, were discussed and explained according to first-order nondegenerate perturbation theory.

Experimental study on emission of VOCs from tanker using hollow fiber membrane absorption method with different absorbents

NASA Astrophysics Data System (ADS)

Zhou, J. Y.; Wang, B. F.; Nie, L. H.; Lu, J. X.; Hao, Y. J.; Xu, R. R.

2018-01-01

China’s oil dependence is getting higher and higher, 90% of oil import is transported by sea. Tankers will produce a lot of VOCs during loading and unloading, so the prevention of such pollution has become increasingly urgent. The hollow fiber membrane absorption method combined the characteristics of the absorption method for the treatment of high concentration and large flow of VOCs and the advantage of low energy consumption of membrane method. At present, the research on the recovery of oil and gas is relatively few. In this paper, the effect of membrane absorption on the recovery of oil and gas was investigated. The different absorbent affected the oil vapor recovery, the experimental results showed that the performance of absorbent of AbsFOV-97 was better than that of heat conductive oil.

Electrical potential difference and absorption of water, sodium, and potassium by the terminal ileum of ileostomy patients

PubMed Central

De Moraes-Filho, J. Prado P.; Salas-Coll, C.; Blendis, Laurie; Edmonds, C. J.

1974-01-01

Measurements of electrical potential difference (pd) and of absorption by a dialysis method were carried out in the terminal ileum of patients with an ileostomy. The pd measured with saline in the lumen and at a few centimetres within the stoma averaged 9.2 mV, lumen negatively charged. The pd values were similar whether the ileostomy had been recently or long established. The pd rose considerably when glucose was added to the luminal solution, the maximum effect being attained with a concentration of 40 mmol/1. With a saline bicarbonate solution (Na 145 or 140 m-equiv/1, K 5, or 10 m-equiv/1) in the dialysis tube, considerable absorption of fluid and sodium was demonstrable with little change in sodium concentration. Potassium secretion occurred with the lower, and absorption with the higher, concentration. The final luminal potassium concentration reached was consistent with a passive distribution between blood and lumen. PMID:4448413

A comparison between the observed and predicted Fe II spectrum in different plasmas

NASA Astrophysics Data System (ADS)

Johansson, S.

This paper gives a survey of the spectral distribution of emission lines of Fe II, predicted from a single atomic model. The observed differences between the recorded and the predicted spectrum are discussed in terms of deficiencies of the model and interactions within the emitting plasma. A number of illustrative examples of unexpected features with applications to astrophysics are given. Selective population, due to charge transfer and resonant photo excitation, is elucidated. The future need of more laboratory data for Fe II as regards energy levels and line classification is also discussed.

Differences in praxis performance and receptive language during fingerspelling between deaf children with and without autism spectrum disorder.

PubMed

Bhat, Anjana N; Srinivasan, Sudha M; Woxholdt, Colleen; Shield, Aaron

2018-04-01

Children with autism spectrum disorder present with a variety of social communication deficits such as atypicalities in social gaze and verbal and non-verbal communication delays as well as perceptuo-motor deficits like motor incoordination and dyspraxia. In this study, we had the unique opportunity to study praxis performance in deaf children with and without autism spectrum disorder in a fingerspelling context using American Sign Language. A total of 11 deaf children with autism spectrum disorder and 11 typically developing deaf children aged between 5 and 14 years completed a fingerspelling task. Children were asked to fingerspell 15 different words shown on an iPad. We coded various praxis errors and fingerspelling time. The deaf children with autism spectrum disorder had greater errors in pace, sequence precision, accuracy, and body part use and also took longer to fingerspell each word. Additionally, the deaf children with autism spectrum disorder had poor receptive language skills and this strongly correlated with their praxis performance and autism severity. These findings extend the evidence for dyspraxia in hearing children with autism spectrum disorder to deaf children with autism spectrum disorder. Poor sign language production in children with autism spectrum disorder may contribute to their poor gestural learning/comprehension and vice versa. Our findings have therapeutic implications for children with autism spectrum disorder when teaching sign language.

Studies on different iron source absorption by in situ ligated intestinal loops of broilers.

PubMed

Jia, Y F; Jiang, M M; Sun, J; Shi, R B; Liu, D S

2015-02-01

The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P < 0.05), however, decreased DMT1 and DcytB messenger RNA (mRNA) levels (P < 0.05). Organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)) increased serum iron concentration (SI), compared with inorganic 3 valence iron groups (Fe2(SO4)3 and Fe+Gly(III)) (P < 0.05); moreover, lower TIBC value was observed for the chelate (P < 0.05); however, mixture of inorganic iron and glycine did not have a positive role at DMT1 and DcytB mRNA levels, SI and Fe concentrations in the small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

[Multiple analysis of the difference in intestinal absorption between the main components and the extract of Glycyrrhiza uralensis].

PubMed

Wu, Qing-Qing; Chen, Yan; Xin, Ran; Wang, Jin-Yan; Zhou, Lei; Yuan, Ling; Jia, Xiao-Bin

2012-05-01

The aim of this study is to investigate the rat intestinal absorption behavior of two main active components, liquiritin, glycyrrhizin and the extract of Glycyrrhiza uralensis. The rat intestinal perfusion model was employed. Concentrations of the compounds of the interest in the intestinal perfusate, bile and plasma samples were determined by HPLC and UPLC. At the same time, the intestinal enzymes incubation test and the partition coefficient determination, the absorption of liquiritin and glycyrrhizin alone and the extract were multiple analyzed. The results showed that the P(eff) (effective permeability) of liquiritin or glycyrrhizin alone or the extract was less than 0.3, which suggested their poor absorption in the intestine. The P(eff) of the two main active components or the extract was not significantly different in duodenum, jejunum, colon and ileum segment. The P(eff) of the glycyrrhizin in the extract had no significant difference in the four intestinal segments compared with the glycyrrhizin alone. The absorption of the liquiritin displayed significant difference (P < 0.05) at ileum segment compared with the liquiritin alone, while it had no markedly change in the other three segments. This phenomenon indicated that some ingredients in the extract might improve the absorption of liquiritin. Moreover, no parent compounds and their metabolites were found in the intestinal perfusate, bile and the plasma samples. The results demonstrated that the influence of the other ingredients in the extract on the two components might not increase the amount of liquiritin and glycyrrhizin in the bile and plasma within the duration of the test.

Tunable, high-sensitive measurement of inter-dot transition via tunneling induced absorption

NASA Astrophysics Data System (ADS)

Peng, Yandong; Yang, Aihong; Chen, Bing; Li, Lei; Liu, Shande; Guo, Hongju

2016-10-01

A tunable, narrow absorption spectrum induced by resonant tunneling is demonstrated and proposed for measuring interdot tunneling. Tunneling-induced absorption (TIA) arises from constructive interference between different transition paths, and the large nonlinear TIA significantly enhances the total absorption. The narrow nonlinear TIA spectrum is sensitive to inter-dot tunneling, and its sensor characteristics, including sensitivity and bandwidth, are investigated in weak-coupling and strong-coupling regimes, respectively.

Light Pollution in Ultraviolet and Visible Spectrum: Effect on Different Visual Perceptions

PubMed Central

Solano Lamphar, Héctor Antonio; Kocifaj, Miroslav

2013-01-01

In general terms, lighting research has been focused in the development of artificial light with the purpose of saving energy and having more durable lamps. However, the consequences that artificial night lighting could bring to the human being and living organisms have become an important issue recently. Light pollution represents a significant problem to both the environment and human health causing a disruption of biological rhythms related not only to the visible spectrum, but also to other parts of the electromagnetic spectrum. Since the lamps emit across a wide range of the electromagnetic spectrum, all photobiological species may be exposed to another type of light pollution. By comparing five different lamps, the present study attempts to evaluate UV radiative fluxes relative to what humans and two species of insects perceive as sky glow level. We have analyzed three atmospheric situations: clear sky, overcast sky and evolving precipitable water content. One important finding suggests that when a constant illuminance of urban spaces has to be guaranteed the sky glow from the low pressure sodium lamps has the most significant effect to the visual perception of the insects tested. But having the fixed number of luminaires the situation changes and the low pressure sodium lamp would be the best choice for all three species. The sky glow effects can be interpreted correctly only if the lamp types and the required amount of scotopic luxes at the ground are taken into account simultaneously. If these two factors are combined properly, then the ecological consequences of sky glow can be partly reduced. The results of this research may be equally useful for lighting engineers, architects, biologists and researchers who are studying the effects of sky glow on humans and biodiversity. PMID:23441205

Light pollution in ultraviolet and visible spectrum: effect on different visual perceptions.

PubMed

Solano Lamphar, Héctor Antonio; Kocifaj, Miroslav

2013-01-01

In general terms, lighting research has been focused in the development of artificial light with the purpose of saving energy and having more durable lamps. However, the consequences that artificial night lighting could bring to the human being and living organisms have become an important issue recently. Light pollution represents a significant problem to both the environment and human health causing a disruption of biological rhythms related not only to the visible spectrum, but also to other parts of the electromagnetic spectrum. Since the lamps emit across a wide range of the electromagnetic spectrum, all photobiological species may be exposed to another type of light pollution. By comparing five different lamps, the present study attempts to evaluate UV radiative fluxes relative to what humans and two species of insects perceive as sky glow level. We have analyzed three atmospheric situations: clear sky, overcast sky and evolving precipitable water content. One important finding suggests that when a constant illuminance of urban spaces has to be guaranteed the sky glow from the low pressure sodium lamps has the most significant effect to the visual perception of the insects tested. But having the fixed number of luminaires the situation changes and the low pressure sodium lamp would be the best choice for all three species. The sky glow effects can be interpreted correctly only if the lamp types and the required amount of scotopic luxes at the ground are taken into account simultaneously. If these two factors are combined properly, then the ecological consequences of sky glow can be partly reduced. The results of this research may be equally useful for lighting engineers, architects, biologists and researchers who are studying the effects of sky glow on humans and biodiversity.

How different are the Liège and Hamburg atlases of the solar spectrum?

NASA Astrophysics Data System (ADS)

Doerr, H.-P.; Vitas, N.; Fabbian, D.

2016-05-01

Context. The high-fidelity solar spectral atlas prepared by http://adsabs.harvard.edu/abs/1973apds.book.....D Delbouille et al. (Liège atlas, 1973) and the atlas by http://adsabs.harvard.edu/abs/1999SoPh..184..421N Neckel (Hamburg atlas, 1999, Sol. Phys., 184, 421) are widely recognised as the most important collection of reference spectra of the Sun at disc centre in the visible wavelength range. The two datasets serve as fundamental resources for many researchers, in particular for chemical abundance analyses. But despite their similar published specifications (spectral resolution and noise level), the shapes of the spectral lines in the two atlases differ significantly and systematically. Aims: Knowledge of any instrumental degradations is imperative to fully exploit the information content of spectroscopic data. We seek to investigate the magnitude of these differences and explain the possible sources. We provide the wavelength-dependent correction parameters that need to be taken into account when the spectra are to be compared with synthetic data, for instance. Methods: A parametrically degraded version of the Hamburg spectrum was fitted to the Liège spectrum. The parameters of the model (wavelength shift, broadening, intensity scaling, and intensity offset) represent the different characteristics of the respective instruments, observational strategies, and data processing. Results: The wavelength scales of the Liège and Hamburg atlases differ on average by 0.5 mÅ with a standard deviation of ± 2 mÅ, except for a peculiar region around 5500 Å. The continuum levels are offset by up to 18% below 5000 Å, but remain stably at a 0.8% difference towards the red. We find no evidence for spectral stray light in the Liège spectrum. Its resolving power is almost independent of wavelength but limited to about 216 000, which is between two to six times lower than specified. When accounting for the degradations determined in this work, the spectra of the two

Absorption Profile of (Poly)Phenolic Compounds after Consumption of Three Food Supplements Containing 36 Different Fruits, Vegetables, and Berries

PubMed Central

Bresciani, Letizia; Martini, Daniela; Mena, Pedro; Tassotti, Michele; Calani, Luca; Brigati, Giacomo; Brighenti, Furio; Holasek, Sandra; Malliga, Daniela-Eugenia; Lamprecht, Manfred; Del Rio, Daniele

2017-01-01

The market of plant-based nutraceuticals and food supplements is continuously growing due to the increased consumer demand. The introduction of new products with relevant nutritional characteristics represents a new way of providing bioactive compounds and (poly)phenols to consumers, becoming a strategy to ideally guarantee the health benefits attributed to plant foodstuffs and allowing the increase of daily bioactive compound intake. A paramount step in the study of nutraceuticals is the evaluation of the bioavailability and metabolism of their putatively active components. Therefore, the aim of the present study was to investigate the absorption profile of the (poly)phenolic compounds contained in three different plant-based food supplements, made of 36 different plant matrices, which were consumed by 20 subjects in an open one-arm study design. Blood samples were collected at baseline and 1, 2, 5, and 10 h after capsule intake. Twenty quantifiable metabolites deriving from different (poly)phenolic compounds were identified. Results showed that the consumption of the three capsules allowed the effective absorption of several (poly)phenolic compounds and metabolites appearing at different times in plasma, thereby indicating different absorption profiles. The capsules thus ensured potential health-promoting molecules to be potentially available to target tissues and organs. PMID:28245627

Absorption Profile of (Poly)Phenolic Compounds after Consumption of Three Food Supplements Containing 36 Different Fruits, Vegetables, and Berries.

PubMed

Bresciani, Letizia; Martini, Daniela; Mena, Pedro; Tassotti, Michele; Calani, Luca; Brigati, Giacomo; Brighenti, Furio; Holasek, Sandra; Malliga, Daniela-Eugenia; Lamprecht, Manfred; Del Rio, Daniele

2017-02-26

The market of plant-based nutraceuticals and food supplements is continuously growing due to the increased consumer demand. The introduction of new products with relevant nutritional characteristics represents a new way of providing bioactive compounds and (poly)phenols to consumers, becoming a strategy to ideally guarantee the health benefits attributed to plant foodstuffs and allowing the increase of daily bioactive compound intake. A paramount step in the study of nutraceuticals is the evaluation of the bioavailability and metabolism of their putatively active components. Therefore, the aim of the present study was to investigate the absorption profile of the (poly)phenolic compounds contained in three different plant-based food supplements, made of 36 different plant matrices, which were consumed by 20 subjects in an open one-arm study design. Blood samples were collected at baseline and 1, 2, 5, and 10 h after capsule intake. Twenty quantifiable metabolites deriving from different (poly)phenolic compounds were identified. Results showed that the consumption of the three capsules allowed the effective absorption of several (poly)phenolic compounds and metabolites appearing at different times in plasma, thereby indicating different absorption profiles. The capsules thus ensured potential health-promoting molecules to be potentially available to target tissues and organs.

The moral stereotypes of liberals and conservatives: exaggeration of differences across the political spectrum.

PubMed

Graham, Jesse; Nosek, Brian A; Haidt, Jonathan

2012-01-01

We investigated the moral stereotypes political liberals and conservatives have of themselves and each other. In reality, liberals endorse the individual-focused moral concerns of compassion and fairness more than conservatives do, and conservatives endorse the group-focused moral concerns of ingroup loyalty, respect for authorities and traditions, and physical/spiritual purity more than liberals do. 2,212 U.S. participants filled out the Moral Foundations Questionnaire with their own answers, or as a typical liberal or conservative would answer. Across the political spectrum, moral stereotypes about "typical" liberals and conservatives correctly reflected the direction of actual differences in foundation endorsement but exaggerated the magnitude of these differences. Contrary to common theories of stereotyping, the moral stereotypes were not simple underestimations of the political outgroup's morality. Both liberals and conservatives exaggerated the ideological extremity of moral concerns for the ingroup as well as the outgroup. Liberals were least accurate about both groups.

The Moral Stereotypes of Liberals and Conservatives: Exaggeration of Differences across the Political Spectrum

PubMed Central

Graham, Jesse; Nosek, Brian A.; Haidt, Jonathan

2012-01-01

We investigated the moral stereotypes political liberals and conservatives have of themselves and each other. In reality, liberals endorse the individual-focused moral concerns of compassion and fairness more than conservatives do, and conservatives endorse the group-focused moral concerns of ingroup loyalty, respect for authorities and traditions, and physical/spiritual purity more than liberals do. 2,212 U.S. participants filled out the Moral Foundations Questionnaire with their own answers, or as a typical liberal or conservative would answer. Across the political spectrum, moral stereotypes about “typical” liberals and conservatives correctly reflected the direction of actual differences in foundation endorsement but exaggerated the magnitude of these differences. Contrary to common theories of stereotyping, the moral stereotypes were not simple underestimations of the political outgroup's morality. Both liberals and conservatives exaggerated the ideological extremity of moral concerns for the ingroup as well as the outgroup. Liberals were least accurate about both groups. PMID:23251357

Bartter and Gitelman syndromes: Spectrum of clinical manifestations caused by different mutations

PubMed Central

Al Shibli, Amar; Narchi, Hassib

2015-01-01

Bartter and Gitelman syndromes (BS and GS) are inherited disorders resulting in defects in renal tubular handling of sodium, potassium and chloride. Previously considered as genotypic and phenotypic heterogeneous diseases, recent evidence suggests that they constitute a spectrum of disease caused by different genetic mutations with the molecular defects of chloride reabsorption originating at different sites of the nephron in each condition. Although they share some characteristic metabolic abnormalities such as hypokalemia, metabolic alkalosis, hyperplasia of the juxtaglomerular apparatus with hyperreninemia, hyperaldosteronism, the clinical and laboratory manifestations may not always allow distinction between them. Diuretics tests, measuring the changes in urinary fractional excretion of chloride from baseline after administration of either hydrochlorothiazide or furosemide show very little change (< 2.3%) in the fractional excretion of chloride from baseline in GS when compared with BS, except when BS is associated with KCNJ1 mutations where a good response to both diuretics exists. The diuretic test is not recommended for infants or young children with suspected BS because of a higher risk of volume depletion in such children. Clinical symptoms and biochemical markers of GS and classic form of BS (type III) may overlap and thus genetic analysis may specify the real cause of symptoms. However, although genetic analysis is available, its use remains limited because of limited availability, large gene dimensions, lack of hot-spot mutations, heavy workup time and costs involved. Furthermore, considerable overlap exists between the different genotypes and phenotypes. Although BS and GS usually have distinct presentations and are associated with specific gene mutations, there remains considerable overlap between their phenotypes and genotypes. Thus, they are better described as a spectrum of clinical manifestations caused by different gene mutations. PMID:26140272

Absorption of a linear (L2) and a cyclic (D4) siloxane using different oils: application to biogas treatment.

PubMed

Rojas Devia, Carolina; Subrenat, Albert

2013-01-01

Hydrophobic volatile methyl siloxanes (VMS), such as hexamethyldisiloxane (L2) and octamethylcyclotetrasiloxane (D4), present a low solubility in water. An alternative treatment by absorption into hydrophobic absorbents was therefore studied. For this purpose, three different absorbents, motor oil, cutting oil and a water-cutting oil mixture, were selected with the aim of re-using a waste product. The set of experiments was carried out in a bubble column, where parameters such as inlet concentration, residence time and temperature were studied. The best performance for the removal of both siloxanes, in terms of absorption capacity, was observed for motor oil, particularly for D4. In fact, motor oil removal efficiency for D 4 was 80%, whereas for L2 it was 60%, indicating that D 4 is more easily absorbed than L2. In the case of water-cutting oil, this showed a mass transfer enhancement from the gas phase to the liquid phase compared with water alone. Furthermore, a removal efficiency of 70% was observed for D 4, showing that the addition of an oil fraction to a water system improves the absorption of VMS. These results show that VMS absorption into oils could be a promising way to achieve their abatement.

Geant4 simulations of the absorption of photons in CsI and NaI produced by electrons with energies up to 4 MeV and their application to precision measurements of the β-energy spectrum with a calorimetric technique

NASA Astrophysics Data System (ADS)

Huyan, X.; Naviliat-Cuncic, O.; Voytas, P.; Chandavar, S.; Hughes, M.; Minamisono, K.; Paulauskas, S. V.

2018-01-01

The yield of photons produced by electrons slowing down in CsI and NaI was studied with four electromagnetic physics constructors included in the Geant4 toolkit. The subsequent absorption of photons in detector geometries used for measurements of the β spectrum shape was also studied with a focus on the determination of the absorption fraction. For electrons with energies in the range 0.5-4 MeV, the relative photon yields determined with the four Geant4 constructors differ at the level of 10-2 in amplitude and the relative absorption fractions differ at the level of 10-4 in amplitude. The differences among constructors enabled the estimation of the sensitivity to Geant4 simulations for the measurement of the β energy spectrum shape in 6He decay using a calorimetric technique with ions implanted in the active volume of detectors. The size of the effect associated with photons escaping the detectors was quantified in terms of a slope which, on average, is respectively - 5 . 4 %/MeV and - 4 . 8 %/MeV for the CsI and NaI geometries. The corresponding relative uncertainties as determined from the spread of results obtained with the four Geant4 constructors are 0.0067 and 0.0058.

Novel ratio difference at coabsorptive point spectrophotometric method for determination of components with wide variation in their absorptivities.

PubMed

Saad, Ahmed S; Abo-Talib, Nisreen F; El-Ghobashy, Mohamed R

2016-01-05

Different methods have been introduced to enhance selectivity of UV-spectrophotometry thus enabling accurate determination of co-formulated components, however mixtures whose components exhibit wide variation in absorptivities has been an obstacle against application of UV-spectrophotometry. The developed ratio difference at coabsorptive point method (RDC) represents a simple effective solution for the mentioned problem, where the additive property of light absorbance enabled the consideration of the two components as multiples of the lower absorptivity component at certain wavelength (coabsorptive point), at which their total concentration multiples could be determined, whereas the other component was selectively determined by applying the ratio difference method in a single step. Mixture of perindopril arginine (PA) and amlodipine besylate (AM) figures that problem, where the low absorptivity of PA relative to AM hinders selective spectrophotometric determination of PA. The developed method successfully determined both components in the overlapped region of their spectra with accuracy 99.39±1.60 and 100.51±1.21, for PA and AM, respectively. The method was validated as per the USP guidelines and showed no significant difference upon statistical comparison with reported chromatographic method. Copyright © 2015 Elsevier B.V. All rights reserved.

Sources of group differences in functional connectivity: an investigation applied to autism spectrum disorder.

PubMed

Jones, Tyler B; Bandettini, Peter A; Kenworthy, Lauren; Case, Laura K; Milleville, Shawn C; Martin, Alex; Birn, Rasmus M

2010-01-01

An increasing number of fMRI studies are using the correlation of low-frequency fluctuations between brain regions, believed to reflect synchronized variations in neuronal activity, to infer "functional connectivity". In studies of autism spectrum disorder (ASD), decreases in this measure of connectivity have been found by focusing on the response to task modulation, by using only the rest periods, or by analyzing purely resting-state data. This difference in connectivity, however, could result from a number of different mechanisms--differences in noise, task-related fluctuations, task performance, or spontaneous neuronal activity. In this study, we investigate the difference in functional connectivity between adolescents with high-functioning ASD and typically developing control subjects by examining the residual fluctuations occurring on top of the fMRI response to an overt verbal fluency task. We find decreased correlations of these residuals (a decreased "connectivity") in ASD subjects. Furthermore, we find that this decrease was not due to task-related effects, block-to-block variations in task performance, or increased noise, and the difference was greatest when primarily rest periods are considered. These findings suggest that the estimate of disrupted functional connectivity in ASD is likely driven by differences in task-unrelated neuronal fluctuations.

Comparison of absorption properties of colored dissolved organic matter in six different case 2 water bodies

NASA Astrophysics Data System (ADS)

Nima, Ciren; Frette, Øyvind; Hamre, Børge; Erga, Svein Rune; Chen, Yi-Chun; Zhao, Lu; Muyimbwa, Dennis; Ssenyonga, Taddeo; Ssebiyonga, Nicolausi; Okullo, Willy; Stamnes, Knut; Stamnes, Jakob J.

2017-02-01

Colored Dissolved Organic Matter (CDOM) is one of the main factors controlling the penetration of solar radiation in Case 2 water and affecting satellite-based estimation of ocean color. We present absorption properties of CDOM sampled in 6 water bodies including three in Norway (Røst coastal water, Samnangerfjord, Lysefjord), two in China (Bohai Sea, Lake Namtso), and one in Africa (Lake Victoria). These locations, which range from near the equator to subarctic regions, include water types from oligotrophic to eutrophic, and altitudes from sea level to 4,700 m above sea level.

Infrared absorption band in deformed qtz crystals analyzed by combining different microstructural methods

NASA Astrophysics Data System (ADS)

Stunitz, Holger; Thust, Anja; Behrens, Harald; Heilbronner, Renee; Kilian, Ruediger

2016-04-01

Natural single crystals of quartz have been experimentally deformed in two orientations: (1) normal to one prism-plane, (2) In O+ orientation at temperatures of 900 and 1000°C, pressures of 1.0 and 1.5 GPa, and strain rates of ~1 x 10-6s-1. The starting material is milky quartz, consisting of dry quartz (H2O contents of <150 H/106Si) with fluid inclusions (FI). During pressurization many FÍs decrepitate. Cracks heal and small neonate FÍs form, increasing the number of FÍs drastically. During subsequent deformation, the size of FÍs is further reduced (down to ~10 nm). Sample deformation occurs by dominant dislocation glide on selected slip systems, accompanied by some dynamic recovery. Strongly deformed regions show FTIR spectra with a pointed broad absorption band in the ~3400 cm-1 region as a superposition of molecular H2O bands and three discrete absorption bands (at 3367, 3400, and 3434 cm-1). In addition, there is a discrete absorption band at 3585 cm-1, which only occurs in deformed regions. The 3585 cm-1 band is reduced or even disappears after annealing. This band is polarized and represents structurally bound H, its H-content is estimated to be 1-3% of the total H2O-content and appears to be associated with dislocations. The H2O weakening effect in our FI-bearing natural quartz crystals is assigned to the processes of dislocation generation and multiplication at small FÍs. The deformation processes in these crystals represent a recycling of H2O between FÍs, dislocation generation at very small fluid inclusions, incorporation of structurally bound H into dislocation cores, and release of H2O from dislocations back into FÍs during recovery. Cracking and crack healing play an important role in the recycling process and imply a close interrelationship between brittle and crystal plastic deformation. The H2O weakening by this process is of a disequilibrium nature and thus depends on the amount of H2O available.

Validation of phenol red versus gravimetric method for water reabsorption correction and study of gender differences in Doluisio's absorption technique.

PubMed

Tuğcu-Demiröz, Fatmanur; Gonzalez-Alvarez, Isabel; Gonzalez-Alvarez, Marta; Bermejo, Marival

2014-10-01

The aim of the present study was to develop a method for water flux reabsorption measurement in Doluisio's Perfusion Technique based on the use of phenol red as a non-absorbable marker and to validate it by comparison with gravimetric procedure. The compounds selected for the study were metoprolol, atenolol, cimetidine and cefadroxil in order to include low, intermediate and high permeability drugs absorbed by passive diffusion and by carrier mediated mechanism. The intestinal permeabilities (Peff) of the drugs were obtained in male and female Wistar rats and calculated using both methods of water flux correction. The absorption rate coefficients of all the assayed compounds did not show statistically significant differences between male and female rats consequently all the individual values were combined to compare between reabsorption methods. The absorption rate coefficients and permeability values did not show statistically significant differences between the two strategies of concentration correction. The apparent zero order water absorption coefficients were also similar in both correction procedures. In conclusion gravimetric and phenol red method for water reabsorption correction are accurate and interchangeable for permeability estimation in closed loop perfusion method. Copyright © 2014 Elsevier B.V. All rights reserved.

Mineral absorption by albino rats as affected by some types of dietary pectins with different degrees of esterification.

PubMed

el-Zoghbi, M; Sitohy, M Z

2001-04-01

Male albino rats were fed diets contained 6.85% mineral salts for 2 weeks (adaptation condition). Then they were fed the dietary pectin administered diet for 6 weeks to evaluate the effect of administration of pectin on the absorption of some monovalent, bivalent and heavy metals in the serum of rats. The experimental parameters included, monovalent minerals (K, Na), bivalent minerals (Zn, Cu, Ca, Fe), heavy metals (Pb, Cd), serum uric acid and serum creatinine. The obtained results indicated that the serum contents of monovalent minerals were negatively affected by pectin administration. The low degree of esterification of pectin was more effective on the absorption of bivalent minerals. Also, the rat serum levels of lead and cadmium were reduced by pectin administration. Serum total proteins were reduced by pectin administration. The level of rat serum of uric acid and creatinine fed different sources of pectin were within normal levels and were insignificantly lower than that recorded for control samples.

Differences in neural activity when processing emotional arousal and valence in autism spectrum disorders.

PubMed

Tseng, Angela; Wang, Zhishun; Huo, Yuankai; Goh, Suzanne; Russell, James A; Peterson, Bradley S

2016-02-01

Individuals with autism spectrum disorders (ASD) often have difficulty recognizing and interpreting facial expressions of emotion, which may impair their ability to navigate and communicate successfully in their social, interpersonal environments. Characterizing specific differences between individuals with ASD and their typically developing (TD) counterparts in the neural activity subserving their experience of emotional faces may provide distinct targets for ASD interventions. Thus we used functional magnetic resonance imaging (fMRI) and a parametric experimental design to identify brain regions in which neural activity correlated with ratings of arousal and valence for a broad range of emotional faces. Participants (51 ASD, 84 TD) were group-matched by age, sex, IQ, race, and socioeconomic status. Using task-related change in blood-oxygen-level-dependent (BOLD) fMRI signal as a measure, and covarying for age, sex, FSIQ, and ADOS scores, we detected significant differences across diagnostic groups in the neural activity subserving the dimension of arousal but not valence. BOLD-signal in TD participants correlated inversely with ratings of arousal in regions associated primarily with attentional functions, whereas BOLD-signal in ASD participants correlated positively with arousal ratings in regions commonly associated with impulse control and default-mode activity. Only minor differences were detected between groups in the BOLD signal correlates of valence ratings. Our findings provide unique insight into the emotional experiences of individuals with ASD. Although behavioral responses to face-stimuli were comparable across diagnostic groups, the corresponding neural activity for our ASD and TD groups differed dramatically. The near absence of group differences for valence correlates and the presence of strong group differences for arousal correlates suggest that individuals with ASD are not atypical in all aspects of emotion-processing. Studying these similarities

Differences in Neural Activity when Processing Emotional Arousal and Valence in Autism Spectrum Disorders

PubMed Central

Tseng, Angela; Wang, Zhishun; Huo, Yuankai; Goh, Suzanne; Russell, James A.; Peterson, Bradley S.

2016-01-01

Individuals with autism spectrum disorders (ASD) often have difficulty recognizing and interpreting facial expressions of emotion, which may impair their ability to navigate and communicate successfully in their social, interpersonal environments. Characterizing specific differences between individuals with ASD and their typically-developing (TD) counterparts in the neural activity subserving their experience of emotional faces may provide distinct targets for ASD interventions. Thus we used functional magnetic resonance imaging (fMRI) and a parametric experimental design to identify brain regions in which neural activity correlated with ratings of arousal and valence for a broad range of emotional faces. Participants (51 ASD, 84 TD) were group-matched by age, sex, IQ, race, and socioeconomic status. Using task-related change in blood-oxygen-level-dependent (BOLD) fMRI signal as a measure, and covarying for age, sex, FSIQ, and ADOS scores, we detected significant differences across diagnostic groups in the neural activity subserving the dimension of arousal but not valence. BOLD-signal in TD participants correlated inversely with ratings of arousal in regions associated primarily with attentional functions, whereas BOLD-signal in ASD participants correlated positively with arousal ratings in regions commonly associated with impulse control and default-mode activity. Only minor differences were detected between groups in the BOLD signal correlates of valence ratings. Our findings provide unique insight into the emotional experiences of individuals with ASD. Although behavioral responses to face-stimuli were comparable across diagnostic groups, the corresponding neural activity for our ASD and TD groups differed dramatically. The near absence of group differences for valence correlates and the presence of strong group differences for arousal correlates suggest that individuals with ASD are not atypical in all aspects of emotion-processing. Studying these similarities

Novel absorptivity centering method utilizing normalized and factorized spectra for analysis of mixtures with overlapping spectra in different matrices using built-in spectrophotometer software

NASA Astrophysics Data System (ADS)

Lotfy, Hayam Mahmoud; Omran, Yasmin Rostom

2018-07-01

A novel, simple, rapid, accurate, and economical spectrophotometric method, namely absorptivity centering (a-Centering) has been developed and validated for the simultaneous determination of mixtures with partially and completely overlapping spectra in different matrices using either normalized or factorized spectrum using built-in spectrophotometer software without a need of special purchased program. Mixture I (Mix I) composed of Simvastatin (SM) and Ezetimibe (EZ) is the one with partial overlapping spectra formulated as tablets, while mixture II (Mix II) formed by Chloramphenicol (CPL) and Prednisolone acetate (PA) is that with complete overlapping spectra formulated as eye drops. These procedures do not require any separation steps. Resolution of spectrally overlapping binary mixtures has been achieved getting recovered zero-order (D0) spectrum of each drug, then absorbance was recorded at their maxima 238, 233.5, 273 and 242.5 nm for SM, EZ, CPL and PA, respectively. Calibration graphs were established with good correlation coefficients. The method shows significant advantages as simplicity, minimal data manipulation besides maximum reproducibility and robustness. Moreover, it was validated according to ICH guidelines. Selectivity was tested using laboratory-prepared mixtures. Accuracy, precision and repeatability were found to be within the acceptable limits. The proposed method is good enough to be applied to an assay of drugs in their combined formulations without any interference from excipients. The obtained results were statistically compared with those of the reported and official methods by applying t-test and F-test at 95% confidence level concluding that there is no significant difference with regard to accuracy and precision. Generally, this method could be used successfully for the routine quality control testing.

Novel absorptivity centering method utilizing normalized and factorized spectra for analysis of mixtures with overlapping spectra in different matrices using built-in spectrophotometer software.

PubMed

Lotfy, Hayam Mahmoud; Omran, Yasmin Rostom

2018-07-05

A novel, simple, rapid, accurate, and economical spectrophotometric method, namely absorptivity centering (a-Centering) has been developed and validated for the simultaneous determination of mixtures with partially and completely overlapping spectra in different matrices using either normalized or factorized spectrum using built-in spectrophotometer software without a need of special purchased program. Mixture I (Mix I) composed of Simvastatin (SM) and Ezetimibe (EZ) is the one with partial overlapping spectra formulated as tablets, while mixture II (Mix II) formed by Chloramphenicol (CPL) and Prednisolone acetate (PA) is that with complete overlapping spectra formulated as eye drops. These procedures do not require any separation steps. Resolution of spectrally overlapping binary mixtures has been achieved getting recovered zero-order (D 0 ) spectrum of each drug, then absorbance was recorded at their maxima 238, 233.5, 273 and 242.5 nm for SM, EZ, CPL and PA, respectively. Calibration graphs were established with good correlation coefficients. The method shows significant advantages as simplicity, minimal data manipulation besides maximum reproducibility and robustness. Moreover, it was validated according to ICH guidelines. Selectivity was tested using laboratory-prepared mixtures. Accuracy, precision and repeatability were found to be within the acceptable limits. The proposed method is good enough to be applied to an assay of drugs in their combined formulations without any interference from excipients. The obtained results were statistically compared with those of the reported and official methods by applying t-test and F-test at 95% confidence level concluding that there is no significant difference with regard to accuracy and precision. Generally, this method could be used successfully for the routine quality control testing. Copyright © 2018 Elsevier B.V. All rights reserved.

Generativity and imagination in autism spectrum disorder: evidence from individual differences in children's impossible entity drawings.

PubMed

Low, Jason; Goddard, Elizabeth; Melser, Joseph

2009-06-01

This study examined the cognitive underpinnings of spontaneous imagination in autism spectrum disorder (ASD) by way of individual differences. Children with ASD (N = 27) and matched typically developing (TD) children were administered Karmiloff-Smith's (1990) imaginative drawing task, along with measures that tapped specific executive functions (generativity, visuospatial planning, and central coherence processing style) and false belief theory of mind (ToM) understanding. The ASD group drawings displayed deficits in imaginative content and a piecemeal pictorial style. ASD participants also showed group deficits in generativity, planning and ToM, and exhibited weak coherence. Individual differences in generativity were related to imaginative drawing content in the ASD group, and the association was mediated through planning ability. Variations in weak coherence were separately related to a piecemeal drawing style in the ASD group. Variations in generativity were also linked with imaginative drawing content in the TD group; the connection unfolded when it received pooled variance from receptive language ability, and thereupon mediated through false belief reasoning to cue imaginative content. Results are discussed in terms of how generativity plays a broad and important role for imagination in ASD and typical development, albeit in different ways.

The impacts of different expansion modes on performance of small solar energy firms: perspectives of absorptive capacity.

PubMed

Chen, Hsing Hung; Shen, Tao; Xu, Xin-Long; Ma, Chao

2013-01-01

The characteristics of firm's expansion by differentiated products and diversified products are quite different. However, the study employing absorptive capacity to examine the impacts of different modes of expansion on performance of small solar energy firms has never been discussed before. Then, a conceptual model to analyze the tension between strategies and corporate performance is proposed to filling the vacancy. After practical investigation, the results show that stronger organizational institutions help small solar energy firms expanded by differentiated products increase consistency between strategies and corporate performance; oppositely, stronger working attitudes with weak management controls help small solar energy firms expanded by diversified products reduce variance between strategies and corporate performance.

The Impacts of Different Expansion Modes on Performance of Small Solar Energy Firms: Perspectives of Absorptive Capacity

PubMed Central

Chen, Hsing Hung; Shen, Tao; Xu, Xin-long; Ma, Chao

2013-01-01

The characteristics of firm's expansion by differentiated products and diversified products are quite different. However, the study employing absorptive capacity to examine the impacts of different modes of expansion on performance of small solar energy firms has never been discussed before. Then, a conceptual model to analyze the tension between strategies and corporate performance is proposed to filling the vacancy. After practical investigation, the results show that stronger organizational institutions help small solar energy firms expanded by differentiated products increase consistency between strategies and corporate performance; oppositely, stronger working attitudes with weak management controls help small solar energy firms expanded by diversified products reduce variance between strategies and corporate performance. PMID:24453837

A Spectrum Pedagogy for Christian Ethics: Respecting Difference without Resorting to Relativism

ERIC Educational Resources Information Center

Heim, Joel J.; Scovill, Nelia Beth

2010-01-01

This paper presents an overview of a newly developed spectrum pedagogy of Christian ethics that emerged from the authors' experience of teaching a contemporary Christian ethics course for seven years. A spectrum pedagogy is a comprehensive approach to teaching Christian ethics that combines the modeling of key dispositions using specific tools…

Sex Differences in Pre-Diagnosis Concerns for Children Later Diagnosed with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Hiller, Rachel M.; Young, Robyn L.; Weber, Nathan

2016-01-01

In the absence of intellectual impairment, girls are diagnosed with autism spectrum disorder significantly less and later than boys. This study explored potential reasons for why autism spectrum disorder may be more difficult to identify in girls, based on carer concerns during the pre-diagnosis period. Carers of 92 boys and 60 girls diagnosed…

Understanding Differences in Neurotypical and Autism Spectrum Special Interests through Internet Forums

ERIC Educational Resources Information Center

Jordan, Chloe Jennifer; Caldwell-Harris, Catherine L.

2012-01-01

Special interests are frequently developed by individuals with autism spectrum disorder, expressed as an intense focus on specific topics. Neurotypical individuals also develop special interests, often in the form of hobbies. Although past research has focused on special interests held by children with autism spectrum disorder, little is known…

False Belief Reasoning in Adults with and without Autistic Spectrum Disorder: Similarities and Differences.

PubMed

Sommer, Monika; Döhnel, Katrin; Jarvers, Irina; Blaas, Lore; Singer, Manuela; Nöth, Victoria; Schuwerk, Tobias; Rupprecht, Rainer

2018-01-01

A central diagnostic criteria for autism spectrum disorder (ASD) is the qualitative impairment in reciprocal social interaction and a prominent hypotheses that tried to explain this impairment is the Theory of Mind (ToM) deficit hypotheses. On a behavioral level the critical test for having a ToM, the understanding of false beliefs (FB), is often used for testing ToM abilities in individuals with ASD. Investigating the neural underpinnings several neuroimaging studies revealed a network of areas involved in FB reasoning in neurotypical individuals. For ASD individuals the neural correlates of false belief processing are largely unknown. Using functional magnetic resonance imaging and an adapted unexpected transfer task, that makes it possible to distinguish between the computation of diverging beliefs and the selection of a belief-associated response, we investigated a group of adult high-functioning individuals with ASD ( N = 15) and an age and IQ matched group of neurotypical adults (NT; N = 15). On the behavioral level we found no group differences. On the neural level, results were two-fold: In the story phase, in which participants had to compute whether the character's belief is congruent or incongruent to their own belief, there were no differences between neurotypical participants and those diagnosed with ASD. But, in the subsequent question phase, participants with ASD showed increased activity in the bilateral anterior prefrontal cortex, the left posterior frontal cortex, the left superior temporal gyrus, and the left temporoparietal area. These results suggest that during the story phase in which the participants processed observable actions the neural correlates do not differ between adult individuals with ASD and NT individuals. But in the question phase in which participants had to infer an unobservable mental state results revealed neural differences between the two groups. Possibly, these subtle neural processing differences may contribute to the

False Belief Reasoning in Adults with and without Autistic Spectrum Disorder: Similarities and Differences

PubMed Central

Sommer, Monika; Döhnel, Katrin; Jarvers, Irina; Blaas, Lore; Singer, Manuela; Nöth, Victoria; Schuwerk, Tobias; Rupprecht, Rainer

2018-01-01

A central diagnostic criteria for autism spectrum disorder (ASD) is the qualitative impairment in reciprocal social interaction and a prominent hypotheses that tried to explain this impairment is the Theory of Mind (ToM) deficit hypotheses. On a behavioral level the critical test for having a ToM, the understanding of false beliefs (FB), is often used for testing ToM abilities in individuals with ASD. Investigating the neural underpinnings several neuroimaging studies revealed a network of areas involved in FB reasoning in neurotypical individuals. For ASD individuals the neural correlates of false belief processing are largely unknown. Using functional magnetic resonance imaging and an adapted unexpected transfer task, that makes it possible to distinguish between the computation of diverging beliefs and the selection of a belief-associated response, we investigated a group of adult high-functioning individuals with ASD (N = 15) and an age and IQ matched group of neurotypical adults (NT; N = 15). On the behavioral level we found no group differences. On the neural level, results were two-fold: In the story phase, in which participants had to compute whether the character's belief is congruent or incongruent to their own belief, there were no differences between neurotypical participants and those diagnosed with ASD. But, in the subsequent question phase, participants with ASD showed increased activity in the bilateral anterior prefrontal cortex, the left posterior frontal cortex, the left superior temporal gyrus, and the left temporoparietal area. These results suggest that during the story phase in which the participants processed observable actions the neural correlates do not differ between adult individuals with ASD and NT individuals. But in the question phase in which participants had to infer an unobservable mental state results revealed neural differences between the two groups. Possibly, these subtle neural processing differences may contribute to the

Sex differences in frontal lobe connectivity in adults with autism spectrum conditions.

PubMed

Zeestraten, E A; Gudbrandsen, M C; Daly, E; de Schotten, M T; Catani, M; Dell'Acqua, F; Lai, M-C; Ruigrok, A N V; Lombardo, M V; Chakrabarti, B; Baron-Cohen, S; Ecker, C; Murphy, D G M; Craig, M C

2017-04-11

Autism spectrum conditions (ASC) are more prevalent in males than females. The biological basis of this difference remains unclear. It has been postulated that one of the primary causes of ASC is a partial disconnection of the frontal lobe from higher-order association areas during development (that is, a frontal 'disconnection syndrome'). Therefore, in the current study we investigated whether frontal connectivity differs between males and females with ASC. We recruited 98 adults with a confirmed high-functioning ASC diagnosis (61 males: aged 18-41 years; 37 females: aged 18-37 years) and 115 neurotypical controls (61 males: aged 18-45 years; 54 females: aged 18-52 years). Current ASC symptoms were evaluated using the Autism Diagnostic Observation Schedule (ADOS). Diffusion tensor imaging was performed and fractional anisotropy (FA) maps were created. Mean FA values were determined for five frontal fiber bundles and two non-frontal fiber tracts. Between-group differences in mean tract FA, as well as sex-by-diagnosis interactions were assessed. Additional analyses including ADOS scores informed us on the influence of current ASC symptom severity on frontal connectivity. We found that males with ASC had higher scores of current symptom severity than females, and had significantly lower mean FA values for all but one tract compared to controls. No differences were found between females with or without ASC. Significant sex-by-diagnosis effects were limited to the frontal tracts. Taking current ASC symptom severity scores into account did not alter the findings, although the observed power for these analyses varied. We suggest these findings of frontal connectivity abnormalities in males with ASC, but not in females with ASC, have the potential to inform us on some of the sex differences reported in the behavioral phenotype of ASC.

Neuropsychological Impairments and Age-Related Differences in Children and Adolescents with Fetal Alcohol Spectrum Disorders.

PubMed

Tamana, Sukhpreet; Pei, Jacqueline; Massey, Donald; Massey, Valerie; Rasmussen, Carmen

2014-01-01

BackgroundChildren and adolescents with Fetal Alcohol Spectrum Disorders (FASD) exhibit a range of physical, cognitive, behavioral, and/or learning deficits, as wells as poor executive functioning (EF). Children and adolescents with FASD often show greater impairments on complex neuropsychological tasks. However, little is known about age-related differences among children and adolescents with FASD.ObjectivesThe goals of this cross-sectional study were to explore the overall profile of neuropsychological impairments and extended previous reports on age-related differences among children and adolescents with FASD. MethodWe compared 117 children and adolescents diagnosed with an FASD (aged 5-17 years), clinically assessed on a broad range of tests covering 6 neurobehavioral domains. Data from a clinical database was used to generate profiles of neuropsychological impairments for clinically referred children and adolescents evaluated for FASD between 2001 and 2005. ResultsChildren and adolescents were impaired (relative to the norm) on a number of domains that include academic achievement, language, verbal memory, EF, visual-motor integration, and motor abilities. Older participants with FASD (relative to the norm) showed greater difficulty in areas involving EF or processing of complex information than younger participants. ConclusionsThese results suggest that for children and adolescents with FASD impairments in those areas important for independent functioning may become more pronounced with increasing age. However, further longitudinal research is needed to ascertain age changes over time.

Children with Autism Spectrum Disorder scan own-race faces differently from other-race faces.

PubMed

Yi, Li; Quinn, Paul C; Fan, Yuebo; Huang, Dan; Feng, Cong; Joseph, Lisa; Li, Jiao; Lee, Kang

2016-01-01

It has been well documented that people recognize and scan other-race faces differently from faces of their own race. The current study examined whether this cross-racial difference in face processing found in the typical population also exists in individuals with Autism Spectrum Disorder (ASD). Participants included 5- to 10-year-old children with ASD (n=29), typically developing (TD) children matched on chronological age (n=29), and TD children matched on nonverbal IQ (n=29). Children completed a face recognition task in which they were asked to memorize and recognize both own- and other-race faces while their eye movements were tracked. We found no recognition advantage for own-race faces relative to other-race faces in any of the three groups. However, eye-tracking results indicated that, similar to TD children, children with ASD exhibited a cross-racial face-scanning pattern: they looked at the eyes of other-race faces longer than at those of own-race faces, whereas they looked at the mouth of own-race faces longer than at that of other-race faces. The findings suggest that although children with ASD have difficulty with processing some aspects of faces, their ability to process face race information is relatively spared. Copyright © 2015 Elsevier Inc. All rights reserved.

Examination of Sex Differences in a Large Sample of Young Children with Autism Spectrum Disorder and Typical Development

ERIC Educational Resources Information Center

Reinhardt, Vanessa P.; Wetherby, Amy M.; Schatschneider, Christopher; Lord, Catherine

2015-01-01

Despite consistent and substantive research documenting a large male to female ratio in Autism Spectrum Disorder (ASD), only a modest body of research exists examining sex differences in characteristics. This study examined sex differences in developmental functioning and early social communication in children with ASD as compared to children with…

Sex Differences in Children with Autism Spectrum Disorders Compared with Their Unaffected Siblings and Typically Developing Children

ERIC Educational Resources Information Center

Park, Subin; Cho, Soo-Churl; Cho, In Hee; Kim, Boong-Nyun; Kim, Jae-Won; Shin, Min-Sup; Chung, Un-Sun; Park, Tae-Won; Son, Jung-Woo; Yoo, Hee Jeong

2012-01-01

This study examined the nature of cognitive and behavioral sex differences in children with autism spectrum disorders (ASDs) and two comparison groups: a group of typically developing (TD) children and a group of unaffected siblings of ASD children. Sex differences in core autistic symptoms, co-occurring behavioral symptoms, and cognitive styles…

Age-related differences in cognition across the adult lifespan in autism spectrum disorder.

PubMed

Lever, Anne G; Geurts, Hilde M

2016-06-01

It is largely unknown how age impacts cognition in autism spectrum disorder (ASD). We investigated whether age-related cognitive differences are similar, reduced or increased across the adult lifespan, examined cognitive strengths and weaknesses, and explored whether objective test performance is related to subjective cognitive challenges. Neuropsychological tests assessing visual and verbal memory, generativity, and theory of mind (ToM), and a self-report measure assessing cognitive failures were administered to 236 matched participants with and without ASD, aged 20-79 years (IQ > 80). Group comparisons revealed that individuals with ASD had higher scores on visual memory, lower scores on generativity and ToM, and similar performance on verbal memory. However, ToM impairments were no longer present in older (50+ years) adults with ASD. Across adulthood, individuals with ASD demonstrated similar age-related effects on verbal memory, generativity, and ToM, while age-related differences were reduced on visual memory. Although adults with ASD reported many cognitive failures, those were not associated with neuropsychological test performance. Hence, while some cognitive abilities (visual and verbal memory) and difficulties (generativity and semantic memory) persist across adulthood in ASD, others become less apparent in old age (ToM). Age-related differences characteristic of typical aging are reduced or parallel, but not increased in individuals with ASD, suggesting that ASD may partially protect against an age-related decrease in cognitive functioning. Despite these findings, adults with ASD experience many cognitive daily challenges, which highlights the need for adequate social support and the importance of further research into this topic, including longitudinal studies. Autism Res 2016, 9: 666-676. © 2015 International Society for Autism Research, Wiley Periodicals, Inc. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Social skills: differences among adults with intellectual disabilities, co-morbid autism spectrum disorders and epilepsy.

PubMed

Smith, Kimberly R M; Matson, Johnny L

2010-01-01

Assessing social skills is one of the most complex and challenging areas to study because behavioral repertoires vary depending on an individual's culture and context. However, researchers have conclusively demonstrated that individuals with intellectual disabilities (ID) have impaired social skills as well as those with co-morbid autism spectrum disorders (ASD) and epilepsy. However, it is unknown how these groups differ. Assessment of social skills was made with the Matson Evaluation of Social Skills for Individuals with Severe Retardation. One hundred participants with ID were matched and compared across four equal groups comprising 25 participants with ID, 25 participants with epilepsy, 25 participants with ASD, and 25 participants with combined ASD and epilepsy. When controlling for age, gender, race, level of ID, and hearing and visual impairments, significant differences were found among the four groups on the MESSIER, Wilks's Λ=.58, F(18, 257)=3.05, p<.01. The multivariate η(2) based on Wilks's Λ was .17. Significant differences were found on the Positive Verbal subscale, F(3, 96)=3.70, p<.01, η(2)=.10, Positive Non-verbal subscale, F(3, 96)=8.95, p<.01, η(2)=.22, General Positive subscale, F(3, 96)=7.30, p<.01, η(2)=.19, Negative Non-verbal subscale, F(3, 96)=5.30, p<.01, η(2)=.14, and General Negative subscale, F(3, 96)=3.16, p<.05, η(2)=.09. Based on these results, individuals with ID expressing combined co-morbid ASD and epilepsy had significantly more impaired social skills than the ID only or groups containing only a single co-morbid factor with ID (ASD or epilepsy only). Implications of these findings are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Using ultraviolet-visible ( UV-Vis) absorption spectrum to estimate the dissolved organic matter (DOM) concentration in water, soils and sediments of typical water-level fluctuation zones of the Three Gorges Reservoir areas].

PubMed

Li, Lu-lu; Jiang, Tao; Lu, Song; Yan, Jin-long; Gao, Jie; Wei, Shi-qiang; Wang, Ding-yong; Guo, Nian; Zhao, Zhena

2014-09-01

Dissolved organic matter (DOM) is a very important component in terrestrial ecosystem. Chromophoric dissolved organic matter (CDOM) is a significant constituent of DOM, which can be measured by ultraviolet-visible (UV-Vis) absorption spectrum. Thus the relationship between CDOM and DOM was investigated and established by several types of models including single-wavelength model, double-wavelength model, absorption spectrum slope (S value) model and three-wavelength model, based on the UV-Vis absorption coefficients of soil and sediment samples (sampled in July of 2012) and water samples (sampled in November of 2012) respectively. The results suggested that the three-wavelength model was the best for fitting, and the determination coefficients of water, soil and sediment data were 0. 788, 0. 933 and 0. 856, respectively. Meanwhile, the nominal best model was validated with the UV-Vis data of 32 soil samples and 36 water samples randomly collected in 2013, showing the RRMSE and MRE were 16. 5% and 16. 9% respectively for soil DOM samples, 10. 32% and 9. 06% respectively for water DOM samples, which further suggested the prediction accuracy was higher in water DOM samples as compared with that in soil DOM samples.

Social impairment of children with autism spectrum disorder affects parental quality of life in different ways.

PubMed

Wang, Ying; Xiao, Lu; Chen, Run-Sen; Chen, Chen; Xun, Guang-Lei; Lu, Xiao-Zi; Shen, Yi-Dong; Wu, Ren-Rong; Xia, Kun; Zhao, Jing-Ping; Ou, Jian-Jun

2018-05-25

This study evaluated the life quality of Chinese parents of preschool children with autism spectrum disorder (ASD) and their association with child social impairment and childcare burden. The participants included 406 families of children with ASD and 513 families with typically developing (TD) children. The findings indicated that parents in the ASD group had a lower quality of life than parents in the TD group, whereas only mother of children with ASD experienced a greater childcare burden than mother with TD children. Lower parental quality of life were associated with higher social impairment of children. To further clarify the correlativity of child social impairment, parental quality of life and childcare burden, the mediation analyses were conducted. The results showed that childcare burden mediated the influence of child social impairment on maternal quality of life, while it has no mediating effect on fathers. It implies that social impairment of children affects parental quality of life in different ways. Copyright © 2018. Published by Elsevier B.V.

Social Phenotypes of Autism Spectrum Disorders and Williams Syndrome: Similarities and Differences

PubMed Central

Asada, Kosuke; Itakura, Shoji

2012-01-01

Autism spectrum disorders (ASD) and Williams syndrome (WS) both are neurodevelopmental disorders, each with a unique social phenotypic pattern. This review article aims to define the similarities and differences between the social phenotypes of ASD and WS. We review studies that have examined individuals with WS using diagnostic assessments such as the Autism Diagnostic Observation Schedule (ADOS), cross-syndrome direct comparison studies, and studies that have individually examined either disorder. We conclude that (1) individuals with these disorders show quite contrasting phenotypes for face processing (i.e., preference to faces and eyes) and sociability (i.e., interest in and motivation to interact with others), and (2) although the ADOS and a direct comparison study on pragmatic language ability suggest more deficits in ASD, individuals with WS are similarly impaired on social cognition and communicative skills. In light of these results, we discuss how cross-syndrome comparisons between ASD and WS can contribute to developmental theory, cognitive neuroscience, and the development and choice of clinical treatments. PMID:22866045

Diagnosis Lost: Differences between Children who Had and who Currently Have an Autism Spectrum Disorder Diagnosis

PubMed Central

Blumberg, Stephen J; Zablotsky, Benjamin; Avila, Rosa M; Colpe, Lisa J; Pringle, Beverly A; Kogan, Michael D

2016-01-01

Autism spectrum disorder (ASD) diagnoses sometimes change due to misdiagnosis, maturation, or treatment. This study uses a probability-based national survey—the Survey of Pathways to Diagnosis and Services—to compare currently diagnosed (n=1420) and previously diagnosed (n=187) children aged 6–17 years based on retrospective parental reports of early concerns about their children’s development, responses to those concerns by doctors and other health care providers, the type of provider who made the first ASD diagnosis, and the ASD subtype diagnoses received (if any). Propensity score matching was used to control for differences between the groups on children’s current level of functioning and other current characteristics that may have been related to diagnosis loss. Approximately 13% of the children ever diagnosed with ASD were estimated to have lost the diagnosis, and parents of 74% of them believe it was changed due to new information. Previously diagnosed children were less likely to have parents with early concerns about verbal skills, nonverbal communication, learning, and unusual gestures or movements. They were also less likely to have been referred to and diagnosed by a specialist. Previously diagnosed children were less likely to have ever received a diagnosis of Asperger’s disorder or autistic disorder. PMID:26489772

Subregional differences in intrinsic amygdala hyperconnectivity and hypoconnectivity in autism spectrum disorder.

PubMed

Kleinhans, Natalia M; Reiter, Maya A; Neuhaus, Emily; Pauley, Greg; Martin, Nathalie; Dager, Stephen; Estes, Annette

2016-07-01

The amygdala is a complex structure with distinct subregions and dissociable functional networks. The laterobasal subregion of the amygdala is hypothesized to mediate the presentation and severity of autism symptoms, although very little data are available regarding amygdala dysfunction at the subregional level. In this study, we investigated the relationship between abnormal amygdalar intrinsic connectivity, autism symptom severity, and anxiety and depressive symptoms. We collected resting state fMRI data on 31 high functioning adolescents and adults with autism spectrum disorder and 38 typically developing (TD) controls aged 14-45. Twenty-five participants with ASD and 28 TD participants were included in the final analyses. ASD participants were administered the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule. Adult participants were administered the Beck Depression Inventory II and the Beck Anxiety Inventory. Functional connectivity analyses were conducted from three amygdalar subregions: centromedial (CM), laterobasal (LB) and superficial (SF). In addition, correlations with the behavioral measures were tested in the adult participants. In general, the ASD group showed significantly decreased connectivity from the LB subregion and increased connectivity from the CM and SF subregions compared to the TD group. We found evidence that social symptoms are primarily associated with under-connectivity from the LB subregion whereas over-connectivity and under-connectivity from the CM, SF and LB subregions are related to co-morbid depression and anxiety in ASD, in brain regions that were distinct from those associated with social dysfunction, and in different patterns than were observed in mildly symptomatic TD participants. Our findings provide new evidence for functional subregional differences in amygdala pathophysiology in ASD. Autism Res 2016, 9: 760-772. © 2015 International Society for Autism Research, Wiley Periodicals, Inc. �

Clinical differences in children with autism spectrum disorder with and without food selectivity.

PubMed

Postorino, Valentina; Sanges, Veronica; Giovagnoli, Giulia; Fatta, Laura Maria; De Peppo, Lavinia; Armando, Marco; Vicari, Stefano; Mazzone, Luigi

2015-09-01

Several studies have described the atypical eating behaviors frequently occurring in children with Autism Spectrum Disorder (ASD), and food selectivity is the most frequent of these problems. The everyday management of mealtime behaviors among children with ASD can have a negative impact on family routines and become a significant stressor for families. However, much remains unknown about why food selectivity is so prevalent among individuals with ASD. The objective of this study was to investigate clinical and behavioral features in individuals with ASD with the aim of identifying distinctive clinical profiles in children with and without food selectivity. A total of 158 children with ASD were enrolled in this study: 79 participants with food selectivity (FS) were age and sex matched with 79 participants without food selectivity (No FS). All participants and their parents completed a battery of psychological tests for a comprehensive evaluation of ASD symptoms, cognitive abilities, adaptive skills, behavioral problems and parental stress level. No statistically significant difference on gastrointestinal symptoms and growth adequacy was found between the FS group and the No FS group. Overall, the FS group showed significantly higher rates of ASD symptoms as compared to the No FS group in the questionnaires completed by parents. Furthermore, parents of the FS group reported significantly higher levels of parental stress and a larger degree of their children's behavioral problems as compared to the No FS group. Finally, there were no differences between the FS and the No FS group on any adaptive skill domain. Our findings suggest that the identification of distinctive clinical and behavioral patterns in children with ASD and food selectivity is a crucial issue for parents and therapists in the daily management. Copyright © 2015 Elsevier Ltd. All rights reserved.

Atmospheric absorption of terahertz radiation and water vapor continuum effects

NASA Astrophysics Data System (ADS)

Slocum, David M.; Slingerland, Elizabeth J.; Giles, Robert H.; Goyette, Thomas M.

2013-09-01

The water vapor continuum absorption spectrum was investigated using Fourier Transform Spectroscopy. The transmission of broadband terahertz radiation from 0.300 to 1.500 THz was recorded for multiple path lengths and relative humidity levels. The absorption coefficient as a function of frequency was determined and compared with theoretical predictions and available water vapor absorption data. The prediction code is able to separately model the different parts of atmospheric absorption for a range of experimental conditions. A variety of conditions were accurately modeled using this code including both self and foreign gas broadening for low and high water vapor pressures for many different measurement techniques. The intensity and location of the observed absorption lines were also in good agreement with spectral databases. However, there was a discrepancy between the resonant line spectrum simulation and the observed absorption spectrum in the atmospheric transmission windows caused by the continuum absorption. A small discrepancy remained even after using the best available data from the literature to account for the continuum absorption. From the experimental and resonant line simulation spectra the air-broadening continuum parameter was calculated and compared with values available in the literature.

Ingestion and absorption of particles derived from different macrophyta in the cockle Cerastoderma edule: effects of food ration.

PubMed

Arambalza, U; Ibarrola, I; Navarro, E; Urrutia, M B

2014-02-01

We analyzed the capacity of the common cockle Cerastoderma edule to utilize detrital food particles obtained from three different macrophytes: the vascular plant Juncus maritimus and two green macroalgae (Ulva lactuca and Enteromorpha sp.). We measured feeding and digestive parameters at three concentrations of detritus (0.5, 1.0 and 3.0 mm(3) l(-1)), so that functional relationships between ingestive and digestive processes could be assessed. Increasing concentrations of detritus (food) resulted in a reduction in filtering activity (clearance rate l h(-1)), but an increase in ingestion rate. Consequently, gut content also increased with increasing food concentration, irrespective of food type. In contrast, the trend followed by absorption efficiency with increasing ingestion rate was determined by food type, being significantly reduced (from 0.63 to 0.11) with Juncus but remaining almost constant with the green macroalgae (0.58 ± 0.07 with Ulva) or only minimally reduced (from 0.66 to 0.48 with Enteromorpha). This differential response had clear consequences for energy uptake: absorption rate increased with increasing particulate organic matter with Enteromorpha but decreased with Juncus. We discuss the possible role of digestive parameters such as digestibility, gut content and gut-residence time in the differential utilization of detrital matter from different vegetal origins by cockles.

Objective measurement of head movement differences in children with and without autism spectrum disorder.

PubMed

Martin, Katherine B; Hammal, Zakia; Ren, Gang; Cohn, Jeffrey F; Cassell, Justine; Ogihara, Mitsunori; Britton, Jennifer C; Gutierrez, Anibal; Messinger, Daniel S

2018-01-01

Deficits in motor movement in children with autism spectrum disorder (ASD) have typically been characterized qualitatively by human observers. Although clinicians have noted the importance of atypical head positioning (e.g. social peering and repetitive head banging) when diagnosing children with ASD, a quantitative understanding of head movement in ASD is lacking. Here, we conduct a quantitative comparison of head movement dynamics in children with and without ASD using automated, person-independent computer-vision based head tracking (Zface). Because children with ASD often exhibit preferential attention to nonsocial versus social stimuli, we investigated whether children with and without ASD differed in their head movement dynamics depending on stimulus sociality. The current study examined differences in head movement dynamics in children with ( n  = 21) and without ASD ( n  = 21). Children were video-recorded while watching a 16-min video of social and nonsocial stimuli. Three dimensions of rigid head movement-pitch (head nods), yaw (head turns), and roll (lateral head inclinations)-were tracked using Zface. The root mean square of pitch, yaw, and roll was calculated to index the magnitude of head angular displacement (quantity of head movement) and angular velocity (speed). Compared with children without ASD, children with ASD exhibited greater yaw displacement, indicating greater head turning, and greater velocity of yaw and roll, indicating faster head turning and inclination. Follow-up analyses indicated that differences in head movement dynamics were specific to the social rather than the nonsocial stimulus condition. Head movement dynamics (displacement and velocity) were greater in children with ASD than in children without ASD, providing a quantitative foundation for previous clinical reports. Head movement differences were evident in lateral (yaw and roll) but not vertical (pitch) movement and were specific to a social rather than nonsocial

Generational Differences in Internalized Transnegativity and Psychological Distress Among Feminine Spectrum Transgender People.

PubMed

Jackman, Kasey B; Dolezal, Curtis; Bockting, Walter O

2018-01-01

This study examined internalized transnegativity and psychological distress in two age groups of transgender individuals who identified their gender identity on the feminine spectrum (rather than congruent with their male sex assigned at birth). Due to greater visibility and acceptance of gender diversity in the United States, we hypothesized that internalized transnegativity would be lower in the younger compared with the older group, and that the younger generation would, therefore, report lower levels of psychological distress than the older generation. The study sample consisted of trans-feminine individuals (N = 440) who completed a online survey of the U.S. transgender population and comprised a younger group aged 18-24 years (n = 133) and an older group aged 40 years and older (n = 307). Internalized transnegativity was assessed using the Transgender Identity Survey, and psychological distress was assessed with the Brief Symptom Inventory 18. We used regression and mediation analysis to examine differences between the two groups. Contrary to our expectations, the older group reported significantly lower levels of both internalized transnegativity and psychological distress compared with the younger group. Internalized transnegativity partially mediated the relationship between age group and psychological distress. Despite greater visibility of transgender people and increasing acceptance of gender diversity in the United States, the younger trans-feminine individuals reported more psychological distress than the older transfeminine individuals, which was, in part, related to internalized transnegativity. Trans-feminine individuals may benefit from culturally sensitive and clinically competent mental health services to alleviate internalized transnegativity and psychological distress.

Gender differences in autism spectrum disorders: Divergence among specific core symptoms.

PubMed

Beggiato, Anita; Peyre, Hugo; Maruani, Anna; Scheid, Isabelle; Rastam, Maria; Amsellem, Frederique; Gillberg, Carina I; Leboyer, Marion; Bourgeron, Thomas; Gillberg, Christopher; Delorme, Richard

2017-04-01

Community-based studies have consistently shown a sex ratio heavily skewed towards males in autism spectrum disorders (ASD). The factors underlying this predominance of males are largely unknown, but the way girls score on standardized categorical diagnostic tools might account for the underrecognition of ASD in girls. Despite the existence of different norms for boys and girls with ASD on several major screening tests, the algorithm of the Autism Diagnosis Interview-Revised (ADI-R) has not been reformulated. The aim of our study was to investigate which ADI-R items discriminate between males and females, and to evaluate their weighting in the final diagnosis of autism. We then conducted discriminant analysis (DA) on a sample of 594 probands including 129 females with ASD, recruited by the Paris Autism Research International Sibpair (PARIS) Study. A replication analysis was run on an independent sample of 1716 probands including 338 females with ASD, recruited through the Autism Genetics Resource Exchange (AGRE) program. Entering the raw scores for all ADI-R items as independent variables, the DA correctly classified 78.9% of males and 72.9% of females (P < 0.001) in the PARIS cohort, and 72.2% of males and 68.3% of females (P < 0.0001) in the AGRE cohort. Among the items extracted by the stepwise DA, four belonged to the ADI-R algorithm used for the final diagnosis of ASD. In conclusion, several items of the ADI-R that are taken into account in the diagnosis of autism significantly differentiates between males and females. The potential gender bias thus induced may participate in the underestimation of the prevalence of ASD in females. Autism Res 2016,. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 680-689. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Generational Differences in Internalized Transnegativity and Psychological Distress Among Feminine Spectrum Transgender People

PubMed Central

Dolezal, Curtis; Bockting, Walter O.

2018-01-01

Abstract Purpose: This study examined internalized transnegativity and psychological distress in two age groups of transgender individuals who identified their gender identity on the feminine spectrum (rather than congruent with their male sex assigned at birth). Due to greater visibility and acceptance of gender diversity in the United States, we hypothesized that internalized transnegativity would be lower in the younger compared with the older group, and that the younger generation would, therefore, report lower levels of psychological distress than the older generation. Methods: The study sample consisted of trans-feminine individuals (N = 440) who completed a online survey of the U.S. transgender population and comprised a younger group aged 18–24 years (n = 133) and an older group aged 40 years and older (n = 307). Internalized transnegativity was assessed using the Transgender Identity Survey, and psychological distress was assessed with the Brief Symptom Inventory 18. We used regression and mediation analysis to examine differences between the two groups. Results: Contrary to our expectations, the older group reported significantly lower levels of both internalized transnegativity and psychological distress compared with the younger group. Internalized transnegativity partially mediated the relationship between age group and psychological distress. Conclusion: Despite greater visibility of transgender people and increasing acceptance of gender diversity in the United States, the younger trans-feminine individuals reported more psychological distress than the older transfeminine individuals, which was, in part, related to internalized transnegativity. Trans-feminine individuals may benefit from culturally sensitive and clinically competent mental health services to alleviate internalized transnegativity and psychological distress. PMID:29099335

Gender differences in emotionality and sociability in children with autism spectrum disorders

PubMed Central

2014-01-01

Background Four times as many males are diagnosed with high functioning autism compared to females. A growing body of research that focused on females with autism spectrum disorder (ASD) questions the assumption of gender invariance in ASD. Clinical observations suggest that females with ASD superficially demonstrate better social and emotional skills than males with ASD, which may camouflage other diagnostic features. This may explain the under-diagnosis of females with ASD. Methods We hypothesised that females with ASD would display better social skills than males with ASD on a test of friendship and social function. One hundred and one 10- to 16-year-olds (ASD females, n = 25; typically developing (TD) females, n = 25; ASD males, n = 25; TD males, n = 26) were interviewed (using the friendship questionnaire (FQ)) with high scores indicating the child has close, empathetic and supportive relationships. One parent of each child completed the FQ to assess whether there are differences in perception of friendships between parents and children. Results It was found that, independent of diagnosis, females demonstrated higher scores on the FQ than males. Further, regardless of gender, children with ASD demonstrated lower scores than TD children. Moreover, the effect of ASD was independent of gender. Interestingly, females with ASD and TD males displayed similar scores on the FQ. Conclusions This finding is supported by clinical reports that females with ASD have more developed social skills than males with ASD. Further research is now required to examine the underlying causes for this phenomenon in order to develop gender-appropriate diagnostic criteria and interventions for ASD. PMID:24576331

Similarities and Differences in Decision-Making Impairments between Autism Spectrum Disorder and Schizophrenia.

PubMed

Zhang, Long; Tang, Jiulai; Dong, Yi; Ji, Yifu; Tao, Rui; Liang, Zhitu; Chen, Jingsong; Wu, Yun; Wang, Kai

2015-01-01

Although individuals with autism spectrum disorders (ASD) and schizophrenia (SCH) share overlapping characteristics and may perform similarly on many cognitive tasks, cognitive dysfunctions common to both disorders do not necessarily share the same underlying mechanisms. Decision-making is currently a major research interest for both ASD and SCH. The aim of the present study was to make direct comparisons of decision-making and disorder-specific underlying neuropsychological mechanisms between the two disorders. Thirty-seven participants with ASD, 46 patients with SCH, and 80 healthy controls (HC) were assessed with the Iowa Gambling Task (IGT), which measures decision-making under ambiguity, and the Game of Dice Task (GDT), which measures decision-making under risk. The results revealed that both the ASD and SCH groups had deficits for both the IGT and the GDT compared with the HC. More importantly, in the IGT, participants with ASD displayed a preference for deck A, indicating that they had more sensitivity to the magnitude of loss than to the frequency of loss, whereas patients with SCH displayed a preference for deck B, indicating that they showed more sensitivity to the frequency of loss than to the magnitude of loss. In the GDT, the impaired performance might be due to the deficits in executive functions in patients with SCH, whereas the impaired performance might be due to the deficits in feedback processing in participants with ASD. These findings demonstrate that there are similar impairments in decision-making tasks between ASD and SCH; however, these two disorders may have different impairment mechanisms.

Differences in change blindness to real-life scenes in adults with autism spectrum conditions.

PubMed

Ashwin, Chris; Wheelwright, Sally; Baron-Cohen, Simon

2017-01-01

People often fail to detect large changes to visual scenes following a brief interruption, an effect known as 'change blindness'. People with autism spectrum conditions (ASC) have superior attention to detail and better discrimination of targets, and often notice small details that are missed by others. Together these predict people with autism should show enhanced perception of changes in simple change detection paradigms, including reduced change blindness. However, change blindness studies to date have reported mixed results in ASC, which have sometimes included no differences to controls or even enhanced change blindness. Attenuated change blindness has only been reported to date in ASC in children and adolescents, with no study reporting reduced change blindness in adults with ASC. The present study used a change blindness flicker task to investigate the detection of changes in images of everyday life in adults with ASC (n = 22) and controls (n = 22) using a simple change detection task design and full range of original scenes as stimuli. Results showed the adults with ASC had reduced change blindness compared to adult controls for changes to items of marginal interest in scenes, with no group difference for changes to items of central interest. There were no group differences in overall response latencies to correctly detect changes nor in the overall number of missed detections in the experiment. However, the ASC group showed greater missed changes for marginal interest changes of location, showing some evidence of greater change blindness as well. These findings show both reduced change blindness to marginal interest changes in ASC, based on response latencies, as well as greater change blindness to changes of location of marginal interest items, based on detection rates. The findings of reduced change blindness are consistent with clinical reports that people with ASC often notice small changes to less salient items within their environment, and are in

Age Related Differences of Executive Functioning Problems in Everyday Life of Children and Adolescents in the Autism Spectrum

ERIC Educational Resources Information Center

van den Bergh, Sanne F. W. M.; Scheeren, Anke M.; Begeer, Sander; Koot, Hans M.; Geurts, Hilde M.

2014-01-01

Numerous studies investigated executive functioning (EF) problems in people with autism spectrum disorders (ASD) using laboratory EF tasks. As laboratory task performances often differ from real life observations, the current study focused on EF in everyday life of 118 children and adolescents with ASD (6-18 years). We investigated age-related and…

Age Differences in Emergency Department Visits and Inpatient Hospitalizations in Preadolescent and Adolescent Youth with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Schlenz, Alyssa M.; Carpenter, Laura A.; Bradley, Catherine; Charles, Jane; Boan, Andrea

2015-01-01

This paper evaluated age differences in emergency department care and inpatient hospitalizations in 252 preadolescent and adolescent youth with autism spectrum disorders (ASDs; ages 9-18). Records from youth with ASDs were linked to acute care utilization records and were compared to a demographically similar comparison group of youth without ASDs…

Narratives of Girls and Boys with Autism Spectrum Disorders: Gender Differences in Narrative Competence and Internal State Language

ERIC Educational Resources Information Center

Kauschke, Christina; van der Beek, Bettina; Kamp-Becker, Inge

2016-01-01

Since gender differences in the symptomatology of autism spectrum disorder (ASD) are not well understood, the current study examines the communicative skills of males and females with ASD. Narrative competence and internal state language (ISL) was investigated using narrations elicited by a wordless picture book. 11 girls and 11 boys with ASD and…

Sex Differences in Autism Spectrum Disorder: An Examination of Developmental Functioning, Autistic Symptoms, and Coexisting Behavior Problems in Toddlers

ERIC Educational Resources Information Center

Hartley, Sigan L.; Sikora, Darryn M.

2009-01-01

Little is known about the female presentation of autism spectrum disorder (ASD) during early childhood. We investigated sex differences in developmental profiles using the Mullen Scales of Early Learning, autistic symptoms on the ADOS-G, and coexisting behavior problems on the CBCL in 157 boys and 42 girls with ASD aged 1.5-3.9 years. Overall,…

Ultrasonic velocity and absorption study of binary mixtures of cyclohexane with acrylonitrile by interferometric method at different frequencies

NASA Astrophysics Data System (ADS)

Pawar, N. R.; Chimankar, O. P.; Bhandakkar, V. D.; Padole, N. N.

2012-12-01

The ultrasonic velocity (u), absorption (α), density (ρ), and viscosity (η) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (βa), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.

Laser-induced periodic surface structures formation: investigation of the effect of nonlinear absorption of laser energy in different materials

NASA Astrophysics Data System (ADS)

Levy, Yoann; Bulgakova, Nadezhda M.; Mocek, Tomáš

2017-05-01

To get insight into laser-induced periodic surface structures (LIPSS) formation, the relaxation of a modulation in the temperature profile is investigated numerically on surfaces of two different kinds of materials (metals and dielectrics; gold and fused silica as examples) upon irradiation by ultrashort laser pulses. The temperature modulation is assumed to originate from the interference between the incoming laser pulse and the surface electromagnetic wave, which is considered as the main mechanism of LIPSS formation. For comparative studies of laser energy dissipation, a simplified 2D approach is used. It is based on the two-temperature model (TTM) and considers the mechanisms of nonlinear absorption of laser light (multiphoton ionization in fused silica; temperature-dependent thermophysical and optical properties in gold) and relaxation (electron trapping to excitonic states in fused silica). The TTM is coupled with the Drude model, considering the evolution of optical properties as a function of free-carrier density and/or temperature. The development and decay of the lattice temperature modulation, which can govern the LIPSS formation, is followed during electron-lattice thermalization time and beyond. It is shown that strong temperature gradients can form along the surfaces of both kinds of materials under study within the fluence range typical for LIPSS formation. Considerable changes in optical properties of these materials are found as a function of time, including metals, for which a constant reflectivity is usually assumed. Effects of nonlinear absorption on the surface temperature dynamics are reported.

K- and L-edge X-ray absorption spectrum calculations of closed-shell carbon, silicon, germanium, and sulfur compounds using damped four-component density functional response theory.

PubMed

Fransson, Thomas; Burdakova, Daria; Norman, Patrick

2016-05-21

X-ray absorption spectra of carbon, silicon, germanium, and sulfur compounds have been investigated by means of damped four-component density functional response theory. It is demonstrated that a reliable description of relativistic effects is obtained at both K- and L-edges. Notably, an excellent agreement with experimental results is obtained for L2,3-spectra-with spin-orbit effects well accounted for-also in cases when the experimental intensity ratio deviates from the statistical one of 2 : 1. The theoretical results are consistent with calculations using standard response theory as well as recently reported real-time propagation methods in time-dependent density functional theory, and the virtues of different approaches are discussed. As compared to silane and silicon tetrachloride, an anomalous error in the absolute energy is reported for the L2,3-spectrum of silicon tetrafluoride, amounting to an additional spectral shift of ∼1 eV. This anomaly is also observed for other exchange-correlation functionals, but it is seen neither at other silicon edges nor at the carbon K-edge of fluorine derivatives of ethene. Considering the series of molecules SiH4-XFX with X = 1, 2, 3, 4, a gradual divergence from interpolated experimental ionization potentials is observed at the level of Kohn-Sham density functional theory (DFT), and to a smaller extent with the use of Hartree-Fock. This anomalous error is thus attributed partly to difficulties in correctly emulating the electronic structure effects imposed by the very electronegative fluorines, and partly due to inconsistencies in the spurious electron self-repulsion in DFT. Substitution with one, or possibly two, fluorine atoms is estimated to yield small enough errors to allow for reliable interpretations and predictions of L2,3-spectra of more complex and extended silicon-based systems.

Spectrum Project

NASA Image and Video Library

2017-10-16

Inside the Spectrum prototype unit, organisms in a Petri plate are exposed to different colors of lighting. The device works by exposing organisms to different colors of fluorescent light while a camera records what's happening with time-lapse photography. Results from the Spectrum project will shed light on which living things are best suited for long-duration flights into deep space.

A Preliminary Study of Gender Differences in Autobiographical Memory in Children with an Autism Spectrum Disorder

ERIC Educational Resources Information Center

Goddard, Lorna; Dritschel, Barbara; Howlin, Patricia

2014-01-01

Autobiographical memory was assessed in 24 children (12 male, 12 female, aged between 8 and 16 years) with autism spectrum disorder (ASD) and a comparison group of 24 typically developing (TD) children matched for age, IQ, gender and receptive language. Results suggested that a deficit in specific memory retrieval in the ASD group was more…

What Difference Does It Make? Implicit, Explicit and Complex Social Cognition in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Schaller, Ulrich M.; Rauh, Reinhold

2017-01-01

We tested social cognition abilities of adolescents with autism spectrum disorders (ASD) and neurotypically developed peers (NTD). A multi-faceted test-battery including facial emotion categorization (FEC), classical false belief tasks (FBT), and complex social cognition (SC), yielded significantly lower accuracy rates for FEC and complex SC tasks…

Sensitivity to Differences between Enjoyment and Non-Enjoyment Smiles in Children with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Blampied, Meredith; Johnston, Lucy; Miles, Lynden; Liberty, Kathleen

2010-01-01

The sensitivity of male children (5-15 years) with and without autism spectrum disorder (ASD) to the affective state of others was tested using an emotion recognition task. Only children without ASD could reliably differentiate between enjoyment and non-enjoyment smiles. Results are considered in terms of the social impairments of children with…

Review of Gender Differences in Core Symptomatology in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Rivet, Tessa Taylor; Matson, Johnny L.

2011-01-01

A preponderance of males with autism spectrum disorders (ASD) has been evident since the initial writings on the topic. This male predominance has consistently emerged in all ASD research to date in epidemiological as well as clinical populations. Despite this long recognized gender disparity in ASD, surprisingly there is a paucity of research…

Lexical Effects on Children's Speech Processing: Individual Differences Reflected in the Autism-Spectrum Quotient (AQ)

ERIC Educational Resources Information Center

Ota, Mitsuhiko; Stewart, Mary E.; Petrou, Alexandra M.; Dickie, Catherine

2015-01-01

Purpose: This study was undertaken to examine whether children exhibit the same relationship that adults show between lexical influence on phoneme identification and individual variation on the Autism-Spectrum Quotient (AQ). Method: Data from 62 4- to 7-year-olds with no diagnosis of autism were analyzed. The main task involved identification of…

Explaining Differences in Age at Autism Spectrum Disorder Diagnosis: A Critical Review

ERIC Educational Resources Information Center

Daniels, Amy M.; Mandell, David S.

2014-01-01

The diagnosis of autism is often delayed, which translates into a missed opportunity to provide treatment during a critical developmental period. This study reviews studies that assessed factors associated with age at autism spectrum disorder diagnosis and provides recommendations on future research, programs, and policies to improve early…

Cortisol Responsivity Differences in Children with Autism Spectrum Disorders during Free and Cooperative Play

ERIC Educational Resources Information Center

Schupp, Clayton W.; Simon, David; Corbett, Blythe A.

2013-01-01

Children with autism spectrum disorder (ASD) demonstrate significant heterogeneity in their profiles of social interaction and stress responsivity. We evaluated behavior and stress response in 52 male children ages 8-12 in a naturalistic playground interaction paradigm involving a child with ASD, a typically developing peer, and a same-age…

Different Verbal Learning Strategies in Autism Spectrum Disorder: Evidence from the Rey Auditory Verbal Learning Test

ERIC Educational Resources Information Center

Bowler, Dermot M.; Limoges, Elyse; Mottron, Laurent

2009-01-01

The Rey Auditory Verbal Learning Test, which requires the free recall of the same list of 15 unrelated words over 5 trials, was administered to 21 high-functioning adolescents and adults with autism spectrum disorder (ASD) and 21 matched typical individuals. The groups showed similar overall levels of free recall, rates of learning over trials and…

Does Nutritional Intake Differ between Children with Autism Spectrum Disorders and Children with Typical Development?

ERIC Educational Resources Information Center

Herndon, Alison C.; DiGuiseppi, Carolyn; Johnson, Susan L.; Leiferman, Jenn; Reynolds, Ann

2009-01-01

Consumption of macro- and micronutrients and food group servings by children with autism spectrum disorders (ASDs; n = 46) and typical development (n = 31) were compared using 3-day diet records. Children with ASDs consumed significantly more vitamin B6 and E and non-dairy protein servings, less calcium, and fewer dairy servings (p less than…

Diagnosis Lost: Differences between Children Who Had and Who Currently Have an Autism Spectrum Disorder Diagnosis

ERIC Educational Resources Information Center

Blumberg, Stephen J.; Zablotsky, Benjamin; Avila, Rosa M.; Colpe, Lisa J.; Pringle, Beverly A.; Kogan, Michael D.

2016-01-01

Autism spectrum disorder diagnoses sometimes change due to misdiagnosis, maturation, or treatment. This study uses a probability-based national survey--the Survey of Pathways to Diagnosis and Services--to compare currently diagnosed (n = 1,420) and previously diagnosed (n = 187) children aged 6-17 years based on retrospective parental reports of…

Cognitive, Adaptive, and Psychosocial Differences between High Ability Youth with and without Autism Spectrum Disorder

ERIC Educational Resources Information Center

Doobay, Alissa F.; Foley-Nicpon, Megan; Ali, Saba R.; Assouline, Susan G.

2014-01-01

Research on Autism Spectrum Disorder (ASD) is thriving; however, scant empirical research has investigated how ASD manifests in high ability youth. Further research is necessary to accurately differentiate high ability students with ASD from those without the disorder, and thus decrease the risk of misdiagnosis. The purpose of the present study is…

Widespread White Matter Differences in Children and Adolescents with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Vogan, V. M.; Morgan, B. R.; Leung, R. C.; Anagnostou, E.; Doyle-Thomas, K.; Taylor, M. J.

2016-01-01

Diffusion tensor imaging studies show white matter (WM) abnormalities in children with autism spectrum disorder (ASD). However, investigations are often limited by small samples, particularly problematic given the heterogeneity of ASD. We explored WM using DTI in a large sample of 130 children and adolescents (7-15 years) with and without ASD,…

Sex Differences in Internalizing Problems during Adolescence in Autism Spectrum Disorder

ERIC Educational Resources Information Center

Oswald, Tasha M.; Winter-Messiers, Mary Ann; Gibson, Brandon; Schmidt, Alexandra M.; Herr, Cynthia M.; Solomon, Marjorie

2016-01-01

We hypothesized that the double hit conferred by sex and diagnosis increases the risk for internalizing disorders in adolescent females with autism spectrum disorder (ASD). In a sample of 32 adolescents with ASD and 32 controls, we examined the effects of sex, diagnostic factors, and developmental stages on depression and anxiety. A 3-way…

Cognitive Ability Is Associated with Different Outcome Trajectories in Autism Spectrum Disorders

ERIC Educational Resources Information Center

Ben-Itzchak, Esther; Watson, Linda R.; Zachor, Ditza A.

2014-01-01

Variability in clinical expression and in intervention outcome has been described in autism spectrum disorder (ASD). The study examined progress after 1 and 2 years of intervention and compared the impact of baseline cognitive ability on outcome trajectories in 46 children (m = 25.5 months) with ASD. The entire group showed a gradual decrease in…

Gender Differences in Co-Morbid Psychopathology and Clinical Management in Adults with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Tsakanikos, Elias; Underwood, Lisa; Kravariti, Eugenia; Bouras, Nick; McCarthy, Jane

2011-01-01

The present study examined rates of co-morbid psychopathology and clinical management/care pathways in adult females (N = 50) and males (N = 100) with autism spectrum disorders (ASD) and intellectual disability (ID) living in community settings. We also compared a sub-sample (N = 60) with ASD to an age-, gender- and ID-matched control group (N =…

Analyzing radiation absorption difference of dental substance by using Dual CT

NASA Astrophysics Data System (ADS)

Yu, H.; Lee, H. K.; Cho, J. H.; Yang, H. J.; Ju, Y. S.

2015-07-01

The purpose of this study was to evaluate the changes of noise and computer tomography (CT) number in each dental substance, by using the metal artefact reduction algorithm; we used dual CT for this study. For the study, we produced resin, titanium, gypsum, and wax that are widely used by dentists. In addition, we made nickel to increase the artefact. While making the study materials, we made sure that there is no difficulty when inserting the substances inside phantom. In order to study, we scanned before and after using the metal artefact reduction algorithm. We conducted an average analysis of CT number and noise, before and after using the metal artefact reduction algorithm. As a result, there was no difference in CT number and noise before and after using the metal artefact reduction algorithm. However, when it comes to the noise value in each substance, wax's noise value was the lowest whereas titanium's noise value was the highest, after applying the metal artefact reduction algorithm. In nickel, CT number and noise value from artefact area showed a decreased noise value when applying the metal artefact reduction algorithm. In conclusion, we assumed that we could increase the effectiveness of CT examination by applying dual energy's metal artefact reduction algorithm.

Comparison of hatching egg characteristics, embryo development, yolk absorption, hatch window, and hatchability of Pekin Duck eggs of different weights.

PubMed

Ipek, A; Sozcu, A

2017-10-01

This study was carried out to determine the hatching egg characteristics, embryo development and yolk absorption during incubation, hatch window, and hatchability of Pekin duck eggs of different weights. A total of 960 hatching eggs was obtained from a breeder flock 35 to 36 wk of age. The eggs were classed into 3 weight categories: "light" (L; <75 g), "medium" (M; 76 to 82 g), and "heavy" (H; >83 g). The albumen weight was the highest in the heavy eggs, whereas the yolk weight was higher in the medium and heavy eggs. Egg breaking strength was the highest with a value of 2.5 kg/cm2 in light eggs, whereas the thinnest eggshell (0.3862 mm) was observed in heavy eggs. pH of albumen and yolk was similar and ranged from 8.8 to 8.9 and 5.9 to 6.0, respectively. On d 14 of incubation, yolk sac weight was found higher in the medium and heavy eggs. Additionally, the dry matter of the embryo and yolk sac differed among the egg weight groups during the incubation period. Interestingly, on d 25 of incubation, the embryo weight was higher in the light and heavy eggs (35.2 and 36.3 g, respectively) than in the medium eggs (29.8 g). These findings showed that embryo growth was affected by yolk absorption and dry matter accumulation. The hatchability of total and fertile eggs was lower for the heavy eggs than the light and medium eggs. The chick weight was 42.8, 48.4, and 54.9 g in light, medium, and heavy eggs, respectively. A percentage of 34.2, 36, and 31.6% of chicks from light, medium, and heavy eggs, hatched between 637 and 648 h, 39.6, 36.2, and 32.9% between 649 and 660 h, 26.2, 27.8, and 35.5% between 661 and 672 h of incubation, respectively. In conclusion, hatching egg quality, embryo development and yolk absorption during incubation, hatch window, and hatchability were affected by egg weight in Pekin ducks. © 2017 Poultry Science Association Inc.

Determination of K-shell absorption jump factors and jump ratios for La2O3, Ce and Gd using two different methods

NASA Astrophysics Data System (ADS)

Akman, Ferdi; Durak, Rıdvan; Kaçal, Mustafa Recep; Turhan, Mehmet Fatih; Akdemir, Fatma

2015-02-01

The K shell absorption jump factors and jump ratios for La2O3, Ce and Gd samples have been determined using the gamma or X-ray attenuation and EDXRF methods. It is the first time that the K shell absorption jump factor and jump ratio have been discussed for present elements using two different methods. To detect K X-rays, a high resolution Si(Li) detector was used. The experimental results of K shell absorption jump factors and jump ratios were compared with the theoretically calculated ones.

Spectrum Project

NASA Image and Video Library

2017-10-16

Inside the Spectrum prototype unit, organisms in a Petri plate are exposed to blue excitation lighting. The device works by exposing organisms to different colors of fluorescent light while a camera records what's happening with time-lapse photography. Results from the Spectrum project will shed light on which living things are best suited for long-duration flights into deep space.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, D.A.; Keller, R.A.

1984-05-08

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect have been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical path length of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10[sup [minus]5] cm[sup [minus]1] can then be determined in the presence of background absorptions in excess of 10[sup [minus]3] cm[sup [minus]1]. In addition, the smallest absorption measured with the instant apparatus and method is about 5 [times] 10[sup [minus]6] cm[sup [minus]1]. 6 figs.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, David A.; Keller, Richard A.

1984-01-01

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10.sup.-5 cm.sup.-1 can then be determined in the presence of background absorptions in excess of 10.sup.-3 cm.sup.-1. In addition, the smallest absorption measured with the instant apparatus and method is about 5.times. 10.sup.-6 cm.sup.-1.

Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

DOEpatents

Cremers, D.A.; Keller, R.A.

1982-06-08

An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10/sup -5/ cm/sup -1/ can then be determined in the presence of background absorptions in excess of 10/sup -3/ cm/sup -1/. In addition, the smallest absorption measured with the instant apparatus and method is about 5 x 10/sup -6/ cm/sup -1/.

Analysis on the impact of FBG reflectance spectrum with different optical fiber connection in vacuum thermal environment

NASA Astrophysics Data System (ADS)

Zhang, Jingchuan; Zhang, Wen; Lv, Jianfeng; Liang, Shuo; Wang, Lei; Li, Xiyuan

2018-01-01

To satisfy the application of fiber grating sensor technology in high vacuum thermal environment, FBG on sleeve compactly single model fiber with two typical different kind of connection such as fiber splicing and optical fiber connector are researched. Influence of the different connection to the characteristic of FBG reflectance spectrum in high vacuum thermal environment is analyzed and verified. First, experimental program of influence on FBG reflection spectrum characteristics is designed. Then, a hardware-in-the-loop detection platform is set up. Finally, the influence of temperature and vacuum on the reflection peak power of FBG with two typical different connections under high vacuum thermal environment is studied and verified. Experimental results indicate that: when vacuum varied from normal pressure to 10-4Pa level and then return to normal pressure, temperature of two different single-mode optical fiber connection dropped to -196 °C from room temperature and then returned to room temperature, after 224 hours, the peak power of the FBG reflectance spectrum did not change. It provided the experimental basis for the application of optical fiber sensing technology in high vacuum (pressure about 10-4Pa level) and thermal environment (-196 °C temperature cycle).

Variations of the TeV energy spectrum at different flux levels of Mkn 421 observed with the HEGRA system of Cherenkov telescopes

NASA Astrophysics Data System (ADS)

Aharonian, F.; Akhperjanian, A.; Beilicke, M.; Bernlöhr, K.; Börst, H.; Bojahr, H.; Bolz, O.; Coarasa, T.; Contreras, J.; Cortina, J.; Costamante, L.; Denninghoff, S.; Fonseca, V.; Girma, M.; Götting, N.; Heinzelmann, G.; Hermann, G.; Heusler, A.; Hofmann, W.; Horns, D.; Jung, I.; Kankanyan, R.; Kestel, M.; Kettler, J.; Kohnle, A.; Konopelko, A.; Kornmeyer, H.; Kranich, D.; Krawczynski, H.; Lampeitl, H.; Lopez, M.; Lorenz, E.; Lucarelli, F.; Mang, O.; Meyer, H.; Mirzoyan, R.; Milite, M.; Moralejo, A.; Ona, E.; Panter, M.; Plyasheshnikov, A.; Pühlhofer, G.; Rauterberg, G.; Reyes, R.; Rhode, W.; Ripken, J.; Rowell, G.; Sahakian, V.; Samorski, M.; Schilling, M.; Siems, M.; Sobzynska, D.; Stamm, W.; Tluczykont, M.; Völk, H. J.; Wiedner, C. A.; Wittek, W.; Remillard, R. A.

2002-10-01

The nearby BL Lacertae (BL Lac) object Markarian 421 (Mkn 421) at a red shift z=0.031 was observed to undergo strong TeV gamma -ray outbursts in the observational periods from December 1999 until May 2001. The time averaged flux level F(E>1 TeV) in the 1999/2000 season was (1.43+/-0.04) x 10-11 ph cm-2 s-1, whereas in the 2000/2001 season the average integral flux increased to (4.19+/-0.04) x 10-11 ph cm-2 s-1. Both energy spectra are curved and well fit by a power law with an exponential cut-off energy at 3.6(+0.4-0.3)_stat(+0.9-0.8)_sys TeV. The respective energy spectra averaged over each of the two time periods indicate a spectral hardening for the 2000/2001 spectrum. The photon index changes from 2.39+/-0.09_stat for 1999/2000 to 2.19+/-0.02_stat in 2000/2001. The energy spectra derived for different average flux levels ranging from 0.5 to 10 x 10-11 ph cm-2 s-1 follow a clear correlation of photon index and flux level. Generally, the energy spectra are harder for high flux levels. From January to April 2001 Mkn 421 showed rapid variability (doubling time as short as 20 min), accompanied with a spectral hardening with increasing flux level within individual nights. For two successive nights (MJD 51989-51991, March 21-23, 2001), this correlation of spectral hardness and change in flux has been observed within a few hours. The cut-off energy for the Mkn 421 TeV spectrum remains within the errors constant for the different flux levels and differs by Delta E=2.6+/-0.6_stat+/-0.6_sys TeV from the value determined for Mkn 501. This indicates that the observed exponential cut-off in the energy spectrum of Mkn 421 is not solely caused by absorption of multi-TeV photons by pair-production processes with photons of the extragalactic near/mid infrared background radiation.

Different verbal learning strategies in autism spectrum disorder: evidence from the Rey Auditory Verbal Learning Test.

PubMed

Bowler, Dermot M; Limoges, Elyse; Mottron, Laurent

2009-06-01

The Rey Auditory Verbal Learning Test, which requires the free recall of the same list of 15 unrelated words over 5 trials, was administered to 21 high-functioning adolescents and adults with autism spectrum disorder (ASD) and 21 matched typical individuals. The groups showed similar overall levels of free recall, rates of learning over trials and subjective organisation of their recall. However, the primacy portion of the serial position curve of the ASD participants showed slower growth over trials than that of the typical participants. The implications of this finding for our understanding of memory in ASD are discussed.

Wavelength selection for portable noninvasive blood component measurement system based on spectral difference coefficient and dynamic spectrum

NASA Astrophysics Data System (ADS)

Feng, Ximeng; Li, Gang; Yu, Haixia; Wang, Shaohui; Yi, Xiaoqing; Lin, Ling

2018-03-01

Noninvasive blood component analysis by spectroscopy has been a hotspot in biomedical engineering in recent years. Dynamic spectrum provides an excellent idea for noninvasive blood component measurement, but studies have been limited to the application of broadband light sources and high-resolution spectroscopy instruments. In order to remove redundant information, a more effective wavelength selection method has been presented in this paper. In contrast to many common wavelength selection methods, this method is based on sensing mechanism which has a clear mechanism and can effectively avoid the noise from acquisition system. The spectral difference coefficient was theoretically proved to have a guiding significance for wavelength selection. After theoretical analysis, the multi-band spectral difference coefficient-wavelength selection method combining with the dynamic spectrum was proposed. An experimental analysis based on clinical trial data from 200 volunteers has been conducted to illustrate the effectiveness of this method. The extreme learning machine was used to develop the calibration models between the dynamic spectrum data and hemoglobin concentration. The experiment result shows that the prediction precision of hemoglobin concentration using multi-band spectral difference coefficient-wavelength selection method is higher compared with other methods.

Research on influence of different cover to the characteristic of FBG reflectance spectrum in vacuum thermal environment

NASA Astrophysics Data System (ADS)

Pei, Yifei; Zhang, Jingchuan; Zhang, Luosha; Liu, Yang; Zhang, Lina; Chen, Shiyu

2018-01-01

To satisfy the application of fiber grating sensor technology in high vacuum thermal environment, two different kinds of sleeve compactly single model fiber covered by acrylate and polyimide are researched. Influence of the cover to the characteristic of FBG reflectance spectrum in high vacuum thermal environment is analyzed and verified. First, transmission characteristic of single model fiber in high vacuum thermal environment is analyzed by solve the equation of heat conduction. Then, experimental program of influence on FBG reflection spectrum characteristics is designed and a hardware-in-the-loop detection platform is set up. Finally, the influence of temperature and vacuum on the reflection peak power of FBG in different coating single-mode transmission fiber under high vacuum thermal environment is studied and verified. Experimental results indicate that: when vacuum varied from normal pressure to 10-4Pa level and then return to normal pressure, temperature of two different coating single-mode transmission fiber dropped to -196 ° from room temperature and then returned to room temperature, after 224 hours, the peak power of the FBG reflectance spectrum did not change. It provided the theoretical and experimental basis for the application of optical fiber sensing technology in high vacuum (pressure about 10-4Pa level) and thermal environment (-196 ° 25 ° temperature cycle) .

Stimulating effects of a diet negative in dietary cation-anion difference on calcium absorption from the rumen in sheep.

PubMed

Wilkens, M R; Praechter, C; Breves, G; Schröder, B

2016-02-01

The concept of feeding anionic salts in late gestation is widely used to prevent milk fever in dairy cows. While the effects of these diets on renal Ca excretion and tissue responsiveness towards parathyroid hormone have clearly been demonstrated, data on a potential impact on gastrointestinal Ca absorption are conflicting. Therefore, the aim of this study was to investigate the influence of feeding a diet negative in dietary cation-anion difference (DCAD) on ruminal mineral concentrations, fermentation products, electrophysiological properties of rumen epithelia and Ca flux rates. For this purpose, sheep were kept for 3 weeks on diets that were either positive or negative in DCAD. The induction of a compensated hyperchloremic metabolic acidosis could be demonstrated by increased plasma Cl and enhanced concentrations of ionised Ca, while plasma concentrations of HCO3- and base excess were decreased with the low DCAD diet. Neither transmural potential differences nor fermentation products were affected, but ruminal concentrations of Cl and Mg as well as the relation of ionised to total Ca were increased. Ussing chamber experiments revealed alterations of electrophysiological parameters and an increase in the electroneutral component of Ca flux rates from the mucosal to the serosal side of rumen epithelium. As plasma calcitriol concentrations were not affected, it can be concluded that the administration of anionic salts results in a vitamin D-independent stimulation of ruminal Ca transport. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

Selenium speciation in seleniferous agricultural soils under different cropping systems using sequential extraction and X-ray absorption spectroscopy.

PubMed

Qin, Hai-Bo; Zhu, Jian-Ming; Lin, Zhi-Qing; Xu, Wen-Po; Tan, De-Can; Zheng, Li-Rong; Takahashi, Yoshio

2017-06-01

Selenium (Se) speciation in soil is critically important for understanding the solubility, mobility, bioavailability, and toxicity of Se in the environment. In this study, Se fractionation and chemical speciation in agricultural soils from seleniferous areas were investigated using the elaborate sequential extraction and X-ray absorption near-edge structure (XANES) spectroscopy. The speciation results quantified by XANES technique generally agreed with those obtained by sequential extraction, and the combination of both approaches can reliably characterize Se speciation in soils. Results showed that dominant organic Se (56-81% of the total Se) and lesser Se(IV) (19-44%) were observed in seleniferous agricultural soils. A significant decrease in the proportion of organic Se to the total Se was found in different types of soil, i.e., paddy soil (81%) > uncultivated soil (69-73%) > upland soil (56-63%), while that of Se(IV) presented an inverse tendency. This suggests that Se speciation in agricultural soils can be significantly influenced by different cropping systems. Organic Se in seleniferous agricultural soils was probably derived from plant litter, which provides a significant insight for phytoremediation in Se-laden ecosystems and biofortification in Se-deficient areas. Furthermore, elevated organic Se in soils could result in higher Se accumulation in crops and further potential chronic Se toxicity to local residents in seleniferous areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electron localization and optical absorption of polygonal quantum rings

NASA Astrophysics Data System (ADS)

Sitek, Anna; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2015-06-01

We investigate theoretically polygonal quantum rings and focus mostly on the triangular geometry where the corner effects are maximal. Such rings can be seen as short core-shell nanowires, a generation of semiconductor heterostructures with multiple applications. We show how the geometry of the sample determines the electronic energy spectrum, and also the localization of electrons, with effects on the optical absorption. In particular, we show that irrespective of the ring shape low-energy electrons are always attracted by corners and are localized in their vicinity. The absorption spectrum in the presence of a magnetic field shows only two peaks within the corner-localized state domain, each associated with different circular polarization. This picture may be changed by an external electric field which allows previously forbidden transitions, and thus enables the number of corners to be determined. We show that polygonal quantum rings allow absorption of waves from distant ranges of the electromagnetic spectrum within one sample.

The Impact of Sex Differences on Odor Identification and Facial Affect Recognition in Patients with Schizophrenia Spectrum Disorders.

PubMed

Mossaheb, Nilufar; Kaufmann, Rainer M; Schlögelhofer, Monika; Aninilkumparambil, Thushara; Himmelbauer, Claudia; Gold, Anna; Zehetmayer, Sonja; Hoffmann, Holger; Traue, Harald C; Aschauer, Harald

2018-01-01

Social interactive functions such as facial emotion recognition and smell identification have been shown to differ between women and men. However, little is known about how these differences are mirrored in patients with schizophrenia and how these abilities interact with each other and with other clinical variables in patients vs. healthy controls. Standardized instruments were used to assess facial emotion recognition [Facially Expressed Emotion Labelling (FEEL)] and smell identification [University of Pennsylvania Smell Identification Test (UPSIT)] in 51 patients with schizophrenia spectrum disorders and 79 healthy controls; furthermore, working memory functions and clinical variables were assessed. In both the univariate and the multivariate results, illness showed a significant influence on UPSIT and FEEL. The inclusion of age and working memory in the MANOVA resulted in a differential effect with sex and working memory as remaining significant factors. Duration of illness was correlated with both emotion recognition and smell identification in men only, whereas immediate general psychopathology and negative symptoms were associated with emotion recognition only in women. Being affected by schizophrenia spectrum disorder impacts one's ability to correctly recognize facial affects and identify odors. Converging evidence suggests a link between the investigated basic and social cognitive abilities in patients with schizophrenia spectrum disorders with a strong contribution of working memory and differential effects of modulators in women vs. men.

The X-ray absorption spectrum of 4U1700-37 and its implications for the stellar wind of the companion HD153919

NASA Technical Reports Server (NTRS)

White, N. E.; Kallman, T. R.; Swank, J. H.

1982-01-01

The first high resolution non-dispersive 2-60 KeV X-ray spectra of 4U1700-37 is presented. The continuum is typical of that found from X-ray pulsars; that is a flat power law between 2 and 10 keV and, beyond 10 keV, an exponential decay of characteristic energy varying between 10 and 20 keV. No X-ray pulsations were detected between 160 ms and 6 min with an amplitude greater than approximately 2%. The absorption measured at binary phases approximately 0.72 is comparable to that expected from the stellar wind of the primary. The gravitational capture of material in the wind is found to be more than enough to power the X-ray source. The increase in the average absorption after phi o approximately 0.5 is confirmed. The minimum level of adsorption is a factor of 2 or 3 lower than that reported by previous observers, which may be related to a factor of approximately 10 decline in the average X-ray luminosity over the same interval. Short term approximately 50% variations in adsorption are seen for the first time which appear to be loosely correlated with approximately 10 min flickering activity in the X-ray flux. These most likely originate from inhomogeneities in the stellar wind of the primary.

Ab-initio study on the absorption spectrum of color change sapphire based on first-principles calculations with considering lattice relaxation-effect

NASA Astrophysics Data System (ADS)

Novita, Mega; Nagoshi, Hikari; Sudo, Akiho; Ogasawara, Kazuyoshi

2018-01-01

In this study, we performed an investigation on α-Al2O3: V3+ material, or the so-called color change sapphire, based on first-principles calculations without referring to any experimental parameter. The molecular orbital (MO) structure was estimated by the one-electron MO calculations using the discrete variational-Xα (DV-Xα) method. Next, the absorption spectra were estimated by the many-electron calculations using the discrete variational multi-electron (DVME) method. The effect of lattice relaxation on the crystal structures was estimated based on the first-principles band structure calculations. We performed geometry optimizations on the pure α-Al2O3 and with the impurity V3+ ion using Cambridge Serial Total Energy Package (CASTEP) code. The effect of energy corrections such as configuration dependence correction and correlation correction was also investigated in detail. The results revealed that the structural change on the α-Al2O3: V3+ resulted from the geometry optimization improved the calculated absorption spectra. By a combination of both the lattice relaxation-effect and the energy correction-effect improve the agreement to the experiment fact.

All-particle energy spectrum of KASCADE-Grande based on shower size and different hadronic interaction models

NASA Astrophysics Data System (ADS)

Kang, D.; Apel, W. D.; Arteaga-Velazquez, J. C.; Bekk, K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Engler, J.; Finger, M.; Fuchs, B.; Fuhrmann, D.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Huber, D.; Huege, T.; Kampert, K.-H.; Klages, H. O.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Mayer, H. J.; Melissas, M.; Milke, J.; Morello, C.; Oehlschläger, J.; Ostapchenko, S.; Palmieri, N.; Petcu, M.; Pierog, T.; Rebel, H.; Roth, M.; Schieler, H.; Schoo, S.; Schroder, F.; Sima, O.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.

2013-02-01

KASCADE-Grande is a large detector array for observations of the energy spectrum as well as the chemical composition of cosmic ray air showers up to primary energies of 1 EeV. The multi-detector arrangement allows to measure the electromagnetic and muonic components for individual air showers. In this analysis, the reconstruction of the all-particle energy spectrum is based on the size spectra of the charged particle component. The energy is calibrated by using Monte Carlo simulations performed with CORSIKA and high-energy interaction models QGSJet, EPOS and SIBYLL. In all cases FLUKA has been used as low-energy interaction model. In this contribution the resulting spectra by means of different hadronic interaction models will be compared and discussed.

Cortisol Responsivity Differences in Children with Autism Spectrum Disorders During Free and Cooperative Play

PubMed Central

Schupp, Clayton; Simon, David; Corbett, Blythe A.

2013-01-01

Children with ASD demonstrate significant heterogeneity in their profiles of social interaction and stress responsivity. We evaluated behavior and stress response in 52 male children ages 8 to 12 in a naturalistic playground interaction paradigm involving a child with autism spectrum disorder, a typically developing peer, and a same-age confederate. Younger children in the ASD group engaged in 5.8 times more approach behavior and showed a lower cortisol response than their older peers. Those that verbally initiated with their peers also showed a higher cortisol response. Older children with ASD exhibited the highest stress responsivity, while younger children with ASD showed more willingness to approach others without apparent stress. Intervening early and often may contribute to improvements in social engagement in youth with ASD. PMID:23430177

Communication: THz absorption spectrum of the CO2-H2O complex: observation and assignment of intermolecular van der Waals vibrations.

PubMed

Andersen, J; Heimdal, J; Mahler, D W; Nelander, B; Larsen, R Wugt

2014-03-07

Terahertz absorption spectra have been recorded for the weakly bound CO2-H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems' flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm(-1) from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm(-1) for the dissociation energy D0.

The impact of different multi-walled carbon nanotubes on the X-band microwave absorption of their epoxy nanocomposites.

PubMed

Che, Bien Dong; Nguyen, Bao Quoc; Nguyen, Le-Thu T; Nguyen, Ha Tran; Nguyen, Viet Quoc; Van Le, Thang; Nguyen, Nieu Huu

2015-01-01

Carbon nanotube (CNT) characteristics, besides the processing conditions, can change significantly the microwave absorption behavior of CNT/polymer composites. In this study, we investigated the influence of three commercial multi-walled CNT materials with various diameters and length-to-diameter aspect ratios on the X-band microwave absorption of epoxy nanocomposites with CNT contents from 0.125 to 2 wt%, prepared by two dispersion methods, i.e. in solution with surfactant-aiding and via ball-milling. The laser diffraction particle size and TEM analysis showed that both methods produced good dispersions at the microscopic level of CNTs. Both a high aspect ratio resulting in nanotube alignment trend and good infiltration of the matrix in the individual nanotubes, which was indicated by high Brookfield viscosities at low CNT contents of CNT/epoxy dispersions, are important factors to achieve composites with high microwave absorption characteristics. The multi-walled carbon nanotube (MWCNT) with the largest aspect ratio resulted in composites with the best X-band microwave absorption performance, which is considerably better than that of reported pristine CNT/polymer composites with similar or lower thicknesses and CNT loadings below 4 wt%. A high aspect ratio of CNTs resulting in microscopic alignment trend of nanotubes as well as a good level of micro-scale CNT dispersion resulting from good CNT-matrix interactions are crucial to obtain effective microwave absorption performance. This study demonstrated that effective radar absorbing MWCNT/epoxy nanocomposites having small matching thicknesses of 2-3 mm and very low filler contents of 0.25-0.5 wt%, with microwave energy absorption in the X-band region above 90% and maximum absorption peak values above 97%, could be obtained via simple processing methods, which is promising for mass production in industrial applications. Graphical AbstractComparison of the X-band microwave reflection loss of epoxy composites of

Discrimination of Gastrodia elata from Different Geographical Origin for Quality Evaluation Using Newly-Build Near Infrared Spectrum Coupled with Multivariate Analysis.

PubMed

Zuo, Yamin; Deng, Xuehua; Wu, Qing

2018-05-04

Discrimination of Gastrodia elata ( G. elata ) geographical origin is of great importance to pharmaceutical companies and consumers in China. this paper focuses on the feasibility of near infrared spectrum (NIRS) combined multivariate analysis as a rapid and non-destructive method to prove its fit for this purpose. Firstly, 16 batches of G. elata samples from four main-cultivation regions in China were quantified by traditional HPLC method. It showed that samples from different origins could not be efficiently differentiated by the contents of four phenolic compounds in this study. Secondly, the raw near infrared (NIR) spectra of those samples were acquired and two different pattern recognition techniques were used to classify the geographical origins. The results showed that with spectral transformation optimized, discriminant analysis (DA) provided 97% and 99% correct classification for the calibration and validation sets of samples from discriminating of four different main-cultivation regions, and provided 98% and 99% correct classifications for the calibration and validation sets of samples from eight different cities, respectively, which all performed better than the principal component analysis (PCA) method. Thirdly, as phenolic compounds content (PCC) is highly related with the quality of G. elata , synergy interval partial least squares (Si-PLS) was applied to build the PCC prediction model. The coefficient of determination for prediction (R p ²) of the Si-PLS model was 0.9209, and root mean square error for prediction (RMSEP) was 0.338. The two regions (4800 cm −1 ⁻5200 cm −1 , and 5600 cm −1 ⁻6000 cm −1 ) selected by Si-PLS corresponded to the absorptions of aromatic ring in the basic phenolic structure. It can be concluded that NIR spectroscopy combined with PCA, DA and Si-PLS would be a potential tool to provide a reference for the quality control of G. elata.

No differences in emotion recognition strategies in children with autism spectrum disorder: evidence from hybrid faces.

PubMed

Evers, Kris; Kerkhof, Inneke; Steyaert, Jean; Noens, Ilse; Wagemans, Johan

2014-01-01

Emotion recognition problems are frequently reported in individuals with an autism spectrum disorder (ASD). However, this research area is characterized by inconsistent findings, with atypical emotion processing strategies possibly contributing to existing contradictions. In addition, an attenuated saliency of the eyes region is often demonstrated in ASD during face identity processing. We wanted to compare reliance on mouth versus eyes information in children with and without ASD, using hybrid facial expressions. A group of six-to-eight-year-old boys with ASD and an age- and intelligence-matched typically developing (TD) group without intellectual disability performed an emotion labelling task with hybrid facial expressions. Five static expressions were used: one neutral expression and four emotional expressions, namely, anger, fear, happiness, and sadness. Hybrid faces were created, consisting of an emotional face half (upper or lower face region) with the other face half showing a neutral expression. Results showed no emotion recognition problem in ASD. Moreover, we provided evidence for the existence of top- and bottom-emotions in children: correct identification of expressions mainly depends on information in the eyes (so-called top-emotions: happiness) or in the mouth region (so-called bottom-emotions: sadness, anger, and fear). No stronger reliance on mouth information was found in children with ASD.

Different Aberrant Mentalizing Networks in Males and Females with Autism Spectrum Disorders: Evidence from Resting-State Functional Magnetic Resonance Imaging

ERIC Educational Resources Information Center

Yang, Jie; Lee, Jonathan

2018-01-01

Previous studies have found that individuals with autism spectrum disorders show impairments in mentalizing processes and aberrant brain activity compared with typically developing participants. However, the findings are mainly from male participants and the aberrant effects in autism spectrum disorder females and sex differences are still…

Examination of Sex Differences in a Large Sample of Young Children with Autism Spectrum Disorder and Typical Development

PubMed Central

Reinhardt, Vanessa P.; Wetherby, Amy M.; Schatschneider, Christopher

2014-01-01

Despite consistent and substantive research documenting a large male to female ratio in Autism Spectrum Disorder (ASD), only a modest body of research exists examining sex differences in characteristics. This study examined sex differences in developmental functioning and early social communication in children with ASD as compared to children with typical development. Sex differences in adaptive behavior and autism symptoms were also examined in children with ASD. Participants (n = 511) were recruited from the Florida State University FIRST WORDS® Project and University of Michigan Autism and Communication Disorders Center. Analyses did not reveal significant effects of sex or a diagnostic group by sex interaction, suggesting a similar phenotype in males and females early in development. Further research is needed to examine sex differences across development. PMID:25189824

Sex and gender differences in autism spectrum disorder: summarizing evidence gaps and identifying emerging areas of priority.

PubMed

Halladay, Alycia K; Bishop, Somer; Constantino, John N; Daniels, Amy M; Koenig, Katheen; Palmer, Kate; Messinger, Daniel; Pelphrey, Kevin; Sanders, Stephan J; Singer, Alison Tepper; Taylor, Julie Lounds; Szatmari, Peter

2015-01-01

One of the most consistent findings in autism spectrum disorder (ASD) research is a higher rate of ASD diagnosis in males than females. Despite this, remarkably little research has focused on the reasons for this disparity. Better understanding of this sex difference could lead to major advancements in the prevention or treatment of ASD in both males and females. In October of 2014, Autism Speaks and the Autism Science Foundation co-organized a meeting that brought together almost 60 clinicians, researchers, parents, and self-identified autistic individuals. Discussion at the meeting is summarized here with recommendations on directions of future research endeavors.

Sex/Gender Differences in Screening for Autism Spectrum Disorder: Implications for Evidence-Based Assessment.

PubMed

Evans, Spencer C; Boan, Andrea D; Bradley, Catherine; Carpenter, Laura A

2018-03-30

Autism spectrum disorder (ASD) is diagnosed more often in boys than in girls; however, little is known about the nature of this sex/gender discrepancy or how it relates to diagnostic assessment practices. This study examined the performance of the Social Communication Questionnaire (SCQ) in screening for ASD among boys and girls. Data were drawn from the South Carolina Children's Educational Surveillance Study, a population-based study of ASD prevalence among children 8-10 years of age. Analyses were conducted using SCQ data from 3,520 children, with direct assessment data from 272 with elevated SCQ scores. A bifactor model based on the Diagnostic and Statistical Manual of Mental Disorders's (5th ed.) two ASD symptom domains fit the data well and performed slightly better for girls. In the general population sample, girls exhibited fewer social communication/interaction and restricted-repetitive behavior symptoms than boys. In the direct assessment sample, however, girls with ASD showed greater impairment in social communication/interaction than boys with ASD. Items pertaining to social communication/interaction problems at ages 4-5 were among the most diagnostically efficient overall and particularly for girls. Similarly, receiver operating characteristic analyses suggested that the SCQ performs adequately among boys and well among girls. Results support the use of the SCQ in screening for ASD but do not indicate sex/gender-specific cutoffs. Girls with ASD may exhibit pronounced intraindividual deficits in social communication/interaction compared to male peers with ASD and female peers without ASD. Although more research is needed, careful attention to social communication/interaction deficits around 4-5 years of age may be especially useful for assessing ASD in girls.

Prevalence of SHANK3 variants in patients with different subtypes of autism spectrum disorders.

PubMed

Boccuto, Luigi; Lauri, Maria; Sarasua, Sara M; Skinner, Cindy D; Buccella, Daniela; Dwivedi, Alka; Orteschi, Daniela; Collins, Julianne S; Zollino, Marcella; Visconti, Paola; Dupont, Barb; Tiziano, Danilo; Schroer, Richard J; Neri, Giovanni; Stevenson, Roger E; Gurrieri, Fiorella; Schwartz, Charles E

2013-03-01

Autism spectrum disorders (ASDs) include three main conditions: autistic disorder (AD), pervasive developmental disorder, not otherwise specified (PDD-NOS), and Asperger syndrome. It has been shown that many genes associated with ASDs are involved in the neuroligin-neurexin interaction at the glutamate synapse: NLGN3, NLGN4, NRXN1, CNTNAP2, and SHANK3. We screened this last gene in two cohorts of ASD patients (133 patients from US and 88 from Italy). We found 5/221 (2.3%) cases with pathogenic alterations: a 106 kb deletion encompassing the SHANK3 gene, two frameshift mutations leading to premature stop codons, a missense mutation (p.Pro141Ala), and a splicing mutation (c.1820-4 G>A). Additionally, in 17 patients (7.7%) we detected a c.1304+48C>T transition affecting a methylated cytosine in a CpG island. This variant is reported as SNP rs76224556 and was found in both US and Italian controls, but it results significantly more frequent in our cases than in the control cohorts. The variant is also significantly more common among PDD-NOS cases than in AD cases. We also screened this gene in an independent replication cohort of 104 US patients with ASDs, in which we found a missense mutation (p.Ala1468Ser) in 1 patient (0.9%), and in 8 patients (7.7%) we detected the c.1304+48C>T transition. While SHANK3 variants are present in any ASD subtype, the SNP rs76224556 appears to be significantly associated with PDD-NOS cases. This represents the first evidence of a genotype-phenotype correlation in ASDs and highlights the importance of a detailed clinical-neuropsychiatric evaluation for the effective genetic screening of ASD patients.

Prevalence of SHANK3 variants in patients with different subtypes of autism spectrum disorders

PubMed Central

Boccuto, Luigi; Lauri, Maria; Sarasua, Sara M; Skinner, Cindy D; Buccella, Daniela; Dwivedi, Alka; Orteschi, Daniela; Collins, Julianne S; Zollino, Marcella; Visconti, Paola; DuPont, Barb; Tiziano, Danilo; Schroer, Richard J; Neri, Giovanni; Stevenson, Roger E; Gurrieri, Fiorella; Schwartz, Charles E

2013-01-01

Autism spectrum disorders (ASDs) include three main conditions: autistic disorder (AD), pervasive developmental disorder, not otherwise specified (PDD-NOS), and Asperger syndrome. It has been shown that many genes associated with ASDs are involved in the neuroligin–neurexin interaction at the glutamate synapse: NLGN3, NLGN4, NRXN1, CNTNAP2, and SHANK3. We screened this last gene in two cohorts of ASD patients (133 patients from US and 88 from Italy). We found 5/221 (2.3%) cases with pathogenic alterations: a 106 kb deletion encompassing the SHANK3 gene, two frameshift mutations leading to premature stop codons, a missense mutation (p.Pro141Ala), and a splicing mutation (c.1820-4 G>A). Additionally, in 17 patients (7.7%) we detected a c.1304+48C>T transition affecting a methylated cytosine in a CpG island. This variant is reported as SNP rs76224556 and was found in both US and Italian controls, but it results significantly more frequent in our cases than in the control cohorts. The variant is also significantly more common among PDD-NOS cases than in AD cases. We also screened this gene in an independent replication cohort of 104 US patients with ASDs, in which we found a missense mutation (p.Ala1468Ser) in 1 patient (0.9%), and in 8 patients (7.7%) we detected the c.1304+48C>T transition. While SHANK3 variants are present in any ASD subtype, the SNP rs76224556 appears to be significantly associated with PDD-NOS cases. This represents the first evidence of a genotype–phenotype correlation in ASDs and highlights the importance of a detailed clinical-neuropsychiatric evaluation for the effective genetic screening of ASD patients. PMID:22892527

Intestinal absorption differences of major bioactive compounds of Gegenqinlian Decoction between normal and bacterial diarrheal mini-pigs in vitro and in situ.

PubMed

Ling, Xiao; Xiang, Yuqiang; Chen, Feilong; Tang, Qingfa; Zhang, Wei; Tan, Xiaomei

2018-04-15

Intestinal condition plays an important role in drug absorption and metabolism, thus the effects of varied gastrointestinal diseases such as infectious diarrhea on the intestinal function are crucial for drug absorption. However, due to the lack of suitable models, the differences of absorption and metabolism of drugs between the diarrheal and normal intestines are rarely reported. Thus, in this study, Escherichia coli diarrhea model was induced in mini-pigs and single-pass intestinal perfusion and intestinal mucosal enzyme metabolism experiments were conducted. A simple and rapid ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to determine the concentrations of 9 major components in Gegen Qinlian decoction (GQD). Samples were pretreated by protein precipitation with methanol and naringin and prednisolone were used as internal standards. The validated method demonstrated adequate sensitivity, selectivity, and process efficiency for the bioanalysis of 9 compounds. Results of intestinal perfusion showed that puerarin, daidzein, daidzin and baicalin and berberine were absorbed faster in diarrheal jejunum than in normal intestines (p < 0.05). However, puerarin, daidzin and liquiritin were metabolized more slowly in diarrheal intestine after incubation compared with the normal group (p < 0.05). The concentrations of daidzein in both perfusion and metabolism and wogonin in metabolism were significantly increased (p < 0.05). In conclusion, absorption and metabolism of GQD were significantly different between the diarrheal and normal intestines, which suggest that bacterial diarrheal mini-pigs model can be used in the intestinal absorption study and is worthy to be applied in the other intestinal absorption study of anti- diarrheal drugs. Copyright © 2018 Elsevier B.V. All rights reserved.

Spatial-frequency spectrum of patterns changes the visibility of spatial-phase differences

NASA Technical Reports Server (NTRS)

Lawton, T. B.

1985-01-01

It is shown that spatial-frequency components over a 4-octave range affected the visibility of spatial-phase differences. Contrast thresholds were measured for discrimination between two (+45- and -45-deg) spatial phases of a sinusoidal test grating added to a background grating. The background could contain one or several sinusoidal components, all in 0-deg phase. Phase differences between the test and the background were visible at lower contrasts when test and background frequencies were harmonically related than when they were not, when test and background frequencies were within 1 octave than when they were farther apart, when the fundamental frequency of the background was low than when it was high, and for some discriminations more than for others, after practice. The visibility of phase differences was not affected by additional components in the background if the fundamental and difference frequencies of the background remained unchanged. Observers' reports of their strategies gave information about the types of attentive processing that were used to discriminate phase differences. Attentive processing facilitated phase discrimination for multifrequency gratings spanning a much wider range of spatial frequencies than would be possible by using only local preattentive processing. These results were consistent with the visibility of phase differences being processed by some combination of even- and odd-symmetric simple cells tuned to a wide range of different spatial frequencies.

Quantification of the power changes in BOLD signals using Welch spectrum method during different single-hand motor imageries.

PubMed

Zhang, Jiang; Yuan, Zhen; Huang, Jin; Yang, Qin; Chen, Huafu

2014-12-01

Motor imagery is an experimental paradigm implemented in cognitive neuroscience and cognitive psychology. To investigate the asymmetry of the strength of cortical functional activity due to different single-hand motor imageries, functional magnetic resonance imaging (fMRI) data from right handed normal subjects were recorded and analyzed during both left-hand and right-hand motor imagery processes. Then the average power of blood oxygenation level-dependent (BOLD) signals in temporal domain was calculated using the developed tool that combines Welch power spectrum and the integral of power spectrum approach of BOLD signal changes during motor imagery. Power change analysis results indicated that cortical activity exhibited a stronger power in the precentral gyrus and medial frontal gyrus with left-hand motor imagery tasks compared with that from right-hand motor imagery tasks. These observations suggest that right handed normal subjects mobilize more cortical nerve cells for left-hand motor imagery. Our findings also suggest that the approach based on power differences of BOLD signals is a suitable quantitative analysis tool for quantification of asymmetry of brain activity intensity during motor imagery tasks. Copyright © 2014 Elsevier Inc. All rights reserved.

Ly α Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions

SciTech Connect

Khodachenko, M. L.; Lammer, H.; Kislyakova, K. G.

To shed more light on the nature of the observed Ly α absorption during transits of HD 209458b and to quantify the major mechanisms responsible for the production of fast hydrogen atoms (the so-called energetic neutral atoms, ENAs) around the planet, 2D hydrodynamic multifluid modeling of the expanding planetary upper atmosphere, which is driven by stellar XUV, and its interaction with the stellar wind has been performed. The model self-consistently describes the escaping planetary wind, taking into account the generation of ENAs due to particle acceleration by the radiation pressure and by the charge exchange between the stellar wind protonsmore » and planetary atoms. The calculations in a wide range of stellar wind parameters and XUV flux values showed that under typical Sun-like star conditions, the amount of generated ENAs is too small, and the observed absorption at the level of 6%–8% can be attributed only to the non-resonant natural line broadening. For lower XUV fluxes, e.g., during the activity minima, the number of planetary atoms that survive photoionization and give rise to ENAs increases, resulting in up to 10%–15% absorption at the blue wing of the Ly α line, caused by resonant thermal line broadening. A similar asymmetric absorption can be seen under the conditions realized during coronal mass ejections, when sufficiently high stellar wind pressure confines the escaping planetary material within a kind of bowshock around the planet. It was found that the radiation pressure in all considered cases has a negligible contribution to the production of ENAs and the corresponding absorption.« less

[Analysis of different health status based on characteristics of the facial spectrum photometric color].

PubMed

Xu, Jiatuo; Wu, Hongjin; Lu, Luming; Tu, Liping; Zhang, Zhifeng; Chen, Xiao

2012-12-01

This paper is aimed to observe the difference of facial color of people with different health status by spectral photometric color measuring technique according to the theory of facial color diagnosis in Internal Classic. We gathered the facial color information about the health status of persons in healthy group (183), sub-healthy group (287) and disease group (370) respectively. The information included L, a, b, C values and reflection of different wavelengths in 400-700nm with CM-2600D spectral photometric color measuring instrument on 8 points. The results indicated that overall complexion color values of the people in the three groups were significantly different. The persons in the disease group looked deep dark in features. The people in the sub-healthy group looked pale in features. The loci L, a, b, C values were with varying degrees of significant differences (P < 0.05) at 6 points among the groups, and the central position of the face in all the groups was the position with most significant differences. Comparing the facial color information at the same point of the people in the three groups, we obtained each group's diagnostic special point. There existed diagnostic values in distinguishing disease status and various status of health in some degree by spectral photometric color measuring technique. The present method provides a prosperous quantitative basis for Chinese medical inspection of the complexion diagnosis.

A Review of the Differences in Developmental, Psychiatric, and Medical Endophenotypes Between Males and Females with Autism Spectrum Disorder

PubMed Central

Rubenstein, Eric; Wiggins, Lisa D.; Lee, Li-Ching

2015-01-01

Autism spectrum disorder (ASD) is over four times more prevalent in males compared to females. Increased understanding of sex differences in ASD endophenotypes could add insight into possible etiologies and the assessment and management of the disorder. Consequently, the purpose of this review is to describe current literature regarding sex differences in the developmental, psychiatric, and medical endophenotypes of ASD in order to illustrate current knowledge and areas in need of further research. Our review found that repetitive behaviors and restricted interests are more common in males than females with ASD. Intellectual disability is more common in females than males with ASD. Attention to detail may be more common in males than females with ASD and epilepsy may be more common in females than males with ASD, although limited research in these areas prevent definitive conclusions from being drawn. There does not appear to be a sex difference in other developmental, psychiatric, and medical symptoms associated with ASD, or the research was contradictory or too sparse to establish a sex difference. Our review is unique in that it offers detailed discussion of sex differences in three major endophenotypes of ASD. Further research is needed to better understand why sex differences exist in certain ASD traits and to evaluate whether phenotypic sex differences are related to different pathways of development, assessment, and treatment of the disorder. PMID:26146472

Narratives of Girls and Boys with Autism Spectrum Disorders: Gender Differences in Narrative Competence and Internal State Language.

PubMed

Kauschke, Christina; van der Beek, Bettina; Kamp-Becker, Inge

2016-03-01

Since gender differences in the symptomatology of autism spectrum disorder (ASD) are not well understood, the current study examines the communicative skills of males and females with ASD. Narrative competence and internal state language (ISL) was investigated using narrations elicited by a wordless picture book. 11 girls and 11 boys with ASD and 11 typically developing girls were individually matched. Although results demonstrate largely comparable narrative skills across groups, the groups differed with respect to the size and use of ISL: Girls with ASD verbalized and motivated internal states more often than boys, and both groups with ASD fell behind typically developing children in production of affective words. Implications for the clinical presentation of males and females with ASD are discussed.

Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head

PubMed Central

Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Amirhajeloo, Leila Rasouli; Mirzaei, Maryam

2016-01-01

The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m and 2.23±0.39 v/m, respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23% and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart mobile phones at the frequencies of 900 and 1800 MHz was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone. PMID:27157169

Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head.

PubMed

Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Rasouli Amirhajeloo, Leila; Mirzaei, Maryam

2016-09-01

The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m  and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart  mobile phones at the frequencies of 900 and 1800 MHz  was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone.

Testing the performance of pure spectrum resolution from Raman hyperspectral images of differently manufactured pharmaceutical tablets.

PubMed

Vajna, Balázs; Farkas, Attila; Pataki, Hajnalka; Zsigmond, Zsolt; Igricz, Tamás; Marosi, György

2012-01-27

Chemical imaging is a rapidly emerging analytical method in pharmaceutical technology. Due to the numerous chemometric solutions available, characterization of pharmaceutical samples with unknown components present has also become possible. This study compares the performance of current state-of-the-art curve resolution methods (multivariate curve resolution-alternating least squares, positive matrix factorization, simplex identification via split augmented Lagrangian and self-modelling mixture analysis) in the estimation of pure component spectra from Raman maps of differently manufactured pharmaceutical tablets. The batches of different technologies differ in the homogeneity level of the active ingredient, thus, the curve resolution methods are tested under different conditions. An empirical approach is shown to determine the number of components present in a sample. The chemometric algorithms are compared regarding the number of detected components, the quality of the resolved spectra and the accuracy of scores (spectral concentrations) compared to those calculated with classical least squares, using the true pure component (reference) spectra. It is demonstrated that using appropriate multivariate methods, Raman chemical imaging can be a useful tool in the non-invasive characterization of unknown (e.g. illegal or counterfeit) pharmaceutical products. Copyright © 2011 Elsevier B.V. All rights reserved.

Spectrum of gross motor and cognitive functions in children with cerebral palsy: gender differences.

PubMed

Romeo, Domenico M M; Cioni, Matteo; Battaglia, Laura R; Palermo, Filippo; Mazzone, Domenico

2011-01-01

Multiple differences between males and females are reported both in physiological and pathophysiological conditions. To test the hypothesis that gender could influence the motor and cognitive development in children with cerebral palsy (CP). Prospective, cross-sectional. One hundred seventy one children with CP (98 males and 73 females) were evaluated for motor (Gross Motor Function Measure, Gross Motor Function Classification System) and cognitive (Bayley II, Wechsler Scales) functions. Eighty-four of them were assessed before and other eighty-seven children after 4 years of age. No gender-related differences were observed in children with diplegia or quadriplegia, both for motor and cognitive functions. On the contrary, females with hemiplegia scored significantly better (P < 0.01) in cognitive functions and in the dimension D (standing) of the Gross Motor Function Measure, under the age of 4 years. These differences were not observed after this age. In this study we point out that gender might influence differently the psycho-motor development of children with hemiplegia and of those with a more severe clinical involvement as diplegia and quadriplegia. © 2010 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Does the clinical spectrum of incident cardiovascular disease differ between men and women?

PubMed

Lehto, Hanna-Riikka; Lehto, Seppo; Havulinna, Aki S; Salomaa, Veikko

2014-08-01

Cardiovascular diseases (CVDs) are the main cause of death and disability in the western world. Women are known to be older at the time of first CVD event, but the main types of CVD events and their relative importance and differences compared with men are not well known. Our aim was to evaluate gender differences in the clinical presentation of incident major adverse cardiovascular events (MACE). A population-based study with prospective follow-up. We used data from the population-based National FINRISK Surveys from years 1992, 1997, 2002 and 2007. People with prevalent cardiovascular disease were excluded. In total, 27,897 participants (53, 2% women) aged 25-74 years were included in the analyses. During the 292,316 person-years of follow-up, 2573 MACE were identified. MACE were more frequent in men than women (1318; 95% CI 1252-1388 in men vs. 736; 686-789 in women). Men had four times more fatal coronary heart disease (CHD) events (149; 126-174 vs. 39; 28-53) and three times more non-fatal CHD events (512; 471-555 vs. 164; 141-189) than women. Stroke incidence was higher in men than women (268; 238-301 vs. 169; 145-195). Heart failure (HF) incidence did not differ between genders. The relative proportions of MACE categories differed substantially between genders: HF was the most common type among women (50% vs. 30% in men), whereas the most common type among men was CHD (50% vs. 28% in women). Incident MACE were more common in men than women. HF was the dominant type of MACE in women, whereas CHD dominated in men. © The European Society of Cardiology 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Frequency spectrum of transepithelial potential difference reveals transport-related oscillations.

PubMed

Montalbetti, Nicolás; Fischbarg, Jorge

2009-09-16

How epithelia transport fluid is a fundamental issue that is unresolved. Explanations offered include molecular engines, local transcellular osmosis, local paracellular osmosis, and paracellular fluid transport. On the basis of experimental and theoretical work done on corneal endothelium, a fluid transporting epithelium, we suggest electroosmotic coupling at the level of the intercellular junctions driven by the transendothelial electrical potential difference as an explanation of paracellular fluid transport. We collect frequency spectra of that potential difference in real-time. For what we believe is the first time for any epithelium, we report that, unexpectedly, the potential difference displays oscillations at many characteristic frequencies. We also show that on both stimulating cell activity and inhibiting ion transport mechanisms, there are corresponding changes in the oscillations amplitudes that mirror changes known previously in rates of fluid transport. We believe these findings provide a novel tool to study the kinetics of electrogenic elements such as channels and transporters, which from this evidence would give rise to current oscillations with characteristic periods going from 150 ms to 8 s.

A study of structural differences between TBM patients' and non-TBM persons' CSF using UV-Vis absorption spectroscopy

NASA Astrophysics Data System (ADS)

Xu, Fangcheng; Wang, Xin; Xu, Huajia; Wang, Kai

2016-01-01

Tuberculous meningitis (TBM) is a very common infectious disease in the central nervous system. The delay of diagnosing and treating TBM will lead to high disability and mortality of TBM. Hence, it is very important to promptly diagnose TBM early. In this work, we proposed a new method for diagnosing TBM with CSF samples by using UV-Vis absorption spectroscopy. CSF samples from TBM patients and non-TBM persons were compared, and the sensitivity, specificity, accuracy, positive predictive value reached 83.6%, 69.8%, 77.2%, 76.1% respectively. Our work indicated investigation of CSF using UV-Vis absorption spectroscopy might become a potentially useful method for TBM diagnosis.

Matrix effects on the determination of manganese in geological materials by atomic-absorption spectrophotometry under different flame conditions

USGS Publications Warehouse

Sanzolone, R.F.; Chao, T.T.

1978-01-01

Suppression caused by five of the seven matrix elements studied (Si, Al, Fe, Ca and Mg) was observed in the atomic-absorption determination of manganese in geological materials, when synthetic solutions and the recommended oxidizing air-acetylene flame were used. The magnitude of the suppression effects depends on (1) the kind and concentration of the interfering elements, (2) the type of acid medium, and (3) the concentration of manganese to be determined. All interferences noted are removed or alleviated by using a reducing nitrous oxide-acetylene flame. The atomic-absorption method using this flame can be applied to the determination of total and extractable manganese in a wide range of geological materials without interferences. Analyses of six U.S. Geological Survey rock standards for manganese gave results in agreement with the reported values. ?? 1978.

Finding consistency between different views of the absorption enhancement of black carbon: An observationally constrained hybrid model to support a transition in optical properties with mass fraction

NASA Astrophysics Data System (ADS)

Coe, H.; Allan, J. D.; Whitehead, J.; Alfarra, M. R. R.; Villegas, E.; Kong, S.; Williams, P. I.; Ting, Y. C.; Haslett, S.; Taylor, J.; Morgan, W.; McFiggans, G.; Spracklen, D. V.; Reddington, C.

2015-12-01

The mixing state of black carbon is uncertain yet has a significant influence on the efficiency with which a particle absorbs light. In turn, this may make a significant contribution to the uncertainty in global model predictions of the black carbon radiative budget. Previous modelling studies that have represented this mixing state using a core-shell approach have shown that aged black carbon particles may be considerably enhanced compared to freshly emitted black carbon due to the addition of co-emitted, weakly absorbing species. However, recent field results have demonstrated that any enhancement of absorption is minor in the ambient atmosphere. Resolving these differences in absorption efficiency is important as they will have a major impact on the extent to which black carbon heats the atmospheric column. We have made morphology-independent measurements of refractory black carbon mass and associated weakly absorbing material in single particles from laboratory-generated diesel soot and black carbon particles in ambient air influenced by traffic and wood burning sources and related these to the optical properties of the particles. We compared our calculated optical properties with optical models that use varying mixing state assumptions and by characterising the behaviour in terms of the relative amounts of weakly absorbing material and black carbon in a particle we show a sharp transition in mixing occurs. We show that the majority of black carbon particles from traffic-dominated sources can be treated as externally mixed and show no absorption enhancement, whereas models assuming internal mixing tend to give the best estimate of the absorption enhancement of thickly coated black carbon particles from biofuel or biomass burning. This approach reconciles the differences in absorption enhancement previously observed and offers a systematic way of treating the differences in behaviour observed.

Emotion recognition impairment in traumatic brain injury compared with schizophrenia spectrum: similar deficits with different origins.

PubMed

Mancuso, Mauro; Magnani, Nadia; Cantagallo, Anna; Rossi, Giulia; Capitani, Donatella; Galletti, Vania; Cardamone, Giuseppe; Robertson, Ian Hamilton

2015-02-01

The aim of our study was to identify the common and separate mechanisms that might underpin emotion recognition impairment in patients with traumatic brain injury (TBI) and schizophrenia (Sz) compared with healthy controls (HCs). We recruited 21 Sz outpatients, 24 severe TBI outpatients, and 38 HCs, and we used eye-tracking to compare facial emotion processing performance. Both Sz and TBI patients were significantly poorer at recognizing facial emotions compared with HC. Sz patients showed a different way of exploring the Pictures of Facial Affects stimuli and were significantly worse in recognition of neutral expressions. Selective or sustained attention deficits in TBI may reduce efficient emotion recognition, whereas in Sz, there is a more strategic deficit underlying the observed problem. There would seem to be scope for adjustment of effective rehabilitative training focused on emotion recognition.

Spectrum Project

NASA Image and Video Library

2017-10-16

Dr. Scott Shipley of Ascentech Enterprises makes an adjustment to the Spectrum unit. He is the project engineer for the effort working under the Engineering Services Contract at NASA's Kennedy Space Center. The device is being built for use aboard the International Space Station and is designed to expose different organisms to different color of fluorescent light while a camera records what's happening with time-laps imagery. Results from the Spectrum project will shed light on which living things are best suited for long-duration flights into deep space.

Expanding the clinical spectrum of COL1A1 mutations in different forms of glaucoma.

PubMed

Mauri, Lucia; Uebe, Steffen; Sticht, Heinrich; Vossmerbaeumer, Urs; Weisschuh, Nicole; Manfredini, Emanuela; Maselli, Edoardo; Patrosso, Mariacristina; Weinreb, Robert N; Penco, Silvana; Reis, André; Pasutto, Francesca

2016-08-02

associated with different ocular abnormalities, although recognition of the common pathology for both features is seldom being recognized. Our results expand the role of COL1A1 mutations in different forms of early-onset glaucoma with and without signs of OI. Thus, we suggest including COL1A1 mutation screening in the genetic work-up of glaucoma cases and detailed ophthalmic examinations with fundus analysis in patients with OI.

Attention selectively modulates cortical entrainment in different regions of the speech spectrum

PubMed Central

Baltzell, Lucas S.; Horton, Cort; Shen, Yi; Richards, Virginia M.; D'Zmura, Michael; Srinivasan, Ramesh

2016-01-01

Recent studies have uncovered a neural response that appears to track the envelope of speech, and have shown that this tracking process is mediated by attention. It has been argued that this tracking reflects a process of phase-locking to the fluctuations of stimulus energy, ensuring that this energy arrives during periods of high neuronal excitability. Because all acoustic stimuli are decomposed into spectral channels at the cochlea, and this spectral decomposition is maintained along the ascending auditory pathway and into auditory cortex, we hypothesized that the overall stimulus envelope is not as relevant to cortical processing as the individual frequency channels; attention may be mediating envelope tracking differentially across these spectral channels. To test this we reanalyzed data reported by Horton et al. (2013), where high-density EEG was recorded while adults attended to one of two competing naturalistic speech streams. In order to simulate cochlear filtering, the stimuli were passed through a gammatone filterbank, and temporal envelopes were extracted at each filter output. Following Horton et al. (2013), the attended and unattended envelopes were cross-correlated with the EEG, and local maxima were extracted at three different latency ranges corresponding to distinct peaks in the cross-correlation function (N1, P2, and N2). We found that the ratio between the attended and unattended cross-correlation functions varied across frequency channels in the N1 latency range, consistent with the hypothesis that attention differentially modulates envelope-tracking activity across spectral channels. PMID:27195825

Differences in fecal microbial metabolites and microbiota of children with autism spectrum disorders

DOE PAGES

Kang, Dae-Wook; Ilhan, Zehra Esra; Isern, Nancy G.; ...

2017-12-22

Evidence supporting that gut problems are linked to ASD symptoms has been accumulating both in humans and animal models of ASD. Gut microbes and their metabolites may be linked not only to GI problems but also to ASD behavior symptoms. Despite this high interest, most previous studies have looked mainly at microbial structure, and studies on fecal metabolites are rare in the context of ASD. Thus, we aimed to detect fecal metabolites that may be present at significantly different concentrations between 21 children with ASD and 23 neurotypical children and to investigate its possible link to human gut microbiome. Usingmore » 1H-NMR spectroscopy and 16S rRNA gene amplicon sequencing, we examined metabolite profiles and microbial compositions in fecal samples, respectively. Of the 59 metabolites detected, isopropanol concentrations were significantly higher in feces of children with ASD after multiple testing corrections. We also observed similar trends of fecal metabolites to previous studies; children with ASD have higher fecal p-cresol and possibly lower GABA concentrations. In addition, Fisher Discriminant Analysis (FDA) with leave-out-validation suggested that a group of metabolites-caprate, nicotinate, glutamine, thymine, and aspartate-may potentially function as a modest biomarker to separate ASD participants from the neurotypical group (78% sensitivity and 81% specificity). Consistent with our previous Arizona cohort study, we also confirmed lower gut microbial diversity and reduced relative abundances of phylotypes most closely related to Prevotella copri in children with ASD. After multiple testing corrections, we also learned that relative abundances of Feacalibacterium prausnitzii and Haemophilus parainfluenzae were lower in feces of children with ASD. In conclusion, despite a relatively short list of fecal metabolites, the data in this study support that children with ASD have altered metabolite profiles in feces when compared with neurotypical children

Differences in fecal microbial metabolites and microbiota of children with autism spectrum disorders

SciTech Connect

Kang, Dae-Wook; Ilhan, Zehra Esra; Isern, Nancy G.

Evidence supporting that gut problems are linked to ASD symptoms has been accumulating both in humans and animal models of ASD. Gut microbes and their metabolites may be linked not only to GI problems but also to ASD behavior symptoms. Despite this high interest, most previous studies have looked mainly at microbial structure, and studies on fecal metabolites are rare in the context of ASD. Thus, we aimed to detect fecal metabolites that may be present at significantly different concentrations between 21 children with ASD and 23 neurotypical children and to investigate its possible link to human gut microbiome. Usingmore » NMR spectroscopy and 16S rRNA gene amplicon sequencing, we examined metabolite profiles and microbial compositions in fecal samples, respectively. Of the 59 metabolites detected, isopropanol concentrations were significantly higher in feces of children with ASD after multiple testing corrections. We also observed similar trends of fecal metabolites to previous studies; children with ASD have higher fecal p-cresol and possibly lower GABA concentrations. In addition, Fisher Discriminant Analysis (FDA) with leave-out-validation suggested that a group of metabolites- caprate, nicotinate, glutamine, thymine, and aspartate- may potentially function as a biomarker to separate ASD participants from the neurotypical group (78% sensitivity and 81% specificity). Consistent with our previous Arizona cohort study, we also confirmed lower gut microbial diversity and reduced relative abundances of Prevotella copri in children with ASD. After multiple testing corrections, we also learned that relative abundances of Feacalibacterium prausnitzii and Haemophilus parainfluenzae were lower in feces of children with ASD. Despite a relatively short list of fecal metabolites, the data in this study support that children with ASD have altered metabolite profiles in feces when compared with neurotypical children and warrant further investigation of metabolites in larger

Differences in fecal microbial metabolites and microbiota of children with autism spectrum disorders

SciTech Connect

Kang, Dae-Wook; Ilhan, Zehra Esra; Isern, Nancy G.

Evidence supporting that gut problems are linked to ASD symptoms has been accumulating both in humans and animal models of ASD. Gut microbes and their metabolites may be linked not only to GI problems but also to ASD behavior symptoms. Despite this high interest, most previous studies have looked mainly at microbial structure, and studies on fecal metabolites are rare in the context of ASD. Thus, we aimed to detect fecal metabolites that may be present at significantly different concentrations between 21 children with ASD and 23 neurotypical children and to investigate its possible link to human gut microbiome. Usingmore » 1H-NMR spectroscopy and 16S rRNA gene amplicon sequencing, we examined metabolite profiles and microbial compositions in fecal samples, respectively. Of the 59 metabolites detected, isopropanol concentrations were significantly higher in feces of children with ASD after multiple testing corrections. We also observed similar trends of fecal metabolites to previous studies; children with ASD have higher fecal p-cresol and possibly lower GABA concentrations. In addition, Fisher Discriminant Analysis (FDA) with leave-out-validation suggested that a group of metabolites-caprate, nicotinate, glutamine, thymine, and aspartate-may potentially function as a modest biomarker to separate ASD participants from the neurotypical group (78% sensitivity and 81% specificity). Consistent with our previous Arizona cohort study, we also confirmed lower gut microbial diversity and reduced relative abundances of phylotypes most closely related to Prevotella copri in children with ASD. After multiple testing corrections, we also learned that relative abundances of Feacalibacterium prausnitzii and Haemophilus parainfluenzae were lower in feces of children with ASD. In conclusion, despite a relatively short list of fecal metabolites, the data in this study support that children with ASD have altered metabolite profiles in feces when compared with neurotypical children

The wide spectrum high biocidal potency of Bioxy formulation when dissolved in water at different concentrations

PubMed Central

Dagher, Fadi

2017-01-01

Traditional surface disinfectants that have long been applied in medicine, animal husbandry, manufacturing and institutions are inconvenient at best and dangerous at worst. Moreover, some of these substances have adverse environmental impacts: for example, quaternary ammonium compounds (“quats”) are reproductive toxicants in both fish and mammals. Halogens are corrosive both to metals and living tissues, are highly reactive, can be readily neutralized by metals, and react with organic matter to form toxic, persistent by-products such as dioxins and furans. Aldehydes may be carcinogenic to both human and animals upon repeated exposures, are corrosive, cross-link living tissues and many synthetic materials, and may lose efficacy when pathogens enzymatically adapt to them. Alcohols are flammable and volatile and can be enzymatically degraded by certain bacterial pathogens. Quats are highly irritating to mucous membranes and over time can induce pathogen resistance, especially if they are not alternated with functionally different disinfectants. In contrast, peracetic acid (PAA), a potent oxidizer, liberates hydrogen peroxide (itself a disinfectant), biodegrades to carbon dioxide, water and oxygen, and is at least as efficacious as contact biocides e.g., halogens and aldehydes. Nevertheless, the standard form of liquid PAA is highly corrosive, is neutralized by metals and organic matter, gives off noxious odours and must be stored in vented containers. For the reasons stated above, Bioxy formulations were developed, a series of powder forms of PAA, which are odourless, stable in storage and safe to transport and handle. They generate up to 10% PAA in situ when dissolved in water. A 0.2% aqueous solution of Bioxy (equivalent to 200 ppm PAA) effected a 6.76 log reduction in Methicillin-resistant Staphylococcus aureus (MRSA) within 2 minutes after application. A 5% aqueous solution of Bioxy achieved a 3.93 log reduction in the bovine tuberculosis bacillus

The wide spectrum high biocidal potency of Bioxy formulation when dissolved in water at different concentrations.

PubMed

Dagher, Dori; Ungar, Ken; Robison, Richard; Dagher, Fadi

2017-01-01

Traditional surface disinfectants that have long been applied in medicine, animal husbandry, manufacturing and institutions are inconvenient at best and dangerous at worst. Moreover, some of these substances have adverse environmental impacts: for example, quaternary ammonium compounds ("quats") are reproductive toxicants in both fish and mammals. Halogens are corrosive both to metals and living tissues, are highly reactive, can be readily neutralized by metals, and react with organic matter to form toxic, persistent by-products such as dioxins and furans. Aldehydes may be carcinogenic to both human and animals upon repeated exposures, are corrosive, cross-link living tissues and many synthetic materials, and may lose efficacy when pathogens enzymatically adapt to them. Alcohols are flammable and volatile and can be enzymatically degraded by certain bacterial pathogens. Quats are highly irritating to mucous membranes and over time can induce pathogen resistance, especially if they are not alternated with functionally different disinfectants. In contrast, peracetic acid (PAA), a potent oxidizer, liberates hydrogen peroxide (itself a disinfectant), biodegrades to carbon dioxide, water and oxygen, and is at least as efficacious as contact biocides e.g., halogens and aldehydes. Nevertheless, the standard form of liquid PAA is highly corrosive, is neutralized by metals and organic matter, gives off noxious odours and must be stored in vented containers. For the reasons stated above, Bioxy formulations were developed, a series of powder forms of PAA, which are odourless, stable in storage and safe to transport and handle. They generate up to 10% PAA in situ when dissolved in water. A 0.2% aqueous solution of Bioxy (equivalent to 200 ppm PAA) effected a 6.76 log reduction in Methicillin-resistant Staphylococcus aureus (MRSA) within 2 minutes after application. A 5% aqueous solution of Bioxy achieved a 3.93 log reduction in the bovine tuberculosis bacillus Mycobacterium

Determination of water pH using absorption-based optical sensors: evaluation of different calculation methods

NASA Astrophysics Data System (ADS)

Wang, Hongliang; Liu, Baohua; Ding, Zhongjun; Wang, Xiangxin

2017-02-01

Absorption-based optical sensors have been developed for the determination of water pH. In this paper, based on the preparation of a transparent sol-gel thin film with a phenol red (PR) indicator, several calculation methods, including simple linear regression analysis, quadratic regression analysis and dual-wavelength absorbance ratio analysis, were used to calculate water pH. Results of MSSRR show that dual-wavelength absorbance ratio analysis can improve the calculation accuracy of water pH in long-term measurement.

High resolution absorption spectrum of CO2between 1750 and 2000 Å. 2. Rotational analysis of two parallel-type bands assigned to the lowest electronic transition 13B2←

NASA Astrophysics Data System (ADS)

Cossart-Magos, Claudina; Launay, Françoise; Parkin, James E.

The absorption spectrum of CO2 gas between 175 and 200 nm was photographed at high resolution some years ago. This very weak spectral region proved to be extremely rich in bands showing rotational fine structure. In Part 1 [C. Cossart-Magos, F. Launay, J. E. Parkin, Mol. Phys., 75, 835 (1992), nine perpendicular-type bands were assigned to the lowest singlet-singlet transition, 11A2 ← ν'3 (b2) vibration. Here, the parallel-type bands observed at 185.7 and 175.6 nm are assigned to the lowest triplet-singlet transition, 13B2 ← TMPH0629math005 ν'2 (a1) vibration. The assignment and the rotational and spin constant values obtained are discussed in relation to previous experimental data and ab initio calculation results on the lowest excited states of CO2. The actual role of the 13B2 state in CO2 photodissociation, O(3P)+CO(X1Σ+) recombination, and O(1D) emission quenching by CO(X) molecules is reviewed.

The art of camouflage: Gender differences in the social behaviors of girls and boys with autism spectrum disorder.

PubMed

Dean, Michelle; Harwood, Robin; Kasari, Connie

2017-08-01

This study examined the extent to which gender-related social behaviors help girls with autism spectrum disorder to seemingly mask their symptoms. Using concurrent mixed methods, we examined the social behaviors of 96 elementary school children during recess (autism spectrum disorder = 24 girls and 24 boys, typically developing = 24 girls and 24 boys). Children with autism spectrum disorder had average intelligence (IQ ⩾ 70), a confirmed diagnosis, and were educated in the general education classroom. Typically developing children were matched by sex, age, and city of residence to children with autism spectrum disorder. The results indicate that the female social landscape supports the camouflage hypothesis; girls with autism spectrum disorder used compensatory behaviors, such as staying in close proximately to peers and weaving in and out of activities, which appeared to mask their social challenges. Comparatively, the male landscape made it easier to detect the social challenges of boys with autism spectrum disorder. Typically developing boys tended to play organized games; boys with autism spectrum disorder tended to play alone. The results highlight a male bias in our perception of autism spectrum disorder. If practitioners look for social isolation on the playground when identifying children with social challenges, then our findings suggest that girls with autism spectrum disorder will continue to be left unidentified.

Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders.

PubMed

Masuya, Yasuhiro; Okamoto, Yuko; Inohara, Keisuke; Matsumura, Yukiko; Fujioka, Toru; Wada, Yuji; Kosaka, Hirotaka

2015-01-01

The prevalence of autism spectrum disorders (ASDs) is higher in men than in women. The extreme male brain theory proposes that excessive prenatal testosterone activity could be a risk factor for ASDs. However, it is unclear whether prenatal sex hormone activity is a risk factor for women. The ratio of the length of the second to fourth digits (2D:4D) is considered to be a biomarker of the prenatal ratio of testosterone to estrogen. Therefore, this study compared the 2D:4D ratios of women with and without ASDs to determine if prenatal sex hormone activity could be a risk factor for ASDs in women. The study included 35 Japanese men with ASDs, 17 Japanese women with ASDs, 59 typically developed (TD) Japanese men, and 57 TD Japanese women. We measured digit lengths and compared the 2D:4D ratios among the four groups. We also examined the relationship between the 2D:4D ratio and the autism-spectrum quotient score of each group. In our cohort, men with ASDs tended to have lower right-hand 2D:4D ratios relative to TD men. In contrast, the right 2D:4D ratios in women with ASDs were higher compared to those of TD women. No significant correlations were found between the 2D:4D ratios and the autism-spectrum quotient scores in any group. The higher right 2D:4D ratios in women could not be explained by age or full-scale intelligent quotients. This group difference was not found for the left 2D:4D or right-left 2D:4D ratios. We found a reverse direction of abnormality in the right 2D:4D ratio for men and women with ASDs. It has been posited that high prenatal testosterone levels lead to a lower 2D:4D ratio. However, a recent animal study showed that testosterone injection to dam leads to a higher right 2D:4D ratio especially for female offspring, which might be mediated by abnormal adipose accumulation in the fingertip. Therefore, the present findings suggest that high prenatal testosterone could be a risk factor both for Japanese men and women with ASDs, elucidating one

Selective optical contacting for solar spectrum management

NASA Astrophysics Data System (ADS)

Yang, Jianfeng; Chen, Weijian; Wang, Bo; Zhang, Zhilong; Huang, Shujuan; Shrestha, Santosh; Wen, Xiaoming; Patterson, Robert; Conibeer, Gavin

2017-02-01

Solar spectrum management using up/down conversion is an important method to improve the photovoltaic energy conversion efficiency. It asks for a monochromatic luminescence absorption at the band edge of the photovoltaic device to reduce both the sub-band-gap and over-band-gap energy losses. Here, we demonstrate an energy selective optical contacting concept to improve the luminescence transfer efficiency for spectrum management. By increasing both the luminescence emission and re-absorption ability through photonic resonance, an efficient photon transfer channel could be established between the luminescence emitter and the photovoltaic component in a near-field region. This concept is not only able to compensate the insufficient band edge absorption ability of the photovoltaic device, but also to break the far-field limitation of luminescence radiation. The energy selection on the optical spectrum naturally imposed by the mode resonance is also helpful to improve the monochromaticity of the luminescence yield. In this paper, a photonic crystal cavity is used to realize the optical contacting concept between a thin silicon film and spectrum converter. The optical power and photon flux transferred between different components are calculated analytically using the electromagnetic Green's function. The corresponding radiative dipole moment is estimated by the fluctuation-dissipation theorem. The example shows an over 80 times enhancement in the luminescence absorbance by the silicon layer, illustrating the great potential of this concept to be applied on nano-structured photovoltaic devices.

[UV-Vis spectrum characteristics of phycocyanin in water from Taihu lake].

PubMed

Zhang, Jing; Wei, Yu-Chun; Wang, Guo-Xiang; Cheng, Chun-Mei; Xia, Xiao-Rui

2014-05-01

The present paper analyzed the UV-Vis spectrum characteristics of phycocyanin extracted from 75 water samples around Meiliang Bay of Taihu Lake, China in spring, summer and autumn, 2011, taking standard sample of phycocyanin, Micro-cystic aeruginosa and Anabaena cultured indoor as the reference, and discussed the difference and relation of spectrum among water samples, standard sample and single algae samples. According to the number of absorption peak in the wavelength range from 500 to 700 nm, phycocyanin spectrum of water sampling in Taihu Lake can be divided into three patterns: no peak, single peak and two peaks. In the first pattern, the absorbance changed smoothly and no absorption peak was observed around 620 nm. Depending on the absorption difference in the wavelength range from 300 to 450 nm, this pattern can be divided into type I and type II. Type I only had a absorption peak near 260 nm, with the similar spectrum of chromophoric dissolved organic matter (CDOM) in the wavelength range from 250 to 800 nm. Type II had absorption peak respectively near 260 and 330 nm. In single peak pattern and two peaks pattern, significant absorption peak of phycocyanin appeared around 620 nm. Compared to the other patterns, single peak pattern was more similar to that of standard sample and single algae samples, but different in their maximum absorption peaks position and relative absorption intensity in the wavelength range of 250 approximately 300, 300 approximately 450 and 500 approximately 700 nm, because of different algae species and purity after extraction. In the two peaks pattern, another absorption peak appeared at 670nm, with the absorption shoulder from 350 to 450 nm, and shared the absorption characteristics of phycocyanin and chlorophyll complex protein. The research can provide a basic support for the phycocyanin quantitation and blooms monitoring in Taihu Lake.

Effects of different soil remediation methods on inhibition of lead absorption and growth and quality of Dianthus superbus L.

PubMed

Yang, Xiaoyu; Ma, Siyue; Li, Jianheng

2017-12-01

Heavy metal pollution in soil poses a serious threat to the growth of plants used in traditional Chinese medicine. Therefore, a pot experiment was conducted to study the effects of various soil remediation methods on the performance of Herba Dianthi (Dianthus superbus L.) grown on Pb-contaminated soil. The results show that inoculation of Herba Dianthi with arbuscular mycorrhizal fungi (AMF) led to a significant reduction in Pb uptake (P< 0.05), and increased root development and root-to-shoot ratio compared to untreated control plants, along with the highest content of active components. When planting with Trifolium repens, the reduction effect of Pb absorption was insignificant. Herba Dianthi showed improved growth and active ingredients, and the lowest Pb content, with AMF inoculation. The addition of EDTA decreased the growth of Herba Dianthi, but promoted the absorption of Pb. The inhibition of tumor cells was highest in E2. In conclusion, inoculation with AMF can ensure that plant lead content meets testing standards, helping to improve the quality of medicinal herbs.

Probing the global potential energy minimum of (CH2O)2: THz absorption spectrum of (CH2O)2 in solid neon and para-hydrogen

NASA Astrophysics Data System (ADS)

Andersen, J.; Voute, A.; Mihrin, D.; Heimdal, J.; Berg, R. W.; Torsson, M.; Wugt Larsen, R.

2017-06-01

The true global potential energy minimum configuration of the formaldehyde dimer (CH2O)2, including the presence of a single or a double weak intermolecular CH⋯O hydrogen bond motif, has been a long-standing subject among both experimentalists and theoreticians as two different energy minima conformations of Cs and C2h symmetry have almost identical energies. The present work demonstrates how the class of large-amplitude hydrogen bond vibrational motion probed in the THz region provides excellent direct spectroscopic observables for these weak intermolecular CH⋯O hydrogen bond motifs. The combination of concentration dependency measurements, observed isotopic spectral shifts associated with H/D substitutions and dedicated annealing procedures, enables the unambiguous assignment of three large-amplitude infrared active hydrogen bond vibrational modes for the non-planar Cs configuration of (CH2O)2 embedded in cryogenic neon and enriched para-hydrogen matrices. A (semi)-empirical value for the change of vibrational zero-point energy of 5.5 ± 0.3 kJ mol-1 is proposed for the dimerization process. These THz spectroscopic observations are complemented by CCSD(T)-F12/aug-cc-pV5Z (electronic energies) and MP2/aug-cc-pVQZ (force fields) electronic structure calculations yielding a (semi)-empirical value of 13.7 ± 0.3 kJ mol-1 for the dissociation energy D0 of this global potential energy minimum.

Probing the global potential energy minimum of (CH2O)2: THz absorption spectrum of (CH2O)2 in solid neon and para-hydrogen.

PubMed

Andersen, J; Voute, A; Mihrin, D; Heimdal, J; Berg, R W; Torsson, M; Wugt Larsen, R

2017-06-28

The true global potential energy minimum configuration of the formaldehyde dimer (CH 2 O) 2 , including the presence of a single or a double weak intermolecular CH⋯O hydrogen bond motif, has been a long-standing subject among both experimentalists and theoreticians as two different energy minima conformations of C s and C 2h symmetry have almost identical energies. The present work demonstrates how the class of large-amplitude hydrogen bond vibrational motion probed in the THz region provides excellent direct spectroscopic observables for these weak intermolecular CH⋯O hydrogen bond motifs. The combination of concentration dependency measurements, observed isotopic spectral shifts associated with H/D substitutions and dedicated annealing procedures, enables the unambiguous assignment of three large-amplitude infrared active hydrogen bond vibrational modes for the non-planar C s configuration of (CH 2 O) 2 embedded in cryogenic neon and enriched para-hydrogen matrices. A (semi)-empirical value for the change of vibrational zero-point energy of 5.5 ± 0.3 kJ mol -1 is proposed for the dimerization process. These THz spectroscopic observations are complemented by CCSD(T)-F12/aug-cc-pV5Z (electronic energies) and MP2/aug-cc-pVQZ (force fields) electronic structure calculations yielding a (semi)-empirical value of 13.7 ± 0.3 kJ mol -1 for the dissociation energy D 0 of this global potential energy minimum.

Dissociation in patients with schizophrenia spectrum disorders: What is the role of different types of childhood adversity?

PubMed

Schroeder, Katrin; Langeland, Willemien; Fisher, Helen L; Huber, Christian G; Schäfer, Ingo

2016-07-01

Our study aimed to explore the effects of different types of adverse childhood experiences (e.g. domestic violence, early loss, parental dysfunction, sexual and physical abuse) as well as experiences of sexual and physical abuse in adulthood on dissociative symptoms in adult patients with schizophrenia-spectrum disorders. 145 patients were examined for psychotic symptoms with the Positive and Negative Syndrome Scale (PANSS), for dissociative symptoms with the German version of the Dissociative Experiences Scale (DES) and for adverse experiences in childhood and adulthood with the Structured Trauma Interview (STI). Childhood physical abuse was reported by 32%, childhood sexual abuse by 17% of the patients. Other forms of childhood adversity were also quite common; 18% had witnessed domestic violence, 26% reported early loss, and nearly half of patients reported at least one condition potentially related to parental dysfunction. The DES total score was significantly associated with childhood sexual abuse, witnessing of domestic violence and paternal dysfunction, as well as with physical violence in adulthood. In the final regression model, reports of paternal dysfunction and sexual abuse in childhood were independently associated with adult dissociation. Variance in dissociative symptoms was mainly explained by paternal dysfunction (18%). Substantial rates of childhood adversity were found and specific associations were evident with adult dissociation amongst psychosis patients who reported sexual abuse or paternal dysfunction in childhood. Therefore, it is important that patients with schizophrenia-spectrum disorders are routinely asked about a broad range of possible adverse childhood experiences in order to provide appropriate interventions. Copyright © 2016 Elsevier Inc. All rights reserved.

Sex-related differences in auditory processing in adolescents with fetal alcohol spectrum disorder: A magnetoencephalographic study.

PubMed

Tesche, Claudia D; Kodituwakku, Piyadasa W; Garcia, Christopher M; Houck, Jon M

2015-01-01

Children exposed to substantial amounts of alcohol in utero display a broad range of morphological and behavioral outcomes, which are collectively referred to as fetal alcohol spectrum disorders (FASDs). Common to all children on the spectrum are cognitive and behavioral problems that reflect central nervous system dysfunction. Little is known, however, about the potential effects of variables such as sex on alcohol-induced brain damage. The goal of the current research was to utilize magnetoencephalography (MEG) to examine the effect of sex on brain dynamics in adolescents and young adults with FASD during the performance of an auditory oddball task. The stimuli were short trains of 1 kHz "standard" tone bursts (80%) randomly interleaved with 1.5 kHz "target" tone bursts (10%) and "novel" digital sounds (10%). Participants made motor responses to the target tones. Results are reported for 44 individuals (18 males and 26 females) ages 12 through 22 years. Nine males and 13 females had a diagnosis of FASD and the remainder were typically-developing age- and sex-matched controls. The main finding was widespread sex-specific differential activation of the frontal, medial and temporal cortex in adolescents with FASD compared to typically developing controls. Significant differences in evoked-response and time-frequency measures of brain dynamics were observed for all stimulus types in the auditory cortex, inferior frontal sulcus and hippocampus. These results underscore the importance of considering the influence of sex when analyzing neurophysiological data in children with FASD.

[A study of complexity and power spectrum of cortical EEG and hippocampal potential in rats under different behavioral states].

PubMed

Feng, Zhou-yan; Zheng, Xiao-xiang

2002-08-01

Objective. To study the complexity and the power spectrum of cortical EEG and hippocampal potential in rats under waking and sleep states. Method. Cortical EEG and hippocampal potential were collected by implanted electrodes in freely moving rats. Algorithmic complexity (Kc), approximate entropy (ApEn), power spectral density (PSD) and gravity frequency of PSD of the potential waves were calculated. Result. The complexity of hippocampal potential was higher than that of cortical EEG under every state. The complexity of cortical EEG was lowest under the state of non rapid eye movement (NREM) sleep. The complexity of hippocampal potential was highest under waking state. The total power of both potentials in 0.5- 30 Hz frequency band showed their highest values under NREM state. Conclusion. The values of Kc and ApEn are closely related to the distributions of PSD. When there are evident peaks in PSD, the complexities of signals will decrease. The complexities may be used to distinguish the difference between cortical EEG and hippocampal potential, or large differences between the same kind of potentials under different behavioral states.

The Art of Camouflage: Gender Differences in the Social Behaviors of Girls and Boys with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Dean, Michelle; Harwood, Robin; Kasari, Connie

2017-01-01

This study examined the extent to which gender-related social behaviors help girls with autism spectrum disorder to seemingly mask their symptoms. Using concurrent mixed methods, we examined the social behaviors of 96 elementary school children during recess (autism spectrum disorder = 24 girls and 24 boys, typically developing = 24 girls and 24…

Tropical dry forest trees and lianas differ in leaf economic spectrum traits but have overlapping water-use strategies.

PubMed

Werden, Leland K; Waring, Bonnie G; Smith-Martin, Christina M; Powers, Jennifer S

2018-04-01

Tree species in tropical dry forests employ a wide range of strategies to cope with seasonal drought, including regulation of hydraulic function. However, it is uncertain if co-occurring lianas also possess a diversity of strategies. For a taxonomically diverse group of 14 tree and 7 liana species, we measured morphological and hydraulic functional traits during an unusual drought and under non-drought conditions to determine (i) if trees have different water-use strategies than lianas and (ii) if relationships among these traits can be used to better understand how tree and liana species regulate diurnal leaf water potential (Ψdiurnal). In this Costa Rican tropical dry forest, lianas and trees had overlapping water-use strategies, but differed in many leaf economic spectrum traits. Specifically, we found that both lianas and trees employed a diversity of Ψdiurnal regulation strategies, which did not differ statistically. However, lianas and trees did significantly differ in terms of certain traits including leaf area, specific leaf area, petiole length, wood vessel diameter and xylem vessel density. All liana and tree species we measured fell along a continuum of isohydric (partial) to anisohydric (strict or extreme) Ψdiurnal regulation strategies, and leaf area, petiole length, stomatal conductance and wood vessel diameter correlated with these strategies. These findings contribute to a trait-based understanding of how plants regulate Ψdiurnal under both drought stress and sufficient water availability, and underscore that lianas and trees employ a similarly wide range of Ψdiurnal regulation strategies, despite having vastly different growth forms.

Differences in the intramolecular structure of structured oils do not affect pancreatic lipase activity in vitro or the absorption by rats of (n-3) fatty acids.

PubMed

Porsgaard, Trine; Xu, Xuebing; Göttsche, Jesper; Mu, Huiling

2005-07-01

The fatty acid composition and intramolecular structure of dietary triacylglycerols (TAGs) influence their absorption. We compared the in vitro pancreatic lipase activity and the lymphatic transport in rats of fish oil and 2 enzymatically interesterified oils containing 10:0 and (n-3) PUFAs of marine origin to investigate whether the positional distribution of fatty acids influenced the overall bioavailability of (n-3) PUFAs in the body. The structured oils had the (n-3) PUFA either mainly at the sn-1,3 position (LML, M = medium-chain fatty acid, L = long-chain fatty acid) or mainly at the sn-2 position (MLM). Oils were administered to lymph-cannulated rats and lymph was collected for 24 h. The fatty acid composition as well as the lipid class distribution of lymph samples was determined. In vitro pancreatic lipase activity was greater when fish oil was the substrate than when the structured oils were the substrates (P < 0.001 at 40 min). This was consistent with a greater 8-h recovery of total fatty acids from fish oil compared with the 2 structured oils (P < 0.05). The absorption profiles of MLM and LML in rats and their in vitro rates of lipase activity did not differ. This indicates that the absorption rate is highly influenced by the lipase activity, which in turn is affected by the fatty acid composition and intramolecular structure. The lipid class distribution in lymph collected from the 3 groups of rats did not differ. In conclusion, the intramolecular structure did not affect the overall absorption of (n-3) PUFAs.

The connectomes of males and females with autism spectrum disorder have significantly different white matter connectivity densities

PubMed Central

Irimia, Andrei; Torgerson, Carinna M.; Jacokes, Zachary J.; Van Horn, John D.

2017-01-01

Autism spectrum disorder (ASD) encompasses a set of neurodevelopmental conditions whose striking sex-related disparity (with an estimated male-to-female ratio of 4:1) remains unknown. Here we use magnetic resonance imaging (MRI) and diffusion weighted imaging (DWI) to identify the brain structure correlates of the sex-by-ASD diagnosis interaction in a carefully selected cohort of 110 ASD patients (55 females) and 83 typically-developing (TD) subjects (40 females). The interaction was found to be predicated primarily upon white matter connectivity density innervating, bilaterally, the lateral aspect of the temporal lobe, the temporo-parieto-occipital junction and the medial parietal lobe. By contrast, regional gray matter (GM) thickness and volume are not found to modulate this interaction significantly. When interpreted in the context of previous studies, our findings add considerable weight to three long-standing hypotheses according to which the sex disparity of ASD incidence is (A) due to WM connectivity rather than to GM differences, (B) modulated to a large extent by temporoparietal connectivity, and (C) accompanied by brain function differences driven by these effects. Our results contribute substantially to the task of unraveling the biological mechanisms giving rise to the sex disparity in ASD incidence, whose clinical implications are significant. PMID:28397802

Direct medical costs and source of cost differences across the spectrum of cognitive decline: A population-based study

PubMed Central

Leibson, Cynthia L.; Long, Kirsten Hall; Ransom, Jeanine E.; Roberts, Rosebud O.; Hass, Steven L.; Duhig, Amy M.; Smith, Carin Y.; Emerson, Jane A.; Pankratz, V. Shane; Petersen, Ronald C.

2015-01-01

BACKGROUND Objective cost estimates and source of cost differences are needed across the spectrum of cognition, including cognitively normal (CN), mild-cognitive-impairment (MCI), newly-discovered dementia, and prevalent dementia. METHODS Subjects were a subset of the Mayo Clinic Study of Aging stratified-random sampling of Olmsted County, MN, residents aged 70-89 years. A neurologist reviewed provider-linked medical records to identify prevalent-dementia (review date=index). Remaining subjects were invited to participate in prospective clinical/neuropsychological assessments; participants were categorized as CN, MCI, or newly-discovered-dementia (assessment date=index). Costs for medical services/procedures 1-year pre-index (excluding indirect and long-term care costs) were estimated using line-item provider-linked administrative data. We estimated contributions of care-delivery site and comorbid conditions (including and excluding neuropsychiatric diagnoses) to between-category cost differences. RESULTS Annual mean medical costs for CN, MCI, newly-discovered-dementia, and prevalent-dementia were $6,042, $6,784, $9,431, $11,678 respectively. Hospital inpatient costs contributed 70% of total costs for prevalent dementia and accounted for differences between CN and both prevalent and newly-discovered dementia. Ambulatory costs accounted for differences between CN and MCI. Age-, sex-, education-adjusted differences reached significance for CN versus newly-discovered and prevalent-dementia and for MCI versus prevalent-dementia. After considering all comorbid diagnoses, between-category differences were reduced (e.g., prevalent-dementia minus MCI (from $4,842 to $3,575); newly-discovered-dementia minus CN (from $3,578 to$711). Following exclusion of neuropsychiatric diagnoses from comorbidity adjustment, between-category differences tended to revert to greater differences. CONCLUSIONS Cost estimates did not differ significantly between CN and MCI. Substantial

Quantification of absorption, retention and elimination of two different oral doses of vitamin A in Zambian boys using accelerator mass spectrometry

SciTech Connect

Aklamati, E K; Mulenga, M; Dueker, S R

A recent survey indicated that high-dose vitamin A supplements (HD-VAS) had no apparent effect on vitamin A (VA) status of Zambian children <5 y of age. To explore possible reasons for the lack of response to HD-VAS among Zambian children, we quantified the absorption, retention, and urinary elimination of either a single HDVAS (60 mg) or a smaller dose of stable isotope (SI)-labeled VA (5 mg), which was used to estimate VA pool size, in 3-4 y old Zambian boys (n = 4 for each VA dose). A 25 nCi tracer dose of [{sup 14}C{sub 2}]-labeled VA was co-administered withmore » the HD-VAS or SI-labeled VA, and 24-hr stool and urine samples were collected for 3 and 7 consecutive days, respectively, and 24-hr urine samples at 4 later time points. Accelerator Mass Spectrometry (AMS) was used to measure the cumulative excretion of {sup 14}C in stool and urine 3d after dosing to estimate, respectively, absorption and retention of the VAS and SI-labeled VA. The urinary elimination rate (UER) was estimated by plotting {sup 14}C in urine vs. time, and fitting an exponential equation to the data. Estimates of mean absorption, retention and the UER were 83.8 {+-} 7.1%, 76.3 {+-} 6.7%, and 1.9 {+-} 0.6%/d, respectively, for the HD-VAS and 76.5 {+-} 9.5%, 71.1 {+-} 9.4%, and 1.8 {+-} 1.2%/d, respectively for the smaller dose of SI-labeled VA. Estimates of absorption, retention and the UER did not differ by size of the VA dose administered (P=0.26, 0.40, 0.88, respectively). Estimated absorption and retention were negatively associated with reported fever (P=0.011) and malaria (P =0.010). HD-VAS and SI-labeled VA were adequately absorbed, retained and utilized in apparently healthy Zambian preschool-age boys, although absorption and retention may be affected by recent infections.« less

OPTICAL ABSORPTION SPECTRUM OF ANTIFERROMAGNETIC MNF2.

DTIC Science & Technology

separated in energy and easily identifiable, (3) has a very simple ground state, and (4) has a well studied magnon structure, an investigation was...undertaken of the excited states in the hope of observing other magnetic dipole transitions and their accompanying magnon sidebands. This study was...similarities between the magnon sidebands in several excited states of the Mn(+2) ion, and to determine the importance of spin assisted transitions in

Executive function and functional and structural brain differences in middle-age adults with autism spectrum disorder.

PubMed

Braden, B Blair; Smith, Christopher J; Thompson, Amiee; Glaspy, Tyler K; Wood, Emily; Vatsa, Divya; Abbott, Angela E; McGee, Samuel C; Baxter, Leslie C

2017-12-01

There is a rapidly growing group of aging adults with autism spectrum disorder (ASD) who may have unique needs, yet cognitive and brain function in older adults with ASD is understudied. We combined functional and structural neuroimaging and neuropsychological tests to examine differences between middle-aged men with ASD and matched neurotypical (NT) men. Participants (ASD, n = 16; NT, n = 17) aged 40-64 years were well-matched according to age, IQ (range: 83-131), and education (range: 9-20 years). Middle-age adults with ASD made more errors on an executive function task (Wisconsin Card Sorting Test) but performed similarly to NT adults on tests of delayed verbal memory (Rey Auditory Verbal Learning Test) and local visual search (Embedded Figures Task). Independent component analysis of a functional MRI working memory task (n-back) completed by most participants (ASD = 14, NT = 17) showed decreased engagement of a cortico-striatal-thalamic-cortical neural network in older adults with ASD. Structurally, older adults with ASD had reduced bilateral hippocampal volumes, as measured by FreeSurfer. Findings expand our understanding of ASD as a lifelong condition with persistent cognitive and functional and structural brain differences evident at middle-age. Autism Res 2017, 10: 1945-1959. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. We compared cognitive abilities and brain measures between 16 middle-age men with high-functioning autism spectrum disorder (ASD) and 17 typical middle-age men to better understand how aging affects an older group of adults with ASD. Men with ASD made more errors on a test involving flexible thinking, had less activity in a flexible thinking brain network, and had smaller volume of a brain structure related to memory than typical men. We will follow these older adults over time to determine if aging changes are greater for individuals with ASD. © 2017 International Society for Autism Research

Controllable spectrum artificial sunlight source system using LEDs with 32 different peak wavelengths of 385-910 nm.

PubMed

Fujiwara, Kazuhiro; Yano, Akira

2011-04-01

This study developed a lighting system that produces an approximate spectral irradiance (SI) of ground level sunlight in the wavelength range of 385-910 nm (GLS₃₈₅₋₉₁₀) using 547 light-emitting diodes (LEDs) with 32 different peak wavelengths. The produced SI can be modified over an arbitrary wavelength band. The SI at the light outlet reached up to 1/2 of the GLS₃₈₅₋₉₁₀ of a sunny April day, although the produced SI deviated from the GLS₃₈₅₋₉₁₀ at some wavelengths. For subsequent experiments, the reference SI was defined as 1/4 GLS₃₈₅₋₉₁₀ of a sunny April day. The SI produced from the lighting system was adjusted to approximate the reference SI. The ratios of the produced SI and the reference SI were within 0.72-1.28. As an application of the lighting system for biological studies, the transmitted SI of a green leaf of perilla (Perilla frutescens L.) was investigated. The curve shape of the transmitted SI, which had characteristically low transmission percentages of blue and red light, reflected the characteristics of the absorption spectra of chlorophylls. The lighting system is therefore potentially beneficial for use in diagnosing physiological conditions of plant leaves, although its application is not limited to plant physiological studies. Copyright © 2010 Wiley-Liss, Inc.

Spectrophotometry of six broad absorption line QSOs

NASA Technical Reports Server (NTRS)

Junkkarinen, Vesa T.; Burbidge, E. Margaret; Smith, Harding E.

1987-01-01

Spectrophotometric observations of six broad absorption-line QSOs (BALQSOs) are presented. The continua and emission lines are compared with those in the spectra of QSOs without BALs. A statistically significant difference is found in the emission-line intensity ratio for (N V 1240-A)/(C IV 1549-A). The median value of (N V)/(C IV) for the BALQSOs is two to three times the median for QSOs without BALs. The absorption features of the BALQSOs are described, and the column densities and limits on the ionization structure of the BAL region are discussed. If the dominant ionization mechanism is photoionization, then it is likely that either the ionizing spectrum is steep or the abundances are considerably different from solar. Collisional ionization may be a significant factor, but it cannot totally dominate the ionization rate.

Evaluating Sex and Age Differences in ADI-R and ADOS Scores in a Large European Multi-Site Sample of Individuals with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Tillmann, J.; Ashwood, K.; Absoud, M.; Bölte, S.; Bonnet-Brilhault, F.; Buitelaar, J. K.; Calderoni, S.; Calvo, R.; Canal-Bedia, R.; Canitano, R.; De Bildt, A.; Gomot, M.; Hoekstra, P. J.; Kaale, A.; McConachie, H.; Murphy, D. G.; Narzisi, A.; Oosterling, I.; Pejovic-Milovancevic, M.; Persico, A. M.; Puig, O.; Roeyers, H.; Rommelse, N.; Sacco, R.; Scandurra, V.; Stanfield, A. C.; Zander, E.; Charman, T.

2018-01-01

Research on sex-related differences in Autism Spectrum Disorder (ASD) has been impeded by small samples. We pooled 28 datasets from 18 sites across nine European countries to examine sex differences in the ASD phenotype on the ADI-R (376 females, 1763 males) and ADOS (233 females, 1187 males). On the ADI-R, early childhood restricted and…

Comparing Acquisition of AAC-Based Mands in Three Young Children with Autism Spectrum Disorder Using iPad® Applications with Different Display and Design Elements

ERIC Educational Resources Information Center

Gevarter, Cindy; O'Reilly, Mark F.; Rojeski, Laura; Sammarco, Nicolette; Sigafoos, Jeff; Lancioni, Giulio E.; Lang, Russell

2014-01-01

Augmentative and alternative communication (AAC) applications may differ in their use of display and design elements. Using a multielement design, this study compared mand acquisition in three preschool-aged males with autism spectrum disorder, across three different displays in two iPad® AAC applications. Displays included a Widgit symbol button…

A Multinational Study Examining the Cross Cultural Differences in Reported Symptoms of Autism Spectrum Disorders: Israel, South Korea, the United Kingdom, and the United States of America

ERIC Educational Resources Information Center

Matson, Johnny L.; Worley, Julie A.; Fodstad, Jill C.; Chung, Kyong-Mee; Suh, Dongsoo; Jhin, Hea Kyung; Ben-Itzchak, Esther; Zachor, Ditza A.; Furniss, Frederick

2011-01-01

Purportedly, there is a worldwide acceptance of diagnostic criteria for Autism Spectrum Disorders (ASD); however, cultural differences in regards to what is considered normal development may affect the diagnosis despite the biological basis for the condition. The aim of the current study was to examine the differences in reports of symptoms of ASD…

Feeling, caring, knowing: different types of empathy deficit in boys with psychopathic tendencies and autism spectrum disorder.

PubMed

Jones, Alice P; Happé, Francesca G E; Gilbert, Francesca; Burnett, Stephanie; Viding, Essi

2010-11-01

  Empathy dysfunction is one of the hallmarks of psychopathy, but it is also sometimes thought to characterise autism spectrum disorders (ASD). Individuals with either condition can appear uncaring towards others. This study set out to compare and contrast directly boys with psychopathic tendencies and boys with ASD on tasks assessing aspects of affective empathy and cognitive perspective taking. The main aim of the study was to assess whether a distinct profile of empathy deficits would emerge for boys with psychopathic tendencies and ASD, and whether empathy deficits would be associated with conduct problems in general, rather than psychopathic tendencies or ASD specifically.   Four groups of boys aged between 9 and 16 years (N = 96) were compared: 1) psychopathic tendencies, 2) ASD, 3) conduct problems and 4) comparison. Tasks were included to probe attribution of emotions to self, empathy for victims of aggression and cognitive perspective-taking ability.   Boys with psychopathic tendencies had a profile consistent with dysfunctional affective empathy. They reported experiencing less fear and less empathy for victims of aggression than comparison boys. Their cognitive perspective-taking abilities were not statistically significantly different from those of comparison boys. In contrast, boys with ASD had difficulties with tasks requiring cognitive perspective taking, but reported emotional experiences and victim empathy that were in line with comparison boys. Boys with conduct problems did not differ from comparison boys, suggesting that the affective empathy deficit seen in boys with psychopathic tendencies was specific to that group, rather than common to all boys with conduct problems.   Although both groups can appear uncaring, our findings suggest that the affective/information processing correlates of psychopathic tendencies and ASD are quite different. Psychopathic tendencies are associated with difficulties in resonating with other people

Feeling, caring, knowing: different types of empathy deficit in boys with psychopathic tendencies and autism spectrum disorder

PubMed Central

Jones, Alice P; Happé, Francesca GE; Gilbert, Francesca; Burnett, Stephanie; Viding, Essi

2010-01-01

Background Empathy dysfunction is one of the hallmarks of psychopathy, but it is also sometimes thought to characterise autism spectrum disorders (ASD). Individuals with either condition can appear uncaring towards others. This study set out to compare and contrast directly boys with psychopathic tendencies and boys with ASD on tasks assessing aspects of affective empathy and cognitive perspective taking. The main aim of the study was to assess whether a distinct profile of empathy deficits would emerge for boys with psychopathic tendencies and ASD, and whether empathy deficits would be associated with conduct problems in general, rather than psychopathic tendencies or ASD specifically. Methods Four groups of boys aged between 9 and 16 years (N = 96) were compared: 1) psychopathic tendencies, 2) ASD, 3) conduct problems and 4) comparison. Tasks were included to probe attribution of emotions to self, empathy for victims of aggression and cognitive perspective-taking ability. Results Boys with psychopathic tendencies had a profile consistent with dysfunctional affective empathy. They reported experiencing less fear and less empathy for victims of aggression than comparison boys. Their cognitive perspective-taking abilities were not statistically significantly different from those of comparison boys. In contrast, boys with ASD had difficulties with tasks requiring cognitive perspective taking, but reported emotional experiences and victim empathy that were in line with comparison boys. Boys with conduct problems did not differ from comparison boys, suggesting that the affective empathy deficit seen in boys with psychopathic tendencies was specific to that group, rather than common to all boys with conduct problems. Conclusions Although both groups can appear uncaring, our findings suggest that the affective/information processing correlates of psychopathic tendencies and ASD are quite different. Psychopathic tendencies are associated with difficulties in resonating

Sex differences in parent-reported executive functioning and adaptive behavior in children and young adults with autism spectrum disorder.

PubMed

White, Emily I; Wallace, Gregory L; Bascom, Julia; Armour, Anna C; Register-Brown, Kelly; Popal, Haroon S; Ratto, Allison B; Martin, Alex; Kenworthy, Lauren

2017-10-01

This study is the largest to date examining executive function and adaptive skills in females with autism spectrum disorder (ASD). Its primary aim was to utilize parent ratings of real-world executive functioning and adaptive behavior to better understand whether females with ASD differ from males with ASD in these areas of everyday functioning. We compared 79 females with ASD to 158 males with ASD (ages 7-18) who were statistically matched on age, IQ, and level of ADHD or ASD traits. All participants were assessed using the Behavior Rating Inventory of Executive Function (BRIEF) and a subset (56 females and 130 males) also received the Vineland Adaptive Behavior Scales (VABS). Females were rated by parents as having greater problems with executive function on the BRIEF. Parents also rated females as exhibiting more difficulties than males on the Daily Living Skills domain of the VABS. There was a correlation between increased global EF difficulty and decreased adaptive ability in both males and females. Our results indicate relative weaknesses for females compared to males diagnosed with ASD on executive function and daily living skills. These differences occur in the absence of sex differences in our sample in age, IQ, clinician ratings of core ASD symptomatology, parent ratings of ADHD symptoms, and parent-reported social and communication adaptive skills on the VABS. These findings indicate specific liabilities in real world EF and daily living skills for females with ASD and have important implications for targeting their treatments. Autism Res 2017, 10: 1653-1662. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

A Comparison of the Different Animal Models of Fetal Alcohol Spectrum Disorders and Their Use in Studying Complex Behaviors

PubMed Central

Patten, Anna R.; Fontaine, Christine J.; Christie, Brian R.

2014-01-01

Prenatal ethanol exposure (PNEE) has been linked to widespread impairments in brain structure and function. There are a number of animal models that are used to study the structural and functional deficits caused by PNEE, including, but not limited to invertebrates, fish, rodents, and non-human primates. Animal models enable a researcher to control important variables such as the route of ethanol administration, as well as the timing, frequency and amount of ethanol exposure. Each animal model and system of exposure has its place, depending on the research question being undertaken. In this review, we will examine the different routes of ethanol administration and the various animal models of fetal alcohol spectrum disorders (FASD) that are commonly used in research, emphasizing their strengths and limitations. We will also present an up-to-date summary on the effects of prenatal/neonatal ethanol exposure on behavior across the lifespan, focusing on learning and memory, olfaction, social, executive, and motor functions. Special emphasis will be placed where the various animal models best represent deficits observed in the human condition and offer a viable test bed to examine potential therapeutics for human beings with FASD. PMID:25232537

Language and emotional abilities in children with Williams syndrome and children with autism spectrum disorder: similarities and differences

PubMed Central

Lacroix, Agnès; Famelart, Nawelle; Guidetti, Michèle

2016-01-01

Williams syndrome (WS) is a genetic disease with a relatively homogeneous profile: relatively well-preserved language, impaired cognitive activities, and hypersociability. Autism spectrum disorder (ASD) refers to a group of individuals with impairments in aspects of communication and a particular pattern of language acquisition. Although ASD and WS are polar opposites when it comes to communication abilities (language and emotion) and social behavior, comparisons between WS and ASD are still rare in the literature. ASD and WS are both associated with general language and developmental delays. Difficulties in social interaction and general pragmatic difficulties are reported in both ASD and WS, but are more pervasive in ASD. Regarding facial emotion recognition, the two syndromes differ markedly in sensitivity to human faces. Despite the heterogeneity of these two groups, only a few studies with children have paid sufficient attention to participant recruitment and study design. A number of aspects need to be taken into account (eg, small age range, homogeneity of the subgroups, matching with typically developing children) if scientific results are to inform the design of intervention programs for children with neurodevelopmental disorders such as ASD and WS. PMID:29388584

Preliminary evidence that different mechanisms underlie the anger superiority effect in children with and without Autism Spectrum Disorders

PubMed Central

Isomura, Tomoko; Ogawa, Shino; Yamada, Satoko; Shibasaki, Masahiro; Masataka, Nobuo

2014-01-01

Previous studies have demonstrated that angry faces capture humans' attention more rapidly than emotionally positive faces. This phenomenon is referred to as the anger superiority effect (ASE). Despite atypical emotional processing, adults and children with Autism Spectrum Disorders (ASD) have been reported to show ASE as well as typically developed (TD) individuals. So far, however, few studies have clarified whether or not the mechanisms underlying ASE are the same for both TD and ASD individuals. Here, we tested how TD and ASD children process schematic emotional faces during detection by employing a recognition task in combination with a face-in-the-crowd task. Results of the face-in-the-crowd task revealed the prevalence of ASE both in TD and ASD children. However, the results of the recognition task revealed group differences: In TD children, detection of angry faces required more configural face processing and disrupted the processing of local features. In ASD children, on the other hand, it required more feature-based processing rather than configural processing. Despite the small sample sizes, these findings provide preliminary evidence that children with ASD, in contrast to TD children, show quick detection of angry faces by extracting local features in faces. PMID:24904477

Reduction effect of surface temperature of baked bricks with different pore shapes during absorption-evaporation test

NASA Astrophysics Data System (ADS)

Oguchi, Chiaki T.; Shinozuka, Katsumi

2017-04-01

To study the effect of decreasing in surface temperature of baked bricks with various pore shapes, the present study performed several experiments such as water absorbance test and heating test. For the preparation of experimental specimens, bricks with artificial spherical pores, artificial linear pores and non-additional artificial pores were made. The bricks were examined their properties of bulk density, Equotip hardness and absorbing properties by putting in the water. Wet bricks were also put in the incubator set at 50 °C, and monitored the increasing of surface temperature of each brick. Brick with linear pores shows higher water absorption rate in a short time than those with spherical pores. They evaporated moisture faster than those with a spherical pores. They kept the temperature by 11.7 °C lower than the setting temperature, whereas the bricks with a spherical pores kept the temperature by 10.5 °C . Bricks with linear pores has about 10% higher effectiveness of decreasing in surface temperature than those with spheroidal pores.

Adam, Eve and the reflux enigma: age and sex differences across the gastro-oesophageal reflux spectrum.

PubMed

Royston, Christine; Bardhan, Karna D

2017-06-01

We present demographic differences across the gastro-oesophageal reflux disease (GORD) spectrum in a UK District General Hospital. Data were prospectively collected over 37 years. At endoscopy patients were categorized as: erosive oesophagitis (EO), Barrett's oesophagus (BO) or nonerosive reflux disease (NER). Analysis 1: comparison of EO, BO and NER 1977-2001 when the database for GORD without BO closed. Analysis 2: demographic differences in oesophageal adenocarcinoma (OAC) in total BO population diagnosed 1977-2011. GORD 1977-2001 (n=11 944): sex, male predominance in EO and BO but not NER; male : female ratios, 1.81, 1.65, 0.87, respectively (P<0.0001); mean age at presentation, EO 54 years, BO 62 years, NER 50 years; women were older than men by 10, 7 and 6 years, respectively.BO 1977-2011: prevalent OAC, 87/1468 (6%); male : female ratio, 4.1 (P<0.0001); incident OAC, 54/1381 (3.9%); male : female ratio, 3.5 (P<0.0001). Among all BO, more men developed OAC (3 vs. 0.9%). Within each sex, proportion of OAC higher among men (4.9 vs. 2.3%); at OAC diagnosis women were slightly but not significantly older (69.9 vs. 72.3 years, P=0.322). Two views may explain our findings. First, women have either milder reflux, or reduced mucosal sensitivity hence reflux remains silent for longer. Alternatively, women genuinely develop reflux later, that is, are more protected and for longer from developing GORD and its complications. Early evidence is emerging that female sex hormones may indeed have a protective role in GORD during the reproductive period. We suggest reflux and its consequences may be an example of 'protection' conferred on Eve.

Differences in age-dependent neural correlates of semantic processing between youths with autism spectrum disorder and typically developing youths.

PubMed

Chen, Pin-Jane; Gau, Susan Shur-Fen; Lee, Shu-Hui; Chou, Tai-Li

2016-12-01

Individuals with autism spectrum disorders (ASD) have aberrant neural activity during semantic judgments. We aimed to examine age-dependent neural correlates of semantic processing in boys with ASD as compared to typically developing boys (TD). We used functional MRI to investigate 37 boys with ASD (mean age = 13.3 years, standard deviation = 2.4) and 35 age-, sex-, Intelligence quotient (IQ)- and handedness-matched TD boys (mean age = 13.3 years, standard deviation = 2.7) from age 8 to 18 years. Participants had to indicate whether pairs of Chinese characters presented visually were related in meaning. Group (ASD, TD) × Age (Old, Young) ANOVA was used to examine the difference of age-related changes. Direct comparisons between the adolescent group and the child group were also performed. The behavioral results showed that the ASD group had lower accuracy in the related condition relative to the TD group. The neuroimaging results showed greater activation in the cuneus and less activation in the left inferior frontal gyrus in boys with ASD than TD boys. Children with ASD produced greater activation in the cuneus than TD children. Adolescents with ASD showed reduced left IFG activation as compared to TD adolescents. Our findings suggest that TD boys may engage more in higher-level processing of retrieving or selecting semantic features while boys with ASD may rely more on lower-level visual processing during semantic judgments. The findings imply different functional organizations of the semantic system between the two groups. Autism Res 2016, 9: 1263-1273. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Age Differences in Energy Absorption in the Upper Extremity During a Descent Movement: Implications for Arresting a Fall

PubMed Central

Stotz, Paula J.; Normandin, Sarah C.; Robinovitch, Stephen N.

2010-01-01

Background Falls are the number one cause of unintentional injury in older adults. The protective response of “breaking the fall” with the outstretched hand is often essential for avoiding injury to the hip and head. In this study, we compared the ability of young and older women to absorb the impact energy of a fall in the outstretched arms. Methods Twenty young (mean age = 21 years) and 20 older (M = 78 years) women were instructed to slowly lower their body weight, similar to the descent phase of a push-up, from body lean angles ranging from 15° to 90°. Measures were acquired of peak upper extremity energy absorption, arm deflection, and hand contact force. Results On average, older women were able to absorb 45% less energy in the dominant arm than young women (1.7 ± 0.5% vs 3.1 ± 0.4% of their body weight × body height; p < .001). These results suggest that, even when both arms participate equally, the average energy content of a forward fall exceeds by 5-fold the average energy that our older participants could absorb and exceeds by 2.7-fold the average energy that young participants could absorb. Conclusions During a descent movement that simulates fall arrest, the energy-absorbing capacity of the upper extremities in older women is nearly half that of young women. Absorbing the full energy of a fall in the upper extremities is a challenging task even for healthy young women. Strengthening of upper extremity muscles should enhance this ability and presumably reduce the risk for injury to the hip and head during a fall. PMID:19861641

Age differences in energy absorption in the upper extremity during a descent movement: implications for arresting a fall.

PubMed

Sran, Meena M; Stotz, Paula J; Normandin, Sarah C; Robinovitch, Stephen N

2010-03-01

Falls are the number one cause of unintentional injury in older adults. The protective response of "breaking the fall" with the outstretched hand is often essential for avoiding injury to the hip and head. In this study, we compared the ability of young and older women to absorb the impact energy of a fall in the outstretched arms. Twenty young (mean age = 21 years) and 20 older (M = 78 years) women were instructed to slowly lower their body weight, similar to the descent phase of a push-up, from body lean angles ranging from 15 degrees to 90 degrees . Measures were acquired of peak upper extremity energy absorption, arm deflection, and hand contact force. On average, older women were able to absorb 45% less energy in the dominant arm than young women (1.7 +/- 0.5% vs 3.1 +/- 0.4% of their body weight x body height; p < .001). These results suggest that, even when both arms participate equally, the average energy content of a forward fall exceeds by 5-fold the average energy that our older participants could absorb and exceeds by 2.7-fold the average energy that young participants could absorb. During a descent movement that simulates fall arrest, the energy-absorbing capacity of the upper extremities in older women is nearly half that of young women. Absorbing the full energy of a fall in the upper extremities is a challenging task even for healthy young women. Strengthening of upper extremity muscles should enhance this ability and presumably reduce the risk for injury to the hip and head during a fall.

ABSORPTION MEASURE DISTRIBUTION IN Mrk 509

SciTech Connect

Adhikari, T. P.; Różańska, A.; Sobolewska, M.

2015-12-20

In this paper we model the observed absorption measure distribution (AMD) in Mrk 509, which spans three orders of magnitude in ionization level with a single-zone absorber in pressure equilibrium. AMD is usually constructed from observations of narrow absorption lines in radio-quiet active galaxies with warm absorbers. We study the properties of the warm absorber in Mrk 509 using recently published broadband spectral energy distribution observed with different instruments. This spectrum is an input in radiative transfer computations with full photoionization treatment using the titan code. We show that the simplest way to fully reproduce the shape of AMD is tomore » assume that the warm absorber is a single zone under constant total pressure. With this assumption, we found theoretical AMD that matches the observed AMD determined on the basis of the 600 ks reflection grating spectrometer XMM-Newton spectrum of Mrk 509. The softness of the source spectrum and the important role of the free–free emission breaks the usual degeneracy in the ionization state calculations, and the explicit dependence of the depths of AMD dips on density open a new path to the density diagnostic for the warm absorber. In Mrk 509, the implied density is of the order of 10{sup 8} cm{sup −3}.« less

Measurement of 241Am-Be spectra (bare and Pb-covered) using TLD pairs in multi-spheres: Spectrum unfolding by different methods

NASA Astrophysics Data System (ADS)

Tripathy, S. P.; Bakshi, A. K.; Sathian, V.; Tripathi, S. M.; Vega-carrillo, H. R.; Nandy, M.; Sarkar, P. K.; Sharma, D. N.

2009-01-01

The neutron spectra from a Pb-covered and a bare (without Pb-cover) 241Am-Be (α,n) source were measured using thermoluminescent detector (TLD) pairs of 6LiF and 7LiF with high-density polyethylene (HDPE) multi-spheres of seven different diameters. A total of 8 distinct neutron response signals (including a bare mode exposure) were obtained from which the energy distribution for the entire energy range was generated with the help of different neutron spectrum unfolding methods, viz. BUNKI, BUNKIUT and Frascati unfolding interactive tool (FRUIT). Shape of these spectra are matching very well and is also comparable with the standard IAEA 241Am-Be spectrum, thus, validating the unfolding methods used in this work. The effect of Pb-cover on the spectrum and the unfolding details are reported in the paper.

[Effects of different nitrogen application rates on 15N-urea absorption, utilization, loss and fruit yield and quality of dwarf apple].

PubMed

Chen, Qian; Ding, Ning; Peng, Ling; Ge, Shun Feng; Jiang, Yuan Mao

2017-07-18

Seven-year-old 'Yanfu3'/M 26 /M. hupehensis Rehd. seedlings and 15 N trace technique were used to explore the characteristics of 15 N-urea absorption, utilization, loss and fruit yield and quality under different nitrogen application rates (N 100 , N 200 and N 300 ). The main results were as follows: the plant growth, 15 N absorption, utilization and loss differed significantly under different treatments. The plant leaf chlorophyll content (SPAD value), photosynthetic rate (P n ), total N content of leaves and the biomass, as well as the root-shoot ratio of N 200 treatment were obviously higher than the N 100 and N 300 treatments. Significant differences were observed in the 15 N derived from fertilizer (Ndff value) of different organs under different nitrogen application rates. The Ndff of fruits (flowers), leaves, one-year-old branch, and perennial branches in each measurement period was N 100 >N 200 ＞N 300 , while that of the roots at full-bloom and spring shoot growing slowly stage was N 100 >N 200 ＞N 300 , and in a trend of N 200 >N 100 ＞N 300 at autumn shoot growing stage, fruit rapid-swel-ling stage and fruit maturity stage. At fruit maturity stage, plant 15 N nitrogen utilization ratio of N 200 treatment was 23.6%, which was obviously higher than the N 100 (16.3%) and N 300 (14.4%) treatments, with the 15 N loss rate of 56.4%, obviously lower than the N 100 (60.6%) and N 300 (66.1%) treatments. There were significant differences among the treatments in fruit mass, yield per plant, soluble solid, fruit firmness, soluble sugar, titratable acids and sugar-acid ratio of different nitrogen rates, and the N 200 treatment showed the best performance, followed by the N 300 treatment, and then the N 100 treatment.

Differences in Copper Absorption and Accumulation between Copper-Exclusion and Copper-Enrichment Plants: A Comparison of Structure and Physiological Responses

PubMed Central

Fu, Lei; Chen, Chen; Wang, Bin; Zhou, Xishi; Li, Shuhuan; Guo, Pan; Shen, Zhenguo; Wang, Guiping; Chen, Yahua

2015-01-01

Differences in copper (Cu) absorption and transport, physiological responses and structural characteristics between two types of Cu-resistant plants, Oenothera glazioviana (Cu-exclusion type) and Elsholtzia haichowensis (Cu-enrichment type), were investigated in the present study. The results indicated the following: (1) After 50 μM Cu treatment, the Cu ratio in the xylem vessels of E. haichowensis increased by 60%. A Cu adsorption experiment indicated that O. glazioviana exhibited greater resistance to Cu, and Cu absorption and the shoot/root ratio of Cu were significantly lower in O. glazioviana than in E. haichowensis. (2) An analysis of the endogenous abscisic acid (ABA) variance and exogenous ABA treatment demonstrated that the ABA levels of both plants did not differ; exogenous ABA treatment clearly reduced Cu accumulation in both plants. (3) The leaf stomatal density of O. glazioviana was significantly less than that of E. haichowensis. Guard cells in E. haichowensis plants were covered with a thick cuticle layer, the epidermal hair was more numerous and longer, and the number of xylem conduits in the root was small. (4) The transpiration rate and the stomatal conductance of O. glazioviana were both significantly lower than those of E. haichowensis, regardless of whether the plants were treated with Cu. Taken together, these results indicate that the differences in the structural characteristics between these two plant species, particularly in the characteristics related to plant transpiration, are important factors that govern whether plants acquire or exclude Cu. PMID:26207743

Differences in Copper Absorption and Accumulation between Copper-Exclusion and Copper-Enrichment Plants: A Comparison of Structure and Physiological Responses.

PubMed

Fu, Lei; Chen, Chen; Wang, Bin; Zhou, Xishi; Li, Shuhuan; Guo, Pan; Shen, Zhenguo; Wang, Guiping; Chen, Yahua

2015-01-01

Differences in copper (Cu) absorption and transport, physiological responses and structural characteristics between two types of Cu-resistant plants, Oenothera glazioviana (Cu-exclusion type) and Elsholtzia haichowensis (Cu-enrichment type), were investigated in the present study. The results indicated the following: (1) After 50 μM Cu treatment, the Cu ratio in the xylem vessels of E. haichowensis increased by 60%. A Cu adsorption experiment indicated that O. glazioviana exhibited greater resistance to Cu, and Cu absorption and the shoot/root ratio of Cu were significantly lower in O. glazioviana than in E. haichowensis. (2) An analysis of the endogenous abscisic acid (ABA) variance and exogenous ABA treatment demonstrated that the ABA levels of both plants did not differ; exogenous ABA treatment clearly reduced Cu accumulation in both plants. (3) The leaf stomatal density of O. glazioviana was significantly less than that of E. haichowensis. Guard cells in E. haichowensis plants were covered with a thick cuticle layer, the epidermal hair was more numerous and longer, and the number of xylem conduits in the root was small. (4) The transpiration rate and the stomatal conductance of O. glazioviana were both significantly lower than those of E. haichowensis, regardless of whether the plants were treated with Cu. Taken together, these results indicate that the differences in the structural characteristics between these two plant species, particularly in the characteristics related to plant transpiration, are important factors that govern whether plants acquire or exclude Cu.

Laser Irradiated Foam Targets: Absorption and Radiative Properties

NASA Astrophysics Data System (ADS)

Salvadori, Martina; Luigi Andreoli, Pier; Cipriani, Mattia; Consoli, Fabrizio; Cristofari, Giuseppe; De Angelis, Riccardo; di Giorgio, Giorgio; Giulietti, Danilo; Ingenito, Francesco; Gus'kov, Sergey Yu.; Rupasov, Alexander A.

2018-01-01

An experimental campaign to characterize the laser radiation absorption of foam targets and the subsequent emission of radiation from the produced plasma was carried out in the ABC facility of the ENEA Research Center in Frascati (Rome). Different targets have been used: plastic in solid or foam state and aluminum targets. The activated different diagnostics allowed to evaluate the plasma temperature, the density distribution, the fast particle spectrum and the yield of the X-Ray radiation emitted by the plasma for the different targets. These results confirm the foam homogenization action on laser-plasma interaction, mainly attributable to the volume absorption of the laser radiation propagating in such structured materials. These results were compared with simulation absorption models of the laser propagating into a foam target.

Binge Eating Disorder and Bipolar Spectrum disorders in obesity: Psychopathological and eating behaviors differences according to comorbidities.

PubMed

Segura-Garcia, Cristina; Caroleo, Mariarita; Rania, Marianna; Barbuto, Elvira; Sinopoli, Flora; Aloi, Matteo; Arturi, Franco; De Fazio, Pasquale

2017-01-15

Obesity is not a mental disorder, yet DSM-5 recognizes a strong association between obesity and psychiatric syndromes. Disorders within the Bipolar Spectrum (BSD) and Binge Eating Disorder (BED) are the most frequent psychiatric disorders among obese patients. The aim of this research is to investigate the psychopathological differences and the distinctive eating behaviors that accompany these comorbidities in obese patients. One hundred and nineteen obese patients (40 males; 79 females) underwent psychological evaluation and psychiatric interview, and a dietitian evaluated their eating habits. Patients were divided into four groups according to comorbidities, and comparisons were run accordingly. Forty-one percent of participants presented BED+BSD comorbidity (Group 1), 21% BED (Group 2) and 8% BSD (Group 3); only 29% obese participants had no comorbidity (Group 4). Female gender was overrepresented among Groups 1 and 2. BSD diagnosis varied according to comorbidities: Type II Bipolar Disorder and Other Specified and Related Bipolar Disorder (OSR BD) were more frequent in Group 1 and Type I Bipolar Disorder in Group 3. A trend of decreasing severity in eating behaviors and psychopathology was evident according to comorbidities (Group 1=Group2>Group3>Group 4). Limitations include the small sample size and the cross-sectional design of the study. BED and BSD are frequent comorbidities in obesity. Type II Bipolar Disorder and OSR BD are more frequent in the group with double comorbidity. The double comorbidity seems associated to more severe eating behaviors and psychopathology. Distinctive pathological eating behaviors could be considered as warning signals, symptomatic of psychiatric comorbidities in Obesity. Copyright © 2016 Elsevier B.V. All rights reserved.

Spectrum of Enterovirus Serotypes Causing Uncomplicated Hand, Foot, and Mouth Disease and Enteroviral diagnostic yield of different clinical samples.

PubMed

Gao, Lidong; Zou, Gang; Liao, Qiaohong; Zhou, Yonghong; Liu, Fengfeng; Dai, Bingbing; Liu, Jia; Chen, Zhiyong; Xing, Weijia; Yang, Le; Liang, Hong; Zhang, Yi; Chen, Zhenhua; Luo, Li; Li, Qing; Luo, Kaiwei; Wu, Peng; Mo, Xiaowei; Wang, Lili; Lan, Ke; Horby, Peter W; Cowling, Benjamin J; Simmonds, Peter; Altmeyer, Ralf; van Doorn, H Rogier; Yu, Hongjie

2018-04-24

Hand, foot, and mouth disease (HFMD) represents a substantial disease burden in the Western Pacific region. We investigated the spectrum of causative enteroviruses of HFMD, and evaluated different clinical samples' diagnostic yield for enteroviruses. We enrolled pediatric patients hospitalized for HFMD among six hospitals in Anhua County, Hunan Province, China between October 2013 and September 2016. Throat swabs and stool samples (or rectal swabs) were collected to detect the enterovirus serotypes by real time RT-PCR or nested PCR. Among the 2,836 patients only one developed severe illness. Seventeen serotypes were identified in 2,401 patients (85%), with the most frequently detected being CV-A16 (29%, 814), CV-A6 (28%, 784), EV-A71 (17%, 491), CV-A10 (4%, 114), and CV-A4 (2%, 53). Children were younger in CV-A6, CV-A10, and CV-A4 infections (median 12 months, IQR 12-24 months) than EV-A71 and CV-A16 infections (median 24 months, IQR 12-36 months, p<0.05). Annual peaks of HFMD hospitalization occurred during April-June. The predominant enterovirus serotype shifted between CV-A16 and CV-A6 during the three years. Stool had a higher diagnostic yield (89%) than rectal (79%) and throat swabs (74%). Detection rates reached 93% when testing stools followed by throat swabs if stools were negative, and 89% when testing rectal swabs followed by throat swabs if rectal swabs were negative. Our results provide a virological benchmark for future surveillance and diagnostics. Continuous comprehensive virological surveillance is essential, especially after implementation of the EV-A71 vaccine in China, to monitor serotype replacement and the impact of EV-A71 vaccine.

Cross Cultural Differences in Challenging Behaviors of Children with Autism Spectrum Disorders: An International Examination between Israel, South Korea, the United Kingdom, and the United States of America

ERIC Educational Resources Information Center

Chung, Kyong-Mee; Jung, Woohyun; Yang, Jae-won; Ben-Itzchak, Esther; Zachor, Ditza A.; Furniss, Frederick; Heyes, Katie; Matson, Johnny L.; Kozlowski, Alison M.; Barker, Alyse A.

2012-01-01

Challenging behaviors are deemed extremely common within the autism spectrum disorders (ASD) population. Numerous factors and their effects upon the presence and severity of challenging behaviors within this population have been investigated. However, there has been limited research to investigate the effects of cultural differences on challenging…

Do Social Networks Differ? Comparison of the Social Networks of People with Intellectual Disabilities, People with Autism Spectrum Disorders and Other People Living in the Community

ERIC Educational Resources Information Center

van Asselt-Goverts, A. E.; Embregts, P. J. C. M.; Hendriks, A. H. C.; Wegman, K. M.; Teunisse, J. P.

2015-01-01

The aim of this study was to determine the similarities and differences in social network characteristics, satisfaction and wishes with respect to the social network between people with mild or borderline intellectual disabilities (ID), people with autism spectrum disorders (ASD) and a reference group. Data were gathered from 105 young adults…

Divergence of Age-Related Differences in Social-Communication: Improvements for Typically Developing Youth but Declines for Youth with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Wallace, Gregory L.; Dudley, Katerina; Anthony, Laura; Pugliese, Cara E.; Orionzi, Bako; Clasen, Liv; Lee, Nancy Raitano; Giedd, Jay N.; Martin, Alex; Raznahan, Armin; Kenworthy, Lauren

2017-01-01

Although social-communication difficulties and repetitive behaviors are hallmark features of autism spectrum disorder (ASD) and persist across the lifespan, very few studies have compared age-related differences in these behaviors between youth with ASD and same-age typically developing (TD) peers. We examined this issue using SRS-2 (Social…

Observation of Classroom Social Communication: Do Children with Fetal Alcohol Spectrum Disorders Spend Their Time Differently than Their Typically Developing Peers?

ERIC Educational Resources Information Center

Olswang, Lesley B.; Svensson, Liselotte; Astley, Susan

2010-01-01

Purpose: In this research, the authors examined how social communication profiles during classroom activities differed between children with fetal alcohol spectrum disorders (FASD) and typically developing pair-matched peers. Method: Twelve pairs of children were observed in their classrooms 20 min a day for 4 days across 2 weeks. Coders…

Maternal Perceptions of Nutrition, Stress, Time, and Assistance during Mealtimes: Similarities and Differences between Mothers of Children with Autism Spectrum Disorders and Mothers of Children with Typical Development

ERIC Educational Resources Information Center

Crowe, Terry K.; Freeze, Brenna; Provost, Elizabeth; King, Lauriann; Sanders, Margaret

2016-01-01

This study examined similarities and differences between mothers of preschool children with autism spectrum disorders (ASD) and mothers of preschool children with typical development (TD) in their perceptions of four mealtime outcomes: nutritional intake, stress, time, and assistance given. One group of 24 mothers of children with ASD and one…

Gender and Geographic Differences in the Prevalence of Autism Spectrum Disorders in Children: Analysis of Data from the National Disability Registry of Taiwan

ERIC Educational Resources Information Center

Lai, Der-Chung; Tseng, Yen-Cheng; Hou, Yuh-Ming; Guo, How-Ran

2012-01-01

The prevalence of autism spectrum disorders (ASD) in the world has increased dramatically in the recent decades. However, data at the national level are limited, and geographic differences are seldom evaluated. According to the law, the local governments in Taiwan began to certify disabled residents and provide various services in 1980, and the…

Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: A multivariate study

NASA Astrophysics Data System (ADS)

Arain, Salma Aslam; Kazi, Tasneem G.; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

2014-12-01

An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu2+) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu2+ using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046 μg L-1 and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu2+ in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu2+ in serum samples of different viral hepatitis patients and healthy controls.

Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: a multivariate study.

PubMed

Arain, Salma Aslam; Kazi, Tasneem G; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

2014-12-10

An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu(2+)) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu(2+) using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046μgL(-1) and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu(2+) in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu(2+) in serum samples of different viral hepatitis patients and healthy controls. Copyright © 2014 Elsevier B.V. All rights reserved.

Oxytocin and vasopressin in children and adolescents with autism spectrum disorders: Sex differences and associations with symptoms

PubMed Central

Miller, Meghan; Bales, Karen L.; Taylor, Sandra L.; Yoon, Jong; Hostetler, Caroline M.; Carter, Cameron S.; Solomon, Marjorie

2012-01-01

There has been intensified interest in the neuropeptides oxytocin (OT) and arginine vasopressin (AVP) in autism spectrum disorders (ASD) given their role in affiliative and social behavior in animals, positive results of treatment studies using OT, and findings that genetic polymorphisms in the AVP-OT pathway are present in individuals with ASD. Nearly all such studies in humans have focused only on males. With this preliminary study, we provide basic and novel information on the involvement of OT and AVP in autism with an investigation of blood plasma levels of these neuropeptides in 75 preadolescent and adolescent girls and boys ages 8–18: 40 with high-functioning ASD (19 girls, 21 boys) and 35 typically developing children (16 girls, 19 boys). We related neuropeptide levels to social, language, repetitive behavior, and internalizing symptom measures in these individuals. There were significant gender effects: Girls showed higher levels of OT while boys had significantly higher levels of AVP. There were no significant effects of diagnosis on OT or AVP. Higher OT values were associated with greater anxiety in all girls and with better pragmatic language in all boys and girls. AVP levels were positively associated with restricted and repetitive behaviors in girls with ASD but negatively (non-significantly) associated with these behaviors in boys with ASD. Our results challenge the prevailing view that plasma OT levels are lower in individuals with ASD and suggest there are distinct and sexually dimorphic mechanisms of action for OT and AVP underlying anxiety and repetitive behaviors. Lay Abstract Oxytocin (OT) and arginine vasopressin (AVP) are neuropeptides that are involved in affiliative and social behavior. Previous studies have shown that boys with autism spectrum disorders (ASD) have lower levels of OT than boys without ASD, and treatment studies have found that intranasal infusions of OT increase social behaviors in mostly males with ASD. With this study

Spectrum of Transient ASASSN-13at

NASA Astrophysics Data System (ADS)

Garnavich, Peter; Deal, Shanel

2013-06-01

We observed the transient ASASSN-13at (ATEL 5168) on June 28.3 (UT) with the Vatican Advanced Technology Telescope (VATT) and VATTSPEC instrument. The resulting spectrum covers the wavelength range between 365 nm and 750 nm with a resolution of 1100. The spectrum of ASASSN-13at shows a blue continuum with strong Balmer absorption lines. Helium absorption at 447 nm and 588 nm is also seen. Blue-shifted emission lines are visible within the Halpha and Hbeta absorption features.

Quasar Absorption Studies

NASA Technical Reports Server (NTRS)

Mushotzky, Richard (Technical Monitor); Elvis, Martin

2004-01-01

The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

Research of the NH3 Lines in the Region λ 6475 Å Band of Jupiter Spectrum

NASA Astrophysics Data System (ADS)

Atai, Adalat; Mikailov, Khidir Mustafa; Farziyev, Zabit

Context. In 2014, spectral observations of separate areas on the disk of Jupiter in the visible spectrum were made by means of the echelle-spectrometer installed in Cassegrain 2-meter mirror telescope's focus of Shamakhi Astrophysical Observatory. The echellespectrometer equipped with the CCD camera provided spectral resolution R=14000 with dispersion of 10 Å/mm. Aims. Features of the intensity change of the ammonia absorption lines at 6475 Å were studied for the spectra of different details of Jupiter's disk. The absorption line 6495.7 Å for ammonia was found only in the GRS spectrum of Jupiter. Methods. Earlier that line was noted in the laboratory spectrum of Giver; it was absent in the spectrum obtained by Mason; in the theoretical spectrum of ammonia it was noted at 6495.9 Å. Comparison of characteristics of the ammonia line in the spectra of various details allows investigating horizontal inhomogeneity of ammonia distribution on the Jupiter's disk. Results.

The difference in medical utilization and associated factors between children and adolescents with and without autism spectrum disorders.

PubMed

Wu, Ching-Mien; Kung, Pei-Tseng; Li, Chia-Ing; Tsai, Wen-Chen

2014-10-18

This study determined differences in health care utilization and health care expenditures between children with and without autism spectrum disorder (ASD) and examined possible reasons for these differences. A retrospective longitudinal study of children aged younger than 18 years both with and without ASD was conducted using the 2008 database of the Ministry of the Interior registry of the disabled persons in tandem with the National Health Insurance Research Database. Propensity score matching for the covariates of age, sex, and parental monthly salary was used to match children at a ratio of 1:3 for observing health care utilization among children with and without ASD from 2008 to 2011. Generalized estimating equation analysis was performed to determine factors that affect health care utilization, such as physician visits, emergency room (ER) visits, hospitalizations, and health care expenditures. After matching was completed, the sample size comprised 3280 children with ASD and 9840 children without ASD. Among the children in the sample, most were boys (86.68%) between the ages of 6-11 years, and the average age of both samples was 9.8 years. After relevant factors were controlled for, the children with ASD yielded an average of 14.2 more annual physician visits and were more likely to visit the ER (OR=1.12, P<.05) or be hospitalized (OR=1.48; P<.05) compared with the children without ASD. Compared with the children without ASD, the children with ASD exhibited higher annual physician visit expenditures (NT$26,580 more), higher ER visit expenditures (NT$50 more), higher hospitalization expenditures (NT$5830 more), and NT$32,460 more total health care expenditures (all P<.05). Significant predictors of health care expenditures among the children with ASD were age, parental monthly salary, and severity of comorbidity. The most common reasons for physician visits or hospitalizations among the children with ASD were psychiatric illnesses, respiratory illnesses, and

Differences in Neural Correlates of Speech Perception in 3 Month Olds at High and Low Risk for Autism Spectrum Disorder

ERIC Educational Resources Information Center

Edwards, Laura A.; Wagner, Jennifer B.; Tager-Flusberg, Helen; Nelson, Charles A.

2017-01-01

In this study, we investigated neural precursors of language acquisition as potential endophenotypes of autism spectrum disorder (ASD) in 3-month-old infants at high and low familial ASD risk. Infants were imaged using functional near-infrared spectroscopy while they listened to auditory stimuli containing syllable repetitions; their neural…

Feeling, Caring, Knowing: Different Types of Empathy Deficit in Boys with Psychopathic Tendencies and Autism Spectrum Disorder

ERIC Educational Resources Information Center

Jones, Alice P.; Happe, Francesca G. E.; Gilbert, Francesca; Burnett, Stephanie; Viding, Essi

2010-01-01

Background: Empathy dysfunction is one of the hallmarks of psychopathy, but it is also sometimes thought to characterise autism spectrum disorders (ASD). Individuals with either condition can appear uncaring towards others. This study set out to compare and contrast directly boys with psychopathic tendencies and boys with ASD on tasks assessing…

Differences in Praxis Performance and Receptive Language during Fingerspelling between Deaf Children with and without Autism Spectrum Disorder

ERIC Educational Resources Information Center

Bhat, Anjana N.; Srinivasan, Sudha M.; Woxholdt, Colleen; Shield, Aaron

2018-01-01

Children with autism spectrum disorder present with a variety of social communication deficits such as atypicalities in social gaze and verbal and non-verbal communication delays as well as perceptuo-motor deficits like motor incoordination and dyspraxia. In this study, we had the unique opportunity to study praxis performance in deaf children…

Different Responses to Trauma in Two Children with Autistic Spectrum Disorder: The Mouth as Crossroads for the Sense of Self

ERIC Educational Resources Information Center

Rhode, Maria

2004-01-01

Two contrasting cases are discussed of boys with autistic spectrum disorder who had suffered cumulative trauma. Although their material was similar in many respects, the 9-year-old made excellent progress during therapy, while the 4-year-old developed much less in spite of being in intensive treatment. This contrast is discussed with regard to…

Executive Functioning Differences between Adults with Attention Deficit Hyperactivity Disorder and Autistic Spectrum Disorder in Initiation, Planning and Strategy Formation

ERIC Educational Resources Information Center

Bramham, Jessica; Ambery, Fiona; Young, Susan; Morris, Robin; Russell, Ailsa; Xenitidis, Kiriakos; Asherson, Philip; Murphy, Declan

2009-01-01

Executive functioning deficits characterize the neuropsychological profiles of the childhood neurodevelopmental disorders of attention deficit hyperactivity disorder (ADHD) and autistic spectrum disorder (ASD). This study sought to determine whether similar impairments exist in adults with ADHD (N = 53) and ASD (N = 45) in comparison with a…

Effect of time period after boric acid injection on 10B absorption in different regions of adult male rat's brain.

PubMed

Khojasteh, Nasrin Baghban; Pazirandeh, Ali; Jameie, Behnam; Goodarzi, Samereh

2012-06-01

Distribution of (10)B in different regions of rat normal brain was studied. Two groups were chosen as control and trial. Trial group received 2 ml of neutral boron compound. 2, 4 and 6 h after the injection brain removed, coronal sections of forebrain, midbrain and hindbrain were sandwiched between two pieces of polycarbonate. Autoradiography plots of (10)B distribution showed significant differences in three regions with the highest (10)B concentration in the forebrain during 4 h after injection. Copyright © 2012 Elsevier Ltd. All rights reserved.

Percutaneous absorption

PubMed Central

Brisson, Paul

1974-01-01

Clinical effectiveness of topically applied medications depends on the ability of the active ingredient to leave its vehicle and penetrate into the epidermis. The stratum corneum is that layer of the epidermis which functionally is the most important in limiting percutaneous absorption, showing the characteristics of a composite semipermeable membrane. A mathematical expression of transepidermal diffusion may be derived from Fick's Law of mass transport; factors altering the rate of diffusion are discussed. PMID:4597976

Ab initio X-ray absorption modeling of Cu-SAPO-34: Characterization of Cu exchange sites under different conditions

DOE PAGES

Zhang, Renqin; Helling, Kathy; McEwen, Jean-Sabin

2016-03-29

Copper-exchanged SAPO-34 (Cu-SAPO-34) provides excellent catalytic activity and hydrothermal sta-bility in the selective catalytic reduction (SCR) of NOxby using NH3as a reductant. Here, we find that the6-membered ring (6MR) site is the most energetically favorable for a Cu+ion while the 8-memberedring (8MR) sites are less favorable by about 0.5 eV with respect to the 6MR site in Cu-SAPO-34. Uponadsorption of molecular species (H2O, O, OH, O2), the energy differences between Cu in the 8MR and 6MRsites decreases and almost disappears. Further, a thermodynamic phase diagram study shows that a Cu+ion bound to a single H2O molecule is the most stablemore » species at low oxygen potential values while aCu2+ion bound to 2 OH species is more stable when the oxygen chemical potential is sufficiently high. Bycomparing Cu K-edge XANES between Cu-SSZ-13 and Cu-SAPO-34 with Cu in different oxidation states,we conclude that it is difficult to differentiate the simulated XANES of Cu in these structures at a givenoxidation state. By studying the Cu K-edge XANES of several favorable structures in Cu-SAPO-34 in thepresence of adspecies, the simulated XANES results capture the real trend of the edge shift with oxidationstate and gives new insights into the experimentally determined XANES of Cu-SAPO-34 obtained understandard SCR conditions.« less

Does Quality of Life Differ for Children with Autism Spectrum Disorder and Intellectual Disability Compared to Peers without Autism?

ERIC Educational Resources Information Center

Arias, Víctor B.; Gómez, Laura E.; Morán, Ma. Lucía; Alcedo, Ma. Ángeles; Monsalve, Asunción; Fontanil, Yolanda

2018-01-01

The main goal was to test if children with intellectual disability (ID) and autism spectrum disorder (ASD) show lower quality of life (QOL) in comparison to those with only ID. The KidsLife Scale was applied to 1060 children with ID, 25% of whom also had ASD, aged 4-21 years old. Those with ASD showed lower scores in several QOL domains but, when…

Differences in Autism Spectrum Disorders Incidence by Sub-Populations in Israel 1992-2009: A Total Population Study

ERIC Educational Resources Information Center

Raz, Raanan; Weisskopf, Marc G.; Davidovitch, Michael; Pinto, Ofir; Levine, Hagai

2015-01-01

We analyzed data from the Israeli National Insurance Institute (NII). Autism Spectrum Disorder (ASD) incidence was calculated for all children born in Israel 1992-2009, and by population groups. Overall, 9,109 ASD cases among 2,431,649 children were identified. ASD cumulative incidence by age 8 years increased 10-fold during 2000-2011, from 0.49 %…

1H NMR spectrum of the native human insulin monomer. Evidence for conformational differences between the monomer and aggregated forms.

PubMed

Roy, M; Lee, R W; Brange, J; Dunn, M F

1990-04-05

The effects of high dilution on the 1H Fourier transform NMR spectrum of native human insulin at pH* 8.0 and 9.3 have been examined at 500 MHz resolution. The dependence of the spectrum on concentration and comparison with the spectrum of a biologically highly potent monomeric insulin mutant (SerB9----Asp) establish that at 36 microM (pH* 9.3) or 18 microM (pH* 8) and no added buffer or salts, human insulin is monomeric. Under these conditions of dilution, ionic strength, and pH*, human insulin and the SerB9----Asp mutant exhibit nearly identical 1H NMR spectra. At higher concentrations (i.e. greater than 36 microM to 0.91 mM), native human insulin dimerizes, and this aggregation causes a change in insulin conformation. Although there are many changes in the spectrum, the TyrB26 ring H3,5 proton signals located at 6.63 ppm and the methyl signal located at 0.105 ppm (characteristics of monomeric insulin) are particularly distinct signatures of the conformation change that accompanies dimerization. Magnetization transfer experiments show that the 0.105 ppm methyl signal shifts downfield to a new position at 0.45 ppm. We conclude that the 0.105 ppm methyl signal is due to a conformation in which a Leu methyl group is centered over and in van der Waals contact with the ring of an aromatic side chain. Dimerization causes a conformation change that alters this interaction, thereby causing the downfield shift. Nuclear Overhauser studies indicate that the methyl group involved is located within a cluster of aromatic side chains and that the closest ring-methyl group interaction is with the ring of PheB24.

Soot effects on clouds and solar absorption: Understanding the differences in recently published soot mitigation experiments. (Invited)

NASA Astrophysics Data System (ADS)

Bauer, S. E.; Menon, S.

2010-12-01

Attention has been drawn to black carbon aerosols, as a target for short-term mitigation of climate warming. This measure seems attractive because soot is assumed to warm the atmosphere and at the same time has a lifetime of just a few days. Therefore regulating soot emissions could, as a short-term action, potentially buy time by slowing global warming until regulations for longer lived greenhouse gases are set in place. Currently the scientific community debates the impacts of such mitigation measures, especially when considering indirect effects. We tested with the GISS/MATRIX model, a global climate model including detailed aerosol microphysics, the effect of reducing fossil fuel emissions and bio-fuel emissions and found that opposite changes in cloud droplet number concentration lead to positive cloud forcing numbers in the bio-fuel reduction case and negative forcing numbers in the diesel mitigation case. Similar experiments have been carried out and have recently been published by other modeling groups, finding partly similar partly contradicting results to our study. In this presentation we want to explain the differences in black carbon research carried out with complex microphysical models, by focusing on the treatment of mixing state, and separation between forcings and feedbacks.

Absorption fluids data survey

NASA Astrophysics Data System (ADS)

Macriss, R. A.; Zawacki, T. S.

Development of improved data for the thermodynamic, transport and physical properties of absorption fluids were studied. A specific objective of this phase of the study is to compile, catalog and coarse screen the available US data of known absorption fluid systems and publish it as a first edition document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. The methodology and findings of the compilation, cataloguing and coarse screening of the available US data on absorption fluid properties and presents current status and future work on this project are summarized. Both in house file and literature searches were undertaken to obtain available US publications with pertinent physical, thermodynamic and transport properties data for absorption fluids. Cross checks of literature searches were also made, using available published bibliographies and literature review articles, to eliminate secondary sources for the data and include only original sources and manuscripts. The properties of these fluids relate to the liquid and/or vapor state, as encountered in normal operation of absorption equipment employing such fluids, and to the crystallization boundary of the liquid phase, where applicable. The actual data were systematically classified according to the type of fluid and property, as well as temperature, pressure and concentration ranges over which data were available. Data were sought for 14 different properties: Vapor-Liquid Equilibria, Crystallization Temperature, Corrosion Characteristics, Heat of Mixing, Liquid-Phase-Densities, Vapor-Liquid-Phase Enthalpies, Specific Heat, Stability, Viscosity, Mass Transfer Rate, Heat Transfer Rate, Thermal Conductivity, Flammability, and Toxicity.

Gold reflective metallic gratings with high absorption efficiency

NASA Astrophysics Data System (ADS)

Zhang, Zhaojian; Liang, Linmei; Yang, Junbo

2017-10-01

Electromagnetic (EM) wave absorbers are devices in which the incident radiation at the operating wavelengths can be efficiently absorbed and then transformed into ohmic heat or other forms of energy. Especially, EM absorbers based on metallic structures have distinct advantages in comparison with the traditional counterparts. Thus, they have different potential applications at different frequency ranges such as absorbing devices in solar energy harvesting systems. The reflective metallic grating is a kind of metallic EM absorbers and has the fascinating property of efficiently absorbing the incident light due to the excitation of surface plasmon polaritons (SPPs), consequently drawing more and more attention. In this paper, the absorption effect of a reflective metallic grating made of gold is studied by changing grating parameters such as the period, polarization direction of the incident light and so on. We use finite difference time-domain (FDTD) method to design the grating, and simulate the process and detect the absorption spectrum. In our design, the grating has rectangular shaped grooves and has the absorption efficiency 99% for the vertically incident transverse magnetic (TM) light at the wavelength of 818nm with the period of 800 nm, the width of 365 nm and the height of 34 nm. And then we find that the absorption spectrum is blue-shifted about 87 nm with decreasing period from 800 nm to700 nm and red-shifted about 14 nm with increasing the width of the block from 305 nm to 405 nm. The absorption becomes gradually weaker from 98% to almost zero with the polarization angle from 0° to 90°. Finally, we make a theoretical explanation to these phenomena in details. It is believed that the results may provide useful guidance for the design of EM wave absorbers with high absorption efficiency.

O2-O2 and O2-N2 collision-induced absorption mechanisms unravelled

NASA Astrophysics Data System (ADS)

Karman, Tijs; Koenis, Mark A. J.; Banerjee, Agniva; Parker, David H.; Gordon, Iouli E.; van der Avoird, Ad; van der Zande, Wim J.; Groenenboom, Gerrit C.

2018-05-01

Collision-induced absorption is the phenomenon in which interactions between colliding molecules lead to absorption of light, even for transitions that are forbidden for the isolated molecules. Collision-induced absorption contributes to the atmospheric heat balance and is important for the electronic excitations of O2 that are used for remote sensing. Here, we present a theoretical study of five vibronic transitions in O2-O2 and O2-N2, using analytical models and numerical quantum scattering calculations. We unambiguously identify the underlying absorption mechanism, which is shown to depend explicitly on the collision partner—contrary to textbook knowledge. This explains experimentally observed qualitative differences between O2-O2 and O2-N2 collisions in the overall intensity, line shape and vibrational dependence of the absorption spectrum. It is shown that these results can be used to discriminate between conflicting experimental data and even to identify unphysical results, thus impacting future experimental studies and atmospheric applications.

Retrieval of canopy water content of different crop types with two new hyperspectral indices: Water Absorption Area Index and Depth Water Index

NASA Astrophysics Data System (ADS)

Pasqualotto, Nieves; Delegido, Jesús; Van Wittenberghe, Shari; Verrelst, Jochem; Rivera, Juan Pablo; Moreno, José

2018-05-01

Crop canopy water content (CWC) is an essential indicator of the crop's physiological state. While a diverse range of vegetation indices have earlier been developed for the remote estimation of CWC, most of them are defined for specific crop types and areas, making them less universally applicable. We propose two new water content indices applicable to a wide variety of crop types, allowing to derive CWC maps at a large spatial scale. These indices were developed based on PROSAIL simulations and then optimized with an experimental dataset (SPARC03; Barrax, Spain). This dataset consists of water content and other biophysical variables for five common crop types (lucerne, corn, potato, sugar beet and onion) and corresponding top-of-canopy (TOC) reflectance spectra acquired by the hyperspectral HyMap airborne sensor. First, commonly used water content index formulations were analysed and validated for the variety of crops, overall resulting in a R2 lower than 0.6. In an attempt to move towards more generically applicable indices, the two new CWC indices exploit the principal water absorption features in the near-infrared by using multiple bands sensitive to water content. We propose the Water Absorption Area Index (WAAI) as the difference between the area under the null water content of TOC reflectance (reference line) simulated with PROSAIL and the area under measured TOC reflectance between 911 and 1271 nm. We also propose the Depth Water Index (DWI), a simplified four-band index based on the spectral depths produced by the water absorption at 970 and 1200 nm and two reference bands. Both the WAAI and DWI outperform established indices in predicting CWC when applied to heterogeneous croplands, with a R2 of 0.8 and 0.7, respectively, using an exponential fit. However, these indices did not perform well for species with a low fractional vegetation cover (<30%). HyMap CWC maps calculated with both indices are shown for the Barrax region. The results confirmed the

Variation in mutation spectrum partly explains regional differences in the breast cancer risk of female BRCA mutation carriers in the Netherlands.

PubMed

Vos, Janet R; Teixeira, Natalia; van der Kolk, Dorina M; Mourits, Marian J E; Rookus, Matti A; van Leeuwen, Flora E; Collée, Margriet; van Asperen, Christi J; Mensenkamp, Arjen R; Ausems, Margreet G E M; van Os, Theo A M; Meijers-Heijboer, Hanne E J; Gómez-Garcia, Encarna B; Vasen, Hans F; Brohet, Richard M; van der Hout, Annemarie H; Jansen, Liesbeth; Oosterwijk, Jan C; de Bock, Geertruida H

2014-11-01

We aimed to quantify previously observed relatively high cancer risks in BRCA2 mutation carriers (BRCA2 carriers) older than 60 in the Northern Netherlands, and to analyze whether these could be explained by mutation spectrum or population background risk. This consecutive cohort study included all known pathogenic BRCA1/2 carriers in the Northern Netherlands (N = 1,050). Carrier and general reference populations were: BRCA1/2 carriers in the rest of the Netherlands (N = 2,013) and the general population in both regions. Regional differences were assessed with HRs and ORs. HRs were adjusted for birth year and mutation spectrum. All BRCA1 carriers and BRCA2 carriers younger than 60 had a significantly lower breast cancer risk in the Northern Netherlands; HRs were 0.66 and 0.64, respectively. Above age 60, the breast cancer risk in BRCA2 carriers in the Northern Netherlands was higher than in the rest of the Netherlands [HR, 3.99; 95% confidence interval (CI), 1.11-14.35]. Adjustment for mutational spectrum changed the HRs for BRCA1, BRCA2 <60, and BRCA2 ≥60 years by -3%, +32%, and +11% to 0.75, 0.50, and 2.61, respectively. There was no difference in background breast cancer incidence between the two regions (OR, 1.03; 95% CI, 0.97-1.09). Differences in mutation spectrum only partly explain the regional differences in breast cancer risk in BRCA2 carriers, and for an even smaller part in BRCA1 carriers. The increased risk in BRCA2 carriers older than 60 may warrant extension of intensive breast screening beyond age 60. ©2014 American Association for Cancer Research.

Photobleaching response of different sources of chromophoric dissolved organic matter exposed to natural solar radiation using absorption and excitation-emission matrix spectra.