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Sample records for uv photoabsorption spectrum

  1. Theoretical study of the near uv photoabsorption by the Kr2* excimer

    International Nuclear Information System (INIS)

    Harvey, J.F.

    1990-04-01

    The physical process responsible for near UV photoabsorption by the Kr* 2 excimer are examined and the energy dependence of the photoabsorption cross sections is calculated. Near UV photoabsorption by the Kr* 2 is a multiprocess phenomenon involving direct photoionization and concurrent photoexcitation to a repulsive resonance state, which subsequently autoionizes or dissociates. An adiabatic nuclei theory is developed, based on the use of Feshbach projection operators, to separate the ionization and dissociation channels, and to device photoionization and photodissociation cross sections. These cross sections are expressed in terms of parameters obtained from fixed nuclei electronic calculations and in terms wavefunctions describing nuclear motion. Stieltjes Tchebycheff Moment Theory (STMT) techniques are used to extract information concerning the ionization continuum from localized L 2 electronic wavefunctions obtained from molecular electronic structure codes. Problems in the application of STMT techniques to narrow spectral features are examined. The cause of these problems is determined to be the use of the histogram midpoint approximation in low order STMT quadratures. Techniques are then developed which significantly improve the accuracy of STMT calculations for an isolated, narrow, resonance in a single continuum. Improved treatment of resonance profiles is demonstrated for pure Fano profiles, a shape resonance in a model barrier-and-well potential, and a shape resonance in the K-shell photoionization spectrum of N 2 . The improved STMT techniques are then used to obtain the fixed nuclei resonance profiles in the spectrum of Kr 2

  2. UV photoabsorption cross sections of CO, N2, and SO2 for studies of the ISM and planetary atmospheres

    Science.gov (United States)

    Smith, Peter L.; Rufus, J.; Yoshino, K.; Parkinson, W. H.; Stark, Glenn; Pickering, Juliet C.; Thorne, A. P.

    2002-01-01

    We report high-resolution laboratory measurements of photoabsorption cross sections of CO, N2, and SO2 in the wavelength range 80 to 320 nm. The motivation is to provide the quantitative data that are needed to analyze observations of absorption by, and to model photochemical processes in, the interstellar medium and a number of planetary atmospheres. Because of the high resolution of the spectrometers used, we can minimize distortion of the spectrum that occurs when instrument widths are greater than the widths of spectral features being measured. In many cases, we can determine oscillator strengths of individual rotational lines - a unique feature of our work.

  3. The X-ray photoabsorption spectrum of potassium near the K-edge

    International Nuclear Information System (INIS)

    Azuma, Y.; Berry, H.G.; Cowan, P.L.; Gemmell, D.S.; LeBrun, T.

    1996-01-01

    The authors have used a heat-pipe target in an X-ray beam to obtain photoabsorption spectra of potassium at the K- and KM-edges, in the photon energy range 3,600 to 3,650 eV. Preliminary identifications of most of the peaks observed are made using Dirac Hartree-Fock calculations. They compare these results with those obtained previously in closed-shell rare gas absorption spectra

  4. The 4p-subshell photoabsorption spectrum of singly ionized molybdenum

    International Nuclear Information System (INIS)

    Mansfield, M W D; Costello, J T; Kennedy, E T; Mosnier, J-P

    2003-01-01

    The 4p-subshell spectrum of Mo + has been recorded, for the first time, in the wavelength range 500-200 A. The spectrum is dominated by a 4p → 4d 'giant resonance' on which extensive discrete structure is superposed. With only one exception the discrete lines can be ordered into six Rydberg series, 4p 6 4d 56 S 5/2 → 4p 5 (4d 56 S)( 7 P)ns,nd (J = 3/2, 5/2, 7/2), converging on three limits, the Mo III levels 4p 5 (4d 56 S) 7 P 4,3,2 . The observed spectrum is analysed by comparison with both Hartree plus exchange with relativistic corrections and relativistic time-dependent local density approximation calculations. The evolution of the discrete structure line shapes interacting with the giant resonance is found to be in qualitative agreement with the theory of Connerade and Lane (1987 J. Phys. B: At. Mol. Phys. 20 L181-6)

  5. The precipitation synthesis of broad-spectrum UV absorber nanoceria

    International Nuclear Information System (INIS)

    Nurhasanah, Iis; Sutanto, Heri; Puspaningrum, Nurul Wahyu

    2013-01-01

    In this paper the possibility of nanoceria as broad-spectrum UV absorber was evaluated. Nanoceria were synthesized by precipitation process from cerium nitrate solution and ammonium hydroxide as precipitant agent. Isopropanol was mixed with water as solvent to prevent hard agglomeration. The structure of resulting nanoceria was characterized by x-ray diffractometer (XRD). The transparency in the visible light and efficiency of protection in UV A region were studied using ultraviolet-visible (UV - Vis) spectrophotometer. The results show that nanoceria possess good tranparency in visible light and high UV light absorption. The critical absorption wavelenght of 368 nm was obtained which is desirable for excellent broad-spectrum protection absorbers. Moreover, analysis of photodegradation nanoceria to methylene blue solution shows poor photocatalytic activity. It indicates that nanoceria suitable for used as UV absorber in personal care products

  6. Photoabsorption and photodissociation studies of dimethyl sulphoxide (DMSO) in the 35,000-80,000 cm-1 region using synchrotron radiation

    Science.gov (United States)

    Mandal, Anuvab; Singh, Param Jeet; Shastri, Aparna; Sunanda, K.; Jagatap, B. N.

    2015-05-01

    Photoabsorption and photodissociation studies of dimethyl sulphoxide and its deuterated isotopologue (DMSO-h6 and DMSO-d6) are performed using synchrotron radiation in the 35,000-80,000 cm-1 region. In the photoabsorption spectrum, Rydberg series converging to the first three ionization potentials of DMSO at 9.1, 10.1 and 12.3 eV corresponding to removal of an electron from the highest three occupied molecular orbitals (14a‧, 7a″ and 13a‧) are observed. Based on a quantum defect analysis, Rydberg series assignments are extended to higher members as compared to earlier works and a few ambiguities in earlier assignments are clarified. Analysis is aided by quantum chemical calculations using the DFT and TDDFT methodologies. Vibronic structures observed in the spectrum of DMSO-h6 in the regions 7.7-8.1 eV and 8.1-8.8 eV are attributed to the transitions 7a″→4p at 7.862 eV and 14a‧→6s/4d at 8.182 eV, respectively. Photoabsorption spectra of DMSO-h6 and -d6 recorded using a broad band incident radiation show prominent peaks, which are identified and assigned to electronic and vibronic transitions of the SO radical. This provides a direct confirmation of the fact that DMSO preferentially dissociates into CH3 and SO upon UV-VUV excitation, as proposed in earlier photodissociation studies. An extended vibronic band system associated with the e1Π-X3Σ- transition of the SO radical is identified and assigned. The complete VUV photoabsorption spectrum of DMSO-d6 is also reported here for the first time.

  7. Fine structure of the CCl3 UV absorption spectrum and CCl3 kinetics

    DEFF Research Database (Denmark)

    Ellermann, T.

    1992-01-01

    The UV gas-phase spectrum of CCl3 was recorded in the range 220-300 nm using pulse radiolysis of CHCl3/SF6 or CCl4/Ar gas mixtures. The UV spectrum exhibits a pronounced vibrational fine structure which is assigned to transition into the (C2A1'(3s)) Rydberg state. The vibronic progression has...

  8. The electronic states of 1,2,3-triazole studied by vacuum ultraviolet photoabsorption and ultraviolet photoelectron spectroscopy, and a comparison with ab initio configuration interaction methods

    DEFF Research Database (Denmark)

    Palmer, Michael H.; Hoffmann, Søren Vrønning; Jones, Nykola C.

    2011-01-01

    The Rydberg states in the vacuum ultraviolet photoabsorption spectrum of 1,2,3-triazole have been measured and analyzed with the aid of comparison to the UV valence photoelectron ionizations and the results of ab initio configuration interaction (CI) calculations. Calculated electronic ionization...... and excitation energies for singlet, triplet valence, and Rydberg states were obtained using multireference multiroot CI procedures with an aug-cc-pVTZ [5s3p3d1f] basis set and a set of Rydberg [4s3p3d3f] functions. Adiabatic excitation energies obtained for several electronic states using coupled...... are the excitations consistent with an f-series....

  9. A P25/(NH4)xWO3 hybrid photocatalyst with broad spectrum photocatalytic properties under UV, visible, and near-infrared irradiation.

    Science.gov (United States)

    Yang, Linfen; Liu, Bin; Liu, Tongyao; Ma, Xinlong; Li, Hao; Yin, Shu; Sato, Tsugio; Wang, Yuhua

    2017-04-03

    In this study, a series of hybrid nanostructured photocatalysts P25/(NH 4 ) x WO 3 nanocomposites with the average crystallite size of P25 and (NH 4 ) x WO 3 of the sample was calculated to be about 30 nm and 130 nm, were successfully synthesized via a simple one-step hydrothermal method. The as-obtained samples was characterized by transmission electron microscopy (TEM), which implies that the P25/(NH 4 ) x WO 3 nanocomposites are fabricated with favourable nanosizd interfacial. The XPS results confirmed that the obtained sample consists of mixed chemical valences of W 5+ and W 6+ , the low-valance W 5+ sites could be the origin of NIR absorption. As revealed by optical absorption results, P25/(NH 4 ) x WO 3 nanocomposites possess high optical absorption in the whole solar spectrum of 200-2500 nm. Benefiting from this unique photo-absorption property and the synergistic effect of P25 and (NH 4 ) x WO 3 , broad spectrum response photocatalytic activities covering UV, visible and near infrared regions on degradation of Rhodamine B have been realized by P25/(NH 4 ) x WO 3 nanocomposites. Meanwhile, the stability of photocatalysts was examined by the XRD and XPS of the photocatalysts after the reaction. The results show that P25/(NH 4 ) x WO 3 photocatalysts has a brilliant application prospect in the energy utilization to solve deteriorating environmental issues.

  10. Photoabsorption of atomic hydrogen in an external DC electric field

    International Nuclear Information System (INIS)

    Gailitis, Modris; Gailitis, Agris

    1996-01-01

    An analytical approach is presented which aids the computation of the photoabsorption spectrum of atomic hydrogen in a weak external DC electric field. Separation constants in the parabolic frame and one of the normalization factors are evaluated by the Telnov algorithm. For matrix elements the series expansion after powers of parabolic coordinates is used. An enhanced precision arithmetic is applied to extract the second normalization factor from the power expansion. The results agree with those from the previous calculations and experiment. (Author)

  11. Hγ Line Spectrum of Intermediate Polars

    Directory of Open Access Journals (Sweden)

    Yonggi Kim

    1998-06-01

    Full Text Available Kim & Beuermann (1995, 1996 have developed a model for the propagation of X-rays from the accreting white dwarf through the infalling material and the re-emission of the energy deposited by photo-absorption in the optical (and UV spectral range. By using this model, we calculate the profiles of the Hγ emission-line spectrum of intermediate polars. Photoabsorption of X-rays by the infalling material is the dominant process in forming the observed energy-dependent rotational modulation of the X-ray flux. X-ray and optical modulations are sensitive to model parameters in different ways. In principle, these dependencies allow us to obtain improved insight into the accretion geometry of the intermediate polars. We present results of our calculations and compare them with the Hβ line spectrum (Kim & Beuermann 1996.

  12. Rydberg states of chloroform studied by VUV photoabsorption spectroscopy

    Science.gov (United States)

    Singh, Param Jeet; Shastri, Aparna; D'Souza, R.; Jagatap, B. N.

    2013-11-01

    The VUV photoabsorption spectra of CHCl3 and CDCl3 in the energy region 6.2-11.8 eV (50,000-95,000 cm-1) have been investigated using synchrotron radiation from the Indus-1 source. Rydberg series converging to the first four ionization limits at 11.48, 11.91, 12.01 and 12.85 eV corresponding to excitation from the 1a2, 4a1, 4e, 3e, orbitals of CHCl3 respectively are identified and analyzed. Quantum defect values are observed to be consistent with excitation from the chlorine lone pair orbitals. Vibrational progressions observed in the region of 72,500-76,500 cm-1 have been reassigned to ν3 and combination modes of ν3+ν6 belonging to the 1a2→4p transition in contrast to earlier studies where they were assigned to a ν3 progression superimposed on the 3e→4p Rydberg transition. The assignments are further confirmed based on isotopic substitution studies on CDCl3 whose VUV photoabsorption spectrum is reported here for the first time. The frequencies of the ν3 and ν6 modes in the 4p Rydberg state of CHCl3 (CDCl3) are proposed to be ~454 (409) cm-1 and~130 (129) cm-1 respectively based on the vibronic analysis. DFT calculations of neutral and ionic ground state vibrational frequencies support the vibronic analysis. Experimental spectrum is found to be in good agreement with that predicted by TDDFT calculations. This work presents a consolidated analysis of the VUV photoabsorption spectrum of chloroform.

  13. Rydberg states of chloroform studied by VUV photoabsorption spectroscopy

    International Nuclear Information System (INIS)

    Singh, Param Jeet; Shastri, Aparna; D’Souza, R.; Jagatap, B.N.

    2013-01-01

    The VUV photoabsorption spectra of CHCl 3 and CDCl 3 in the energy region 6.2–11.8 eV (50,000–95,000 cm −1 ) have been investigated using synchrotron radiation from the Indus-1 source. Rydberg series converging to the first four ionization limits at 11.48, 11.91, 12.01 and 12.85 eV corresponding to excitation from the 1a 2 , 4a 1 , 4e, 3e, orbitals of CHCl 3 respectively are identified and analyzed. Quantum defect values are observed to be consistent with excitation from the chlorine lone pair orbitals. Vibrational progressions observed in the region of 72,500–76,500 cm −1 have been reassigned to ν 3 and combination modes of ν 3 +ν 6 belonging to the 1a 2 →4p transition in contrast to earlier studies where they were assigned to a ν 3 progression superimposed on the 3e→4p Rydberg transition. The assignments are further confirmed based on isotopic substitution studies on CDCl 3 whose VUV photoabsorption spectrum is reported here for the first time. The frequencies of the ν 3 and ν 6 modes in the 4p Rydberg state of CHCl 3 (CDCl 3 ) are proposed to be ∼454 (409) cm −1 and∼130 (129) cm −1 respectively based on the vibronic analysis. DFT calculations of neutral and ionic ground state vibrational frequencies support the vibronic analysis. Experimental spectrum is found to be in good agreement with that predicted by TDDFT calculations. This work presents a consolidated analysis of the VUV photoabsorption spectrum of chloroform. -- Highlights: •VUV photoabsorption spectra of CHCl 3 and CDCl 3 studied using synchrotron radiation. •Quantum defect analysis of Rydberg series converging to first four ionization limits. •Vibronic bands in 72,500–76,500 cm −1 region assigned to 1a 2 →4p Rydberg transition. •Vibrational progressions assigned to ν 3 and ν 3 +ν 6 using ab initio calculations. •Excellent agreement of TDDFT vertical excited energies with experimental spectrum

  14. [Investigation of multi-wavelength effect during the measurement of UV-enhanced film's emission spectrum].

    Science.gov (United States)

    Liu, Meng; Ni, Zheng-ji; Zhang, Da-wei; Huang, Yuan-shen; Zhuang, Song-lin

    2009-09-01

    The UV-responsive detector is a dual-use device for civilian and military after the laser and IR-responsive sensors. Typical image sensor coated with a layer of down-convert frequency thin film on it's photosurface to enhance UV response is the key technology of enhancing UV-response. The UV-enhanced thin film was made in the experimental laboratory using the Zn2SiO4:Mn phosphor by spin coating method. Two peaks at 520 and 560 nm respectively in the emission spectrum of the UV-enhanced film were found by SP1702 spectrograph when the excitation wavelength was 260 and 280 nm. The peaks were found in the process of experiment of measuring and counting the quantum efficiency of UV-enhanced thin film. But the light peaks at 520 and 560 nm are not the emission light peaks by the exciting light of 260 and 280 nm. The reason why the light at 520 and 560 nm is not the emission light was analyzed based on the measurement principle of grating spectrograph. The reasons for the multi-wavelength of light overlaps during the measurement of emission spectrum were also discussed. And the equipment used to separate the overlapped different wavelengths was designed, which will be used to resolve the problem of the overlap of multi-wavelength.

  15. Photocatalytic ROS production and phototoxicity of titanium dioxide nanoparticles is dependent on solar UV radiation spectrum

    Science.gov (United States)

    Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO2) and its consequent phototoxicity to Daphnia magna were measured under different solar UV radiation spectrum by applying a series of optical filters in a solar simulator. Removing UVB (280-32...

  16. The UV (IUE) spectrum of the planetary nebula PC 11 (HD 149427)

    NARCIS (Netherlands)

    Parthasarathy, M; Garcia-Lario, P; Pottasch, [No Value; de Martino, D; Surendiranath, R

    The UV spectrum of PC 11 is found to show variations in the strength of the O III] 1666 Angstrom, N III] 1750 Angstrom and C III] 1909 Angstrom emission lines. The detection of continuum emission in the wavelength interval 2650 Angstrom to 3200 Angstrom indicates that the central star of PC 11 has

  17. On the Soft Limit of the Large Scale Structure Power Spectrum: UV Dependence

    CERN Document Server

    Garny, Mathias; Porto, Rafael A; Sagunski, Laura

    2015-01-01

    We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the soft limit. The resulting equation encodes the coupling to ultraviolet (UV) modes in two time-dependent coefficients, which may be obtained from response functions to (anisotropic) parameters, such as spatial curvature, in a modified cosmology. We argue that both depend weakly on fluctuations deep in the UV. As a byproduct, this implies that the renormalized leading order coefficient(s) in the effective field theory (EFT) of large scale structures receive most of their contribution from modes close to the non-linear scale. Consequently, the UV dependence found in explicit computations within standard perturbation theory stems mostly from counter-term(s). We confront a simplified version of our non-perturbative equation against existent numerical simulations, and find good agr...

  18. Formation of the UV Spectrum of Molecular Hydrogen in the Sun

    Science.gov (United States)

    Jaeggli, S. A.; Judge, P. G.; Daw, A. N.

    2018-03-01

    Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the τ = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550 Å is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.

  19. Photoabsorption of small sodium and magnesium clusters

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2004-01-01

    We predict the strong enhancement in the photoabsorption of small Mg clusters in the region of 4-5 eV due to the resonant excitation of the plasmon oscillations of cluster electrons. The photoabsorption spectra for neutral Mg clusters consisting of up to N=11 atoms have been calculated using it ab...... initio framework based on the time dependent density functional theory (TDDFT). The nature of predicted resonances has been elucidated by comparison of the results of the it ab initio calculations with the results of the classical Mie theory. The splitting of the plasmon resonances caused by the cluster...

  20. A laboratory experimental setup for photo-absorption studies using synchrotron radiation

    CERN Document Server

    Shastri, A; Saraswati, P; Sunanda, K

    2002-01-01

    The photophysics beamline, which is being installed at the 450 MeV Synchrotron Radiation Source (SRS), Indus-l, is a medium resolution beamline useful for a variety of experiments in the VUV region viz. 500-2000 A. One of the major applications of this beamline is gas-phase photo-absorption studies. An experimental set up to be used for these experiments was designed, developed and tested in our laboratory. The setup consists of a high vacuum absorption cell, 1/4 m monochromator and detection system. For the purpose of testing, xenon and tungsten continuum sources were used and absorption spectra were recorded in the UV region. This setup was used to record the absorption spectrum of a few molecules like acetone, ammonia, benzene, formaldehyde and acetaldehyde in order to evaluate the performance of the experimental system which will subsequently be used with the photophysics beamline. Details of the design, fabrication and testing of the absorption cell and experimental procedures are presented in this repor...

  1. The far-UV spectrum of the low-excitation planetary nebula HD 138403

    OpenAIRE

    Surdej, Jean; Heck, A.

    1982-01-01

    Two high-resolution far-UV spectra of the low-excitation planetary nebula HD 138403 are analyzed which were obtained with the IUE satellite over the wavelength range from 1170 to 2070 A. It is shown that the nebula's far-UV spectrum comprises a stellar continuum on which are superimposed a few emission lines, numerous interstellar absorption lines, and various types of P Cygni profiles. Evidence is examined for substantial mass loss from the central nucleus, with terminal velocities of the or...

  2. An action spectrum for UV-B radiation and the rat lens.

    Science.gov (United States)

    Merriam, J C; Löfgren, S; Michael, R; Söderberg, P; Dillon, J; Zheng, L; Ayala, M

    2000-08-01

    To determine an action spectrum for UV-B radiation and the rat lens and to show the effect of the atmosphere and the cornea on the action spectrum. One eye of young female rats was exposed to 5-nm bandwidths of UV-B radiation (290, 295, 300, 305, 310, and 315 nm). Light scattering of exposed and nonexposed lenses was measured 1 week after irradiation. A quadratic polynomial was fit to the dose-response curve for each wave band. The dose at each wave band that produced a level of light scattering greater than 95% of the nonexposed lenses was defined as the maximum acceptable dose (MAD). Transmittance of the rat cornea was measured with a fiberoptic spectrophotometer. The times to be exposed to the MAD in Stockholm (59.3 degrees N) and La Palma (28 degrees N) were compared. Significant light scattering was detected after UV-B at 295, 300, 305, 310, and 315 nm. The lens was most sensitive to UV-B at 300 nm. Correcting for corneal transmittance showed that the rat lens is at least as sensitive to UV radiation at 295 nm as at 300 nm. The times to be exposed to the MAD at each wave band were greater in Stockholm than in La Palma, and in both locations the theoretical time to be exposed to the MAD was least at 305 nm. After correcting for corneal transmittance, the biological sensitivity of the rat lens to UV-B is at least as great at 295 nm as at 300 nm. After correcting for transmittance by the atmosphere, UV-B at 305 nm is the most likely wave band to injure the rat lens in both Stockholm and La Palma.

  3. Evolution of the near-UV emission spectrum associated with the reduction process in microwave iron making.

    Science.gov (United States)

    Matsubara, Akihiro; Takayama, Sadatsugu; Okajima, Shigeki; Sato, Motoyasu

    2008-01-01

    The structure of the emission spectrum in the near-UV range (240 nm-310 nm) changes drastically from the continuous spectrum to a discrete line spectrum with increasing sample temperature during the carbothermic reduction of magnetite in a 2.45 GHz microwave multimode furnace. The continuous spectrum can be assigned as a cathodoluminescence of magnetite. The dynamic evolution of the spectrum from continuous to discrete represents the progress of the reduction from magnetite to iron.

  4. A study of the valence shell photoelectron and photoabsorption spectra of CF3SF5

    International Nuclear Information System (INIS)

    Holland, D M P; Shaw, D A; Walker, I C; McEwen, I J; Apra, E; Guest, M F

    2005-01-01

    The outer valence shell photoelectron spectrum of CF 3 SF 5 has been studied experimentally and theoretically. Synchrotron radiation has been used to record angle-resolved outer valence shell photoelectron spectra of CF 3 SF 5 in the photon energy range 18-60 eV. These spectra have allowed photoelectron asymmetry parameters and branching ratios to be derived. The Outer Valence Green's Function approach has been employed to calculate the molecular orbital configuration and associated binding energies. A charge distribution analysis has also been obtained. Assignments have been proposed for the peaks observed in the photoelectron spectrum. The absolute photoabsorption cross section of CF 3 SF 5 has been measured from threshold to 40 eV, and strongly resembles that of SF 6 . Assignments, involving intravalence transitions, have been proposed for some of the principal features appearing in the photoabsorption spectrum of CF 3 SF 5

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  7. UV-visible spectrum of the phenyl radical and kinetics of its reaction with NO in the gas phase

    DEFF Research Database (Denmark)

    Wallington, T.J.; Egsgaard, H.; Nielsen, O.J.

    1998-01-01

    Pulse radiolysis transient UV-visible absorption spectroscopy was used to study the UV-visible absorption spectrum (225-575 nm) of the phenyl radical, C6H5(.), and kinetics of its reaction with NO. Phenyl radicals have a strong broad featureless absorption in the region of 225-340 nm...

  8. On the soft limit of the large scale structure power spectrum. UV dependence

    International Nuclear Information System (INIS)

    Garny, Mathias

    2015-08-01

    We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the soft limit. The resulting equation encodes the coupling to ultraviolet (UV) modes in two time-dependent coefficients, which may be obtained from response functions to (anisotropic) parameters, such as spatial curvature, in a modified cosmology. We argue that both depend weakly on fluctuations deep in the UV. As a byproduct, this implies that the renormalized leading order coefficient(s) in the effective field theory (EFT) of large scale structures receive most of their contribution from modes close to the non-linear scale. Consequently, the UV dependence found in explicit computations within standard perturbation theory stems mostly from counter-term(s). We confront a simplified version of our non-perturbative equation against existent numerical simulations, and find good agreement within the expected uncertainties. Our approach can in principle be used to precisely infer the relevance of the leading order EFT coefficient(s) using small volume simulations in an 'anisotropic separate universe' framework. Our results suggest that the importance of these coefficient(s) is a ∝ 10% effect, and plausibly smaller.

  9. Photoabsorption in sodium clusters: first principles configuration interaction calculations

    Science.gov (United States)

    Priya, Pradip Kumar; Rai, Deepak Kumar; Shukla, Alok

    2017-05-01

    We present systematic and comprehensive correlated-electron calculations of the linear photoabsorption spectra of small neutral closed- and open-shell sodium clusters (Nan, n = 2 - 6), as well as closed-shell cation clusters (Nan+, n = 3, 5). We have employed the configuration interaction (CI) methodology at the full CI (FCI) and quadruple CI (QCI) levels to compute the ground, and the low-lying excited states of the clusters. For most clusters, besides the minimum energy structures, we also consider their energetically close isomers. The photoabsorption spectra were computed under the electric-dipole approximation, employing the dipole-matrix elements connecting the ground state with the excited states of each isomer. Our calculations were tested rigorously for convergence with respect to the basis set, as well as with respect to the size of the active orbital space employed in the CI calculations. These calculations reveal that as far as electron-correlation effects are concerned, core excitations play an important role in determining the optimized ground state geometries of various clusters, thereby requiring all-electron correlated calculations. But, when it comes to low-lying optical excitations, only valence electron correlation effects play an important role, and excellent agreement with the experimental results is obtained within the frozen-core approximation. For the case of Na6, the largest cluster studied in this work, we also discuss the possibility of occurrence of plasmonic resonance in the optical absorption spectrum. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-70728-3

  10. [Determination of Bloodstain Age by UV Visible Integrating Sphere Reflection Spectrum].

    Science.gov (United States)

    Yan, L Q; Gao, Y

    2016-10-01

    To establish a method for rapid identification of bloodstain age. Under laboratory conditions (20 ℃, 25 ℃ and 30 ℃), an integrating sphere ISR-240A was used as a reflection accessory on an UV-2450 UV-vis spectrophotometer, and a standard white board of BaSO₄ was used as reference, the reflection spectrums of bloodstain from human ears' venous blood were measured at regular intervals. The reflection radios R ₅₄₁ and R ₅₇₇ at a specific wavelength were collected and the value of R ₅₄₁/ R ₅₇₇ was calculated. The linear fitting and regression analysis were done by SPSS 17.0. The results of regression analysis showed that R ² of the ratios of bloodstain age to UV visible reflectivity in specific wavelengths were larger than 0.8 within 8 hours and under certain circumstances. The regression equation was established. The bloodstain age had significant correlation with the value of R ₅₄₁/ R ₅₇₇. The method of inspection is simple, rapid and nondestructive with a good reliability, and can be used to identify the bloodstain age within 8 hours elapsed-time standards under laboratory conditions. Copyright© by the Editorial Department of Journal of Forensic Medicine

  11. High-resolution Fourier-transform extreme ultraviolet photoabsorption spectroscopy of 14N15N

    Science.gov (United States)

    Heays, A. N.; Dickenson, G. D.; Salumbides, E. J.; de Oliveira, N.; Joyeux, D.; Nahon, L.; Lewis, B. R.; Ubachs, W.

    2011-12-01

    The first comprehensive high-resolution photoabsorption spectrum of 14N15N has been recorded using the Fourier-transform spectrometer attached to the Desirs beamline at the Soleil synchrotron. Observations are made in the extreme ultraviolet and span 100 000-109 000 cm-1 (100-91.7 nm). The observed absorption lines have been assigned to 25 bands and reduced to a set of transition energies, f values, and linewidths. This analysis has verified the predictions of a theoretical model of N2 that simulates its photoabsorption and photodissociation cross section by solution of an isotopomer independent formulation of the coupled-channel Schrödinger equation. The mass dependence of predissociation linewidths and oscillator strengths is clearly evident and many local perturbations of transition energies, strengths, and widths within individual rotational series have been observed.

  12. CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

    Science.gov (United States)

    Wu, Jie; Liu, Baibai; Ren, Zhenxing; Ni, Mengying; Li, Can; Gong, Yinyan; Qin, Wei; Huang, Yongli; Sun, Chang Q; Liu, Xinjuan

    2018-05-01

    To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions. As co-catalyst, RGO can separate and inhibit the recombination of charge carriers, consequently improving the catalytic activity. Only 1wt% RGO emersions can reduce 90% of Cr(VI) under the radiation of light over the full spectrum. Findings may provide a new strategy and substance to expand the utilization range of solar light from UV to visible even the NIR energy. Copyright © 2017. Published by Elsevier Inc.

  13. Photoabsorption by the 3d shell in Ce, Pr, Ho, and Er: Observations and calculations

    International Nuclear Information System (INIS)

    Sugar, J.; Brewer, W.D.; Kalkowski, G.; Kaindl, G.; Paparazzo, E.

    1985-01-01

    Improved 3d photoabsorption spectra of the series of rare-earth fluorides have been obtained by recording total electron yield and using monochromatized synchrotron radiation. They are compared with predicted spectra resulting from an average-of-configuration calculation of wave functions employing radial integrals adjusted to the observed spectrum in each case; results are presented here for Ce, Pr, Ho, and Er spectra. Improved resolution of the Ce spectrum permitted for the first time a determination of the proper scaling for all of the electrostatic parameters

  14. An action spectrum for UV-induced attachment of V79 Chinese hamster cells to a substratum

    Energy Technology Data Exchange (ETDEWEB)

    Baanrud, H; Berg, K; Platou, T; Moan, J [Inst. for Cancer Research, Oslo (Norway). Dept. of Biophysics

    1993-10-01

    When cells growing in monolayers are exposed to ultraviolet radiation (UV), their binding to the substratum is increased in strength. An action spectrum for such UV-induced binding was determined, using the time needed for trypsin-EDTA to detach the cells as a measure of binding strength. This action spectrum was significantly different from that for cell inactivation, also determined. At the shortest wavelengths (297/302, 313 nm) lethal fluences were needed to induce measurable binding while at the longest wavelengths (365, 405 nm) completely nonlethal fluences induced strong and persistent binding. (author).

  15. The UV spectrum of the BL Lac object PKS 0521-36

    International Nuclear Information System (INIS)

    Danziger, I.J.; Bergeron, J.; Maraschi, L.; Treves, A.; Milan Univ.; Tanzi, E.G.

    1983-01-01

    Ultraviolet observations (1200 to 3000 A) with the IUE satellite of the BL Lac object PKS 0521-36 are presented. The only emission line which appears clearly in the spectrum is Lyα, which is asymmetric with a component displaced approx. 3000 km s - 1 to the red. The intensity of the line and the upper limits on other lines are compared with the model calculations on QSOs and Seyfert nuclei by Kwan and Krolik. The continuous energy distribution is discussed, combining non-simultaneous observations from the ultraviolet to the infrared. The spectral range of the non-thermal source from far IR to far UV can be described by a single power law of index -1.5. (author)

  16. UV spectrum of the BL Lac object PKS 0521-36

    Energy Technology Data Exchange (ETDEWEB)

    Danziger, I.J. (European Southern Observatory, Garching (Germany, F.R.)); Bergeron, J. (Centre National de la Recherche Scientifique, 75 - Paris (France). Inst. d' Astrophysique); Fosbury, R.A.E. (Royal Greenwich Observatory, Hailsham (UK)); Maraschi, L.; Treves, A. (Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica Cosmica; Milan Univ. (Italy). Ist. di Fisica); Tanzi, E.G. (Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica Cosmica)

    1983-05-01

    Ultraviolet observations (1200 to 3000 A) with the IUE satellite of the BL Lac object PKS 0521-36 are presented. The only emission line which appears clearly in the spectrum is Ly..cap alpha.., which is asymmetric with a component displaced approx. 3000 km s/sup -1/ to the red. The intensity of the line and the upper limits on other lines are compared with the model calculations on QSOs and Seyfert nuclei by Kwan and Krolik. The continuous energy distribution is discussed, combining non-simultaneous observations from the ultraviolet to the infrared. The spectral range of the non-thermal source from far IR to far UV can be described by a single power law of index -1.5.

  17. X-Ray Photoabsorption in Magnesium Ions

    Science.gov (United States)

    Abdel-Naby, Sh. A.; Hasoglu, M. F.; Nicolić, D.; Gorczyca, T. W.

    2009-05-01

    K-shell photoabsorption cross sections are necessary for determining elemental abundances of the interstellar medium (ISM) from observed X-ray spectra. Over the past few years, our group has computed reliable K-shell photoabsorption calculations for oxygen [1-3], neon [4,5], and carbon [6] ions. We extend our calculations to magnesium ions using a state-of-the-art R-matrix method that incorporates the important Auger broadening and pseudoresonanace-elimination effects. Comparisons with available independent-particle (IP) results and other available data will also be presented. This work was supported in part by NASA's Astronomy Physics Research and Analysis (APRA) and Solar and Heliospheric Physics (SHP) Supporting Research and Technology (SR&T) programs. [1] T. W. Gorczyca and B. M. McLaughlin. J Phys. B. 33, L859 (2000). [2] A. M. Juett, et al., Astrophys. J. 612, 308 (2004). [3] J. Garcia et al, Astrophys. J. Supp. S. 158, 68 (2005). [4] T. W. Gorczyca., Phys. Rev. A. 61, 024702 (2000). [5] A. M. Juett, et al, Astrophys. J. 648, 1066 (2006). [6] M. F. Hasoglu, et al, Astrophys. J., (in preparation)

  18. The UV Spectrum of the Ultracool Dwarf LSR J1835+3259 Observed with the Hubble Space Telescope

    Science.gov (United States)

    Saur, Joachim; Fischer, Christian; Wennmacher, Alexandre; Feldman, Paul D.; Roth, Lorenz; Strobel, Darrell F.; Reiners, Ansgar

    2018-05-01

    An interesting question about ultracool dwarfs recently raised in the literature is whether their emission is purely internally driven or partially powered by external processes similar to planetary aurora known from the solar system. In this work, we present Hubble Space Telescope observations of the energy fluxes of the M8.5 ultracool dwarf LSR J1835+3259 throughout the ultraviolet (UV). The obtained spectra reveal that the object is generally UV-fainter compared with other earlier-type dwarfs. We detect the Mg II doublet at 2800 Å and constrain an average flux throughout the near-UV. In the far-UV without Lyα, the ultracool dwarf is extremely faint with an energy output at least a factor of 250 smaller as expected from auroral emission physically similar to that on Jupiter. We also detect the red wing of the Lyα emission. Our overall finding is that the observed UV spectrum of LSR J1835+3259 resembles the spectrum of mid/late-type M-dwarf stars relatively well, but it is distinct from a spectrum expected from Jupiter-like auroral processes.

  19. Kinetic description of nuclear photoabsorption process

    International Nuclear Information System (INIS)

    Ferreira Filho, L.G.

    1986-01-01

    A phenomenological model for small amplitude nuclear vibrations is presented. The model separates explicitly the collective degree of freedom and considers its interaction with unspecified intrinsic degrees of freedom. The nuclear response function was calculated, including quantum correlation effects up to second order in the coupling potential, and compared with the usual harmonic approximation for the density fluctuation. The coupling between the two systems is treated with a phenomenological ansatz. The parameters are adjusted so as to reproduce the experimental total photoabsorption cross section for two nuclei ( 208 Pb, 238 U). It is shown that the inclusion of correlations may strongly alter the form of this curve as compared to the usual Iorentz curve. In the semiclassical limit the effective dynamics of the collective degree of freedom is shown to obey a Fokker-Planck equation. (Author) [pt

  20. Importance of Vibronic Effects in the UV-Vis Spectrum of the 7,7,8,8-Tetracyanoquinodimethane Anion.

    Science.gov (United States)

    Tapavicza, Enrico; Furche, Filipp; Sundholm, Dage

    2016-10-11

    We present a computational method for simulating vibronic absorption spectra in the ultraviolet-visible (UV-vis) range and apply it to the 7,7,8,8-tetracyanoquinodimethane anion (TCNQ - ), which has been used as a ligand in black absorbers. Gaussian broadening of vertical electronic excitation energies of TCNQ - from linear-response time-dependent density functional theory produces only one band, which is qualitatively incorrect. Thus, the harmonic vibrational modes of the two lowest doublet states were computed, and the vibronic UV-vis spectrum was simulated using the displaced harmonic oscillator approximation, the frequency-shifted harmonic oscillator approximation, and the full Duschinsky formalism. An efficient real-time generating function method was implemented to avoid the exponential complexity of conventional Franck-Condon approaches to vibronic spectra. The obtained UV-vis spectra for TCNQ - agree well with experiment; the Duschinsky rotation is found to have only a minor effect on the spectrum. Born-Oppenheimer molecular dynamics simulations combined with calculations of the electronic excitation energies for a large number of molecular structures were also used for simulating the UV-vis spectrum. The Born-Oppenheimer molecular dynamics simulations yield a broadening of the energetically lowest peak in the absorption spectrum, but additional vibrational bands present in the experimental and simulated quantum harmonic oscillator spectra are not observed in the molecular dynamics simulations. Our results underline the importance of vibronic effects for the UV-vis spectrum of TCNQ - , and they establish an efficient method for obtaining vibronic spectra using a combination of linear-response time-dependent density functional theory and a real-time generating function approach.

  1. Exclusion of UV-B radiation from normal solar spectrum on the growth of mung bean and maize

    International Nuclear Information System (INIS)

    Pal, M.; Sharma, A.; Abrol, Y.P.; Sengupta, U.K.

    1997-01-01

    The increase in UV-B radiation due to depletion of the ozone layer has potentially harmful effects on plant growth and performance. The bulk of these studies conducted in growth chambers, greenhouses or in the field use different types of exposure systems which may be responsible for differences in the sensitivity of a crop to UV-B radiation. A field study using selective filters to remove the UV-B portion of the solar spectrum was conducted with mung bean (a dicotyledonous C 3 plant) and maize (a monocotyledonous C 4 plant) to determine the sensitivity of these crop plants to ambient UV-B levels without disturbing the microenvironment. Mung bean was found to be sensitive to ambient UV-B levels in terms of leaf area development, plant height attained and net photosynthesis, while maize was found to be unaffected by ambient UV-B levels (22.8 |GmW cm −2 nm −1 ) found in Delhi, India (28°38′N, 77°13′E). The level of ambient UV-B radiation thus appears to be inhibitory for optimal growth of plants, especially dicotyledonous mung bean. (author)

  2. Intermediate-energy nuclear photoabsorption and the pion optical potential

    International Nuclear Information System (INIS)

    Christillin, P.

    1984-01-01

    Nuclear photoabsorption around the pion threshold is schematised as photoproduction of a pion which undergoes final-stae interaction with the nucleus, accounted for by the pion optical potential. It is shown that real pion photoproduction and exchange effects are naturally described by the same mechanism with a non-static pion. The complementarity of photoabsorption to pion physics and its usefulness in gaining new information about pion-nucleus dynamics are stressed. (author)

  3. A study of the valence shell electronic states of s-triazine by photoabsorption spectroscopy and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Holland, D.M.P., E-mail: david.holland@stfc.ac.uk [Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Shaw, D.A. [Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Stener, M.; Decleva, P. [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri, I-34127 Trieste (Italy); Consorzio Interuniversitario Nazionale per la Scienze e Tecnologia dei Materiali, INSTM, Unità di Trieste (Italy); CNR-IOM, Trieste (Italy); Coriani, S. [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri, I-34127 Trieste (Italy); Consorzio Interuniversitario Nazionale per la Scienze e Tecnologia dei Materiali, INSTM, Unità di Trieste (Italy); Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C (Denmark)

    2016-09-30

    Highlights: • The valence shell photoabsorption spectrum of s-triazine has been measured. • Electronic structure calculated with TDDFT and coupled cluster approaches. • Assignments proposed for Rydberg and valence states. • Mixing between Rydberg and valence states important. - Abstract: The absolute photoabsorption cross section of s-triazine has been measured between 4 and 40 eV, and is dominated by bands associated with valence states. Structure due to Rydberg excitations is both weak and irregular. Jahn-Teller interactions affect the vibronic structure observed in the Rydberg absorption bands due to excitation from the 1e″ or 6e′ orbitals. The interpretation of the experimental spectrum has been guided by transition energies and oscillator strengths, for Rydberg and valence states, calculated with the time-dependent version of density functional theory and with the coupled cluster linear response approach. The theoretical studies indicate that Rydberg/Rydberg and Rydberg/valence mixing is important.

  4. Photoabsorption spectra of (Mo/W)@Au12Si60 clusters from time-dependent DFT calculations

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-11-14

    The electronic structure and photoabsorption spectrum of encapsulated (Mo/W)@Au12Si60 clusters are theoretically investigated via static and time-dependent density functional theory. The photoabsorption spectrum is calculated both at the scalar relativistic and spin-orbit coupling levels. The encapsulated (Mo/W)@Au12 clusters interact with the Si and thus stabilize the Si60 cage. The spin-orbit coupling strongly affects the optical properties of (Mo/W)@Au12 clusters as it leads to a splitting of spectral lines together with an intensity redistribution, whereas the spectra of (Mo/W)@Au12Si60 clusters show hardly any difference. The nanoscale properties thus can be tuned by choosing the endohedral metal atom, while keeping the optical properties unaffected. © 2013 American Chemical Society.

  5. Photoabsorption spectra of (Mo/W)@Au12Si60 clusters from time-dependent DFT calculations

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2013-01-01

    The electronic structure and photoabsorption spectrum of encapsulated (Mo/W)@Au12Si60 clusters are theoretically investigated via static and time-dependent density functional theory. The photoabsorption spectrum is calculated both at the scalar relativistic and spin-orbit coupling levels. The encapsulated (Mo/W)@Au12 clusters interact with the Si and thus stabilize the Si60 cage. The spin-orbit coupling strongly affects the optical properties of (Mo/W)@Au12 clusters as it leads to a splitting of spectral lines together with an intensity redistribution, whereas the spectra of (Mo/W)@Au12Si60 clusters show hardly any difference. The nanoscale properties thus can be tuned by choosing the endohedral metal atom, while keeping the optical properties unaffected. © 2013 American Chemical Society.

  6. Merely Measuring the UV-Visible Spectrum of Gold Nanoparticles Can Change Their Charge State.

    Science.gov (United States)

    Navarrete, Jose; Siefe, Chris; Alcantar, Samuel; Belt, Michael; Stucky, Galen D; Moskovits, Martin

    2018-02-14

    chemical potential due to the entropy increase resulting from the conversion of the plasmon's energy to heat. We conclude that even the act of registering the spectrum of nanoparticles is at times sufficient to alter their charge densities and hence their UV-visible spectra.

  7. K-SHELL PHOTOABSORPTION OF MAGNESIUM IONS

    Energy Technology Data Exchange (ETDEWEB)

    Hasoğlu, M. F. [Department of Computer Engineering, Hasan Kalyoncu University, 27100 Sahinbey, Gaziantep (Turkey); Abdel-Naby, Sh. A. [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Gatuzz, E.; Mendoza, C. [Centro de Física, Instituto Venezolano de Investigaciones Científicas, Caracas 1020 (Venezuela, Bolivarian Republic of); García, J. [Harvard-Smithsonian Center for Astrophysics, MS-6, 60 Garden Street, Cambridge, MA 02138 (United States); Kallman, T. R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gorczyca, T. W. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008-5252 (United States)

    2014-09-01

    X-ray photoabsorption cross sections have been computed for all magnesium ions with three or more electrons using the R-matrix method. A comparison with other available data for Mg II-Mg X shows good qualitative agreement in the resultant resonance shapes. However, for the lower ionization stages, and for singly ionized Mg II in particular, the previous R-matrix results overestimate the K-edge position due to the neglect of important orbital relaxation effects, and a global shift downward in photon energy of those cross sections is therefore warranted. We have found that the cross sections for Mg I and Mg II are further complicated by the M-shell (n = 3) occupancy. As a result, the treatment of spectator Auger decay of 1s → np resonances using a method based on multichannel quantum defect theory and an optical potential becomes problematic, making it necessary to implement an alternative, approximate treatment of Auger decay for neutral Mg I. The new cross sections are used to fit the Mg K edge in XMM-Newton spectra of the low-mass X-ray binary GS 1826-238, where most of the interstellar Mg is found to be in ionized form.

  8. Cell thickness of UV absorption by the cell: relation to UV action spectrum shift in mammalian cells in culture

    International Nuclear Information System (INIS)

    Sakharov, V.H.; Voronkova, L.N.; Blokhin, A.V.

    1985-01-01

    By means of reconstruction of series half - thin transverse sections the three - dimensional morphometry of SPEV cells for a series of their specific states in culture is performed: for exponential growth in a monolayer, in a merged monolayer, in the mitosis phase, for giant cells and suspension cells. In the monolayer the cell thickness in its central part depended mainly on the nucleus thickness and in average changed but slightly despite a wide range of changes in volumes of nuclei and cells and their density in culture. The cell thickness has noticeably increased in mitosis. For the above states of cells UV radiation absorption spectra are determined. It is shown that a certain shift of action spectrus of death of mammalian cells as compared with that for bacterial cell can be a seguence of selfshielding and not differences in the nature of active chromophores

  9. Quasimonochromatic x-ray source using photoabsorption-edge transition radiation

    International Nuclear Information System (INIS)

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Harris, J.L.; Maruyama, X.K.; Bergstrom, J.C.; Caplan, H.S.; Silzer, R.M.; Skopik, D.M.

    1991-01-01

    By designing transition radiators to emit x rays at the foil material's K-, L-, or M-shell photoabsorption edge, the x-ray spectrum is narrowed. The source is quasimonochromatic, directional, and intense and uses an electron beam whose energy is considerably lower than that needed for synchrotron sources. Depending upon the selection of foil material, the radiation can be produced wherever there is a photoabsorption edge. In this paper we report the results of the measurement of the x-ray spectrum from a transition radiator composed of 10 foils of 2-μm titanium and exposed to low-current, 90.2-MeV electrons. The measured band of emission was from 3.2 to 5 keV. In addition, a measurment was performed of the total power from a transition radiator composed of 18 foils of 2.0-μm copper exposed to a high-average-current electron beam of 40 μA and at energies of 135, 172, and 200 MeV. The maximum measured power was 4.0 mW. The calculated band of emission was from 4 to 9 keV

  10. Action spectrum and mechanisms of UV radiation-induced injury in lupus erythematosus

    International Nuclear Information System (INIS)

    Kochevar, I.E.

    1985-01-01

    Photosensitivity associated with lupus erythematosus (LE) is well established. The photobiologic basis for this abnormal response to ultraviolet radiation, however, has not been determined. This paper summarizes the criteria for elucidating possible photobiologic mechanisms and reviews the literature relevant to the mechanism of photosensitivity in LE. In patients with LE, photosensitivity to wavelengths shorter than 320 nm has been demonstrated; wavelengths longer than 320 nm have not been adequately evaluated. DNA is a possible chromophore for photosensitivity below 320 nm. UV irradiation of skin produces thymine photodimers in DNA. UV-irradiated DNA is more antigenic than native DNA and the antigenicity of UV-irradiated DNA has been proposed, but not proven, to be involved in the development of clinical lesions. UV irradiation of mice previously injected with anti-UV-DNA antibodies produces Ig deposition and complement fixation that appears to be similar to the changes seen in lupus lesions. Antibodies to UV-irradiated DNA occur in the serum of LE patients although a correlation between antibody titers and photosensitivity was not observed. Defective repair of UV-induced DNA damage does not appear to be a mechanism for the photosensitivity in LE. Other mechanisms must also be considered. The chromophore for photosensitivity induced by wavelengths longer than 320 nm has not been investigated in vivo. In vitro studies indicate that 360-400 nm radiation activates a photosensitizing compound in the lymphocytes and serum of LE patients and causes chromosomal aberrations and cell death. The mechanism appears to involve superoxide anion

  11. A Near-Threshold Shape Resonance in the Valence-Shell Photoabsorption of Linear Alkynes

    Energy Technology Data Exchange (ETDEWEB)

    Jacovella, U.; Holland, D. M. P.; Boyé-Péronne, S.; Gans, Bérenger; de Oliveira, N.; Ito, K.; Joyeux, D.; Archer, L. E.; Lucchese, R. R.; Xu, Hong; Pratt, S. T.

    2015-12-17

    The room-temperature photoabsorption spectra of a number of linear alkynes with internal triple bonds (e.g., 2-butyne, 2-pentyne, and 2- and 3-hexyne) show similar resonances just above the lowest ionization threshold of the neutral molecules. These features result in a substantial enhancement of the photoabsorption cross sections relative to the cross sections of alkynes with terminal triple bonds (e.g., propyne, 1-butyne, 1-pentyne,...). Based on earlier work on 2-butyne [Xu et al., J. Chem. Phys. 2012, 136, 154303], these features are assigned to excitation from the neutral highest occupied molecular orbital (HOMO) to a shape resonance with g (l = 4) character and approximate pi symmetry. This generic behavior results from the similarity of the HOMOs in all internal alkynes, as well as the similarity of the corresponding g pi virtual orbital in the continuum. Theoretical calculations of the absorption spectrum above the ionization threshold for the 2- and 3-alkynes show the presence of a shape resonance when the coupling between the two degenerate or nearly degenerate pi channels is included, with a dominant contribution from l = 4. These calculations thus confirm the qualitative arguments for the importance of the l = 4 continuum near threshold for internal alkynes, which should also apply to other linear internal alkynes and alkynyl radicals. The 1-alkynes do not have such high partial waves present in the shape resonance. The lower l partial waves in these systems are consistent with the broader features observed in the corresponding spectra.

  12. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

    2017-01-01

    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...

  13. Kinetic description of the total photoabsorption cross section: correlation effects

    International Nuclear Information System (INIS)

    Ferreira Filho, L.G.; Nemes, M.C.

    1986-02-01

    It is shown that the inclusion of correlation effects in describing the nuclear photoabsorption cross section leads to a Breit-Wigner type curve with energy dependent width. It is also shown that a very slow energy dependence is enough to reproduce the data up to ∼ 139 MeV. (Author) [pt

  14. The intrinsic far-UV spectrum of the high-redshift quasar B1422+231

    Science.gov (United States)

    O'Dowd, M.; Bate, N. F.; Webster, R. L.; Labrie, K.; King, A. L.; Yong, S.-. Y.

    2018-02-01

    We present new spectroscopy of the z = 3.62 gravitationally lensed quasar B1422+117 from the Gemini North GMOS integral field spectrograph. We observe significant differential magnifications between the broad emission lines and the continuum, as well as across the velocity structure of the Lyman-α line. We take advantage of this differential microlensing to algebraically decompose the quasar spectrum into the absorbed broad emission line and absorbed continuum components. We use the latter to derive the intrinsic Ly α forest absorption spectrum. The proximity effect is clearly detected, with a proximity zone edge of 8.6-17.3 Mpc from the quasar, implying (perhaps intermittent) activity over at least 28 Myr. The Ly α line profile exhibits a blue excess that is inconsistent with a symmetric fit to the unabsorbed red side. This has important implications for the use of this fitting technique in estimating the absorbed blue Ly α wings of Gunn-Peterson trough quasars.

  15. Macroscopic local-field effects on photoabsorption processes

    International Nuclear Information System (INIS)

    Ma Xiaoguang; Gong Yubing; Wang Meishan; Wang Dehua

    2008-01-01

    The influence of the local-field effect on the photoabsorption cross sections of the atoms which are embedded in the macroscopic medium has been studied by a set of alternative expressions in detail. Some notes on the validity of some different local-field models used to study the photoabsorption cross sections of atoms in condensed matter have been given for the first time. Our results indicate that the local fields can have substantial and different influence on the photoabsorption cross section of atoms in condensed matter for different models. Clausius-Mossotti model and Onsager model have proved to be more reasonable to describe the local field in gas, liquid, or even some simple solid, while Glauber-Lewenstein model probably is wrong in these conditions except for the ideal gas. A procedure which can avoid the errors introduced by Kramers-Kronig transformation has been implemented in this work. This procedure can guarantee that the theoretical studies on the local field effects will not be influenced by the integral instability of the Kramers-Kronig transformation

  16. Workshop report on new directions in soft x-ray photoabsorption

    International Nuclear Information System (INIS)

    Bartlett, R.; Del Grande, N.K.; Lindau, I.; Manson, S.; Merts, A.L.; Pratt, R.

    1984-01-01

    The Workshop Report integrates what was said at the Workshop on New Directions in Soft X-Ray Photoabsorption, which focused on the region from 100 eV to 10 keV. The report clarifies the current state of theory and experiment and identifies the opportunities which new theoretical methods and experimental facilities could be expected to provide. The understanding of photoabsorption (which requires experimental photoabsorption cross section data) is a key to understanding the properties and behavior of atoms, molecules and solids. The Workshop participants were forty-three physicists and quantum chemists, from twenty-four institutions in four countries, all interested in photoabsorption from different perspectives

  17. Development of aluminum gallium nitride based optoelectronic devices operating in deep UV and terahertz spectrum ranges

    Science.gov (United States)

    Zhang, Wei

    In this research project I have investigated AlGaN alloys and their quantum structures for applications in deep UV and terahertz optoelectronic devices. For the deep UV emitter applications the materials and devices were grown by rf plasma-assisted molecular beam epitaxy on 4H-SiC, 6H-SiC and c-plane sapphire substrates. In the growth of AlGaN/AlN multiple quantum wells on SiC substrates, the AlGaN wells were grown under excess Ga, far beyond than what is required for the growth of stoichiometric AlGaN films, which resulted in liquid phase epitaxy growth mode. Due to the statistical variations of the excess Ga on the growth front we found that this growth mode leads to films with lateral variations in the composition and thus, band structure potential fluctuations. Transmission electron microscopy shows that the wells in such structures are not homogeneous but have the appearance of quantum dots. We find by temperature dependent photoluminescence measurements that the multiple quantum wells with band structure potential fluctuations emit at 240 nm and have room temperature internal quantum efficiency as high as 68%. Furthermore, they were found to have a maximum net modal optical gain of 118 cm-1 at a transparency threshold corresponding to 1.4 x 1017 cm-3 excited carriers. We attribute this low transparency threshold to population inversion of only the regions of the potential fluctuations rather than of the entire matrix. Some prototype deep UV emitting LED structures were also grown by the same method on sapphire substrates. Optoelectronic devices for terahertz light emission and detection, based on intersubband transitions in III-nitride semiconductor quantum wells, were grown on single crystal c-plane GaN substrates. Growth conditions such the ratio of group III to active nitrogen fluxes, which determines the appropriate Ga-coverage for atomically smooth growth without requiring growth interruptions were employed. Emitters designed in the quantum cascade

  18. Organic and inorganic interpretations of the martian UV-IR reflectance spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Pang, K D; Ajello, J M [Jet Propulsion Lab., Pasadena, CA (USA); Chun, S F.S. [California Univ., San Francisco (USA). School of Medicine; Nansheng, Z [Beijing Planetarium (China); Minji, L [Beijing Glass Institute (China)

    1982-01-07

    The Viking gas chromatography-mass spectrometer analysis of martian soil samples are discussed, in particular why no organic molecules were detected at the landing sites, whether the sterility of the two sites is representative of the entire planet and if there are locations on Mars more conducive to the formation and preservation of organics. The destruction of organic compounds has been simulated in Mars-like laboratory conditions and the possible planetwide destructive mechanism considered. The UV and IR reflectance spectra of Mars has been re-examined for any evidence of organic molecules and an upper limit on the organic carbon content of average martian soil has been set. The results reveal that the average martian soil is organic-poor, makes an unfavourable habitat for life forms based on carbon chemistry, and there is no reason to believe that organic molecules are preferentially preserved anywhere on the planet.

  19. Organic and inorganic interpretations of the martian UV-IR reflectance spectrum

    International Nuclear Information System (INIS)

    Pang, K.D.; Ajello, J.M.; Chun, S.F.S.; Minji, L.

    1982-01-01

    The Viking gas chromatography-mass spectrometer analysis of martian soil samples are discussed, in particular why no organic molecules were detected at the landing sites, whether the sterility of the two sites is representative of the entire planet and if there are locations on Mars more conducive to the formation and preservation of organics. The destruction of organic compounds has been simulated in Mars-like laboratory conditions and the possible planetwide destructive mechanism considered. The UV and IR reflectance spectra of Mars has been re-examined for any evidence of organic molecules and an upper limit on the organic carbon content of average martian soil has been set. The results reveal that the average martian soil is organic-poor, makes an unfavourable habitat for life forms based on carbon chemistry, and there is no reason to believe that organic molecules are preferentially preserved anywhere on the planet. (U.K.)

  20. Abundance analysis from the UV spectrum of the He-w star HR 6000

    International Nuclear Information System (INIS)

    Castelli, F.; Cornachin, M.; Morossi, C.; Hack, M.

    1984-01-01

    A high resolution spectrum of the He-w star HR 6000, covering the SW and LW regions, has been analysed. A fully line-blanketed model atmosphere with parameters Tsub(e) = 14000 K, log g = 4, microturbulence xi = 2 km.s -1 has been adopted. This model is in agreement with the photometric data and yields the same abundance for the Fe II and Fe III ions. By using the synthetic spectrum method we compared the observed lines with the computed ones. We find an underabundance of C, Al Si, Mg, S, Sc, Co, Ni, Zn and an overabundance of Be, P, Cl, Ti, Mn, Fe, Ga. B, O, Cr have nearly solar abundances. Circumstellar (or interstellar) shortward-shifted components affect the strong resonance lines of the following ions: C II(1) lambda 1334.535, O I(2) lambda 1302.074,Mg II(1) lambda 2795.523, lambda 2802.698, Si II(3) lambda 1304.369, Fe II(1) lambda 2599.395

  1. Explicit Hilbert-space representations of atomic and molecular photoabsorption spectra: Computational studies of Stieltjes-Tchebycheff functions

    International Nuclear Information System (INIS)

    Hermann, M.R.; Langhoff, P.W.

    1983-01-01

    Explicit Hilbert-space techniques are reported for construction of the discrete and continuum Schroedinger states required in atomic and molecular photoexcitation and/or photoionization studies. These developments extend and clarify previously described moment-theory methods for determinations of photoabsorption cross sections from discrete basis-set calculations to include explicit construction of underlying wave functions. The appropriate Stieltjes-Tchebycheff excitation and ionization functions of nth order are defined as Radau-type eigenstates of an appropriate operator in an n-term Cauchy-Lanczos basis. The energies of these states are the Radau quadrature points of the photoabsorption cross section, and their (reciprocal) norms provide the corresponding quadrature weights. Although finite-order Stieltjes-Tchebycheff functions are L 2 integrable, and do not have asymptotic spatial tails in the continuous spectrum, the Radau quadrature weights nevertheless provide information for normalization in the conventional Dirac delta-function sense. Since one Radau point can be placed anywhere in the spectrum, appropriately normalized convergent approximations to any of the discrete or continuum Schroedinger states are obtained from the development. Connections with matrix partitioning methods are established, demonstrating that nth-order Stieltjes-Tchebycheff functions are optical-potential solutions of the matrix Schroedinger equation in the full Cauchy-Lanczos basis

  2. Energy spectrum of flares of the UV Cet stars and physical measunings of several statistical characteristics of these stars

    International Nuclear Information System (INIS)

    Gershberg, R.E.

    1985-01-01

    Accounting the observed power character of the energy spectrum of flares of the UV Cet-type stars, several statistical characterisitics of there stars are considered. It is shown that a mean amplitude of flares is mainly determined with an amplitude of the faintest flare that can be registered at the star under consideration and therefore - contrary to tradition - the mean flare amplitude cannot be used as a measure of a flare activity of the star. Mean frequencuy of flares registered at a flare star dependes statisticaally certainly ona an absolute magneitude of the star - contary to wide spread belief, true mean frequencies are higher at brighter stars. On the basis of the Cataloque of flare stars in Pleiades by Haro, Chavira and Gonzalez a luminosity function of therese stars is constructed. Using this function and the revealed dependence of flare mean frequencies on stellar absolute magnitudes, a distribution of flare stars in Pleiades along flare mean frequencies is constructed. This shows that the cluster contains flare stars with mean frequencies of photographically registered flares from 10 -4 to 10 -2 hour -1 or within even narrower interval of frequencies and the total number of such stars in the cluster exceeds 1100

  3. Spectrum

    DEFF Research Database (Denmark)

    Høgfeldt Hansen, Leif

    2016-01-01

    The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum.......The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum....

  4. Compton scattering from nuclei and photo-absorption sum rules

    International Nuclear Information System (INIS)

    Gorchtein, Mikhail; Hobbs, Timothy; Londergan, J. Timothy; Szczepaniak, Adam P.

    2011-01-01

    We revisit the photo-absorption sum rule for real Compton scattering from the proton and from nuclear targets. In analogy with the Thomas-Reiche-Kuhn sum rule appropriate at low energies, we propose a new 'constituent quark model' sum rule that relates the integrated strength of hadronic resonances to the scattering amplitude on constituent quarks. We study the constituent quark model sum rule for several nuclear targets. In addition, we extract the α=0 pole contribution for both proton and nuclei. Using the modern high-energy proton data, we find that the α=0 pole contribution differs significantly from the Thomson term, in contrast with the original findings by Damashek and Gilman.

  5. Photoabsorption spectra in the perturbative regime for atoms in crossed electric and magnetic fields

    International Nuclear Information System (INIS)

    Marxer, H.; Moser, I.; O'Mahony, P.F.; Mota-Furtado, F.

    1994-01-01

    We calculate photoabsorption spectra of atoms in crossed electric and magnetic fields using a truncated basis of Coulomb eigenfunctions. The method yields spectra in the regime where inter-n-mixing is not dominant and allows for the treatment of non-hydrogenic atoms via a simple recourse to quantum defects. We compare results for hydrogen to those obtained in second order perturbation theory where the residual degeneracy left in first order perturbation theory is completely lifted and we show that only a very small basis size is needed to achieve convergence to within the accuracy of second order perturbation theory. In the case of lithium the coupling of an incomplete hydrogen-like manifold to states with non-negligible quantum defects substantially modifies the spectra obtained in comparison to the purely hydrogenic spectra. In the inter-n-mixing regime we also compare our convoluted results directly with an experimental spectrum for hydrogen and find good agreement below the saddle point. (Author)

  6. The sun protection factor (SPF) inadequately defines broad spectrum photoprotection: demonstration using skin reconstructed in vitro exposed to UVA, UVBor UV-solar simulated radiation.

    Science.gov (United States)

    Bernerd, Françoise; Vioux, Corinne; Lejeune, François; Asselineau, Daniel

    2003-01-01

    Wavelength specific biological damage has been previously identified in human skin reconstructed in vitro. Sunburn cell and pyrimidine dimers were found after UVB exposure, and alterations of dermal fibroblasts after UVA exposure. These damages permitted us to discriminate UVB and UVA single absorbers. The present study shows that these biological effects can be obtained simultaneously by a combined UVB + UVA exposure using ultraviolet solar simulated light (UV-SSR), which represents a relevant UV source. In addition, the protection afforded by two broad spectrum sunscreen complex formulations was assessed after topical application. These two formulations displayed the same sun protection factor but different UVA protection factors determined by the persistent pigment darkening (PPD) method. Dose response experiments of UVA or UV-SSR showed that the preparation with the highest PF-UVA provided a better protection with regard to dermal damage compared to the other formulation. Using an original UVB source to obtain the UVB portion of SSR spectrum, the preparations provided the same protection. This study strikingly illustrates the fact that the photoprotection afforded by two sunscreen formulations having similar SPF values is not equal with regard to dermal damage related to photoaging.

  7. Specific UV-induced mutation spectrum in the p53 gene of skin tumors from DNA-repair-deficient xeroderma pigmentosum patients

    International Nuclear Information System (INIS)

    Dumaz, N.; Drougard, C.; Sarasin, A.; Daya-Grosjean, L.

    1993-01-01

    The UV component of sunlight is the major carcinogen involved in the etiology of skin cancers. The authors have studied the rare, hereditary syndrome xeroderma pigmentosum (XP), which is characterized by a very high incidence of cutaneous tumors on exposed skin at an early age, probably due to a deficiency in excision repair of UV-induced lesions. It is interesting to determine the UV mutation spectrum in XP skin tumors in order to correlate the absence of repair of specific DNA lesions and the initiation of skin tumors. The p53 gene is frequently mutated in human cancers and represents a good target for studying mutation spectra since there are >100 potential sites for phenotypic mutations. Using reverse transcription-PCR and single-strand conformation polymorphism to analyze >40 XP skin tumors (mainly basal and squamous cell carcinomas), the authors have found that 40% (17 out of 43) contained at least one point mutation on the p53 gene. All the mutations were located at dipyrimidine sites, essentially at CC sequences, which are hot spots for UV-induced DNA lesions. Sixty-one percent of these mutations were tandem CC → TT mutations considered to be unique to UV-induced lesions; these mutations are not observed in internal human tumors. All the mutations, except two, must be due to translesion synthesis of unrepaired dipyrimidine lesions left on the nontranscribed strand. These results show the existence of preferential repair of UV lesions [either pyrimidine dimers or pyrimidine-pyrimidone (6-4) photoproducts] on the transcribed strand in human tissues

  8. Sunscreens with broad-spectrum absorption decrease the trans TO cis photoisomerization of urocanic acid in the human stratum corneum after multiple UV light exposures

    International Nuclear Information System (INIS)

    Krien, P.M.; Moyal, D.

    1994-01-01

    The trans to cis photoisomerization of urocanic acid (UCA) in skin is considered to play an important role in the mechanism of immunosuppression. We have investigated the effects of skin type and various sunscreens with low sun protection factor (SPF) on the UV-induced cis-UCA formation in human skin after exposure to artificial UV light. The rate of cis-UCA formation depends little on the skin type and is reduced by topical application of sunscreens. The rate of cis-UCA formation decreases with increasing SPF and only broad-spectrum, highly protective sunscreens offer protection against the UV-induced formation of cis-UCA, which accumulates in the stratum corneum after multiple UV exposures. A theoretical approach to estimate the distribution of cis-UCA after irradiation indicates that this compound may diffuse into the deeper layers of the epidermis with D ∼ 10 -17 m 2 /s, and that its elimination from the stratum corneum is mainly due to desquamation. (author)

  9. Modeling photoabsorption of the asFP595 chromophore.

    Science.gov (United States)

    Bravaya, Ksenia B; Bochenkova, Anastasia V; Granovsky, Alexander A; Savitsky, Alexander P; Nemukhin, Alexander V

    2008-09-18

    The fluorescent protein asFP595 is a promising photoswitchable biomarker for studying processes in living cells. We present the results of a high level theoretical study of photoabsorption properties of the model asFP595 chromophore molecule in biologically relevant protonation states: anionic, zwitterionic, and neutral. Ground state equilibrium geometry parameters are optimized in the PBE0/(aug)-cc-pVDZ density functional theory approximation. An augmented version of multiconfigurational quasidegenerate perturbation theory (aug-MCQDPT2) following the state-averaged CASSCF/(aug)-cc-pVDZ calculations is used to estimate the vertical S0-S1 excitation energies for all chromophore species. An accuracy of this approach is validated by comparing the computed estimates of the S0-S1 absorption maximum of the closely related chromophore from the DsRed protein to the known experimental value in the gas phase. An influence of the CASSCF active space on the aug-MCQDPT2 excitation energies is analyzed. The zwitterionic form of the asFP595 chromophore is found to be the most sensitive to a particular choice and amount of active orbitals. This observation is explained by the charge-transfer type of the S0-S1 transition involving the entire conjugated pi-electron system for the zwitterionic protonation state. According to the calculation results, the anionic form in the trans conformation is found to possess the most red-shifted absorption band with the maximum located at 543 nm. The bands of the zwitterionic and neutral forms are considerably blue-shifted compared to those of the anionic form. These conclusions are at variance with the results obtained in the TDDFT approximation for the asFP595 chromophore. The absorption wavelengths computed in the aug-MCQDPT2/CASSCF theory are as follows: 543 (535), 470 (476), and 415 (417) nm for the anionic, zwitterionic, and neutral forms of the trans and cis (in parentheses) isomers of the asFP595 chromophore. These data can be used as a

  10. Determination of mixture valence plutonium and multicomponent by computer resolution analysis of absorption spectrum (UV/VIS/NIR) (CRAAS)

    International Nuclear Information System (INIS)

    Zhuang Weixin; Ye Guoan; Huang Lifeng; Sun Hongfang; Zhao Yanju

    1996-09-01

    A spectrophotometry has been developed which can directly determine a multi-component sample by spectrophotometry without any chemical separation. CRAAS (Computer Resolution Analysis of Absorption Spectrum) has been reported. It is different from the previous spectrophotometry depending on only one or several special absorption peak. The CRAAS deals with the whole region of absorption spectrum by mathematical statistics. So CRAAS has higher accuracy, stronger power and very high resolution. The trouble comes from overlap of different spectrum in each other has been solved because CRAAS depends on the whole spectrum. As long as two spectra have different shape, their concentrations can be determined even their special absorption peaks are seriously overlapped. The accuracy is about +-5%. (2 refs., 7 figs., 8 tabs.)

  11. The UV-A and visible solar irradiance spectrum: inter-comparison of absolutely calibrated, spectrally medium resolution solar irradiance spectra from balloon- and satellite-borne measurements

    Directory of Open Access Journals (Sweden)

    W. Gurlit

    2005-01-01

    Full Text Available Within the framework of the ENVISAT/-SCIAMACHY satellite validation, solar irradiance spectra are absolutely measured at moderate resolution in the UV/visible spectral range (in the UV from 316.7-418 nm and the visible from 400-652 nm at a full width half maximum resolution of 0.55 nm and 1.48 nm, respectively from aboard the azimuth-controlled LPMA/DOAS balloon gondola at around 32 km balloon float altitude. After accounting for the atmospheric extinction due to Rayleigh scattering and gaseous absorption (O3 and NO2, the measured solar spectra are compared with previous observations. Our solar irradiance spectrum perfectly agrees within +0.03% with the re-calibrated Kurucz et al. (1984 solar spectrum (Fontenla et al., 1999, called MODTRAN 3.7 in the visible spectral range (415-650 nm, but it is +2.1% larger in the (370-415 nm wavelength interval, and -4% smaller in the UV-A spectral range (316.7-370 nm, when the Kurucz spectrum is convolved to the spectral resolution of our instrument. Similar comparisons of the SOLSPEC (Thuillier et al., 1997, 1998a, b and SORCE/SIM (Harder et al., 2000 solar spectra with MODTRAN 3.7 confirms our findings with the values being -0.5%, +2%, and -1.4% for SOLSPEC -0.33%, -0.47%, and -6.2% for SORCE/SIM, respectively. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (- re-calibrated by the University of Bremen - with MODTRAN 3.7 indicates an agreement within -0.4% in the visible spectral range (415-585 nm, -1.6% within the 370-415 nm, and -5.7% within 325-370 nm wavelength interval, in agreement with the results of the other sensors. In agreement with findings of Skupin et al. (2002 our study emphasizes that the present ESA SCIAMACHY level 1 calibration is systematically +15% larger in the considered wavelength intervals when compared to all available other solar irradiance measurements.

  12. Use of the Green function method for calculation of cross section of x-ray photoabsorption for solids

    International Nuclear Information System (INIS)

    Kozhakhmetov, S.K.

    1996-01-01

    Possibility of Green formalism use for calculation of photoabsorption of high-energy x-ray radiation is shown. Analytical expression for photoabsorption cross section is carried out. It does not contains wave functions in explicit form responding to finite states of photoelectron. 5 refs

  13. Singlet and doublet states UV-vis spectrum and electronic properties of 3-methylchrysene and 4-methylchrysene in glass matrix.

    Science.gov (United States)

    Husain, Mudassir M; Tandon, H C; Varadwaj, Pradeep R

    2008-03-01

    The ultraviolet-visual spectrum of 3-methylchrysene, 4-methylchrysene and their radical cations formed by ultraviolet radiations, were measured in glass matrix at the room temperature. In the measured singlet state spectrum we were able to identify the alpha, p, beta, beta' (Clar's) or (1)L(b), (1)L(a)(1)B(b), (1)B(a) (Platt's notation) bands. The presence of alpha, beta or (1)L(b), (1)B(b) was confirmed by calculating their wavelength ratio lambda(alpha)/lambda(beta). Since matrix induces perturbation in the measured spectrum; it becomes necessary to take into account the perturbation while computing the spectrum. An effort has been made in this work to simulate the electronic spectrum in the same environment as is measured. This study presents the first calculated spectrum of these systems and their cations in glass matrix by semi empirical methods. To observe the magnitude of perturbation and hence to see the spectral shift in glass matrix, the spectrum was calculated in the free state as well. Spectral properties such as frontier orbitals gap, dipole moment, mean polarizabilities and its tensors were also computed both in glass matrix and free state using semiemperical method. The measured bands of 3-methylchrysene cation at wavelength 416.50 and 473.85 nm closely match with the available diffuse intersteallar bands (DIBs) at 417.55 and 472.64 nm, respectively. Also the observed 474.85 nm band of 4-methylchrysene cation matches the DIB at 476.00 nm.

  14. Autoionization resonances in the photoabsorption spectra of Fe{sup n+} iron ions

    Energy Technology Data Exchange (ETDEWEB)

    Konovalov, A. V., E-mail: alkonvit@yandex.ru; Ipatov, A. N., E-mail: andrei-ipatov@mail.ru [Peter the Great St. Petersburg State Polytechnic University (Russian Federation)

    2016-11-15

    The photoabsorption cross sections of a neutral iron atom, as well as positive Fe{sup +} and Fe{sup 2+} ions, are calculated in the relativistic random-phase approximation with exchange in the energy range 20–160 eV. The wavefunctions of the ground and excited states are calculated in the single-configuration Hartree–Fock–Dirac approximation. The resultant photoabsorption spectra are compared with experimental data and with the results of calculations based on the nonrelativistic spin-polarized version of the random-phase approximation with exchange. Series of autoionization resonance peaks, as well as giant autoionization resonance lines corresponding to discrete transitions 3p → 3d, are clearly observed in the photoabsorption cross sections. The conformity of the positions of calculated peaks of giant autoionization resonances with experimental data is substantially improved by taking into account additionally the correlation electron–electron interaction based on the model of the dynamic polarization potential.

  15. The effects of exogenous catalase on broad-spectrum near-UV (300-400nm) treated Escherichia coli cells

    International Nuclear Information System (INIS)

    Sammartano, L.J.; Tuveson, R.W.

    1984-01-01

    Catalase incorporated into plating medium protects against inactivation and mutagenesis by broad-spectrum near-ultraviolet wavelength (300-400nm) (NUV) radiation in strains of Escherichia coli. Plating medium containing catalase does not provide protection against inactivation by wavelengths in the FUV region. Catalase added to the cell suspension during or added immediately after NUV exposure also protects against inactivation. The protection provided by catalase suggests a possible role for hydrogen peroxide in the processes of inactivation and mutagenesis by broad-spectrum NUV. (author)

  16. Photoabsorption and Compton scattering in ionization of helium at high photon energies

    International Nuclear Information System (INIS)

    Andersson, L.R.; Burgdoerfer, J.; Tennessee Univ., Knoxville, TN

    1993-01-01

    Production of singly and doubly charged helium ions by impact of keV photons is studied. The ratio R ph = σ ph ++ /σ ph + for photoabsorption is calculated in the photon-energy range 2--18 keV using correlated initial- and final- state wave functions. Extrapolation towards asymptotic photon energies yields R ph (ω → ∞) = 1.66% in agreement with previous predictions. Ionization due to Compton scattering, which becomes comparable to photoabsorption above ω ∼ 3 keV, is discussed

  17. Time-dependent density functional theory description of total photoabsorption cross sections

    Science.gov (United States)

    Tenorio, Bruno Nunes Cabral; Nascimento, Marco Antonio Chaer; Rocha, Alexandre Braga

    2018-02-01

    The time-dependent version of the density functional theory (TDDFT) has been used to calculate the total photoabsorption cross section of a number of molecules, namely, benzene, pyridine, furan, pyrrole, thiophene, phenol, naphthalene, and anthracene. The discrete electronic pseudo-spectra, obtained in a L2 basis set calculation were used in an analytic continuation procedure to obtain the photoabsorption cross sections. The ammonia molecule was chosen as a model system to compare the results obtained with TDDFT to those obtained with the linear response coupled cluster approach in order to make a link with our previous work and establish benchmarks.

  18. Evaluation of an economical sunlamp that emits a near solar UV power spectrum for conducting photoimmunological and sunscreen immune protection studies

    International Nuclear Information System (INIS)

    Beasley, D.G.; Roberts, L.K.; Beard, J.; Stanfield, J.W.

    1996-01-01

    Unlike FS-type UVB sunlamps, which have a significant amount of effective immunosuppressive non-solar UV energy at wavelengths below 295 nm, the immunosuppression effectiveness spectrum of UVA-340 sunlamps was nearly identical to that of a solar simulator. The purpose of this study was to evaluate this sunlamp for conducting photoimmunological and sunscreen immune protection studies. Groups of C3H mice were exposed to a range of UVA-340 sunlamp doses (0.25 kJ/m 2 to 20.0 kJ/m 2 ) to establish a dose-response curve and determine the minimum immune suppression dose (MISD) for induction of local-type suppression of contact hypersensitivity (CH). The MISD, defined as the lowest UV dose given to produce ∼ 50% suppression of the CH response in mice, was determined to be 1.0 kJ/m 2 for UVA-340 sunlamps. Immune protection tests on four marketed sunscreen lotions (sun protection factors [SPF] 4, 8, 15 and 30) were then conducted with UVA-340 sunlamps using MISD as the endpoint. The immune protection factors for these sunscreens were equivalent to the level of protection predicted by their labeled SPF. These results are similar to those we have previously obtained using a solar simulator. (author)

  19. Tunable high-power narrow-spectrum external-cavity diode laser at 675 nm as a pump source for UV generation

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Erbert, Gotz

    2011-01-01

    High-power narrow-spectrum diode laser systems based on tapered gain media in external cavity are demonstrated at 675 nm. Two 2-mm-long amplifiers are used, one with a 500-µm-long ridge-waveguide section (device A), the other with a 750-µm-long ridge-waveguide section (device B). The laser system...... of 1.0 W. The laser system B based on device B is tunable from 666 to 685 nm. As high as 1.05 W output power is obtained around 675.67 nm. The emission spectral bandwidth is less than 0.07 nm throughout the tuning range, and the beam quality factor M2 is 1.13 at an output power of 0.93 W. The laser...... system B is used as a pump source for the generation of 337.6 nm UV light by single-pass frequency doubling in a BIBO crystal. An output power of 109 µW UV light, corresponding to a conversion efficiency of 0.026%W-1 is attained....

  20. Absolute photoabsorption oscillator strengths by electron energy loss methods: the valence and S 2p and 2s inner shells of sulphur dioxide in the discrete and continuum regions (3.5-260 eV)

    International Nuclear Information System (INIS)

    Feng, R.; Cooper, G.; Burton, G.R.; Brion, C.E.; Avaldi, L.

    1999-01-01

    Absolute photoabsorption oscillator strengths (cross-sections) for the valence shell discrete and continuum regions of sulphur dioxide from 3.5 to 51 eV have been measured using high resolution (∼0.05 eV FWHM) dipole (e,e) spectroscopy. A wide-range spectrum, covering both the valence shell and the S 2p and 2s inner shells, has also been obtained from 5 to 260 eV at low resolution (∼1 eV FWHM), and this has been used to determine the absolute oscillator strength scale using valence shell TRK (i.e., S(0)) sum-rule normalization. The present measurements have been undertaken in order to investigate the recently discovered significant quantitative errors in our previously published low resolution dipole (e,e) work on sulphur dioxide (Cooper et al., Chem. Phys. 150 (1991) 237; 150 (1991) 251). These earlier measurements were also in poor agreement with other previously published direct photoabsorption measurements. We now report new absolute photoabsorption oscillator strengths using both high and low resolution dipole (e,e) spectroscopies. These new measurements cover a wider energy range and are much more consistent with the previously published direct photoabsorption measurements. The accuracy of our new measurements is confirmed by an S(-2) dipole sum-rule analysis which gives a static dipole polarizability for sulphur dioxide in excellent agreement (within 3.5%) with previously reported polarizability values. Other dipole sums S(u) (u=-1,-3 to -6,-8,-10) and logarithmic dipole sums L(u) (u=-1 to -6) are also determined from the presently reported absolute oscillator strength distributions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. Line Identification of Atomic and Ionic Spectra of Holmium in the Near-UV. Part I. Spectrum of Ho i

    Energy Technology Data Exchange (ETDEWEB)

    Al-Labady, N.; Özdalgiç, B. [Graduate School of Engineering and Sciences, Istanbul University, TR-34452 Beyazıt, Istanbul (Turkey); Er, A.; Güzelçimen, F.; Öztürk, I. K.; Başar, Gö. [Faculty of Science, Department of Physics, Istanbul University, TR-34134 Vezneciler, Istanbul (Turkey); Kröger, S. [Hochschule für Technik und Wirtschaft Berlin, Wilhelminenhofstr. 75A, D-12459 Berlin (Germany); Kruzins, A.; Tamanis, M.; Ferber, R., E-mail: ikanat@istanbul.edu.tr [Laser Centre, The University of Latvia, Rainis Boulevard 19, LV-1586 Riga (Latvia)

    2017-02-01

    The Fourier Transform spectra of a Holmium hollow cathode discharge lamp have been investigated in the UV spectral range from 25,000 up to 31,530 cm{sup −1} (317 to 400 nm). Two Ho spectra have been measured with neon and argon as buffer gases. Based on the intensity ratios from these two spectra, a distinction was made between atomic and ionic lines (ionic lines are discussed in an accompanying paper). Using the known Ho i energy levels, 71 lines could be classified as transitions of atomic Ho, 34 of which have not been published previously. Another 32 lines, which could not be classified, are listed in the literature and assigned as atomic Ho. An additional 370 spectral lines have been assigned to atomic Ho based on the signal-to-noise ratio in the two spectra measured under different discharge conditions, namely with buffer gases argon and neon, respectively. These 370 lines have not been previously listed in the literature.

  2. Solvent Dependency of the UV-Vis Spectrum of Indenoisoquinolines: Role of Keto-Oxygens as Polarity Interaction Probes

    Science.gov (United States)

    Coletta, Andrea; Castelli, Silvia; Chillemi, Giovanni; Sanna, Nico; Cushman, Mark; Pommier, Yves; Desideri, Alessandro

    2013-01-01

    Indenoisoquinolines are the most promising non-campthotecins topoisomerase IB inhibitors. We present an integrated experimental/computational investigation of the UV-Vis spectra of the IQNs parental compound (NSC314622) and two of its derivatives (NSC724998 and NSC725776) currently undergoing Phase I clinical trials. In all the three compounds a similar dependence of the relative absorption intensities at 270 nm and 290 nm on solvent polarity is found. The keto-oxygens in positions 5 and 11 of the molecular scaffold of the molecule are the principal chromophores involved in this dependence. Protic interactions on these sites are also found to give rise to absorptions at wavelength <250 nm observed in water solution, due to the stabilization of highly polarized tautomers of the molecule. These results suggest that the keto-oxygens are important polarizable groups that can act as useful interactors with the molecular receptor, providing at the same time an useful fingerprint for the monitoring of the drug binding to topoisomerase IB. PMID:24086299

  3. Effects of configuration interaction on photoabsorption spectra in the continuum

    International Nuclear Information System (INIS)

    Komninos, Yannis; Nicolaides, Cleanthes A.

    2004-01-01

    It is pointed out that the proper interpretation of a recently published experimental spectrum from the multilaser photoionization of Sr [Eichmann et al., Phys. Rev. Lett. 90, 233004 (2003)] must account for a radiative transition between two autoionizing states. The application of orthonormality selection rules and of configuration-interaction theory involving the continuous spectrum and the quasicontinuum of the upper part of Rydberg series explains quantitatively the appearance, the shape, and the variation of heights of the observed peaks of resonances

  4. Photoabsorption cross sections of methane and ethane, 1380-1600 A, at T=295 K and T=200 K

    International Nuclear Information System (INIS)

    Mount, G.H.; Moos, H.W.

    1978-01-01

    Photoabsorption cross sections of methane and ethane gas have been determined from 1380-1600 A at room and dry-ice temperatures. A small decrease in cross section was measured near the molecular absorption edge for each gas. In addition, the photoabsorption cross sections of ethane at room temperature are found to be in agreement with the measurements of Okabe and Becker rather than more recently determined values

  5. Vacancy-Rich Monolayer BiO2-x as a Highly Efficient UV, Visible, and Near-Infrared Responsive Photocatalyst.

    Science.gov (United States)

    Li, Jun; Wu, Xiaoyong; Pan, Wenfeng; Zhang, Gaoke; Chen, Hong

    2018-01-08

    Vacancy-rich layered materials with good electron-transfer property are of great interest. Herein, a full-spectrum responsive vacancy-rich monolayer BiO 2-x has been synthesized. The increased density of states at the conduction band (CB) minimum in the monolayer BiO 2-x is responsible for the enhanced photon response and photo-absorption, which were confirmed by UV/Vis-NIR diffuse reflectance spectra (DRS) and photocurrent measurements. Compared to bulk BiO 2-x , monolayer BiO 2-x has exhibited enhanced photocatalytic performance for rhodamine B and phenol removal under UV, visible, and near-infrared light (NIR) irradiation, which can be attributed to the vacancy V Bi-O ''' as confirmed by the positron annihilation spectra. The presence of V Bi-O ''' defects in monolayer BiO 2-x promoted the separation of electrons and holes. This finding provides an atomic level understanding for developing highly efficient UV, visible, and NIR light responsive photocatalysts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. K-Shell Photoabsorption Cross Sections for the Magnesium Isonuclear Sequence

    Science.gov (United States)

    Abdel-Naby, Shahin; Hasoglu, Fatih; Gorczyca, Thomas

    2011-05-01

    With the improved spectral resolution of launched X-ray telescopes, there is a demand for highly-accurate K-shell photoabsorption cross sections. Such data are needed for modeling astrophysical plasmas, interpreting the observed spectra from distant cosmic emitters, and determining the elemental abundances of the interstellar medium (ISM). Here we present new calculations for photoabsorption of the entire Mg isonuclear sequence using state-of-the-art R-matrix methods, including important spectator Auger broadening and inner-shell relaxation effects. Unlike our earlier work on carbon, oxygen, and neon ions, and the present work on multiply-ionized magnesium, the calculations for neutral Mg and singly-ionized Mg+ are complicated by additional M-shell occupancy, which leads to a larger R-matrix box and difficulties in implementing the quantum defect theoretical spectator Auger decay method for low-lying resonances. With the improved spectral resolution of launched X-ray telescopes, there is a demand for highly-accurate K-shell photoabsorption cross sections. Such data are needed for modeling astrophysical plasmas, interpreting the observed spectra from distant cosmic emitters, and determining the elemental abundances of the interstellar medium (ISM). Here we present new calculations for photoabsorption of the entire Mg isonuclear sequence using state-of-the-art R-matrix methods, including important spectator Auger broadening and inner-shell relaxation effects. Unlike our earlier work on carbon, oxygen, and neon ions, and the present work on multiply-ionized magnesium, the calculations for neutral Mg and singly-ionized Mg+ are complicated by additional M-shell occupancy, which leads to a larger R-matrix box and difficulties in implementing the quantum defect theoretical spectator Auger decay method for low-lying resonances. This work was funded in part by NASA's Astronomy Physics Research and Analysis (APRA) program.

  7. Photoabsorption Spectrum and Optically Forbidden Transitions of Krypton by Electron Impact

    Institute of Scientific and Technical Information of China (English)

    苑震生; 朱林繁; 李文斌; 成华东; 徐克尊

    2002-01-01

    A high resolution fast electron energy loss spectrometer with multi-channel energy analysis was employed. The maxima just above the threshold 4p-1(2P1/2), which is regarded as a shape resonance, was obtained at 16.3 eV. The optically forbidden excitations of 4s electron were measured for the first time, and the energy positions are 23.75 eV(4s-15s), 25.66 eV (4s-16s/4d) and 26.60 eV(4s-17s/5d).

  8. High-resolution vacuum-ultraviolet photoabsorption spectra of 1-butyne and 2-butyne

    Energy Technology Data Exchange (ETDEWEB)

    Jacovella, U. [Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich (Switzerland); Holland, D. M. P. [STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Boyé-Péronne, S.; Gans, B. [Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS and Université Paris-Sud, F-91405 Orsay (France); Oliveira, N. de; Joyeux, D.; Archer, L. E. [Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette (France); Lucchese, R. R. [Department of Chemistry, Texas A& M University, College Station, Texas 77843 (United States); Xu, H.; Pratt, S. T. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2015-07-21

    The absolute photoabsorption cross sections of 1- and 2-butyne have been recorded at high resolution by using the vacuum-ultraviolet Fourier-Transform spectrometer at the SOLEIL Synchrotron. Both spectra show more resolved structure than previously observed, especially in the case of 2-butyne. In this work, we assess the potential importance of Rydberg states with higher values of orbital angular momentum, l, than are typically observed in photoabsorption experiments from ground state molecules. We show how the character of the highest occupied molecular orbitals in 1- and 2-butyne suggests the potential importance of transitions to such high-l (l = 3 and 4) Rydberg states. Furthermore, we use theoretical calculations of the partial wave composition of the absorption cross section just above the ionization threshold and the principle of continuity of oscillator strength through an ionization threshold to support this conclusion. The new absolute photoabsorption cross sections are discussed in light of these arguments, and the results are consistent with the expectations. This type of argument should be valuable for assessing the potential importance of different Rydberg series when sufficiently accurate direct quantum chemical calculations are difficult, for example, in the n ≥ 5 manifolds of excited states of larger molecules.

  9. Absolute photoabsorption cross-sections (oscillator strengths) for hydrogen chloride, hydrogen bromide and hydrogen iodide

    International Nuclear Information System (INIS)

    Brion, C.E.; Dyck, M.; Cooper, G.

    2004-01-01

    Full text: Absolute photoabsorption cross-sections (oscillator strengths) for the free molecules HCl, HBr and HI have been measured in the valence and selected in- ner shell regions. The experimental technique used for these studies is dipole (e,e) spectroscopy [1-3] which is not affected by line saturation effects (i.e. bandwidth interactions) which can complicate direct photoabsorption methods using the Beer- Lambert law. The dipole (e,e) method is also not subject to the effects of higher order radiation. In the dipole (e,e) method relative intensities obtained in fast (3 keV) for- ward scattered electron energy loss spectra are converted to relative dipole oscillator strengths (i.e. photoabsorption spectra) using the known Bethe-Born factors for the instrument as a function of photon energy (i.e. energy loss). The target pressure is constant at 10 - 5 torr, but it is not necessary to know the absolute target density. The absolute oscillator strength scale for HCl is determined from Bethe-Born converted, wide range dipole (e,e) spectra using the Thomas-Reiche-Kuhn (TRK) sum rule. For HBr and HI the absolute oscillator strength scales have been established using the S(-2) Sum Rule and literature values of the static dipole polarizability

  10. Comets in UV

    Science.gov (United States)

    Shustov, B.; Sachkov, M.; Gómez de Castro, A. I.; Vallejo, J. C.; Kanev, E.; Dorofeeva, V.

    2018-04-01

    Comets are important "eyewitnesses" of Solar System formation and evolution. Important tests to determine the chemical composition and to study the physical processes in cometary nuclei and coma need data in the UV range of the electromagnetic spectrum. Comprehensive and complete studies require additional ground-based observations and in situ experiments. We briefly review observations of comets in the ultraviolet (UV) and discuss the prospects of UV observations of comets and exocomets with space-borne instruments. A special reference is made to the World Space Observatory-Ultraviolet (WSO-UV) project.

  11. Kinetics of the reaction of F atoms with O2 and UV spectrum of FO2 radicals in the gas phase at 295 K

    DEFF Research Database (Denmark)

    Ellermann, T.; Sehested, J.; Nielsen, O.J.

    1994-01-01

    The ultraviolet absorption spectrum of FO2 radicals and the kinetics of the reaction of F atoms with O2 have been studied in the gas phase at 295 K using pulse radiolysis combined with kinetic UV spectroscopy. At 230 nm, sigma(FO2) = (5.08 +/- 0.70) X 10(-18) cm2 molecule-1. The kinetics of the r......The ultraviolet absorption spectrum of FO2 radicals and the kinetics of the reaction of F atoms with O2 have been studied in the gas phase at 295 K using pulse radiolysis combined with kinetic UV spectroscopy. At 230 nm, sigma(FO2) = (5.08 +/- 0.70) X 10(-18) cm2 molecule-1. The kinetics...

  12. UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

    Directory of Open Access Journals (Sweden)

    Ricarda Modarressie

    2015-05-01

    Full Text Available Social aggregations occur in many different animal taxa and mainly result from non-random assortment. Investigating factors that shape and maintain the composition of social aggregations are among others a main topic for understanding ecological speciation processes. Aggregation decisions are mediated by olfactory and visual cues, which in many animals are extended into the UV part of the electromagnetic spectrum. Here, we were interested in developmental plasticity of social preferences with respect to UV radiation in aquatic organisms. Specifically, we tested whether different lighting environments with respect to UV wavelengths during early life stages influence the shoaling preference in juvenile threespine sticklebacks (Gasterosteus aculeatus. Family (full-sibling groups were split and reared under UV-lacking (UV- and UV-present (UV+ lighting conditions. Subsequent shoal choice experiments, in which test fish from both rearing conditions could simultaneously choose between a shoal seen behind a UV-blocking (UV- and a shoal seen behind a UV-transmitting (UV+ filter, revealed a significant effect of lighting condition during rearing on association preference. Test fish that had been deprived of UV spent significantly more time near the UV- shoal compared to the test fish reared under full-spectrum lighting conditions. The results are discussed with respect to plasticity of the visual system and environmental lighting conditions.

  13. The generalized nuclear contact and its application to the photoabsorption cross-section

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Ronen; Barnea, Nir [The Hebrew University, The Racah Institute of Physics, Jerusalem (Israel); Bazak, Betzalel [The Hebrew University, The Racah Institute of Physics, Jerusalem (Israel); Universite Paris-Sud, Institut de Physique Nucleaire, CNRS/IN2P3, Orsay (France)

    2016-04-15

    Using the zero-range model, it was demonstrated recently that Levinger's quasi-deuteron model can be utilized to extract the nuclear neutron-proton contact. Going beyond the zero-range approximation and considering the full nuclear contact formalism, we rederive here the quasi-deuteron model for the nuclear photoabsorption cross-section and utilize it to establish relations and constraints for the general contact matrix. We also define and demonstrate the importance of the diagonalized nuclear contacts, which can be also relevant to further applications of the nuclear contacts. (orig.)

  14. A Fourier transform spectrometer without a beam splitter for the vacuum ultraviolet range: From the optical design to the first UV spectrum.

    Science.gov (United States)

    de Oliveira, N; Joyeux, D; Phalippou, D; Rodier, J C; Polack, F; Vervloet, M; Nahon, L

    2009-04-01

    -based synchrotron radiation beamline (Super-ACO facility, LURE, Orsay, France). A high resolution spectrum of O2 (the Schumann-Runge absorption bands, 185-200 nm) was computed from recorded interferograms using the beamline monochromator at the zeroth order to feed the instrument with an 11% relative bandwidth "white" beam (2003). These UV measurements are very close to those found in the literature, showing nominal performances of the FT spectrometer that should translate into an unprecedented resolving power at shortest VUV wavelengths. A recent upgrade (2007) and future developments will be discussed in light of the current installation of the upgraded FT spectrometer as a permanent endstation for ultrahigh resolution absorption spectrometry on the VUV beamline DESIRS at SOLEIL, the new French third generation synchrotron facility.

  15. Photoabsorption spectra of potassium and rubidium near the K-edge

    International Nuclear Information System (INIS)

    Azuma, Y.; Berry, H.G.; Cowan, P.L.

    1995-01-01

    We have used a high-temperature circulating heat-pipe absorption cell together with monochromatized X-ray beams at the X24A and X23A2 beam lines at the NSLS to obtain photoabsorption spectra of potassium and rubidium at their K- and KM-edges. The photon-energy ranges lay near 3600 eV and 15200 eV, respectively. We have also obtained first measurements of the LII and LIII edges in cesium. Although the K-edge photoabsorptions of the rare gases have been studied, there is little previous work on other atomic vapors. Most of the edges and resonance peaks that we observed have now been identified using Dirac Hartree-Fock calculations. As a check, we have compared these results with those obtained previously in closed-shell rare-gas absorption spectra. The absolute energies were obtained through a calibration of the X24A systems using measurements of several metal L-edges in the 3200-5000 eV energy range. We found that the 4p resonance in potassium is significantly enhanced compared with the corresponding situation in argon. Likewise, the 5p resonance in krypton is unresolved from the background ionization cross section, whereas it is well resolved in rubidium. As suggested by Amusia, these enhancements may be due to the enhanced potential seen in the excited state of the alkali systems as a result of the presence of an s-electron which reduces the nuclear shielding

  16. Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV

    Energy Technology Data Exchange (ETDEWEB)

    Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferreira da Silva, F.; Almeida, D. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Hoshino, M.; Tanaka, H. [Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Mogi, D. [Development and Marketing Department, New Products Development Division, Kanto Denka, Kogyo Co., Ltd., Chiyoda-ku, Tokyo 101-0063 (Japan); Tanioka, T. [Shibukawa Development Research Laboratory, New Products Development Division, Kanto Denka Kogyo Co., Ltd., Shibukawa City, Gunma 377-8513 (Japan); Mason, N. J. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, allée de la Chimie 3, B-4000 Liège 1 (Belgium)

    2015-02-14

    The electronic state spectroscopy of carbonyl sulphide, COS, has been investigated using high resolution vacuum ultraviolet photoabsorption spectroscopy and electron energy loss spectroscopy in the energy range of 4.0–10.8 eV. The spectrum reveals several new features not previously reported in the literature. Vibronic structure has been observed, notably in the low energy absorption dipole forbidden band assigned to the (4π←3π) ({sup 1}Δ←{sup 1}Σ{sup +}) transition, with a new weak transition assigned to ({sup 1}Σ{sup −}←{sup 1}Σ{sup +}) reported here for the first time. The absolute optical oscillator strengths are determined for ground state to {sup 1}Σ{sup +} and {sup 1}Π transitions. Based on our recent measurements of differential cross sections for the optically allowed ({sup 1}Σ{sup +} and {sup 1}Π) transitions of COS by electron impact, the optical oscillator strength f{sub 0} value and integral cross sections (ICSs) are derived by applying a generalized oscillator strength analysis. Subsequently, ICSs predicted by the scaling are confirmed down to 60 eV in the intermediate energy region. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of carbonyl sulphide in the upper stratosphere (20–50 km)

  17. Total photoabsorption cross section on nuclei measured in energy range 0.5-2.6 GeV

    International Nuclear Information System (INIS)

    Mirazita, M.

    1998-03-01

    The total photoabsorption cross section on several nuclei has been measured in the energy range 0.5 - 2.6 GeV. Nuclear data show a significant reduction of the absorption strength with respect to the free nucleon case suggesting a shadowing effect at low energies

  18. Total nuclear photoabsorption cross section in the range 0.2 - 1.0 GeV for nuclei throughout the periodic table

    International Nuclear Information System (INIS)

    Terranova, M.L.; Tavares, O.A.P.

    1993-01-01

    An analysis of the total photoabsorption cross section for nuclei ranging from 4 He up to 238 U has been performed in the energy range 0.2-1.0 GeV. Mean total photoabsorption cross sections have been obtained by summing up the contributions from partial photo reactions, and found to follow an A l -dependence in the 0.2-1.0 GeV range. A review of the available total photoabsorption cross section data is also presented. Comparisons have been made with cross section values calculated by considering both the quasi-deuteron and π-meson photoproduction mechanism of primary nuclear photo interaction. (author)

  19. Total nuclear photoabsorption cross section in the range 0.2-1.0 GeV for nuclei throughout the periodic table

    International Nuclear Information System (INIS)

    Terranova, M.L.; Tavares, O.A.P.

    1994-01-01

    An analysis of the total photoabsorption cross section for nuclei ranging from 4 He up to 238 U has been performed in the energy range 0.2-1.0 GeV. Mean total photoabsorption cross sections have been obtained by summing up the contributions from partial photoreactions, and found to follow an A 1 -dependence in the 0.2-1.0 GeV range. A review of the available total photoabsorption cross section data is also presented. Comparisons have been made with cross section values calculated by considering both the quasi-deuteron and π-meson photoproduction mechanism of primary nuclear photointeraction. (orig.)

  20. Solar-Iss a New Solar Reference Spectrum Covering the Far UV to the Infrared (165 to 3088 Nm) Based on Reanalyzed Solar/solspec Cycle 24 Observations

    Science.gov (United States)

    Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Bolsée, D.; Pereira, N.; Sluse, D.; Cessateur, G.

    2017-12-01

    Since April 5, 2008 and until February 15, 2017, the SOLSPEC (SOLar SPECtrometer) spectro-radiometer of the SOLAR facility on the International Space Station performed accurate measurements of Solar Spectral Irradiance (SSI) from the far ultraviolet to the infrared (165 nm to 3088 nm). These measurements, unique by their large spectral coverage and long time range, are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry), noticeably through the "top-down" mechanism amplifying ultraviolet (UV) solar forcing effects on the climate (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and troposphere regions). SOLAR/SOLSPEC, with almost 9 years of observations covering the essential of the unusual solar cycle 24 from minimum in 2008 to maximum, allowed to establish new reference solar spectra from UV to IR (165 to 3088 nm) at minimum (beginning of mission) and maximum of activity. The complete reanalysis was possible thanks to revised engineering corrections, improved calibrations and advanced procedures to account for thermal, aging and pointing corrections. The high quality and sensitivity of SOLSPEC data allow to follow temporal variability in UV but also in visible along the cycle. Uncertainties on these measurements are evaluated and results, absolute reference spectra and variability, are compared with other measurements (WHI, ATLAS-3, SCIAMACHY, SORCE/SOLSTICE, SORCE/SIM) and models (SATIRE-S, NRLSSI, NESSY)

  1. Photoabsorption of green and red fluorescent protein chromophore anions in vacuo.

    Science.gov (United States)

    Wan, Songbo; Liu, Shasha; Zhao, Guangjiu; Chen, Maodu; Han, Keli; Sun, Mengtao

    2007-09-01

    Photoabsorption properties of green and red fluorescent protein chromophore anions in vacuo were investigated theoretically, based on the experimental results in gas phase [Phys. Rev. Lett. 2001, 87, 228102; Phys. Rev. Lett. 2003, 90, 118103]. Their calculated transition energies in absorption with TD-DFT and ZINDO methods are directly compared to the experimental reports in gas phase, and the calculations with ZINDO method can correctly reproduce the absorption spectra. The orientation and strength of their transition dipole moments were revealed with transition density. We also showed the orientation and result of their intramolecular charge transfer with transition difference density. The calculated results show that with the increase of the extended conjugated system, the orientation of transition dipole moments and the orientation of charge transfer can be reversed. They are the linear responds with the external electric fields. These theoretical results reveal the insight understanding of the photoinduced dynamics of green and red fluorescent protein chromophore anions and cations in vacuo.

  2. L-shell photoabsorption spectroscopy for solid metals: Ti, V, Cr, Fe, Ni, Cu

    International Nuclear Information System (INIS)

    Del Grande, N.K.

    1989-01-01

    Synchrotron radiation measurements of near-threshold and broad-range (400--1500 eV) absolute photoabsorption cross sections were made for five transition metals with ±10% overall uncertainties. Fine structure details of 2p-3d autoionizing resonances are shown with better than 1.0 eV resolution for solid metals: Ti, V, Cr, Fe, Ni, and Cu. Fine structure similar to what we measured can be produced using a multi-configuration Dirac Fock (MCDF) model if a statistical distribution is assumed for the initial atomic states. Calculations were performed in intermediate coupling with configuration interactions by Mau H. Chen. The results are compared with other experimental work and theoretical methodologies. 18 refs., 7 figs

  3. Electron-He+ P-wave elastic scattering and photoabsorption in two-electron systems

    International Nuclear Information System (INIS)

    Bhatia, A. K.

    2006-01-01

    In a previous paper [A. K. Bhatia, Phys. Rev. A 69, 032714 (2004)], electron-hydrogen P-wave scattering phase shifts were calculated using the optical potential approach based on the Feshbach projection operator formalism. This method is now extended to the singlet and triplet electron-He + P-wave scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 220 terms. Results are rigorous lower bounds to the exact phase shifts, and they are compared to phase shifts obtained from the method of polarized orbitals and close-coupling calculations. The continuum functions calculated here are used to calculate photoabsorption cross sections. Photoionization cross sections of He and photodetachment cross sections of H - are calculated in the elastic region--i.e., leaving He + and H in their respective ground states--and compared with previous calculations. Radiative attachment rates are also calculated

  4. Characterization of combustion chamber products by core-level photoabsorption spectroscopy

    International Nuclear Information System (INIS)

    Kellar, S.A.; Huff, W.R.A.; Moler, E.J.

    1997-01-01

    The lubricating performance of motor oil is adversely affected by the carbon soot contamination that is a natural by-product of the combustion process. Particularly in diesel engines, open-quote blow-by close-quote is a problem that greatly decreases the longevity of the engine-lubricating oil. Motor oil manufacturers spend considerable resources developing new oil formulations that counteract the adverse affects of this combustion soot. At present, the only effective way to test new formulations is in a working engine. This process is obviously expensive and not especially efficient. In this ongoing work in collaboration with Chevron Research and Technology, the authors goal is to find a form of carbon that chemically resembles the soot created by the open-quote blow-by close-quote in a diesel engine. The chemically correct soot substitute can be used in bench tests to replace the expensive full motor testing for new formulations. The final testing would still be done in the test motors but only with promising candidates. To these ends, Near Edge X-ray Adsorption spectroscopy Extended Fine Structure (NEXAFS) is an attractive technique in that it has chemical specificity through the core-level binding energy and because it probes the chemically important unoccupied molecular orbitals of the material. Core-level photoabsorption has been used to characterize the empty electronic states of a wide variety of materials. Specifically, the near-edge region of the photoabsorption process has been used to determine the relative quantity of sp 2 and sp 3 bonding in carbon films. The samples were fine grained powders pressed into pellets. The C(1s) absorption spectra were collected from each sample by measuring the total electron yield from the sample as a function of photon energy. The absorption intensity was normalized to the incoming photon flux by measuring the photoyield from a fine gold mesh

  5. uv photobiology: DNA damage and repair

    International Nuclear Information System (INIS)

    Sutherland, B.M.

    1978-01-01

    The following topics are discussed: targets that determine the fate of the cell when uv light interacts with a cell; comparison of action spectrum for a given biological effect with the absorption spectrum of different biological macromolecules; biological effects of damage to DNA; measurement of mutations; chemical damage to DNA; photoreactivation; role of pyrimidine dimers in induction of skin cancer by uv

  6. Three-dimensional Ag2O/Bi5O7I p-n heterojunction photocatalyst harnessing UV-vis-NIR broad spectrum for photodegradation of organic pollutants.

    Science.gov (United States)

    Chen, Yannan; Zhu, Gangqiang; Hojamberdiev, Mirabbos; Gao, Jianzhi; Zhu, Runliang; Wang, Chenghui; Wei, Xiumei; Liu, Peng

    2018-02-15

    Ag 2 O nanoparticles-loaded Bi 5 O 7 I microspheres forming a three dimensional Ag 2 O/Bi 5 O 7 I p-n heterojunction photocatalyst with wide-spectrum response were synthesized in this study. The results of transmission electron microscopy observations revealed that the Ag 2 O nanoparticles with the diameter of ca. 10-20nm were distributed on the surfaces of Bi 5 O 7 I nanosheets. The as-synthesized Ag 2 O/Bi 5 O 7 I exhibited an excellent wide-spectrum response to wavelengths ranging from ultraviolet (UV) to near-infrared (NIR), indicating its potential for effective utilization of solar energy. Compared with pure Bi 5 O 7 I, the Ag 2 O/Bi 5 O 7 I composite also demonstrated excellent photocatalytic activity for the degradation of Bisphenol A and phenol in aqueous solution under visible LED light irradiation. Among samples, the 20% Ag 2 O/Bi 5 O 7 I composite photocatalyst showed the highest photocatalytic activity for the degradation of Bisphenol A and phenol in aqueous solution. In addition, the 20% Ag 2 O/Bi 5 O 7 I composite also exhibited a photocatalytic activity for the degradation of Bisphenol A under NIR light irradiation. The improved photocatalytic activity is attributed to the formation of a p-n heterojunction between Ag 2 O and Bi 5 O 7 I, allowing the efficient utilization of solar energy (from UV to NIR) and high separation efficiency of photogenerated electron-hole pairs. The present work is desirable to explore a possible avenue for the full utilization of solar energy. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A multifrequency virtual spectrometer for complex bio-organic systems: vibronic and environmental effects on the UV/Vis spectrum of chlorophyll a.

    Science.gov (United States)

    Barone, Vincenzo; Biczysko, Malgorzata; Borkowska-Panek, Monika; Bloino, Julien

    2014-10-20

    The subtle interplay of several different effects means that the interpretation and analysis of experimental spectra in terms of structural and dynamic characteristics is a challenging task. In this context, theoretical studies can be helpful, and as such, computational spectroscopy is rapidly evolving from a highly specialized research field toward a versatile and widespread tool. However, in the case of electronic spectra (e.g. UV/Vis, circular dichroism, photoelectron, and X-ray spectra), the most commonly used methods still rely on the computation of vertical excitation energies, which are further convoluted to simulate line shapes. Such treatment completely neglects the influence of nuclear motions, despite the well-recognized notion that a proper account of vibronic effects is often mandatory to correctly interpret experimental findings. Development and validation of improved models rooted into density functional theory (DFT) and its time-dependent extension (TD-DFT) is of course instrumental for the optimal balance between reliability and favorable scaling with the number of electrons. However, the implementation of easy-to-use and effective procedures to simulate vibrationally resolved electronic spectra, and their availability to a wide community of users, is at least equally important for reliable simulations of spectral line shapes for compounds of biological and technological interest. Here, such an approach has been applied to the study of the UV/Vis spectra of chlorophyll a. The results show that properly tailored approaches are feasible for state-of-the-art computational spectroscopy studies, and allow, with affordable computational resources, vibrational and environmental effects on the spectral line shapes to be taken into account for large systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. JUPITER AS AN EXOPLANET: UV TO NIR TRANSMISSION SPECTRUM REVEALS HAZES, A Na LAYER, AND POSSIBLY STRATOSPHERIC H{sub 2}O-ICE CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Montañés-Rodríguez, Pilar; González-Merino, B.; Pallé, E. [Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, E-38200 La Laguna (Spain); López-Puertas, Manuel [Departamento de Astrofísica, Universidad de La Laguna, Av., Astrofísico Francisco Sánchez, s/n, E-38206 La Laguna (Spain); García-Melendo, E., E-mail: pmr@iac.es [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, E-18080 Granada (Spain)

    2015-03-01

    Currently, the analysis of transmission spectra is the most successful technique to probe the chemical composition of exoplanet atmospheres. However, the accuracy of these measurements is constrained by observational limitations and the diversity of possible atmospheric compositions. Here, we show the UV–VIS–IR transmission spectrum of Jupiter as if it were a transiting exoplanet, obtained by observing one of its satellites, Ganymede, while passing through Jupiter’s shadow, i.e., during a solar eclipse from Ganymede. The spectrum shows strong extinction due to the presence of clouds (aerosols) and haze in the atmosphere and strong absorption features from CH{sub 4}. More interestingly, the comparison with radiative transfer models reveals a spectral signature, which we attribute here to a Jupiter stratospheric layer of crystalline H{sub 2}O ice. The atomic transitions of Na are also present. These results are relevant for the modeling and interpretation of giant transiting exoplanets. They also open a new technique to explore the atmospheric composition of the upper layers of Jupiter’s atmosphere.

  9. Doping effect on photoabsorption and charge-separation dynamics in light-harvesting organic molecule

    Directory of Open Access Journals (Sweden)

    Satoshi Ohmura

    2016-01-01

    Full Text Available Using ab-initio theoretical methods, we demonstrate possible enhancement of photo-conversion efficiency of an organic solar cell via intentional doping in molecular graphene-fullerene heterojunction [the hexabenzocoronene (HBC-triethylene glycol (TEG–C60 molecule]. Photoabsorption analysis indicates oxygen substitution into HBC leads to an extension of the spectra up to an infrared regime. A quantum-mechanical molecular dynamics simulation incorporating nonadiabatic electronic transitions reveals that a dissociated charge state (D+ and A- in the O-doped system is more stable than the pristine case due to the presence of an effective barrier by the TEG HOMO/LUMO level. We also find that oxygen doping in HBC enhances the intermolecular carrier mobility after charge separation. On the other hand, the pristine molecule undergoes rapid recombination between donor and acceptor charges at the interface. These analyses suggest that the graphene oxidation opens a new window in the application of organic super-molecules to solar cells.

  10. Photoabsorption modulation in GaAs: Ga1-xInx as strained-layer superlattices

    International Nuclear Information System (INIS)

    Sella, I.; Watkins, D.E.; Laurich, B.K.; Smith, D.L.; Subbanna, S.; Kroemer, H.

    1990-01-01

    Photoabsorption modulation measurements have been made on Ga 1 -x In x As -- GaAs strained-layer superlattices using two approaches: In the first the modulating beam and the test beam have the same wavelength (near the exciton resonance). In the second, the modulation wavelength is much shorter than the test beam wavelength. A dramatic difference is observed in the modulated transmission spectra near the excitonic level for the two modulating wavelengths. The difference in behavior can be explained by screening of the residual surface electric field, which only occurs for the high photon energy modulating beam. This beam excites carriers that are free to drift in the surface field before they are captured in the quantum wells. Carriers excited by the low photon energy modulation beam are created in the wells and can not effectively screen the surface field. We describe a model which explains the nonlinear intensity saturation profile and qualitatively describes the spectral line shape. 4 refs., 4 figs

  11. Edge profiles in K shell photoabsorption spectra of gaseous hydrides of 3p elements and homologues

    Science.gov (United States)

    Hauko, R.; Gomilšek, J. Padežnik; Kodre, A.; Arčon, I.; Aquilanti, G.

    2017-10-01

    Photoabsorption spectra of gaseous hydrides of 3p elements (PH3, H2S, HCl) are measured in the energy region of photoexcitations pertaining to K edge. The analysis of the edge profile is extended to hydrides of 4p series (GeH4, AsH3, H2Se, HBr) from an earlier experiment, and to published spectra of 2p hydrides (CH4, NH3, H2O, HF) and noble gases Ar, Kr and Ne and SiH4. The edge profiles are modelled with a linear combination of lorentzian components, describing excitations to individual bound states and to continuum. Transition energies and probabilities are also calculated in the non-relativistic molecular model of the ORCA code, in good agreement with the experiment. Edge profiles in the heavier homologues are closely similar, the symmetry of the molecule governs the transitions to the lowest unoccupied orbitals. In 2p series the effect of the strong nuclear potential prevails. Transitions to higher, atomic-like levels remain very much the same as in free atoms.

  12. Coherent control of photoabsorption processes and calculation of nonlinear optical processes. Final technical report

    International Nuclear Information System (INIS)

    Lambropoulos, P.

    1998-01-01

    The work on the grant for the entire period of its duration concentrated on two different but related areas, namely coherent control of photoabsorption processes and the calculation of non linear optical processes with short wavelength radiation. On the first topic, the work dealt with the problem of controlling the population transfer from one to another bound state of a system in a route that passes through a continuum. This question is most important in the context of transferring populations between vibrational states of a molecule through a sequence of two pulses taking the system via the dissociation continuum. On the second topic, their work was motivated by the availability of XUV and soft X-ray coherent radiation sources obtained through high order harmonic generation. In addition, a few other techniques based on schemes of photo-pumped X-ray lasers promise to provide in the near-future similarly coherent sources. It is thus important to have an assessment of the possibility of extending non-linear optical processes to this range of wavelengths. This means assessing the relevant magnitude of the susceptibilities for third harmonic generation, stimulated Raman scattering, two-photon absorption, etc

  13. Doping effect on photoabsorption and charge-separation dynamics in light-harvesting organic molecule

    Energy Technology Data Exchange (ETDEWEB)

    Ohmura, Satoshi, E-mail: s.ohmura.m4@cc.it-hiroshima.ac.jp [Research Center for Condensed Matter Physics, Department of Civil Engineering and Urban Design, Hiroshima Institute of Technology, Hiroshima 731-5193 (Japan); Tsuruta, Kenji [Department of Electrical and Electronic Engineering, Okayama University, Okayama 700-8530 (Japan); Shimojo, Fuyuki [Department of Physics, Kumamoto University, Kumamoto 860-8555 Japan (Japan); Nakano, Aiichiro [Collaboratory for Advanced Computing and Simulations, Department of Computer Science, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Biological Sciences, University of Southern California, CA90089-024 (United States)

    2016-01-15

    Using ab-initio theoretical methods, we demonstrate possible enhancement of photo-conversion efficiency of an organic solar cell via intentional doping in molecular graphene-fullerene heterojunction [the hexabenzocoronene (HBC)-triethylene glycol (TEG)–C{sub 60} molecule]. Photoabsorption analysis indicates oxygen substitution into HBC leads to an extension of the spectra up to an infrared regime. A quantum-mechanical molecular dynamics simulation incorporating nonadiabatic electronic transitions reveals that a dissociated charge state (D{sup +} and A{sup -}) in the O-doped system is more stable than the pristine case due to the presence of an effective barrier by the TEG HOMO/LUMO level. We also find that oxygen doping in HBC enhances the intermolecular carrier mobility after charge separation. On the other hand, the pristine molecule undergoes rapid recombination between donor and acceptor charges at the interface. These analyses suggest that the graphene oxidation opens a new window in the application of organic super-molecules to solar cells.

  14. On the continuous spectrum electromagnetic radiation in electron-fullerene collision

    International Nuclear Information System (INIS)

    Amusia, M.Y.

    1995-01-01

    It is demonstrated that the electromagnetic radiation spectrum in electron-fullerene collisions is dominated by a huge maximum of multielectron nature, similar to that already predicted and observed in photoabsorption. Due to coherence, the intensity of this radiation is much stronger than the sum of the intensities of isolated atoms. Experimental detection of such radiation would be of great importance for understanding the mechanism of its formation and for investigating fullerene structures. A paper describing these results was published

  15. Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine

    Science.gov (United States)

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

    2014-10-01

    The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N-H...O=C, type II by a strong O-H...N hydrogen bond, type III by weak N-H...O-H hydrogen bonds, and type IV by a C=O...H-C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O-H...N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm-1, respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG undergoes facile photofragmentation

  16. Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine

    International Nuclear Information System (INIS)

    Borba, Ana; Fausto, Rui; Gómez-Zavaglia, Andrea

    2014-01-01

    The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N–H···O=C, type II by a strong O–H···N hydrogen bond, type III by weak N–H···O–H hydrogen bonds, and type IV by a C=O···H–C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O–H···N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N 2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm −1 , respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG

  17. Evolution of L -shell photoabsorption of the molecular-ion series Si Hn + (n =1 ,2 ,3 ): Experimental and theoretical studies

    Science.gov (United States)

    Kennedy, E. T.; Mosnier, J.-P.; van Kampen, P.; Bizau, J.-M.; Cubaynes, D.; Guilbaud, S.; Carniato, S.; Puglisi, A.; Sisourat, N.

    2018-04-01

    We report on complementary laboratory and theoretical investigations of the 2 p photoexcitation cross sections for the molecular-ion series Si Hn + (n =1 ,2 ,3 ) near the L -shell threshold. The experiments used an electron cyclotron resonance (ECR) plasma molecular-ion source coupled with monochromatized synchrotron radiation in a merged-beam configuration. For all three molecular ions, the S i2 + decay channel appeared dominant, suggesting similar electronic and nuclear relaxation patterns involving resonant Auger and dissociation processes, respectively. The total yields of the S i2 + products were recorded and put on absolute cross-section scales by comparison with the spectrum of the S i+ parent atomic ion. Interpretation of the experimental spectra ensued from a comparison with total photoabsorption cross-sectional profiles calculated using ab initio configuration interaction theoretical methods inclusive of vibrational dynamics and contributions from inner-shell excitations in both ground and valence-excited electronic states. The spectra, while broadly similar for all three molecular ions, moved towards lower energies as the number of screening hydrogen atoms increased from one to three. They featured a wide and shallow region below ˜107 eV due to 2 p →σ* transitions to dissociative states, and intense and broadened peaks in the ˜107 -113 -eV region merging into sharp Rydberg series due to 2 p →n δ ,n π transitions converging on the LII ,III limits above ˜113 eV . This overall spectral shape is broadly replicated by theory in each case, but the level of agreement does not extend to individual resonance structures. In addition to the fundamental interest, the work should also prove useful for the understanding and modeling of astronomical and laboratory plasma sources where silicon hydride molecular species play significant roles.

  18. Polychromatic light (480-3400nm) similar to the terrestrial solar spectrum without its UV component in post-surgical immunorehabilitation of breast cancer patients.

    Science.gov (United States)

    Zhevago, Natalia A; Zimin, Alexander A; Glazanova, Tatyana V; Davydova, Natalia I; Bychkova, Natalia V; Chubukina, Zhanna V; Buinyakova, Anna I; Ballyuzek, Marina F; Samoilova, Kira A

    2017-01-01

    To this day, two methods of phototherapy (PT) have been successfully used in post-surgical immunorehabilitation of patients with breast cancer (BC): intravenous laser irradiation of the patients' blood and reinfusion of lympholeukosuspension of BC patients after single irradiation with HeNe laser. The objective of this pilot experimental study was to verify the effectiveness of the percutaneous use of polychromatic visible light combined with polychromatic infrared (pVIS+pIR) radiation similar to the major components of natural solar spectrum in post-surgical management of BC patients. Patients with BC (adenocarcinoma) of I-II stages, n=19 who had undergone mastectomy, were divided into 2 groups. The control group of patients (n=8) underwent a conventional course of post-surgical rehabilitation and sham irradiation. Patients of the PT group (n=11) additionally received 7days of daily treatment with polychromatic light on the sacral area, D=15cm. The PT course began on the day after mastectomy (Bioptron-2 device; Switzerland, 480-3400nm, 95% polarization, 40mW/cm 2 , 24J/cm 2 ). Mastectomy produced many changes in cellular and humoral immunity, which was recorded on the 1st and 8th post-surgical days. The PT course resulted in a faster normalization of post-surgical leukocytosis and activation of cytotoxic CD8 + T-lymphocytes (Lym), reduced the elevated concentration in blood of immune complexes and in parallel promoted cytotoxic activity of CD16 + /CD56 + NK-cells. The PT up-regulated the number of NK-cells in patients with its decrease on the 1st post-surgical day and prevented the decrease in the amount of monocytes, CD19 + B-Lym, CD3 + T-Lym, CD4 + T-helpers, activated CD3 + /HLADR + T-Lym, and the decrease of the phagocytotic capability of neutrophils. PT blocked the down-regulation of the IgM, IgA concentration and abnormally sharp increase of the proinflammatory cytokine IFN-γ content. Therefore, a 7-day course with polychromatic light prevented the

  19. Interpretation of the photoelectron, ultraviolet, and vacuum ultraviolet photoabsorption spectra of bromobenzene by ab initio configuration interaction and DFT computations

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Michael H., E-mail: m.h.palmer@ed.ac.uk; Ridley, Trevor, E-mail: t.ridley@ed.ac.uk, E-mail: vronning@phys.au.dk, E-mail: nykj@phys.au.dk, E-mail: marcello.coreno@elettra.eu, E-mail: desimone@iom.cnr.it, E-mail: malgorzata.biczysko@sns.it, E-mail: kipeters@wsu.edu [School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland (United Kingdom); Hoffmann, Søren Vrønning, E-mail: t.ridley@ed.ac.uk, E-mail: vronning@phys.au.dk, E-mail: nykj@phys.au.dk, E-mail: marcello.coreno@elettra.eu, E-mail: desimone@iom.cnr.it, E-mail: malgorzata.biczysko@sns.it, E-mail: kipeters@wsu.edu; Jones, Nykola C., E-mail: t.ridley@ed.ac.uk, E-mail: vronning@phys.au.dk, E-mail: nykj@phys.au.dk, E-mail: marcello.coreno@elettra.eu, E-mail: desimone@iom.cnr.it, E-mail: malgorzata.biczysko@sns.it, E-mail: kipeters@wsu.edu [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Coreno, Marcello, E-mail: t.ridley@ed.ac.uk, E-mail: vronning@phys.au.dk, E-mail: nykj@phys.au.dk, E-mail: marcello.coreno@elettra.eu, E-mail: desimone@iom.cnr.it, E-mail: malgorzata.biczysko@sns.it, E-mail: kipeters@wsu.edu [CNR-IMIP, Montelibretti, c/o Laboratorio Elettra, Trieste (Italy); Simone, Monica de, E-mail: t.ridley@ed.ac.uk, E-mail: vronning@phys.au.dk, E-mail: nykj@phys.au.dk, E-mail: marcello.coreno@elettra.eu, E-mail: desimone@iom.cnr.it, E-mail: malgorzata.biczysko@sns.it, E-mail: kipeters@wsu.edu [CNR-IOM Laboratorio TASC, Trieste (Italy); Grazioli, Cesare [CNR-IOM Laboratorio TASC, Trieste (Italy); Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste (Italy); Zhang, Teng [Department of Physics and Astronomy, University of Uppsala, Uppsala (Sweden); and others

    2015-10-28

    New photoelectron, ultraviolet (UV), and vacuum UV (VUV) spectra have been obtained for bromobenzene by synchrotron study with higher sensitivity and resolution than previous work. This, together with use of ab initio calculations with both configuration interaction and time dependent density functional theoretical methods, has led to major advances in interpretation. The VUV spectrum has led to identification of a considerable number of Rydberg states for the first time. The Franck-Condon (FC) analyses including both hot and cold bands lead to identification of the vibrational structure of both ionic and electronically excited states including two Rydberg states. The UV onset has been interpreted in some detail, and an interpretation based on the superposition of FC and Herzberg-Teller contributions has been performed. In a similar way, the 6 eV absorption band which is poorly resolved is analysed in terms of the presence of two ππ* states of {sup 1}A{sub 1} (higher oscillator strength) and {sup 1}B{sub 2} (lower oscillator strength) symmetries, respectively. The detailed analysis of the vibrational structure of the 2{sup 2}B{sub 1} ionic state is particularly challenging, and the best interpretation is based on equation-of-motion-coupled cluster with singles and doubles computations. A number of equilibrium structures of the ionic and singlet excited states show that the molecular structure is less subject to variation than corresponding studies for iodobenzene. The equilibrium structures of the 3b{sub 1}3s and 6b{sub 2}3s (valence shell numbering) Rydberg states have been obtained and compared with the corresponding ionic limit structures.

  20. Ozone layer - climate change interactions. Influence on UV levels and UV related effects

    NARCIS (Netherlands)

    Kelfkens G; Bregman A; de Gruijl FR; van der Leun JC; Piquet A; van Oijen T; Gieskes WWC; van Loveren H; Velders GJM; Martens P; Slaper H; NOP; LPI; LLO

    2002-01-01

    Ozone in the atmosphere serves as a partially protective filter against the most harmful part of the solar UV-spectrum. Decreases in ozone lead to increases in ambient UV with a wide variety of adverse effects on human health, aquatic and terrestrial ecosystems and food chains. Human health

  1. EFFECTS OF NITROGEN PHOTOABSORPTION CROSS SECTION RESOLUTION ON MINOR SPECIES VERTICAL PROFILES IN TITAN’S UPPER ATMOSPHERE

    International Nuclear Information System (INIS)

    Luspay-Kuti, A.; Mandt, K. E.; Greathouse, T. K.; Plessis, S.

    2015-01-01

    The significant variations in both measured and modeled densities of minor species in Titan’s atmosphere call for the evaluation of possible influencing factors in photochemical modeling. The effect of nitrogen photoabsorption cross section selection on the modeled vertical profiles of minor species is analyzed here, with particular focus on C 2 H 6 and HCN. Our results show a clear impact of cross sections used on all neutral and ion species studied. Affected species include neutrals and ions that are not primary photochemical products, including species that do not even contain nitrogen. The results indicate that photochemical models that employ low-resolution cross sections may significantly miscalculate the vertical profiles of minor species. Such differences are expected to have important implications for Titan’s overall atmospheric structure and chemistry

  2. Density functional study of photoabsorption in metallic clusters using an exchange-correlation potential with correct long-range behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Torres, M.B. [Dpto. de Matematicas y Computacion, Universidad de Burgos, Burgos (Spain); Balbas, L.C. [Dpto. de Fisica Teorica, Universidad de Valladolid, Valladolid (Spain)

    2002-06-17

    The atomic exchange-correlation (xc) potential with the correct -1/r asymptotic behaviour constructed by Parr and Ghosh (Parr R G and Ghosh S K 1995 Phys. Rev. A 51 3564) is adapted here to study, within time density functional theory, the linear response to external fields of (i) neutral and charged sodium clusters, and (ii) doped clusters of the type Na{sub n}Pb (n=4, 6, 16). The resulting photoabsorption cross sections are compared to experimental results, when available, and to results from previous calculations using local and non-local xc functionals. The calculated static polarizabilities and plasmon frequencies are closer to the experimental values than previous results. (author)

  3. EFFECTS OF NITROGEN PHOTOABSORPTION CROSS SECTION RESOLUTION ON MINOR SPECIES VERTICAL PROFILES IN TITAN’S UPPER ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Luspay-Kuti, A.; Mandt, K. E.; Greathouse, T. K. [Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 (United States); Plessis, S., E-mail: aluspaykuti@swri.edu [ICES, The University of Texas at Austin, 201 East 24th Street, Austin, TX 78712 (United States)

    2015-03-01

    The significant variations in both measured and modeled densities of minor species in Titan’s atmosphere call for the evaluation of possible influencing factors in photochemical modeling. The effect of nitrogen photoabsorption cross section selection on the modeled vertical profiles of minor species is analyzed here, with particular focus on C{sub 2}H{sub 6} and HCN. Our results show a clear impact of cross sections used on all neutral and ion species studied. Affected species include neutrals and ions that are not primary photochemical products, including species that do not even contain nitrogen. The results indicate that photochemical models that employ low-resolution cross sections may significantly miscalculate the vertical profiles of minor species. Such differences are expected to have important implications for Titan’s overall atmospheric structure and chemistry.

  4. Broad spectrum bioactive sunscreens.

    Science.gov (United States)

    Velasco, Maria Valéria Robles; Sarruf, Fernanda Daud; Salgado-Santos, Idalina Maria Nunes; Haroutiounian-Filho, Carlos Alberto; Kaneko, Telma Mary; Baby, André Rolim

    2008-11-03

    The development of sunscreens containing reduced concentration of chemical UV filters, even though, possessing broad spectrum effectiveness with the use of natural raw materials that improve and infer UV absorption is of great interest. Due to the structural similarities between polyphenolic compounds and organic UV filters, they might exert photoprotection activity. The objective of the present research work was to develop bioactive sunscreen delivery systems containing rutin, Passiflora incarnata L. and Plantago lanceolata extracts associated or not with organic and inorganic UV filters. UV transmission of the sunscreen delivery system films was performed by using diffuse transmittance measurements coupling to an integrating sphere. In vitro photoprotection efficacy was evaluated according to the following parameters: estimated sun protection factor (SPF); Boot's Star Rating category; UVA/UVB ratio; and critical wavelength (lambda(c)). Sunscreen delivery systems obtained SPF values ranging from 0.972+/-0.004 to 28.064+/-2.429 and bioactive compounds interacted with the UV filters positive and negatively. This behavior may be attributed to: the composition of the delivery system; the presence of inorganic UV filter and quantitative composition of the organic UV filters; and the phytochemical composition of the P. incarnata L. and P. lanceolata extracts. Among all associations of bioactive compounds and UV filters, we found that the broad spectrum sunscreen was accomplished when 1.68% (w/w) P. incarnata L. dry extract was in the presence of 7.0% (w/w) ethylhexyl methoxycinnamate, 2.0% (w/w) benzophenone-3 and 2.0% (w/w) TiO(2). It was demonstrated that this association generated estimated SPF of 20.072+/-0.906 and it has improved the protective defense against UVA radiation accompanying augmentation of the UVA/UVB ratio from 0.49 to 0.52 and lambda(c) from 364 to 368.6nm.

  5. Photoabsorption in molecular nitrogen: A moment analysis of discrete-basis-set calculations in the static-exchange approximation

    International Nuclear Information System (INIS)

    Rescigno, T.N.; Bender, C.F.; McKoy, B.V.; Langhoff, P.W.

    1978-01-01

    Theoretical investigations of photoexcitation and ionization cross sections in molecular nitrogen are reported employing the recently devised Stieltjes--Tchebycheff moment-theory technique in the static-exchange approximation. The coupled-channel equations for photoabsorption are separated approximately by identifying the important physically distinct excitation processes associated with formation of the three lowest electronic states of the parent molecular ion. Approximate Rydberg series and pseudospectra of transition frequencies and oscillator strengths are constructed for the seven individual channel components identified using Hartree--Fock ionic core functions and normalizable Gaussian orbitals to describe the photoexcited and ejected electrons. Detailed comparisons of the theoretically determined discrete excitation series with available spectral data indicate general accord between the calculated and observed excitation frequencies and oscillator strengths, although there are some discrepancies and certain Rydberg series have apparently not yet been identified in the measured spectra. The total Stieltjes--Tchebycheff vertical photoionization cross section obtained from the discrete pseudospectra is in excellent agreement with recent electron--ion coincidence measurement of the cross section for parent--ion production from threshold to 50 eV excitation energy. Similarly, e calculated vertical partial cross sections for the production of the three lowest electronic states in the parent molecular ion are in excellent accord with the results of recent electron--electron coincidence and synchrotron--radiation branching ratio measurements. The origins of particularly intense resonancelike features in the discrete and continuum portions of the photoabsorption cross sections are discussed in terms of excitations into valencelike molecular orbitals

  6. Using DNA origami nanostructures to determine absolute cross sections for UV photon-induced DNA strand breakage.

    Science.gov (United States)

    Vogel, Stefanie; Rackwitz, Jenny; Schürman, Robin; Prinz, Julia; Milosavljević, Aleksandar R; Réfrégiers, Matthieu; Giuliani, Alexandre; Bald, Ilko

    2015-11-19

    We have characterized ultraviolet (UV) photon-induced DNA strand break processes by determination of absolute cross sections for photoabsorption and for sequence-specific DNA single strand breakage induced by photons in an energy range from 6.50 to 8.94 eV. These represent the lowest-energy photons able to induce DNA strand breaks. Oligonucleotide targets are immobilized on a UV transparent substrate in controlled quantities through attachment to DNA origami templates. Photon-induced dissociation of single DNA strands is visualized and quantified using atomic force microscopy. The obtained quantum yields for strand breakage vary between 0.06 and 0.5, indicating highly efficient DNA strand breakage by UV photons, which is clearly dependent on the photon energy. Above the ionization threshold strand breakage becomes clearly the dominant form of DNA radiation damage, which is then also dependent on the nucleotide sequence.

  7. Is UV-A radiation a cause of malignant melanoma?

    International Nuclear Information System (INIS)

    Moan, J.

    1994-01-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs

  8. Is UV-A radiation a cause of malignant melanoma. Er UV-A aarsak til malignt melanom

    Energy Technology Data Exchange (ETDEWEB)

    Moan, J. (Det Norske Radiumhospital, Oslo (Norway))

    1994-03-01

    The first action spectrum for cutaneous malignant melanoma was published recently. This spectrum was obtained using the fish Xiphophorus. If the same action spectrum applies to humans, the following statements are true: Sunbathing products (agents to protect against the sun) that absorb UV-B radiation provide almost no protection against cutaneous malignant melanoma. UV-A-solaria are more dangerous than expected so far. If people are determined to use artificial sources of radiation for tanning, they should choose UV-B solaria rather than UV-A-solaria. Fluorescent tubes and halogen lamps may have weak melanomagenic effects. Ozone depletion has almost no effect on the incidence rates of CMM, since ozone absorbs very little UV-A radiation. Sunbathing products which contain UV-A-absorbing compounds or neutral filter (like titanium oxide) provide real protection against cutaneous malignant melanoma, at least if they are photochemically inert. 34 refs., 2 figs.

  9. Photoabsorption and time-of-flight mass spectroscopy for gas-phase trimethyl phosphate following valence shell excitation

    Energy Technology Data Exchange (ETDEWEB)

    Homem, M.G.P.; Rosa, L.F.S.; Farenzena, L.S.; Hasse, A. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Iza, P. [Escuela Superior Politecnica del Litoral, Guayaquil Guaya (Ecuador); Cavasso Filho, R.L. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil); Lee, M.T.; Iga, I. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil)

    2012-07-01

    Full text: In this work we report an experimental study on photoabsorption of trimethyl phosphate (TMP) molecules in the vacuum-ultraviolet energy range. More specifically, absolute photoabsorption cross sections and photoionization yields are measured and reported in the (11.11-21.45) eV energy range. The photoionization and neutral-decay cross sections in absolute scale are also derived and reported. Details of our experimental setup and procedure for cross-section determination can be found in our previous work [1]. Essentially, the measurements were performed using a double-ion-chamber technique [2]. The experimental cross-section results are analyzed in comparison with PES measurements. Oscillator strengths sum rules over the extrapolated experimental data gives a value of 71.6 au for the static dipole polarizability of TMP, which is in excellent agreement with the value of 72.3 au reported in literature. In addition, the ionic dissociation in the same energy range has been studied by time-of-flight mass spectrometry [3]. The detected product cations are C{sub 3}H{sub 9}O{sub 4}P{sup +}, C{sub 3}H{sub 8}O{sub 4}P{sup +}, CH{sub 3}O{sub 4}P{sup +}, C{sub 2}H{sub 6}O{sub 3}P{sup +}, PO{sub 4}{sup +}, CH{sub 5}O{sub 2}P{sup +}, PO{sub 3}{sup +}, and CH{sub 3}{sup +}. The observed ionic branching ratios are converted in absolute scale by using the measured photoionization cross sections. The presence of two ionic metastable states corresponding to the C{sub 3}H{sub 9}O{sub 4}P{sup +} and CH{sub 3}O{sub 4}P{sup +} fragments are reported and their metastable ion mean lives are estimated in (152{+-}5) ns and (248{+-}30) ns. The results and discussion will be presented during the workshop. [1] M. G. P. Homem, P. Iza, L. S. Farenzena, R. L. Cavasso-Filho, M. T. Lee and I. Iga, J. Phys. B: At. Mol. Opt. Phys. 42, 235204 (2009). [2] J. A. R. Samson and Lifeng Yin, J. Opt. Soc. Am B 6, 2326 (1989). [3] F. Burmeister, L. H. Coutinho, R. R. T. Marinho, M. G. P. Homem, M. A

  10. Photoabsorption and time-of-flight mass spectroscopy for gas-phase trimethyl phosphate following valence shell excitation

    International Nuclear Information System (INIS)

    Homem, M.G.P.; Rosa, L.F.S.; Farenzena, L.S.; Hasse, A.; Iza, P.; Cavasso Filho, R.L.; Lee, M.T.; Iga, I.

    2012-01-01

    Full text: In this work we report an experimental study on photoabsorption of trimethyl phosphate (TMP) molecules in the vacuum-ultraviolet energy range. More specifically, absolute photoabsorption cross sections and photoionization yields are measured and reported in the (11.11-21.45) eV energy range. The photoionization and neutral-decay cross sections in absolute scale are also derived and reported. Details of our experimental setup and procedure for cross-section determination can be found in our previous work [1]. Essentially, the measurements were performed using a double-ion-chamber technique [2]. The experimental cross-section results are analyzed in comparison with PES measurements. Oscillator strengths sum rules over the extrapolated experimental data gives a value of 71.6 au for the static dipole polarizability of TMP, which is in excellent agreement with the value of 72.3 au reported in literature. In addition, the ionic dissociation in the same energy range has been studied by time-of-flight mass spectrometry [3]. The detected product cations are C 3 H 9 O 4 P + , C 3 H 8 O 4 P + , CH 3 O 4 P + , C 2 H 6 O 3 P + , PO 4 + , CH 5 O 2 P + , PO 3 + , and CH 3 + . The observed ionic branching ratios are converted in absolute scale by using the measured photoionization cross sections. The presence of two ionic metastable states corresponding to the C 3 H 9 O 4 P + and CH 3 O 4 P + fragments are reported and their metastable ion mean lives are estimated in (152±5) ns and (248±30) ns. The results and discussion will be presented during the workshop. [1] M. G. P. Homem, P. Iza, L. S. Farenzena, R. L. Cavasso-Filho, M. T. Lee and I. Iga, J. Phys. B: At. Mol. Opt. Phys. 42, 235204 (2009). [2] J. A. R. Samson and Lifeng Yin, J. Opt. Soc. Am B 6, 2326 (1989). [3] F. Burmeister, L. H. Coutinho, R. R. T. Marinho, M. G. P. Homem, M. A. A. Morais, A. Mocellin, O. Bjorneholm, S. L. Sorensen, P. T. Fonseca, A. Lindgren and A. Naves de Brito, J. Electron Spectrosc

  11. UV spectrophotometry of the Metronidazole

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-10-01

    Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

  12. UV-induced N2O emission from plants

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2014-01-01

    investigate for the fi rst time N 2 O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted fi eld site measurements to investigate N 2 O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory...... magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N 2 O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process...

  13. UV dose-effect relationships and current protection exposure standards

    International Nuclear Information System (INIS)

    Singh, M.S.; Campbell, G.W.

    1982-04-01

    In this paper we have attempted to quantify the health effects in man of uv-radiation exposure of wavelengths from 240 nm to 320 nm. Exposure to uv in this region could result in the formation of skin cancer or premature aging in man. The induction of cancer by uv radiation results from changes in genetic material. We have used the DNA action spectrum coupled with the uv skin cancer data available in the literature to derive the dose-effect relationships. The results are compared against the current uv protection standards

  14. Time-Resolved K-shell Photoabsorption Edge Measurement in a Strongly Coupled Matter Driven by Laser-converted Radiation

    Science.gov (United States)

    Zhao, Yang; Yang, Jia-Min; Zhang, Ji-Yan; Yang, Guo-Hong; Xiong, Gang; Wei, Min-Xi; Song, Tian-Ming; Zhang, Zhi-Yu

    2013-06-01

    A time-resolved K edge absorption measurement of warm dense KCl was performed on Shenguang II laser facility. The x-ray radiation driven shocks were adopted to take colliding shocks compression. By using Dog bone hohlraum the CH/KCl/CH sample was shielded from the laser hitting point to suppress the M band preheating and enhance the compressibility. Thus, an unexplored and extreme region of the plasma state with the maximum 5 times solid density and temperature lower than 3 eV (with coupling constant Γii around 100) was first obtained. The photoabsorption spectra of chlorine near the K-shell edge have been measured with a crystal spectrometer using a short x-ray backlighter. The K edge red shift up to 11.7 eV and broadening of 15.2 eV were obtained for the maximum compression. The electron temperature, inferred by Fermi-Dirac fit of the measured K-edge broadening, was consistent with the hydrodynamic predictions. The comparison of the K edge shift with a plasma model, in which the ionization effect, continuum lowering and partial degeneracy are considered, shows that more improvements are desired to describe in details the variation of K edge shift. This work might extend future study of WDM in extreme conditions of high compression.

  15. Changes in UV absorption of sunscreens after UV irradiation

    Science.gov (United States)

    Tarras-Wahlberg, N.; Stenhagen, G.; Larkö, O.; Rosén, A.; Wennberg, A.-M.; Wennerström, O.

    2000-03-01

    In the present investigation we have studied the change in the absorption spectrum of some photoactive organic species in sunscreens after UVA and UVB irradiation in a dose normally encountered during a full day in the sun. The absorbance of 2-ethylhexyl 4-methoxycinnamate was reduced significantly, while 3-(4-methylbenzyliden)camphor seemed to be rather stable. The benzophenones studied seemed to be relatively stable. In the case of 4-tert.butyl-4´-methoxy-dibenzoylmethane there was a rapid decrease in the UVA absorption leading to unsatisfactory protection in the UVA region. 4-Isopropyl-dibenzoylmethane also lost most of its UV protective capacity after irradiation with UVA. UVB seemed to have a minor effect on all the samples. The present study including gas chromatography and mass spectrometry analysis indicates that some of the photoactive organic species commonly used today in sunscreens are unstable following UV irradiation.

  16. The electronic states of 1,2,4-triazoles: A study of 1H- and1-methyl-1,2,4-triazole by vacuum ultraviolet photoabsorption and ultraviolet photoelectron spectroscopy and a comparison with ab initio configuration interaction computations

    DEFF Research Database (Denmark)

    Palmer, Michael H.; Camp, Philip J.; Hoffmann, Søren Vrønning

    2012-01-01

    The first vacuum ultraviolet absorption spectrum of a 1,2,4-triazole has been obtained and analyzed in detail, with assistance from both an enhanced UV photoelectron spectroscopic study and ab initio multi-reference multi-root configuration interaction procedures. For both 1H- and 1-methyl-1,2...

  17. Total photoabsorption cross sections for {sup 1}H, {sup 2}H and {sup 3}He from 200 to 800 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Mac Cormick, M.; Audit, G. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Altieri, S.; Braghieri, A. [Istituto Nazionale di Fisica Nucleare, Pavia (Italy)]|[Pavia Univ. (Italy). Ist. di Fisica Nucleare; Ahrens, J.; Beck, R. [Mainz Univ. (Germany). Inst. fuer Kernphysik; Annand, J.R.M.; Crawford, R.A. [Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy; Dolbilkin, B.; Zabrodin, A. [AN SSSR, Moscow (Russian Federation). Inst. Yadernykh Issledovanij] [and others

    1996-01-01

    The total photoabsorption cross sections for {sup 1}H, {sup 2}H and {sup 3}He have been measured for incident photon energies ranging from 200 to 800 MeV. The results show clearly the changes in the nucleon resonances in going from {sup 1}H to {sup 3}He. In particular, for the D{sub 13} region the behaviour for {sup 3}He is intermediate between that for {sup 1}H, {sup 2}H and heavier nuclei. (author). Submitted to Physical Review, C (US); 26 refs.

  18. Índice UV

    Science.gov (United States)

    Información general sobre el Índice UV que proporciona un pronóstico del riesgo esperado de sobreexposición a la radiación ultravioleta (UV) del sol. El índice UV va acompañado de recomendaciones para protegerse del sol.

  19. uv dye lasers

    International Nuclear Information System (INIS)

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  20. Influence of uvrB and pKM101 on the spectrum of spontaneous, UV- and gamma-ray-induced base substitutions that revert hisG46 in Salmonella typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    Eisenstadt, E; Kahng, L -S; Miller, J K; Barnes, W M

    1989-01-01

    Oligonucleotide probes were used to identify base substitutions in 1089 revertants of hisG46 in Salmonella typhimurium that arose spontaneously or following irradiation with UV- or ..gamma..-rays. The hisG46 allele, carrying a mutant CCC codon (Pro) in place of the wild-type codon CTC (Leu69) reverted via 6 distinguishable mutational events: C to T transitions at codon sites 1 or 2, C to A or C to G transversions at codon site 1, C to A at codon site 2, and an extragenic suppressor mutation. The distribution of hisG46 revertants differed among treatments and was influenced by the DNA-repair capacity of the bacteria. Plasmid pKM101 enhanced the frequencies of both spontaneous adn induced mutations; transversion events were enhanced more efficiently by pKM101 than were transition events. Compared to Uvr/sup +/ bacteria, Uvr/sup -/ bacteria had higher frequencies of spontaneous and induced mutations; transition mutations were enhanced more efficiently than were transversion mutations. The inflence of DNA-repair activiteis on the mutational spectra provides some insights on the origins of spontaneous and UV-induced mutations. (author). 75 refs.; 4 figs.; 4 tabs.

  1. Theory of monochromators based on holographic toroidal arrays for the X-UV spectrum band. Tests of the 'TGM 10 metres, 4 degrees' on the ACO storage ring

    International Nuclear Information System (INIS)

    Lizon a Lugrin, Eric

    1988-01-01

    As the use of synchrotron radiation is strongly increasing, needs for monochromators in the X-UV range are very important. This research thesis aimed at the development of prototype monochromator based toroidal lamellar arrays with grazing incidence. In the first part, the author recalls theoretical aspects of light scattering rules adapted to a lamellar array, and of wave-matter interaction rules. In the second part, he reports the calculation of the monochromator, its mechanical description, and its implementation on the light line of the ACO storage ring. In the third part, the author reports tests performed without any input slot and in reverse optical configuration on the ACO storage ring. The energy range, the linearity with respect to wave length, the rejection of higher orders of scattered light, flow and resolution are in compliance with expected values [fr

  2. UV exposure in cars.

    Science.gov (United States)

    Moehrle, Matthias; Soballa, Martin; Korn, Manfred

    2003-08-01

    There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of 'adult' and 'child' dummies. UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3-4% of ambient radiation when the car windows were shut, and 25-31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.

  3. Quantification of biologically effective environmental UV irradiance

    Science.gov (United States)

    Horneck, G.

    To determine the impact of environmental UV radiation on human health and ecosystems demands monitoring systems that weight the spectral irradiance according to the biological responses under consideration. In general, there are three different approaches to quantify a biologically effective solar irradiance: (i) weighted spectroradiometry where the biologically weighted radiometric quantities are derived from spectral data by multiplication with an action spectrum of a relevant photobiological reaction, e.g. erythema, DNA damage, skin cancer, reduced productivity of terrestrial plants and aquatic foodweb; (ii) wavelength integrating chemical-based or physical dosimetric systems with spectral sensitivities similar to a biological response curve; and (iii) biological dosimeters that directly weight the incident UV components of sunlight in relation to the effectiveness of the different wavelengths and to interactions between them. Most biological dosimeters, such as bacteria, bacteriophages, or biomolecules, are based on the UV sensitivity of DNA. If precisely characterized, biological dosimeters are applicable as field and personal dosimeters.

  4. UV-induced effects

    NARCIS (Netherlands)

    Liebsch, M.; Spielmann, H.; Pape, W.; Krul, C.; Deguercy, A.; Eskes, C.A.M.

    2005-01-01

    Regulatory requirements: According to the current Notes for Guidance of the Scientific Committee on Cosmetic Products and Non-Food Products (SCCNFP), cosmetic ingredients and mixtures of ingredients absorbing UV light (in particular UV filter chemicals used, for example, to ensure the light

  5. A UV-Vis photoacoustic spectrophotometer.

    Science.gov (United States)

    Wiegand, Joseph R; Mathews, L Dalila; Smith, Geoffrey D

    2014-06-17

    A novel photoacoustic spectrophotometer (PAS) for the measurement of gas-phase and aerosol absorption over the UV-visible region of the spectrum is described. Light from a broadband Hg arc lamp is filtered in eight separate bands from 300 to 700 nm using bandpass interference filters (centered at 301 nm, 314 nm, 364 nm, 405 nm, 436 nm, 546 nm, 578 and 687 nm) and modulated with an optical chopper before entering the photoacoustic cell. All wavelength bands feature a 20-s detection limit of better than 3.0 Mm(-1) with the exception of the lower-intensity 687 nm band for which it is 10.2 Mm(-1). Validation measurements of gas-phase acetone and nigrosin aerosol absorption cross sections at several wavelengths demonstrate agreement to within 10% with those measured previously (for acetone) and those predicted by Mie theory (for nigrosin). The PAS instrument is used to measure the UV-visible absorption spectrum of ambient aerosol demonstrating a dramatic increase in the UV region with absorption increasing by 300% from 405 to 301 nm. This type of measurement throughout the UV-visible region and free from artifacts associated with filter-based methods has not been possible previously, and we demonstrate its promise for classifying and quantifying different types of light-absorbing ambient particles.

  6. Electronic properties of metal-organic and organic-organic interfaces studied by photoemission and photoabsorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Molodtsova, Olga

    2006-07-01

    In this work systematic studies of the organic semiconductor CuPc have been presented. In general the investigation can be devided in three parts. In the first one we have studied the electronic structure of clean CuPc thin film. The next two parts are devoted to organic-organic and metal-organic interface formation, where one of the interface components is CuPc thin film. The main results of this thesis are: - The electronic structure of the pristine organic semiconductor CuPc has been obtained by a combination of conventional and resonant photoemission, near-edge X-ray absorption, as well as by theoretical ab initio quantum-chemical calculations. The contributions of different atomic species as well as sites of the CuPc molecule to the electronic DOS has been established. A combined experimental and theoretical study of the unoccupied electronic density of states of CuPc was presented. - The electronic properties of the organic heterointerfaces between fullerite and pristine copper phthalocyanine were studied. Both interfaces, CuPc/C{sub 60} and C{sub 60}/CuPc, were found to be non-reactive with pronounced shifts of the vacuum level pointing to the formation of an interfacial dipole mainly at the CuPc side of the heterojunctions. The dipole values are close to the difference of the work functions of the two materials. Important interface parameters and hole-injection barriers were obtained. The sequence of deposition does not influence the electronic properties of the interfaces. - CuPc doped with potassium was studied by means of photoemission and photoabsorption spectroscopy. A detailed analysis of the core-level PE spectra allows one to propose possible lattice sites, which harbor the potassium ions. The films prepared in this thesis showed no finite electronic density of states at the Fermi level. - Two stages of the In/CuPc interface formation have been distinguished. The low-coverage stage is characterized by a strong diffusion of the In atoms into the

  7. Alfalfa seedlings grown outdoors are more resistant to UV-induced DNA damage than plants grown in a UV-free environmental chamber

    International Nuclear Information System (INIS)

    Takayanagi, Shinnosuke; Trunk, J.G.; Sutherland, J.C.; Sutherland, B.M.

    1994-01-01

    The relative UV sensitivities of alfalfa seedlings grown outdoors versus plants grown in a growth chamber under UV-filtered cool white fluorescent bulbs have been determined using three criteria: (1) level of endogenous DNA damage as sites for the UV endonuclease from Micrococcus luteus, (2) susceptibility to pyrimidine dimer induction by a UV challenge exposure and (3) ability to repair UV-induced damage. We find that outdoor-grown plants contain approximately equal frequencies of endogenous DNA damages, are less susceptible to dimer induction by a challenge exposure of broad-spectrum UV and photorepair dimers more rapidly than plants grown in an environmental chamber under cool white fluorescent lamps plus a filter removes most UV radiation. These data suggest that plants grown in a natural environment would be less sensitive to UVB-induced damage than would be predicted on the basis of studies on plants grown under minimum UV. (author)

  8. UV “Indices”—What Do They Indicate?

    Directory of Open Access Journals (Sweden)

    Hanns Moshammer

    2016-10-01

    Full Text Available Ultra-Violet (UV radiation covers the spectrum of wavelengths from 100 to 400 nm. The potency and biological activity for a variety of endpoints differ by wavelength. For monitoring and communication purposes, different UV action spectra have been developed. These spectra use different weighting functions. The action spectrum for erythemal dose is the most widely used one. This erythemal dose per time or dose-rate has been further simplified into a “UV index”. Following this example, in our review we use the term “index” or (plural “indices” in a more general description for all simplified single-value measures for any biologically effective UV dose, e.g., for human non-melanoma skin cancer and for previtamin D production rate. Ongoing discussion about the existence of an increased melanoma risk due to UV-A exposure underscores the uncertainties inherent in current weighting functions. Thus, we performed an online literature search to review the data basis for these indices, to understand their relevance for an individual, and to assess the applicability of the indices for a range of exposure scenarios. Even for natural (solar UV, the spectral composition varies spatially and temporally. Artificial UV sources and personal protection introduce further variation to the spectral composition. Many biological effects are proposed for UV radiation. Only few endpoints have been studied sufficiently to estimate a reliable index. Weighting functions for chronic effects and most importantly for cancer endpoints have been developed in animal models, and often for proxy endpoints only. Epidemiological studies on biological effects of UV radiation should not only depend on single-value weighted UV dose estimates (indexes but should strive for a more detailed description of the individual exposure. A better understanding of the adverse and beneficial effects of UV radiation by wavelength would also improve medical counseling and health

  9. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  10. Spectrum Recombination.

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    1984-01-01

    Describes several methods of executing lecture demonstrations involving the recombination of the spectrum. Groups the techniques into two general classes: bringing selected portions of the spectrum together using lenses or mirrors and blurring the colors by rapid movement or foreshortening. (JM)

  11. Enhancement of root growth and nitrogen fixation in Trigonella by UV-exclusion from solar radiation.

    Science.gov (United States)

    Sharma, Sonika; Guruprasad, K N

    2012-12-01

    A field experiment was conducted to study the impact of solar UV on root growth and nitrogen fixation in Trigonella foenum-graecum. Plants were grown in iron mesh cages covered with polyester filters that could specifically cut off UV-B (280-315 nm) or UV-A + B (280-400 nm) part of the solar spectrum. The control plants were grown under a polythene filter transmissible to UV. Root biomass, number of nodules and nodule fresh weight were enhanced after exclusion of solar UV. Nitrogenase activity was significantly enhanced by 120% and 80% in the UV-B and UV-A + B excluded plants respectively. Along with nitrogenase there was concomitant increase in leghemoglobin and hemechrome content in the nodules after exclusion of solar UV. These components of sunlight limits nitrogen fixation and their elimination can enhance nitrogen fixation with agricultural advantages like reduction in the use of fertilizers. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  12. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation.

    Science.gov (United States)

    Siipola, Sari M; Kotilainen, Titta; Sipari, Nina; Morales, Luis O; Lindfors, Anders V; Robson, T Matthew; Aphalo, Pedro J

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors. © 2014 John Wiley & Sons Ltd.

  13. Dependence of UV effect on quality of light during raising of seedlings (Lactuca sativa L.)

    International Nuclear Information System (INIS)

    Bogenrieder, A.; Klein, R.

    1978-01-01

    Greenhouse seedlings of Lactuca sativa L. show a decreased rate of photosynthesis under normal outdoor light conditions due to the effect of UV-light. In this study, the relationship between the declining rate of photosynthesis and the amount of UV in the spectrum was investigated. The determination was made in climatized gas exchange chambers under Xenon arc lamps (XBO 2500 W, Osram). The amount of UV in the spectrum was varied by the use of different surface mirrors made by aluminium evaporation. A linear relationship between the amount of UV-light in the spectrum and the rate of decrease of photosynthesis was obtained with 12 hour radiation. The decrease in photosynthesis is less when the plants are raised under UV-light lamps. (orig.) [de

  14. Risks of increased UV-B radiation for humans

    International Nuclear Information System (INIS)

    Przybilla, B.; Eberlein-Koenig, B.; Bergner, T.

    1994-01-01

    If not compensated in any way, depletion of the stratospheric ozone layer leads to an increase of UV-B radiation at the earth's surface, especially towards the short-wave range, which is biologically the more active. The most concerning effect here is that of UV-B induced skin reactions, in particular malignant skintumors (malignant melanoma, spinocellular carcinoma, basalioma), whose incidence is expected to increase in future. As some photoreactions can be inhibited or enhanced also by radiation outside their action spectrum, it is possible for changes in solar spectral radiation flux density to influence photo-induced reactions that are driven at wavelengths outside the UV-B range. The authors have performed studies for developing methods of quantifying individual UV sensitivity. In vitro studies have shown that UV-A dependent photoreactions can be partly inhibited by UV-B. A number of drugs, as well as sulphites, which are used as preservatives amongst other things, have been shown to have phototoxic properties that may be relevant to photocarcinogenesis. Irradiation tests on cell cultures for different UV-B ranges have shown that irradiation at shorter wavelengths leads to a stronger release of proinflammatory cytokines that ar longer wavelengths with the same dose. Altogether it can be said that despite compelling theoretical evidence it is not easily possible to predict the actual consequences of an increase in particular of short-wave UV-B radiation at the earth's surface. The assumed effects must be examined individually by appropriate methods. (orig.) [de

  15. Growth enhancement of soybean (Glycine max) upon exclusion of UV-B and UV-B/A components of solar radiation: characterization of photosynthetic parameters in leaves.

    Science.gov (United States)

    Guruprasad, Kadur; Kadur, Guruprasad; Bhattacharjee, Swapan; Swapan, Bhattacharjee; Kataria, Sunita; Sunita, Kataria; Yadav, Sanjeev; Sanjeev, Yadav; Tiwari, Arjun; Arjun, Tiwari; Baroniya, Sanjay; Sanjay, Baroniya; Rajiv, Abhinav; Abhinav, Rajiv; Mohanty, Prasanna

    2007-01-01

    Exclusion of UV (280-380 nm) radiation from the solar spectrum can be an important tool to assess the impact of ambient UV radiation on plant growth and performance of crop plants. The effect of exclusion of UV-B and UV-A from solar radiation on the growth and photosynthetic components in soybean (Glycine max) leaves were investigated. Exclusion of solar UV-B and UV-B/A radiation, enhanced the fresh weight, dry weight, leaf area as well as induced a dramatic increase in plant height, which reflected a net increase in biomass. Dry weight increase per unit leaf area was quite significant upon both UV-B and UV-B/A exclusion from the solar spectrum. However, no changes in chlorophyll a and b contents were observed by exclusion of solar UV radiation but the content of carotenoids was significantly (34-46%) lowered. Analysis of chlorophyll (Chl) fluorescence transient parameters of leaf segments suggested no change in the F v/F m value due to UV-B or UV-B/A exclusion. Only a small reduction in photo-oxidized signal I (P700+)/unit Chl was noted. Interestingly the total soluble protein content per unit leaf area increased by 18% in UV-B/A and 40% in UV-B excluded samples, suggesting a unique upregulation of biosynthesis and accumulation of biomass. Solar UV radiation thus seems to primarily affect the photomorphogenic regulatory system that leads to an enhanced growth of leaves and an enhanced rate of net photosynthesis in soybean, a crop plant of economic importance. The presence of ultra-violet components in sunlight seems to arrest carbon sequestration in plants.

  16. A study of the valence shell electronic states of s-triazine by photoabsorption spectroscopy and ab initio calculations

    DEFF Research Database (Denmark)

    Holland, D.M.P.; Shaw, D.A.; Stener, Mauro

    2016-01-01

    absorption bands due to excitation from the 1e00 or 6e0 orbitals. The interpretation of the experimental spectrum has been guided by transition energies and oscillator strengths, for Rydberg and valence states, calculated with the time-dependent version of density functional theory and with the coupled...... cluster linear response approach. The theoretical studies indicate that Rydberg/Rydberg and Rydberg/valence mixing is important....

  17. UV Spectroscopy of Metallic Asteroid (16) Psyche

    Science.gov (United States)

    Cunningham, N. J.; Becker, T. M.; Retherford, K. D.; Roth, L.; Feaga, L. M.; Wahlund, J.-E.; Elkins-Tanton, L. T.

    2017-09-01

    Asteroid (16) Psyche is the largest M-type asteroid, and the planned destination of the NASA Discovery mission Psyche and the proposed ESA M5 mission Heavy Metal. Psyche is considered to be the exposed core of a differentiated asteroid, whose mantle has been stripped by collisions; but other histories have been proposed. We observed Psyche with the Space Telescope Imaging Spectrograph (STIS) and Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope, to obtain a full ultraviolet (UV) spectrum of both of Psyche's hemispheres. We seek to test three possible scenarios for Psyche's origin: Is Psyche the exposed core of a differentiated asteroid? Is it an asteroid with high olivine content that has been space-weathered? Or did Psyche accrete as-is in a highly-reducing environment early in the history of the solar system? We will present the UV spectra and their implications for Psyche's history.

  18. High Average Power UV Free Electron Laser Experiments At JLAB

    International Nuclear Information System (INIS)

    Douglas, David; Benson, Stephen; Evtushenko, Pavel; Gubeli, Joseph; Hernandez-Garcia, Carlos; Legg, Robert; Neil, George; Powers, Thomas; Shinn, Michelle; Tennant, Christopher; Williams, Gwyn

    2012-01-01

    Having produced 14 kW of average power at ∼2 microns, JLAB has shifted its focus to the ultraviolet portion of the spectrum. This presentation will describe the JLab UV Demo FEL, present specifics of its driver ERL, and discuss the latest experimental results from FEL experiments and machine operations.

  19. Possibilities of UV laser oscillation on aluminium ion lines

    NARCIS (Netherlands)

    Grozeva, M.; Mihailova, D.B.; Sabotinov, N.

    2006-01-01

    An analysis of the general energy level structure of the singly ionised Al is made. It is found that in the UV spectrum of Al II there are many intensive lines starting from levels which can be populated selectively via charge transfer collisions with either helium or neon ions. The emission

  20. UV spectroscopy. Ch. 16

    International Nuclear Information System (INIS)

    Stevens, Eugene S.

    1991-01-01

    The use of synchrotron radiation (SR) in the ultraviolet (UV) region by biophysics and biophysical chemists continues to increase as access improves and as awareness of its unique combination of properties grows. SR is continuously tunable, intense (even in the UV region), and pulsed. Pulse characteristics are comparable to those of picosecond lasers, but have the advantage of being independent of wavelength. Drawbacks are the continuous, but slow, decay of intensity arising from loss of particles in the ring, and the intrinsic limitation in pulse repetition rate. The particular combination of features that makes SR a superior light source depends upon the application. Spectroscopic techniques based on absorption and some techniques based on emission exploit its intensity and continuous tunability; time resolved techniques make use of its pulse characteristics. This chapter is a status report on two of the major biological applications of UV SR, circular dichroism and time-resolved fluorescence, covering mainly the published literature of the last five years. For the present purpose, the term UV is understood to include the vacuum ultraviolet region to 100 nm. (author). 83 refs.; 4 figs.; 6 tabs

  1. A UV flux constraint on the formation of direct collapse black holes

    NARCIS (Netherlands)

    Latif, M. A.; Bovino, S.; Van Borm, C.; Grassi, T.; Schleicher, D. R. G.; Spaans, Marco

    2014-01-01

    The ability of metal-free gas to cool by molecular hydrogen in primordial haloes is strongly associated with the strength of ultraviolet (UV) flux produced by the stellar populations in the first galaxies. Depending on the stellar spectrum, these UV photons can either dissociate H2 molecules

  2. Photoabsorption and S 2p photoionization of the SF6 molecule: resonances in the excitation energy range of 200-280 eV.

    Science.gov (United States)

    Stener, M; Bolognesi, P; Coreno, M; O'Keeffe, P; Feyer, V; Fronzoni, G; Decleva, P; Avaldi, L; Kivimäki, A

    2011-05-07

    Photoabsorption and S 2p photoionization of the SF(6) molecule have been studied experimentally and theoretically in the excitation energy range up to 100 eV above the S 2p ionization potentials. In addition to the well-known 2t(2g) and 4e(g) shape resonances, the spin-orbit-resolved S 2p photoionization cross sections display two weak resonances between 200 and 210 eV, a wide resonance around 217 eV, a Fano-type resonance around 240 eV, and a second wide resonance around 260 eV. Calculations based on time-dependent density functional theory allow us to assign the 217-eV and 260-eV features to the shape resonances in S 2p photoionization. The Fano resonance is caused by the interference between the direct S 2p photoionization channel and the resonant channel that results from the participator decay of the S 2s(-1)6t(1u) excited state. The weak resonances below 210-eV photon energy, not predicted by theory, are tentatively suggested to originate from the coupling between S 2p shake-up photoionization and S 2p single-hole photoionization. The experimental and calculated angular anisotropy parameters for S 2p photoionization are in good agreement.

  3. Light Conversion and Scattering in UV Protective Textiles

    Directory of Open Access Journals (Sweden)

    Grancarić Ana Marija

    2014-12-01

    Full Text Available The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80% of UV-R gets absorbed, whilst in the remaining 20% gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA, UV-B protective agents, as well as nanoparticles, if applied. Based on electronically excited state by energy of UV-R (usually 340-370 nm, the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420-470 nm of the spectrum. By absorbing UV-A radiation, optical brightened fabrics transform this radiation into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, is very resistant to washing and improves the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene-derived FWAs were applied on cotton fabric in wide concentration

  4. Biobased Nanoparticles for Broadband UV Protection with Photostabilized UV Filters

    NARCIS (Netherlands)

    Hayden, D.R.|info:eu-repo/dai/nl/412640694; Imhof, A.|info:eu-repo/dai/nl/145641600; Velikov, K. P.|info:eu-repo/dai/nl/239483472

    2016-01-01

    Sunscreens rely on multiple compounds to provide effective and safe protection against UV radiation. UV filters in sunscreens, in particular, provide broadband UV protection but are heavily linked to adverse health effects due to the generation of carcinogenic skin-damaging reactive oxygen species

  5. Two UV colours of the central part of M 31

    Science.gov (United States)

    Deharveng, J. M.; Laget, M.; Monnet, G.; Vuillemin, A.

    1976-01-01

    Two photographs of the galaxy M 31 have been obtained in the far UV with a Faust rocket experiment and in the near UV with the S 183 experiment aboard Skylab. Only the central part of the galaxy is detected. Reductions provide both the energy received and the angular area over M 31 from which it is emitted. The UV flux is brighter than expected from extrapolation of the visible spectrum. The distribution below 300 A is rather flat and different from previous OAO-2 observations. These results, combined with Lyman continuum flux evaluation, are used to discuss the temperature and the age of the stars which may be responsible for this anomalous UV distribution.

  6. Zellweger Spectrum

    Science.gov (United States)

    ... severe defect, resulting in essentially nonfunctional peroxisomes. This phenomenon produces the range of severity of the disorders. How is the Zellweger Spectrum Diagnosed? The distinctive shape of the head and face of a child born with one of the diseases of the ...

  7. Conformation of L-Tyrosine Studied by Fluorescence-Detected UV-UV and IR-UV Double-Resonance Spectroscopy

    OpenAIRE

    Inokuchi, Yoshiya; Kobayashi, Yusuke; Ito, Takafumi; Ebata, Takayuki

    2007-01-01

    The laser-induced fluorescence spectrum of jet-cooled L-tyrosine exhibits more than 20 vibronic bands in the 35450-35750 cm-1 region. We attribute these bands to eight conformers by using results of UV-UV hole-burning spectroscopy. These isomers are classified into four groups; each group consists of two rotational isomers that have a similar side-chain conformation but different orientations of the phenolic OH. The splitting of band origins of rotational isomers is 31, 21, 5, and 0 cm-1 for ...

  8. Standardization of UV LED measurements

    Science.gov (United States)

    Eppeldauer, G. P.; Larason, T. C.; Yoon, H. W.

    2015-09-01

    Traditionally used source spectral-distribution or detector spectral-response based standards cannot be applied for accurate UV LED measurements. Since the CIE standardized rectangular-shape spectral response function for UV measurements cannot be realized with small spectral mismatch when using filtered detectors, the UV measurement errors can be several times ten percent or larger. The UV LEDs produce broadband radiation and both their peaks or spectral bandwidths can change significantly. The detectors used for the measurement of these LEDs also have different spectral bandwidths. In the discussed example, where LEDs with 365 nm peak are applied for fluorescent crack-recognition using liquid penetrant (non-destructive) inspection, the broadband radiometric LED (signal) measurement procedure is standardized. A UV LED irradiance-source was calibrated against an FEL lamp standard to determine its spectral irradiance. The spectral irradiance responsivity of a reference UV meter was also calibrated. The output signal of the reference UV meter was calculated from the spectral irradiance of the UV source and the spectral irradiance responsivity of the reference UV meter. From the output signal, both the integrated irradiance (in the reference plane of the reference meter) and the integrated responsivity of the reference meter were determined. Test UV meters calibrated for integrated responsivity against the reference UV meter, can be used to determine the integrated irradiance from a field UV source. The obtained 5 % (k=2) measurement uncertainty can be decreased when meters with spectral response close to a constant value are selected.

  9. Health hazards of UV radiation

    International Nuclear Information System (INIS)

    Matthes, R.

    1994-01-01

    The author describes the effects and health risks of UV exposure. This includes UV effects on the DNS, the eyes, the immune system, and the skin. Finally, recommendations are given for protection against excessive UV exposure on the basis of the IRPA/INIRC guidelines. (orig.) [de

  10. Transverse effects in UV FELs

    International Nuclear Information System (INIS)

    Small, D.W.; Wong, R.K.; Colson, W.B.

    1995-01-01

    In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium's UV FEL

  11. Chemical and UV Mutagenesis.

    Science.gov (United States)

    Bose, Jeffrey L

    2016-01-01

    The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.

  12. UV curable materials development

    Energy Technology Data Exchange (ETDEWEB)

    Parker, B.G.

    1996-12-01

    Adhesives, coatings, and inks were selected for evaluation based on literature search and possible production applications. A differential photocalorimeter was used to measure degree of cure and allow prediction of optimum processing conditions. UV cure equipment were characterized and the ability to size equipment to specific materials cure needs established. Adhesion tests procedures were developed for the adhesives and solvent resistance testing procedures developed for the coatings and inks.

  13. Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial.

    Science.gov (United States)

    Castanedo-Cazares, Juan Pablo; Hernandez-Blanco, Diana; Carlos-Ortega, Blanca; Fuentes-Ahumada, Cornelia; Torres-Álvarez, Bertha

    2014-02-01

    Melasma is an acquired hyperpigmentation on sun-exposed areas. Multiple approaches are used to treat it, but all include broad ultraviolet (UV)-spectrum sunscreens. Visible light (VL) can induce pigmentary changes similar to those caused by UV radiation on darker-skinned patients. To assess the efficacy of sunscreen with broad-spectrum UV protection that contains iron oxide as a VL-absorbing pigment (UV-VL) compared with a regular UV-only broad-spectrum sunscreen for melasma patients exposed to intense solar conditions. Sixty-eight patients with melasma were randomized in two groups to receive either UV-VL sunscreen or UV-only sunscreen, both with sun protection factor ≥ 50, over 8 weeks. All patients received 4% hydroquinone as a depigmenting treatment. At onset and at conclusion of the study, they were assessed by the Melasma Activity and Severity Index (MASI; a subjective scale), colorimetry (L*) and histological analysis of melanin. Sixty-one patients concluded the study. At 8 weeks, the UV-VL group showed 15%, 28% and 4% greater improvements than the UV-only group in MASI scores, colorimetric values and melanin assessments, respectively. UV-VL sunscreen enhances the depigmenting efficacy of hydroquinone compared with UV-only sunscreen in treatment of melasma. These findings suggest a role for VL in melasma pathogenesis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

    Full Text Available UV radiation (UV is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

  15. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND, B.M.

    2001-07-26

    Organisms living on the earth are exposed to solar radiation, including its ultraviolet (UV) components (for general reviews, the reader is referred to Smith [1] and Young et al. [2]). UV wavelength regions present in sunlight are frequently designated as UVB (290-320 nm) and UVA (320-400 nm). In today's solar spectrum, UVA is the principal UV component, with UVB present at much lower levels. Ozone depletion will increase the levels of UVB reaching the biosphere, but the levels of UVA will not be changed significantly [3]. Because of the high efficiency of UVB in producing damage in biological organisms in the laboratory experiments, it has sometimes been assumed that UVA has little or no adverse biological effects. However, accumulating data [4, 5], including action spectra (efficiency of biological damage as a function of wavelength of radiation; see Section 5) for DNA damage in alfalfa seedlings [6], in human skin [7], and for a variety of plant damages (Caldwell, this volume) indicate that UVA can induce damage in DNA in higher organisms. Thus, understanding the differential effects of UVA and UVB wavebands is essential for estimating the biological consequences of stratospheric ozone depletion.

  16. UV dissociation of vibrationally excited UF6

    International Nuclear Information System (INIS)

    Alexandre, M.; Clerc, M.; Gagnon, R.; Gilbert, M.; Isnard, P.; Nectoux, P.; Rigny, P.; Weulersse, J.M.

    1983-01-01

    Before application of laser photodissociation of UF 6 to the separation of uranium isotopes becomes practical, isotopic selectivity should be optimized. We present here results on the cross sections involved in the irradiation of UF 6 simultaneously with infrared and ultraviolet lasers, as a function of wavelengths, fluence and temperature (at 293 K and 105 K, in an adiabatic expansion). The experiment uses a Nd 3+ YAG pumped lithium niobate optical parametric oscillator as a tunable 16 μ light source. Energies of the order of 1 mJ can be obtained with linewidths smaller than 0.1 cm - . The UV source used is based on ND 3+ YAG pumped dye laser and various frequency mixing schemes. At low temperature the frequency variation of the absorbed infrared energy per molecule depends markedly on the IR fluence phisub(IR) with a maximum value varying as phisub(IR)sup(-1/2) and a frequency extension far beyond the low level absorption spectrum. The absorbed vibrational energy leads to a change in the UV cross section comparable with the effect of a rise in temperature. Using this a model is put forward to express the isotopic selectivity 235 U/ 238 U as a function of UV wavelength and IR irradiation conditions. Experimental results agree with this model, and yield to maximum selectivity close to two [fr

  17. UV-NIL replication of microlens arrays on flexible fluoropolymer substrates

    DEFF Research Database (Denmark)

    Jucius, Dalius; Lazauskas, Algirdas; Grigaliūnas, Viktoras

    2018-01-01

    This paper describes application of UV-NIL technique for the fabrication of hexagonal OrmoComp microlens arrays on flexible fluoropolymer substrates having exceptional chemical resistance, stability at elevated temperatures and high transmittance in the UV, visible, and infrared regions...... of the spectrum. Uniform and well-defined patterns of close-packed convex microlenses were formed in OrmoComp layers on H2 plasma treated FEP and ETFE substrates by UV-NIL replication of the metalized and liquid paraffin antiadhesive coated negative OrmoComp replicas of the master mold. UV-NIL replication...

  18. UV-induced N2O emission from plants

    Science.gov (United States)

    Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

    2014-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  19. uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

    Science.gov (United States)

    Chae, S K; Kafer, E

    1993-01-01

    Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

  20. Antiradiation UV Vaccine: UV Radiation, Biological effects, lesions and medical management - immune-therapy and immune-protection.

    Science.gov (United States)

    Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

    Key Words: Ultraviolet radiation,Standard Erythema Dose(SED), Minimal Erythema Dose(MED), Sun Burns, Solar Dermatitis, Sun Burned Disease, DNA Damage,Cell Damage, Antiradiation UV Vaccine, Immune-Prophylaxis of Sun Burned Diseases, Immune-Prophylaxis of Sun Burns, Immune-Therapy of Sun-Burned Disease and Sun Burns,Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), Toxic Epidermal Necrolysis(TEN). Introduction: High doses of UV generated by solar source and artificial sources create an exposure of mammals and other species which can lead to ultraviolet(UV)radiation- associated disease (including erythema, epilation, keratitis, etc.). UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm with 100 nm having been chosen arbitrarily as the boundary between non-ionizing and ionizing radiation, however EMR is a spectrum and UV can produce molecular ionization. UV radiation is conventionally categorized into 3 areas: UV-A (>315-400 nm),UV-B (>280-315 nm)and UV-C (>100-280 nm) [IARC,Working Group Reports,2005] An important consequence of stratospheric ozone depletion is the increased transmission of solar ultraviolet (UV)radiation to the Earth's lower atmosphere and surface. Stratospheric ozone levels have been falling, in certain areas, for the past several decades, so current surface ultraviolet-B (UV-B) radiation levels are thought to be close to their modern day maximum. [S.Madronich et al.1998] Overexposure of ultraviolet radiation a major cause of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) { collectively referred to as “non-melanoma" skin cancer (NMSC) and melanoma as well, with skin cancers being the most common cancer in North America. [Armstrong et al. 1993, Gallagher et al. 2005] Methods and Experimental Design: Our experiments and testing of a novel UV “Antiradiation Vaccine” have employed a wide variety of laboratory animals which include : Chinchilla

  1. UV radiation hardness of silicon inversion layer solar cells

    International Nuclear Information System (INIS)

    Hezel, R.

    1990-01-01

    For full utilization of the high spectral response of inversion layer solar cells in the very-short-wavelength range of the solar spectrum sufficient ultraviolet-radiation hardness is required. In addition to the charge-induced passivation achieved by cesium incorporation into the silicon nitride AR coating, in this paper the following means for further drastic reduction of UV light-induced effects in inversion layer solar cells without encapsulation are introduced and interpretations are given: increasing the nitride deposition temperature, silicon surface oxidation at low temperatures, and texture etching and using higher substrate resistivities. High UV radiation tolerance and improvement of the cell efficiency could be obtained simultaneously

  2. UV-vis light transmittance through tinted contact lenses and the effect of color on values.

    Science.gov (United States)

    Osuagwu, Uchechukwu L; Ogbuehi, Kelechi C

    2014-06-01

    To assess the transmittance, in the 200-700nm electromagnetic radiation spectrum, by popularly used tinted soft contact lenses (CLs). The spectra transmittances of ultraviolet (UV)-blocking (I Day Acuvue Define, Freshlook ONE DAY) and non-UV-blocking (Durasoft 3, Tutti, and NeoCosmo) tinted soft CLs were tested. The transmittance of each lens, including nine different colors of Freshlook CL was recorded on spectrophotometer, and the data used to also calculate a UV protection factor (PF) for each lens brand tested, with a higher value indicating a higher level of protection. The UV-blocking CLs significantly reduced UVC, UVB & UVA transmission and thereby meet the American National Standards Institution standard for class 2 UV blockers: a maximum of 30% transmittance of UVA and 5% transmittance of UVB wavelengths. In contrast, the Durasoft 3, Tutti, and NeoCosmo CLs demonstrated negligible UV-blockage. The Acuvue Define CL offered the greatest protection from UVC (PF=69) and UVB (PF=55), but with only 35% luminous transmittance, while the Freshlook CL (especially gemstone green) offered the best protection from UVA (PF=24) and showed about 55% translucency. Overall, the UV-blocking CLs performed equally well across the UV spectrum. Different colors of Freshlook CL transmitted statistically and clinically significantly different amounts of visible light but similar amounts of UVR. Freshlook and Acuvue Define CLs which are designated as UV-blockers significantly reduced UVR transmission to safe levels whereas Tutti, NeoCosmo and Durasoft 3 did not. Transmission within the Freshlook CL family was more dependent on color in the visible light spectrum, but not in the UV-spectrum, where the gemstone green performing best among the tested colors. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  3. In vitro photostability and photoprotection studies of a novel 'multi-active' UV-absorber.

    Science.gov (United States)

    Venditti, E; Spadoni, T; Tiano, L; Astolfi, P; Greci, L; Littarru, G P; Damiani, E

    2008-08-01

    This paper reports on the synthesis and properties of a new UV-absorber (OC-NO) based on the most popular UV filter worldwide, ethylhexyl methoxycinnamate (OMC) in which the methoxy group has been replaced with a pyrrolidine nitroxide bearing antioxidant activity. This sunscreen active has therefore both UV-absorbing and antioxidant properties which could ideally address both the UV-B and UV-A skin photo-damage. For broad-spectrum coverage, the combinations of OC-NO with two commonly used UV-A absorbers (BMDBM and DHHB) were also studied. The results obtained reveal that OC-NO: (a) is as photostable as OMC after UV-A exposure; (b) acts as free radical scavenger as demonstrated by EPR and chemical studies; (c) reduces UV-A and UV-A+BMDBM induced lipid peroxidation in liposomes and cells, measured as reduced TBARS levels and increased C11-BODIPY red fluorescence, respectively; (d) has comparable antioxidant activity to that of vitamin E and BHT commonly used in skin care formulations; (e) is non-cytotoxic to human skin fibroblasts as assessed with the MTT assay when exposed to increasing doses of UV-A; and (f) OC-NO+DHHB is a promising, photostable broad spectrum UV-filter combination that concomitantly reduces UV-induced free radical damage. These results suggest that nitroxide/antioxidant-based UV-absorbers may pave the way for the utilization of 'multi-active' ingredients in sunscreens thereby reducing the number of ingredients in these formulations.

  4. UV radiation and its effects. Proceedings

    International Nuclear Information System (INIS)

    1993-01-01

    The National Science Strategy Committee for Climate Change was established in 1991 by the New Zealand Minister of Research, Science and Technology. It advises government through the Minister on research priorities and on levels of expenditure appropriate in various topics relating to climate change. An additional role is to promote coordination between research groups and the user communities to ensure an appropriate range of research strategies. To assist with implementing the latter aspects the NSS Committee will organise workshops on specific aspects of atmosphere and climate change, with a broad spectrum of participants. The first of these was the Workshop on UV Radiation and its Effects held in Christchurch on 20-21 May 1993. The workshop had 40 participants, including representatives from specialist science groups, medicine, veterinary science, farming, forestry and environmental groups. This publication will update the interested reader, whether scientist or lay-person, on the current state of knowledge on changing UV radiation levels and potential problems. As the summaries of papers show, research on ozone levels and on UV radiation and its effects is particularly appropriate for New Zealand scientists with their access to sites covering a wide range of latitudes from Antarctica to the Pacific Islands. New Zealand is part of an important international monitoring network, measuring local stratospheric ozone levels and related surface UV radiation levels. There are concerns about increasing UVB levels and the consequent effects on human health, plant and tree growth, and phytoplankton growth in the oceans. Priorities for further work on these areas are included in the summary of the workshop. (author). 13 figs.; 5 tabs

  5. Design and Fabrication of an Integrated Circuit for Monitoring UV Radiation for Health Physics Applications

    International Nuclear Information System (INIS)

    Nazififard, Mohammad; Faghihi, Reyhaneh; Champiri, Afshin Mahmoudieh; Norov, Enkhbat; Suh, Kune Y.

    2014-01-01

    A particularly important term in the clinical photobiology is the standard erythemal dose (SED), which is a measure of the erythemal effectiveness of a UV exposure. However, both the quality and quantity of the UV radiation are important factors for the UV monitoring. This paper aims to introduce and investigate a UV radiation meter in order to establish its applicability for non-ionizing radiation detection. The ultraviolet (UV) radiation is part of the electromagnetic spectrum. The biological effects of UV radiation vary enormously with wavelength and for this reason the UV spectrum is further divided into three regions: UVA, UVB, and UVC. There is increasing evidence that long wave UV radiation plays a vital role in the pathogenesis of photo-dermatoses such as polymorphous light eruption as well as photo-aging. UVA, UVB, and UVC can all damage collagen fibers and, therefore, accelerate aging of the skin. Both UVA and UVB destroy vitamin A in the skin, which may cause further damage. The quantities of the UV radiation are generally expressed using the radiometric terminology

  6. Design and Fabrication of an Integrated Circuit for Monitoring UV Radiation for Health Physics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nazififard, Mohammad; Faghihi, Reyhaneh [Kashan Univ., Kashan (Iran, Islamic Republic of); Champiri, Afshin Mahmoudieh [Shahid Chamran Univ., Ahwaz (Iran, Islamic Republic of); Norov, Enkhbat [POSTECH, Pohang (Korea, Republic of); Suh, Kune Y. [Seoul National Univ., Seoul (Korea, Republic of)

    2014-05-15

    A particularly important term in the clinical photobiology is the standard erythemal dose (SED), which is a measure of the erythemal effectiveness of a UV exposure. However, both the quality and quantity of the UV radiation are important factors for the UV monitoring. This paper aims to introduce and investigate a UV radiation meter in order to establish its applicability for non-ionizing radiation detection. The ultraviolet (UV) radiation is part of the electromagnetic spectrum. The biological effects of UV radiation vary enormously with wavelength and for this reason the UV spectrum is further divided into three regions: UVA, UVB, and UVC. There is increasing evidence that long wave UV radiation plays a vital role in the pathogenesis of photo-dermatoses such as polymorphous light eruption as well as photo-aging. UVA, UVB, and UVC can all damage collagen fibers and, therefore, accelerate aging of the skin. Both UVA and UVB destroy vitamin A in the skin, which may cause further damage. The quantities of the UV radiation are generally expressed using the radiometric terminology.

  7. Uvs Nuur, Mongolia

    Science.gov (United States)

    2007-01-01

    The Uvs Nuur Basin in Mongolia and the Russian Federation is the northernmost of the enclosed basins of Central Asia. It takes its name from Uvs Nuur Lake, a large, shallow and very saline lake, very important for migrating birds. Inscribed as a UNESCO World Heritage Site in 2003, the site is made up of twelve protected areas representing major biomes of eastern Eurasia. The steppe ecosystem supports a rich diversity of birds and the desert is home to a number of rare gerbil, jerboas and the marbled polecat. The mountains are an important refuge for the endangered snow leopard, mountain sheep, and the Asiatic ibex. The image covers an area of 46 x 47.8 km, was acquired on September 4, 2001, and is located near 50.3 degrees north latitude, 90.7 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  8. CUVE - Cubesat UV Experiment: Unveil Venus' UV Absorber with Cubesat UV Mapping Spectrometer

    Science.gov (United States)

    Cottini, V.; Aslam, S.; D'Aversa, E.; Glaze, L.; Gorius, N.; Hewagama, T.; Ignatiev, N.; Piccioni, G.

    2017-09-01

    Our Venus mission concept Cubesat UV Experiment (CUVE) is one of ten proposals selected for funding by the NASA PSDS3 Program - Planetary Science Deep Space SmallSat Studies. CUVE concept is to insert a CubeSat spacecraft into a Venusian orbit and perform remote sensing of the UV spectral region using a high spectral resolution point spectrometer to resolve UV molecular bands, observe nightglow, and characterize the unidentified main UV absorber. The UV spectrometer is complemented by an imaging UV camera with multiple bands in the UV absorber main band range for contextual imaging. CUVE Science Objectives are: the nature of the "Unknown" UV-absorber; the abundances and distributions of SO2 and SO at and above Venus's cloud tops and their correlation with the UV absorber; the atmospheric dynamics at the cloud tops, structure of upper clouds and wind measurements from cloud-tracking; the nightglow emissions: NO, CO, O2. This mission will therefore be an excellent platform to study Venus' cloud top atmospheric properties where the UV absorption drives the planet's energy balance. CUVE would complement past, current and future Venus missions with conventional spacecraft, and address critical science questions cost effectively.

  9. Spectrum 101: An Introduction to Spectrum Management

    Science.gov (United States)

    2004-03-01

    produces a Joint Restricted Frequency List (JRFL). The JFRL consolidates and classifies the spectrum uses that are most critical to operations and to...Management Office JRFL Joint Restricted Frequency List JSC Joint Spectrum Center JSIR Joint Spectrum Interference Resolution JSME Joint Spectrum...Multifunctional Information Distribution System MILSATCOM Military Satellite Communications MOA Memorandum of Agreement MRFL Master Radio Frequency

  10. Flavonols Protect Against UV Radiation-Induced Thymine Dimer Formation in an Artificial Skin Mimic.

    Science.gov (United States)

    Maini, Sabia; Fahlman, Brian M; Krol, Ed S

    2015-01-01

    Exposure of skin to ultraviolet light has been shown to have a number of deleterious effects including photoaging, photoimmunosuppression and photoinduced DNA damage which can lead to the development of skin cancer. In this paper we present a study on the ability of three flavonols to protect EpiDerm™, an artificial skin mimic, against UV-induced damage. EpiDerm™ samples were treated with flavonol in acetone and exposed to UVA (100 kJ/m(2) at 365 nm) and UVB (9000 J/m(2) at 310 nm) radiation. Secretion of matrix metalloproteinase-1 (MMP-1) and tumor necrosis factor-α (TNF-a) were determined by ELISA, cyclobutane pyrimidine dimers were quantified using LC-APCI-MS. EpiDerm™ treated topically with quercetin significantly decreased MMP-1 secretion induced by UVA (100 µM) or UVB (200 µM) and TNF-a secretion was significantly reduced at 100 µM quercetin for both UVA and UVB radiation. In addition, topically applied quercetin was found to be photostable over the duration of the experiment. EpiDerm™ samples were treated topically with quercetin, kaempferol or galangin (52 µM) immediately prior to UVA or UVB exposure, and the cyclobutane thymine dimers (T-T (CPD)) were quantified using an HPLC-APCI MS/MS method. All three flavonols significantly decreased T-T (CPD) formation in UVB irradiated EpiDerm™, however no effect could be observed for the UVA irradiation experiments as thymine dimer formation was below the limit of quantitation. Our results suggest that flavonols can provide protection against UV radiation-induced skin damage through both antioxidant activity and direct photo-absorption. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  11. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita

    2016-03-01

    Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

  12. Study of kinetics of the tetroxane thermolysis by UV spectrophotometry

    International Nuclear Information System (INIS)

    Jorge, N.L.; Leiva, L.C.; Castellanos, M.G.; Cafferata, L.F.R.; Gomez V, M.E.

    2002-01-01

    The 3,3,6,6-tetramethyl-1,2,4,5-tetroxane (ACDP) in methanol solution shows an absorbance peak at low wave length in UV spectrum and follows the Lambert Beer law until 10-2 M concentration at 209 nm. The ACDP thermal decomposition have been studied by the UV spectroscopy like an alternative method to find out the kinetic parameters from the thermolysis of these compounds. The rate constants at the temperatures and initial concentration ranges of 130-166 and 0,003-0,013 mol / L, respectively, and the activation parameters were similar to the corresponding values found by other methodology, verifying this analytic technique. Acetone produced during reaction no interference in ACDP quantification by UV analysis. (Author)

  13. Plant's adaptive response under UV-B-radiation influence

    International Nuclear Information System (INIS)

    Danil'chenko, O.A.; Grodzinskij, D.M.

    2002-01-01

    Reduction of ozone layer, owing to anthropogenic contamination of an atmosphere results in increase of intensity of UV-radiation and shift of its spectrum in the short-wave side that causes strengthening of various biological effects of irradiation. Consequences of these processes may include increase of injuring of plants and decrease of productivity of agricultural crops to increased UV levels. The important significance in the plant's adaptation to different unfavorable factors has the plant's radioadaptive answer. It has been shown that radioadaptation of plants occurred not only after irradiation with g-radiation in low doses but after UV-rays action . Reaction of radioadaptation it seems to be nonspecific phenomenon in relation to type radiations

  14. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    Energy Technology Data Exchange (ETDEWEB)

    Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Barman, Travis S., E-mail: shkolnik@lowell.edu, E-mail: barman@lpl.arizona.edu [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2014-10-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t {sup –1}. Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  15. HAZMAT. I. The evolution of far-UV and near-UV emission from early M stars

    International Nuclear Information System (INIS)

    Shkolnik, Evgenya L.; Barman, Travis S.

    2014-01-01

    The spectral energy distribution, variability, and evolution of the high-energy radiation from an M dwarf planet host is crucial in understanding the planet's atmospheric evolution and habitability and in interpreting the planet's spectrum. The star's extreme-UV (EUV), far-UV (FUV), and near-UV (NUV) emission can chemically modify, ionize, and erode the atmosphere over time. This makes determining the lifetime exposure of such planets to stellar UV radiation critical for both the evolution of a planet's atmosphere and our potential to characterize it. Using the early M star members of nearby young moving groups, which sample critical ages in planet formation and evolution, we measure the evolution of the GALEX NUV and FUV flux as a function of age. The median UV flux remains at a 'saturated' level for a few hundred million years, analogous to that observed for X-ray emission. By the age of the Hyades Cluster (650 Myr), we measure a drop in UV flux by a factor of 2-3 followed by a steep drop from old (several Gyrs) field stars. This decline in activity beyond 300 Myr follows roughly t –1 . Despite this clear evolution, there remains a wide range, of 1-2 orders of magnitude, in observed emission levels at every age. These UV data supply the much-needed constraints to M dwarf upper-atmosphere models, which will provide empirically motivated EUV predictions and more accurate age-dependent UV spectra as inputs to planetary photochemical models.

  16. UV imaging in pharmaceutical analysis

    DEFF Research Database (Denmark)

    Østergaard, Jesper

    2018-01-01

    UV imaging provides spatially and temporally resolved absorbance measurements, which are highly useful in pharmaceutical analysis. Commercial UV imaging instrumentation was originally developed as a detector for separation sciences, but the main use is in the area of in vitro dissolution...

  17. Calibration of UV instruments and limitations on accuracy

    International Nuclear Information System (INIS)

    Clare, J.F.; Hamlin, J.D.

    1993-01-01

    Instruments measuring UV radiation may be classified as either spectrometers or broadband monitors; whilst the former determine irradiance as a function of wavelength the latter measure a summation of spectral irradiance weighted by some instrument response function which may be designed to approximate a desired action spectrum. For both classes a proper calibration requires the determination of the instrument's absolute spectral responsivity across the relevant wave-band together with an adequate determination of the wavelengths involved. (author). 7 refs

  18. The mechanisms of UV mutagenesis

    International Nuclear Information System (INIS)

    Ikehata, Hironobu; Ono, Tetsuya

    2011-01-01

    Ultraviolet (UV) light induces specific mutations in the cellular and skin genome such as UV-signature and triplet mutations, the mechanism of which has been thought to involve translesion DNA synthesis (TLS) over UV-induced DNA base damage. Two models have been proposed: ''error-free'' bypass of deaminated cytosine-containing cyclobutane pyrimidine dimers (CPDs) by DNA polymerase η, and error-prone bypass of CPDs and other UV-induced photolesions by combinations of TLS and replicative DNA polymerases-the latter model has also been known as the two-step model, in which the cooperation of two (or more) DNA polymerases as misinserters and (mis)extenders is assumed. Daylight UV induces a characteristic UV-specific mutation, a UV-signature mutation occurring preferentially at methyl-CpG sites, which is also observed frequently after exposure to either UVB or UVA, but not to UVC. The wavelengths relevant to the mutation are so consistent with the composition of daylight UV that the mutation is called solar-UV signature, highlighting the importance of this type of mutation for creatures with the cytosine-methylated genome that are exposed to the sun in the natural environment. UVA has also been suggested to induce oxidative types of mutation, which would be caused by oxidative DNA damage produced through the oxidative stress after the irradiation. Indeed, UVA produces oxidative DNA damage not only in cells but also in skin, which, however, does not seem sufficient to induce mutations in the normal skin genome. In contrast, it has been demonstrated that UVA exclusively induces the solar-UV signature mutations in vivo through CPD formation. (author)

  19. Deep UV LEDs

    Science.gov (United States)

    Han, Jung; Amano, Hiroshi; Schowalter, Leo

    2014-06-01

    Deep ultraviolet (DUV) photons interact strongly with a broad range of chemical and biological molecules; compact DUV light sources could enable a wide range of applications in chemi/bio-sensing, sterilization, agriculture, and industrial curing. The much shorter wavelength also results in useful characteristics related to optical diffraction (for lithography) and scattering (non-line-of-sight communication). The family of III-N (AlGaInN) compound semiconductors offers a tunable energy gap from infrared to DUV. While InGaN-based blue light emitters have been the primary focus for the obvious application of solid state lighting, there is a growing interest in the development of efficient UV and DUV light-emitting devices. In the past few years we have witnessed an increasing investment from both government and industry sectors to further the state of DUV light-emitting devices. The contributions in Semiconductor Science and Technology 's special issue on DUV devices provide an up-to-date snapshot covering many relevant topics in this field. Given the expected importance of bulk AlN substrate in DUV technology, we are pleased to include a review article by Hartmann et al on the growth of AlN bulk crystal by physical vapour transport. The issue of polarization field within the deep ultraviolet LEDs is examined in the article by Braut et al. Several commercial companies provide useful updates in their development of DUV emitters, including Nichia (Fujioka et al ), Nitride Semiconductors (Muramoto et al ) and Sensor Electronic Technology (Shatalov et al ). We believe these articles will provide an excellent overview of the state of technology. The growth of AlGaN heterostructures by molecular beam epitaxy, in contrast to the common organo-metallic vapour phase epitaxy, is discussed by Ivanov et al. Since hexagonal boron nitride (BN) has received much attention as both a UV and a two-dimensional electronic material, we believe it serves readers well to include the

  20. Total photoabsorption cross section on nuclei measured in energy range 0.5-2.6 GeV; Misura della sezione d`urto di fotoassorbimento tra 0.5 e 2.6 GeV su nuclei ed analisi dei dati

    Energy Technology Data Exchange (ETDEWEB)

    Mirazita, M. [INFN, Laboratori Nazionali di Frascati, Rome (Italy)

    1998-03-01

    The total photoabsorption cross section on several nuclei has been measured in the energy range 0.5 - 2.6 GeV. Nuclear data show a significant reduction of the absorption strength with respect to the free nucleon case suggesting a shadowing effect at low energies.

  1. Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers

    International Nuclear Information System (INIS)

    Mazzillo, M.; Renna, L.; Costa, N.; Badalà, P.; Sciuto, A.; Mannino, G.

    2016-01-01

    Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. The sun is our primary natural source of UV radiation. The strength of the sun's ultraviolet radiation is expressed as Solar UV Index (UVI). UV-A (320–400 nm) and UV-B (290–320 nm) rays mostly contribute to UVI. UV-B is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA. Also overexposure to UV-A rays, although these are less energetic than UV-B photons, has been associated with toughening of the skin, suppression of the immune system, and cataract formation. The use of preventive measures to decrease sunlight UV radiation absorption is fundamental to reduce acute and irreversible health diseases to skin, eyes and immune system. In this perspective UV sensors able to monitor in a monolithic and compact chip the UV Index and relative UV-A and UV-B components of solar spectrum can play a relevant role for prevention, especially in view of the integration of these detectors in close at hand portable devices. Here we present the preliminary results obtained on our UV-A sensor technology based on the use of hydrogenated Silicon Nitride (SiN:H) thin passivating layers deposited on the surface of thin continuous metal film Ni 2 Si/4H-SiC Schottky detectors, already used for UV-Index monitoring. The first UV-A detector prototypes exhibit a very low leakage current density of about 0.2 pA/mm 2 and a peak responsivity value of 0.027 A/W at 330 nm, both measured at 0V bias.

  2. Synthesis and characterization of UV-absorbing fluorine-silicone acrylic resin polymer

    Science.gov (United States)

    Lei, Huibin; He, Deliang; Guo, Yanni; Tang, Yining; Huang, Houqiang

    2018-06-01

    A series of UV-absorbing fluorine-silicone acrylic resin polymers containing different amount of UV-absorbent were successfully prepared by solution polymerization, with 2-[3-(2H-Benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate (BHEM), vinyltrimethoxysilane (VTMS) and hexafluorobutyl methacrylate (HFMA) as modifying monomers. The acrylic polymers and the coatings thereof were characterized by Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) absorption spectrum, thermogravimetric analysis (TGA), water contact angle (CA) and Xenon lamp artificial accelerated aging tests. Results indicated that the resin exhibited high UV absorption performance as well as good thermal stability. The hydrophobicity of the coatings was of great improvement because of the bonded fluorine and silicone. Meanwhile, the weather-resistance was promoted through preferably colligating the protective effects of BHEM, organic fluorine and silicone. Also, a fitting formula about the weatherability with the BMHE content was tentatively proposed.

  3. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  4. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Leer en Español: El ... Aug. 28, 2014 Keep an Eye on Ultraviolet (UV) Safety Eye medical doctors (ophthalmologists) caution us that ...

  5. UV-induced skin damage

    International Nuclear Information System (INIS)

    Ichihashi, M.; Ueda, M.; Budiyanto, A.; Bito, T.; Oka, M.; Fukunaga, M.; Tsuru, K.; Horikawa, T.

    2003-01-01

    Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies suggest that solar UV radiation is responsible for skin tumor development via gene mutations and immunosuppression, and possibly for photoaging. In this review, recent understanding of DNA damage caused by direct UV radiation and by indirect stress via reactive oxygen species (ROS) and DNA repair mechanisms, particularly nucleotide excision repair of human cells, are discussed. In addition, mutations induced by solar UV radiation in p53, ras and patched genes of non-melanoma skin cancer cells, and the role of ROS as both a promoter in UV-carcinogenesis and an inducer of UV-apoptosis, are described based primarily on the findings reported during the last decade. Furthermore, the effect of UV on immunological reaction in the skin is discussed. Finally, possible prevention of UV-induced skin cancer by feeding or topical use of antioxidants, such as polyphenols, vitamin C, and vitamin E, is discussed

  6. UV survival of human mycoplasmas

    International Nuclear Information System (INIS)

    Aoki, Shigeji; Ito, Shoko; Watanabe, Takehiko

    1979-01-01

    The inactivation by ultraviolet (UV) light irradiation of mycoplasma cells of five human strains was monitored by investigating the colony-forming ability. The survival curves of five strains tested indicated that the cells of Mycoplasma buccale only are single and homogenously susceptible to UV light. The effect of the repair inhibitor, caffeine, on the colony-forming ability of UV-irradiated cells was investigated with M. buccale because of its homogeneous susceptibility to UV light. The colony formation of irradiated cells was markedly depressed by post-irradiation treatment with caffeine at concentration that had little or no effect on the colony formation of unirradiated cells. The colony-forming units (CFU) of UV-irradiated cells which were kept in broth without caffeine in the dark increased without a lag as the time in the dark increased. The colony-forming ability of the irradiated cells completely recovered after 3 hr in the dark. However, when irradiated cells were kept in the presence of caffeine, no increase in their CFU was observed. The mode of action of caffeine on UV-irradiated cells closely resembles that described for other organisms which possess dark reactivation systems for UV-induced damage in deoxyribonucleic acid. Thus, the results obtained provide evidence for the existence of a dark repair function in M. buccale. (author)

  7. Aerosol effects on UV radiation

    International Nuclear Information System (INIS)

    Koepke, P.; Reuder, J.; Schwander, H.

    2000-01-01

    The reduction of erythemally weighted UV-irradiance (given as UV index, UVI) due to aerosols is analyzed by variation of the tropospheric particles in a wide, but realistic range. Varied are amount and composition of the particles and relative humidity and thickness of the mixing layer. The reduction of UVI increases with aerosol optical depth and the UV change is around 10% for a change aerosol optical depth from 0.25 to 0.1 and 0.4 respectively. Since both aerosol absorption and scattering are of relevance, the aerosol effect depends besides total aerosol amount on relative amount of soot and on relative humidity

  8. New horizons for Supercontinuum light sources: from UV to mid-IR

    DEFF Research Database (Denmark)

    Thomsen, Carsten L.; Nielsen, Frederik Donbæk; Johansen, Jeppe

    2013-01-01

    Commercially available supercontinuum sources continue to experience a strong growth in a wide range of industrial and scientific applications. In addition, there is a significant research effort focused on extending the wavelength coverage both towards UV and Mid-IR. Broadband sources covering...... and novel pumping schemes, whereas shifting the spectrum further towards the UV has been based on sophisticated microstructure fiber designs. Here we present our latest developments in tailoring the power and spectral coverage of spatially coherent broadband supercontinuum sources....

  9. Medical UV exposures and HIV activation

    International Nuclear Information System (INIS)

    Zmudzka, B.Z.; Miller, S.A.; Jacobs, M.E.; Beer, J.Z.

    1996-01-01

    This paper presents the first attempt to evaluate the potential of clinical UV exposures to induce the human immunodeficiency (HIV) promoter and, thus, to upregulate HIV growth in those skin cells that are directly affected by the exposure. Using the data for HIV promoter activation in vitro, we computed UVB and psoralen plus UVA (PUVA) doses that produce 50% of the maximal promoter activation (AD 50 ). Then, using (a) literature data for UV transmittance in the human skin, (b) a composite action spectrum for HIV promoter and pyrimidine dimer induction by UVB and (c) an action spectrum for DNA synthesis inhibition by PUVA, we estimated the distribution of medical UVB and PUVA doses in the skin. This allowed us to estimate how deep into the skin the HIV-activating doses might penetrate in an initial and an advanced stge of UVB and PUVA therapy. Such analysis was done for normal type II skin and for single exposures. For UVB we found that, when the incident dose on the surface of the skin is 500 J/m 2 (290-320 nm) (initial stage of the therapy), the dose producing 50% of the maximal HIV promoter activation (AD 50 UVB ) is limited to the stratum corneum. For PUVA we found that, when the incident UVA doses are 25 or 100 kJ/m 2 (320-400 nm) (an initial and an advanced stage of therapy, respectively), and the 8-methoxypsoralen concentration in the blood is 0.1 μg/mL (the desired level), the combined doses to the mid epidermis (and some areas of the upper dermis) are well below the 50% HIV promoter-activating PUVA dose (AD 50 PUVA ). These results suggest that the probability of HIV activation in the epidermis by direct mechanisms is higher for UVB than for PUVA treatment. However, complexities of the UV-inducible HIV activation and immunomodulatory phenomena are such that our results by themselves should not be taken as an indication that UVB therapy carries a high risk than PUVA therapy when administered to HIV-infected patients. (Author)

  10. UV/EB curable psa's

    International Nuclear Information System (INIS)

    Glotfelter, C.A.

    1995-01-01

    The author describe both water-based and 100% solids UV/EB curable PSA's (Pressure Sensitive Adhesives) and their properties. A new acrylate monomer, ethoxylated nonyl phenol acrylate, has great utility in the formulation of water-based PSA's

  11. Multiple UV reflectance peaks in the iridescent neck feathers of pigeons

    Science.gov (United States)

    McGraw, Kevin J.

    Recent studies of colorful plumage signals in birds have been aided by the finding that birds can see ultraviolet (UV) light and thus may communicate using colors invisible to humans. Some of the pioneering and more pivotal work on avian color vision was performed with domestic pigeons (Columba livia), yet surprisingly there have been few detailed reports of the UV-reflecting properties of pigeon feathers. Here, I use UV-VIS fiber-optic spectrometry to document the full-spectrum reflectance characteristics of iridescent purple and green neck plumage in pigeons. Neck feathers that appear purple to the human eye exhibit four reflectance peaks-two in the UV and one in the blue and red regions-and thus exhibit a UV-purple hue. Neck feathers that appear green to the human eye are characterized by five spectral peaks: two in the UV (UVA and UVB), a predominant green peak, and secondary violet and red peaks, conferring a UV-purple-green color. Such elaborate UV coloration suggests that birds may use an even more complex and `hidden' UV signaling system than previously thought.

  12. UV absorption spectrum of CH3OCH2 radicals and kinetics of the reaction of CH3OCH2O2 radicals with NO and NO2 in the gas phase

    DEFF Research Database (Denmark)

    Langer, S.; Ljungström, E.; Ellermann, T.

    1995-01-01

    Alkyl and alkylperoxy radicals originating from dimethyl ether have been studied in the gas phase at 296 K. A pulse radiolysis-UV absorption technique was used. Absorption cross-sections were quantified over the wavelength range 220-350 nm. At 230 nm, sigma(CH3OCH2) = (4.2 +/- 0.5) X 10(-18) cm(2...

  13. Influence of the Halogen Ligand on the Near UV/Visible Spectrum of [Ru(X) (Me)(CO)2(alpha-diimine)] (X=Cl, I; alpha-diimine=Me-DAB, iPr-DAB; DAB=1,4-diaza-1,3-butadiene): An ab initio and TD-DFT Analysis

    Czech Academy of Sciences Publication Activity Database

    Záliš, Stanislav; Amor, N. B.; Daniel, C.

    2004-01-01

    Roč. 43, - (2004), s. 7978-7985 ISSN 0020-1669 R&D Projects: GA MŠk 1P04OCD14.20 Institutional research plan: CEZ:AV0Z4040901 Keywords : halogen ligand * TD-DFT analysis * UV-vis electronic spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.454, year: 2004

  14. Spectrum estimation method based on marginal spectrum

    International Nuclear Information System (INIS)

    Cai Jianhua; Hu Weiwen; Wang Xianchun

    2011-01-01

    FFT method can not meet the basic requirements of power spectrum for non-stationary signal and short signal. A new spectrum estimation method based on marginal spectrum from Hilbert-Huang transform (HHT) was proposed. The procession of obtaining marginal spectrum in HHT method was given and the linear property of marginal spectrum was demonstrated. Compared with the FFT method, the physical meaning and the frequency resolution of marginal spectrum were further analyzed. Then the Hilbert spectrum estimation algorithm was discussed in detail, and the simulation results were given at last. The theory and simulation shows that under the condition of short data signal and non-stationary signal, the frequency resolution and estimation precision of HHT method is better than that of FFT method. (authors)

  15. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  16. DNA damage caused by UV- and near UV-irradiation

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1986-01-01

    Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

  17. Two-components UV-therapy

    International Nuclear Information System (INIS)

    Pullmann, H.; Steigleder, G.K.

    1980-01-01

    20 patients with generalized psoriasis were treated with an apparatus containing UV-A- and UV-B-fluorescence tubes to be switched separately. The therapy was started with an UV-A-dose of 12 J/cm 2 daily. After the first week of treatment UV-B in increasing doses was applicated additionally. Clearance was achieved in 80 percent. (orig.) [de

  18. Quantification of naphazoline nitrate by UV-spectrophoto-metry

    Directory of Open Access Journals (Sweden)

    O. I. Panasenko

    2013-12-01

    Full Text Available One of the main tasks of pharmaceutical chemistry – medical drugs study. Spectrophotometry is widely used in studying of the structure and composition (complexes, dyes, analytical reagents, etc. of various compounds. It widely used for qualitative and quantitative determination of substances (determination of elements traces in metals, alloys, technical facilities. The dependence between substance structure and its electronic spectrum is being studied by many researchers till nowadays. The aim of this work was to highlight the issues of naphazoline quantify definition techniques by the UV-spectrophotometry. According to the existing methods of quality control (MQC, naphazoline nitrate is a substance quantitatively determined by acid-base titration among a mixture of anhydrous acetic acid and acetic anhydride. Titration is carried out with a solution of 0,1 M perchloric acid (indicator - crystal violet. To check the quality of nasal drops nafazoline nitrate MQC is recommended UV-spectrophotometry: drug is dissolved in boric acid solution (20 g/l as the reference solution used solution pharmacopoeia standard sample substance nafazoline nitrate. The character of UV-spectra of the nafazoline nitrate in solvents of different polarity (water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl, 5M H2SO4, was defined and studied. Standard sample of nafazoline nitrate was obtained from the State Enterprise "Scientific and Expert Pharmacopoeia Centre Ukraine". In order to study UV-spectra nafazoline nitrate spectrophotometer SPECORD 200-222U214 (Germany was used. UV-spectrum of nafazoline nitrate in water and 95% ethanol are characterized by two maxima at 270 and 280 nm. Absorption band of nafazoline nitrate in 0, 1 M sodium hydroxide has two maxima at 271 and 280 nm, and in 0, 1 M solution of hydrochloric acid and 5 M solution of sulfuric acid maxima coincide with the maxima spectrum of the drug in water, 95% ethanol. In order to avoid errors associated with

  19. Large area UV light source with a semiconductor cathode

    International Nuclear Information System (INIS)

    Salamov, B. G.; Ciftci, Y. Oe.; Colakoglu, K.

    2002-01-01

    The light emission (LE) in the UV and visible (blue) range generated by a planar gas discharge system (PGDS) with a semiconductor cathode (SC) are studied. New light source offer high-intensity narrow-band emission at various UV and visible wavelengths (330 - 440 nm). Spectra in N 2 is presented, as well as intensity vs pressure curves for the main peaks of the spectrum. The use of source offers several advantages: PGDS can be extremely efficient energy converters transforming and amplifying a relatively low-powered photon flux incident on the receiving surface of the SC into a flux of high-energy particles over extended areas, i.e. electron, ions, photons. Thus, extremely bright UV and visible sources can be built. LE characteristics of the space in the PGDS are complex, depending on the emitting medium and species. By using the IR light to excite the SC of the system, we have shown that the discharge light emission (DLE) of the device with the N 2 in the gap can serve as an efficient source of the UV radiation if gas pressure and electric field are sufficiently high. This is realized due to the effect of the stabilisation of the spatially homogeneous mode of the discharge in a narrow gap with a large emitting area of SC. Special features of DLE render it highly promising for the development of sources with a large area of the emitting surface, high spatial uniformity of UV radiation, and fast dynamics of these devices. This low cost, high power light sources can provide an interesting alternative to conventional UV lamps

  20. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    Mehnert, R.

    1999-01-01

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

  1. UV-indeks og dets betydning

    DEFF Research Database (Denmark)

    Wulf, Hans Christian; Eriksen, Paul

    2010-01-01

    The published UV index refers to the expected UV intensity at mid day, when the solar elevation is at its maximum. In Scandinavia, the maximum UV index is seven around midsummer. When the UV index is three, the erythema-weighted dose will be three Standard Erythema Dose (SED) in the hour with max...... a sunburn already when the UV index is higher than two....

  2. UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report

    International Nuclear Information System (INIS)

    Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

    2012-01-01

    radiation or by sunbed UV lamps. All studies of the project (240 volunteers) were structured concerning UV skin type II and III, age and sex. In addition, data on the natural skin protection of the volunteers against UV radiation were measured in order to evaluate possible correlations between individual UV sensitivity and the efficiency of vitamin D synthesis. In result: In winter time, before starting the studies, the mean 25OH-vitamin D serum level of 18 ng/ml of the volunteers was in the deficiency range (< 20 ng/ml). UV exposures of 10 % MED applied twice a week vertically to face and hands caused significant increases of the 25OH-vitamin D serum level. The increase rised with higher UV doses and/or larger skin area exposed to UV radiation of the solar summer spectrum. While the increase of the 25OHvitamin D serum level in the UV cabinet was roughly independent from the basic level, under solar exposure conditions there were distinct variations between subjects as well as different outcomes for the whole group, which possibly depended on low outdoor temperatures during the solar exposures. Exposures by sunbed UV lamps lead to decreasing efficiencies in vitamin D production. An increase of the biologically effective UV dose and/or of the UV-exposed skin area decreased the vitamin D efficiency down to 30 % compared to simulated solar radiation. Because of strong differences in UV erythema sensitivity of the skin of different anatomical locations, we hypothesized similar relations in the efficiency of UV-induced vitamin D synthesis. The efficiency of UV-induced vitamin D synthesis varies up to 400 % between the anatomical locations of the body. The investigation of the content of provitamin D (7-Dehydrocholesterol), the source of the vitamin D synthesis in the skin, and of the influence of UV exposure on the level of this content results in new findings, too. Suberythemal UV exposures do not influence the 7-DHC-concentration in the skin. 1 MED leads to a significant

  3. A critical assessment of two types of personal UV dosimeters.

    Science.gov (United States)

    Seckmeyer, Gunther; Klingebiel, Marcus; Riechelmann, Stefan; Lohse, Insa; McKenzie, Richard L; Liley, J Ben; Allen, Martin W; Siani, Anna-Maria; Casale, Giuseppe R

    2012-01-01

    Doses of erythemally weighted irradiances derived from polysulphone (PS) and electronic ultraviolet (EUV) dosimeters have been compared with measurements obtained using a reference spectroradiometer. PS dosimeters showed mean absolute deviations of 26% with a maximum deviation of 44%, the calibrated EUV dosimeters showed mean absolute deviations of 15% (maximum 33%) around noon during several test days in the northern hemisphere autumn. In the case of EUV dosimeters, measurements with various cut-off filters showed that part of the deviation from the CIE erythema action spectrum was due to a small, but significant sensitivity to visible radiation that varies between devices and which may be avoided by careful preselection. Usually the method of calibrating UV sensors by direct comparison to a reference instrument leads to reliable results. However, in some circumstances the quality of measurements made with simple sensors may be over-estimated. In the extreme case, a simple pyranometer can be used as a UV instrument, providing acceptable results for cloudless skies, but very poor results under cloudy conditions. It is concluded that while UV dosimeters are useful for their design purpose, namely to estimate personal UV exposures, they should not be regarded as an inexpensive replacement for meteorological grade instruments. © 2011 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

  4. Antibodies to uv light denatured DNA in systemic lupus erythematosus: detection by filter radioimmunoassay and clinical correlations

    Energy Technology Data Exchange (ETDEWEB)

    Davis, P; Russell, A S; Percy, J S

    1976-12-01

    Antibodies to ultraviolet light denatured DNA (UV DNA) have been measured in patients with systemic lupus erythematosus (SLE) and normal subjects, using a millipore filter radioimmunoassay. High levels of UV DNA binding were only found in patients with SLE. The presence of UV DNA antibodies correlated well with the presence of native DNA antibodies, although immunodiffusion studies and inhibition techniques showed these antibodies to be immunologically distinct in many cases. Forty-one percent of the SLE patients had had photosensitivity at some stage of their disease, but there was a poor correlation between this symptom and the presence of UV DNA antibodies. Although UV DNA is known to be a potent immunogen, none of the results from this study suggests that antibodies to UV DNA are more than another example of the broad spectrum of antinuclear antibodies seen in SLE.

  5. Biological UV-doses and the effect on an ozone layer depletion

    International Nuclear Information System (INIS)

    Dahlback, A.; Henriksen, T.

    1988-08-01

    Effective UV-doses were calculated based on the integrated product of the biological action spectrum and the solar radiation. The calculations included absorption and scattering of UV-radiation in the atmosphere, both for normal ozone conditions as well as for a depleted ozone layer. The effective annual UV-dose increases by approximately 4% per degree of latitude towards the equator. An ozone depletion of 1% increases the annual UV-dose by approximately 1% at 60 o N. A large depletion of 50% over Scandinavia (60 o N) would give this region an effective UV-dose similar to that obtained, with normal ozone conditions, at a latitude of 40 o N (California or the Mediterranean countries). The Antarctic ozone hole increases the annual UV-dose by 20 to 25% which is a similar increase as that attained by moving 5 to 6 degrees of latitude nearer the equator. The annual UV-dose on higher latitudes is mainly determined by the summer values of ozone. Both the ozone values and the effective UV-doses vary from one year to another (within ±4%). No positive or negative trend is observed for Scandinavia from 1978 to 1988

  6. Fundamental Questions in Astrophysics: Guidelines for Future UV Observatories

    CERN Document Server

    Gómez de Castro, Ana I

    2006-01-01

    Modern astrophysics is a mature science that has evolved from its early phase of discovery and classification to a physics-oriented discipline focused in finding answers to fundamental problems ranging from cosmology to the origin and diversity of life-sustainable systems in the Universe. For this very reason, progress of modern astrophysics requires the access to the electromagnetic spectrum in the broadest energy range. The Ultraviolet is a fundamental energy domain since it is one of the most powerful tool to study plasmas at temperatures in the 3,000-300,000~K range as well as electronic transitions of the most abundant molecules in the Universe. Moreover, the UV radiation field is a powerful astrochemical and photoionizing agent. This book describes the fundamental problems in modern astrophysics that cannot progress without easy and wide-spread access to modern UV instrumentation.

  7. From UV/IR mixing to closed strings

    International Nuclear Information System (INIS)

    Lopez, Esperanza

    2003-01-01

    It was shown in [1] that the leading UV/IR mixing effects in noncommutative gauge theories on D-branes are able to capture information about the closed string spectrum of the parent string theory. The analysis was carried out for D-branes on nonsupersymmetric C 3 /Z N orbifolds of Type IIB. In this paper we consider D-branes on twisted circles compactifications of Type II string theory. We find that the signs of the leading UV/IR mixing effects know about the (mass) 2 gap between the lowest modes in NSNS and RR closed string towers. Moreover, the relevant piece of the field theory effective action can be reproduced purely in the language of closed strings. Remarkably, this approach unifies in a single structure, that of a closed string exchange between D-branes, both the leading planar and nonplanar effects associated to the absence of supersymmetry. (author)

  8. EPR and UV spectrometry investigation of sucrose irradiated with carbon particles

    International Nuclear Information System (INIS)

    Karakirova, Yordanka; Yordanov, Nicola D.

    2010-01-01

    Solid state/EPR (SS/EPR) dosimeters of carbon ions irradiated sucrose are studied with EPR, and their water solutions - with UV spectroscopy. Doses between 20 and 200 Gy are used with linear energy transfer (LET) values for carbon ions of 63, 77, 96 and 230 keV μm -1 . After irradiation all samples show typical for irradiated sucrose EPR and UV spectra. The obtained data are compared with those previously reported for nitrogen particles and gamma rays irradiated sucrose. The identical shape of both the EPR and UV spectra of irradiated with various type radiation samples suggests that generated free radicals are not influenced by the nature of radiation. The lack of difference in the line width of the separate lines or the whole EPR spectrum, obtained for gamma and heavy particles irradiation, suggests negligible spin-spin interaction among the radiation-generated free radicals in the samples. The linear dependence of the EPR response on the absorbed dose radiation is found to be higher when generated by gamma rays, than by the same absorbed dose of heavy particles. In addition, the EPR response for carbon ions is higher than that for nitrogen ions. Water solutions of irradiated sucrose exhibit UV spectrum with absorption maximum at 267 nm, attributed to the recombination products of free radicals. The UV band intensity depends on the absorbed dose radiation. The UV spectra obtained for carbon, nitrogen and gamma rays irradiated sucrose are also compared.

  9. Influence of UV-Irradiation on Latent Tracks in Polyethylene Terephthalate Films

    International Nuclear Information System (INIS)

    Wen Qi; Wang Peng-Fei; Ling Yun; Wang Mao; Yan Dong-Xiao; Wang Yu-Gang; Cao Xing-Zhong; Wang Bao-Yi

    2016-01-01

    Polyethylene terephthalate (PET) films in thickness of 12 μm are irradiated by Xe and Au ions at the energies of 9.5 and 11.4MeV/u and with the ion fluence from 5 × 10"9 cm"−"2 to 1 × 10"1"1 cm"−"2. After irradiation, ultra-violet lights are used to illuminate the samples with latent tracks at the wavelength of 365 nm with flux density of 4.2 mW/cm"−"2. UV-irradiation effects on tracked PET are investigated by the UV-vis spectrum and positron annihilation lifetime spectroscopy (PALS). It is found that carbonaceous clusters in PET films are generated by ion irradiation and decomposed with UV illumination by calculating the optical energy band gap E_g in the UV-vis spectrum. The free volumes behave differently in track and bulk after UV illumination. In our experiment, the PALS results show an increase in radius and density of free volume in tracked PET films after UV treatment, which indicates an expansion in radius of latent tracks. (paper)

  10. Near UV Aerosol Group Report

    Science.gov (United States)

    Torres, Omar

    2013-01-01

    2012-13 Report of research on aerosol and cloud remote sensing using UV observations. The document was presented at the 2013 AEROCENTER Annual Meeting held at the GSFC Visitors Center, May 31, 2013. The Organizers of the meeting are posting the talks to the public Aerocentr website, after the meeting.

  11. Poling of UV-written Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Hübner, Jörg

    1999-01-01

    We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months......We report poling of UV-written silica waveguides. Thermal poling induces an electro-optic coefficient of 0.05 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. No measurable decay in the induced electro-optic effect was detected after nine months...

  12. Radiation damage and repair in cells and cell components. Progress report, November 1, 1977--October 31, 1978. [Uv and x radiation, bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Fluke, D.J.; Pollard, E.C.

    1978-01-01

    Progress is reported on the following research projects: coordinate induction of mutagenesis, radioresistance, and inhibition of post-radiation DNA degradation; radioinduced filamentation; action spectrum for induction of K12 lambda phage; effects of uv radiation on cells in the frozen state; dependence of mutagenesis on wavelength of uv; and w-reactivation of x-irradiated phage lambda. (HLW)

  13. Many channel spectrum unfolding

    International Nuclear Information System (INIS)

    Najzer, M.; Glumac, B.; Pauko, M.

    1980-01-01

    The principle of the ITER unfolding code as used for the many channel spectrum unfolding is described. Its unfolding ability is tested on seven typical neutron spectra. The effect of the initial spectrum approximation upon the solution is discussed

  14. Pulsar Emission Spectrum

    OpenAIRE

    Gruzinov, Andrei

    2013-01-01

    Emission spectrum is calculated for a weak axisymmetric pulsar. Also calculated are the observed spectrum, efficiency, and the observed efficiency. The underlying flow of electrons and positrons turns out to be curiously intricate.

  15. Autism Spectrum Disorder

    Science.gov (United States)

    ... Caregiver Education » Fact Sheets Autism Spectrum Disorder Fact Sheet What is autism spectrum disorder? What are some ... of mutations in individual genes but rather spontaneous coding mutations across many genes. De novo mutations may ...

  16. UV and vacuum-UV biological spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Ito, Amando Siuiti

    1996-01-01

    Full text. Synchrotron radiation has been used as light source in the UV and VUV region for the study of many biological systems. In the time domain, measurements are made that allow the observation of dynamics and kinetics of biomolecules like proteins and peptides, using the fluorescent properties of either intrinsic or extrinsic probes. Optical activity of groups inside biomolecules allows the use of circular dichroism techniques to generate structural information and to follow processes like protein folding. Confocal scanning of synchrotron light generates microscopy resolution below 100 nm, allowing the creation of high quality three dimensional images of biological samples, and the collection of fluorescence originated from microvolumes inside the samples. We propose a station at LNLS for these three techniques: time-resolved fluorescence, circular dischroism and confocal microscopy, using UV and VUV light. (author)

  17. UV Reflectance of Jupiter's Moon Europa and Asteroid (16) Psyche

    Science.gov (United States)

    Becker, T. M.; Retherford, K. D.; Roth, L.; Hendrix, A.; McGrath, M. A.; Cunningham, N.; Feaga, L. M.; Saur, J.; Elkins-Tanton, L. T.; Walhund, J. E.; Molyneux, P.

    2017-12-01

    Surface reflectance observations of solar system objects in the UV are not only complimentary to longer wavelength observations for identifying surface composition, but can also reveal new and meaningful information about the surfaces of those bodies. On Europa, far-UV (FUV) spectral observations made by the Hubble Space Telescope (HST) show that the surface lacks a strong water ice absorption edge near 165 nm, which is intriguing because such a band has been detected on most icy satellites. This may suggest that radiolytic processing by Jupiter's magnetosphere has altered the surface, causing absorption at wavelengths longward of the H2O edge, masking this feature. Additionally, the FUV spectra are blue (increasing albedo with shorter wavelengths), and regions that are observed to be dark in the visible appear bright in the FUV. This spectral inversion, also observed on the Moon and some asteroids, may provide insight into the properties of the surface material and how they are processed.We also explore the UV reflectance spectra of the main belt asteroid (16) Psyche. This asteroid is believed to be the metallic remnant core of a differentiated asteroid, stripped of its mantle through collisions. However, there is speculation that the asteroid could have formed as-is from highly reduced metal-rich material near the Sun early in the formation of the solar system. Further, spectral observations in the infrared have revealed pyroxene and hydroxyl on the asteroid's surface, complicating the interpretation that (16) Psyche is a pure metallic object. Laboratory studies indicate that there are diagnostic spectral features in the UV that could be useful for determining the surface composition. We obtained HST observations of Psyche from 160 - 300 nm. Preliminary results show a featureless, red-sloped spectrum, inconsistent with significant amounts of pyroxene on the surface. We will present the spectra of Europa and the asteroid (16) Psyche and discuss the unique details

  18. Symbiotic star UV emission and theoretical models

    International Nuclear Information System (INIS)

    Kafatos, M.

    1982-01-01

    Observations of symbiotic stars in the far UV have provided important information on the nature of these objects. The canonical spectrum of a symbiotic star, e.g. RW Hya, Z And, AG Peg, is dominated by strong allowed and semiforbidden lines of a variety of at least twice ionized elements. Weaker emission from neutral and singly ionized species is also present. A continuum may or may not be present in the 1200 - 2000 A range but is generally present in the range 2000 - 3200 A range. The suspected hot subdwarf continuum is seen in some cases in the range 1200 - 2000 A (RW Hya, AG Peg, SY Mus). The presence of an accretion disk is difficult to demonstrate and to this date the best candidate for accretion to a main sequence star remains CI Cyg. A number of equations have been derived by the author that can yield the accretion parameters from the observable quantities. Boundary layer temperatures approximately 10 5 K and accretion rates approximately > 10 -5 solar masses/yr are required for accreting main sequence companions. To this date, though, most of the symbiotics may only require the presence of a approximately 10 5 K hot subdwarf. (Auth.)

  19. Photomorphogenic effects of UV-B radiation on plants: consequences for light competition

    International Nuclear Information System (INIS)

    Barnes, P.W.; Ballaré, C.L.; Caldwell, M.M.

    1996-01-01

    A combination of field and labotatory studies were conducted to explore the nature of photomorphogenic effects of ultraviolet-B radiation (UV-B; 280–320 nm) on plant morphology and to evaluate the ecological consequences of these alterations in morphology for interspecific competition. Under laboratory conditions, seedlings of cucumber (Cucumis sativus L.) and tomato (Lycopersicon esculentum Mill.) exhibited appreciable (ca. 50%) and rapid (< 3h) inhibition in hypocotyl elongation in response to UV-B exposure. In cucumber, this inhibition was reversible, occurred without any associated changes in dry matter production and was caused by UV-B incident on the cotyledons and not the stem or growing tip. Inhibition of stem elongation in etiolated tomato seedlings occurred at least 3 h prior to the onset of accumulation of UV-absorbing pigments and monochromatic UV supplied against a background of visible radiation revealed maximum effectiveness in inhibition around 300 nm. Collectively, these findings suggest that a specific, but yet unidentified, UV-B photoreceptor is involved in mediating certain morphological responses to UV-B. For mixtures of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.), a common weedy competitor, supplemental UV-B irradiation in the field differentially altered shoot morphology which resulted in changes in canopy structure, light interception and calculated stand photosynthesis. It is argued that, because of its asymmetrical nature, competition for light can potentially amplify the effects of UV-B on shoot morphology and may, therefore, be an important mechanism by which changes in the solar UV-B spectrum associated with stratospheric ozone reduction could alter the composition and character of terrestrial vegetation

  20. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  1. UV dependent vitamin D syntheses. UV exposure time balancing for optimum production of the vitamins D3 status in the human body. Final report; UV-abhaengige Vitamin D Synthese. Bilanzierung der Expositionszeit durch UV zur Produktion des optimalen Vitamin D{sub 3}-Bedarfes im menschlichen Koerper. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Knuschke, P.; Lehmann, B.; Pueschel, A.; Roensch, H.

    2012-10-15

    simulated solar radiation or by sunbed UV lamps. All studies of the project (240 volunteers) were structured concerning UV skin type II and III, age and sex. In addition, data on the natural skin protection of the volunteers against UV radiation were measured in order to evaluate possible correlations between individual UV sensitivity and the efficiency of vitamin D synthesis. In result: In winter time, before starting the studies, the mean 25OH-vitamin D serum level of 18 ng/ml of the volunteers was in the deficiency range (< 20 ng/ml). UV exposures of 10 % MED applied twice a week vertically to face and hands caused significant increases of the 25OH-vitamin D serum level. The increase rised with higher UV doses and/or larger skin area exposed to UV radiation of the solar summer spectrum. While the increase of the 25OHvitamin D serum level in the UV cabinet was roughly independent from the basic level, under solar exposure conditions there were distinct variations between subjects as well as different outcomes for the whole group, which possibly depended on low outdoor temperatures during the solar exposures. Exposures by sunbed UV lamps lead to decreasing efficiencies in vitamin D production. An increase of the biologically effective UV dose and/or of the UV-exposed skin area decreased the vitamin D efficiency down to 30 % compared to simulated solar radiation. Because of strong differences in UV erythema sensitivity of the skin of different anatomical locations, we hypothesized similar relations in the efficiency of UV-induced vitamin D synthesis. The efficiency of UV-induced vitamin D synthesis varies up to 400 % between the anatomical locations of the body. The investigation of the content of provitamin D (7-Dehydrocholesterol), the source of the vitamin D synthesis in the skin, and of the influence of UV exposure on the level of this content results in new findings, too. Suberythemal UV exposures do not influence the 7-DHC-concentration in the skin. 1 MED leads to a

  2. Investigation of the use of FXG gel dosimeter for UV radiation detection

    International Nuclear Information System (INIS)

    Bero, M.; Abu Kassem, I.

    2009-02-01

    The radio-chromic chemical radiation dosimeter is well known type of detectors that have been used in the measurement application of radiation dose resulting for ionizing radiation such as γ and X-rays. The detector materials consist of mainly water with added gelatin powder that gives the detector its solid shape. Other chemicals sensitive to radiation are also added to form the Ferrous-sulfate Xylenol-orange Gelatin gel detector (FXG). Ionizing radiation effects appears as an increase in the optical absorbance within a defined range of wavelengths located in the visible region of the light spectrum. These visible changes in the materials optical characteristic as a result of radiation exposure is proportional to the radiation absorbed dose at certain wave lengths. Ultraviolet radiation was found to produce similar effects in the FXG detector materials; hence we suggested studying the UV effects in details. It is known that UV radiation carry relatively high quantum energies big enough to enhance important chemical and biological reactions in some exposed medium. This study examines the most important properties required for the FXG detector to be used as a UV monitoring system that is capable of measuring the absorbed UV radiation dose. The study also works on finding chemical detector structure that is easy to be used for simulating the UV interactions with human body. It has been shown that the optical absorbance of standard size FXG samples increases linearly with the exposure time to UV radiation produced by a sun simulator source, when the beam is filtered to produces exposure similar to that found in nature. However, the UV effects are also influenced by the applied UV radiation spectrum used for irradiation as well as the thicknesses of the FXG materials.(authors)

  3. UV Tanning Equipment | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

    Sun lamps and tanning equipment emit ultraviolet (UV) rays. People who are exposed to UV rays over a long period of time are more likely to develop skin cancer. People with light skin are in more danger because their skin is more sensitive to UV rays.

  4. Radical protection by differently composed creams in the UV/VIS and IR spectral ranges.

    Science.gov (United States)

    Meinke, Martina C; Syring, Felicia; Schanzer, Sabine; Haag, Stefan F; Graf, Rüdiger; Loch, Manuela; Gersonde, Ingo; Groth, Norbert; Pflücker, Frank; Lademann, Jürgen

    2013-01-01

    Modern sunscreens are well suited to provide sufficient protection in the UV range because the filter substances absorb or scatter UV radiation. Although up to 50% of radicals are formed in the visible and infrared spectral range during solar radiation protection strategies are not provided in this range. Previous investigations of commercially available products have shown that in addition to physical filters, antioxidants (AO) are necessary to provide protective effects in the infrared range by neutralizing already formed radicals. In this study, the efficacy of filter substances and AO to reduce radical formation in both spectral ranges was investigated after UV/VIS or IR irradiation. Optical properties and radical protection were determined for the investigated creams. It was found that organic UV filters lower radical formation in the UV/VIS range to 35% compared to untreated skin, independent of the presence of AO. Further reduction to 14% was reached by addition of 2% physical filters, whereas physical filters alone were ineffective in the UV/VIS range due to the low concentration. In contrast, this filter type reduced radical formation in the IR range significantly to 65%; similar effects were aroused after application of AO. Sunscreens which contain organic UV filters, physical filters and AO ensure protection in the complete solar spectrum. © 2013 The American Society of Photobiology.

  5. Thermoluminescence dependence on the wavelength of monochromatic UV-radiation in Cu-doped KCl and KBr at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Perez R, A.; Piters, T.; Aceves, R.; Rodriguez M, R.; Perez S, R., E-mail: rperez@cifus.uson.mx [Universidad de Sonora, Departamento de Investigaciones en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

    2014-08-15

    Thermoluminescence (Tl) dependence on the UV irradiation wavelengths from 200 to 500 nm in Cu-doped KCl and KBr crystals with different thermal treatment has been analyzed. Spectrum of the Tl intensity of each material show lower intensity at wavelengths longer than 420 nm. The Tl intensity depends on the irradiation wavelength. Structure of the Tl intensity spectrum of each sample is very similar to the structure of its optical absorption spectrum, indicating that at each wavelength, monochromatic radiation is absorbed to produce electronic transitions and electron hole pairs. Thermoluminescence of materials with thermal treatment at high temperature shows electron-hole trapping with less efficiency. The results show that Cu-doped alkali-halide materials are good detectors of a wide range of UV monochromatic radiations and could be used to measure UV radiation doses. (Author)

  6. Thermoluminescence dependence on the wavelength of monochromatic UV-radiation in Cu-doped KCl and KBr at room temperature

    International Nuclear Information System (INIS)

    Perez R, A.; Piters, T.; Aceves, R.; Rodriguez M, R.; Perez S, R.

    2014-08-01

    Thermoluminescence (Tl) dependence on the UV irradiation wavelengths from 200 to 500 nm in Cu-doped KCl and KBr crystals with different thermal treatment has been analyzed. Spectrum of the Tl intensity of each material show lower intensity at wavelengths longer than 420 nm. The Tl intensity depends on the irradiation wavelength. Structure of the Tl intensity spectrum of each sample is very similar to the structure of its optical absorption spectrum, indicating that at each wavelength, monochromatic radiation is absorbed to produce electronic transitions and electron hole pairs. Thermoluminescence of materials with thermal treatment at high temperature shows electron-hole trapping with less efficiency. The results show that Cu-doped alkali-halide materials are good detectors of a wide range of UV monochromatic radiations and could be used to measure UV radiation doses. (Author)

  7. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection

    OpenAIRE

    Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2017-01-01

    In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on ...

  8. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  9. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

  10. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  11. Investigation of UV photocurable microcapsule inner crosslink extent

    Science.gov (United States)

    Li, Xiaowei; Meng, Shuangshuang; Lai, Weidong; Yu, Haiyang; Fu, Guangsheng

    2008-11-01

    UV photocuring technology has encountered increased applications in recent years, which finds a variety of applications on protective coating of the optical-fiber, ink and optical recording materials. Combined with techniques of photohardenable, microcapsule, heat-sensitive and interface-polymerization method, a novel photoheat sensitive recording material of non-silver salt is explored in this thesis. Microcapsules are particulate substance with a core and shell structure, where photopolymerizable composition, monofunctional/polyfunctional diluents, photopolymerization initiator, photosensitivity enhancing agent and dye precursor are encapsulated as the internal phase. In this paper introduced the characteristics and curing mechanism of photo-sensitive microcapsule materials. The photocuring process may be a complex-function with photopolymerizable compound and photopolymerization initiator. For the sake of high photocuring speed and degree, optimal photo-sensitive materials were selected. In order to match with the light source excitation wavelength and absorb more wider ultraviolet band, combined type of photo-polymerization initiators were employed. With the kinds and dosage of photopolymerization initiator changing, the photocuring speed and quality can be ameliorated. Through studying the UV-visible absorption spectrum and infra-red spectrum of the material , the optical response property of the inner compound can be obtained.

  12. Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

    Science.gov (United States)

    Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

    2011-02-01

    A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Spectral properties of plant leaves pertaining to urban landscape design of broad-spectrum solar ultraviolet radiation reduction

    Science.gov (United States)

    Yoshimura, Haruka; Zhu, Hui; Wu, Yunying; Ma, Ruijun

    2010-03-01

    Human exposure to harmful ultraviolet (UV) radiation has important public health implications. Actual human exposure to solar UV radiation depends on ambient UV irradiance, and the latter is influenced by ground reflection. In urban areas with higher reflectivity, UV exposure occurs routinely. To discover the solar UV radiation regulation mechanism of vegetation, the spectral reflectance and transmittance of plant leaves were measured with a spectrophotometer. Typically, higher plants have low leaf reflectance (around 5%) and essentially zero transmittance throughout the UV region regardless of plant species and seasonal change. Accordingly, incident UV radiation decreases to 5% by being reflected and is reduced to zero by passing through a leaf. Therefore, stratified structures of vegetation are working as another terminator of UV rays, protecting whole terrestrial ecosystems, while vegetation at waterfronts contributes to protect aquatic ecosystems. It is possible to protect the human population from harmful UV radiation by urban landscape design of tree shade and the botanical environment. Even thin but uniformly distributed canopy is effective in attenuating UV radiation. To intercept diffuse radiation, UV screening by vertical structures such as hedges should be considered. Reflectivity of vegetation is around 2%, as foliage surfaces reduce incident UV radiation via reflection, while also eliminating it by transmittance. Accordingly, vegetation reduces incident UV radiation to around 2% by reflection. Vegetation influence on ambient UV radiation is broad-spectrum throughout the UV region. Only trees provide cool UV protective shade. Urban landscapes aimed at abating urban heat islands integrated with a reduction of human UV over-exposure would contribute to mitigation of climate change.

  14. Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in Heliconius butterflies

    OpenAIRE

    Briscoe, Adriana D.; Bybee, Seth M.; Bernard, Gary D.; Yuan, Furong; Sison-Mangus, Marilou P.; Reed, Robert D.; Warren, Andrew D.; Llorente-Bousquets, Jorge; Chiao, Chuan-Chin

    2010-01-01

    The butterfly Heliconius erato can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-cis-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that H. erato has a second UV opsin mRNA (UVRh2)—a previously undescribed duplication of this gene among Lepidoptera. To investigate its evolutionary origin, we scre...

  15. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  16. A novel research model for evaluating sunscreen protection in the UV-A1.

    Science.gov (United States)

    Figueiredo, Sônia Aparecida; de Moraes, Dayane Cristina; Vilela, Fernanda Maria Pinto; de Faria, Amanda Natalina; Dos Santos, Marcelo Henrique; Fonseca, Maria José Vieira

    2018-01-01

    The use of a broad spectrum sunscreen is considered one of the main and most popular measures for preventing the damaging effects of ultraviolet radiation (UVR) on the skin. In this study we have developed a novel in vitro method to assess sunscreens efficacy to protect calcineurin enzyme activity, a skin cell marker. The photoprotective efficacy of sunscreen products was assessed by measuring the UV-A1 radiation-induced depletion of calcineurin (Cn) enzyme activity in primary neonatal human dermal fibroblast (HDFn) cell lysates. After exposure to 24J/cm 2 UV-A1 radiation, the sunscreens containing larger amounts of UV-A1 filters (brand B), the astaxanthin (UV-A1 absorber) and the Tinosorb® M (UV-A1 absorber) were capable of preventing loss of Cn activity when compared to the sunscreens formulations of brand A (low concentration of UV-A1 filters), with the Garcinia brasiliensis extract (UV-B absorber) and with the unprotected cell lysate and exposed to irradiation (Irradiated Control - IC). The Cn activity assay is a reproducible, accurate and selective technique for evaluating the effectiveness of sunscreens against the effects of UV-A1 radiation. The developed method showed that calcineurin activity have the potential to act as a biological indicator of UV-A1 radiation-induced damages in skin and the assay might be used to assess the efficacy of sunscreens agents and plant extracts prior to in vivo tests. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. UV reflection properties of plumage and skin of domesticated turkeys (Meleagris gallopavo f. dom.) as revealed by UV photography.

    Science.gov (United States)

    Bartels, T; Lütgeharm, J-H; Wähner, M; Berk, J

    2017-12-01

    Reflection and fluorescence properties of feathered and non-feathered body regions of white- and bronze-colored fattening turkeys of various ages were examined by ultraviolet (UV) photography. The examinations were carried out on 20 white-feathered fattening turkeys (B.U.T. 6; 10 males, 10 females) and 20 bronze-feathered fattening turkeys (Grelier 708; 10 males, 10 females) over a period of 21 weeks. The turkeys were photographed once a wk under long-wave UV (UVA) radiation illumination (λ = 344-407 nm) using a digital camera. A bandpass filter was used for UV reflectography to filter out the visible components of the used light source. A longpass filter was used for UV fluorescence photography to avoid blurring in the image due to chromatic aberration as a result of UV illumination. We found that natal down feathers of white-feathered turkeys showed an intense yellowish-green fluorescence under UVA light. UVA fluorescence also was shown by the natal downs of the slightly melanized plumage areas of bronze turkeys. Vaned feathers of white fattening turkeys reflected UVA radiation. Freshly molted feathers were optically distinguishable from the previous feather generation due to their more intense UVA reflection. In bronze turkeys, both the bright end seams of the dark pennaceous feathers and rectrices and the bright banding of primary and secondary remiges reflected UVA radiation. Intense UVA fluorescence was recognizable in day-old chicks of both color variants on the scutellate scales of the legs and toes. In male turkeys of both color variants, UVA-reflecting parts were recognizable with increasing age on the featherless head region. The UVA-fluorescent and UVA-reflective characteristics of the plumage of fattening turkeys were closely related to the plumage color, the feather type, the molting state, and the age of the birds. Further research is needed regarding the UVA-reflecting properties of the turkey plumage and the effects of full-spectrum illumination

  18. The genetic origins of biosynthesis and light-responsive control of the chemical UV screen of land plants

    International Nuclear Information System (INIS)

    Jorgensen, R.

    1994-01-01

    Most land plants possess the capacity to protect themselves from UV light, and do so by producing pigments that absorb efficiently in the UV-A and UV-B regions of the spectrum while allowing transmission of nearly all photosynthetically useful wavelengths. These UV-absorbing pigments are mainly phenylpropanoids and flavonoids. This chapter summarizes current understanding of the mechanism of UV protection in higher land plants, evaluates the information available from lower land plants and their green-algal relatives, and then considers the possible evolutionary origins of this use of chemical filters for selectively screening UV light from solar radiation. It is proposed that photo control over the biosynthesis of UV-absorbing phenylpropanoids and flavonoids may have evolved in concert with the evolution of the high biosynthetic activity necessary for UV protection. The toxicity of phenylpropanoids and flavonoids has been postulated to have been a barrier to the evolution of an effective chemical UV screen, and that some means for sequestering these compounds and/or for controlling their synthesis probably evolved prior to, or in concert with, the evolution of high rates of biosynthesis. The original photoreceptor and signal transduction system is speculated to have been based on photo isomerization of a phenylpropanoid ester and a pre-existing product feedback mechanism for controlling phenylpropanoid biosynthesis. Understanding the original mechanism for photo control of the chemical UV screen of land plants could be valuable for understanding the adaptability of extant land plants to rising levels of solar UV-B radiation and may suggest genetic strategies for engineering improved UV tolerance in crop plants. (author)

  19. COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

    Directory of Open Access Journals (Sweden)

    О. Міхєєв

    2011-04-01

    Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

  20. Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

    Science.gov (United States)

    Bruner, M.; Brown, W. A.; Haisch, B. M.

    1987-01-01

    A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft X-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the X-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical X-ray observations using this new technique.

  1. The photodiode of UV-range on the basis of ZnSe

    Directory of Open Access Journals (Sweden)

    Perevertailo V. L.

    2010-03-01

    Full Text Available The construction and technology of Shottky photodiode on the basis of ZnSe, sensible in the ultraviolet region of spectrum are considered. Researches of electrophysical and photo-electric descriptions of photodiodes of Shottky Nі–ZnSe(Te,O–Іn are conducted and it is shown, that they can be applied in devices for radiometry and dissymmetry UV radiations in the ranges UVA, UVB and UVC. Comparison of parameters of developed UV photodiodes based on ZnSe with analogues showed that small capacitance and low value of dark current is their substantial difference of other ones.

  2. Detection of Explosives on Surfaces Using UV Raman Spectroscopy: Effect of Substrate Color

    Science.gov (United States)

    2017-10-01

    257.23-nm excitation (25 mW at the laser) using 2.5-s integration time and 100 accumulations. Each spectrum is offset by 400 counts from the one...tens of meters have been reported. The testing of UV Raman spectroscopy systems for standoff UV Raman spectroscopy has been generally limited to bare...SP2500A 500-mm focal length monochromator and a PIXIS 400 × 3048 pixel charge-coupled device (CCD) camera (Princeton Instruments, Trenton, NJ). An

  3. Action spectrum for inhibition by ultraviolet radiation of photosystem 2 activity in spinach thylakoids

    International Nuclear Information System (INIS)

    Bornman, J.F.; Bjoern, L.O.; Aakerlund, H.-E.

    1984-01-01

    The effect of ultraviolet (UV) radiation (half-band width 10 nm) in the wavelength range 248-340 nm on chlorophyll fluorescence from a thin layer of spinach thylakoid suspension was investigated. It was found that the parameter most sensitive to UV radiation was the rise time of variable fluorescence. The increase in rise time was proportional to UV photon fluence and was used for the determination of an action spectrum. The action spectrum falls off from a maximum at ca. 275 nm towards longer wavelengths and rises from a minimum at 260 nm towards shorter wavelengths. The results also suggest that the UV inhibition is mainly on the PS 2 oxidizing side. Possibly damage is also inflicted to the PS 2 reaction center. (orig.)

  4. 5G Spectrum Sharing

    OpenAIRE

    Nekovee, Maziar; Rudd, Richard

    2017-01-01

    In this paper an overview is given of the current status of 5G industry standards, spectrum allocation and use cases, followed by initial investigations of new opportunities for spectrum sharing in 5G using cognitive radio techniques, considering both licensed and unlicensed scenarios. A particular attention is given to sharing millimeter-wave frequencies, which are of prominent importance for 5G.

  5. Autism Spectrum Disorder (ASD)

    Science.gov (United States)

    ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Autism spectrum disorder (ASD) is a developmental disability that can cause ... work. Autism: What's New MMWR article: Prevalence of Autism Spectrum Disorder Data Community Report Press release: Autism Prevalence Slightly ...

  6. UV lamp for photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Cardoso, M.J.B.; Landers, R.; Sundaram, V.S.

    1983-01-01

    An UV lamp and a differential pumping system which enables to couple the lamp to an ultra-high vacuum chamber (10 -9 torr) without using windows, are described. The differential between the pressure inside the discharge chamber and the one in de UHV region, which is of 10 8 -10 9 , is achieved with two pumping states separated by pyrex capillaries having an internal diameter of 0.6 mm. In the first stage, a mechanical pump (10 -3 torr) is used; in the second stage, a diffusor pump with a cryogenic trap (N 2 liq - 10 -7 torr) is employed. The lamp produces, when used with high purity He, narrow lines almost clear at 21.2 eV and 40.8 eV, depending on the discharge chamber pressure, thus eliminating the need of a monochromator. As a high voltage source (3 KV), a commercial unit with a good current control was used, ensuring UV beam stability - an essential characteristic for this lamp if it is employed for photoelectron excitation of crystalline samples. (C.L.B.) [pt

  7. Raman spectroscopic analysis of the responds of desert cyanobacterium Nostoc sp under UV-B radiation

    Science.gov (United States)

    Wang, Gaohong; Hao, Zongjie; Hu, Chunxiang; Liu, Yongding

    Cyanobacteria are renowned for tolerating extremes of desiccation, UV radiation, freezethaw cycles, hypersalinity and oligotrophy, which make them as candidate par excellence for terraforming in extraterrestrial planet. Recently Raman spectrum was applied to study the biochemical information changes in different field of life science. In this study, we investigated the respond of desert cyanobactreium Nostoc sp under UV-B radiation via FT-Raman spectra. It was found that the spectral biomarkers of protectant molecular of UV radiation such as β-carotene and scytonemin were induced by UV-B radiation, but Chlorophyll a content was decreased, and also the photosynthesis activity was inhibited significantly. After light adaptation without UV-B radiation, the Chlorophyll a content and photosynthesis activity returned to high level, butβ-carotene and scytonemin content remained in the cells. Those results indicated that desert Cyanobacteria have good adaptation ability for UV-B radiation and synthesis of protectant molecular may be an effective strategy for its adaptation in evolution.

  8. UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B; Niyogi, Krishna K; Ulm, Roman; Goldschmidt-Clermont, Michel

    2016-12-20

    Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast.

  9. UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii

    Science.gov (United States)

    Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B.; Niyogi, Krishna K.; Goldschmidt-Clermont, Michel

    2016-01-01

    Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast. PMID:27930292

  10. Efficient room temperature hydrogen sensor based on UV-activated ZnO nano-network

    Science.gov (United States)

    Kumar, Mohit; Kumar, Rahul; Rajamani, Saravanan; Ranwa, Sapana; Fanetti, Mattia; Valant, Matjaz; Kumar, Mahesh

    2017-09-01

    Room temperature hydrogen sensors were fabricated from Au embedded ZnO nano-networks using a 30 mW GaN ultraviolet LED. The Au-decorated ZnO nano-networks were deposited on a SiO2/Si substrate by a chemical vapour deposition process. X-ray diffraction (XRD) spectrum analysis revealed a hexagonal wurtzite structure of ZnO and presence of Au. The ZnO nanoparticles were interconnected, forming nano-network structures. Au nanoparticles were uniformly distributed on ZnO surfaces, as confirmed by FESEM imaging. Interdigitated electrodes (IDEs) were fabricated on the ZnO nano-networks using optical lithography. Sensor performances were measured with and without UV illumination, at room temperate, with concentrations of hydrogen varying from 5 ppm to 1%. The sensor response was found to be ˜21.5% under UV illumination and 0% without UV at room temperature for low hydrogen concentration of 5 ppm. The UV-photoactivated mode enhanced the adsorption of photo-induced O- and O2- ions, and the d-band electron transition from the Au nanoparticles to ZnO—which increased the chemisorbed reaction between hydrogen and oxygen. The sensor response was also measured at 150 °C (without UV illumination) and found to be ˜18% at 5 ppm. Energy efficient low cost hydrogen sensors can be designed and fabricated with the combination of GaN UV LEDs and ZnO nanostructures.

  11. Efficiency of ocular UV protection by clear lenses.

    Science.gov (United States)

    Rifai, Katharina; Hornauer, Matthias; Buechinger, Ramona; Schoen, Roland; Barraza-Bernal, Maria; Habtegiorgis, Selam; Glasenapp, Carsten; Wahl, Siegfried; Mappes, Timo

    2018-04-01

    Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario.

  12. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

    There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

  13. [Light protection: principles of UV protection].

    Science.gov (United States)

    Stege, H; Mang, R

    2006-05-01

    UV radiation is responsible for the induction of epithelial and melanocytic skin cancer, photoaging, and photodermatoses. UV protection is necessary to prevent damage caused by non-physiologic exposure. UV protection includes not only reduction of sun exposure but also use of sun protective filters, UV protective clothes, DNA repair enzymes, and antioxidant supplementation. Consumers are uncertain about the possibilities and limitations of commercial sun protection measures. Dermatologists must explain protective measures to the general public which continues to believe that UV-tanned skin is healthy. The sunscreen market is a highly competitive but lucrative market. The range of products with different designations and promises makes difficult for both consumers and dermatologists to determine what is sensible UV protection.

  14. Oscillations in the spectrum of nonlinear Thomson-backscattered radiation

    Directory of Open Access Journals (Sweden)

    C. A. Brau

    2004-02-01

    Full Text Available When an electron beam collides with a high-intensity laser beam, the spectrum of the nonlinear Thomson scattering in the backward direction shows strong oscillations like those in the spectrum of an optical klystron. Laser gain on the backward Thomson scattering is estimated using the Madey theorem, and the results suggest that Thomson-backscatter free-electron lasers are possible at wavelengths extending to the far uv using a terawatt laser beam from a chirped-pulse amplifier and a high-brightness electron beam from a needle cathode.

  15. UV-Induced Cell Death in Plants

    Science.gov (United States)

    Nawkar, Ganesh M.; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-01

    Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280–320 nm) and UV-A (320–390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD). PMID:23344059

  16. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  17. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  18. The research on a novel type of the solar-blind UV head-mounted displays

    Science.gov (United States)

    Zhao, Shun-long

    2011-08-01

    Ultraviolet technology of detecting is playing a more and more important role in the field of civil application, especially in the corona discharge detection, in modern society. Now the UV imaging detector is one of the most important equipments in power equipment flaws detection. And the modern head-mounted displays (HMDs) have shown the applications in the fields of military, industry production, medical treatment, entertainment, 3D visualization, education and training. We applied the system of head-mounted displays to the UV image detection, and a novel type of head-mounted displays is presented: the solar-blind UV head-mounted displays. And the structure is given. By the solar-blind UV head-mounted displays, a real-time, isometric and visible image of the corona discharge is correctly displayed upon the background scene where it exists. The user will see the visible image of the corona discharge on the real scene rather than on a small screen. Then the user can easily find out the power equipment flaws and repair them. Compared with the traditional UV imaging detector, the introducing of the HMDs simplifies the structure of the whole system. The original visible spectrum optical system is replaced by the eye in the solar-blind UV head-mounted displays. And the optical image fusion technology would be used rather than the digital image fusion system which is necessary in traditional UV imaging detector. That means the visible spectrum optical system and digital image fusion system are not necessary. This makes the whole system cheaper than the traditional UV imaging detector. Another advantage of the solar-blind UV head-mounted displays is that the two hands of user will be free. So while observing the corona discharge the user can do some things about it. Therefore the solar-blind UV head-mounted displays can make the corona discharge expose itself to the user in a better way, and it will play an important role in corona detection in the future.

  19. The UV Survey Mission Concept, CETUS

    Science.gov (United States)

    Heap, Sara; and the CETUS Team

    2018-01-01

    In March 2017, NASA selected CETUS for study of a Probe-class mission concept. W. Danchi is the CETUS PI, and S. Heap is the Science PI. CETUS is primarily a UV survey telescope to complement survey telescopes of the 2020’s including E-ROSITA, Subaru Hyper Suprime Cam and Prime-Focus Spectrograph, WFIRST, and the Square Kilometer Array. CETUS comprises a 1.5-m wide-field telescope and three science instruments: a wide-field (1045” on a side) far-UV and near-UV camera; a similarly wide-field near-UV multi-object spectrograph utilizing a next-generation micro-shutter array; and a single-object spectrograph with options of spectral region (far-UV or near-UV) and spectral resolving power (2,000 or 40,000). The survey instruments will operate simultaneously thereby producing wide-field images in the near-UV and far-UV and a spectrogram containing near-UV spectra of up to 100 sources free of spectral overlap and astronomical background. ln concert with other survey telescopes, CETUS will focus on understanding galaxy evolution at cosmic noon (z~1-2).

  20. Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in Heliconius butterflies

    Science.gov (United States)

    Briscoe, Adriana D.; Bybee, Seth M.; Bernard, Gary D.; Yuan, Furong; Sison-Mangus, Marilou P.; Reed, Robert D.; Warren, Andrew D.; Llorente-Bousquets, Jorge; Chiao, Chuan-Chin

    2010-01-01

    The butterfly Heliconius erato can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-cis-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that H. erato has a second UV opsin mRNA (UVRh2)—a previously undescribed duplication of this gene among Lepidoptera. To investigate its evolutionary origin, we screened eye cDNAs from 14 butterfly species in the subfamily Heliconiinae and found both copies only among Heliconius. Phylogeny-based tests of selection indicate positive selection of UVRh2 following duplication, and some of the positively selected sites correspond to vertebrate visual pigment spectral tuning residues. Epi-microspectrophotometry reveals two UV-absorbing rhodopsins in the H. erato eye with λmax = 355 nm and 398 nm. Along with the additional UV opsin, Heliconius have also evolved 3-hydroxy-DL-kynurenine (3-OHK)-based yellow wing pigments not found in close relatives. Visual models of how butterflies perceive wing color variation indicate this has resulted in an expansion of the number of distinguishable yellow colors on Heliconius wings. Functional diversification of the UV-sensitive visual pigments may help explain why the yellow wing pigments of Heliconius are so colorful in the UV range compared to the yellow pigments of close relatives lacking the UV opsin duplicate. PMID:20133601

  1. New technologies for UV detectors

    Science.gov (United States)

    Joseph, C. L.

    1993-01-01

    Several technologies are currently being developed, leading to substantial improvements in the performance of UV detectors or significant reductions in power or weight. Four technologies discussed are (1) thin-film coatings to enhance the UV sensitivity of CCD's, (2) highly innovative magnet assemblies that dramatically reduce weight and result in virtually no external flux, (3) new techniques for curving microchannel plates (MCP's) so that single plates can be used to prevent ion feedback and present highly localized charge clouds to an anode structure, and (4) high-performance alternatives to glass-based MCP's. In item (2), for example, very robust magnets are made out of rare earth materials such as samarium cobalt, and cladding magnets are employed to prevent flux from escaping from the detector into the external environment. These new ultralight magnet assemblies are able to create strong, exceptionally uniform magnetic fields for image intensification and focusing of photoelectrons. The principle advantage of such detectors is the quantum efficiencies of 70-80 percent obtained throughout ultraviolet wavelengths (900-2000 A), the highest of any device. Despite the improvements achieved under item (3), high-performance alternatives to conventional glass-based MCP's potentially offer three distinct new advantages that include (1) a 30-100-fold improvement in dynamic range resulting in correspondingly higher signal-to-noise ratios, (2) the use of pure dielectric and semiconductor materials that will not outgas contaminants that eventually destroy photocathodes, and (3) channels that have constant spacing providing long-ranged order since the plates are made using photolithography techniques from the semiconductor industry. The manufacturers of these advanced-technology MCP's, however, are a couple of years away from actually producing a functioning image intensifier. In contrast to the use of CCD's for optical, ground based observations, there is no single

  2. UV-extending Ghost Inflation

    CERN Document Server

    Ivanov, Mikhail M

    2014-01-01

    We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether theory or its khronometric version. Compared to previous works on ghost inflation our setup allows to go beyond the study of small perturbations and include the background dynamics in a unified framework. In the specific regime when the expansion of the Universe is dominated by the kinetic energy of the inflaton we find that the model predicts rather high tensor-to-scalar ratio r ~ 0.02 $\\div$ 0.2 and non-Gaussianity of equilateral type with f_NL in the range from -50 to -5.

  3. Single-strand breaks induced in Bacillus subtilis DNA by ultraviolet light: action spectrum and properties

    International Nuclear Information System (INIS)

    Peak, M.J.; Peak, J.G.

    1982-01-01

    The induction of single-strand breaks (alkali-labile bonds plus frank breaks) in the DNA of Bacillus subtilis irradiated in vivo by monochromatic UV light at wavelengths from 254 to 434nm was measured. The spectrum consists of a major far-UV (below 320nm) component and a minor near-UV shoulder. A mutant deficient in DNA polymerase I accumulates breaks caused by near-UV (above 320nm) wavelengths faster than the wild-type strain proficient in polymerase I. Measurable breaks in extracted DNA are induced at a higher frequency than those induced in vivo. Anoxia, glycerol, and diazobicyclo (2.2.2.) octane inhibit break formation in extracted DNA. Alkali-labile bonds induced by 365-nm UV radiation are largely (78%) covalent bond chain breaks, the remainder consists of true alkali-labile bonds, probably apurinic and apyrimidinic sites. (author)

  4. Quasi-simultaneous observations of BL Lac object Mrk 501 in X-ray, UV, visible, IR, and radio frequencies

    Science.gov (United States)

    Kondo, Y.; Worrall, D. M.; Oke, J. B.; Yee, H. K. C.; Neugebauer, G.; Matthews, K.; Feldman, P. A.; Mushotzky, R. F.; Hackney, R. L.; Hackney, K. R. H.

    1981-01-01

    Observations in the X-ray, UV, visible, IR and radio regions of the BL Lac object Mrk 501 made over the course of two months are reported. The measurements were made with the A2 experiment on HEAO 1 (X-ray), the SWP and LWR cameras on IUE (UV), the 5-m Hale telescope (visible), the 2.5-m telescope at Mount Wilson (IR), the NRAO 92-m radio telescope at Green Bank (4750 MHz) and the 46-m radio telescope at the Algonquin Observatory (10275 and 10650 MHz). The quasi-simultaneously observed spectral slope is found to be positive and continuous from the X-ray to the UV, but to gradually flatten and possibly turn down from the mid-UV to the visible; the optical-radio emission cannot be accounted for by a single power law. The total spectrum is shown to be compatible with a synchrotron self-Compton emission mechanism, while the spectrum from the visible to the X-ray is consistent with synchrotron radiation or inverse-Compton scattering by a hot thermal electron cloud. The continuity of the spectrum from the UV to the X-ray is noted to imply a total luminosity greater than previous estimates by a factor of 3-4.

  5. Expression of UV-irradiated adenovirus in normal and UV-sensitive Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1985-01-01

    The chinese hamster ovary (CHO) cell mutants UV-20, UV-24, and UV-41 are abnormally sensitive to UV and harbour various defects lin their ability to repair cellular DNA. This study has examined the expression of UV-irradiated AD2 in these cells. HCR of UV-irradiated Ad2, as measured by viral structural antigen (Vag) formation or progeny production, was found to be similar for the normal and the UV-sensitive CHO strains. UV-irradiation of Ad2 (1200 J/m/sup 2/) resulted in a delay of Vag expression of 18 hours in normal human fibroblasts, which is thought to reflect the time required for removal of UV-induced lesions from the DNA before viral DNA synthesis can proceed. However, a similar UV-irradiation of Ad2 did not result in a delay of Vag expression for infection of CHO cells, suggesting that UV-induced lesions in Ad2 DNA do not inhibit its replication in CHO cells. These results indicate a fundamental difference in the processing of UV-irradiated AD2-DNA in CHO as compared to human cells

  6. A Study of UV Spectral Transmission Through Different Transparent Media with Spectrophotometer

    Directory of Open Access Journals (Sweden)

    R B Gadgil

    1981-01-01

    Full Text Available This experiment was carried out with the help of spectrophotometer using an artificial UV light source to find -out the percentage transmission of UVA and UVB regions of the UV spectrum. The aim of the experiment was to select the transparent medium which would block mum UVB at the same time allowing mammum UVA to pass through thus reducing the unwanted side effects of UVB light and reducing the efficacy of PUVASOL. It was observed that an ordinary plain 3.3 mm colorless glass was the best transparent medium and with its use a simple solarium could be constructed to treat patients on PUVASOL with sunlight as the source of UV light.

  7. The competitive action of UV of different wavelengths of the survival of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ivanova, Eh.V.; Pospelov, M.E.; Strakhovskaya, M.G.; Frajkin, G.Ya.

    1982-01-01

    During investigation into combined action of different wavelengths of UV spectrum on Saccharomyces cerevisiae yeast (strains XII and CI-9) it was established that 334 nm preliminary irradiation causes photoprotection of cells from lethal action of 254 and 313 nm UV-rays. During 334 postradiation irradiation strengthening of lethal action of 254 and 313 nm UV-rays for strain XII, not capable of photoreactivation, is observed. Using specific inhibitor of serotonin-biosynthesis- parachlorophenyl alanine it is shown that 334 nm serotonin synthesis induced by light lies in the base of mechanism of both effects. The effect of postradiation action of 334 nm light for strain CI-9, capable of photoreactivation, depends on interaction of two different photobiological reactions caused by light, photoreactivation and photoinduced synthesis of serotonin

  8. Absorption of uv-radiation by Chibro trademark -Uvelin eye drops

    International Nuclear Information System (INIS)

    Schreder, J.G.; Blumthaler, M.; Daxer, A.; Ettl, A.

    1998-01-01

    The preparation Chibro trademark -Uvelin is recommended against both solar and artificial uv-radiation. At wavelengths greater than 290 nm and at an effective layer thickness of 10 μm measurements with a high resolution doublemonochromator showed a transmission larger than 90%. The solar spectrum is characterised by almost no irradiance on the earth's surface for wavelengths smaller than 290 nm due to absorption in the atmospheric ozon layer. Therefore, no significant protective effect of the eye-drops against keratitis and cataract under solar exposure can be expected. A significantly better sagging of the radiation of artificial UV-sources with a high amount of UV-C is reached. The recommended application as chemical protective goggles in this spectral range is not permissible. (orig.) [de

  9. Degradation Studies of Polyolefins Incorporating Transparent Nanoparticulate Zinc Oxide UV Stabilizers

    International Nuclear Information System (INIS)

    Ammala, A.; Hill, A.J.; Meakin, P.; Pas, S.J.; Turney, T.W.

    2002-01-01

    Coated and dispersed nanoparticulate zinc oxide is shown to improve ultra violet (UV) stability of polypropylene and high-density polyethylene without changing its characteristic absorption spectrum in the visible region (400-800-nm). The performance of these nanoparticulate UV stabilizers is compared to conventional hindered amine light stabilizers (HALS). QUV accelerated weathering is used to simulate long-term exposure. Positron annihilation lifetime spectroscopy (PALS) is used to provide an indication of physical and chemical changes due to accelerated weathering and is shown to have potential for detecting changes well before other techniques. Visual observation, optical microscopy, carbonyl index, yellowness index and PALS indicate that nanoparticulate zinc oxide gives superior resistance to UV degradation compared to organic HALS at appropriate loading levels

  10. Room-temperature effects of UV radiation in KBr:Eu{sup 2+} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Salas, R; Melendrez, R [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada - IFUNAM, Ensenada, Apartado Postal 2732 Ensenada, BC, 22800 (Mexico); Aceves, R; Rodriguez, R; Barboza-Flores, M [Centro de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088 Hermosillo, Sonora, 83190 (Mexico)

    1996-07-01

    Thermoluminescence and optical absorption measurements have been carried out in KBr:Eu{sup 2+} crystals irradiated with monochromatic UV light (200-300 nm) and x-rays at room temperature. For UV- and x-irradiated crystals strong similarities between the thermoluminescence glow curves have been found, suggesting that the low-energy UV radiation produces the same defects as produced by x-irradiation in this material. The thermoluminescence glow curves are composed of six glow peaks located at 337, 383, 403, 435, 475 and 509 K. Thermal annealing experiments in previously irradiated crystals show clearly a correlation between the glow peak located at 383 K and the F-centre thermal bleaching process. Also, the excitation spectrum for each thermoluminescence glow peak has been investigated, showing that the low-energy radiation induces the formation of F centres. (author)

  11. A vacuum-UV laser-induced fluorescence experiment for measurement of rotationally and vibrationally excited H2

    NARCIS (Netherlands)

    Vankan, P.J.W.; Heil, S.B.S.; Mazouffre, S.; Engeln, R.A.H.; Schram, D.C.; Döbele, H.F.

    2004-01-01

    An experimental setup is built to detect spatially resolved rovibrationally excited hydrogen molecules via laser-induced fluorescence. To excite the hydrogen molecules, laser radiation is produced in the vacuum UV part of the spectrum. The laser radiation is tunable between 120 nm and 230 nm and has

  12. The marine diversity spectrum

    DEFF Research Database (Denmark)

    Reuman, Daniel C.; Gislason, Henrik; Barnes, Carolyn

    2014-01-01

    of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts...... the form of the diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum...... is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0 center dot 5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0 center...

  13. Autism Spectrum Disorder

    Centers for Disease Control (CDC) Podcasts

    This podcast discusses autism spectrum disorder (ASD), a developmental disability that causes problems with social, communication, and behavioral skills. CDC estimates that one in 68 children has been identified as having ASD.

  14. Fetal Alcohol Spectrum Disorders

    Science.gov (United States)

    Alcohol can harm your baby at any stage during a pregnancy. That includes the earliest stages, before ... can cause a group of conditions called fetal alcohol spectrum disorders (FASDs). Children who are born with ...

  15. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  16. Gluonium spectrum in QCD

    International Nuclear Information System (INIS)

    Dominguez, C.A.

    1987-02-01

    The scalar (0 ++ ) and the tensor (2 ++ ) gluonium spectrum is analyzed in the framework of QCD sum rules. Stable eigenvalue solutions, consistent with duality and low energy theorems, are obtained for the mass and width of these glueballs. (orig.)

  17. Spectrum and network measurements

    CERN Document Server

    Witte, Robert A

    2014-01-01

    This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

  18. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K; Leszczynski, K; Visuri, R; Ylianttila, L [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1996-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  19. UV dichroic coatings on metallic reflectors

    International Nuclear Information System (INIS)

    Raghunath, C; Babu, N J; Chandran, K M

    2008-01-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail

  20. UV dichroic coatings on metallic reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Raghunath, C; Babu, N J; Chandran, K M [Hind High Vacuum Co. Pvt. Ltd. No.17, Phase 1, Peenya Industrial Area, Bangalore 560058 (India)

    2008-05-01

    The work presented here explains the design and deposition process of dichroic coating on metallic reflectors developed for UV curing systems. Special designs are adopted to achieve the spectral band and optimized to suit to the requirements. A mirror, which reflects the UV radiation (220 - 400 nm) and absorbs visible and infrared radiation (400 - 2000nm), is described in detail.

  1. UV Bandpass Optical Filter for Microspectometers

    NARCIS (Netherlands)

    Correia, J.H.; Emadi, A.R.; Wolffenbuttel, R.F.

    2006-01-01

    This paper describes the design and modeling of a UV bandpass optical filter for microspectrometers. The materials used for fabricating the multilayer UV filter are: silicon dioxide (SiO2), titanium dioxide (TiO2) and yttrium oxide (Y2O3). The optical filter shows a bandpass response wavelength in

  2. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  3. Discontinuities during UV writing of waveguides

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Andersen, Marc

    2005-01-01

    UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour.......UV writing of waveguides can be hampered by discontinuities where the index change process suddenly shuts down. We show that thermal effects may account for this behaviour....

  4. Direct UV-writing of waveguides

    DEFF Research Database (Denmark)

    Færch, Kjartan Ullitz

    2003-01-01

    induced refractive index change of more than 10-2 have been obtained. New insight, with respect to understanding the UV induced index change obtained by direct UV writing, has been provided, through experiments conducted with such high-pressure loaded germanosilica samples. This include measurements...

  5. Effect of UV laser irradiation on tissue

    International Nuclear Information System (INIS)

    Nakayama, Takeyoshi; Kubo, Uichi

    1992-01-01

    Laser-tissue interactions have been investigated through Electron Probe Micro Analysis (EPMA), UV-visible optical absorption and Fourier Transform Infrared Spectroscopy (FTIR). Three excimer lasers, ArF, KrF and XeCl, were used to irradiate tissue; cow thighbone and gelatin thin film. Features of UV laser irradiation are described. (author)

  6. Exposure to solar UV in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Jokela, K.; Leszczynski, K.; Visuri, R.; Ylianttila, L. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1995-12-31

    Exceptionally low total ozone, up to 40 % below the normal level, was measured over Northern Europe during winter and spring in 1992 and 1993. In 1993 the depletion persisted up to the end of May, resulting in a significant increase in biologically effective ultraviolet (UV) radiation. The increases were significantly smaller in 1992 and 1994 than in 1993. A special interest in Northern Europe is the effect of high reflection of UV from the snow. The period from the mid March to the mid May is critical in Northern Finland, because in that time the UV radiation is intense enough to cause significant biological effects, and the UV enhancing snow still covers the ground. Moreover, there is some evidence of increasing springtime depletions of ozone over Arctic regions. In this study the increase of UV exposure associated with the ozone depletions was examined with measurements and theoretical calculations. The measurements were carried out with spectroradiometrically calibrated Solar Light Model 500 and 501 UV radiometers which measure the erythemally effective UV doses and dose rates. The theoretical UV doses and dose rates were computed with the clear sky model of Green

  7. UV Reconstruction Algorithm And Diurnal Cycle Variability

    Science.gov (United States)

    Curylo, Aleksander; Litynska, Zenobia; Krzyscin, Janusz; Bogdanska, Barbara

    2009-03-01

    UV reconstruction is a method of estimation of surface UV with the use of available actinometrical and aerological measurements. UV reconstruction is necessary for the study of long-term UV change. A typical series of UV measurements is not longer than 15 years, which is too short for trend estimation. The essential problem in the reconstruction algorithm is the good parameterization of clouds. In our previous algorithm we used an empirical relation between Cloud Modification Factor (CMF) in global radiation and CMF in UV. The CMF is defined as the ratio between measured and modelled irradiances. Clear sky irradiance was calculated with a solar radiative transfer model. In the proposed algorithm, the time variability of global radiation during the diurnal cycle is used as an additional source of information. For elaborating an improved reconstruction algorithm relevant data from Legionowo [52.4 N, 21.0 E, 96 m a.s.l], Poland were collected with the following instruments: NILU-UV multi channel radiometer, Kipp&Zonen pyranometer, radiosonde profiles of ozone, humidity and temperature. The proposed algorithm has been used for reconstruction of UV at four Polish sites: Mikolajki, Kolobrzeg, Warszawa-Bielany and Zakopane since the early 1960s. Krzyscin's reconstruction of total ozone has been used in the calculations.

  8. Autism spectrum disorder - Asperger syndrome

    Science.gov (United States)

    ... part of the larger developmental disorder category of autism spectrum disorder . ... American Psychiatric Association. Autism spectrum disorder. ... VA: American Psychiatric Publishing: 2013;50-59. Raviola GJ, ...

  9. UV Radiation Detection Using Optical Sensor Based on Eu3+ Doped PMMA

    Directory of Open Access Journals (Sweden)

    Miluski Piotr

    2016-12-01

    Full Text Available Progress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl methacrylate (PMMA matrix doped by europium was used for testing the optical sensor (optrode construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.

  10. UV-straling in de kas: mogelijkheden en grenzen

    NARCIS (Netherlands)

    Hoffmann, S.

    2000-01-01

    Effect van UV-straling op kleuring van Coleus Blumei 'Wizzard Velvit Red'. Gegevens in bijgaande tabellen: 1) Indeling optische straling; 2) Transmisse voor UV-straling van verschillende dekmaterialen (folie UV, glas UV, glas normaal, folie normaal, folie UV-blok

  11. Vacuum ultraviolet photoabsorption spectroscopy of CH2Cl2 and CD2Cl2 in the energy region 50,000-95,000 cm-1

    Science.gov (United States)

    Mandal, Anuvab; Singh, Param Jeet; Shastri, Aparna; Jagatap, B. N.

    2014-12-01

    A consolidated study of the VUV absorption spectra of CH2Cl2 and CD2Cl2 in the 50,000-95,000 cm-1 region using synchrotron radiation is presented. Rydberg series and vibronic analysis are carried out and supported by quantum chemical calculations. The broad absorption band of CH2Cl2 in the region 50,000-60,000 cm-1 is attributed to the valence states 11B2, 11B1 and 11A1. Most of the bands in the 60,000-95,000 cm-1 region are fitted to Rydberg series of ns, np and nd type converging to the first four ionization potentials 11.320, 11.357, 12.152 and 12.271 eV of CH2Cl2 arising from excitation of an electron from one of the four outermost Cl non-bonding orbitals (2b1, 3b2, 1a2 and 4a1). Vertical excited states of CH2Cl2 calculated using TDDFT are correlated with experimentally observed electronic states based on the symmetries of the initial and final MOs involved in a transition. A few Rydberg transitions viz. 2b1→5s, 4p, 5p, 6p; 3b2→4p, 5p; 1a2→4p are accompanied by vibronic features. Observed vibronic bands are assigned mainly to the CCl symmetric stretch (ν3‧) mode with smaller contributions from the CH symmetric stretch (ν1‧), CH2 bend (ν2‧) and CH2 wag (ν8‧) modes. Assignments are corroborated by comparison with the VUV absorption spectrum of the deuterated isotopologue CD2Cl2, reported here for the first time. The high underlying intensities seen in several sub-regions are explained by valence or valence-Rydberg mixed type transitions predicted with high oscillator strengths by the TDDFT calculations.

  12. Ultraviolet radiation exposure from UV-transilluminators.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Jahangir-Blourchian, Mahdi

    2005-10-01

    UV-transilluminators use ultraviolet radiation (UVR) to visualize proteins, DNA, RNA, and their precursors in a gel electrophoresis procedure. This study was initiated to evaluate workers' exposure to UVR during their use of UV-transilluminators. The levels of irradiance of UV-A, UV-B, and UV-C were determined for 29 UV-transilluminators at arbitrary measuring locations of 6, 25, 62, and 125 cm from the center of the UV-transilluminator's filter surface in the direction of the operator's head. The operators (faculty, research staff, and graduate students) worked within 62 cm of the transilluminators, with most subjects commonly working at time ranged from 1 to 60 min. Actinic hazard (effective irradiance level of UVR) was also determined for three representative UV-transilluminators at arbitrary measuring locations of 2.5, 5, 10, 15, 20, 30, 40, and 50 cm from these sets' filter surface in the direction of the operator's head. The allowable exposure time for these instruments was less than 20 sec within 15 cm, less than 35 sec within 25 cm, and less than 2 min within 50 cm from the UV-transilluminators' filter surface. The results of this study suggest that the use of UV-transilluminators exposes operators to levels of UVR in excess of exposure guidelines. It is recommended that special safety training be provided for the affected employees and that exposure should be controlled by one or the combination of automation, substitution, isolation, posted warning signs, shielding, and/or personal protective equipment.

  13. UV-Vis Ratiometric Resonance Synchronous Spectroscopy for Determination of Nanoparticle and Molecular Optical Cross Sections.

    Science.gov (United States)

    Nettles, Charles B; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao

    2016-03-01

    Demonstrated herein is a UV-vis Ratiometric Resonance Synchronous Spectroscopic (R2S2, pronounced as "R-two-S-two" for simplicity) technique where the R2S2 spectrum is obtained by dividing the resonance synchronous spectrum of a NP-containing solution by the solvent resonance synchronous spectrum. Combined with conventional UV-vis measurements, this R2S2 method enables experimental quantification of the absolute optical cross sections for a wide range of molecular and nanoparticle (NP) materials that range optically from pure photon absorbers or scatterers to simultaneous photon absorbers and scatterers, simultaneous photon absorbers and emitters, and all the way to simultaneous photon absorbers, scatterers, and emitters in the UV-vis wavelength region. Example applications of this R2S2 method were demonstrated for quantifying the Rayleigh scattering cross sections of solvents including water and toluene, absorption and resonance light scattering cross sections for plasmonic gold nanoparticles, and absorption, scattering, and on-resonance fluorescence cross sections for semiconductor quantum dots (Qdots). On-resonance fluorescence quantum yields were quantified for the model molecular fluorophore Eosin Y and fluorescent Qdots CdSe and CdSe/ZnS. The insights and methodology presented in this work should be of broad significance in physical and biological science research that involves photon/matter interactions.

  14. Plant responses to UV-B irradiation are modified by UV-A irradiation

    International Nuclear Information System (INIS)

    Middleton, E.M.; Teramura, A.H.

    1993-01-01

    The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

  15. Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

    Science.gov (United States)

    Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

    2018-03-01

    Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

  16. UV photodissociation spectroscopy of oxidized undecylenic acid films.

    Science.gov (United States)

    Gomez, Anthony L; Park, Jiho; Walser, Maggie L; Lin, Ao; Nizkorodov, Sergey A

    2006-03-16

    Oxidation of thin multilayered films of undecylenic (10-undecenoic) acid by gaseous ozone was investigated using a combination of spectroscopic and mass spectrometric techniques. The UV absorption spectrum of the oxidized undecylenic acid film is significantly red-shifted compared to that of the initial film. Photolysis of the oxidized film in the tropospheric actinic region (lambda > 295 nm) readily produces formaldehyde and formic acid as gas-phase products. Photodissociation action spectra of the oxidized film suggest that organic peroxides are responsible for the observed photochemical activity. The presence of peroxides is confirmed by mass-spectrometric analysis of the oxidized sample and an iodometric test. Significant polymerization resulting from secondary reactions of Criegee radicals during ozonolysis of the film is observed. The data strongly imply the importance of photochemistry in aging of atmospheric organic aerosol particles.

  17. Long-term variability and impact on human health of biologically active UV radiation in Moscow

    Science.gov (United States)

    Zhdanova, Ekaterina; Chubarova, Natalia

    2014-05-01

    Measurements of erythemally weighted UV irradiance (Qer) have been performed at the Meteorological Observatory of Moscow State University since 1999 with the UVB-1 YES pyranometers. These types of devices are broadband with a spectral sensitivity curve close to the action spectrum of erythema. Main uncertainties of UVB-1 YES measurements include the difference in spectral curves of the instrument and the action spectrum of erythema, as well as the deviation from the cosine law. These uncertainties were taken into account in the database of Qer measurements (Chubarova, 2008. Additional corrections of UVB-1 measurements at low ambient temperatures have been made. We analyze interannual, seasonal and diurnal Qer changes over the time period 1999-2012. In addition, the comparisons with the results of UV reconstruction model (Chubarova, 2008) are made. This model allows us to evaluate relative changes in Qer due to variations in total ozone, effective cloud amount transmission, aerosol and cloud optical thickness since 1968. It is important to note that the main reason for UV irradiance monitoring development is the strong influence of UV irradiance on the biosphere and especially on human health mainly on human skin (CIE, 1993, CIE, 2006) and eyes (Oriowo, M. et al., 2001). Based on the detailed studies we have shown the possibility of utilizing UVB-1 pyranometers for measuring the eye-damage UV radiation. Parallel measurements by the Bentham DTM-300 spectrometer and the UVB-1 YES pyranometer at the Innsbruck Medical University (Austria) have provided us the calibration factor in eye-damage units for this broadband instrument. Influence of main geophysical factors on different types of UV irradiance is estimated by means the RAF ideology (Booth, Madronich, 1994). We discuss the responses of different types of biologically active UV radiation to the impact of various atmospheric factors. The UV conditions (deficiency, optimum, excess for human) are analyzed according to

  18. Looking at Art in the IR and UV

    Science.gov (United States)

    Falco, Charles

    2013-03-01

    Starting with the very earliest cave paintings art has been created to be viewed by the unaided eye and, until very recently, it wasn't even possible to see it at wavelengths outside the visible spectrum. However, it is now possible to view paintings, sculptures, manuscripts, and other cultural artifacts at wavelengths from the x-ray, through the ultraviolet (UV), to well into the infrared (IR). Further, thanks to recent advances in technology, this is becoming possible with hand-held instruments that can be used in locations that were previously inaccessible to anything but laboratory-scale image capture equipment. But, what can be learned from such ``non-visible'' images? In this talk I will briefly describe the characteristics of high resolution UV and IR imaging systems I developed for this purpose by modifying high resolution digital cameras. The sensitivity of the IR camera makes it possible to obtain images of art ``in situ'' with standard museum lighting, resolving features finer than 0.35 mm on a 1.0x0.67 m painting. I also have used both it and the UV camera in remote locations with battery-powered illumination sources. I will illustrate their capabilities with images of various examples of Western, Asian, and Islamic art in museums on three continents, describing how these images have revealed important new information about the working practices of artists as famous as Jan van Eyck. I also will describe what will be possible for this type of work with new capabilities that could be developed within the next few years. This work is based on a collaboration with David Hockney, and benefitted from image analys research supported by ARO grant W911NF-06-1-0359-P00001.

  19. Radioactive decontamination through UV laser

    International Nuclear Information System (INIS)

    Delaporte, Ph.; Gastaud, M.; Sentis, M.; Uteza, O.; Marine, W.; Thouvenot, P.; Alcaraz, J.L.; Le Samedy, J.M.; Blin, D.

    2003-01-01

    A device allowing the radioactive decontamination of metal surfaces through the use of a pulsed UV laser has been designed and tested. This device is composed of a 1 kW excimer laser linked to a bundle of optic fibers and of a system to recover particles and can operate in active zones. Metal surfaces have the peculiarities to trap radio-elements in a superficial layer of oxide that can be eaten away by laser radiation. Different contaminated metals (stainless steels, INCONEL and aluminium) issued from the nuclear industry have been used for the testing. The most important contaminants were 60 Co, 137 Cs, 154-155 Eu and 125 Sb. The ratio of decontamination was generally of 10 and the volume of secondary wastes generating during the process was very low compared with other decontamination techniques. A decontamination speed of 1 m 2 /h has been reached for aluminium. The state of the surface is an important parameter because radio-elements trapped in micro-cracks are very difficult to remove. (A.C.)

  20. Surface Coating of Musa Brachycarpa Trunk Using UV-Radiation

    International Nuclear Information System (INIS)

    Danu, Sugiarto; Sumarni, Anik; Nurhadi, Agus; Puspita, Rita

    2000-01-01

    An experiment on UV-curing of surface coating of Musa brachycarpa was carried out using urethane acrylate polymer films. Radiation curable material was the mixture of urethane acrylate resin, tripropylene glycol diacrylate monomer (TPGDA) and radical photo initiator of 2,2-dimethyl -2-hydroxy acetophenone. The TPGDA concentrations in the mixture with urethane acrylate resin were 60; 70 and 80% weight, Whereas concentrations of photo initiator were varied at the level 1.5:2.0 and 2.5% by weight based on resin and monomer mixture. Irradiation was conducted by using 80 Watt/cm intensity UV-light at the conveyor speed of 2: 3 and 4 m/min. Analysis and film properties observed were IR spectrum, gel fraction, hardness, abrasion resistance, glossy and chemical, solvent and stain resistances. Films have good resistances against 1% sodium carbonate, 5% acetic acid, 50% alcohol, thinner and red, blue and black permanent marker, except against 10% sodium hydroxide and 10% sulfuric acid. Optimum condition was achieved at the photo initiator concentration level of 2% and conveyor speed of 3 m/min

  1. Trade-off between camouflage and sexual dimorphism revealed by UV digital imaging: the case of Australian Mallee dragons (Ctenophorus fordi).

    Science.gov (United States)

    Garcia, Jair E; Rohr, Detlef; Dyer, Adrian G

    2013-11-15

    Colour patterns displayed by animals may result from the balance of the opposing requirements of sexual selection through display and natural selection through camouflage. Currently, little is known about the possibility of the dual purpose of an animal colour pattern in the UV region of the spectrum, which is potentially perceivable by both predators and conspecifics for detection or communication purposes. Here, we implemented linearised digital UV photography to characterise and quantify the colour pattern of an endemic Australian Agamid lizard classically regarded as monomorphic when considering data from the visible region of the spectrum. Our results indicate a widespread presence of UV elements across the entire body of the lizards and these patterns vary significantly in intensity, size and frequency between sexes. These results were modelled considering either lizard or avian visual characteristics, revealing that UV reflectance represents a trade-off between the requirements of sexual displaying to conspecifics and concealment from avian predators.

  2. Role of UV light in photodamage, skin aging, and skin cancer: importance of photoprotection.

    Science.gov (United States)

    Gonzaga, Evelyn R

    2009-01-01

    Solar, and particularly UV, radiation causes molecular and cellular damage with resultant histopathologic and clinical degenerative changes, leading in turn to photosensitivity, photo-aging, and skin cancer. While our bodies have some natural UV defenses, additional protection from the sun is essential, including sun avoidance, physical protection, and sunscreen use. Sun avoidance includes limiting exposure during peak UV times (10am-4pm), avoiding UV-reflective surfaces such as sand, snow and water, and eliminating photosensitizing drugs. Physical protection includes wearing photoprotective clothing such as a broad-brimmed hat and long sleeves and use of UV-blocking films on windows. Sunscreen containing avobenzone, titanium dioxide, zinc oxide or encamsule should be used daily and frequently reapplied. To guard against the UVB spectrum, zinc oxide and titanium dioxide are particularly recommended. Sunscreen is generally under-applied at only 25% of the recommended dose, seriously compromising photoprotection. Dosage guidelines recommend using more than half a teaspoon each on head and neck area and each arm, and more than a teaspoon each on anterior torso, posterior torso, and each leg (approximately 2 mg/cm(2)).

  3. Induction of DNA-protein crosslinks in human cells by ultraviolet and visible radiations: action spectrum

    International Nuclear Information System (INIS)

    Peak, J.G.; Peak, M.J.; Sikorski, R.S.; Jones, C.A.

    1985-01-01

    DNA-protein crosslinking was induced in cultured human P3 teratocarcinoma cells by irradiation with monochromatic radiation with wavelengths in the range 254-434 nm (far-UV, near-UV, and blue light). Wavelength 545 nm green light did not induce these crosslinks, using the method of alkaline elution of the DNA from membrane filters. The action spectrum for the formation of DNA-protein crosslinks revealed two maxima, one in the far-UV spectrum that closely coincided with the relative spectrum of DNA at 254 and 290 nm, and one in the visible light spectrum at 405 nm, which has no counterpart in the DNA spectrum. The primary events for the formation of DNA-protein crosslinks by such long-wavelength radiation probably involve photosensitizers. This dual mechanism for DNA-protein crosslink formation is in strong contrast to the single mechanism for pyrimidine dimer formation in DNA, which apparently has no component in the visible light spectrum

  4. Variability of pre-vitamin D3 effectiveness of UV appliances for skin tanning.

    Science.gov (United States)

    Sayre, Robert M; Dowdy, John C; Shepherd, James G

    2010-07-01

    While there is limited documentation that certain indoor tanning lamps effectively produce vitamin D, the diversity of such devices has not been extensively surveyed. This study compares the spectral effectiveness of a variety of tanning units, and solar spectra, for ultraviolet (UV) photosynthesis of pre-vitamin D3 (preD3) and UV induced erythema. Well-established techniques exist for the calculation of spectral effectiveness for photobiological responses that have defined action spectra. Using spectroradiometric data from sunlamp measurements, and standard solar reference spectra, we computed effective irradiances using the CIE action spectrum for the production of preD3 in human skin and the ISO/CIE human erythema reference action spectrum. We found, as with sunlight at different times or latitude, the preD3 and erythemal effectiveness of sunlamps varied as a function of the UV-B proportion of the spectrum. Ratios of sunlamp preD3 to erythemal effectiveness ranged from approximately 0.5 to nearly 2.0, similar to ratios for sunlight. Optimal risk to benefit conditions for preD3 from solar UV exposure occurs under high solar altitude, low zenith angle, midday midsummer sunlight. Analogous optimal preD3 exposure conditions are provided by low to intermediate pressure sunlamps with greater UV-B spectral overlap with the preD3 action spectrum. Similar to low altitude or high latitude sunlight, high pressure tanning units, filtered for negligible UV-B emissions, have insignificant vitamin D benefit. We conclude that while vitamin D can be made by both UVB exposure from indoor tanning units and by exposure UVB from sunlight, the effect is also comparably variable. Unlike sunlight, indoor tanning offers privacy and environmental conditions for practical full body exposure, lowering the requisite exposure per skin surface area, and device timers limit the potential of overexposure. Guidance for optimal use of tanning sources for vitamin D benefit is needed. Copyright (c

  5. Application of UV Imaging in Formulation Development

    DEFF Research Database (Denmark)

    Sun, Yu; Østergaard, Jesper

    2017-01-01

    defining formulation behavior after exposure to the aqueous environments and pharmaceutical performance is critical in pharmaceutical development, manufacturing and quality control of drugs. UV imaging has been explored as a tool for qualitative and quantitative characterization of drug dissolution...... related to the structural properties of the drug substance or formulation can be monitored. UV imaging is a non-intrusive and simple-to-operate analytical technique which holds potential for providing a mechanistic foundation for formulation development. This review aims to cover applications of UV...

  6. Global Solar UV Index (invited paper)

    International Nuclear Information System (INIS)

    Repacholi, M.H.

    2000-01-01

    Excessive solar ultraviolet (UV) radiation exposure produces a significant burden of disease to the skin, eyes and immune system. Effective programmes for the reduction of UV exposure are needed to reduce this disease burden and the associated health care costs. The UV index is seen as an effective tool for communicating important protection information to the public through its use in media news and weather information. The index is described and it is suggested that universally common messages should be associated with its ranges. (author)

  7. RPC industries - UV and EB equipment manufacturers

    International Nuclear Information System (INIS)

    Rodrigues, A.M.

    1987-01-01

    RPC Industries has been manufacturing electron beam and ultraviolet equipment for the industrial processing of materials for more than 15 years. RPC maintains its headquarters and electron processor manufacturing plant in Hayward, California. UV equipment is made in the company's plant near Chicago. Sales offices are maintained in New York, Illinois, and California in the USA, and in Germany, Japan, Australia, Italy, Israel, and Sweden. Complete testing and pilot facilities are available in Hayward (EB) and near Chicago (UV). Described below are the basic system components, applications and advantages of RPC's UV and EB systems. (orig.)

  8. Real time spectrum analysis

    International Nuclear Information System (INIS)

    Blunden, A.; O'Prey, D.G.; Tait, W.H.

    1983-01-01

    A method is described for the separation of a composite pulse-height spectrum into its unresolved component parts, which belong to a set of measured library spectra. The method allows real-time estimation giving running estimates during acquisition of the spectrum, minimises computation space, especially for a number of parallel calculations, estimates in advance the rms errors, and produces a significance measure for the hypothesis that the composite contains only the library spectra. Least squares curve-fitting, and other methods, can be compared, with the formalism developed, allowing analytical comparison of the effect of detector energy resolution and detection efficiency. A rational basis for the choice between the various methods of spectrum analysis follows from the theory, minimising rms estimation errors. The method described is applicable for very low numbers of counts and poor resolution. (orig.)

  9. Neuromyelitis Optica Spectrum Disorders.

    Science.gov (United States)

    Akaishi, Tetsuya; Nakashima, Ichiro; Sato, Douglas Kazutoshi; Takahashi, Toshiyuki; Fujihara, Kazuo

    2017-05-01

    Neuromyelitis optica (NMO) is clinically characterized by severe optic neuritis and transverse myelitis, but recent studies with anti-aquaporin-4-antibody specific to NMO have revealed that the clinical spectrum is wider than previously thought. International consensus diagnostic criteria propose NMO spectrum disorders (NMOSD) as the term to define the entire spectrum including typical NMO, optic neuritis, acute myelitis, brain syndrome, and their combinations. NMOSD is now divided into anti-aquaporin-4-antibody-seropositive NMOSD and -seronegative NMOSD (or unknown serostatus). MR imaging and optical coherence tomography are indispensable in the diagnosis and evaluation of NMOSD. This article reviews the clinical and MR imaging findings of anti-aquaporin-4-antibody-seropositive and anti-myelin oligodendrocyte glycoprotein-antibody-seropositive NMOSD. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Transformation of UV-hypersensitive Chinese hamster ovary cell mutants with UV-irradiated plasmids

    International Nuclear Information System (INIS)

    Nairn, R.S.; Humphrey, R.M.; Adair, G.M.

    1988-01-01

    Transfection of UV-hypersensitive, DNA repair-deficient Chinese hamster ovary (CHO) cell lines and parental, repair-proficient CHO cells with UV-irradiated pHaprt-1 or pSV2gpt plasmids resulted in different responses by recipient cell lines to UV damage in transfected DNA. Unlike results reported for human cells, UV irradiation of transfecting DNA did not stimulate genetic transformation of CHO recipient cells. In repair-deficient CHO cells, proportionally fewer transformants were produced with increasing UV damage than in repair-proficient cells in transfections with UV-irradiated hamster adenine phosphoribosyltransferase (APRT) gene contained in plasmid pHaprt-1. Transfection of CHO cells with UV-irradiated pSV2gpt resulted in neither decline in transformation frequencies in repair-deficient cell lines relative to repair-proficient cells nor stimulation of genetic transformation by UV damage in the plasmid. Blot hybridization analysis of DNA samples isolated from transformed cells showed no dramatic changes in copy number or arrangement of transfected plasmid DNA with increasing UV dose. The authors conclude responses of recipient cells to UV-damaged transfecting plasmids depend on type of recipient cell and characteristics of the genetic sequence used for transfection. (author)

  11. Spectrum and Structure of Spiropyran

    National Research Council Canada - National Science Library

    Young, J

    1994-01-01

    .... Both quantum mechanical and classical methods were used. Irradiation of spiropyran by UV light causes molecular rearrangement, thus yielding merocyanine whose absorption band lies in the visible region...

  12. Bottomonium spectrum revisited

    CERN Document Server

    Segovia, Jorge; Entem, David R.; Fernández, Francisco

    2016-01-01

    We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way to determine their properties experimentally.

  13. New technology and application in UV curing

    International Nuclear Information System (INIS)

    Loutz, J.M.

    1999-01-01

    Overview of radcure technology was presented. Its included this following subjects, radiation curable powder coatings, UV curable water based polyurethanes, photo-initiators, fire retardancy, aqueous systems, cationic, ceramic and optical grade material

  14. Effect of UV irradiation on cutaneous cicatrices

    DEFF Research Database (Denmark)

    Due, Eva; Rossen, Kristian; Sorensen, Lars Tue

    2007-01-01

    The aim of this study was to examine the effect of ultraviolet (UV) irradiation on human cutaneous cicatrices. In this randomized, controlled study, dermal punch biopsy wounds served as a wound healing model. Wounds healed by primary or second intention and were randomized to postoperative solar UV...... postoperatively, UV-irradiated cicatrices healing by second intention: (i) were significantly pointed out as the most disfiguring; (ii) obtained significantly higher scores of colour, infiltration and cicatrix area; and (iii) showed significantly higher increase in skin-reflectance measurements of skin......-pigmentation vs. non-irradiated cicatrices. No histological, immunohistochemical or biochemical differences were found. In conclusion, postoperative UV exposure aggravates the clinical appearance of cicatrices in humans....

  15. UV curable palm oil based ink

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Mohd Hilmi Mahmood; Khairul Zaman Mohd Dahlan; Rosley Che Ismail

    2002-01-01

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil urethane acrylate (POBUA) as a prepolymer in the UV ink system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  16. UV curable palm oil based inks

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Hilmi Mahmood

    2002-01-01

    UV curable inks are useful for their instant drying, energy saving and high productivity properties. The basic materials for formulating UV curable inks consist of prepolymer, monomers, photoinitiators, pigments and other additives. The percentage composition and ingredients depend very much on the types of inks to be produced. Palm oil is one of the main raw materials available in the country. Hence, the diversification of palm oil derivatives into new products has been given priority. The current focus of the present work is to evaluate the use of palm oil based urethane acrylate (POBUA) as a prepolymer in the UV inks system. A study was conducted on the use of POBUA with other materials in ink formulation. These include the types and concentration of photoinitiators, monomers and commercial urethane acrylates. The evaluation of the ink properties such as curing, adhesion, color density have been carried out. It was found that POBUA could be introduced in the UV ink system. (Author)

  17. Accelerated Solar-UV Test Chamber

    Science.gov (United States)

    Gupta, A.; Laue, E. G.

    1984-01-01

    Medium-pressure mercury-vapor lamps provide high ratio of ultraviolet to total power. Chamber for evaluating solar-ultraviolet (UV) radiation damage permits accelerated testing without overheating test specimens.

  18. UV filters for lighting of plants

    Energy Technology Data Exchange (ETDEWEB)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H.K.; Payer, H.D. [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany)

    1994-12-31

    Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The ageing of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

  19. Road Signs for UV-Completion

    CERN Document Server

    Dvali, Gia; Gomez, Cesar

    2012-01-01

    We confront the concepts of Wilsonian UV-completion versus self-completion by Classicalization in theories with derivatively-coupled scalars. We observe that the information about the UV-completion road is encoded in the sign of the derivative terms. We note that the sign of the derivative couplings for which there is no consistent Wilsonian UV-completion is the one that allows for consistent classicalons. This is an indication that for such a sign the vertex must be treated as fundamental and the theory self-protects against potential inconsistencies, such as superluminality, via self-completion by classicalization. Applying this reasoning to the UV-completion of the Standard Model, we see that the information about the Higgs versus classicalization is encoded in the sign of the scattering amplitude of longitudinal W-bosons. Negative sign excludes Higgs or any other weakly-coupled Wilsonian physics.

  20. Mean Annual UV-B Irradiance

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ultraviolet-B (UV-B) radiation is the most energetic part of sunlight reaching the Earth's surface (wavelength region is 280 to 315 nm), and it has been shown to...

  1. UV Impacts Avoided by the Montreal Protocol

    Science.gov (United States)

    Newman, Paul; McKenzie, Richard

    2010-01-01

    Temporal and geographical variabilities in the future "World Expected" UV environment are compared with the "World Avoided", which would have occurred without the Montreal Protocol on protection of the ozone layer and its subsequent amendments and adjustments. Based on calculations of clear-sky UV irradiances, the effects of the Montreal Protocol have been hugely beneficial to avoid the health risks, such as skin cancer, which are associated with high UV, while there is only a small increase in health risks, such as vitamin D deficiency, that are associated with low UV. However, interactions with climate change may lead to changes in cloud and albedo, and possibly behavioural changes which could also be important.

  2. Progress in deep-UV photoresists

    Indian Academy of Sciences (India)

    Unknown

    This paper reviews the recent development and challenges of deep-UV photoresists and their ... small amount of acid, when exposed to light by photo- chemical ... anomalous insoluble skin and linewidth shift when the. PEB was delayed.

  3. Remote UV Fluorescence Lifetime Spectrometer, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop, demonstrate, and deliver to NASA an innovative, portable, and power efficient Remote UV Fluorescence Lifetime Spectrometer...

  4. UV sensitivity of various solid state detectors

    International Nuclear Information System (INIS)

    Knezevic, Zeljka; Ranogajec-Komor, Maria; Miljanic, Saveta

    2008-01-01

    Full text: The light sensitivity is an important characteristic of solid state passive dosimeters used in individual, clinical and environmental dosimetry. Light sensitivity stands for the response directly induced by visible or UV light in a fully annealed material. For the above mentioned applications a negligible light sensitivity is an advantage. However, high light sensitivity and linear response allows the use of detectors as UV dosimeters. For this purpose various TL detectors and the glass element of the RPL dosemeter type SC-1 were systematically investigated after exposure to UV light (254 and 366 nm) as a function of time. The following solid state detectors were investigated relative to TLD-100: Li 2 B 4 O 7 :Cu,Ag,P LiF:Mg,Cu,P, LiF:Mg,Cu,Si, Al 2 O 3 :C and the glass element of RPL dosimeter. UV irradiations were performed with Camag UV lamp at 254 nm and at 366 nm. The illumination times were 5, 10 and 20 minutes. Day light illumination was also carried out at room temperature over time period of several hours up to 2 weeks. The UV light response of each detector was compared to the response obtained after irradiation with 137 Cs. Al 2 O 3 :C, showed high light sensitivity; after 10 minutes illumination with 254 nm UV light the response was equivalent to 130 mGy 137 Cs gamma irradiation. The 254 nm UV response of LiF:Mg,Cu,P (GR-200 A), as well as TLD-700H and Li 2 B 4 O 7 :Cu,Ag,P were proportional to the time of illumination. The responses after 10 min UV illumination were equivalent to 0.001 mGy, 0.01 mGy and 0.1 mGy 137 Cs gamma irradiation, respectively. The complete SC-1 RPL dosimeter is insensitive to light because the glass element is encapsulated in light protected holder throughout the automatic evaluation process following the annealing (irradiation, preheat, readout). The responses of the previously annealed glass element after 20 min illumination with 254 nm and 366 nm UV light were equivalent to 45μSv and 3 μSv of 137 Cs gamma

  5. Dynamic Optimization of UV Flash Processes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Jørgensen, John Bagterp

    2017-01-01

    UV ash processes, also referred to as isoenergetic-isochoric ash processes, occur for dynamic simulation and optimization of vapor-liquid equilibrium processes. Dynamic optimization and nonlinear model predictive control of distillation columns, certain two-phase ow problems, as well as oil reser...... that the optimization solver, the compiler, and high-performance linear algebra software are all important for e_cient dynamic optimization of UV ash processes....

  6. Bactericidal effectiveness of modulated UV light

    International Nuclear Information System (INIS)

    Bank, H.L.; John, J.; Schmehl, M.K.; Dratch, R.J.

    1990-01-01

    Studies were designed to evaluate the effectiveness of pulsed modulated UV light waveforms for killing bacteria. Exposure of five strains of bacteria to the modulated information encoded in the light decreased the colony population from a confluent lawn to less than 20 colonies. However, approximately 2,000 colonies survived treatment with the same intensity and time of exposure to UV light lacking the modulated information

  7. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E; Thomalla, E; Koepke, P [Munich Univ. (Germany). Meteorological Inst.

    1996-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  8. UV spectra, bombs, and the solar atmosphere

    OpenAIRE

    Judge, Philip G.

    2015-01-01

    A recent analysis of UV data from the Interface Region Imaging Spectrograph {\\em IRIS} reports plasma "bombs" with temperatures near \\hot{} within the solar photosphere. This is a curious result, firstly because most bomb plasma pressures $p$ (the largest reported case exceeds $10^3$ dyn~cm$^{-2}$) fall well below photospheric pressures ($> 7\\times10^3$), and secondly, UV radiation cannot easily escape from the photosphere. In the present paper the {\\em IRIS} data is independently analyzed. I...

  9. Chronic effects of UV on human skin

    International Nuclear Information System (INIS)

    Cesarini, J.P.

    1996-01-01

    Chronic exposures and acute accidents of the skin to UV has been recognized as an important risk for skin cancers in human. Attempts have been made with mathematical models to correlate the ambient UV dose and occupational irradiations with the risk of skin cancers. Development of accurate global measurements of solar irradiance and personal dosimetry is expected in the future in order to reduce the exposure of the general population, to precise the measures to be taken for indoor and outdoor workers. (author)

  10. UV written compact broadband optical couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques.......In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques....

  11. UV written 1x8 optical splitters

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed.......In this paper the first demonstration of 1x8 optical power splitters made by direct UV writing is presented. Design and optimization of the process as well as the performance of the fabricated components are discussed....

  12. Accurate modeling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  13. Accurate modelling of UV written waveguide components

    DEFF Research Database (Denmark)

    Svalgaard, Mikael

    BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure.......BPM simulation results of UV written waveguide components that are indistinguishable from measurements can be achieved on the basis of trajectory scan data and an equivalent step index profile that is very easy to measure....

  14. From ozone depletion to biological UV damage

    Energy Technology Data Exchange (ETDEWEB)

    Tamm, E.; Thomalla, E.; Koepke, P. [Munich Univ. (Germany). Meteorological Inst.

    1995-12-31

    Based on the ozone data from the Meteorological Observatory Hohenpeissenberg (MOHP: 47.8 deg N, 11.01 deg E) and corresponding mean atmospheric conditions, high resolution UV spectra are calculated with a complex radiation transfer model STAR. Biologically weighted UV spectra are investigated as integrated irradiances (dose rates) for maximum zenith angles and as daily integrals for selected days of the year. Ozone variation and uncertainty of action spectra are investigated

  15. Reconstructing Neutrino Mass Spectrum

    OpenAIRE

    Smirnov, A. Yu.

    1999-01-01

    Reconstruction of the neutrino mass spectrum and lepton mixing is one of the fundamental problems of particle physics. In this connection we consider two central topics: (i) the origin of large lepton mixing, (ii) possible existence of new (sterile) neutrino states. We discuss also possible relation between large mixing and existence of sterile neutrinos.

  16. Autism Spectrum Disorder

    Centers for Disease Control (CDC) Podcasts

    2014-04-02

    This podcast discusses autism spectrum disorder (ASD), a developmental disability that causes problems with social, communication, and behavioral skills. CDC estimates that one in 68 children has been identified as having ASD.  Created: 4/2/2014 by National Center on Birth Defects and Developmental Disabilities (NCBDDD).   Date Released: 4/2/2014.

  17. Strategic Vision for Spectrum

    Science.gov (United States)

    2010-01-01

    maneuverable, flexible , and tactically effective. In the last few years, the rapid adoption of commercial communication tech- nologies has taxed...Logistics. The foundation that supports the mobility, flexibility , and precision necessary to accomplish these goals is the electromagnetic spectrum. 2...eGovernment, Enterprise Knowledge, Enterprise Licensing, Information Assurance, Librarian of the Navy, Organizational eLearning , Planning and Measurement

  18. Aluminum nitride integrated photonics platform for the ultraviolet to visible spectrum.

    Science.gov (United States)

    Lu, Tsung-Ju; Fanto, Michael; Choi, Hyeongrak; Thomas, Paul; Steidle, Jeffrey; Mouradian, Sara; Kong, Wei; Zhu, Di; Moon, Hyowon; Berggren, Karl; Kim, Jeehwan; Soltani, Mohammad; Preble, Stefan; Englund, Dirk

    2018-04-30

    We demonstrate a wide-bandgap semiconductor photonics platform based on nanocrystalline aluminum nitride (AlN) on sapphire. This photonics platform guides light at low loss from the ultraviolet (UV) to the visible spectrum. We measure ring resonators with intrinsic quality factor (Q) exceeding 170,000 at 638 nm and Q >20,000 down to 369.5 nm, which shows a promising path for low-loss integrated photonics in UV and visible spectrum. This platform opens up new possibilities in integrated quantum optics with trapped ions or atom-like color centers in solids, as well as classical applications including nonlinear optics and on-chip UV-spectroscopy.

  19. Photodegradation and toxicity changes of antibiotics in UV and UV/H2O2 process

    International Nuclear Information System (INIS)

    Yuan Fang; Hu Chun; Hu Xuexiang; Wei Dongbin; Chen Yong; Qu Jiuhui

    2011-01-01

    The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H 2 O 2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H 2 O 2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R OH,UV , defined as the experimentally determined ·OH radical exposure per UV fluence. The R OH,UV values represent the background ·OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H 2 O 2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H 2 O 2 process was identified using GC-MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H 2 O 2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of ·OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H 2 O 2 process would be determined by parent compound degradation and toxicity changes.

  20. DNA repair of UV photoproducts and mutagenesis in human mitochondrial DNA

    International Nuclear Information System (INIS)

    Pascucci, B.; Dogliotti, E.; Versteegh, A.; Hoffen, A. van; Zeeland, A.A. van; Mullenders, L.H.F.

    1997-01-01

    The induction and repair of DNA photolesions and mutations in the mitochondrial (mt) DNA of human cells in culture were analysed after cell exposure to UV-C light. The level of induction of cyclobutane pyrimidine dimers (CPD) in mitochondrial and nuclear DNA was comparable, while a higher frequency of pyrimidine (6-4) pyrimidone photoproducts (6-4 PP) was detected in mitochondrial than in nuclear DNA. Besides the known defect in CPD removal, mitochondria were shown to be deficient also in the excision of 6-4 PP. The effects of repair-defective conditions for the two major UV photolesions on mutagensis was assessed by analysing the frequency and spectrum of spontaneous and UV-induced mutations by restriction site mutation (RSM) method in a restriction endonuclease site, NciI (5'CCCGG3') located within the coding sequence of the mitochondrial gene for tRNA Leu . The spontaneous mutation frequency and spectrum at the NciI site of mitochondrial DNA was very similar to the RSM background mutation frequency (approximately 10 -5 ) and type (predominantly GC > AT transitions at GL 1 ) of the NciI site). Conversely, an approximately tenfold increase over background mutation frequency was recorded after cell exposure to 20 J/m 2 . In this case, the majority of mutations were C > T transitions preferentially located on the non-transcribed DNA strand at C 1 and C 2 of the NciI site. This mutation spectrum is expected by UV mutagenesis. This is the first evidence of induction of mutations in mitochondrial DNA by treatment of human cells with a carcinogen. (author)

  1. A study on UV irradiated HDPE

    International Nuclear Information System (INIS)

    Sang Haibo; Liu Zimin; Wu Shishan; Shen Jian

    2006-01-01

    The structure and properties of HDPE irradiated by ultraviolet (UV) in ozone atmosphere were studied by FT-IR, XPS, gel, and water contact angle test. The oxygen-containing groups such as C=O, C-O and C(=O)O were introduced onto high density polyethylene (HDPE) chains through ultraviolet irradiation in ozone atmosphere, their content increased with the UV irradiation time. Under the same UV irradiation conditions, amount of the oxygen-containing groups introduced in ozone atmosphere was more than that in air atmosphere, indicating that the speed of oxygen-containing groups introduced through UV irradiation in ozone atmosphere was faster than that in air. Therefore, HDPE could be quickly functionalized through UV irradiation in ozone atmosphere. There was no gel formed in the HDPE irradiated in ozone atmosphere. After UV irradiation, the water contact angle of HDPE decreased, and its hydrophilicity was improved, suggesting that the compatibility between the irradiated HDPE and polar polymer or inorganic fillers may be better. Compared with HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The structure and properties of irradiated HDPE/CaCO 3 blend were also investigated. The results showed that the compatibility and interfacial action of the irradiated HDPE/CaCO 3 blend were improved compared to that of HDPE/CaCO 3 blend. The mechanical properties of irradiated HDPE/CaCO 3 blend increased with increasing irradiation time. (authors)

  2. Impact of fouling on UV effectiveness

    International Nuclear Information System (INIS)

    Dykstra, T.S.; Chauret, C.

    2002-01-01

    In recent years ultraviolet light has gained in popularity as an attractive disinfection alternative due to its ability to inactivate bacteria and viruses. UV light has the potential to inactivate Cryptosporidium parvum and Giardia lamblia with a very low potential for the formation of harmful disinfection by-products. Previous studies have reported that particulate material present in the water can act to reduce the exposure of UV light to the receiving waters and that the interference of organic particles can serve to protect bacteria and viruses from intended disinfection. Disinfection capacity can also be reduced by organics in the source water that can accumulate on the surface of quartz sleeves. The purpose of this study was to determine the ability of a medium pressure UV light, at drinking water treatment levels, to inactivate MS 2 bacteriophage after a quartz tube has been fouled with organic rich source water for a 12- week period. To this end the inactivation of MS 2 was determined under clean and fouled conditions, in the presence and absence of humic rich water. The effect of lamp age on inactivation was also investigated. The results suggest that organic fouling of a quartz tube has a significant impact on the disinfection capacity of a medium pressure UV lamp. The presence of organics in the source water also plays a significant role in reducing the capacity of UV for bacterial and viral disinfection. Lamp age also seems to have some effect on the efficiency of UV disinfection. (author)

  3. Light - Instead of UV Protection: New Requirements for Skin Cancer Prevention.

    Science.gov (United States)

    Zastrow, Leonhard; Lademann, Jürgen

    2016-03-01

    The requirements on sunscreens have essentially changed, since some years ago it was demonstrated that approximately 50% of free radicals, that are formed in the skin by solar radiation, originate from the visible and infrared regions of the solar spectrum. In addition, a critical radical concentration threshold could be found. If this concentration, the free radical threshold value (FRTV), is exceeded, sunburn, immunosuppression and skin cancer may develop. Application of sunscreens and lotions protects against sunburn in the UV region of the solar spectrum and therefore is frequently used to extend people's stay in the sun. However, this behaviour can enhance the concentration of free radicals formed in the visible and infrared regions of the solar spectrum, so that the critical radical threshold is exceeded and the skin may be damaged. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  4. UV-Vis, infrared, and mass spectroscopy of electron irradiated frozen oxygen and carbon dioxide mixtures with water

    International Nuclear Information System (INIS)

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-01-01

    Ozone has been detected on the surface of Ganymede via observation of the Hartley band through the use of ultraviolet spectroscopy and is largely agreed upon to be formed by radiolytic processing via interaction of magnetospheric energetic ions and/or electrons with oxygen-bearing ices on Ganymede's surface. Interestingly, a clearly distinct band near 300 nm within the shoulder of the UV-Vis spectrum of Ganymede was also observed, but currently lacks an acceptable physical or chemical explanation. Consequently, the primary motivation behind this work was the collection of UV-Vis absorption spectroscopy of ozone formation by energetic electron bombardment of a variety of oxygen-bearing ices (oxygen, carbon dioxide, water) relevant to this moon as well as other solar system. Ozone was indeed synthesized in pure ices of molecular oxygen, carbon dioxide and a mixture of water and oxygen, in agreement with previous studies. The Hartley band of the ozone synthesized in these ice mixtures was observed in the UV-Vis spectra and compared with the spectrum of Ganymede. In addition, a solid state ozone absorption cross section of 6.0 ± 0.6 × 10 –17 cm 2 molecule –1 was obtained from the UV-Vis spectral data. Ozone was not produced in the irradiated carbon dioxide-water mixtures; however, a spectrally 'red' UV continuum is observed and appears to reproduce well what is observed in a large number of icy moons such as Europa.

  5. Effect of UV irradiation on the apoptosis and necrosis of Jurkat cells using UV LEDs

    Science.gov (United States)

    Inada, Shunko A.; Amano, Hiroshi; Akasaki, Isamu; Morita, Akimichi; Kobayashi, Keiko

    2009-02-01

    Phototherapy is a very effective method for treating most of the incurable skin diseases. A fluorescent light bulb is used as a conventional UV light source for this type of therapy. However, infrared radiation from the light source sometimes causes serious problems on patient's health. In addition, the normal part of the skin is irradiated when a large fluorescent light bulb is used. Moreover, a conventional UV irradiation system is heavy and has a short lifetime and a high electrical power consumption. Therefore, a new UV light source for solving the problems of phototherapy is required. To realize low-power-consumption, lightweight and long-lifetime systems, group III nitride-based UV-A1 light-emitting diodes (LEDs) were investigated. We examined the UV LED irradiation of Jurkat cell, which is a tumor cell and more sensitive to UV light than a healthy cell. The numbers of apoptotic and necrotic cells were confirmed to be the same using a UV LED and a conventional lamp system. The UV LED showed the possibility of realizing a new UV light source for phototherapy.

  6. Effects of UV radiation on phytoplankton

    Science.gov (United States)

    Smith, Raymond C.; Cullen, John J.

    1995-07-01

    It is now widely documented that reduced ozone will result in increased levels of ultraviolet (UV) radiation, especially UV-B (280-320nm), incident at the surface of the earth [Watson, 1988; Anderson et al., 1991; Schoeberl and Hartmann, 1991; Frederick and Alberts, 1991; WMO, 1991; Madronich, 1993; Kerr and McElroy, 1993], and there is considerable and increasing evidence that these higher levels of UV-B radiation may be detrimental to various forms of marine life in the upper layers of the ocean. With respect to aquatic ecosystems, we also know that this biologically- damaging mid-ultraviolet radiation can penetrate to ecologically- significant depths in marine and freshwater systems [Jerlov, 1950; Lenoble, 1956; Smith and Baker, 1979; Smith and Baker, 1980; Smith and Baker, 1981; Kirk et al., 1994]. This knowledge, plus the dramatic decline in stratospheric ozone over the Antarctic continent each spring, now known to be caused by anthropogenically released chemicals [Solomon, 1990; Booth et al., 1994], has resulted in increased UV-environmental research and a number of summary reports. The United Nations Environmental Program (UNEP) has provided recent updates with respect to the effects of ozone depletion on aquatic ecosystems (Hader, Worrest, Kumar in UNEP 1989, 1991, Hader, Worrest, Kumar and Smith UNEP 1994) and the Scientific Committee on Problems of the Environment (SCOPE) has provided [SCOPE, 1992] a summary of the effects of increased UV radiation on biological systems. SCOPE has also reported [SCOPE, 1993] on the effects of increased UV on the biosphere. In addition, several books have recently been published reviewing various aspects of environmental UV photobiology [Young et al., 1993], UV effects on humans, animals and plants [Tevini, 1993], the biological effects of UV radiation in Antarctica [Weiler and Penhale, 1994], and UV research in freshwater ecosystems [Williamson and Zagarese, 1994]. Several other reviews are relevant [NAS, 1984; Caldwell

  7. Changes induced by UV radiation in the presence of sodium benzoate in films formulated with polyvinyl alcohol and carboxymethyl cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Villarruel, S. [Faculty of Exact Sciences, UNLP (Argentina); Giannuzzi, L.; Rivero, S. [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Pinotti, A., E-mail: acaimpronta@hotmail.com [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Faculty of Engineering, UNLP, La Plata 1900 (Argentina)

    2015-11-01

    This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), and iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of polymer–polymer interaction at a molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of microorganisms. From a physicochemical perspective, the UV treatment of films also changed their morphology rendering them more insoluble in water, turning the functionalized blend films into a potential material to be applied as food packaging. - Highlights: • CMC:PVOH blend films were developed with the addition of sodium benzoate (SB). • Exposition to UV radiation was carried out with sodium benzoate as photoinitiator. • Blend films were exposed to UV radiation to modify their surface morphology. • Low O{sub 2} permeability of UV treated blends allow them to be used as selective packaging. • Efficacy of SB as an antimicrobial agent was examined with and without UV radiation.

  8. Changes induced by UV radiation in the presence of sodium benzoate in films formulated with polyvinyl alcohol and carboxymethyl cellulose

    International Nuclear Information System (INIS)

    Villarruel, S.; Giannuzzi, L.; Rivero, S.; Pinotti, A.

    2015-01-01

    This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), and iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of polymer–polymer interaction at a molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of microorganisms. From a physicochemical perspective, the UV treatment of films also changed their morphology rendering them more insoluble in water, turning the functionalized blend films into a potential material to be applied as food packaging. - Highlights: • CMC:PVOH blend films were developed with the addition of sodium benzoate (SB). • Exposition to UV radiation was carried out with sodium benzoate as photoinitiator. • Blend films were exposed to UV radiation to modify their surface morphology. • Low O 2 permeability of UV treated blends allow them to be used as selective packaging. • Efficacy of SB as an antimicrobial agent was examined with and without UV radiation

  9. Optimizing UV Index determination from broadband irradiances

    Science.gov (United States)

    Tereszchuk, Keith A.; Rochon, Yves J.; McLinden, Chris A.; Vaillancourt, Paul A.

    2018-03-01

    A study was undertaken to improve upon the prognosticative capability of Environment and Climate Change Canada's (ECCC) UV Index forecast model. An aspect of that work, and the topic of this communication, was to investigate the use of the four UV broadband surface irradiance fields generated by ECCC's Global Environmental Multiscale (GEM) numerical prediction model to determine the UV Index. The basis of the investigation involves the creation of a suite of routines which employ high-spectral-resolution radiative transfer code developed to calculate UV Index fields from GEM forecasts. These routines employ a modified version of the Cloud-J v7.4 radiative transfer model, which integrates GEM output to produce high-spectral-resolution surface irradiance fields. The output generated using the high-resolution radiative transfer code served to verify and calibrate GEM broadband surface irradiances under clear-sky conditions and their use in providing the UV Index. A subsequent comparison of irradiances and UV Index under cloudy conditions was also performed. Linear correlation agreement of surface irradiances from the two models for each of the two higher UV bands covering 310.70-330.0 and 330.03-400.00 nm is typically greater than 95 % for clear-sky conditions with associated root-mean-square relative errors of 6.4 and 4.0 %. However, underestimations of clear-sky GEM irradiances were found on the order of ˜ 30-50 % for the 294.12-310.70 nm band and by a factor of ˜ 30 for the 280.11-294.12 nm band. This underestimation can be significant for UV Index determination but would not impact weather forecasting. Corresponding empirical adjustments were applied to the broadband irradiances now giving a correlation coefficient of unity. From these, a least-squares fitting was derived for the calculation of the UV Index. The resultant differences in UV indices from the high-spectral-resolution irradiances and the resultant GEM broadband irradiances are typically within 0

  10. Influence of uvA on the erythematogenic and therapeutic effects of uvB irradiation in psoriasis; photoaugmentation effects

    International Nuclear Information System (INIS)

    Boer, J.; Schothorst, A.A.; Suurmond, D.

    1981-01-01

    The effect of repeated exposure to an additive dose of long ultraviolet (uvA) radiation on the erythemogenic and therapeutic effects of middle ultraviolet (uvB) irradiation was investigated in 8 patients with psoriasis. The surface of the backs of these patients was divided into 2 parts, 1 of which received only uvB irradiation 4 times a week and the other uvA + uvB. uvB was provided by Philips TL-12 lamps and uvA by glass-filtered Philips TL-09 lamps. uvA was held constantly at 10 J/cm2, whereas uvB alone were evaluated by 4 tests during the treatment to determine the minimal erythema dose (MED). Test I (at the start of the therapy) showed a photoaugmentative effect which was no longer apparent in Test III (third week). Test III showed a reversal of the ratios of the MEDs of the sites irradiated with the uvA + uvB and uvB (MED A + B/MED B). This is ascribed to the marked pigmentation which appeared after repeated irradiation with the uvA + uvB combination. Comparison showed for the improvement of the psoriasis no distinct differences between uvA + uvB irradiation and uvB alone, but the former had the cosmetic advantage of giving pleasing tan

  11. A thirty percent increase in UV-B has no impact on photosynthesis in well-watered and droughted pea plants in the field

    International Nuclear Information System (INIS)

    Allen, D.J.; Nogues, S.; Morison, J.I.L.; Greenslade, P.D.; McLeod, A.R.; Baker, N.R.

    1999-01-01

    It has been suggested that field experiments which increase UV-B irradiation by a fixed amount irrespective of ambient light conditions (‘square-wave’), may overestimate the response of photosynthesis to UV-B irradiation. In this study, pea (Pisum sativum L.) plants were grown in the field and subjected to a modulated 30% increase in ambient UK summer UV-B radiation (weighted with an erythemal action spectrum) and a mild drought treatment. UV-A and ambient UV control treatments were also studied. There were no significant effects of the UV-B treatment on the in situ CO 2 assimilation rate throughout the day or on the light-saturated steady-state photosynthesis. This was confirmed by an absence of UV-B effects on the major components contributing to CO 2 assimilation; photosystem II electron transport, ribulose 1,5-bisphosphate regeneration, ribulose 1,5-bisphosphate carboxylase/oxygenase carboxylation, and stomatal conductance. In addition to the absence of an effect on photosynthetic activities, UV-B had no significant impact on plant biomass, leaf area or partitioning. UV-B exposure increased leaf flavonoid content. The UV-A treatment had no observable effect on photosynthesis or productivity. Mild drought resulted in reduced biomass, a change in partitioning away from shoots to roots whilst maintaining leaf area, but had no observable effect on photosynthetic competence. No UV-B and drought treatment interactions were observed on photosynthesis or plant biomass. In conclusion, a 30% increase in UV-B had no effects on photosynthetic performance or productivity in well-watered or droughted pea plants in the field. (author)

  12. A SIMPLE EVOLUTIONAL MODEL OF THE UV HABITABLE ZONE AND THE POSSIBILITY OF PERSISTENT LIFE EXISTENCE: THE EFFECTS OF MASS AND METALLICITY

    Energy Technology Data Exchange (ETDEWEB)

    Oishi, Midori; Kamaya, Hideyuki [Department of Earth and Ocean Sciences, School of Applied Sciences, National Defense Academy of Japan Yokosuka, 239-8686 (Japan)

    2016-12-20

    In addition to the habitable zone (HZ), the UV habitable zone (UV-HZ) is important when considering the existence of persistent life in the universe. The UV-HZ is defined as the area where the UV radiation field from a host star is moderate for persistent life existence. This is because UV is necessary for the synthesis of biochemical compounds. The UV-HZ must overlap the HZ when life appears and evolves. In this paper, following our previous study of the HZ, we examine the UV-HZ in cases with a stellar mass range from 0.08 to 4.00 M {sub ☉} with various metallicities during the main sequence phase. This mass range was chosen because we are interested in an environment similar to that of Earth. The effect of metallicity is reflected in the spectrum of the host stars, and we reexamine it in the context of the UV-HZ. The present work shows the effect of metallicity when that in the UV-HZ is less than that in the HZ. Furthermore, we find that the chance of persistent life existence declines as the metallicity decreases, as long as the UV radiation is not protected and/or boosted by any mechanisms. This is because the overlapped region of a persistent HZ and UV-HZ decreases. We find that the most appropriate stellar mass for the persistence of life existence is from 1.0 to 1.5 M {sub ☉} with metallicity Z  = 0.02, and only about 1.2 M {sub ☉} with Z  = 0.002. When Z  = 0.0002, the chance of persistent life existence is very low, assuming that the ocean does not protect the life from UV radiation.

  13. Monitoring and control of UV and UV-TiO2 disinfections for municipal wastewater reclamation using artificial neural networks

    International Nuclear Information System (INIS)

    Lin, Chuang-Hung; Yu, Ruey-Fang; Cheng, Wen-Po; Liu, Chun-Ru

    2012-01-01

    Highlights: ► ANN models can effectively control both UV and UV-TiO 2 disinfections for wastewater reuse. ► Comparing to UV disinfection, UV-TiO 2 disinfection can save 13.2–15.7% of UV dosage and capacity. ► SS decreases disinfection efficiency when UV doses were 2 . - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO 2 can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO 2 disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO 2 disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO 2 disinfections. A novel ANN control strategy is applied to control UV and UV-TiO 2 disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO 2 disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO 2 disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2–15.7%.

  14. Deep-UV Emitters and Detectors Based on Lattice-Matched Cubic Oxide Semiconductors (4.2 Optoelectronics)

    Science.gov (United States)

    2015-05-14

    calculated   by   dividing   photo-­‐‑ generated  current  by  the  optical  power  spectrum  of  the   lamp .    A   UV ...the optimized parameters for growth. Efforts led to significant increases in solar?blind detector responsivity (up to 0.1 A/W) with sub-­ nanoamp...Aug-2014 Approved for Public Release; Distribution Unlimited Final Report: Deep- UV Emitters and Detectors Based on Lattice- Matched Cubic Oxide

  15. Luminescence- and nanoparticle-mediated increase of light absorption by photoreceptor cells: Converting UV light to visible light

    OpenAIRE

    Li, Lei; Sahi, Sunil K.; Peng, Mingying; Lee, Eric B.; Ma, Lun; Wojtowicz, Jennifer L.; Malin, John H.; Chen, Wei

    2016-01-01

    We developed new optic devices ? singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light ? for improvement of visual system functions. Tb3+ or Eu3+ singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542?nm or 613?nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals,...

  16. Deep UV to NIR Space Telescopes and Exoplanet Coronagraphs: A Trade Study on Throughput, Polarization, Mirror Coating Options and Requirements

    Science.gov (United States)

    Balasubramanian, Kunjithapatham; Shaklan, Stuart; Give'on, Amir; Cady, Eric; Marchen, Luis

    2011-01-01

    The NASA Exoplanet program and the Cosmic Origins program are exploring technical options to combine the visible to NIR performance requirements of a space coronagraph with the general astrophysics requirements of a space telescope covering the deep UV spectrum. Are there compatible options in terms of mirror coatings and telescope architecture to satisfy both goals? In this paper, we address some of the main concerns, particularly relating to polarization in the visible and throughput in the UV. Telescope architectures employing different coating options compatible with current technology are considered in this trade study.

  17. Very high resolution UV and x-ray spectroscopy and imagery of solar active regions. Final report

    International Nuclear Information System (INIS)

    Bruner, M.; Brown, W.A.; Haisch, B.M.

    1987-01-01

    A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft x-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the x-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical x-ray observations using this new technique

  18. The UV Sensor Onboard the Mars Science Laboratory Mission: Correction and Generation of UV Fluxes

    Science.gov (United States)

    Vicente-Retortillo, Á.; Martinez, G.; Renno, N. O.; Lemmon, M. T.; Gomez-Elvira, J.

    2017-12-01

    The Rover Environmental Monitoring Station UV sensor (UVS) onboard the Mars Science Laboratory mission has completed more than 1750 sols of measurements, providing an unprecedented coverage ranging from diurnal to interannual times scales [1,2]. The UVS is comprised of six photodiodes to measure the UV flux in the ranges 200-380, 320-380, 280-320, 200-280, 230-290 and 300-350 nm [3]. UV fluxes in units of W/m2 can be found in the NASA Planetary Data System (PDS). However, dust deposition on the UVS and a non-physical discontinuity in the calibration functions when the solar zenith angle is above 30º cause errors in these fluxes that increase with time. We have developed a technique to correct UV fluxes from the effects of dust degradation and inconsistencies in the angular response of the UVS. The photodiode output currents (available in the PDS as lower-level TELRDR products), ancillary data records (available in the PDS as ADR products) and dust opacity values derived from Mastcam observations are used for performing the corrections. The corrections have been applied to the UVA band (320-380 nm) for the first 1000 sols of the mission, providing excellent results [4]. We plan to correct the UV fluxes on each of the six UVS bands and to make these results available in the PDS. Data products generated by this study will allow comparisons of the UV radiation environment at Gale crater with that at the locations of the future missions ExoMars 2020 and Mars 2020, as well as the assessment of the potential survivability of biological contaminants brought to Mars from Earth. References: [1] Smith, M. D., et al. (2016), Aerosol optical depth as observed by the Mars Science Laboratory REMS UV photodiodes, Icarus, 280, 234-248. [2] Vicente-Retortillo, Á., et al. (2017), Determination of dust aerosol particle size at Gale Crater using REMS UVS and Mastcam measurements, Geophys. Res. Lett., 44, 3502-3508. [3] Gómez-Elvira, J., et al. (2012), REMS: The environmental sensor

  19. Tolerance of the eriophyid mite Aceria salsolae to UV-A light and implications for biological control of Russian thistle.

    Science.gov (United States)

    Moran, Patrick J; Wibawa, M Irene; Smith, Lincoln

    2017-12-01

    Aceria salsolae (Acari: Eriophyidae) is being evaluated as a candidate biological control agent of Russian thistle (Salsola tragus, Chenopodiaceae), a major invasive weed of rangelands and dryland crops in the western USA. Prior laboratory host range testing under artificial lighting indicated reproduction on non-native Bassia hyssopifolia and on a native plant, Suaeda calceoliformis. However, in field tests in the native range, mite populations released on these 'nontarget' plants remained low. We hypothesized that UV-A light, which can affect behavior of tetranychid mites, would affect populations of the eriophyid A. salsolae differently on the target and nontarget plant species, decreasing the mite's realized host range. Plants were infested with A. salsolae under lamps that emitted UV-A, along with broad-spectrum lighting, and the size of mite populations and plant growth was compared to infested plants exposed only to broad-spectrum light. Russian thistle supported 3- to 55-fold larger mite populations than nontarget plants regardless of UV-A treatment. UV-A exposure did not affect mite populations on Russian thistle or S. calceoliformis, whereas it increased populations 7-fold on B. hyssopifolia. Main stems on nontarget plants grew 2- to 6-fold faster than did Russian thistle under either light treatment. The two nontarget plants attained greater volume under the control light regime than UV-A, but Russian thistle was unaffected. Although Russian thistle was always the superior host, addition of UV-A light to the artificial lighting regime did not reduce the ability of A. salsolae to reproduce on the two nontarget species, suggesting that UV-B or other environmental factors may be more important in limiting mite populations in the field.

  20. Mechanisms of uv mutagenesis in yeast

    International Nuclear Information System (INIS)

    Lawrence, C.W.; Christensen, R.; Schwartz, A.

    1982-01-01

    The uv mutagenesis in yeast depends on the function of the RAD6 locus, a gene that is also responsible for a substantial fraction of wild-type resistance, suggesting that this eukaryote may possess a misrepair mechanism analogous to that proposed for Escherichia coli. The molecular mechanism responsible for RAD6 repair or recovery is not yet known, but it is different from either excision or recombination-dependent repair, processes carried out by the other two main repair pathways in yeast. RAD6-dependent mutagenesis has been found to have the following characteristics. It is associated at best with only a small fraction of RAD6-dependent repair, the majority of the sensitivity of rad6 mutants being due to their lack of nonmutagenic repair. SRS2 metabolic suppressors restore a substantial fraction of uv resistance to rad6 mutants but do not restore their uv mutability. Strains containing mutations at loci (rev, umr) that are probably more directly involved in mutagenesis are only mildly sensitive, and there is a poor correlation between their sensitivity and mutational deficiency. The uv mutagenesis appears to require a large number of gene functions, perhaps ten or more. Where examined in detail, these genes have been found to be concerned in the production of only a specific range of mutational events, not all of them. Mating experiments have shown that a substantial fraction, probably 40% or more, of uv-induced mutations are untargeted, that is, occur in lesion-free regions of DNA. The uv irradiation, therefore, produces a general reduction in the normally high fidelity with which DNA is replicated on undamaged templates. It does not appear to be necessary for the causal lesion to be present in the same chromosome as the mutation it induces. The reduction in fidelity may be the consequence of the production of a diffusible factor in uv-irradiated cells, but definite evidence supporting this proposal has not yet been obtained

  1. Adaptive spectrum decision framework for heterogeneous dynamic spectrum access networks

    CSIR Research Space (South Africa)

    Masonta, M

    2015-09-01

    Full Text Available Spectrum decision is the ability of a cognitive radio (CR) system to select the best available spectrum band to satisfy dynamic spectrum access network (DSAN) users¿ quality of service (QoS) requirements without causing harmful interference...

  2. Broadening the radiography spectrum

    International Nuclear Information System (INIS)

    Waswa, L.; Mutwasi, O.; Kioko, J.

    2006-05-01

    The text discuses the mammography in breast screening and evaluation of breast cancer; Small parts ultrasounds at plaza imaging solutions; role of a Radiographer in mammography-new perspective; Medical imaging education in africa; Caring for the paediatric patient as to broaden radiotherapy spectrum; Problems and challenges in care for children undergoing radiotherapy; Paediatric radiotherapy, management and side effects; The principles of pattern recognition of skeletal structures; the place of distance learning education in broadening the radiography spectrum; the curriculum and budgeting image; sonographer's guide; Computed radiography- X-Ray with vision; digital Radiography in Kenya today; Particle Therapy at Ithemba Labs; The role of lung perfusion and ventilation study in the evaluation of the pulmonary embolism and lastly, an overview of Head and neck treatment at Kenyatta National hospital radiotherapy

  3. Raman spectrum of asphaltene

    KAUST Repository

    Abdallah, Wael A.; Yang, Yang

    2012-01-01

    Asphaltenes extracted from seven different crude oils representing different geological formations from around the globe were analyzed using the Raman spectroscopic technique. Each spectrum is fitted with four main peaks using the Gaussian function. On the basis of D1 and G bands of the Raman spectrum, asphaltene indicated an ordered structure with the presence of boundary defected edges. The average aromatic sheet size of the asphaltene molecules is estimated within the range of 1.52-1.88 nm, which represents approximately seven to eight aromatic fused rings. This estimation is based on the integrated intensity of D1 and G bands, as proposed by Tunistra and Koenig. The results here are in perfect agreement with so many other used techniques and indicate the potential applicability of Raman measurements to determine the average aromatic ring size and its boundary. © 2012 American Chemical Society.

  4. Raman spectrum of asphaltene

    KAUST Repository

    Abdallah, Wael A.

    2012-11-05

    Asphaltenes extracted from seven different crude oils representing different geological formations from around the globe were analyzed using the Raman spectroscopic technique. Each spectrum is fitted with four main peaks using the Gaussian function. On the basis of D1 and G bands of the Raman spectrum, asphaltene indicated an ordered structure with the presence of boundary defected edges. The average aromatic sheet size of the asphaltene molecules is estimated within the range of 1.52-1.88 nm, which represents approximately seven to eight aromatic fused rings. This estimation is based on the integrated intensity of D1 and G bands, as proposed by Tunistra and Koenig. The results here are in perfect agreement with so many other used techniques and indicate the potential applicability of Raman measurements to determine the average aromatic ring size and its boundary. © 2012 American Chemical Society.

  5. Spread spectrum image steganography.

    Science.gov (United States)

    Marvel, L M; Boncelet, C R; Retter, C T

    1999-01-01

    In this paper, we present a new method of digital steganography, entitled spread spectrum image steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, error-control coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embedded control, and revision tracking.

  6. Effects of UV-B radiation on the isoflavone accumulation and physiological-biochemical changes of soybean during germination: Physiological-biochemical change of germinated soybean induced by UV-B.

    Science.gov (United States)

    Ma, Meng; Wang, Pei; Yang, Runqiang; Gu, Zhenxin

    2018-06-01

    In this study, the effects of UV-B radiation on the isoflavones accumulation, physiological and nutritional quality, water status, and characteristics of proteins in germinated soybeans were investigated. The results showed that isoflavones content in soybeans increased with appropriate intensity and time of UV-B radiation and decreased with excessive treatment. Fresh weight, length, free amino acids, reducing sugar contents and bulk water (T 23 ) in germinated soybeans decreased with increasing radiation time, indicating that UV-B inhibited the growth and nutrients metabolism of soybean during germination. Cell damage was detected in germinated soybeans with excessive UV-B radiation, as shown by the black spots in cotyledons and the increased intercellular water determined by LF-NMR. Germination resulted in an increase in random coil structures, while UV-B radiation induced no obvious changes in FT-IR spectrum and protein conformation of soybeans. Both UV-B radiation and germination caused the increase in soluble proteins, especially in 1.0-75.0 kDa fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Plant Responses to Increased UV-B Radiation: A Research Project

    Science.gov (United States)

    DAntoni, H. L.; Skiles, J. W.; Armstrong, R.; Coughlan, J.; Daleo, G.; Mayoral, A.; Lawless, James G. (Technical Monitor)

    1994-01-01

    because there is anecdotal evidence of plant damage on the saguaros that has been linked to increased UV radiation, and (3) the forests of Nothofagus spp. and the steppe of Patagonia where the risk of plant damage at 35S is 5% and increases to as much as 15% at 55S due to increased UV-B radiation. Measurements of UV-B radiation impinging on the surface at 55S largely exceed the predicted UV-B radiation values at 50 latitude and 0% ozone depletion. Preliminary HPLC analyses of UV-B absorbing compounds in Nothofagus antartica, N. pumilio, N. betuloides and Rumex sp. in natural conditions show species-specific patterns. The spectrum of N. antartica grown at 38S differs significantly from that of N. antartica in natural conditions in Ushuaia (55S). These results suggest that the selected main area (Patagonia) is appropriate for assessing the problem and its magnitude and that Nothofagus is appropriate for our study.

  8. Natural organic UV-absorbent coatings based on cellulose and lignin: designed effects on spectroscopic properties.

    Science.gov (United States)

    Hambardzumyan, Arayik; Foulon, Laurence; Chabbert, Brigitte; Aguié-Béghin, Véronique

    2012-12-10

    Novel nanocomposite coatings composed of cellulose nanocrystals (CNCs) and lignin (either synthetic or fractionated from spruce and corn stalks) were prepared without chemical modification or functionalization (via covalent attachment) of one of the two biopolymers. The spectroscopic properties of these coatings were investigated by UV-visible spectrophotometry and spectroscopic ellipsometry. When using the appropriate weight ratio of CNC/lignin (R), these nanocomposite systems exhibited high-performance optical properties, high transmittance in the visible spectrum, and high blocking in the UV spectrum. Atomic force microscopy analysis demonstrated that these coatings were smooth and homogeneous, with visible dispersed lignin nodules in a cellulosic matrix. It was also demonstrated that the introduction of nanoparticles into the medium increases the weight ratio and the CNC-specific surface area, which allows better dispersion of the lignin molecules throughout the solid film. Consequently, the larger molecular expansion of these aromatic polymers on the surface of the cellulosic nanoparticles dislocates the π-π aromatic aggregates, which increases the extinction coefficient and decreases the transmittance in the UV region. These nanocomposite coatings were optically transparent at visible wavelengths.

  9. The New World Observer: Scientific rationale for detecting biomarkers between the UV and near infrared

    Science.gov (United States)

    Seager, S.; Wilkinson, E.; Cash, W.

    2003-12-01

    The New World Observer(NWO) is a distributed instrument concept designed for UV/visible wavelength spectroscopy of extrasolar planets and was submitted in response to the NASA "Vision Mission" announcement of opportunity. NWO is essentially a pinhole camera where the "pinhole" and the "detector" are separate, formation flying spacecraft separated by ˜180,000 km. The size of the "pinhole" and distance from the "detector" spacecraft are optimized for isolating the image of an Earth-like planet from it's parent star at the focal plane and minimizing the time necessary to acquire a low-resolution spectrum of the planet. We present the scientific rationale behind observing in the UV/visible/near-IR portion of the electromagnetic spectrum and simulations of potential spectra. We discuss the biomarkers that exist from UV wavelengths through 2 microns, including, but not limited to, water, oxygen, ozone, nitrous oxide, and methane, and possible interpretations that can be derived from detections of these biomarkers. Also discussed are the effects of vegetation, weather, and planetary rotation. Simulations of observed spectra assume different instrument configurations and explore the sensitivity of NWO to a variety of biomarkers. Ultimately, the simulations demonstrate the power of the NWO concept for acquiring high quality spectra of Earth-like planets out to tens of parsecs.

  10. Vibrational and UV spectroscopic studies of 2-coumaranone by experimental and density functional theory calculations

    Science.gov (United States)

    Priya, Y. Sushma; Rao, K. Ramachandra; Chalapathi, P. V.; Satyavani, M.; Veeraiah, A.

    2017-09-01

    The vibrational and electronic properties of 2-coumaranone have been reported in the ground state using experimental techniques (FT-IR, FT-Raman, UV spectra and fluorescence microscopic imaging) and density functional theory (DFT) employing B3LYP correlation with the 6-31G(d, p) basis set. The theoretically reported optimized parameters, vibrational frequencies etc., were compared with the experimental values, which yielded good concurrence between the experimental and calculated values. The assignments of the vibrational spectra were done with the help of normal co-ordinate analysis (NCA) following the Scaled Quantum Mechanical Force Field(SQMFF) methodology. The whole assignments of fundamental modes were based on the potential energy distribution (PED) matrix. The electric dipole moment and the first order hyperpolarizability of the 2-coumaranone have been computed using quantum mechanical calculations. NBO and HOMO, LUMO analyses have been carried out. UV spectrum of 2-coumaranone was recorded in the region 100-300 nm and compared with the theoretical UV spectrum using TD-DFT and SAC-CI methods by which a good agreement is observed. Fluorescence microscopic imaging study reflects that the compound fluoresces in the green-yellow region.

  11. Use of satellite erythemal UV products in analysing the global UV changes

    Directory of Open Access Journals (Sweden)

    I. Ialongo

    2011-09-01

    Full Text Available Long term changes in solar UV radiation affect global bio-geochemistry and climate. The satellite-based dataset of TOMS (Total Ozone Monitoring System and OMI (Ozone Monitoring Instrument of erythemal UV product was applied for the first time to estimate the long-term ultraviolet (UV changes at the global scale. The analysis of the uncertainty related to the different input information is presented. OMI and GOME-2 (Global Ozone Monitoring Experiment-2 products were compared in order to analyse the differences in the global UV distribution and their effect on the linear trend estimation.

    The results showed that the differences in the inputs (mainly surface albedo and aerosol information used in the retrieval, affect significantly the UV change calculation, pointing out the importance of using a consistent dataset when calculating long term UV changes. The areas where these differences played a major role were identified using global maps of monthly UV changes. Despite the uncertainties, significant positive UV changes (ranging from 0 to about 5 %/decade were observed, with higher values in the Southern Hemisphere at mid-latitudes during spring-summer, where the largest ozone decrease was observed.

  12. The World Space Observatory Ultraviolet (WSO-UV), as a bridge to future UV astronomy

    Science.gov (United States)

    Shustov, B.; Gómez de Castro, A. I.; Sachkov, M.; Vallejo, J. C.; Marcos-Arenal, P.; Kanev, E.; Savanov, I.; Shugarov, A.; Sichevskii, S.

    2018-04-01

    Ultraviolet (UV) astronomy is a vital branch of space astronomy. Many dozens of short-term UV-experiments in space, as well as long-term observatories, have brought a very important knowledge on the physics and chemistry of the Universe during the last decades. Unfortunately, no large UV-observatories are planned to be launched by most of space agencies in the coming 10-15 years. Conversely, the large UVOIR observatories of the future will appear not earlier than in 2030s. This paper briefly describes the projects that have been proposed by various groups. We conclude that the World Space Observatory-Ultraviolet (WSO-UV) will be the only 2-m class UV telescope with capabilities similar to those of the HST for the next decade. The WSO-UV has been described in detail in previous publications, and this paper updates the main characteristics of its instruments and the current state of the whole project. It also addresses the major science topics that have been included in the core program of the WSO-UV, making this core program very relevant to the current state of the UV-astronomy. Finally, we also present here the ground segment architecture that will implement this program.

  13. Wastewater disinfection with peracetic acid and UV

    International Nuclear Information System (INIS)

    Caretti, C.; Lubello, C.

    2001-01-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm - 2 is enough to meet the Italian limit [it

  14. UV Catalysis, Cyanotype Photography, and Sunscreens

    Science.gov (United States)

    Lawrence, Glen D.; Fishelson, Stuart

    1999-09-01

    This laboratory experiment is intended for a chemistry course for non-science majors. The experiment utilizes one of the earliest photographic processes, the cyanotype process, to demonstrate UV catalysis of chemical reactions. In addition to making photographic prints from negatives, the process can be used to test the effectiveness of sunscreens and the relative efficacy of the SPF (sun protection factor) rating of sunscreens. This is an inexpensive process, requiring solutions of ammonium ferric citrate and potassium ferricyanide, with options to use hydrogen peroxide and ammonium hydroxide solutions. Students can prepare their own UV-sensitized paper with the indicated chemicals and watch the photographic image appear as it is exposed to sunlight or fluorescent UV lamps in a light box designed for use in this experiment. The laboratory experiment should stimulate discussion of UV catalysis, photographic processes and photochemistry, sunscreens, and UV damage to biological organisms. The chemicals used are relatively nontoxic, and the procedure is simple enough to be used by groups of diverse ages and abilities.

  15. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation on growth of cucumber

    International Nuclear Information System (INIS)

    Krizek, D.T.; Mirecki, R.M.; Britz, S.J.

    1997-01-01

    The influence of solar UV-A and UV-B radiation at Beltsville, Maryland, on growth and flavonoid content in four cultivars of Cucumis sativus L. (Ashley, Poinsett, Marketmore, and Salad Bush cucumber) was examined during the summers of 1994 and 1995. Plants were grown from seed in UV exclusion chambers consisting of UV-transmitting Plexiglas, lined with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or cellulose acetate to transmit UV-A and UV-B. Despite previously determined differences in sensitivity to supplemental UV-B radiation, all four cultivars responded similarly to UV-B exclusion treatment. After 19–21 days, the four cultivars grown in the absence of solar UV-B (polyester) had an average of 34, 55, and 40% greater biomass of leaves, stems, and roots, respectively, 27% greater stem height, and 35% greater leaf area than those grown under ambient UV-B (cellulose acetate). Plants protected from UV-A radiation as well (Llumar) showed an additional 14 and 22% average increase, respectively, in biomass of leaves and stems, and a 22 and 19% average increase, respectively, in stem elongation and leaf area over those grown under polyester. These findings demonstrate the extreme sensitivity of cucumber not only to present levels of UV-B but also to UV-A and suggest that even small changes in ozone depletion may have important biological consequences for certain plant species. (author)

  16. Numerical and experimental investigation of UV disinfection for water treatment

    International Nuclear Information System (INIS)

    Li, H.Y.; Osman, H.; Kang, C.W.; Ba, T.

    2017-01-01

    Highlights: • UV irradiation for water treatment is numerically and experimentally investigated. • Fluence rate E increases exponentially with the increase of UVT. • UV dose distribution moves to a high range with increase of UVT and lamp power. • A linear relationship is observed between fluence rate E and average UV dose D_a_v_e. • D_a_v_e decreases with the increase of UVT and fluid flow rate. - Abstract: Disinfection by ultraviolet (UV) for water treatment in a UV reactor is numerically and experimentally investigated in this paper. The flow of water, UV radiation transportation as well as microorganism particle trajectories in the UV reactor is simulated. The effects of different parameters including UV transmittance (UVT), lamp power and water flow rate on the UV dose distribution and average UV dose are studied. The UV reactor performance in terms of average UV dose under these parameters is analysed. Comparisons are made between experiments and simulations on the average UV dose and reasonable agreement is achieved. The results show that the fluence rate increases exponentially with the increase of UVT. The UV dose distribution profiles moves to a high range of UV dose with the increase of UVT and lamp power. The increase of water flow rate reduces the average exposure time of microorganism particles to the UV light, resulting in the shifting of UV dose distribution to a low range of UV dose. A linear relationship is observed between fluence rate and the average UV dose. The average UV dose increases with the increase of lamp power while it decreases with the increase of UVT and water flow rate.

  17. Tekstilde Uv Absorban Madde Uygulamaları The Applications of UV Absorber on Textiles

    OpenAIRE

    MERDAN, Nigar; ACAR, Kamil

    2009-01-01

    Tekstiller UV radyasyonuna karşı koruma sağlarken, bu aşamada radyasyonun dozu da önem taşımaktadır. Bu nedenle tekstil materyallerine UV absorban maddeler, liflerin üretimi esnasında ya da bitim işlemlerinde uygulanmaktadır. UV absorban maddelerin kullanılmasıyla, tekstil ürünlerinde UV ışınlarının geçirgenliğinin yoğunluk derecesi azaltılır. UV absorbanları, materyale gelen ışık tarafından oluşan olumsuz etkileri engeller

  18. Patterning of nanoparticulate transparent conductive ITO films using UV light irradiation and UV laser beam writing

    International Nuclear Information System (INIS)

    Solieman, A.; Moharram, A.H.; Aegerter, M.A.

    2010-01-01

    Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency (∼85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ□.

  19. Hybrid spread spectrum radio system

    Science.gov (United States)

    Smith, Stephen F [London, TN; Dress, William B [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  20. Effect of far-UV and near-UV radiation on the cell surface charge of the protozoan Tritrichomonas foetus

    Energy Technology Data Exchange (ETDEWEB)

    Silva Filho, F C; Elias, C A; Souza, W de

    1986-05-01

    Cell electrophoresis was used to detect the effect of far-UV or near-UV radiation on the cell surface charge of the pathogenic protozoan Tritrichomonas foetus. Either far-UV or near-UV radiation interfered with the surface charge of T. foetus at fluences which inhibited cell growth by 50%. Both UV-radiations induced a significant decrease on surface charge of T. foetus, as evaluated by measurement of its electrophoretic mobility (EPM). Determinations of EPM of protozoa in solution of low ionic strength indicated that the decrease in the EPM induced by far-UV is much less pronounced that that observed for near-UV or control cells.

  1. UV SEDs of early-type cluster galaxies: a new look at the UV upturn

    Science.gov (United States)

    Ali, S. S.; Bremer, M. N.; Phillipps, S.; De Propris, R.

    2018-05-01

    Using GALEX, Ultraviolet Optical Telescope (UVOT), and optical photometry, we explore the prevalence and strength of the Ultraviolet (UV) upturn in the spectra of quiescent early-type galaxies in several nearby clusters. Even for galaxies with completely passive optical colours, there is a large spread in vacuum UV colour consistent with almost all having some UV upturn component. Combining GALEX and UVOT data below 3000 Å, we generate for the first time comparatively detailed UV spectral energy distributions for Coma cluster galaxies. Fitting the UV upturn component with a blackbody, 26 of these show a range of characteristic temperatures (10 000-21 000K) for the UV upturn population. Assuming a single temperature to explain GALEX-optical colours could underestimate the fraction of galaxies with UV upturns and mis-classify some as systems with residual star formation. The UV upturn phenomenon is not an exclusive feature found only in giant galaxies; we identify galaxies with similar (or even bluer) FUV - V colours to the giants with upturns over a range of fainter luminosities. The temperature and strength of the UV upturn are correlated with galaxy mass. Under the plausible hypothesis that the sources of the UV upturn are blue horizontal branch stars, the most likely mechanism for this is the presence of a substantial (between 4 per cent and 20 per cent) Helium-rich (Y > 0.3) population of stars in these galaxies, potentially formed at z ˜ 4 and certainly at z > 2; this plausibly sets a lower limit of {˜ } {0.3- 0.8} × 10^{10} M⊙ to the in situ stellar mass of ˜L* galaxies at this redshift.

  2. Fast radio burst search: cross spectrum vs. auto spectrum method

    Science.gov (United States)

    Liu, Lei; Zheng, Weimin; Yan, Zhen; Zhang, Juan

    2018-06-01

    The search for fast radio bursts (FRBs) is a hot topic in current radio astronomy studies. In this work, we carry out a single pulse search with a very long baseline interferometry (VLBI) pulsar observation data set using both auto spectrum and cross spectrum search methods. The cross spectrum method, first proposed in Liu et al., maximizes the signal power by fully utilizing the fringe phase information of the baseline cross spectrum. The auto spectrum search method is based on the popular pulsar software package PRESTO, which extracts single pulses from the auto spectrum of each station. According to our comparison, the cross spectrum method is able to enhance the signal power and therefore extract single pulses from data contaminated by high levels of radio frequency interference (RFI), which makes it possible to carry out a search for FRBs in regular VLBI observations when RFI is present.

  3. EB/UV curing market in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Khairul Zaman; Nik Salleh, Nik Ghazali; Mahmood, Mohd Hilmi [Malaysian Inst. for Nuclear Technology Res. (MINT), Bangi (Malaysia)

    1999-07-01

    Radiation curing of coatings of wood based products is expanding and being used for curing of coatings of table tops, parquet, wood panel, furniture, curtain railing, etc. UV curing of over print varnish is still the main application of UV curing in printing industry. However, curing ofprinting ink has also been extended in the printing of CD and VCD in addition to other printing such as paper, magazine, label on bottles, metal-can, etc. In the electronic industry, the manufacturer of printed circuit board is still the main consumer of UV curable resins. On the other hand, low energy electron beam machine is used mainly for cross-linking of heat shrink films.

  4. EB/UV curing market in Malaysia

    International Nuclear Information System (INIS)

    Khairul Zaman Dahlan; Nik Ghazali Nik Salleh; Mohd Hilmi Mahmood

    1999-01-01

    Radiation curing of coatings of wood based products is expanding and being used for curing of coatings of table tops, parquet, wood panel, furniture, curtain railing, etc. UV curing of over print varnish is still the main application of UV curing in printing industry. However, curing of printing ink has also been extended in the printing of CD and VCD in addition to other printing such as paper, magazine, label on bottles, metal-can, etc. In the electronic industry, the manufacturer of printed circuit board is still the main consumer of UV curable resins. On the other hand, low energy electron beam machine is used mainly for cross-linking of heat shrink films

  5. Putative Enzymes of UV Photoproduct Repair

    Directory of Open Access Journals (Sweden)

    Cynthia J. Sakofsky

    2011-01-01

    Full Text Available In order to determine the biological relevance of two S. acidocaldarius proteins to the repair of UV photoproducts, the corresponding genes (Saci_1227 and Saci_1096 were disrupted, and the phenotypes of the resulting mutants were examined by various genetic assays. The disruption used integration by homologous recombination of a functional but heterologous pyrE gene, promoted by short sequences attached to both ends via PCR. The phenotypic analyses of the disruptants confirmed that ORF Saci_1227 encodes a DNA photolyase which functions in vivo, but they could not implicate ORF Saci_1096 in repair of UV- or other externally induced DNA damage despite its similarity to genes encoding UV damage endonucleases. The success of the gene-disruption strategy, which used 5′ extensions of PCR primers to target cassette integration, suggests potential advantages for routine construction of Sulfolobus strains.

  6. UV-induced structural changes in chromatin

    International Nuclear Information System (INIS)

    Lang, H.; Zimmer, C.; Vengerov, Yu.Yu.

    1985-01-01

    UV-induced structural alterations of chromatin were studied by means of CD, electron microscopic, and gel electrophoretic measurements. The results indicate that chromatin undergoes serious structural changes after irradiation even at very low fluences. In the low fluence range the structural transitions from the higher ordered chromatin structure to the unfolded state occur without detectable changes in the content of histone H1 and of the core histones. Histone H1 disappears only at fluences above 10 kJ/m 2 . Furthermore, DNA in chromatin is much more sensitive against UV-irradiation and shows a higher degree of strand scission relative to free DNA. While fragmentation in free DNA occurs at fluences above 15 kJ/m 2 , it occurs even at 5.5 kJ/m 2 in the case of chromatin. The biological meaning of the observed UV-induced structural alterations of chromatin is discussed. (author)

  7. UV-LIGA: From Development to Commercialization

    Directory of Open Access Journals (Sweden)

    Grégoire Genolet

    2014-07-01

    Full Text Available A major breakthrough in UV-LIGA (Lithographie, Galvanoformung and Abformung started with the use of epoxy-based EPON® SU-8 photoresist in the mid-1990s. Using this photoresist has enabled the fabrication of tall and high aspect ratio structures without the use of a very expensive synchrotron source needed to expose the photoresist layer in X-ray LIGA. SU-8 photoresist appeared to be well-suited for LIGA templates, but also as a permanent material. Based on UV-LIGA and SU-8, Mimotec SA has developed processes to manufacture mold inserts and metallic components for various market fields. From one to three-level parts, from Ni to other materials, from simple to complicated parts with integrated functionalities, UV-LIGA has established itself as a manufacturing technology of importance for prototyping, as well as for mass-fabrication. This paper reviews some of the developments that led to commercial success in this field.

  8. Mechanical and thermal properties of UV curable polyurethane acrylate composite coatings

    International Nuclear Information System (INIS)

    Mohd Sofian Alias; Nik Ghazali Nik Salleh; Mohd Hamzah Harun; Mohd Yusof Hamzah; Rosley Che Ismail

    2012-01-01

    UV curable coating formulation comprises urethane acrylate resin and nano silica as filter were synthesized to develop UV curable inorganic hybrid composite (PUA). The surface of the nano silica was chemically modified to improve its chemical interaction within the urethane acrylate matrix. The modification had been undertaken by applying vinyltrymetoxysilane (VTMOS) that acted as a coupling agent to produce organophilic silica shell (SIMA). The shell is linked to the silica via reaction with the surface silanol group of the silica. The disappearance of methoxy groups in VTMOS was demonstrated by FTIR spectrum. The percentage of silica particles in UV curable hybrid formulation were varied on 5 %, 10 %, 15 %, 20 % and 25 wt % respectively. In this work, the formulation was applied on medium density fiber board (MDF) substrate and subsequent has been irradiated under UV light. Then, the coated MDF were characterized by several testing equipment (TGA, DSC, scratch tester, instron, SEM). From the result, we found that the addition of silica nanoparticles exhibit significant improvement in coating film properties as compared to film without silica nanoparticle includes significant improvement in its modulus and scratch resistance. This make them as promising coating candidate for MDF product. On the other hand, we also found that an increase of silica particle up to 25 wt %, the viscosity has increased rapidly indicates that it is not suitable for acrylate coating formulation due to disappearance of desired effect known as thixotropy. (Author)

  9. On gauge invariant cosmological perturbations in UV-modified Hořava gravity

    Science.gov (United States)

    Shin, Sunyoung; Park, Mu-In

    2017-12-01

    We consider gauge invariant cosmological perturbations in UV-modified, z = 3 (non-projectable) Hořava gravity with one scalar matter field, which has been proposed as a renormalizable gravity theory without the ghost problem in four dimensions. In order to exhibit its dynamical degrees of freedom, we consider the Hamiltonian reduction method and find that, by solving all the constraint equations, the degrees of freedom are the same as those of Einstein gravity: one scalar and two tensor (graviton) modes when a scalar matter field presents. However, we confirm that there is no extra graviton modes and general relativity is recovered in IR, which achieves the consistency of the model. From the UV-modification terms which break the detailed balance condition in UV, we obtain scale-invariant power spectrums for non-inflationary backgrounds, like the power-law expansions, without knowing the details of early expansion history of Universe. This could provide a new framework for the Big Bang cosmology. Moreover, we find that tensor and scalar fluctuations travel differently in UV, generally. We present also some clarifying remarks about confusing points in the literatures.

  10. Ecological and nonhuman biological effects of solar UV-B radiation

    International Nuclear Information System (INIS)

    Worrest, R.C.

    1984-01-01

    Recent studies regarding the impact of UV-B radiation upon ecological and nonhuman biological systems is the subject of the report. For years scientists and laymen alike have causally noted the impact of solar ultraviolet radiation upon the nonhuman component of the biosphere. Stratospheric ozone functions effectively as an ultraviolet screen by filtering out solar radiation in the 220-320 nm waveband as it penetrates through the atmosphere, thus allowing only small amounts of the longer wavelengths of radiation in the waveband to leak through to the surface of the earth. Although this radiation (UV-B radiation, 290-320 nm) comprises only a small fraction (lesser tha 1%) of the total solar spectrum, it can have a major impact on biological systems due to its actinic nature. Many organic molecules, most notably DNA, absorb UV-B radiation which can initiate photochemical reactions. It is life's ability, or lack thereof, to cope with enhanced levels of solar UV-B radiation that has generated concern over the potential depletion of stratospheric ozone

  11. Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

    Directory of Open Access Journals (Sweden)

    Barthelemy Mathieu

    2014-01-01

    Full Text Available The solar UV (UltraViolet flux, especially the EUV (Extreme UltraViolet and FUV (Far UltraViolet components, is one of the main energetic inputs for planetary upper atmospheres. It drives various processes such as ionization, or dissociation which give rise to upper atmospheric emissions, especially in the UV and visible. These emissions are one of the main ways to investigate the upper atmospheres of planets. However, the uncertainties in the flux measurement or modeling can lead to biased estimates of fundamental atmospheric parameters, such as concentrations or temperatures in the atmospheres. We explore the various problems that can be identified regarding the uncertainties in solar/stellar UV flux by considering three examples. The worst case appears when the solar reflection component is dominant in the recorded spectrum as is seen for outer solar system measurements from HST (Hubble Space Telescope. We also show that the estimation of some particular line parameters (intensity and shape, especially Lyman α, is crucial, and that both total intensity and line profile are useful. In the case of exoplanets, the problem is quite critical since the UV flux of their parent stars is often very poorly known.

  12. Mutation spectrum produced on PBR322 by 8-Methoxypsoralen plus UV-A light

    International Nuclear Information System (INIS)

    Bauluz, C.; Vidania, R.

    1990-01-01

    The mutagenic effect of 8-MOP+UVA (PUVA treatment) on pBR322 has been analysed by determining the frequency of mutation in the tet gene and identifying the type and position of the mutations produced inside a 276 pb-fragment (Bam-H1-SalI) of the same gene. pBR322 DNA was irradiated with UVA light in the presence of increasing concentrations of 8-Methoxypsoralen (8-MOP). The number of psoralen adducts formed in pBR322 upon that treatment ranged from 0 to 10.7 adducts per plasmid molecule. Modified DNA samples were used to transform several strains of E. Coli (differing in their repair capacities), both in constitutive conditions and after sos pre-induction by 254 nm-irradiation of cells. Mutation frequencies in the tet gene showed to increase in the wild type and uvrA strains along with the number of psoralen adducts per plasmid molecule; higher mutation frequencies were found in cells that had been previously irradiated to induce the SOS expression. Mutant plasmids were isolated from ApRTcS colonies and sequenced by the method of Maxam and Gilbert. Mutations appeared to be unique in most of the cases and were always punctual, i.e. affecting only to one base pair. The relative positions of the mutations showed a high frequency of coincidence among the sequenced fragments, indicating the existence of several DNA regions with high probability to mutated ('hot spots'). (author)

  13. Overview of UV and EB curing

    International Nuclear Information System (INIS)

    Garnett, J.L.

    2000-01-01

    Full text: UV and EB are complementary techniques in radiation curing. In the proposed paper, a brief review of both fields will be given. This will include principles of the process, the chemistry of the systems including monomers/oligomers/polymers used, additives required where necessary such as photoinitiators for UV, flow aids, adhesion promoters and the like. The types of equipment used in such processes will also be discussed including low energy electron beam utilisation and excimer curing. The advantages and disadvantages of both techniques will be examined. Mechanistic aspects of both curing systems will be discussed. Applications of the technology including developments in the banknote printing field will be summarised

  14. UV line emission of symbiotic stars

    International Nuclear Information System (INIS)

    Nussbaumer, H.

    1982-01-01

    General characteristics of emission line spectra from symbiotic stars are outlined. Data from some special line ratios in the 1000 A - 3000 A range, and others connecting the visual and the far UV lines are presented, and their application to symbiotic stars is discussed. Integrated fractional abundances for ions easily observed in the far UV are given to facilitate abundance determinations for nebular conditions. It is found that the physical conditions of the regions emitting the emission line spectra differ considerably among different symbiotic stars. (Auth.)

  15. Possible role of protein damages in the origin of UV-induced isochromatid breaks

    International Nuclear Information System (INIS)

    Lebedeva, L.I.; Ostrovskaya, R.M.; Tsimmerman, V.G.

    1978-01-01

    Formation of aberrations was studied in the first and second mitosis following UV irradiation with the aim to elucidate the nature of the sensitive target responsible for aberrations formed during the G 2 period. The primary embryonic fibroblast culture from BALB mice was used; UV irradiation was at 254, 265, 280 and 302 nm and 40 and 80 erg/mm 2 doses. The cycle stages and exact times, when fixation was done, were determined from labelled mitosis curves. The frequency of chromosome aberrations after irradiation of cells at the G 2 stage was approximately the same at the wave lengths of 254, 265 and 280 nm, suggesting that DNA and protein are the targets responsible for aberrations.For chromatid aberrations the efficiency spectrum corresponded to the thymine absorption spectrum. Isochromatid break efficiency spectrum was similar to the protein absorption spectra. Caffeine, when applied during S period of the second mitosis, increased the frequency of chromatid breaks and did not affect other aberrations. It is supposed that the formation of chromatid aberrations and isochromatid breaks is underlied by different mechanisms. Chromatid aberrations are initiated by the formation of DNA-DNA cross linkages resulting from thymine dimers. For isochromatid breaks, the presence of a protein chromophore is important

  16. Experimental Evolution of UV-C Radiation Tolerance: Emergence of Adaptive and Non-Adaptive Traits in Escherichia coli Under Differing Flux Regimes

    Science.gov (United States)

    Moffet, A.; Okansinski, A.; Sloan, C.; Grace, J. M.; Paulino-Lima, I. G.; Gentry, D.; Rothschild, L. J.; Camps, M.

    2014-12-01

    High-energy ultraviolet (UV-C) radiation is a significant challenge to life in environments such as high altitude areas, the early Earth, the Martian surface, and space. As UV-C exposure is both a selection pressure and a mutagen, adaptation dynamics in such environments include a high rate of change in both tolerance-related and non-tolerance-related genes, as well changes in linkages between the resulting traits. Determining the relationship between the intensity and duration of the UV-C exposure, mutation rate, and emergence of UV-C resistance will inform our understanding of both the emergence of radiation-related extremophily in natural environments and the optimal strategies for generating artificial extremophiles. In this study, we iteratively exposed an Escherichia colistrain to UV-C radiation of two different fluxes, 3.3 J/m^2/s for 6 seconds and 0.5 J/m^2/s for 40 seconds, with the same overall fluence of 20 J/m^2. After each iteration, cells from each exposure regime were assayed for increased UV-C tolerance as an adaptive trait. The exposed cells carried a plasmid bearing a TEM beta-lactamase gene, which in the absence of antibiotic treatment is a neutral reporter for mutagenesis. Sequencing of this gene allowed us to determine the baseline mutation frequency for each flux. As an additional readout for adaptation, the presence of extended-spectrum beta-lactamase mutations was tested by plating UV-exposed cultures in cefotaxime plates. We observed an increase of approximately one-million-fold in UV-C tolerance over seven iterations; no significant difference between the two fluxes was found. Future work will focus on identifying the genomic changes responsible for the change in UV-C tolerance; determining the mechanisms of the emerged UV-C tolerance; and performing competition experiments between the iteration strains to quantify fitness tradeoffs resulting from UV-C adaptation.

  17. Imaging with electromagnetic spectrum applications in food and agriculture

    CERN Document Server

    Jayasuriya, Hemantha

    2014-01-01

    This book demonstrates how imaging techniques, applying different frequency bands from the electromagnetic spectrum, are used in scientific research. Illustrated with numerous examples this book is structured according to the different radiation bands: From Gamma-rays over UV and IR to radio frequencies. In order to ensure a clear understanding of the processing methodologies, the text is enriched with descriptions of how digital images are formed, acquired, processed and how to extract information from them. A special emphasis is given to the application of imaging techniques in food and agriculture research.

  18. Spectrum of cosmic fireballs

    Energy Technology Data Exchange (ETDEWEB)

    Cavallo, G [Consiglio Nazionale delle Ricerche, Bologna (Italy). Lab. TESRE; Horstman, H M [Bologna Univ. (Italy). Ist. di Astronomia

    1981-03-01

    A progress report on cosmic fireballs is presented. The main new results are: (a) the phenomenon should be almost universal, and most explosive ..gamma..-ray sources should show the characteristic fireball spectrum; (b) even if the radiation density is insufficient, pair production in electron-proton or electron-electron scattering might start the fireball; (c) some computed fireball spectra are shown. They all have in common a 1/E low-energy behaviour, a 100 keV flattening, and a approx.0.5 MeV cut-off.

  19. Air shower density spectrum

    International Nuclear Information System (INIS)

    Porter, M.R.; Foster, J.M.; Hodson, A.L.; Hazen, W.E.; Hendel, A.Z.; Bull, R.M.

    1982-01-01

    Measurements of the differential local density spectrum have been made using a 1 m 2 discharge chamber mounted in the Leeds discharge chamber array. The results are fitted to a power law of the form h(δ)dδ = kδsup(-ν)dδ, where ν=2.47+-0.04; k=0.21 s - 1 , for 7 m - 2 - 2 ; ν=2.90+-0.22; k=2.18 s - 1 , for δ > 200 m - 2 . Details of the measurement techniques are given with particular reference to the treatment of closely-spaced discharges. A comparison of these results with previous experiments using different techniques is made

  20. Preparation of UV-protective kefiran/nano-ZnO nanocomposites: physical and mechanical properties.

    Science.gov (United States)

    Shahabi-Ghahfarrokhi, Iman; Khodaiyan, Faramarz; Mousavi, Mohammad; Yousefi, Hossein

    2015-01-01

    In this study, we investigated the effect of ZnO nanoparticles (ZN) as a UV-protective agent of kefiran biopolymers. Our results showed that with increasing ZN content, the tensile strength, elongation at break, and tensile energy to break the kefiran film and nanocomposites also increased. Kefiran nanocomposites with a ZN content higher than 2% produced a UV-protective film with good visual properties, low sensibility to water, and low water-vapor permeability. The thermal properties of all specimens, analyzed by DSC, showed that the ZN content had a negative effect on Tg and a positive effect on nanocomposites' melting point. TEM, SEM micrography and XRD spectrum analysis confirmed the hypothesis that ZNs act like a ball bearing, making movement of kefiran chains easier and increasing elongation at break, while simultaneously decreasing the Tg of kefiran nanocomposites. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. A low volume 3D-printed temperature-controllable cuvette for UV visible spectroscopy.

    Science.gov (United States)

    Pisaruka, Jelena; Dymond, Marcus K

    2016-10-01

    We report the fabrication of a 3D-printed water-heated cuvette that fits into a standard UV visible spectrophotometer. Full 3D-printable designs are provided and 3D-printing conditions have been optimised to provide options to print the cuvette in either acrylonitrile butadiene styrene or polylactic acid polymers, extending the range of solvents that are compatible with the design. We demonstrate the efficacy of the cuvette by determining the critical micelle concentration of sodium dodecyl sulphate at 40 °C, the molar extinction coefficients of cobalt nitrate and dsDNA and by reproducing the thermochromic UV visible spectrum of a mixture of cobalt chloride, water and propan-2-ol. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Effects of UV, sunlight and X-ray radiation on quiescent human cells in culture

    International Nuclear Information System (INIS)

    Kantor, G.J.

    1986-01-01

    Nondividing human diploid fibroblasts (HDF) in culture have been used to study the effect on cell lethality of ultraviolet light, natural sunlight and X-rays. A lethal effect is defined as cellular degeneration, loss from the culture and inability to exclude vital strains. Far- and mid-UV have a readily observable lethal effect (cell loss), with DNA and DNA damage as the critical target and critical damage respectively. In part, natural sunlight kills cells by a similar mechanism but has an additional lethal effect at longer exposure times. This additional effect is expressed by the retention of the dead cells in culture, in contrast to the UV-induced promotion of cell degeneration and loss. Relatively large doses of X-rays that destroy proliferative capacity, have no detectable lethal effect on the maintenance of non-dividing cells. The biological response of nondividing HDF to radiations from different parts of the electromagnetic spectrum is dissimilar. (author)

  3. UV-Vis spectroscopy and solvatochromism of the tyrosine kinase inhibitor AG-1478

    Science.gov (United States)

    Khattab, Muhammad; Wang, Feng; Clayton, Andrew H. A.

    2016-07-01

    The effect of twenty-one solvents on the UV-Vis spectrum of the tyrosine kinase inhibitor AG-1478 was investigated. The absorption spectrum in the range 300-360 nm consisted of two partially overlapping bands at approximately 340 nm and 330 nm. The higher energy absorption band was more sensitive to solvent and exhibited a peak position that varied from 327 nm to 336 nm, while the lower energy absorption band demonstrated a change in peak position from 340 nm to 346 nm in non-chlorinated solvents. The fluorescence spectrum of AG-1478 was particularly sensitive to solvent. The wavelength of peak intensity varied from 409 nm to 495 nm with the corresponding Stokes shift in the range of 64 nm to 155 nm (4536 cm- 1 to 9210 cm- 1). We used a number of methods to assess the relationship between spectroscopic properties and solvent properties. The detailed analysis revealed that for aprotic solvents, the peak position of the emission spectrum in wavenumber scale correlated with the polarity (dielectric constant or ET(30)) of the solvent. In protic solvents, a better correlation was observed between the hydrogen bonding power of the solvent and the position of the emission spectrum. Moreover, the fluorescence quantum yields were larger in aprotic solvents as compared to protic solvents. This analysis underscores the importance of polarity and hydrogen-bonding environment on the spectroscopic properties of AG-1478. These studies will assume relevance in understanding the interaction of AG-1478 in vitro and in vivo.

  4. /UV Synergistic Aging of Polyester Polyurethane Film Modified by Composite UV Absorber

    Directory of Open Access Journals (Sweden)

    Yanzhi Wang

    2013-01-01

    Full Text Available The pure polyester polyurethane (TPU film and the modified TPU (M-TPU film containing 2.0 wt.% inorganic UV absorbers mixture (nano-ZnO/CeO2 with weight ratio of 3 : 2 and 0.5 wt.% organic UV absorbers mixture (UV-531/UV-327 with weight ratio of 1 : 1 were prepared by spin-coating technique. The accelerated aging tests of the films exposed to constant UV radiation of 400 ± 20 µW/cm2 (313 nm with an ozone atmosphere of 100 ± 2 ppm were carried out by using a self-designed aging equipment at ambient temperature and relative humidity of 20%. The aging resistance properties of the films were evaluated by UV-Vis spectra, Fourier transform infrared spectra (FT-IR, photooxidation index, and carbonyl index analysis. The results show that the composite UV absorber has better protection for TPU system, which reduces distinctly the degradation of TPU film. O3/UV aging of the films increases with incremental exposure time. PI and CI of TPU and M-TPU films increase with increasing exposure time, respectively. PI and CI of M-TPU films are much lower than that of TPU film after the same time of exposure, respectively. Distinct synergistic aging effect exists between ozone aging and UV aging when PI and CI are used as evaluation index, respectively. Of course, the formula of these additives needs further improvement for industrial application.

  5. UV Fluorescence Photography of Works of Art : Replacing the Traditional UV Cut Filters with Interference Filters

    Directory of Open Access Journals (Sweden)

    Luís BRAVO PEREIRA

    2010-09-01

    Full Text Available For many years filters like the Kodak Wratten E series, or the equivalent Schneider B+W 415, were used as standard UV cut filters, necessary to obtain good quality on UV Fluorescence photography. The only problem with the use of these filters is that, when they receive the UV radiation that they should remove, they present themselves an internal fluorescence as side effect, that usually reduce contrast and quality on the final image. This article presents the results of our experiences on using some innovative filters, that appeared available on the market in recent years, projected to adsorb UV radiation even more efficiently than with the mentioned above pigment based standard filters: the interference filters for UV rejection (and, usually, for IR rejection too manufactured using interference layers, that present better results than the pigment based filters. The only problem with interference filters type is that they are sensitive to the rays direction and, because of that, they are not adequate to wide-angle lenses. The internal fluorescence for three filters: the B+W 415 UV cut (equivalent to the Kodak Wratten 2E, pigment based, the B+W 486 UV IR cut (an interference type filter, used frequently on digital cameras to remove IR or UV and the Baader UVIR rejection filter (two versions of this interference filter were used had been tested and compared. The final quality of the UV fluorescence images seems to be of a superior quality when compared to the images obtained with classic filters.

  6. On Gauge Invariant Cosmological Perturbations in UV-modified Hořava Gravity: A Brief Introduction

    Science.gov (United States)

    Park, Mu-In

    2018-01-01

    We revisit gauge invariant cosmological perturbations in UV-modified, z = 3 Hořava gravity with one scalar matter field, which has been proposed as a renormalizable gravity theory without the ghost problem in four dimensions. We confirm that there is no extra graviton modes and general relativity is recovered in IR, which achieves the consistency of the model. From the UV-modification terms which break the detailed balance condition in UV, we obtain scale-invariant power spectrums for non-inflationary backgrounds, like the power-law expansions, without knowing the details of early expansion history of Universe. This could provide a new framework for the Big Bang cosmology.

  7. On Gauge Invariant Cosmological Perturbations in UV-modified Hořava Gravity: A Brief Introduction*

    Directory of Open Access Journals (Sweden)

    Park Mu-In

    2018-01-01

    Full Text Available We revisit gauge invariant cosmological perturbations in UV-modified, z = 3 Hořava gravity with one scalar matter field, which has been proposed as a renormalizable gravity theory without the ghost problem in four dimensions. We confirm that there is no extra graviton modes and general relativity is recovered in IR, which achieves the consistency of the model. From the UV-modification terms which break the detailed balance condition in UV, we obtain scale-invariant power spectrums for non-inflationary backgrounds, like the power-law expansions, without knowing the details of early expansion history of Universe. This could provide a new framework for the Big Bang cosmology.

  8. Time dependence of the UV resonance lines in the cataclysmic variables SU UMa, RX And and 0623+71

    International Nuclear Information System (INIS)

    Woods, J.A.; Drew, J.E.; Verbunt, Frank

    1990-01-01

    We present IUE observations of the dwarf novae SU UMa and RX And, and of the nova-like variable 0623 + 71. At the time of observation, SU UMa and RX And were in outburst. All three systems show variability in the wind-formed UV resonance lines of N v λ 1240, Si IV λ 1397 and C IV λ 1549 on timescale of hours. The amplitude of variation is smallest in RX And and largest in 0623 + 71. There is evidence that the variations observed in SU UMa's UV spectrum repeat on the orbital period. Our observations of SU UMa also reveal variability in the continuum flux during the decline from outburst maximum that is much more marked in the UV than at optical wavelengths. (author)

  9. Requirements of blue, UV-A, and UV-B light for normal growth of higher plants, as assessed by actions spectra for growth and related phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, T. [Kobe Women`s Univ., Higashisuma (Japan)

    1994-12-31

    It is very important for experimental purposes, as well as for the practical use of plants when not enough sunlight is available. To grow green higher plants in their normal forms under artificial lighting constructing efficient and economically reasonable lighting systems is not an easy task. One possible approach would be to simulate sunlight in intensity and the radiation spectrum, but its high construction and running costs are not likely to allow its use in practice. Sunlight may be excessive in irradiance in some or all portions of the spectrum. Reducing irradiance and removing unnecessary wavebands might lead to an economically feasible light source. However, removing or reducing a particular waveband from sunlight for testing is not easy. Another approach might be to find the wavebands required for respective aspects of plant growth and to combine them in a proper ratio and intensity. The latter approach seems more practical and economical, and the aim of this Workshop lies in advancing this approach. I summarize our present knowledge on the waveband requirements of higher plants for the regions of blue, UV-A and UV-B.

  10. Clinical spectrum of onchodermatitis

    International Nuclear Information System (INIS)

    Bari, A.U.

    2007-01-01

    To describe the frequency and to see various dermatological presentations of onchocerciasis in black Africans of Sierra Leone. Local black patients of all age groups, attending dermatology outpatient department of Pak Field Hospital (established as a part of UN peacekeeping mission in Sierra Leone) with clinical diagnosis of onchodermatitis, based on symptomatology and morphological features of the disease, were included. UN troops were excluded. Laboratory investigations including blood complete picture and skin snips were carried out in all patients. Skin biopsy and nodule biopsy was performed in selected cases. Skin manifestations were recorded and categorized into various clinical patterns, i.e. acute, chronic, lichenified, onchocercoma, etc. Data was analyzed by using descriptive statistics in Instat. A total of 3011 patients, belonging to different local tribes, having a variety of skin disorders, were seen during the study period. One hundred and eighty-seven (6.2%) patients were found to have onchodermatitis. Patients were of all ages and both sexes, their ages ranging from 1 month to 73 years. Gender ratio was almost equal. A whole clinical spectrum of onchodermatitis was observed, chronic papular onchodermatitis being the most common pattern. Onchodermatitis with a large spectrum of clinical manifestations was seen in black Africans of the eastern part of Sierra Leone. (author)

  11. Supernovae anisotropy power spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Ghodsi, Hoda; Baghram, Shant [Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Habibi, Farhang, E-mail: h.ghodsi@mehr.sharif.ir, E-mail: baghram@sharif.edu, E-mail: habibi@lal.in2p3.fr [LAL-IN2P3/CNRS, BP 34, 91898 Orsay Cedex (France)

    2017-10-01

    We contribute another anisotropy study to this field of research using Type Ia supernovae (SNe Ia). In this work, we utilise the power spectrum calculation method and apply it to both the current SNe Ia data and simulation. Using the Union2.1 data set at all redshifts, we compare the spectrum of the residuals of the observed distance moduli to that expected from an isotropic universe affected by the Union2.1 observational uncertainties at low multipoles. Through this comparison we find a dipolar anisotropy with tension of less that 2σ towards l = 171° ± 21° and b = −26° ± 28° which is mainly induced by anisotropic spatial distribution of the SNe with z > 0.2 rather than being a cosmic effect. Furthermore, we find a tension of ∼ 4σ at ℓ = 4 between the two spectra. Our simulations are constructed with the characteristics of the upcoming surveys like the Large Synoptic Survey Telescope (LSST), which shall bring us the largest SNe Ia collection to date. We make predictions for the amplitude of a possible dipolar anisotropy that would be detectable by future SNe Ia surveys.

  12. Spectral dependence of some UV-B and UV-C responses of Tetrahymena pyriformis irradiated with dye laser generated UV

    International Nuclear Information System (INIS)

    Calkins, John; Colley, Ed; Wheeler, John; Kentucky Univ., Lexington

    1987-01-01

    We have generated UV-B and UV-C radiations using a flashlamp driven tunable dye laser combined with frequency doubling crystals. Using this novel UV source, we have investigated lethality and its modification by growth phase, photoreactivation and caffeine in Tetrahymena pyriformis at 254 nm and from 260-315 nm in 5 nm steps. From the observed responses we have constructed action spectra for lethality, with or without caffeine (a repair inhibitor) and under conditions of photoreactivation. We have also estimated quantum efficiencies for these responses. Our observations suggest that complex changes in response occur at several wavelengths over the UV-C and UV-B regions. (author)

  13. UV effects on bottom ice algae

    International Nuclear Information System (INIS)

    Ryan, K.; Buckley, B.

    1993-01-01

    Antarctic sea ice can be surprisingly transparent to UV radiation, particularly during spring when ozone depletion reaches a maximum. A 5% reduction in photosynthetic production was observed in laboratory experiments for UVB levels expected under the ice at this time. In situ studies modifying the UVB radiation falling onto algae were inconclusive. (author). 5 refs

  14. a near ambient pressure UV photoelectron spectroscopy

    Indian Academy of Sciences (India)

    Manoj Kumar Ghosalya

    2018-03-02

    Mar 2, 2018 ... UV photoelectron spectroscopy (NAP-UPS) investigations. MANOJ KUMAR ... gations led to various models of Ag-O2 interaction to explain its role in the .... charge lamp (for He I and He II excitations) are available as photon ...

  15. DNA N-glycosylases and uv repair

    Energy Technology Data Exchange (ETDEWEB)

    Demple, B; Linn, S

    1980-09-18

    Repair of some DNA photoproducts can be mediated by glycosylic bond hydrolysis. Thus, Escherichia coli endonuclease III releases 5,6-hydrated thymines as free bases, while T4 uv endonuclease releases one of two glycosylic bonds holding pyrimidine dimers in DNA. In contrast, uninfected E. coli apparently does not excise pyrimidine dimers via a DNA glycosylase.

  16. A Mode Locked UV-FEL

    CERN Document Server

    Parvin, Parviz

    2004-01-01

    An appropriate resonator has been designed to generate femtosecond mode locked pulses in a UV FEL with the modulator performance based on the gain switching. The gain broadening due to electron energy spread affects on the gain parameters, small signal gain (γ0) and saturation intensity (Is), to determine the optimum output coupling as small.

  17. UV Defined Nanoporous Liquid Core Waveguides

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Gopalakrishnan, Nimi; Ndoni, Sokol

    2011-01-01

    Nanoporous liquid core waveguides, where both core and cladding are made from the same material, are presented. The nanoporous polymer used is intrinsically hydrophobic, but selective UV exposure enables it to infiltrate with an aqueous solution, thus raising the refractive index from 1.26 to 1...

  18. Exposure to phenols, parabens and UV filters

    DEFF Research Database (Denmark)

    Joensen, Ulla N.; Jørgensen, Niels; Thyssen, Jacob P.

    2017-01-01

    Concentrations of eight simple phenols, six parabens and nine UV filters were analysed in urine from 65 FLG loss-of-function mutation carriers and 130 non-carriers (controls). Regression analyses, controlling for urinary dilution and confounders, were performed to estimate associations between FLG mutation...

  19. uv keratoconjunctivitis vs. established dose effect relationships

    International Nuclear Information System (INIS)

    Gulvady, N.U.

    1976-01-01

    A patient who received a uv dose to his eyes 11 times greater than the photokeratitic threshold of Pitts and 4 1 / 2 times the photokeratitic threshold as found by Leach. The patient had severe keratoconjunctivitis for 3 days and did not develop any keratitis

  20. Airborne pipeline leak detection: UV or IR?

    Science.gov (United States)

    Babin, François; Gravel, Jean-François; Allard, Martin

    2016-05-01

    This paper presents a study of different approaches to the measurement of the above ground vapor plume created by the spill caused by a small 0.1 l/min (or less) leak in an underground liquid petroleum pipeline. The scenarios are those for the measurement from an airborne platform. The usual approach is that of IR absorption, but in the case of liquid petroleum products, there are drawbacks that will be discussed, especially when using alkanes to detect a leak. The optical measurements studied include UV enhanced Raman lidar, UV fluorescence lidar and IR absorption path integrated lidars. The breadboards used for testing the different approaches will be described along with the set-ups for leak simulation. Although IR absorption would intuitively be the most sensitive, it is shown that UV-Raman could be an alternative. When using the very broad alkane signature in the IR, the varying ground spectral reflectance are a problem. It is also determined that integrated path measurements are preferred, the UV enhanced Raman measurements showing that the vapor plume stays very close to the ground.

  1. UV-LED Curing Efficiency of Wood Coatings

    OpenAIRE

    Véronic Landry; Pierre Blanchet; Gabrielle Boivin; Jean-François Bouffard; Mirela Vlad

    2015-01-01

    Ultraviolet light emitting diodes (UV-LEDs) have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerf...

  2. 207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

    Full Text Available BACKGROUND: 0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ~200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure. AIMS: The aim of this work was to test the biophysically-based hypothesis that ~200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues. METHODS: A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts were measured, for both UV radiations incident on 3-D human skin tissue. RESULTS: We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp. CONCLUSIONS: As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively

  3. 207-nm UV light - a promising tool for safe low-cost reduction of surgical site infections. I: in vitro studies.

    Science.gov (United States)

    Buonanno, Manuela; Randers-Pehrson, Gerhard; Bigelow, Alan W; Trivedi, Sheetal; Lowy, Franklin D; Spotnitz, Henry M; Hammer, Scott M; Brenner, David J

    2013-01-01

    0.5% to 10% of clean surgeries result in surgical-site infections, and attempts to reduce this rate have had limited success. Germicidal UV lamps, with a broad wavelength spectrum from 200 to 400 nm are an effective bactericidal option against drug-resistant and drug-sensitive bacteria, but represent a health hazard to patient and staff. By contrast, because of its limited penetration, ~200 nm far-UVC light is predicted to be effective in killing bacteria, but without the human health hazards to skin and eyes associated with conventional germicidal UV exposure. The aim of this work was to test the biophysically-based hypothesis that ~200 nm UV light is significantly cytotoxic to bacteria, but minimally cytotoxic or mutagenic to human cells either isolated or within tissues. A Kr-Br excimer lamp was used, which produces 207-nm UV light, with a filter to remove higher-wavelength components. Comparisons were made with results from a conventional broad spectrum 254-nm UV germicidal lamp. First, cell inactivation vs. UV fluence data were generated for methicillin-resistant S. aureus (MRSA) bacteria and also for normal human fibroblasts. Second, yields of the main UV-associated pre-mutagenic DNA lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) were measured, for both UV radiations incident on 3-D human skin tissue. We found that 207-nm UV light kills MRSA efficiently but, unlike conventional germicidal UV lamps, produces little cell killing in human cells. In a 3-D human skin model, 207-nm UV light produced almost no pre-mutagenic UV-associated DNA lesions, in contrast to significant yields induced by a conventional germicidal UV lamp. As predicted based on biophysical considerations, 207-nm light kills bacteria efficiently but does not appear to be significantly cytotoxic or mutagenic to human cells. Used appropriately, 207-nm light may have the potential for safely and inexpensively reducing surgical-site infection rates, including those of drug

  4. Dichotomy in response to indomethacin in uv-C and uv-B induced ultraviolet light inflammation

    International Nuclear Information System (INIS)

    Eaglstein, W.H.; Marsico, A.R.

    1975-01-01

    In subjects irradiated with both UV-C and UV-B ultraviolet light (UVL), 10 μg of intradermal indomethacin decreased the redness in all 13 of the UV-B irradiated areas but in only 2 of 13 of the UV-C irradiated areas. Higher doses of intradermal indomethacin (50 μg and 100 μg) decreased the redness produced by UV-C irradiation in 6 subjects. It is suggested that the failure of 10 μg of indomethacin to decrease the redness of the UV-C induced inflammation, while decreasing the redness in the UV-B induced inflammation, is consistent with the possibility that prostaglandins participate in UV-B but not UV-C induced inflammation

  5. Age-related changes of DNA methylation in cotyledonous leaves of Linum usitatissimum under UV-B radiation

    International Nuclear Information System (INIS)

    Berestyana, A.M.; Grodzins'kij, D.M.; Kryipka, G.V.

    2011-01-01

    The age-related changes of DNA methylation in cotyledonous leaves of Linum usitatissimum subjected to UV-B radiation in the interval 4.23-12.69 kJ/m 2 have been studied. The level of methylation is determined by the restriction analysis. Although the study showed no dose-dependence, some methylation spectrum changes in the process of aging of the Linum usitatissimum cotyledonous leaves occurred.

  6. UV-Radiation: From Physics to Impacts

    Directory of Open Access Journals (Sweden)

    Hanns Moshammer

    2017-02-01

    Full Text Available Ultraviolet (UV radiation has affected life at least since the first life forms moved out of the seas and crawled onto the land. Therefore, one might assume that evolution has adapted to natural UV radiation. However, evolution is mostly concerned with the propagation of the genetic code, not with a long, happy, and fulfilling life. Because rickets is bad for a woman giving birth, the beneficial effects of UV-radiation outweigh the adverse effects like aged skin and skin tumors of various grades of malignancy that usually only afflict us at older age. Anthropogenic damage to the stratospheric ozone layer and frighteningly high rates of melanoma skin cancer in the light-skinned descendants of British settlers in Australia piqued interest in the health impacts of UV radiation. A changing cultural perception of the beauty of tanned versus light skin and commercial interests in selling UV-emitting devices such as tanning booths caught public health experts off-guard. Counseling and health communication are extremely difficult when dealing with a “natural” risk factor, especially when this risk factor cannot (and should not be completely avoided. How much is too much for whom or for which skin type? How even measure “much”? Is it the (cumulative dose or the dose rate that matters most? Or should we even construct a more complex metric such as the cumulative dose above a certain dose rate threshold? We find there are still many open questions, and we are glad that this special issue offered us the opportunity to present many interesting aspects of this important topic.

  7. Thermoluminescence sensitivity of ulexite after UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Topaksu, M., E-mail: mats@cu.edu.tr [Cukurova University, Arts-Sciences Faculty, Physics Department, 01330 Adana (Turkey); CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, (CSIC), C/José Gutiérrez Abascal 2, 28006 Madrid (Spain)

    2015-04-15

    Highlights: •UV-induced thermoluminescence emission of Turkish ulexite was studied. •There are three groups of components. •The UV exposures were performed at controlled temperatures. -- Abstract: The effects of UV radiation on the thermoluminescence (TL) properties of natural materials, in contrast to synthetic materials, have been scarcely studied. We report on the UV-induced thermoluminescence emission of a Turkish ulexite (NaCaB{sub 5}O{sub 6}(OH){sub 6}·5H{sub 2}O) that displays very complex TL glow curves, with at least three groups of components peaked at 130–140 °C, 240 °C and, 340 °C, wherein the last group is weaker. Such emission could be associated with structural changes in the lattice as well as alkali self-diffusion processes. The UV exposure performed at controlled temperatures (at room temperature (RT), 50 °C and 100 °C) produced a (i) different evolutions of the intensities of each maximum, which are directly related to the controlled thermal treatment; (ii) different intensity ratios among the groups of components; (iii) different activation energies (E{sub a}) (1.13 eV for RT, 0.99 eV for 50 °C and 0.49 eV for 100 °C) calculated using the initial rise method; and (iv) similar scattering values (12.4%, 8.2% and 12.8%), which were not a function of the controlled temperature. The thermal stability tests conducted on this borate at different temperatures, based on the T{sub stop} protocol, confirm the presence of a continuum in the distribution of the trap system with progressively increasing E{sub a} (from 0.60 to 0.90 eV)

  8. Waterborne UV coating for industrial applications

    International Nuclear Information System (INIS)

    Bhattacharya, I.N.

    2007-01-01

    (Full Text): Solvent borne industrial coatings are being replaced by environment friendly coatings like Ultra Violet (UV) or Electron Beam (Eb) cured coatings, Powder coatings and Waterborne coatings. Waterborne systems enjoy the biggest share from this shift. UV and EB coatings provide the advantages of instant cure at room temperature, high scratch and abrasion resistance combined with excellent chemical resistance. Polyurethane (PU) chemistry is the dominant chemistry in Industrial coatings as they provide a very high level of performance. Most PU coatings are solvent based 2-component systems comprising of a resin and a cross linker. Polyurethane dispersions (PUD) in water in single pack are available but mainly addresses the Do It Yourself (DIY) market because of their slow drying speeds. Performance of PUD in most cases is inferior to solvent borne 2-component PU systems.Therefore the combination of PU dispersion and UV/EB curable technology has led to new innovative waterborne polymers called UV curable polyurethane dispersions (UVPUD). UVPUD are zero VOC systems as they are coalescent free. They are higher in molecular weight than standard UV curable products resulting in lower shrinkage coatings and provide good adhesion to substrates. Their low-viscosity makes them suitable for application by spray, curtain coater and even roller coater, without having to use monomers. UVPUD display superior chemical and mechanical properties necessary to protect high quality surface from the challenging usage conditions. UVPUD resins are therefore tailor-made to address performance needs like excellence in outdoor durability, scratch resistance, stain resistance, adhesion etc. UVPUD technology is now growing rapidly in industrial coatings for applications such as resilient flooring, wooden parquet flooring, automotive interior plastics, mobile phones etc. (Author)

  9. IR-safe and UV-safe integrands in the EFTofLSS with exact time dependence

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowski, Matthew [Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS, 91191 Gif-sur-Yvette (France); Senatore, Leonardo, E-mail: matthew.lewandowski@ipht.fr, E-mail: senatore@stanford.edu [Stanford Institute for Theoretical Physics, Stanford University, Stanford, 94306 CA (United States)

    2017-08-01

    Because large-scale structure surveys may very well be the next leading sources of cosmological information, it is important to have a precise understanding of the cosmological observables; for this reason, the Effective Field Theory of Large-Scale Structure (EFTofLSS) was developed. So far, most results in the EFTofLSS have used the so-called Einstein-de Sitter approximation, an approximation of the time dependence which is known to be accurate to better than one percent. However, in order to reach even higher accuracy, the full time dependence must be used. The computation with exact time dependence is sensitive to both infrared (IR) and ultraviolet (UV) effects in the loop integrands, and while these effects must cancel because of diffeomorphism invariance, they make numerical computation much less efficient. We provide a formulation of the one-loop, equal-time exact-time-dependence power spectrum of density perturbations which is manifestly free of these spurious IR and UV divergences at the level of the integrand. We extend our results to the total matter mode with clustering quintessence, show that IR and UV divergences cancel, and provide the associated IR- and UV-safe integrand. This also establishes that the consistency conditions are satisfied in this system. We then use our one-loop result to do an improved precision comparison of the two-loop dark-matter power spectrum with the Dark Sky N -body simulation.

  10. Toxicological Assessment and UV/TiO2-Based Induced Degradation Profile of Reactive Black 5 Dye

    Science.gov (United States)

    Bilal, Muhammad; Rasheed, Tahir; Iqbal, Hafiz M. N.; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

    2018-01-01

    In this study, the toxicological and degradation profile of Reactive Black 5 (RB5) dye was evaluated using a UV/TiO2-based degradation system. Fourier transform infrared spectroscopy (FT-IR), thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) techniques were used to evaluate the degradation level of RB5. The UV-Vis spectral analysis revealed the disappearance of peak intensity at 599 nm (λmax). The FT-IR spectrum of UV/TiO2 treated dye sample manifest appearance of new peaks mainly because of the degraded product and/or disappearance of some characteristics peaks which were present in the untreated spectrum. The HPLC profile verified the RB5 degradation subject to the formation of metabolites at different retention times. A stable color removal higher than 96% with COD removal in the range of 74-82.3% was noted at all evaluated dye concentrations. The tentative degradation pathway of RB5 is proposed following a careful analysis of the intermediates identified by UPLC-MS. Toxicity profile of untreated and degraded dye samples was monitored using three types of human cell lines via MTT assay and acute toxicity testing with Artemia salina. In conclusion, the UV/TiO2-based degradation system could be effectively employed for the remediation of textile wastewater comprising a high concentration of reactive dyes.

  11. Dependence of biologically active UV radiation on the atmospheric ozone in 2000 - 2001 over Stara Zagora, Bulgaria

    International Nuclear Information System (INIS)

    Gogosheva, Tz.; Petkov, B.; Mendeva, B.; Krastev, D.

    2003-01-01

    This study investigates how the changes in simultaneously measured ozone columns influence the biologically active UV irradiance. Spectral ground-based measurements of direct solar ultraviolet radiation performed at Stara Zagora (42 o N, 25 o E), Bulgaria in 2000 - 2001 are used in conjunction with the total ozone content to investigate the relation to the biologically active UV radiation, depending on the solar zenith angle (SZA) and the ozone. The device measures the direct solar radiation in the range 290 - 360 nm at 1 nm resolution. The direct sun UV doses for some specific biological effects (erythema and eyes) are obtained as the integral in the wavelength interval between 290 and 330 nm of the UV solar spectrum weighted with an action spectrum, typical of each effect. For estimation of the sensitivity of biological doses to the atmospheric ozone we calculate the radiation amplification factor (RAF) defined as the percentage increase in the column amount of the atmospheric ozone. The biological doses increase significantly with the decrease of the SZA. The doses of SZA=20 o are about three times larger than doses at SZA=50 o . The RAF derived from our spectral measurements shows an increase of RAF along with the decreasing ozone. For example, the ozone reduction by 1% increases the erythemal dose by about 2%. (authors)

  12. Comparison of UV action spectra for lethality and mutation in Salmonella typhimurium using a broad band source and monochromatic radiations

    International Nuclear Information System (INIS)

    Calkins, John; Selby, Christopher; Enoch, H.G.

    1987-01-01

    The UV-B region (280-320 nm) is thought to be primarily responsible for the mutagenic, lethal, and carcinogenic effects of solar radiation. We have conducted UV-B action spectroscopy for mutagenesis and survival of Ames' Salmonella typhimurium strain TA98 (uvrB, pKM101) using both monochromatic radiation from a dye laser and broader bandwidth radiation emitted from FS-20 sunlamps. A series of optical filters having different transmission cut-offs together with the sunlamp source provided bandwidths having successively less short wavelength components from which a ''broad band'' action spectrum was deduced. The two sets of action spectra differed both qualitatively and quantitatively: in comparison to the monochromatic action spectra, the ''broad band'' spectra showed up to a 200-fold reduced efficiency for both mutation induction and lethality by UV-B wavelengths. These results suggest a large protective effect of the background UV-A and/or visible radiations which were present during the broad spectrum irradiations and which are also present in solar radiation. Additional experiments show that to the extent tested this protective effect is not due to photo-reactivation or irradiance (dose rate) effects. (author)

  13. Row orientation effect on UV-B, UV-A and PAR solar irradiation components in vineyards at Tuscany, Italy

    Science.gov (United States)

    Grifoni, D.; Carreras, G.; Zipoli, G.; Sabatini, F.; Dalla Marta, A.; Orlandini, S.

    2008-11-01

    Besides playing an essential role in plant photosynthesis, solar radiation is also involved in many other important biological processes. In particular, it has been demonstrated that ultraviolet (UV) solar radiation plays a relevant role in grapevines ( Vitis vinifera) in the production of certain important chemical compounds directly responsible for yield and wine quality. Moreover, the exposure to UV-B radiation (280-320 nm) can affect plant-disease interaction by influencing the behaviour of both pathogen and host. The main objective of this research was to characterise the solar radiative regime of a vineyard, in terms of photosynthetically active radiation (PAR) and UV components. In this analysis, solar spectral UV irradiance components, broadband UV (280-400 nm), spectral UV-B and UV-A (320-400 nm), the biological effective UVBE, as well as the PAR (400-700 nm) component, were all considered. The diurnal patterns of these quantities and the UV-B/PAR and UV-B/UV-A ratios were analysed to investigate the effect of row orientation of the vineyard in combination with solar azimuth and elevation angles. The distribution of PAR and UV irradiance at various heights of the vertical sides of the rows was also studied. The results showed that the highest portion of plants received higher levels of daily radiation, especially the UV-B component. Row orientation of the vines had a pronounced effect on the global PAR received by the two sides of the rows and, to a lesser extent, UV-A and UV-B. When only the diffused component was considered, this geometrical effect was greatly attenuated. UV-B/PAR and UV-A/PAR ratios were also affected, with potential consequences on physiological processes. Because of the high diffusive capacity of the UV-B radiation, the UV-B/PAR ratio was significantly lower on the plant portions exposed to full sunlight than on those in the shade.

  14. Photofragment spectrum of acetone

    International Nuclear Information System (INIS)

    Hancock, Graham; Wilson, K.R.

    1974-01-01

    The photodissociation of acetone at 266.2 nm has been investigated by photofragment spectroscopy. A molecular beam of CH 3 COCH 3 is crossed by pulses of polarized uv light from a powerful fourth harmonic neodymium laser system, and the recoiling CH 3 and CH 3 CO photofragments detected with a quadrupole mass spectrometer. Both the flight time distributions and the masses of the fragments are measured, leading to a determination of the energy partitioning in the photodissociation process; it is found that the methyl and acetyl fragments together carry 43% of the available energy in translation, with the remaining 57% in fragment internal excitation. The angular distribution of fragments with respect to the polarization direction of the laser beam was found to be isotropic. The long lifetime of the initially produced singlet state should give a smoothing of the angular distribution, and this tendency towards isotropy could be further increased by a non-planar mode of dissociation of the excited molecule. Both statistical and impulsive dissociation models can fit the observed average energy partitioning, with present data enable to distinguish between the two possibilities, which, however, could be differentiated with further crossed molecular and laser beam experiments

  15. Aluminum Mirror Coatings for UVOIR Telescope Optics Including the Far UV

    Science.gov (United States)

    Balasubramanian, Kunjithapatha; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Ayala, Michael; Shaklan, Stuart; Scowen, Paul; Del Hoyo, Javier; Quijada, Manuel

    2015-01-01

    NASA Cosmic Origins (COR) Program identified the development of high reflectivity mirror coatings for large astronomical telescopes particularly for the far ultra violet (FUV) part of the spectrum as a key technology requiring significant materials research and process development. In this paper we describe the challenges and accomplishments in producing stable high reflectance aluminum mirror coatings with conventional evaporation and advanced Atomic Layer Deposition (ALD) techniques. We present the current status of process development with reflectance of approx. 55 to 80% in the FUV achieved with little or no degradation over a year. Keywords: Large telescope optics, Aluminum mirror, far UV astrophysics, ALD, coating technology development.

  16. Transmission of UV-irradiance into nectarine fruit

    International Nuclear Information System (INIS)

    Blanke, M.M.

    1996-01-01

    With the global depletion of the ozone layer, leaves and fruits are increasingly exposed to UV-irradiance on the tree. Some fruits are additionally exposed postharvest to artificial germicidal W-irradiance, leading to a cumulative effect. This paper examines the transmission of UV-light (200-400 nm) by the peel of ripe nectarine fruit using UV/VIS spectrophotometry to aid understanding of UV-effects and assess the sensitivity of the peel to UV wavelengths. Yellow peel of nectarine fruit transmitted less than 0.1 % in the UV-C range of 220 to 280 nm. With longer wavelenghts, UV-light transmission increased slowly from 0.4 % at 284 nm to 1.6 % at 320 nm and, in the UV-A region, progressively from 1.9 % at 330 nm to a maximum of 13 % of incident irradiance at 400 nm. Red peel of nectarine fruit transmitted less than 0.1 % of UV-C and UV-B light, but up to 0.9 % of incident UV-A light at 400 nm. Conversely, UV-absorption of nectarine peel decreased with longer wavelengths. Hence, fruit parenchyma is more affected by UV-irradiance at wavelengths above ca. 280 nm and underneath yellow than underneath red peel

  17. UV-sensitivity and repair of UV-damage in Salmonella of wild type

    International Nuclear Information System (INIS)

    Kondratiev, Y.S.; Brukhansky, G.V.; Andreeva, I.V.; Skavronskaya, A.G.

    1977-01-01

    The UV-sensitivity of wild type Salmonella strains has been compared to that of wild type E.coli and its UV-sensitive mutants. Many wild type Salmonella strains are 4-5 times more sensitive than wild type E.coli and their inactivation curve is similar to that for E.coli with a mutation in the polA gene. Alkaline sucrose gradient centrifugation has shown a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a Salmonella genus feature because one strain as resistant as wild type E.coli was found. This resistant strain showed normal excision repair in alkaline sucrose gradient centrifugation experiments. The possible influence of plasmids and mutations in repair genes on the ability of Salmonella to repair UV-damaged DNA is discussed. (orig.) [de

  18. UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces

    International Nuclear Information System (INIS)

    Lochmann, E.R.; Lochmann, G.

    1997-01-01

    The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.) [de

  19. UV-sensitivity and repair of UV-damage in Salmonella of wild type

    Energy Technology Data Exchange (ETDEWEB)

    Kondratiev, Y S; Brukhansky, G V; Andreeva, I V; Skavronskaya, A G [Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Ehpidemiologii i Mikrobiologii

    1977-12-01

    The UV-sensitivity of wild type Salmonella strains has been compared to that of wild type E.coli and its UV-sensitive mutants. Many wild type Salmonella strains are 4-5 times more sensitive than wild type E.coli and their inactivation curve is similar to that for E.coli with a mutation in the polA gene. Alkaline sucrose gradient centrifugation has shown a deficiency of these strains in normal excision repair of UV-damaged DNA. This deficiency is not a Salmonella genus feature because one strain as resistant as wild type E.coli was found. This resistant strain showed normal excision repair in alkaline sucrose gradient centrifugation experiments. The possible influence of plasmids and mutations in repair genes on the ability of Salmonella to repair UV-damaged DNA is discussed.

  20. Effect of uvs1, uvs2 and xrs mutations on the radiosensitivity and the induced mitotic recombination frequency in diploid yeast cells

    International Nuclear Information System (INIS)

    Suslova, N.G.; Fedorova, I.V.; Zheleznyakova, N.Yu.

    1975-01-01

    The influence of the loci of radiosensitivity uvs1, uvs2, and xrs in the homozygous state at the diploid level on the sensitivity to UV and ionizing radiation and induced mitotic recombination was studied in the yeast Sacch. cerevisiae. Hypersensitivity to UV irradiation was detected in the diploids uvs2 uvs2 xrs xrs in comparision with the corresponding control. The diploid uvs1 uvs1 uvs2 uvs2 does not differ in UV sensitivity from the diploid uvs1 uvs1 UVS2 UVS2. These facts demonstrate that the uvs1 and uvs2 mutations, on the one hand, and the xrs mutations, on the other, normally control different pathways of elimination of UV-induced damages. It was shown that the diploid uvs2 uvs2 xrs3 xrs3 is far more sensitive to the lethal action of x rays than the control diploid UVS2 UVS2 xrs3 xrs3. Consequently, the mutations uvs2 and xrs3 block different modes of repair of damages induced by ionizing radiation. In all the double-mutant diploids, the frequency of mitotic recombination induced by UV rays increases sharply in comparison with that of the radioresistant diploids UVS UVS XRS XRS and the UV-sensitive diploids uvs2 uvs2 XRS XRS. Possible causes of the observed phenomenon are discussed. It was established that in a diploid homozygous for the loci uvs2 xrs5, the frequency of mitotic recombination induced by x rays increases extremely sharply. This fact confirms the hypothesis that the gene product of the locus uvs2 participates in the repair of DNA after the action of ionizing radiation. (author)

  1. Influence of photosynthetically active radiation and spectral quality on UV-B-induced polyamine accumulation in soybean

    International Nuclear Information System (INIS)

    Kramer, G.F.; Krizek, D.T.; Mirecki, R.M.

    1992-01-01

    UV-B-sensitive (Essex) and -insensitive (Williams) cultivars of soybean (Glycine max) were grown in growth chambers at photosynthetically active radiation (PAR) levels of 300 or 600 μmol m −2 sec −1 provided by either red- and far-red-deficient (MH) or blue-deficient (HPS/DX) lamps or a combination of both. The combined treatment provided a balanced output, similar to that provided by fluorescent plus incandescent lighting across the visible spectrum. Under the combined lamps, plants were exposed to 12 kJ m −2 day −1 of biologically effective UV-B (UV-B BE ) with 6-hr irradiance periods centred midway through the photoperiod. This irradiance corresponded to a decrease in stratospheric ozone of ca 20% for clear sky conditions at Beltsville, MD on 21 June. Plant growth was significantly inhibited by UV-B at 300 but not at 600 μmol m −2 sec −1 PAR. No cultivar differences were noted in the UV-B-induced inhibition of growth, although visible injury was less in Williams than in Essex. PAR had a large effect on polyamine levels in leaves, with higher levels of putrescine (Put) and spermidine observed at 600 than at 300 μmol m −2 sec −1 in both cultivars. UV-B-induced polyamine accumulation was observed primarily in Williams. Under MH or HPS/DX lamps alone, plants were exposed to two different UV-B levels, 9.9 and 12 kJ m −2 day −1 , corresponding to stratospheric ozone reductions of ca 9 and 20%. UV-B inhibited growth at both 300 and 600 μmol m −2 sec −1 PAR under either radiation source. There was no effect of PAR on the UV-B-induced growth inhibition with the HPS/DX lamps, but a partial amelioration of this inhibition occurred in Williams at 600 μmol m −2 sec −1 PAR under MH lamps. Dose-dependent UV-B-induced polyamine accumulation was also observed in both cultivars. PAR increased Put levels under MH but not HPS/DX lamps. These results indicate that the inhibition of UV-B stress by high PAR may require a balance of red and blue

  2. Photodegradation of sulfasalazine and its human metabolites in water by UV and UV/peroxydisulfate processes.

    Science.gov (United States)

    Ji, Yuefei; Yang, Yan; Zhou, Lei; Wang, Lu; Lu, Junhe; Ferronato, Corinne; Chovelon, Jean-Marc

    2018-04-15

    The widespread occurrence of pharmaceuticals and their metabolites in natural waters has raised great concerns about their potential risks on human health and ecological systems. This study systematically investigates the degradation of sulfasalazine (SSZ) and its two human metabolites, sulfapyridine (SPD) and 5-aminosalicylic acid (5-ASA), by UV and UV/peroxydisulfate (UV/PDS) processes. Experimental results show that SPD and 5-ASA were readily degraded upon UV 254 nm direct photolysis, with quantum yields measured to be (8.6 ± 0.8) × 10 -3 and (2.4 ± 0.1) × 10 -2  mol Einstein -1 , respectively. Although SSZ was resistant to direct UV photolysis, it could be effectively removed by both UV/H 2 O 2 and UV/PDS processes, with fluence-based pseudo-first-order rate constants determined to be 0.0030 and 0.0038 cm 2  mJ -1 , respectively. Second-order rate constant between SO 4 •- and SSZ was measured as (1.33 ± 0.01) × 10 9  M -1 s -1 by competition kinetic method. A kinetic model was established for predicting the degradation rate of SSZ in the UV/PDS process. Increasing the dosage of PDS significantly enhanced the degradation of SSZ in the UV/PDS process, which can be well predicted by the developed kinetic model. Natural water constituents, such as natural organic matter (NOM) and bicarbonate (HCO 3 - ), influenced the degradation of SSZ differently. The azo functional group of SSZ molecule was predicted as the reactive site susceptible to electrophilic attack by SO 4 •- by frontier electron densities (FEDs) calculations. Four intermediate products arising from azo bond cleavage and SO 2 extrusion were identified by solid phase extraction-liquid chromatography-triple quadrupole mass spectrometry (SPE-LC-MS/MS). Based on the products identified, detailed transformation pathways for SSZ degradation in the UV/PDS system were proposed. Results reveal that UV/PDS could be an efficient approach for remediation of water

  3. Autism Spectrum Disorders

    Directory of Open Access Journals (Sweden)

    Rebecca E. Rosenberg

    2011-01-01

    Full Text Available We used a national online registry to examine variation in cumulative prevalence of community diagnosis of psychiatric comorbidity in 4343 children with autism spectrum disorders (ASD. Adjusted multivariate logistic regression models compared influence of individual, family, and geographic factors on cumulative prevalence of parent-reported anxiety disorder, depression, bipolar disorder, and attention deficit/hyperactivity disorder or attention deficit disorder. Adjusted odds of community-assigned lifetime psychiatric comorbidity were significantly higher with each additional year of life, with increasing autism severity, and with Asperger syndrome and pervasive developmental disorder—not otherwise specified compared with autistic disorder. Overall, in this largest study of parent-reported community diagnoses of psychiatric comorbidity, gender, autistic regression, autism severity, and type of ASD all emerged as significant factors correlating with cumulative prevalence. These findings could suggest both underlying trends in actual comorbidity as well as variation in community interpretation and application of comorbid diagnoses in ASD.

  4. Electromagnetic spectrum management system

    Science.gov (United States)

    Seastrand, Douglas R.

    2017-01-31

    A system for transmitting a wireless countermeasure signal to disrupt third party communications is disclosed that include an antenna configured to receive wireless signals and transmit wireless counter measure signals such that the wireless countermeasure signals are responsive to the received wireless signals. A receiver processes the received wireless signals to create processed received signal data while a spectrum control module subtracts known source signal data from the processed received signal data to generate unknown source signal data. The unknown source signal data is based on unknown wireless signals, such as enemy signals. A transmitter is configured to process the unknown source signal data to create countermeasure signals and transmit a wireless countermeasure signal over the first antenna or a second antenna to thereby interfere with the unknown wireless signals.

  5. Rotational spectrum of tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, M. Eugenia, E-mail: maria.sanz@kcl.ac.uk; Cabezas, Carlos, E-mail: ccabezas@qf.uva.es; Mata, Santiago, E-mail: santiago.mata@uva.es; Alonso, Josè L., E-mail: jlalonso@qf.uva.es [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, 47011 Valladolid (Spain)

    2014-05-28

    The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the {sup 14}N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O–H···N hydrogen bond in the side chain and a N–H···π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

  6. Electromagnetic spectrum management system

    Energy Technology Data Exchange (ETDEWEB)

    Seastrand, Douglas R.

    2017-10-17

    A system for transmitting a wireless countermeasure signal to disrupt third party communications is disclosed that include an antenna configured to receive wireless signals and transmit wireless counter measure signals such that the wireless countermeasure signals are responsive to the received wireless signals. A receiver processes the received wireless signals to create processed received signal data while a spectrum control module subtracts known source signal data from the processed received signal data to generate unknown source signal data. The unknown source signal data is based on unknown wireless signals, such as enemy signals. A transmitter is configured to process the unknown source signal data to create countermeasure signals and transmit a wireless countermeasure signal over the first antenna or a second antenna to thereby interfere with the unknown wireless signals.

  7. Spectrum of physics comprehension

    International Nuclear Information System (INIS)

    Blasiak, W; Godlewska, M; Rosiek, R; Wcislo, D

    2012-01-01

    The paper presents the results of research on the relationship between self-assessed comprehension of physics lectures and final grades of junior high school students (aged 13-15), high school students (aged 16-18) and physics students at the Pedagogical University of Cracow, Poland (aged 21). Students' declared level of comprehension was measured during a physics lecture on a prearranged scale of 1-10 with the use of a personal response system designed for the purpose of this experiment. Through the use of this tool, we obtained about 2000 computer records of students' declared comprehension of a 45 min lecture, which we named ‘the spectrum of comprehension’. In this paper, we present and analyse the correlation between students' declared comprehension of the content presented in the lecture and their final learning results. (paper)

  8. Influence of interconnection on the long-term reliability of UV LED packages

    Science.gov (United States)

    Nieland, S.; Mitrenga, D.; Karolewski, D.; Brodersen, O.; Ortlepp, T.

    2017-02-01

    High power LEDs have conquered the mass market in recent years. Besides the main development focus to achieve higher productivity in the field of visible semiconductor LED processing, the wavelength range is further enhanced by active research and development in the direction of UVA / UVB / UVC. UVB and UVC LEDs are new and promising due to their numerous advantages. UV LEDs emit in a near range of one single emission peak with a width (FWHM) below 15 nm compared to conventional mercury discharge lamps and xenon sources, which show broad spectrums with many emission peaks over a wide range of wavelengths. Furthermore, the UV LED size is in the range of a few hundred microns and offers a high potential of significant system miniaturization. Of course, LED efficiency, lifetime and output power have to be increased [1]. Lifetime limiting issues of UVB/UVC-LED are the very high thermal stress in the chip resulting from the higher forward voltages (6-10 V @ 350 mA), the lower external quantum efficiency, below 10 % (most of the power disappears as heat), and the thermal resistance Rth of conventional LED packages being not able to dissipate these large amounts of heat for spreading. Beside the circuit boards and submounts which should have maximum thermal conductivity, the dimension of contacts as well as the interconnection of UV LED to the submount/package determinates the resolvable amount of heat [2]. In the paper different innovative interconnection techniques for UVC-LED systems will be discussed focused on the optimization of thermal conductivity in consideration of the assembly costs. Results on thermal simulation for the optimal contact dimensions and interconnections will be given. In addition, these theoretical results will be compared with results on electrical characterization as well as IR investigations on real UV LED packages in order to give recommendations for optimal UV LED assembly.

  9. Kinetics and mechanism investigation on the destruction of oxytetracycline by UV-254 nm activation of persulfate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yiqing [Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756 (China); Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); He, Xuexiang [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Fu, Yongsheng [Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States)

    2016-03-15

    Highlights: • The most effective destruction of OTC by UV/PS was achieved at near neutral pH. • Deprotonated HOTC{sup −} had the highest second-order rate constant with SO{sub 4}·{sup −}. • Presence of HCO{sub 3}{sup −} or Cu{sup 2+} enhanced the removal of OTC in UV/PS system. • Total organic carbon was degraded slowly during the mineralization of OTC. • Studies on the degradation mechanism revealed four different reaction pathways. - Abstract: Oxytetracycline (OTC), an important broad-spectrum antibiotic, has been detected extensively in various environmental systems, which may have a detrimental impact on ecosystem and human health through the development of drug resistant bacteria and pathogens. In this study, the degradation of OTC was evaluated by UV-254 nm activated persulfate (PS). The observed UV fluence based pseudo first-order rate constant (k{sub obs}) was found to be the highest at near neutral pH conditions (pH 5.5–8.5). Presence of various natural water constituents had different effects on OTC degradation, with a significant enhancement in the presence of bicarbonate or Cu{sup 2+}. Limited elimination of total organic carbon (TOC) and PS was observed during the mineralization of OTC. Transformation byproducts in the presence and absence of hydroxyl radical scavenging agent tert-butanol (t-BuOH) were identified using ultra-high definition accurate-mass quadrupole time-of-flight liquid chromatography/mass spectrometer (LC-QTOF/MS). Potential OTC degradation mechanism was subsequently proposed revealing four different reaction pathways by SO{sub 4}·{sup −} reaction including hydroxylation (+16 Da), demethylation (−14 Da), decarbonylation (−28 Da) and dehydration (−18 Da). This study suggests that UV-254 nm/PS is a promising treatment technology for the control of water pollution caused by emerging contaminants such as OTC.

  10. Development of an online UV-visible microspectrophotometer for a macromolecular crystallography beamline.

    Science.gov (United States)

    Shimizu, Nobutaka; Shimizu, Tetsuya; Baba, Seiki; Hasegawa, Kazuya; Yamamoto, Masaki; Kumasaka, Takashi

    2013-11-01

    Measurement of the UV-visible absorption spectrum is a convenient technique for detecting chemical changes of proteins, and it is therefore useful to combine spectroscopy and diffraction studies. An online microspectrophotometer for the UV-visible region was developed and installed on the macromolecular crystallography beamline, BL38B1, at SPring-8. This spectrophotometer is equipped with a difference dispersive double monochromator, a mercury-xenon lamp as the light source, and a photomultiplier as the detector. The optical path is mostly constructed using mirrors, in order to obtain high brightness in the UV region, and the confocal optics are assembled using a cross-slit diaphragm like an iris to eliminate stray light. This system can measure optical densities up to a maximum of 4.0. To study the effect of radiation damage, preliminary measurements of glucose isomerase and thaumatin crystals were conducted in the UV region. Spectral changes dependent on X-ray dose were observed at around 280 nm, suggesting that structural changes involving Trp or Tyr residues occurred in the protein crystal. In the case of the thaumatin crystal, a broad peak around 400 nm was also generated after X-ray irradiation, suggesting the cleavage of a disulfide bond. Dose-dependent spectral changes were also observed in cryo-solutions alone, and these changes differed with the composition of the cryo-solution. These responses in the UV region are informative regarding the state of the sample; consequently, this device might be useful for X-ray crystallography.

  11. The formation of massive primordial stars in the presence of moderate UV backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Latif, M. A.; Schleicher, D. R. G.; Bovino, S. [Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Grassi, T. [Centre for Star and Planet Formation, Natural History Museum of Denmark, Øster Voldgade 5-7, DK-1350 Copenhagen (Denmark); Spaans, M., E-mail: mlatif@astro.physik.uni-goettingen.de [Kapteyn Astronomical Institute, University of Groningen, 9700-AV Groningen (Netherlands)

    2014-09-01

    Radiative feedback produced by stellar populations played a vital role in early structure formation. In particular, photons below the Lyman limit can escape the star-forming regions and produce a background ultraviolet (UV) flux, which consequently may influence the pristine halos far away from the radiation sources. These photons can quench the formation of molecular hydrogen by photodetachment of H{sup –}. In this study, we explore the impact of such UV radiation on fragmentation in massive primordial halos of a few times 10{sup 7} M {sub ☉}. To accomplish this goal, we perform high resolution cosmological simulations for two distinct halos and vary the strength of the impinging background UV field in units of J {sub 21} assuming a blackbody radiation spectrum with a characteristic temperature of T {sub rad} = 10{sup 4} K. We further make use of sink particles to follow the evolution for 10,000 yr after reaching the maximum refinement level. No vigorous fragmentation is observed in UV-illuminated halos while the accretion rate changes according to the thermal properties. Our findings show that a few 10{sup 2}-10{sup 4} solar mass protostars are formed when halos are irradiated by J {sub 21} = 10-500 at z > 10 and suggest a strong relation between the strength of the UV flux and mass of a protostar. This mode of star formation is quite different from minihalos, as higher accretion rates of about 0.01-0.1 M {sub ☉} yr{sup –1} are observed by the end of our simulations. The resulting massive stars are potential cradles for the formation of intermediate-mass black holes at earlier cosmic times and contribute to the formation of a global X-ray background.

  12. Kinetics and mechanism investigation on the destruction of oxytetracycline by UV-254 nm activation of persulfate

    International Nuclear Information System (INIS)

    Liu, Yiqing; He, Xuexiang; Fu, Yongsheng; Dionysiou, Dionysios D.

    2016-01-01

    Highlights: • The most effective destruction of OTC by UV/PS was achieved at near neutral pH. • Deprotonated HOTC"− had the highest second-order rate constant with SO_4·"−. • Presence of HCO_3"− or Cu"2"+ enhanced the removal of OTC in UV/PS system. • Total organic carbon was degraded slowly during the mineralization of OTC. • Studies on the degradation mechanism revealed four different reaction pathways. - Abstract: Oxytetracycline (OTC), an important broad-spectrum antibiotic, has been detected extensively in various environmental systems, which may have a detrimental impact on ecosystem and human health through the development of drug resistant bacteria and pathogens. In this study, the degradation of OTC was evaluated by UV-254 nm activated persulfate (PS). The observed UV fluence based pseudo first-order rate constant (k_o_b_s) was found to be the highest at near neutral pH conditions (pH 5.5–8.5). Presence of various natural water constituents had different effects on OTC degradation, with a significant enhancement in the presence of bicarbonate or Cu"2"+. Limited elimination of total organic carbon (TOC) and PS was observed during the mineralization of OTC. Transformation byproducts in the presence and absence of hydroxyl radical scavenging agent tert-butanol (t-BuOH) were identified using ultra-high definition accurate-mass quadrupole time-of-flight liquid chromatography/mass spectrometer (LC-QTOF/MS). Potential OTC degradation mechanism was subsequently proposed revealing four different reaction pathways by SO_4·"− reaction including hydroxylation (+16 Da), demethylation (−14 Da), decarbonylation (−28 Da) and dehydration (−18 Da). This study suggests that UV-254 nm/PS is a promising treatment technology for the control of water pollution caused by emerging contaminants such as OTC.

  13. Stoppage in Autism Spectrum Disorders

    DEFF Research Database (Denmark)

    Grønborg, Therese Koops; Hansen, Stefan Nygaard; Nielsen, Svend V

    2015-01-01

    of bias in sibling recurrence risk estimation. This study investigated whether stoppage occurs in Danish families with a firstborn child diagnosed with autism spectrum disorders, and if stoppage was differential. We found that stoppage occurs moderately in Danish families affected by autism spectrum...... disorders, and that stoppage is differential. However, differential stoppage is a minor source of estimation bias in Danish sibling recurrence risk studies of autism spectrum disorders....

  14. Optical design for CETUS: a wide-field 1.5m aperture UV payload being studied for a NASA probe class mission study

    Science.gov (United States)

    Woodruff, Robert; Robert Woodruff, Goddard Space Flight Center, Kendrick Optical Consulting

    2018-01-01

    We are developing a NASA Headquarters selected Probe-class mission concept called the Cosmic Evolution Through UV Spectroscopy (CETUS) mission, which includes a 1.5-m aperture diameter large field-of-view (FOV) telescope optimized for UV imaging, multi-object spectroscopy, and point-source spectroscopy. The optical system includes a Three Mirror Anastigmatic (TMA) telescope that simultaneously feeds three separate scientific instruments: the near-UV (NUV) Multi-Object Spectrograph (MOS) with a next-generation Micro-Shutter Array (MSA); the two-channel camera covering the far-UV (FUV) and NUV spectrum; and the point-source spectrograph covering the FUV and NUV region with selectable R~ 40,000 echelle modes and R~ 2,000 first order modes. The optical system includes fine guidance sensors, wavefront sensing, and spectral and flat-field in-flight calibration sources. This paper will describe the current optical design of CETUS.

  15. You, me and UV under the sun in South Africa

    CSIR Research Space (South Africa)

    Wright, C

    2009-01-01

    Full Text Available This article asks just how harmful are our solar UV rays? It explains what previous researches tell us about how much UV radiation our children are likely to receive and what are the health risks....

  16. Regression in autistic spectrum disorders.

    Science.gov (United States)

    Stefanatos, Gerry A

    2008-12-01

    A significant proportion of children diagnosed with Autistic Spectrum Disorder experience a developmental regression characterized by a loss of previously-acquired skills. This may involve a loss of speech or social responsitivity, but often entails both. This paper critically reviews the phenomena of regression in autistic spectrum disorders, highlighting the characteristics of regression, age of onset, temporal course, and long-term outcome. Important considerations for diagnosis are discussed and multiple etiological factors currently hypothesized to underlie the phenomenon are reviewed. It is argued that regressive autistic spectrum disorders can be conceptualized on a spectrum with other regressive disorders that may share common pathophysiological features. The implications of this viewpoint are discussed.

  17. Deep UV emitting scintillators for alpha and beta particle detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y. [Department of Physics and Astronomy, University of Georgia, Athens, GA 30606 (United States); Jia, D.D.; Lewis, L.A. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Feofilov, S.P. [A.F. Ioffe Physical-Technical Institute, St. Petersburg, 194021 (Russian Federation); Meltzer, R.S., E-mail: rmeltzer@physast.uga.ed [Department of Physics and Astronomy, University of Georgia, Athens, GA 30606 (United States)

    2011-03-21

    Several deep UV emitting scintillators, whose emission falls in the solar blind region of the spectrum (200-280 nm), are described and their scintillator properties are characterized. They include LaPO{sub 4}:Pr, YPO{sub 4}:Pr, YAlO{sub 3}:Pr, Pr(PO{sub 3}){sub 3}, YPO{sub 4}:Bi and ScPO{sub 4}. These materials would facilitate the detection of ionizing radiation in open areas, even during the daylight hours, and could be used to support large area surveys that monitor for the presence of ionization radiation due, for example, to system leaks or transfer contamination. These materials can be used in the form of powders, thin films or paints for radiation detection. They are characterized for both beta radiation using electron beams (2-35 keV) and {sup 137}Cs and alpha radiations using {sup 241}Am sources. Their absolute light yields are estimated and are compared to that of Y{sub 2}SiO{sub 5}:Ce. Their light yields decrease as a function of electron energy but at 10 keV they approach 8000 ph/MeV.

  18. Structure of DNA damaged by UV and psoralen

    International Nuclear Information System (INIS)

    Sung-hou Kim; Tomic, M.T.; Wemmer, D.E.; Pearlman, D.; Holbrook, S.

    1988-01-01

    The authors have used NMR methods to determine a three-dimensional model of an 8 base-pair DNA fragment cross-linked with psoralen. The duplex form of the self-complementary deoxyribonucleotide d-GGGTACCC, contains a psoralen cross-linkable site at the center of the duplex. The cross-link was formed by UV irradiation of a mixture of the purified DNA octamer and 4'-(aminomethyl)-4,5',8-trimethylpsoralen (AMT). Structural information was obtained using one and two-dimensional NMR techniques. Two-dimensional NOE experiments were used to assign the spectrum and estimate distances for many pairs of protons in the cross-linked DNA. Structural parameters obtained are qualitatively consistent with a previously proposed model for kinked and unwound cross-linked B-form DNA derived from crystallography and molecular modeling. The NMR derived model has a 53 degree bend into the major groove occuring primarily at the site of drug addition, and a 56 degree unwinding spanning the 8 base pair duplex. (author)

  19. The production of UV Absorber amorphous cerium sulfide thin film

    Energy Technology Data Exchange (ETDEWEB)

    Kariper, İshak Afşin, E-mail: akariper@gmail.com [Faculty of Education, Erciyes University, Kayseri (Turkey)

    2017-10-15

    This study investigates the production of cerium sulfide (CeSx) amorphous thin films on substrates (commercial glass) by chemical bath deposition at different pH levels. The transmittance, absorption, optical band gap and refractive index of the films are measured by UV/VIS Spectrum. According to XRD analysis, the films show amorphous structure in the baths with pH: 1 to 5. It has been observed that the optical and structural properties of the films depend on pH value of the bath. The optical band gap (2.08 eV to 3.16 eV) of the films changes with the film thickness (23 nm to 1144 nm). We show that the refractive index has a positive relationship with the film thickness, where the values of 1.93, 1.45, 1.42, 2.60 and 1.39 are obtained for the former, and 34, 560, 509, 23 and 1144 nm (at 550 nm wavelength) for the latter. We compare the optical properties of amorphous and crystal form of CeSx thin films. We show that the optical band gaps of the amorphous CeS{sub x} are lower than that of crystal CeS{sub x} . (author)

  20. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Science.gov (United States)

    Zempila, Melina-Maria; van Geffen, Jos H. G. M.; Taylor, Michael; Fountoulakis, Ilias; Koukouli, Maria-Elissavet; van Weele, Michiel; van der A, Ronald J.; Bais, Alkiviadis; Meleti, Charikleia; Balis, Dimitrios

    2017-06-01

    This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS

  1. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    M.-M. Zempila

    2017-06-01

    Full Text Available This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4 UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh, in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990 and with a very low bias (0.000 to 0.011 in absolute units proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5

  2. Comparative investigation of X-ray contrast medium degradation by UV/chlorine and UV/H2O2.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Pang, Suyan

    2018-02-01

    The degradation of iopamidol and diatrizoate sodium (DTZ) by UV/chlorine was carried out according to efficiency, mechanism, and oxidation products, and compared to that by UV/H 2 O 2 . The pseudo-first order rate (k') of iopamidol and DTZ was accelerated by UV/chlorine compared to that by UV and chlorine alone. k' of iopamidol and DTZ by UV/chlorine increased with increasing chlorine dosage. Both of iopamidol and DTZ could not be effectively removed by UV/H 2 O 2 compared to that by UV/chlorine. Secondary radicals (Cl 2 - and ClO) rather than primary radicals (HO and Cl) were demonstrated to be mainly responsible for the enhanced removal of iopamidol and DTZ by UV/chlorine. The oxidation products of iopamidol and DTZ resulting from UV/chlorine and UV/H 2 O 2 process were identified, and differences existed in the two systems. IO 3 - (the desired sink of I - ) was the major inorganic product in the UV/chlorine process whereas I - was the predominant inorganic product in the UV/H 2 O 2 process. The formation of chlorine-containing products during the degradation of iopamidol and DTZ by UV/chlorine was also observed. H-abstraction, additions, de-iodination were shared during the degradation of iopamidol by UV/chlorine and UV/H 2 O 2 . Neutral pH condition was preferred for the removal of iopamidol and DTZ by UV/chlorine. UV/chlorine could also be applied in real waters for the removal of iopamidol and DTZ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Prediction of UV spectra and UV-radiation damage in actual plasma etching processes using on-wafer monitoring technique

    International Nuclear Information System (INIS)

    Jinnai, Butsurin; Fukuda, Seiichi; Ohtake, Hiroto; Samukawa, Seiji

    2010-01-01

    UV radiation during plasma processing affects the surface of materials. Nevertheless, the interaction of UV photons with surface is not clearly understood because of the difficulty in monitoring photons during plasma processing. For this purpose, we have previously proposed an on-wafer monitoring technique for UV photons. For this study, using the combination of this on-wafer monitoring technique and a neural network, we established a relationship between the data obtained from the on-wafer monitoring technique and UV spectra. Also, we obtained absolute intensities of UV radiation by calibrating arbitrary units of UV intensity with a 126 nm excimer lamp. As a result, UV spectra and their absolute intensities could be predicted with the on-wafer monitoring. Furthermore, we developed a prediction system with the on-wafer monitoring technique to simulate UV-radiation damage in dielectric films during plasma etching. UV-induced damage in SiOC films was predicted in this study. Our prediction results of damage in SiOC films shows that UV spectra and their absolute intensities are the key cause of damage in SiOC films. In addition, UV-radiation damage in SiOC films strongly depends on the geometry of the etching structure. The on-wafer monitoring technique should be useful in understanding the interaction of UV radiation with surface and in optimizing plasma processing by controlling UV radiation.

  4. Action Spectrum of Photoinhibition in the Diatom Phaeodactylum tricornutum.

    Science.gov (United States)

    Havurinne, Vesa; Tyystjärvi, Esa

    2017-12-01

    Light-dependent electron transfer is necessary for photosynthesis, but light also damages PSII. Light-induced damage to PSII is called photoinhibition, and the damaging reactions of photoinhibition are still under debate. Diatoms possess an exotic combination of light-harvesting pigments, Chls a/c and fucoxanthin, making them an interesting platform for studying the photoreceptors of photoinhibition. We first confirmed the direct proportionality of photoinhibition to the photon flux density of incident light in the diatom Phaeodactylum tricornutum. Phaeodactylum is known for its efficient non-photochemical quenching, and the effect of this photoprotective mechanism on photoinhibition was tested. Photoinhibition proceeded essentially at the same rate in blue-light-grown Phaeodactylum cells that are capable of non-photochemical quenching and in red-light-grown, non-photochemical quenching-deficient cells. To obtain more insight into how the pigment composition of diatoms affects photoinhibition, we measured the action spectrum of photoinhibition in Phaeodactylum. In visible light, the action spectrum resembled the absorption spectrum of Phaeodactylum, and UV radiation caused much more photoinhibition than visible light. Comparison of the action spectrum of photoinhibition with the absorption spectrum and the excitation spectrum of 77 K PSII fluorescence emission confirmed that photosynthetic pigments are involved in photoinhibition, but the photoinhibitory efficiency of red light is weak, suggesting that the role of light-harvesting pigments as light receptors of photoinhibition is secondary. Finally, we compared photoinhibition in Phaeodactylum with that in other photosynthetic organisms, and our data indicate that the PSII reaction centers of Phaeodactylum are not particularly well protected against the primary damage of photoinhibition. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights

  5. The global and UV-B radiation over Egypt

    OpenAIRE

    BASSET, H. A.; KORANY, M. H.

    2007-01-01

    This work studies the relation between UV-B radiation and global radiation over Egypt. The relationships between the global solar radiation and UV-B radiation at four stations in Egypt have been studied, and linear empirical formulas for estimating UV-B from global radiation at these stations has been deduced. The deduced equations were applied to calculate the UV-B radiation for other stations where measurements were unavailable, using records of global radiation at these stations. Because o...

  6. Improving UV Resistance of High Performance Fibers

    Science.gov (United States)

    Hassanin, Ahmed

    High performance fibers are characterized by their superior properties compared to the traditional textile fibers. High strength fibers have high modules, high strength to weight ratio, high chemical resistance, and usually high temperature resistance. It is used in application where superior properties are needed such as bulletproof vests, ropes and cables, cut resistant products, load tendons for giant scientific balloons, fishing rods, tennis racket strings, parachute cords, adhesives and sealants, protective apparel and tire cords. Unfortunately, Ultraviolet (UV) radiation causes serious degradation to the most of high performance fibers. UV lights, either natural or artificial, cause organic compounds to decompose and degrade, because the energy of the photons of UV light is high enough to break chemical bonds causing chain scission. This work is aiming at achieving maximum protection of high performance fibers using sheathing approaches. The sheaths proposed are of lightweight to maintain the advantage of the high performance fiber that is the high strength to weight ratio. This study involves developing three different types of sheathing. The product of interest that need be protected from UV is braid from PBO. First approach is extruding a sheath from Low Density Polyethylene (LDPE) loaded with different rutile TiO2 % nanoparticles around the braid from the PBO. The results of this approach showed that LDPE sheath loaded with 10% TiO2 by weight achieved the highest protection compare to 0% and 5% TiO2. The protection here is judged by strength loss of PBO. This trend noticed in different weathering environments, where the sheathed samples were exposed to UV-VIS radiations in different weatheromter equipments as well as exposure to high altitude environment using NASA BRDL balloon. The second approach is focusing in developing a protective porous membrane from polyurethane loaded with rutile TiO2 nanoparticles. Membrane from polyurethane loaded with 4

  7. UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

    Directory of Open Access Journals (Sweden)

    Alyaa M. Zyara

    2017-01-01

    Full Text Available UV-LEDs are a new method of disinfecting drinking water. Some viruses are very resistant to UV and the efficiency of UV-LEDs to disinfect them needs to be studied. Drinking water was disinfected with UV-LEDs after spiking the water with MS2 and four UV- and/or Cl-resistant coliphages belonging to RNA or DNA coliphages isolated from municipal wastewater. UV-LEDs operating at a wavelength of 270 nm for 2 min with 120 mW of irradiation caused 0.93–2.73 Log10-reductions of coliphages tested in a reactor of a 5.2 L volume. Irradiation time of 10 min in the same system increased the Log10-reductions to 4.30–5.16. Traditional mercury UV (Hg-UV lamp at a 254 nm wavelength caused 0.67–4.08 Log10-reductions in 2 min and 4.56–7.21 Log10-reductions in 10 min in 10 mL of water. All coliphages tested except MS2 achieved 4 Log10-reductions with UV-LEDs at a dose that corresponded to 70 mWs/cm2 using Hg-UV. Thus, UV-LEDs are a promising method of disinfecting UV- and/or Cl-resistant viruses.

  8. Increased resistance of environmental anaerobic spores to inactivation by UV

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Veer, A.J. van der; Beerendonk, E.F.; Medema, Gerriet Jan

    2004-01-01

    Water Company Europoort started a pilot plant (MP)UV study to determine the UV-fluence to meet the Dutch drinking water standards. The results of large volume sampling of this pilot plant demonstrated that environmental spores of sulphite-reducing clostridia (SSRC) were highly resistant against UV.

  9. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  10. People with Increased Risk of Eye Damage from UV Light

    Science.gov (United States)

    ... With Increased Risk of Eye Damage from UV Light Leer en Español: Algunas Personas Están en Mayor Riesgo de Sufrir Daño Ocular por los Rayos UV Written By: Shirley Dang Apr. 30, 2014 Everyone of any age and any degree of skin pigmentation is susceptible to UV damage. Children are ...

  11. Mutagenesis at the ad-3A and ad-3B loci in haploid UV-sensitive strains of Neurospora crassa. Pt. 6

    International Nuclear Information System (INIS)

    De Serres, F.J.; Inoue, H.; Schuepbach, M.E.

    1983-01-01

    Genetic characterization of ad-3B mutants induced in wild-type and UV-sensitive strains has revealed qualitative differences between the spectra of genetic alterations at the molecular level. Ad-3B mutants induced in the two nucleotide excision-repair-deficient strains upr-1 and uvs-2 had significantly lower frequencies of nonpolarized complementation patterns and higher frequencies of noncomplementing mutants than ad-3B mutants induced in the wild-type strain in samples induced by either UV, #betta#-rays, 4NQO or MNNG. In these same samples ad-3B mutants induced in uvs-4, uvs-5 or uvs-6 did not differ significantly from those induced in the wild-type strain. After ICR-170 treatment, ad-3B mutants induced in the UV-sensitive strains did not differ significantly from those induced in wild-type. The comparisons in the present and previous studies demonstrate that the process of mutation-induction in the ad-3 region is under the control of other loci that not only alter mutant recovery quantitatively but also qualitatively. These data have important implications for comparative chemical mutagenesis, since the spectrum of genetic alterations produced by a given agent can be modified markedly as a result of defects in DNA repair. (orig./AJ)

  12. Reactivation of UV- and γ-irradiated herpes virus in UV- and X-irradiated CV-1 cells

    International Nuclear Information System (INIS)

    Takimoto, K.; Niwa, O.; Sugahara, T.

    1982-01-01

    Enhanced reactivation of UV- and γ-irradiated herpes virus was investigated by the plaque assay on CV-1 monkey kidney monolayer cells irradiated with UV light or X-rays. Both UV- and X-irradiated CV-1 cells showed enhancement of survival of UV-irradiated virus, while little or no enhancement was detected for γ-irradiated virus assayed on UV- or X-irradiated cells. The enhanced reactivation of UV-irradiated virus was greater when virus infection was delayed 24 or 48 h, than for infection immediately following the irradiation of cells. Thus the UV- or X-irradiated CV-1 cells are able to enhance the repair of UV damaged herpes virus DNA, but not of γ-ray damaged ones. (author)

  13. Immunogenicity of UV-inactivated measles virus

    International Nuclear Information System (INIS)

    Zahorska, R.; Mazur, N.; Korbecki, M.

    1978-01-01

    By means of the antigen extinction limit test it was shown that a triple dose vaccination of guinea pigs with UV-inactivated measles virus gave better results, than a single dose vaccination which was proved by the very low immunogenicity index. For both vaccination schemes (single and triple) the immune response was only sligthly influenced by a change of dose from 10 5 to 10 6 HadU 50 /ml or by the addition of aluminum adjuvant. In the antigen extinction limit test the antibody levels were determined by two methods (HIT and NT) the results of which were statistically equivalent. The UV-inactivated measles virus was also found to induce hemolysis-inhibiting antibodies. (orig.) [de

  14. Effect of UV-irradiation on rotavirus

    International Nuclear Information System (INIS)

    Smirnov, Y.A.; Kapitulets, S.P.; Kaverin, N.V.; Amitina, N.N.; Ginevskaya, V.A.

    1991-01-01

    The effect of UV-irradiation on the infectivity of the SAll rotavirus was examined. The time behavior of the inactivation of infectivity generally exhibited the one-hit pattern. The effect was studied with respect to two phenomena, viz. the RNA-protein linkage and the formation of uracil dimers. To determine the number of the latter, purified 3 H-uridine-labelled rotavirus was exposed to UV radiation, and the RNA was extracted and analyzed by paper chromatography in the ascending mode. The formation of photodimers was found to be an important mechanism in the rotavirus inactivation on conventional irradiation, whereas RNA-protein linkages were observed on the application of high doses only. (author). 3 figs., 10 refs

  15. UV inactivation of pathogenic and indicator microorganisms

    International Nuclear Information System (INIS)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-01-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts

  16. UV inactivation of pathogenic and indicator microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J.C.; Ossoff, S.F.; Lobe, D.C.; Dorfman, M.H.; Dumais, C.M.; Qualls, R.G.; Johnson, J.D.

    1985-06-01

    Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.

  17. The optimal UV exposure time for vitamin D3 synthesis and erythema estimated by UV observations in Korea

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2016-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) from spectral UV measurements during 2006-2010. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied to the broadband UV measured by UV-Biometer at 6 sites in Korea Thus, the optimal UV exposure time for vitamin D3 synthesis and erythema was estimated for diurnal, seasonal, and annual scales over Korea. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice

  18. Cycloaliphatic epoxide resins for cationic UV - cure

    International Nuclear Information System (INIS)

    Verschueren, K.; Balwant Kaur

    1999-01-01

    This paper introduces the cyclo - aliphatic epoxide resins used for the various applications of radiation curing and their comparison with acrylate chemistry. Radiation curable coatings and inks are pre - dominantly based on acrylate chemistry but over the last few years, cationic chemistry has emerged successfully with the unique properties inherent with cyclo - aliphatic epoxide ring structures. Wide variety of cationic resins and diluents, the formulation techniques to achieve the desired properties greatly contributes to the advancement of UV - curing technology

  19. Mechanisms underlying UV-induced immune suppression

    International Nuclear Information System (INIS)

    Ullrich, Stephen E.

    2005-01-01

    Skin cancer is the most prevalent form of human neoplasia. Estimates suggest that in excess of one million new cases of skin cancer will be diagnosed this year alone in the United States (www.cancer.org/statistics). Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer. The cost of treating non-melanoma skin cancer is estimated to be in excess of US$ 650 million a year [J.G. Chen, A.B. Fleischer, E.D. Smith, C. Kancler, N.D. Goldman, P.M. Williford, S.R. Feldman, Cost of non-melanoma skin cancer treatment in the United States, Dermatol. Surg. 27 (2001) 1035-1038], and when melanoma is included, the estimated cost of treating skin cancer in the United States is estimated to rise to US$ 2.9 billion annually (www.cancer.org/statistics). Because the morbidity and mortality associated with skin cancer is a major public health problem, it is important to understand the mechanisms underlying skin cancer development. The primary cause of skin cancer is the ultraviolet (UV) radiation found in sunlight. In addition to its carcinogenic potential, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. The focus of this manuscript will be to review the mechanisms underlying the induction of immune suppression following UV exposure. Particular attention will be directed to the role of soluble mediators in activating immune suppression

  20. Key factors for UV curable pigment dispersions

    International Nuclear Information System (INIS)

    Magny, B.; Pezron, E.; Ciceron, P.H.; Askienazy, A.

    1999-01-01

    UV oligomers with good pigment dispersion are needed to allow good formulation flexibility and possibility to apply thinner films. Pigment dispersion mainly depends on three phenomena: the wetting of agglomerates, the breakage of agglomerates by mechanical stress and the stabilization of smaller agglomerates and primary particles against flocculation. It has been shown that oligomers with low viscosity and low surface tension induce a good pigment wetting. Examples of monomers and oligomers for good pigment dispersion are given