Science.gov

Sample records for 6-4 pyrimidone photoproducts

  1. DNA photochemistry: geometrically unconstrained pyrimidine (6-4) pyrimidone photoproducts do photoisomerize.

    PubMed

    Douki, Thierry; Rebelo-Moreira, Silvestre; Hamon, Nadège; Bayle, Pierre-Alain

    2015-01-16

    Structural features are of major importance for the formation of mutagenic photoproducts in DNA. It was recently reported that lack of constraints between two adjacent nucleosidic units prevents the conversion of pyrimidine (6-4) pyrimidone photoproducts into their Dewar valence isomers. We here report that this is not the case for the thymidine photoproducts which, although unconstrained, are quantitatively converted into photolysis products identified as Dewar valence isomers by mass spectrometry and NMR and infrared spectroscopies.

  2. An Unexpected Deamination Reaction after Hydrolysis of the Pyrimidine (6-4) Pyrimidone Photoproduct

    PubMed Central

    2015-01-01

    Pyrimidine (6-4) pyrimidone photoproduct (6-4PP), a common DNA photolesion formed under solar irradiation, was indicated to hydrolyze under strong basic conditions, breaking the N3–C4 bond at the 5′-thymine. The reanalysis of this reaction revealed that the resulting water adduct may not be stable as previously proposed; it readily undergoes an esterification reaction induced by the 5-OH group at 6-4PP to form a five-membered ring, eliminating a molecule of ammonia. PMID:25250878

  3. Inhibition of RNA and DNA synthesis in UV-irradiated normal human fibroblasts is correlated with pyrimidine (6-4) pyrimidone photoproduct formation.

    PubMed

    Petit Frère, C; Clingen, P H; Arlett, C F; Green, M H

    1996-07-05

    UV-irradiation of living cells results in an inhibition of RNA and DNA synthesis. The purpose of this study was to determine whether specific photoproducts or the total combined yield of lesions were responsible for these effects. Asynchronously dividing human fibroblasts from normal donors were irradiated with UVC (254 nm), broad spectrum UVB (290-320 + nm, Westinghouse FS20 lamp) or narrow spectrum UVB (310-315 nm, Philips TL01 lamp) at fluences which induce known yields of cyclobutane pyrimidine dimers, pyrimidine (6-4) pyrimidone photoproducts or Dewar isomers. DNA synthesis was approximately 3-4 times more sensitive to both UVC and UVB irradiation than RNA synthesis. The immediate inhibition of RNA and DNA synthesis was correlated with (6-4) rather than overall photoproduct formation suggesting that the (6-4) photoproduct is the mediator of these inhibitory effects. In support of this suggestion we found that photoreactivation of cells cultured from the marsupial, mouse Sminthopsis crassicaudata, resulted in removal of 70% of pyrimidine dimers from the overall genome, but had only a slight effect on the recovery of RNA synthesis.

  4. Cloning and characterization of a gene (UVR3) required for photorepair of 6-4 photoproducts in Arabidopsis thaliana.

    PubMed Central

    Nakajima, S; Sugiyama, M; Iwai, S; Hitomi, K; Otoshi, E; Kim, S T; Jiang, C Z; Todo, T; Britt, A B; Yamamoto, K

    1998-01-01

    UV radiation induces two major classes of pyrimidine dimers: the pyrimidine [6-4] pyrimidone photoproduct (6-4 product) and the cyclobutane pyrimidine dimer (CPD). Many organisms produce enzymes, termed photolyases, that specifically bind to these damage products and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. A gene that expresses a protein with 6-4 photolyase activity in vitro was recently cloned from Drosophila melanogaster and Xenopus laevis. We report here the isolation of a homolog of this gene, cloned on the basis of sequence similarity, from the higher plant Arabidopsis thaliana. This cloned gene produces a protein with 6-4 photolyase activity when expressed in Escherichia coli. We also find that a previously described mutant of Arabidopsis (uvr3) that is defective in photoreactivation of 6-4 products carries a nonsense mutation in this 6-4 photolyase homolog. We have therefore termed this gene UVR3. Although homologs of this gene have previously been shown to produce a functional 6-4 photolyase when expressed in heterologous systems, this is the first demonstration of a requirement for this gene for photoreactivation of 6-4 products in vivo. PMID:9421527

  5. DNA sequence context greatly affects the accuracy of bypass across an ultraviolet light 6-4 photoproduct in mammalian cells.

    PubMed

    Shriber, Pola; Leitner-Dagan, Yael; Geacintov, Nicholas; Paz-Elizur, Tamar; Livneh, Zvi

    2015-10-01

    Translesion DNA synthesis (TLS) is a DNA damage tolerance mechanism carried out by low-fidelity DNA polymerases that bypass DNA lesions, which overcomes replication stalling. Despite the miscoding nature of most common DNA lesions, several of them are bypassed in mammalian cells in a relatively accurate manner, which plays a key role maintaining a low mutation load. Whereas it is generally agreed that TLS across the major UV and sunlight induced DNA lesion, the cyclobutane pyrimidine dimer (CPD), is accurate, there were conflicting reports on whether the same is true for the thymine-thymine pyrimidine-pyrimidone(6-4) ultraviolet light photoproduct (TT6-4PP), which represents the second most common class of UV lesions. Using a TLS assay system based on gapped plasmids carrying site-specific TT6-4PP lesions in defined sequence contexts we show that the DNA sequence context markedly affected both the extent and accuracy of TLS. The sequence exhibiting higher TLS exhibited also higher error-frequency, caused primarily by semi-targeted mutations, at the nearest nucleotides flanking the lesion. Our results resolve the discrepancy reported on TLS across TT6-4PP, and suggest that TLS is more accurate in human cells than in mouse cells.

  6. Mechanism of the alkali degradation of (6-4) photoproduct-containing DNA.

    PubMed

    Arichi, Norihito; Inase, Aki; Eto, Sachise; Mizukoshi, Toshimi; Yamamoto, Junpei; Iwai, Shigenori

    2012-03-21

    The (6-4) photoproduct is one of the major damaged bases produced by ultraviolet light in DNA. This lesion is known to be alkali-labile, and strand breaks occur at its sites when UV-irradiated DNA is treated with hot alkali. We have analyzed the product obtained by the alkali treatment of a dinucleoside monophosphate containing the (6-4) photoproduct, by HPLC, NMR spectroscopy, and mass spectrometry. We previously found that the N3-C4 bond of the 5' component was hydrolyzed by a mild alkali treatment, and the present study revealed that the following reaction was the hydrolysis of the glycosidic bond at the 3' component. The sugar moiety of this component was lost, even when a 3'-flanking nucleotide was not present. Glycosidic bond hydrolysis was also observed for a dimer and a trimer containing 5-methyl-2-pyrimidinone, which was used as an analog of the 3' component of the (6-4) photoproduct, and its mechanism was elucidated. Finally, the alkali treatment of a tetramer, d(GT(6-4)TC), yielded 2'-deoxycytidine 5'-monophosphate, while 2'-deoxyguanosine 3'-monophosphate was not detected. This result demonstrated the hydrolysis of the glycosidic bond at the 3' component of the (6-4) photoproduct and the subsequent strand break by β-elimination. It was also shown that the glycosidic bond at the 3' component of the Dewar valence isomer was more alkali-labile than that of the (6-4) photoproduct.

  7. Photoproduct frequency is not the major determinant of UV base substitution hot spots or cold spots in human cells

    SciTech Connect

    Brash, D.E.; Seetharam, S.; Kraemer, K.H.; Seidman, M.M.; Bredberg, A.

    1987-06-01

    The role of UV radiation-induced photoproducts in initiating base substitution mutations in human cells was examined by measuring photoproduct frequency distributions and mutations in a supF tRNA gene on a shuttle vector plasmid transfected into DNA repair-deficient cells (xeroderma pigmentosum, complementation group A) and into normal cells. Frequencies of cyclobutane dimers and pyrimidine-pyrimidone (6-4) photoproducts varied by as much as 80-fold at different dipyrimidine sites within the gene. All transition mutations occurred at dipyrimidine sites, predominantly at cytosine, with a 17-fold variation in mutation frequency between different sites. Removal of greater than 99% of the cyclobutane dimers by in vitro photoreactivation before transfection reduced the mutation frequency while preserving the mutation distribution, indicating that (i) cytosine-containing cyclobutane dimers were the major mutagenic lesions at these sites and (ii) cytosine-containing non-cyclobutane dimer photoproducts were also mutagenic lesions. However, at individual dipyrimidine sites neither the frequency of cyclobutane dimers nor the frequency of pyrimidine-pyrimidone (6-4) photoproducts correlated with the mutation frequency, even in the absence of excision repair. Mutation hot spots occurred at sites with low or high frequency of photoproduct formation and mutation cold spots occurred at sites with many photoproducts. These results suggest that although photoproducts are required for UV mutagenesis, the prominence of most mutation hot spots and cold spots is primarily determined by DNA structural features rather than by the frequency of DNA photoproducts.

  8. Repair of 254 nm ultraviolet-induced (6-4) photoproducts: monoclonal antibody recognition and differential defects in xeroderma pigmentosum complementation groups A, D, and variant

    SciTech Connect

    Hiramoto, T.; Matsunaga, T.; Ichihashi, M.; Nikaido, O.; Fujiwara, Y.; Mishima, Y. )

    1989-11-01

    Repair kinetics of ultraviolet (UV) light-induced (6-4) photoproducts in xeroderma pigmentosum complementation group A, D, and variant cells were studied by the enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody raised against (6-4) photoproducts, together with unscheduled DNA synthesis (UDS) and loss of T4 endonuclease V-susceptible sites (ESS). Group AXP35KO cells completely failed to repair both ESS (cyclobutane pyrimidine dimers) and antibody-recognizing (6-4) photoproducts until tested 24 h after irradiation, and had 2% early-time UDS. Group DXP43KO cells showed about 10% removal of both (6-4) photoproducts and ESS in 24 h, despite showing a residually higher level of 40% early-time and cumulative UDS. Thus, the results substantiated the extreme UV hypersensitivity of XP group A and D cells. However, XP52KO variant cells exhibited the normal level of UDS and ESS loss, but a slightly reduced repair of antibody-recognizing (6-4) photoproducts at 6 and 12 h after irradiation, which may account for a small UV hypersensitivity of the XP variant cells.

  9. Flavin adenine dinucleotide as a chromophore of the Xenopus (6-4)photolyase.

    PubMed Central

    Todo, T; Kim, S T; Hitomi, K; Otoshi, E; Inui, T; Morioka, H; Kobayashi, H; Ohtsuka, E; Toh, H; Ikenaga, M

    1997-01-01

    Two types of enzyme utilizing light from the blue and near-UV spectral range (320-520 nm) are known to have related primary structures: DNA photolyase, which repairs UV-induced DNA damage in a light-dependent manner, and the blue light photoreceptor of plants, which mediates light-dependent regulation of seedling development. Cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts [(6-4)photoproducts] are the two major photoproducts produced in DNA by UV irradiation. Two types of photolyases have been identified, one specific for CPDs (CPD photolyase) and another specific for (6-4)photoproducts [(6-4)photolyase]. (6-4)Photolyase activity was first found in Drosophila melanogaster and to date this gene has been cloned only from this organism. The deduced amino acid sequence of the cloned gene shows that (6-4)photolyase is a member of the CPD photolyase/blue light photoreceptor family. Both CPD photolyase and blue light photoreceptor are flavoproteins and bound flavin adenine dinucleotides (FADs) are essential for their catalytic activity. Here we report isolation of a Xenopus laevis(6-4)photolyase gene and show that the (6-4)photolyase binds non- covalently to stoichiometric amounts of FAD. This is the first indication of FAD as the chromophore of (6-4)photolyase. PMID:9016626

  10. Strand breakage of a (6-4) photoproduct-containing DNA at neutral pH and its repair by the ERCC1-XPF protein complex.

    PubMed

    Arichi, Norihito; Yamamoto, Junpei; Takahata, Chiaki; Sano, Emi; Masuda, Yuji; Kuraoka, Isao; Iwai, Shigenori

    2013-06-07

    The (6-4) photoproduct is one of the major UV-induced lesions in DNA. We previously showed that hydrolytic ring opening of the 5' base and subsequent hydrolysis of the glycosidic bond of the 3' component occurred when this photoproduct was treated with aqueous NaOH. In this study, we found that another product was obtained when the (6-4) photoproduct was heated at 90 °C for 6 h, in a 0.1 M solution of N,N'-dimethyl-1,2-ethanediamine adjusted to pH 7.4 with acetic acid. An analysis of the chemical structure of this product revealed that the 5' base was intact, whereas the glycosidic bond at the 3' component was hydrolyzed in the same manner. The strand break was detected for a 30-mer oligonucleotide containing the (6-4) photoproduct upon treatment with the above solution or other pH 7.4 solutions containing biogenic amines, such as spermidine and spermine. In the case of spermidine, the rate constant was calculated to be 1.4 × 10(-8) s(-1) at 37 °C. The strand break occurred even when the oligonucleotide was heated at 90 °C in 0.1 M sodium phosphate (pH 7.0), although this treatment produced several types of 5' fragments. The Dewar valence isomer was inert to this reaction. The product obtained from the (6-4) photoproduct-containing 30-mer was used to investigate the enzymatic processing of the 3' end bearing the damaged base and a phosphate. The ERCC1-XPF complex removed several nucleotides containing the damaged base, in the presence of replication protein A.

  11. Formation of cyclobutane dimers and (6-4) photoproducts upon far-UV photolysis of 5-methylcytosine-containing dinucleotide monophosphates.

    PubMed

    Douki, T; Cadet, J

    1994-10-04

    The far-UV photochemistry of 5-methylcytosine, a minor DNA base, was studied in three dinucleoside monophosphates, including m5dCpT, Tpm5dC, and m5dCpdC. The model compounds were exposed to 254-nm radiation, and the resulting photoproducts were isolated by reverse-phase HPLC and characterized as cyclobutane dimers, (6-4) adducts, and the related Dewar valence isomers by UV, mass, and 1H NMR spectroscopies. The rate of formation of the different photoproducts was compared with those obtained by photolysis of TpT and the corresponding cytosine dinucleoside monophosphates, including dCpT, TpdC, and dCpdC. The formation of deaminated m5dC-containing photoproducts was observed in each of the far-UV irradiated solution of m5dCpT, Tpm5dC, and m5dCpdC. They were shown to be generated mainly through a photochemical process since methylation of the C5 atom of the cytosine ring appeared to dramatically decrease the deamination rate of the C5-C6 saturated photoproducts.

  12. Fully functional global genome repair of (6-4) photoproducts and compromised transcription-coupled repair of cyclobutane pyrimidine dimers in condensed mitotic chromatin

    SciTech Connect

    Komura, Jun-ichiro; Ikehata, Hironobu; Mori, Toshio; Ono, Tetsuya

    2012-03-10

    During mitosis, chromatin is highly condensed, and activities such as transcription and semiconservative replication do not occur. Consequently, the condensed condition of mitotic chromatin is assumed to inhibit DNA metabolism by impeding the access of DNA-transacting proteins. However, about 40 years ago, several researchers observed unscheduled DNA synthesis in UV-irradiated mitotic chromosomes, suggesting the presence of excision repair. We re-examined this subject by directly measuring the removal of UV-induced DNA lesions by an ELISA and by a Southern-based technique in HeLa cells arrested at mitosis. We observed that the removal of (6-4) photoproducts from the overall genome in mitotic cells was as efficient as in interphase cells. This suggests that global genome repair of (6-4) photoproducts is fully functional during mitosis, and that the DNA in mitotic chromatin is accessible to proteins involved in this mode of DNA repair. Nevertheless, not all modes of DNA repair seem fully functional during mitosis. We also observed that the removal of cyclobutane pyrimidine dimers from the dihydrofolate reductase and c-MYC genes in mitotic cells was very slow. This suggests that transcription-coupled repair of cyclobutane pyrimidine dimers is compromised or non-functional during mitosis, which is probably the consequence of mitotic transcriptional repression. -- Highlights: Black-Right-Pointing-Pointer Global genome repair of (6-4) photoproducts is fully active in mitotic cells. Black-Right-Pointing-Pointer DNA in condensed mitotic chromatin does not seem inaccessible or inert. Black-Right-Pointing-Pointer Mitotic transcriptional repression may impair transcription-coupled repair.

  13. Fully functional global genome repair of (6-4) photoproducts and compromised transcription-coupled repair of cyclobutane pyrimidine dimers in condensed mitotic chromatin.

    PubMed

    Komura, Jun-ichiro; Ikehata, Hironobu; Mori, Toshio; Ono, Tetsuya

    2012-03-10

    During mitosis, chromatin is highly condensed, and activities such as transcription and semiconservative replication do not occur. Consequently, the condensed condition of mitotic chromatin is assumed to inhibit DNA metabolism by impeding the access of DNA-transacting proteins. However, about 40 years ago, several researchers observed unscheduled DNA synthesis in UV-irradiated mitotic chromosomes, suggesting the presence of excision repair. We re-examined this subject by directly measuring the removal of UV-induced DNA lesions by an ELISA and by a Southern-based technique in HeLa cells arrested at mitosis. We observed that the removal of (6-4) photoproducts from the overall genome in mitotic cells was as efficient as in interphase cells. This suggests that global genome repair of (6-4) photoproducts is fully functional during mitosis, and that the DNA in mitotic chromatin is accessible to proteins involved in this mode of DNA repair. Nevertheless, not all modes of DNA repair seem fully functional during mitosis. We also observed that the removal of cyclobutane pyrimidine dimers from the dihydrofolate reductase and c-MYC genes in mitotic cells was very slow. This suggests that transcription-coupled repair of cyclobutane pyrimidine dimers is compromised or non-functional during mitosis, which is probably the consequence of mitotic transcriptional repression.

  14. Immunological detection of UV induced cyclobutane pyrimidine dimers and (6-4) photoproducts in DNA from reference bacteria and natural aquatic populations.

    PubMed

    Kraft, Stephanie; Stephanie, Kraft; Obst, Ursula; Ursula, Obst; Schwartz, Thomas; Thomas, Schwartz

    2011-03-01

    UV light-caused DNA damage is a widespread field of study. As UV light has the biological effect of inactivating or killing bacteria, it is used for water disinfection. Due to this application, it is important to study the DNA damage efficiencies and regeneration capacities in bacteria after UV irradiation. Two monoclonal antibodies, anti-CPD and anti-(6-4) PP, were applied for an immunoassay of UV-induced DNA modifications. Cyclobutane pyrimidine dimer (CPD) and 6-4 photoproduct (6-4 PP) were detected in the reference bacteria Pseudomonas aeruginosa and Enterococcus faecium, and in natural water communities. The antibody-mediated detection signals increased with the UV doses from 100-400J/m(2). Here, the CPD-specific signals were stronger than the (6-4) PP-specific signals. These immunological results were in accordance with parallel cultivation experiments. All UV-irradiated bacteria showed a reduction of their growth rate depending on UV application by several orders of magnitudes. The immunoassay was also applied to three types of natural aquatic habitats with different cell densities. Besides artificial UV irradiation, it was possible to visualize natural sunlight effects on these natural bacterial communities. Light-dependent and dark repair processes were distinguished using the established immunological assays. The antibody-mediated analyses presented are fast methods to detect UV-induced DNA lesions and repair capacities in selected bacterial species as well as in entire natural mixed populations.

  15. Far-UV photochemistry and photosensitization of 2'-deoxycytidylyl-(3'-5')-thymidine: isolation and characterization of the main photoproducts.

    PubMed

    Douki, T; Cadet, J

    1992-08-31

    Far-UV irradiation of 2'-deoxycytidylyl-(3'-5')-thymidine (dCpT) gave rise to the pyrimidine (6-4) pyrimidone adduct and its Dewar valence isomer as the main photoproducts. The absolute configuration of the former adduct was determined and its photoisomerization studied. A comparison of the alkali lability of both compounds showed that hydrolysis of the phosphodiester bond occurs for the Dewar valence isomer but not for its (6-4) precursor. In addition, the trans-syn and cis-syn cyclobutane dimers of dCpT were obtained by acetophenone photosensitization and characterized. Finally, the deamination rate constants for this series of compounds were shown to be dramatically influenced by the nature and the configuration of the photoproducts.

  16. Resistance of the genome of Escherichia coli and Listeria monocytogenes to irradiation evaluated by the induction of cyclobutane pyrimidine dimers and 6-4 photoproducts using gamma and UV-C radiations

    NASA Astrophysics Data System (ADS)

    Beauchamp, S.; Lacroix, M.

    2012-08-01

    The effect of gamma and UV-C irradiation on the production of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4 PPs) in DNA was investigated to compare the natural resistance of the genome of a Gram-positive bacterium and a Gram-negative bacterium against irradiation. Solution of pure DNA and bacterial strains Listeria monocytogenes and Escherichia coli were irradiated using gamma and UV-C rays. Extracted DNA from bacteria and pure DNA samples were then analysed by ELISA using anti-CPDs and anti-6-4 PPs monoclonal antibodies. The results show that gamma rays, as well as UV-C rays, induce the formation of CPDs and 6-4 PPs in DNA. During UV-C irradiation, the three samples showed a difference in their sensitivity against formation of CPDs (P≤0.05). Pure DNA was the most sensitive while the genome of L. monocytogenes was the most resistant. Also during UV-C irradiation, the genome of L. monocytogenes was the only one to show a significant resistance against formation of 6-4 PPs (P≤0.05). During gamma irradiation, for both types of lesion, pure DNA and the genome of E. coli did not show significant difference in their sensitivity (P>0.05) while the genome of L. monocytogenes showed a resistance against formation of CPDs and 6-4 PPs.

  17. Evidence from mutation spectra that the UV hypermutability of xeroderma pigmentosum variant cells reflects abnormal, error-prone replication on a template containing photoproducts.

    PubMed Central

    Wang, Y C; Maher, V M; Mitchell, D L; McCormick, J J

    1993-01-01

    Xeroderma pigmentosum (XP) variant patients are genetically predisposed to sunlight-induced skin cancer. Fibroblasts derived from these patients are extremely sensitive to the mutagenic effect of UV radiation and are abnormally slow in replicating DNA containing UV-induced photoproducts. However, unlike cells from the majority of XP patients, XP variant cells have a normal or nearly normal rate of nucleotide excision repair of such damage. To determine whether their UV hypermutability reflected a slower rate of excision of photoproducts specifically during early S phase when the target gene for mutations, i.e., the hypoxanthine (guanine) phosphoribosyltransferase gene (HPRT), is replicated, we synchronized diploid populations of normal and XP variant fibroblasts, irradiated them in early S phase, and compared the rate of loss of cyclobutane pyrimidine dimers and 6-4 pyrimidine-pyrimidones from DNA during S phase. There was no difference. Both removed 94% of the 6-4 pyrimidine-pyrimidones within 8 h and 40% of the dimers within 11 h. There was also no difference between the two cell lines in the rate of repair during G1 phase. To determine whether the hypermutability resulted from abnormal error-prone replication of DNA containing photoproducts, we determined the spectra of mutations induced in the coding region of the HPRT gene of XP variant cells irradiated in early S and G1 phases and compared with those found in normal cells. The majority of the mutations in both types of cells were base substitutions, but the two types of cells differed significantly from each other in the kinds of substitutions, but the two types differed significantly from each other in the kinds of substitutions observed either in mutants from S phase (P < 0.01) or from G1 phase (P = 0.03). In the variant cells, the substitutions were mainly transversions (58% in S, 73% in G1). In the normal cells irradiated in S, the majority of the substitutions were G.C --> A.T, and most involved CC

  18. Theoretical study of the regioselectivity of the interaction of 3-methyl-4-pyrimidone and 1-methyl-2-pyrimidone with Lewis acids.

    PubMed

    Kasende, Okuma Emile; Muya, Jules Tshishimbi; Broeckaert, Lies; Maes, Guido; Geerlings, Paul

    2012-08-23

    A density functional theory (DFT) study is performed to determine the stability of the complexes formed between either the N or O site of 3-methyl-4-pyrimidone and 1-methyl-2-pyrimidone molecules and different ligands. The studied ligands are boron and alkali Lewis acids, namely, B(CH(3))(3), HB(CH(3))(2), H(2)B(CH(3)), BH(3), H(2)BF, HBF(2), BF(3), Li(+), Na(+), and K(+). The acids are divided into two groups according to their hardness. The reactivity predictions, according to the molecular electrostatic potential (MEP) map and the natural bond orbital (NBO) analysis, are in agreement with the calculated relative stabilities. Our findings reveal a strong regioselectivity with borane and its derivatives preferring the nitrogen site in both pyrimidone isomers, while a preference for oxygen is observed for the alkali acids in the 3-methyl-4-pyrimidone molecule. The complexation of 1-methyl-2-pyrimidone with these hard alkali acids does not show any discrimination between the two sites due to the presence of a continuous delocalized density region between the nitrogen and the oxygen atoms. The preference of boron Lewis acids toward the N site is due to the stronger B-N bond as compared to the B-O bond. The influence of fluorine or methyl substitution on the boron atom is discussed through natural orbital analysis (NBO) concentrating on the overlap of the boron empty p-orbital with the F lone pairs and methyl hyperconjugation, respectively. The electrophilicity of the boron acids gives a good overall picture of the interaction capabilities with the Lewis base.

  19. Photoproduction of leptophobic bosons

    NASA Astrophysics Data System (ADS)

    Fanelli, Cristiano; Williams, Mike

    2017-01-01

    We propose a search for photoproduction of leptophobic bosons that couple to quarks at the GlueX experiment at Jefferson Lab. We study in detail a new gauge boson that couples to baryon number B, and estimate that γ p\\to {pB} will provide the best sensitivity for B masses above 0.5 GeV. This search will also provide sensitivity to other proposed dark-sector states that couple to quarks. Finally, our results motivate a similar search for B boson electroproduction at the CLAS experiment.

  20. Photoproduction of Mesons

    NASA Astrophysics Data System (ADS)

    Schmieden, Hartmut; Klein, Friedrich

    2017-01-01

    B.1 is one of the experimental projects within the CRC16. It aims at the systematic investigation of the photoproduction of mesons off nucleons in order to understand reaction mechanisms and the relevant degrees of freedom in resonance formation. Of particular interest is the photoproduction of mesons heavier than the pion and resonances involving hidden or open strangeness. Essential hardware contributions have been made to the experimental programme of the CRC16 through tagging systems, and photon-beam polarisation and polarimetry. A new experiment has been set up within the framework of the BGO-OD collaboration. This combines a forward magnetic spectrometer with a central BGO calorimeter with charged particle recognition and identification. The BGO-OD experiment enables reconstruction of complex final states composed of both charged and neutral particles, complementary to the existing CBELSA/TAPS calorimeter which is optimised for multi-photon final states. Selected results of the 12-year CRC period are presented from both experiments.

  1. Human repair endonuclease incises DNA at cytosine photoproducts

    SciTech Connect

    Gallagher, P.E.; Weiss, R.B.; Brent, T.P.; Duker, N.J.

    1987-05-01

    The nature of DNA damage by uvB and uvC irradiation was investigated using a defined sequence of human DNA. A UV-irradiated, 3'-end-labeled, 92 base pair sequence from the human alphoid segment was incubated with a purified human lymphoblast endonuclease that incises DNA at non-dimer photoproducts. Analysis by polyacrylamide gel electrophoresis identified all sites of endonucleolytic incision as cytosines. These were found in regions of the DNA sequence lacking adjacent pyrimidines and therefore are neither cyclobutane pyrimidine dimers nor 6-4'-pyrimidines. Incision at cytosine photoproducts was not detected at loci corresponding to alkali-labile sites in either control or irradiated substrates. This demonstrates that the bands detected after the enzymic reactions were not the result of DNA strand breaks, base loss sites or ring-opened cytosines. The optimal wavelengths for formation of cytosine photoproducts are 270-295 nm, similar to those associated with maximal tumor yields in animal ultraviolet carcinogenesis studies. Irradiation by monochromatic 254 nm light resulted in reduced cytosine photoproduct formation. This human UV endonuclease has an apparently identical substrate specificity to E. coli endonuclease III. Both the human and bacterial enzymes incise cytosine moieties in UV irradiated DNA and modified thymines in oxidized DNA.

  2. Biological hydrogen photoproduction

    SciTech Connect

    Nemoto, Y.

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  3. Kaon photoproduction off proton

    NASA Astrophysics Data System (ADS)

    Skoupil, Dalibor; Bydžovský, Petr

    2016-11-01

    We have recently constructed our version of the Regge-plus-resonance (RPR) model and two variants of an isobar model for photoproduction of kaons on the proton, utilizing new experimental data from CLAS, LEPS, and GRAAL collaborations for adjusting free parameters of the models. Higher-spin nucleon (3/2 and 5/2) and hyperon (3/2) resonances were included using the consistent formalism by Pascalutsa and found to play an important role in data description. The set of chosen nucleon resonances in our new isobar models agrees well with the set of the most probable contributing states determined in the Bayesian analysis with the RPR model whilst only 6 out of 10 N*'s selected in the RPR fit of ours overlap with the nucleon resonant states in the Bayesian analysis. Results of two versions of the isobar model are compared to the new version of the RPR model and experimental data in the third-resonance region and their properties are discussed. We place an emphasis on the choice of resonances, the predictions in the forward- and backward-angle region as well as the choice of the hadron form factor.

  4. phi Photoproduction at CLAS

    SciTech Connect

    E. Anciant; G. Audit; T. Auger; M. Battaglieri; J.M. Laget; C. Marchand; K. McCormick; CLAS Collaboration

    2000-05-12

    The cross-section for phi meson photoproduction on the proton has been measured at a photon energy E_gamma = 3.6 GeV up to a four-momentum transfer -t = 4 GeV^2. A measurement of the differential cross-section at such high transfers, down to 100 pb/GeV^2, was only made possible thanks to the combination of the 100% duty cycle of CEBAF and the use of the large acceptance detector CLAS. At low four-momentum transfer, the differential cross-section is in agreement with previous measurements and is well accounted for by the exchange of the Pomeron. At large four-momentum transfer, above -t = 1 GeV^2, no previous data exist, and our results support a model where the Pomeron is resolved into its simplest component, two gluons. Taking into account the coupling of these gluons to any quark in the proton and the phi reproduces quite well the dependence in t of our cross-sections.

  5. Induction of UV photoproducts and DNA damage by solar simulator UV irradiation

    SciTech Connect

    Wolfreys, A.; Henderson, L.; Clingen, P.

    1997-10-01

    The recent increased incidence of skin cancer and the depletion of the ozone layer has increased interest in the ultraviolet (UV) component of natural sunlight and its role in the induction of skin cancer. Previous research on UV radiation has concentrated on UVC (254nm) but, as only UVB and UVA are present in natural sunlight, its relevance is unknown. We have investigated the induction of two forms of direct DNA damage - the pyrimidine dimer and the (6-4) photoproduct - in human DNA repair deficient XP-G (Xeroderma pigmentosum group G) lymphoblastoid cells following exposure to simulated sunlight. As exposure to natural sunlight is highly variable, a solar simulator lamp was used which is known to mimic natural sunlight at midday in Central Europe. Cells were irradiated on ice to minimise DNA repair and the relative induction of pyrimidine dimers and (6-4) photoproducts was measured using specific monoclonal antibodies and a computer assisted image analysis system. A time dependent increase in both cyclobutane dimer and (6-4) photoproduct antibody binding sites was seen. The increases in pyrimidine dimer and (6-4) photoproduct antibody binding sites differed to that reported with natural sunlight in the UK but was similar to that seen with a similar solar simulator lamp.

  6. Distribution and repair of bipyrimidine photoproducts in solar UV-irradiated mammalian cells. Possible role of Dewar photoproducts in solar mutagenesis.

    PubMed

    Perdiz, D; Grof, P; Mezzina, M; Nikaido, O; Moustacchi, E; Sage, E

    2000-09-01

    In order to better understand the relative contribution of the different UV components of sunlight to solar mutagenesis, the distribution of the bipyrimidine photolesions, cyclobutane pyrimidine dimers (CPD), (6-4) photoproducts ((6-4)PP), and their Dewar valence photoisomers (DewarPP) was examined in Chinese hamster ovary cells irradiated with UVC, UVB, or UVA radiation or simulated sunlight. The absolute amount of each type of photoproduct was measured by using a calibrated and sensitive immuno-dot-blot assay. As already established for UVC and UVB, we report the production of CPD by UVA radiation, at a yield in accordance with the DNA absorption spectrum. At biologically relevant doses, DewarPP were more efficiently produced by simulated solar light than by UVB (ratios of DewarPP to (6-4)PP of 1:3 and 1:8, respectively), but were detected neither after UVA nor after UVC radiation. The comparative rates of formation for CPD, (6-4)PP and DewarPP are 1:0.25 for UVC, 1:0. 12:0.014 for UVB, and 1:0.18:0.06 for simulated sunlight. The repair rates of these photoproducts were also studied in nucleotide excision repair-proficient cells irradiated with UVB, UVA radiation, or simulated sunlight. Interestingly, DewarPP were eliminated slowly, inefficiently, and at the same rate as CPD. In contrast, removal of (6-4)PP photoproducts was rapid and completed 24 h after exposure. Altogether, our results indicate that, in addition to CPD and (6-4)PP, DewarPP may play a role in solar cytotoxicity and mutagenesis.

  7. Heavy Quark Photoproduction at LHC

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Meneses, A. R.; Machado, M. V.

    2010-11-01

    In this work we calculate the inclusive and difractive photoproduction of heavy quarks in proton-proton collisions at LHC energies within the color dipole picture employing three phenomenological saturation models based on the color glass condensate formalism. Our results demonstrate that the experimental analyzes of these reactions is feasible and that the cross sections are sensitive to the underlying parton dynamics.

  8. Photoproduction of dissolved inorganic carbon in Swedish lakes

    NASA Astrophysics Data System (ADS)

    Koehler, B.; Landelius, T.; Tranvik, L. J.

    2012-04-01

    A substantial fraction of the dissolved organic carbon (DOC) in inland waters is mineralized to dissolved inorganic carbon (DIC) during passage towards the sea. Both microbial and photochemical mineralization have a share but there is currently no landscape-scale estimate of the contribution of photomineralization to total lake carbon dioxide emissions, restricting our understanding of inland-water C cycling. We use 1) DOC absorbance spectra measured during autumn 2009 in water samples from 1074 lakes distributed across Sweden, 2) light attenuation coefficients estimated based on correlations with absorption coefficients as established from literature data, 3) cloud-corrected, below-water-surface downwelling scalar irradiance spectra derived by modeling radiative transfer in the atmosphere and transmission into the water and 4) an apparent quantum yield spectrum determined in a humic lake, to calculate spectra of DIC photoproduction from 280 to 600 nm and from the water surface down to the mean lake depths. For each lake, we calculate DIC photoproduction rates on a daily base and integrate to obtain yearly flux estimates. Preliminary model results calculated for July 2009 show that, even though water color differed largely (25%- and 75%-quantiles of specific UV absorption coefficients at 254 nm (SUV A254) of 6.4 and 9.6 L mg C-1 m-1, respectively), depth-integrated DIC photoproduction rates showed a relatively small variation with a 25%-quantile of 12.0 and a 75%-quantile of 13.1 mg C m-2 day-1. These rather similar DIC photoproduction rates are explained by their different depth distributions: The brownest lake with a SUV A254 of 12.9 L mg C-1 m-1 had large surface DIC photoproduction rates of 887.9 mg C m-3 day-1 but photons were quickly attenuated with depth, with DIC photoproduction rates falling below 1 mg C m-3 day-1 already at ¯ 0.2 m depth (depth-integrated rate of 14.2 mg C m-2 day-1). The clearest lake with a SUV A254 of 1.4 L mg C-1 m-1 had nearly 100

  9. 7 CFR 6.4 - Investigations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Investigations. 6.4 Section 6.4 Agriculture Office of the Secretary of Agriculture IMPORT QUOTAS AND FEES General Provisions § 6.4 Investigations. (a) Section 22. The Administrator shall cause an investigation to be made whenever, based upon a...

  10. 7 CFR 6.4 - Investigations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Investigations. 6.4 Section 6.4 Agriculture Office of the Secretary of Agriculture IMPORT QUOTAS AND FEES General Provisions § 6.4 Investigations. (a) Section 22. The Administrator shall cause an investigation to be made whenever, based upon a...

  11. 7 CFR 6.4 - Investigations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Investigations. 6.4 Section 6.4 Agriculture Office of the Secretary of Agriculture IMPORT QUOTAS AND FEES General Provisions § 6.4 Investigations. (a) Section 22. The Administrator shall cause an investigation to be made whenever, based upon a...

  12. 7 CFR 6.4 - Investigations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Investigations. 6.4 Section 6.4 Agriculture Office of the Secretary of Agriculture IMPORT QUOTAS AND FEES General Provisions § 6.4 Investigations. (a) Section 22. The Administrator shall cause an investigation to be made whenever, based upon a...

  13. 27 CFR 6.4 - Jurisdictional limits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Jurisdictional limits. 6.4 Section 6.4 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS âTIED-HOUSEâ Scope of Regulations § 6.4 Jurisdictional limits. (a) General....

  14. Photoproduction of exotic baryon resonances

    NASA Astrophysics Data System (ADS)

    Karliner, Marek; Rosner, Jonathan L.

    2016-01-01

    We point out that the new exotic resonances recently reported by LHCb in the J / ψ p channel are excellent candidates for photoproduction off a proton target. This test is crucial to confirming the resonant nature of such states, as opposed to their being kinematical effects. We specialize to an interpretation of the heavier narrow state as a molecule composed of Σc and Dbar*, and estimate its production cross section using vector dominance. The relevant photon energies and fluxes are well within the capabilities of the GlueX and CLAS12 detectors at Thomas Jefferson National Accelerator Facility (JLAB). A corresponding calculation is also performed for photoproduction of an analogous resonance which is predicted to exist in the ϒp channel.

  15. Quasifree kaon photoproduction on nuclei

    SciTech Connect

    Frank Lee; T. MART; Cornelius Bennhold; Lester Wright

    2001-12-01

    Investigations of the quasifree reaction A({gamma}, K Y)B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.

  16. Meson Photoproduction Experiments with CLAS

    SciTech Connect

    Eugene Pasyuk

    2012-12-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to light baryon spectroscopy. Meson photoprodcution experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams and frozen spin polarized targets provide unique conditions for this type of experiments. This combination of experimental tools gives a remarkable opportunity to measure double polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete measurement became possible and will facilitate model independent extraction of the reaction amplitude. An overview of the experimental program and its current status together with recent results on double polarization measurements in π{sup +} photoproduction are presented.

  17. Bayesian analysis for kaon photoproduction

    SciTech Connect

    Marsainy, T. Mart, T.

    2014-09-25

    We have investigated contribution of the nucleon resonances in the kaon photoproduction process by using an established statistical decision making method, i.e. the Bayesian method. This method does not only evaluate the model over its entire parameter space, but also takes the prior information and experimental data into account. The result indicates that certain resonances have larger probabilities to contribute to the process.

  18. Structural role of two histidines in the (6-4) photolyase reaction

    PubMed Central

    Yamada, Daichi; Iwata, Tatsuya; Yamamoto, Junpei; Hitomi, Kenichi; Todo, Takeshi; Iwai, Shigenori; Getzoff, Elizabeth D.; Kandori, Hideki

    2015-01-01

    Photolyases (PHRs) are DNA repair enzymes that revert UV-induced photoproducts, either cyclobutane pyrimidine dimers (CPD) or (6-4) photoproducts (PPs), into normal bases to maintain genetic integrity. (6-4) PHR must catalyze not only covalent bond cleavage, but also hydroxyl or amino group transfer, yielding a more complex mechanism than that postulated for CPD PHR. Previous mutation analysis revealed the importance of two histidines in the active center, H354 and H358 for Xenopus (6-4) PHR, whose mutations significantly lowered the enzymatic activity. Based upon highly sensitive FTIR analysis of the repair function, here we report that both H354A and H358A mutants of Xenopus (6-4) PHR still maintain their repair activity, although the efficiency is much lower than that of the wild type. Similar difference FTIR spectra between the wild type and mutant proteins suggest a common mechanism of repair in which (6-4) PP binds to the active center of each mutant, and is released after repair, as occurs in the wild type. Similar FTIR spectra also suggest that a decrease in volume by the H-to-A mutation is possibly compensated by the addition of water molecule( s). Such a modified environment is sufficient for the repair function that is probably controlled by proton-coupled electron transfer between the enzyme and substrate. On the other hand, two histidines must work in a concerted manner in the active center of the wild-type enzyme, which significantly raises the repair efficiency. PMID:27493863

  19. 24 CFR 6.4 - Discrimination prohibited.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Discrimination prohibited. 6.4... COMMUNITY DEVELOPMENT ACT OF 1974 General Provisions § 6.4 Discrimination prohibited. (a) Section 109... benefits of, or be subjected to discrimination under any program or activity funded in whole or in...

  20. 24 CFR 6.4 - Discrimination prohibited.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Discrimination prohibited. 6.4... COMMUNITY DEVELOPMENT ACT OF 1974 General Provisions § 6.4 Discrimination prohibited. (a) Section 109... benefits of, or be subjected to discrimination under any program or activity funded in whole or in...

  1. 24 CFR 6.4 - Discrimination prohibited.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Discrimination prohibited. 6.4... COMMUNITY DEVELOPMENT ACT OF 1974 General Provisions § 6.4 Discrimination prohibited. (a) Section 109... benefits of, or be subjected to discrimination under any program or activity funded in whole or in...

  2. 24 CFR 6.4 - Discrimination prohibited.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Discrimination prohibited. 6.4... COMMUNITY DEVELOPMENT ACT OF 1974 General Provisions § 6.4 Discrimination prohibited. (a) Section 109... benefits of, or be subjected to discrimination under any program or activity funded in whole or in...

  3. 27 CFR 6.4 - Jurisdictional limits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Jurisdictional limits. 6.4 Section 6.4 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... transactions in interstate or foreign commerce in any such products; or (iii) The direct effect of...

  4. 27 CFR 6.4 - Jurisdictional limits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Jurisdictional limits. 6.4 Section 6.4 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... transactions in interstate or foreign commerce in any such products; or (iii) The direct effect of...

  5. 24 CFR 6.4 - Discrimination prohibited.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Discrimination prohibited. 6.4... COMMUNITY DEVELOPMENT ACT OF 1974 General Provisions § 6.4 Discrimination prohibited. (a) Section 109... benefits of, or be subjected to discrimination under any program or activity funded in whole or in...

  6. Complete Photo-production Experiments

    SciTech Connect

    D'Angelo, A.; Bartalini, O.; Fantini, A.; Schaerf, C.; Vegna, V.; Ardashev, K.; Bade, C.; Hicks, K.; Kizilgul, S.; Lucas, M.; Mahon, J.; Bellini, V.; Blecher, M.; Bocquet, J.-P.; Lleres, A.; Rebreyend, D.; Capogni, M.; Caracappa, A.; Kistner, O. C.; Miceli, L.

    2011-10-24

    The extraction of resonance parameters from meson photo-reaction data is a challenging effort, that would greatly benefit from the availability of several polarization observables, measured for each reaction channel on both proton and neutron targets. In the aim of obtaining such complete experiments, polarized photon beams and targets have been developed at facilities, worldwide. We report on the latest results from the LEGS and GRAAL collaborations, providing single and double polarization measurements on pseudo-scalar meson photo-production from the nucleon.

  7. 43 CFR 3141.6-4 - Qualifications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.6-4 Qualifications. Each bidder shall submit with the bid a statement over...

  8. 43 CFR 3141.6-4 - Qualifications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.6-4 Qualifications. Each bidder shall submit with the bid a statement over...

  9. 43 CFR 3141.6-4 - Qualifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.6-4 Qualifications. Each bidder shall submit with the bid a statement over...

  10. 43 CFR 3141.6-4 - Qualifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Leasing in Special Tar Sand Areas § 3141.6-4 Qualifications. Each bidder shall submit with the bid a statement over...

  11. Photoproduction total cross section and shower development

    NASA Astrophysics Data System (ADS)

    Cornet, F.; García Canal, C. A.; Grau, A.; Pancheri, G.; Sciutto, S. J.

    2015-12-01

    The total photoproduction cross section at ultrahigh energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.

  12. Photoproduction of the Xi Hyperons

    SciTech Connect

    John Price; J. Ducote; and BFK Nefkens

    2003-05-01

    Very little is known about the doubly-strange Xi hyperons. SU(3){sub F} symmetry, based on QCD, implies the existence of many Xi states yet to be found. A complete study of the excited Xi spectrum can also be used to study other related areas of nuclear physics, such as the s - d quark mass difference and Xi p scattering. We will report on a new approach to Xi physics, using the photoproduction process gamma p --> K{sup +} K{sup +} Xi{sup -}, in which the Xi is cleanly tagged by the missing mass of the (K{sup +}K{sup +}) system. We show the current status of this study with the CLAS detector at Jefferson Laboratory, and discuss how it relates to the above topics. We also comment on the future of this program.

  13. Mapping of UV photoproducts along the human P53 gene

    SciTech Connect

    Tornaletti, S.; Rozek, D.; Pfeifer, G.P.

    1994-12-31

    Methods to detect DNA adducts at the DNA sequence level in mammalian cells have been developed, and it is now possible to relate adduct frequency and repair efficiency with mutations at certain nucleotide positions in human cancer-relevant genes. Mutations in the p53 tumor suppressor gene have been found in a large proportion of human skin cancers. These mutations are predominantly C to T transitions and CC to TT double transition mutations, two types of base alterations specifically induced by UV light. In order to find possible correlations between adduct distribution and mutations at specific p53 sequences, we have mapped at single-base resolution the distribution of cyclobutane dimers (CBD) and (6-4) photoproducts along the p53 gene in UV-irradiated human skin fibroblasts by ligation-mediated polymerase chain reaction (LMPCR).

  14. Quantification of DNA photoproducts in mammalian cell DNA using radioimmunoassay.

    PubMed

    Berton, Thomas R; Mitchell, David L

    2012-01-01

    Over the past 25 years, the use of polyclonal and monoclonal antibodies to quantify DNA damage has burgeoned. Immunoassays offer distinct advantages over other analytical procedures currently used to measure DNA damage including adaptability, sensitivity, and selectivity. This combination of attributes allows for the development of powerful analytical techniques to visualize and quantify specific types of DNA damage in cells, tissue, and organisms exposed to subtoxic levels of xenobiotics with distinct advantages over the other procedures in the analysis of DNA damage in human and environmental samples. Radioimmunoassay (RIA) is readily applied to a variety of biological materials and has typically been used to measure DNA damage in cell and organ cultures, tissue sections and biopsies, buccal cells, bone marrow aspirates, peripheral blood lymphocytes, and urine. Here we describe the use of a very sensitive RIA for the specific quantitation of cyclobutane dimers and (6-4) photoproducts in DNA extracted from mammalian cells and tissues.

  15. Photoproduction of the kaon(+)kaon(-)(1750)

    NASA Astrophysics Data System (ADS)

    Mitchell, Ryan Edward

    2003-07-01

    While photoproduction has often been advertised as an important environment in which to study light meson spectroscopy, solid experimental results are sparse. In fact, beyond the relatively straightforward photoproduction of the rho, o, and φ mesons, the few results of exclusive photoproduction that do exist are poorly understood, and several, perhaps, have even been misinterpreted. After extensively reviewing the sometimes tenuous history of the exclusive photoproduction of the "rho'(1600)," the "opi0(1250)," the "o(1650)," and the "K+K -(1750)," new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K+K-(1750). This enhancement in low-pT K +K- pairs at a mass near 1750 MeV/c2 has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the JPC = 1-- φ(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K+ K-(1750), and based on precise measurements of its mass and width, and its absence from the K* K final state, the FOCUS data can finally render this interpretation implausible. In addition, several steps have been taken towards establishing a new interpretation. Based on limited angular analyses of its decay and the beam energy dependence of its production, we argue that, in the absence of any wild interference scenarios, the K+ K-(1750) has JPC ≠ 1--, and, in fact, the most likely assignment appears to be 2++. It is hoped that this work can help set the stage for future reevaluations and new insights in photoproduction.

  16. Prediction of p38 map kinase inhibitory activity of 3, 4-dihydropyrido [3, 2-d] pyrimidone derivatives using an expert system based on principal component analysis and least square support vector machine

    PubMed Central

    Shahlaei, M.; Saghaie, L.

    2014-01-01

    A quantitative structure–activity relationship (QSAR) study is suggested for the prediction of biological activity (pIC50) of 3, 4-dihydropyrido [3,2-d] pyrimidone derivatives as p38 inhibitors. Modeling of the biological activities of compounds of interest as a function of molecular structures was established by means of principal component analysis (PCA) and least square support vector machine (LS-SVM) methods. The results showed that the pIC50 values calculated by LS-SVM are in good agreement with the experimental data, and the performance of the LS-SVM regression model is superior to the PCA-based model. The developed LS-SVM model was applied for the prediction of the biological activities of pyrimidone derivatives, which were not in the modeling procedure. The resulted model showed high prediction ability with root mean square error of prediction of 0.460 for LS-SVM. The study provided a novel and effective approach for predicting biological activities of 3, 4-dihydropyrido [3,2-d] pyrimidone derivatives as p38 inhibitors and disclosed that LS-SVM can be used as a powerful chemometrics tool for QSAR studies. PMID:26339262

  17. Model selection for pion photoproduction

    NASA Astrophysics Data System (ADS)

    Landay, J.; Döring, M.; Fernández-Ramírez, C.; Hu, B.; Molina, R.

    2017-01-01

    Partial-wave analysis of meson and photon-induced reactions is needed to enable the comparison of many theoretical approaches to data. In both energy-dependent and independent parametrizations of partial waves, the selection of the model amplitude is crucial. Principles of the S matrix are implemented to a different degree in different approaches; but a many times overlooked aspect concerns the selection of undetermined coefficients and functional forms for fitting, leading to a minimal yet sufficient parametrization. We present an analysis of low-energy neutral pion photoproduction using the least absolute shrinkage and selection operator (LASSO) in combination with criteria from information theory and K -fold cross validation. These methods are not yet widely known in the analysis of excited hadrons but will become relevant in the era of precision spectroscopy. The principle is first illustrated with synthetic data; then, its feasibility for real data is demonstrated by analyzing the latest available measurements of differential cross sections (d σ /d Ω ), photon-beam asymmetries (Σ ), and target asymmetry differential cross sections (d σT/d ≡T d σ /d Ω ) in the low-energy regime.

  18. Model selection for pion photoproduction

    DOE PAGES

    Landay, J.; Doring, M.; Fernandez-Ramirez, C.; ...

    2017-01-12

    Partial-wave analysis of meson and photon-induced reactions is needed to enable the comparison of many theoretical approaches to data. In both energy-dependent and independent parametrizations of partial waves, the selection of the model amplitude is crucial. Principles of the S matrix are implemented to a different degree in different approaches; but a many times overlooked aspect concerns the selection of undetermined coefficients and functional forms for fitting, leading to a minimal yet sufficient parametrization. We present an analysis of low-energy neutral pion photoproduction using the least absolute shrinkage and selection operator (LASSO) in combination with criteria from information theory andmore » K-fold cross validation. These methods are not yet widely known in the analysis of excited hadrons but will become relevant in the era of precision spectroscopy. As a result, the principle is first illustrated with synthetic data; then, its feasibility for real data is demonstrated by analyzing the latest available measurements of differential cross sections (dσ/dΩ), photon-beam asymmetries (Σ), and target asymmetry differential cross sections (dσT/d≡Tdσ/dΩ) in the low-energy regime.« less

  19. Algal Systems for Hydrogen Photoproduction

    SciTech Connect

    Ghirardi, Maria L

    2015-10-08

    The National Renewable Energy Laboratory (NREL), under the guidance of Drs. Michael Seibert (retired, Fellow Emeritus) and Maria Ghirardi (Fellow), led 15 years of research addressing the issue of algal H2 photoproduction. This project resulted in greatly increased rates and yields of algal hydrogen production; increased understanding of the H2 metabolism in the green alga, Chlamydomonas reinhardtii; expanded our knowledge of other physiological aspects relevant to sustained algal photosynthetic H2 production; led to the genetic identification, cloning and manipulation of algal hydrogenase genes; and contributed to a broader, fundamental understanding of the technical and scientific challenges to improving the conversion efficiencies in order to reach the U.S. Department of Energy’s Fuel Cell Technologies Office’s targets. Some of the tangible results are: (i) 64 publications and 6 patents, (ii) international visibility to NREL, (iii) reinvigoration of national and international biohydrogen research, and (iv) research progress that helped stimulate new funding from other DOE and non-DOE programs, including the AFOSR and the DOE Office of Science.

  20. A model for pipi and pieta photoproduction

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Alvin Stanza

    We describe a model of general two-to-two-body and two-to-three-body hadronic reaction based on a phenomenological Lagrangian approach that satisfies two-body unitary and is relativistic. This model is used to study pieta photoproduction. Unitarity is ensured by using the Lippmann-Schwinger equation to iterate the vertices and dress the propagators to all orders, and by including all possible two-body and quasi-two-body intermediate channels. We also study different approximations of the intermediate momenta in a diagram. Gauge invariance is used as a criterion to choose the best approximation. This model has been tested by investigating the nonresonant interactions of pipi and pieta photoproduction, in which significant effects are observed. A preliminary comparison of our calculation to an existing pieta photoproduction study is made, and is shown to produce consistent results.

  1. Biological Systems for Hydrogen Photoproduction (Presentation)

    SciTech Connect

    Ghirardi, M. L.

    2012-05-01

    This presentation summarizes NREL biological systems for hydrogen photoproduction work for the DOE Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting, May 14-18, 2012. General goal is develop photobiological systems for large-scale, low cost and efficient H{sub 2} production from water (barriers AH, AI and AJ). Specific tasks are: (1) Address the O{sub 2} sensitivity of hydrogenases that prevent continuity of H{sub 2} photoproduction under aerobic, high solar-to-hydrogen (STH) light conversion efficiency conditions; and (2) Utilize a limited STH H{sub 2}-producing method (sulfur deprivation) as a platform to address or test other factors limiting commercial algal H{sub 2} photoproduction, including low rates due to biochemical and engineering mechanisms.

  2. Discovery and optimization of new benzimidazole- and benzoxazole-pyrimidone selective PI3Kβ inhibitors for the treatment of phosphatase and TENsin homologue (PTEN)-deficient cancers.

    PubMed

    Certal, Victor; Halley, Frank; Virone-Oddos, Angela; Delorme, Cécile; Karlsson, Andreas; Rak, Alexey; Thompson, Fabienne; Filoche-Rommé, Bruno; El-Ahmad, Youssef; Carry, Jean-Christophe; Abecassis, Pierre-Yves; Lejeune, Pascale; Vincent, Loic; Bonnevaux, Hélène; Nicolas, Jean-Paul; Bertrand, Thomas; Marquette, Jean-Pierre; Michot, Nadine; Benard, Tsiala; Below, Peter; Vade, Isabelle; Chatreaux, Fabienne; Lebourg, Gilles; Pilorge, Fabienne; Angouillant-Boniface, Odile; Louboutin, Audrey; Lengauer, Christoph; Schio, Laurent

    2012-05-24

    Most of the phosphoinositide-3 kinase (PI3K) kinase inhibitors currently in clinical trials for cancer treatment exhibit pan PI3K isoform profiles. Single PI3K isoforms differentially control tumorigenesis, and PI3Kβ has emerged as the isoform involved in the tumorigenicity of PTEN-deficient tumors. Herein we describe the discovery and optimization of a new series of benzimidazole- and benzoxazole-pyrimidones as small molecular mass PI3Kβ-selective inhibitors. Starting with compound 5 obtained from a one-pot reaction via a novel intermediate 1, medicinal chemistry optimization led to the discovery of compound 8, which showed a significant activity and selectivity for PI3Kβ and adequate in vitro pharmacokinetic properties. The X-ray costructure of compound 8 in PI3Kδ showed key interactions and structural features supporting the observed PI3Kβ isoform selectivity. Compound 8 achieved sustained target modulation and tumor growth delay at well tolerated doses when administered orally to SCID mice implanted with PTEN-deficient human tumor xenografts.

  3. Pharmacophore modelling and atom-based 3D-QSAR studies on N-methyl pyrimidones as HIV-1 integrase inhibitors.

    PubMed

    Reddy, Karnati Konda; Singh, Sanjeev Kumar; Dessalew, Nigus; Tripathi, Sunil Kumar; Selvaraj, Chandrabose

    2012-06-01

    Pharmacophore modelling and atom-based 3D-QSAR studies were carried out for a series of compounds belonging to N-methyl pyrimidones as HIV-1 integrase inhibitors. Based on the ligand-based pharmacophore model, we got 5-point pharmacophore model AADDR, with two hydrogen bond acceptors (A), two hydrogen bond donors (D) and one aromatic ring (R). The generated pharmacophore-based alignment was used to derive a predictive atom-based 3D-QSAR model for the training set (r(2) = 0.92, SD = 0.16, F = 84.8, N = 40) and for test set (Q(2) = 0.71, RMSE = 0.06, Pearson R = 0.90, N = 10). From these results, AADDR pharmacophore feature was selected as best common pharmacophore hypothesis, and atom-based 3D-QSAR results also support the outcome by means of favourable and unfavourable regions of hydrophobic and electron-withdrawing groups for the most potent compound 30. These results can be useful for further design of new and potent HIV-1 IN inhibitors.

  4. Photoproduction of the Lambda*(1520) Hyperon

    SciTech Connect

    Z. W. Zhao, H. Y. Lu, L. Graham, K. Park, R. W. Gothe

    2010-08-01

    The photoproduction of the Lambda*(1520) on both the proton and neutron have been studied by using the CLAS eg3 run data set. The reactions are gammad-->K+Lambda*(n) and gammad-->K0Lambda*(p) with Lambda*-->pK-. Preliminary total and differential cross sections have been extracted in the photon energy region 1.75 GeVphotoproduction of Lambda*(1520) on the neutron is reported, and we will extend the results on the proton to higher energies than in previous studies.

  5. Studies on porphyrin photoproducts in solution, cells, and tumor tissue

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Schneckenburger, Herbert; Rueck, Angelika C.; Koenig, Roland

    1994-07-01

    Light excitation of photosensitizing porphyrins leads to cytotoxic reactions. In addition, photobleaching and photoproduct formation occur indicating photosensitizer destruction. Photoproducts from hematoporphyrin (HP) fluoresce in aqueous solution at 642 nm, whereas photoproducts from protoporphyrin (PP) in hydrophobic environment emit around 670 nm and exhibit pronounced absorption at 665 nm. Photoproduct formation depends on singlet oxygen. The photoproducts exhibit faster fluorescence decay kinetics compared with nonirradiated porphyrins, as shown by time-grated spectroscopy and fluorescence decay measurements. Photoproduct fluorescence was observed during light exposure of cells and of tumor-bearing, nude mice, following administration of Hematoporphyrin Derivative (HpD), tetramethyl-HP, and PP. Photoconversion was also detected with naturally-occurring porphyrins (PP-producing bacteria) and ALA-simulated biosynthesis of PP in tumor tissue and in skin lesions of patients (psoriasis, mycosis fungoides). The efficiency of PDT with porphyrin photoproducts was found to be low in spite of the strong electronic transitions in the red spectral region.

  6. Photoproduction of charm particles at Fermilab

    SciTech Connect

    Cumalat, John P.

    1997-03-15

    A brief description of the Fermilab Photoproduction Experiment E831 or FOCUS is presented. The experiment concentrates on the reconstruction of charm particles. The FOCUS collaboration has participants from several Central American and Latin American institutions; CINVESTAV and Universidad Autonoma de Puebla from Mexico, University of Puerto Rico from the United States, and Centro Brasileiro de Pesquisas Fisicas in Rio de Janeiro from Brasil.

  7. Depopulation of highly excited singlet states of DNA model compounds: quantum yields of 193 and 245 nm photoproducts of pyrimidine monomers and dinucleoside monophosphates.

    PubMed

    Gurzadyan, G G; Görner, H

    1996-02-01

    Formation of uracil and orotic acid photodimers, uridine and 5'-UMP photohydrates, TpT photodimers and (6-4)photoproducts, dCpT photohydrates and (6-4)photoproducts and UpU, CpC and CpU photohydrates were studied in neutral deoxygenated aqueous solution at room temperature upon irradiation at either 193 or 254 nm. The photoproducts were identified and quantified and the contribution from photoionization to substrate decomposition, using lambda irr = 193 nm, was separated. The ratio of the quantum yields of respective stable products, eta = phi 193/phi 254, is indicative of the yield of internal conversion from the second to the first excited singlet state, S2-->S1. For the observed photodimers eta decreases from 0.94 for uracil to 0.7 for TpT and further to 0.55 for orotic acid. For the (6-4)photoproducts of TpT and dCpT eta = 0.5-0.8 and for the photohydrates in the cases of UpU, CpC, CpU and dCpT eta ranges from 0.55 to 1.

  8. Exclusive photoproduction of the cascade (Xi) hyperon

    SciTech Connect

    John Price; Bernard Nefkens; Justin Ducote; John Goetz; et. Al.

    2004-09-01

    We report on the first measurement of exclusive {Xi}{sup -}(1321) hyperon photoproduction in {gamma}p {yields} K{sup +}K{sup +}{Xi}{sup -} for 3.2 < E{sub {gamma}} < 3.9 GeV. The final state is identified by the missing mass in p({gamma}, K{sup +}K{sup +})X measured with the CLAS detector at Jefferson Laboratory. We have detected a significant number of the ground-state {Xi}{sup -}(132)1/2{sup +}, and have estimated the total cross section for its production. We have also observed the first excited state {Xi}{sup -}(1530)3/2{sup +}. Photoproduction provides a copious source of {Xi}'s. We discuss the possibilities of a search for the recently proposed {Xi}{sub 5}{sup --} and {Xi}{sub 5}{sup +} pentaquarks.

  9. Exclusive photoproduction of the cascade ({xi}) hyperons

    SciTech Connect

    Price, J.W.; Nefkens, B.M.K.; Ducote, J.L.; Goetz, J.T.; Adams, G.; Cummings, J.P.; Empl, A.; Frolov, V.; Hu, J.; Klusman, M.; Kubarovsky, V.; Li Ji; Napolitano, J.; Stoler, P.; Ungaro, M.; Witkowski, M.; Ambrozewicz, P.; Kramer, L.H.; Nasseripour, R.; Raue, B.A.

    2005-05-01

    We report on the first measurement of exclusive {xi}{sup -}(1321) hyperon photoproduction in {gamma}p{yields}K{sup +}K{sup +}{xi}{sup -} for 3.2Photoproduction provides a copious source of {xi}'s. We discuss the possibilities of a search for the recently proposed {xi}{sub 5}{sup -} and {xi}{sub 5}{sup +} pentaquarks.

  10. Hadronic form factors in kaon photoproduction

    SciTech Connect

    Syukurilla, L. Mart, T.

    2014-09-25

    We have revisited the effect of hadronic form factors in kaon photoproduction process by utilizing an isobaric model developed for kaon photoproduction off the proton. The model is able to reproduce the available experimental data nicely as well as to reveal the origin of the second peak in the total cross section, which was the main source of confusion for decades. Different from our previous study, in the present work we explore the possibility of using different hadronic form factors in each of the KΛN vertices. The use of different hadronic form factors, e.g. dipole, Gaussian, and generalized dipole, has been found to produce a more flexible isobar model, which can provide a significant improvement in the model.

  11. Single Meson Photoproduction at JLab Energies

    NASA Astrophysics Data System (ADS)

    Mathieu, Vincent; Joint Physics Analysis Center Team

    2016-09-01

    In this talk, I present the results from the Joint Physics Analysis Center about the photoproduction of a single meson (pseudoscalar or vector meson). We have developed the theoretical formalism to analysis forthcoming data at the, recently upgraded, JLab facility. We also present prediction for observables in the energy range of Eg = 5-11 GeV. Material (codes, notes, sim- ulations, etc) can be found online at the JPAC interactive website: http://www.indiana.edu/ jpac/index.html

  12. Photoproduction of Neutral Kaons on Deuterons

    NASA Astrophysics Data System (ADS)

    Beckford, Brian

    2006-11-01

    Experimentation to greater understand the strangeness production mechanism can be performed by observing the electromagnetic interaction that leads to Kaon photoproduction. The n (γ, K^0) λ reaction may assist in answering questions about the strangeness photo-production process. An experiment into the elementary Kaon photoproduction process was investigated in an experiment conducted at the Laboratory of Nuclear Science of Tohoku University (LNS) using the Neutral Kaon Spectrometer. (NKS). The experiment was conducted by the d (γ, K^0) reaction. K^0 will be measured in the K^0->π^+π^- decay chain by the NKS. The NKS implements many detectors working in coincidence: These ranging from the Tagged Photon Beam generated by the 1.2 GeV Electron beam via bremsstrahlung, an Inner Plastic Scintillator Hodoscope (IH), a Straw Drift Chamber (SDC), a Cylindrical Drift Chamber (CDC), and an Outer Plastic Scintillator Hodoscope. Due to the background produced through the γ-> e+e- process, electron veto counters (EV) were placed in the middle of the OH to reject charged particles in the horizontal plane of the beam line. Preliminary analysis of the data indicates the need for pulse height correction. This was achieved by analysis of the Inner and Outer hodoscopes, and determining the energy deposit in the scintillators.

  13. Characterization and differential expression of CPD and 6-4 DNA photolyases in Xiphophorus species and interspecies hybrids.

    PubMed

    Walter, Dylan J; Boswell, Mikki; Volk de García, Sara M; Walter, Sean M; Breitenfeldt, Erik W; Boswell, William; Walter, Ronald B

    2014-06-01

    Among the many Xiphophorus interspecies hybrid tumor models are those that exhibit ultraviolet light (UVB) induced melanoma. In previous studies, assessment of UVB induced DNA damage and nucleotide excision DNA repair has been performed in parental lines and interspecies hybrids. Species and hybrid specific differences in the levels of DNA damage induced and the dark repair rates for cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine pyrimidine photoproducts (6-4PPs) have been reported. However, UVB induced DNA lesions in Xiphophorus fishes are thought to primarily be repaired via light dependent CPD and 6-4PP specific photolyases. Photolyases are of evolutionary interest since they are ancient and presumably function solely to ameliorate the deleterious effects of UVB exposure. Herein, we report results from detailed studies of CPD and 6-4PP photolyase gene expression within several Xiphophorus tissues. We determined photolyase gene expression patterns before and after exposure to fluorescent light in X. maculatus, X. couchianus, and for F1 interspecies hybrids produced from crossing these two parental lines (X. maculatus Jp 163 B×X. couchianus). We present novel results showing these two photolyase genes exhibit species, tissue, and hybrid-specific differences in basal and light induced gene expression.

  14. 1 CFR 6.4 - Monthly list of sections affected.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1 General Provisions 1 2011-01-01 2011-01-01 false Monthly list of sections affected. 6.4 Section 6.4 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER INDEXES AND ANCILLARIES § 6.4 Monthly list of sections affected. A monthly list of sections of the Code...

  15. 1 CFR 6.4 - Monthly list of sections affected.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1 General Provisions 1 2010-01-01 2010-01-01 false Monthly list of sections affected. 6.4 Section 6.4 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER INDEXES AND ANCILLARIES § 6.4 Monthly list of sections affected. A monthly list of sections of the Code...

  16. 39 CFR 6.4 - Attendance by conference telephone call.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Attendance by conference telephone call. 6.4 Section 6.4 Postal Service UNITED STATES POSTAL SERVICE THE BOARD OF GOVERNORS OF THE U.S. POSTAL SERVICE MEETINGS (ARTICLE VI) § 6.4 Attendance by conference telephone call. For regularly scheduled meetings...

  17. Antibaryon photoproduction using CLAS at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Phelps, W.; Guo, L.

    2016-05-01

    There is little known about baryon-antibaryon photoproduction mechanisms. Three reactions, γ p →p p p ¯, γ p →p p n ¯π-, and γ p →p n p ¯π+ have been investigated for the photon energy range of 3.95-5.45 GeV. The data were from the g12 run period taken with the CLAS detector using a liquid hydrogen target in Hall B at Thomas Jefferson National Accelerator Facility. This experiment had high statistics, with an integrated luminosity of 68 pb-1. General features of the data and preliminary cross sections are presented.

  18. Photoproduction of neutral pions off protons

    NASA Astrophysics Data System (ADS)

    Crede, V.; Sparks, N.; Wilson, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, Chr.; Gregor, R.; Gridnev, A.; Gutz, E.; Hillert, W.; Hoffmeister, P.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.

    2011-11-01

    Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector in the reaction γp→pπ0 for photon energies between 0.85 and 2.50 GeV. The π0 mesons are observed in their dominant neutral decay mode: π0→γγ. For the first time, the differential cross sections cover the very forward region, θc.m.<60∘. A partial-wave analysis of these data within the Bonn-Gatchina framework observes the high-mass resonances G17(2190), D13(2080), and D15(2070).

  19. Measurements of Heavy Flavour Photoproduction at HERA

    NASA Astrophysics Data System (ADS)

    Mergelmeyer, Sebastian

    2013-12-01

    Recent measurements of open charm and beauty photoproduction with the H1 and ZEUS detectors at the e±p-collider HERA are presented. These measurements reveal valuable details about the inner structure of the proton and the photon, the fragmentation of quarks into jets, and allow tests of perturbative QCD. Various experimental techniques were employed to identify and extract the heavy-quark signal. Their results are discussed, and compared to each other and to NLO QCD calculations. In addition the determination of charm fragmentation fractions is presented.

  20. Higgs boson photoproduction at the LHC

    SciTech Connect

    Ducati, M. B. Gay; Silveira, G. G.

    2011-07-15

    We present the current development of the photoproduction approach for the Higgs boson with its application to pp and pA collisions at the LHC. We perform a different analysis for the Gap Survival Probability, where we consider a probability of 3% and also a more optimistic value of 10% based on the HERA data for dijet production. As a result, the cross section for the exclusive Higgs boson production is about 2 fb and 6 fb in pp collisions and 617 and 2056 fb for pPb collisions, considering the gap survival factor of 3% and 10%, respectively.

  1. Status of Meson Photoproduction Experiments with CLAS

    SciTech Connect

    Pasyuk, Eugene A.

    2014-01-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Meson photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams in combination with longitudinally and transversely polarized frozen spin targets provide unique conditions for this type of experiments. For the first time, a complete or nearly complete measurement became possible and will allow model independent extraction of the reaction amplitude. The measurements were complete with both proton and deuteron targets. An overview of the collected experimental data will be presented.

  2. Hydrogen photoproduction of A. Variabilis incorporated in a photobioreactor

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Guo; Hall, David O.; Rao, Krishna K.; Tsygankov, Anatoly A.; Sveshnikov, Dmitry A.

    1998-03-01

    H2 photoproduction and nitrogenase activities in two strains of Anabaena variabilis marked wild type ATCC 29413 and mutant PK84 exposed to thermal stress (temperature higher than the normal incubation temperature of 30°C) were studied. Cultures of both strains collected from any interval of logarithmic growth phase exhibited high H2 photoproduction and nitrogenase activities when exposed to limited time heat shock during the assay process. In contrast, the algal H2 photoproduction rate of both strains fluctuated with long term thermal stress caused by increasing the growth temperature from 30°C to 36°C. The changes of nitrogenase (the key H2 photobiosynthetic enzyme) activities in the mutant PK84 showed variation tendency similar to that of H2 photoproduction during exposure to thermal stress, indicating that fluctuation of H2 photoproduction in the mutant was mainly due to the variation of nitrogenase activities. A temporary maximal H2 photoproduction in the mutant PK84 (wild type ATCC29413) was observed when cells grew at 36°C for 14 (6) days. However, the responses of nitrogenase activities in the wild type to thermal stress were not completely similar to those in the mutant in spite of similar variations of H2 photoproduction in both strains. The data obtained in these studies suggested that the activities of other enzymes (in the wild strain) involved in H2 photoproduction were affected by thermal stress since H2 photoproduction maximized or dropped to 0 without variation tendency similar to that of nitrogenase activities. Furthermore, an enhancement of H2 photoproduction speed of the mutant strain cultured in a 4.4 L laboratory photobioreactor was also observed when it was subjected to short time continuous charge of argon, and temperature rise. All these results indicated that high temperature plays an important role in the photo-autotrophic H2 photoproduction, and that long term thermal stress is unfavourable for net H2 photoproduction in both strains

  3. Carbon monoxide photoproduction from rice and maize leaves

    NASA Astrophysics Data System (ADS)

    Yonemura, S.; Morokuma, M.; Kawashima, S.; Tsuruta, H.

    We investigated CO photoproduction from intact leaves of rice ( Oryza sativa L.) and maize ( Zea mays L.) by laboratory experiments. CO photoproduction showed positive correlation with light intensity and was positively dependent on oxygen concentration. The average CO photoproduction was 2.6±0.3×10 10 molecules cm -2 s -1 from rice leaves and 2.2±0.1×10 10 molecules cm -2 s -1 from maize leaves ( n=5) at a radiation intensity of 49 mW cm -2. CO photoproduction from senescent rice leaves was 9 times greater (25.7±1.5×10 10 molecules cm -2 s -1, n=2) at the same radiation intensity than from live leaves, and responded slowly to changes in oxygen concentration and light intensity. CO photoproduction showed no correlation with CO 2 concentration or humidity. This indicates that CO photoproduction in leaves is not directly controlled by carbon metabolism or stomatal conductance. The lack of dependence on stomatal conductance leads to the conclusion that the diffusion of CO from inside the leaves to the atmosphere is not a controlling factor for CO photoproduction from rice and maize leaves.

  4. GlueX: Meson Spectroscopy in Photoproduction

    SciTech Connect

    Salgado, Carlos; Smith, Elton S.

    2014-03-01

    The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.

  5. Photoproduction of the rho meson and its magnetic moments

    SciTech Connect

    Kaneko, Hiromi; Hosaka, Atsushi; Scholten, Olaf

    2011-10-21

    We study photoproduction of {rho} meson in a model of hidden local symmetry. We introduce the {rho} meson on a hidden gauge boson and phenomenological {rho} meson-nucleon Lagrangian is constructed respecting chiral symmetry. It turns out that the {sigma}-exchange interaction plays an important role in neutral {rho} meson photoproduction to reproduce the experimental cross sections. In charged {rho} meson photoproduction, the model takes into account the {rho} meson magnetic moments from the three-point vertex in the kinetic terms. We show that the magnetic moment of the charged {rho} meson has a significant effect on the total cross sections in proportion to the photon energies.

  6. Enzymic cleavage of purine ultraviolet photoproducts formed at biologically significant wavelengths

    SciTech Connect

    Gallagher, P.E.; Duker, N.J.

    1986-05-01

    A paradox of ultraviolet carcinogenesis research has been that maximal absorption and mutagenesis occurs at 254 nm irradiation, while the greatest tumor yield in irradiated animals has been at wavelengths between 275 and 300 nm. Ambient actinic radiation contains mostly wavelengths above 280 nm with no substantial 254 nm component. Therefore, the authors investigated formation of DNA damage by 250-400 nm irradiation. Irradiated, 3'-end-labeled, 92 base pair sequence of the human alphoid segment was incubated with endonuclease v, purified from T4-infected E. coli, or with a crude extract of M. luteus. Analysis by gel electrophoresis showed that besides pyrimidine photodimers, previously unreported photoproducts were incised. These are not 6-4'(pyrimidin-2'-one)-pyrimidines, apurinic or apyrimidinic sites, or ring-opened purines. The new products are at specific purine loci and are formed in quantities similar to pyridimine dimers. The optimal wavelengths for their formation are 275-295 nm, similar to the maximum peak of actinic carcinogenesis. The enzyme incising these products is inactivated by different heating conditions than the pyrimidine dimer-DNA glycosylase, and they appear to be separable by column chromatography. The authors propose that a novel family of photoproducts, possibly purine-containing dimers, are incised by previously uncharacterized DNA repair enzymes.

  7. 15 CFR 6.4 - Adjustments to penalties.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6.4 Commerce and Foreign Trade Office of the Secretary of Commerce CIVIL MONETARY PENALTY INFLATION ADJUSTMENTS § 6.4 Adjustments to penalties. The civil monetary penalties provided by law within the... Sensing Policy Act of 1992, from $11,000 to $11,000. (2) 15 U.S.C. 5658(c), Land Remote Sensing Policy...

  8. 31 CFR 6.4 - Eligibility of applicants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... public or private organization with a net worth of not more than $5 million and not more than 500... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Eligibility of applicants. 6.4 Section 6.4 Money and Finance: Treasury Office of the Secretary of the Treasury APPLICATIONS FOR...

  9. Coupled channel model of the scalar isovector meson photoproduction

    NASA Astrophysics Data System (ADS)

    Bibrzycki, Ł.; Kamiński, R.

    2017-03-01

    We present the coupled channel model of the scalar isovector resonance photoproduction including the πη, KK̅ and πη' channels and calculate resulting mass distribution and the cross section in the πη channel. We show that the shape of this mass distribution, is strongly affected by the phase of background amplitude. We also discuss the effect of inclusion the πη' channel on the overall isovector photoproduction process.

  10. Heavy quark photoproduction in pp coherent interactions at LHC

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Machado, M. V. T.; Meneses, A. R.

    2010-02-01

    In this work we analyze the possibility of constraining the QCD dynamics at high energies studying the heavy quark photoproduction at LHC in coherent interactions. The rapidity distribution and total cross section for charm and bottom production are estimated using three different phenomenological saturation models which successfully describe the HERA data. Our results indicate that the experimental study of the inclusive heavy quark photoproduction can be very useful to discriminate between the classical and quantum versions of the Color Glass Condensate (CGC) formalism.

  11. Photoproduction models for total cross section and shower development

    NASA Astrophysics Data System (ADS)

    Cornet, Fernando; Garcia Canal, Carlos; Grau, Agnes; Pancheri, Giulia; Sciutto, Sergio

    2015-08-01

    A model for the total photoproduction cross section, based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.

  12. Modelling vibrational coherence in the primary rhodopsin photoproduct

    NASA Astrophysics Data System (ADS)

    Weingart, O.; Garavelli, M.

    2012-12-01

    Molecular dynamics simulations of the rhodopsin photoreaction reveal coherent low frequency oscillations in the primary photoproduct (photorhodopsin), with frequencies slightly higher than observed in the experiment. The coherent molecular motions in the batho-precursor can be attributed to the activation of ground state vibrational modes in the hot photo-product, involving out-of-plane deformations of the carbon skeleton. Results are discussed and compared with respect to spectroscopic data and suggested reaction mechanisms.

  13. Suppression factors in diffractive photoproduction of dijets

    NASA Astrophysics Data System (ADS)

    Klasen, Michael; Kramer, Gustav

    2010-11-01

    Now that new publications of H1 data for the diffractive photoproduction of dijets, which overlap with the earlier published H1 data and the recently published data of the ZEUS collaboration, have appeared, we have recalculated the cross sections for this process in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that the NLO cross sections disagree with the data, showing that factorization breaking occurs at that order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse-energy cut. However, by suppressing only the resolved contribution, also reasonably good agreement with all the data is found with a suppression factor independent of the transverse-energy cut.

  14. Toxic photoproducts of phenanthrene in sunlight

    SciTech Connect

    McConkey, B.L.; Duxbury, C.L.; El-Alawi, Y.S.; Dixon, D.G.; Greenberg, B.M.

    1995-12-31

    Phenanthrene, one of the most prevalent PAHs, undergoes a significant increase in toxicity on exposure to sunlight. Over a period of several days exposure to light, the toxicity of an aqueous phenanthrene solution increased dramatically. This increase in toxicity is largely due to the primary photoproduct, 9,10-phenanthrenequinone. This compound is more toxic than phenanthrene at equimolar concentrations, and is more water soluble than phenanthrene, increasing its bioavailability. Although many PAHs are potent photosensitizers, phenanthrene did not exhibit a significant increase in toxicity due to photosensitization. Photo-oxidation was the principal cause of photoinduced toxicity, with 9,10-phenanthrenequinone being formed via an unstable intermediate. In addition, mixtures of phenanthrene and 9,10-phenanthrenequinone exhibited potentially synergistic effects, as shown by joint toxicity testing using Photobacterium phosphoreum. Thus, mixtures of oxidized PAHs produced by photoaction in the environment create a significant risk to the biosphere.

  15. The photoproduction of circumstellar OH maser shells

    NASA Technical Reports Server (NTRS)

    Huggins, P. J.; Glassgold, A. E.

    1982-01-01

    The structure of OH shells formed from the photodestruction of H2O by ambient UV photons in the thick, expanding envelopes around cool evolved stars is investigated. The properties of the shells are governed mainly by the envelope shielding which in turn is primarily controlled by the mass-loss rate M. The peak OH densities and column densities through the shells are, respectively, slowly decreasing and increasing functions of M. The characteristic radii of the shells also depend on M, increasing from about 4(15) cm for M = 1(-6) solar mass/yr to about 1(17) cm for M = 1(-4) solar mass/yr; this dependence is well matched by recent observational data, and lends support to the OH photoproduction mechanism.

  16. Microbial degradation of thidiazuron and its photoproduct.

    PubMed

    Benezet, H J; Knowles, C O

    1982-01-01

    Degradation of the cotton defoliant thidiazuron and its photoproduct photothidiazuron by soil and thirteen species of microorganisms was examined. Aspergillus versicolor, Torula rosea, and Flavobacter sp. were most active in degrading thidiazuron. Unknown water-soluble metabolites and phenylurea were the major products. A. versicolor and Penicillium cyclopium were most active in degrading photothidiazuron. 4-Hydroxyphenylphotothidiazuron was the major organosoluble product formed by A. versicolor; phenylurea and an unidentified metabolite constituted the major organosoluble products from P. cyclopium. Both microbes also formed appreciable water-soluble metabolites. Radioactive carbon dioxide was formed from thidiazuron-aniline-14C by Oscillatoria sp. but not by Chlorella sp., suggesting that the former algal species utilized the defoliant as an energy source.

  17. Photoproduction of scalar mesons at medium energies

    SciTech Connect

    Da Silva, M. L.; Machado, M. V.

    2013-03-25

    In this work we will focus on photoproduction of mesons states a{sub 0}(980), f{sub 0}(1500) and f{sub 0}(1710). The f{sub 0}(1500) and f{sub 0}(1710) mesons will be considered in distinct mixing possibilities and assuming that a{sub 0}(980) is member of the ground-state nonet. The theoretical formalism is the Regge approach with reggeized {rho} and {omega} exchange. The differential and integrated total cross section are computed for the cases of the mesons a{sub 0}(980), f{sub 0}(1500) and f{sub 0}(1710) focusing the GlueX energy regime with photon energy E = 9 GeV.

  18. Meson photoproduction from the nucleon at CLAS

    SciTech Connect

    Daniel P. Watts

    2012-01-01

    The excitation spectrum of the nucleon provides a stringent constraint on the dynamics and interactions of its internal constituents and therefore probes the mechanism of confinement in the light quark sector. Our detailed knowlege of this excitation spectrum is poor, with many predicted states not yet observed in experiment and many 'established' states having poorly known properties. To address these shortcomings a worldwide effort is currently underway exploiting the latest generation of electron and photon beams in detailed studies of meson photoproduction from nucleon targets. A major contribution to this effort will come from the experimental programme at Jefferson Lab exploiting the frozen spin target (FROST) with the CLAS spectrometer. The status of this project will be presented along with preliminary results and analyses.

  19. Model discrimination in pseudoscalar-meson photoproduction

    NASA Astrophysics Data System (ADS)

    Nys, J.; Ryckebusch, J.; Ireland, D. G.; Glazier, D. I.

    2016-08-01

    To learn about a physical system of interest, experimental results must be able to discriminate among models. We introduce a geometrical measure to quantify the distance between models for pseudoscalar-meson photoproduction in amplitude space. Experimental observables, with finite precision, map to probability distributions in amplitude space, and the characteristic width scale of such distributions needs to be smaller than the distance between models if the observable data are going to be useful. We therefore also introduce a method for evaluating probability distributions in amplitude space that arise as a result of one or more measurements, and show how one can use this to determine what further measurements are going to be necessary to be able to discriminate among models.

  20. Photocouplings at the pole from pion photoproduction

    DOE PAGES

    Ronchen, D.; Doring, M.; Huang, F.; ...

    2014-06-24

    The reactions γp → π0p and γp → π+n are analyzed in a semi-phenomenological approach up to E ~ 2.3 GeV. Fits to differential cross section and single and double polarization observables are performed. A good overall reproduction of the available photoproduction data is achieved. The Julich2012 dynamical coupled-channel model -which describes elastic πN scattering and the world data base of the reactions πN → ηN, KΛ, and KΣ at the same time– is employed as the hadronic interaction in the final state. Furthermore, the framework guarantees analyticity and, thus, allows for a reliable extraction of resonance parameters in termsmore » of poles and residues. In particular, the photocouplings at the pole can be extracted and are presented.« less

  1. Photocouplings at the pole from pion photoproduction

    SciTech Connect

    Ronchen, D.; Doring, M.; Huang, F.; Haberzettl, H.; Haidenbauer, J.; Hanhart, C.; Krewald, S.; MeiBner, U. -G.; Nakayama, K.

    2014-06-24

    The reactions γp → π0p and γp → π+n are analyzed in a semi-phenomenological approach up to E ~ 2.3 GeV. Fits to differential cross section and single and double polarization observables are performed. A good overall reproduction of the available photoproduction data is achieved. The Julich2012 dynamical coupled-channel model -which describes elastic πN scattering and the world data base of the reactions πN → ηN, KΛ, and KΣ at the same time– is employed as the hadronic interaction in the final state. Furthermore, the framework guarantees analyticity and, thus, allows for a reliable extraction of resonance parameters in terms of poles and residues. In particular, the photocouplings at the pole can be extracted and are presented.

  2. Photoproduction of scalar mesons at CLAS

    NASA Astrophysics Data System (ADS)

    Chandavar, Shloka; Hicks, Kenneth; Weygand, Dennis; CLAS Collaboration

    2013-10-01

    A single gluon, which carries color charge, cannot exist independently outside a hadron. Lattice QCD calculations in pure SU(3), however, predict the existence of glueballs which are bound states of two or more gluons. In the real world, the challenge to identify glueballs experimentally is the fact they mix with meson states. The f0 (1500) is one of several candidates for the lightest glueball, with JPC =0++ . We investigate the presence of this particle in photoproduction by analyzing the reaction γp -->fJ p -->KS0KS0 p --> 2 (π+π-) p . This reaction was studied using data from the g12 experiment performed using the CLAS detector at Jefferson Lab. A preliminary partial wave analysis, performed on the KS0KS0 invariant mass spectrum, will be presented. These results update those presented for this reaction channel at previous conferences. This work is supported by grant from NSF.

  3. DETERMINATION OF APPARENT QUANTUM YIELD SPECTRA FOR THE FORMATION OF BIOLOGICALLY LABILE PHOTOPRODUCTS

    EPA Science Inventory

    Quantum yield spectra for the photochemical formation of biologically labile photoproducts from dissolved organic matter (DOM) have not been available previously, although they would greatly facilitate attempts to model photoproduct formation rates across latitudinal, seasonal, a...

  4. REV1 restrains DNA polymerase zeta to ensure frame fidelity during translesion synthesis of UV photoproducts in vivo.

    PubMed

    Szüts, Dávid; Marcus, Adam P; Himoto, Masayuki; Iwai, Shigenori; Sale, Julian E

    2008-12-01

    Exposure to ultraviolet light induces a number of forms of damage in DNA, of which (6-4) photoproducts present the most formidable challenge to DNA replication. No single DNA polymerase has been shown to bypass these lesions efficiently in vitro suggesting that the coordinate use of a number of different enzymes is required in vivo. To further understand the mechanisms and control of lesion bypass in vivo, we have devised a plasmid-based system to study the replication of site-specific T-T(6-4) photoproducts in chicken DT40 cells. We show that DNA polymerase zeta is absolutely required for translesion synthesis (TLS) of this lesion, while loss of DNA polymerase eta has no detectable effect. We also show that either the polymerase-binding domain of REV1 or ubiquitinated PCNA is required for the recruitment of Polzeta as the catalytic TLS polymerase. Finally, we demonstrate a previously unappreciated role for REV1 in ensuring bypass synthesis remains in frame with the template. Our data therefore suggest that REV1 not only helps to coordinate the delivery of DNA polymerase zeta to a stalled primer terminus but also restrains its activity to ensure that nucleotides are incorporated in register with the template strand.

  5. η and η' photoproduction off the proton

    NASA Astrophysics Data System (ADS)

    Sparks, Nathan; Crede, Volker

    2009-05-01

    The photoproduction of η and η' mesons (I=1/2) serves as an isospin filter facilitating the study of N^* resonances. Total and differential cross sections for these mesons have been determined using the Crystal Barrel CsI(Tl) calorimeter at ELSA, University of Bonn in Germany, in the energy range Eγ = 850 to 2550 MeV by analyzing the neutral decay modes: η->30̂, η->2γ, and η'->20̂η. In this experiment, the BaF2 spectrometer TAPS was placed in the forward direction increasing the solid angle coverage to nearly 4π. For the first time, these measurements cover the full angular range in cms ̂meson. In separate beam time using the same detector setup, linearly polarized photons were produced by coherent bremsstrahlung off a diamond radiator to allow the extraction of the photon beam asymmetry, σ. Preliminary results for pseudoscalar mesons in the range Eγ = 1100 to 1700 MeV are discussed.

  6. Photoproduction of ω mesons off the proton

    NASA Astrophysics Data System (ADS)

    Wilson, A.; Crede, V.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Brinkmann, K. T.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Fuchs, M.; Funke, Chr.; Gregor, R.; Gridnev, A.; Gutz, E.; Hannappel, J.; Hillert, W.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Jude, T.; Junkersfeld, J.; Kalinowsky, H.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schmidt, C.; Schmieden, H.; Shende, S.; Sokhoyan, V.; Sparks, N.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.; Wiedner, U.

    2015-10-01

    The differential cross sections and unpolarized spin-density matrix elements for the reaction γp → pω were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the ω meson, ω →π0 γ. The cross sections cover the full angular range and show the full extent of the t-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn-Gatchina partial wave analysis (PWA). The dominant contribution to ω photoproduction near threshold was found to be the 3 /2+ partial wave, which is primarily due to the sub-threshold N (1720) 3 /2+ resonance. At higher energies, pomeron-exchange was found to dominate whereas π-exchange remained small. These t-channel contributions as well as further contributions from nucleon resonances were necessary to describe the entire dataset: the 1 /2-, 3 /2-, and 5 /2+ partial waves were also found to contribute significantly.

  7. Photoproduction of η{^' -mesons off the deuteron

    NASA Astrophysics Data System (ADS)

    Jaegle, I.; Mertens, T.; Fix, A.; Huang, F.; Nakayama, K.; Tiator, L.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, C.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Höffgen, S.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Messchendorp, J. G.; Metag, V.; Nikonov, V. A.; Nanova, M.; Novinski, D. V.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, C.

    2011-01-01

    Quasi-free photoproduction of η{^' -mesons off nucleons bound in the deuteron has been measured with the combined Crystal Barrel - TAPS detector. The experiment was done at a tagged photon beam of the ELSA electron accelerator in Bonn for incident photon energies from the production threshold up to 2.5GeV. The η{^' -mesons have been detected in coincidence with recoil protons and recoil neutrons. The quasi-free proton data are in good agreement with the results for free protons, indicating that nuclear effects have no significant impact. The coincidence with recoil neutrons provides the first data for the γ n rightarrow n η{^' reaction. In addition, also first estimates for coherent η{^' -production off the deuteron have been obtained. In agreement with model predictions, the total cross-section for this channel is found to be very small, at most at the level of a few nb. The data are compared to model calculations taking into account contributions from nucleon resonances and t -channel exchanges.

  8. Double polarisation experiments in meson photoproduction

    NASA Astrophysics Data System (ADS)

    Hartmann, Jan

    2016-11-01

    One of the remaining challenges within the standard model is to gain a good understanding of QCD in the non-perturbative regime. A key step towards this aim is baryon spectroscopy, investigating the spectrum and the properties of baryon resonances. To gain access to resonances with small πN partial width, photoproduction experiments provide essential information. Partial wave analyses need to be performed to extract the contributing resonances. Here, a complete experiment is required to unambiguously determine the contributing amplitudes. This involves the measurement of carefully chosen single and double polarisation observables. In a joint endeavour by MAMI, ELSA, and Jefferson Laboratory, a new generation of experiments with polarised beams, polarised proton and neutron targets, and 4π particle detectors have been performed in recent years. Many results of unprecedented quality were recently published by all three experiments, and included by the various partial wave analysis groups in their analyses, leading to substantial improvements, e.g. a more precise determination of resonance parameters. An overview of recent results is given, with an emphasis on results from the CBELSA/TAPS experiment, and their impact on our understanding of the nucleon excitation spectrum is discussed.

  9. Photoproduction and Photodisintigration Processes of the Deuteron

    NASA Astrophysics Data System (ADS)

    Gohs, Jessica; Briscoe, William; Hornidge, Dave; Moores, Korwin; McDermit, Kevin; Bulmer, Kris; Patterson, Steven; Starotsin, Sasha; Rost, Mattias; Downie, Eve

    2004-10-01

    The Mainz Mictrotron (MAMI) is a continuous wave electron accelerator located at the Institut fuer Kernphysik in Mainz, Germany. It is the best tagged photon facility below 855 MeV and has extremely high energy resolution. TAPS, or Two Arm Photon Spectrometer, is a high resolution photon detection system that has been used at MAMI for the past fifteen years. In 2002 the (SLAC) Crystal Ball multiphoton spectrometer was moved from Brookhaven National Laboratory to Mainz due to the excellent facilities at MAMI. The combination of TAPS and the Crystal Ball form a truly 4p detection system for protons and neutrons. A photon beam with energies between 400 and 855 MeV has been used with a liquid deuterium target to investigate several photoproduction and photodisintigration processes. Among these are coherent p0 production on the deuteron itself, p0 production off the individual quasi-free nucleons, and the photodisintigration of the deuteron into a proton and a neutron. While each of these processes have physics interest, the latter can also be used to calibrate the detection efficiency of the Crystal Ball and TAPS for neutrons. We plan to report on the preliminary physics and calibration results from the first measurements made with the deuterium target.

  10. Photoproduction of η and η' Mesons on Proton

    NASA Astrophysics Data System (ADS)

    Kashevarov, V. L.; Tiator, L.; Ostrick, M.

    New high-precision total and differential cross sections for η and η' photoproduction on the proton obtained by the A2 Collaboration at the Mainz Microtron are presented. The data for η photoproduction demonstrate a cusp at the energy W ˜ 1.9 GeV. Furthermore, we present a new version of the ηMAID model for η and η' photoproduction. The model includes 23 nucleon resonances parametrized with Breit-Wigner shapes. The background is described by vector and axial-vector meson exchanges in the t channel using the Regge phenomenology. Parameters of the resonances were obtained from a fit to preliminary data of the A2 Collaboration at MAMI and available data from other collaborations. The cusp is explained as a threshold effect due to the opening η'p decay channel of the N(1895)1/2- resonance.

  11. 34 CFR 6.4 - Central records; confidentiality.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Education Office of the Secretary, Department of Education INVENTIONS AND PATENTS (GENERAL) § 6.4 Central records; confidentiality. Central files and records shall be maintained of all inventions, patents, and... Department under such patents. Invention reports required from employees or others for the purpose...

  12. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... potential of military resale commodities. (4) Establish policies and procedures which reserve to its agency... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military...

  13. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale commodities are available from the central nonprofit agencies. Authorized resale outlets (military...

  14. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale commodities are available from the central nonprofit agencies. Authorized resale outlets (military...

  15. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale commodities are available from the central nonprofit agencies. Authorized resale outlets (military...

  16. 41 CFR 51-6.4 - Military resale commodities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Military resale... PROCEDURES § 51-6.4 Military resale commodities. (a) Purchase procedures for ordering military resale commodities are available from the central nonprofit agencies. Authorized resale outlets (military...

  17. Spore Photoproduct Lyase: The Known, the Controversial, and the Unknown*

    PubMed Central

    Yang, Linlin; Li, Lei

    2015-01-01

    Spore photoproduct lyase (SPL) repairs 5-thyminyl-5,6-dihydrothymine, a thymine dimer that is also called the spore photoproduct (SP), in germinating endospores. SPL is a radical S-adenosylmethionine (SAM) enzyme, utilizing the 5′-deoxyadenosyl radical generated by SAM reductive cleavage reaction to revert SP to two thymine residues. Here we review the current progress in SPL mechanistic studies. Protein radicals are known to be involved in SPL catalysis; however, how these radicals are quenched to close the catalytic cycle is under debate. PMID:25477522

  18. Laser shock peening of titanium 6-4 alloy

    NASA Astrophysics Data System (ADS)

    Brar, N. S.; Hopkins, A.; Laber, M. W.

    2000-04-01

    Laser shock peening of titanium 6-4 has been shown to improve its high cycle fatigue life. Residual compressive stresses generated on the surface of titanium 6-4, as a result of laser shocking, have shown dramatic improvement in the performance of aircraft turbine blades. Laser shocking of titanium was carried out with a 20 ns pulse width, 50 joule pulsed laser, operated by LSP Technologies, Columbus, OH. Titanium disks, 20-mm in diameter, and ranging in thicknesses from zero (bare LiF) to 3-mm were subjected to laser shock to monitor amplitude and temporal stress profiles of the pulsed laser. Laser shock stress amplitudes on the back of titanium disks were monitored with VISAR using LiF as the window material. The peak shock stress produced in LiF (titanium thickness zero) was measured to be 16±1 GPa. The laser shock amplitude decays to about 2.7 GPa while propagating through 3-mm thick disk of titanium 6-4.

  19. Laser Shock Peening of Titanium 6-4 Alloy

    NASA Astrophysics Data System (ADS)

    Hopkins, Alan; Laber, Mark; Brar, Nachhatter S.

    1999-06-01

    shock 99 Laser shock peening of titanium 6-4 has been shown to improve its high cycle fatigue life. Residual compressive stresses generated on the surface of titanium 6-4, as a result of laser shocking, have shown dramatic improvement in the performance of aircraft turbine blades. Laser shocking of titanium was carried out with a 20 ns pulse width, 50 joule pulsed laser, operated by LSP Technologies, Columbus, OH. Disks of titanium, 0 to 3-mm thick and 20-mm in diameter, were subjected to the pulsed laser to monitor amplitude and temporal stress profiles of laser shock. Laser shock stress amplitudes on the back of titanium disks were monitored with VISAR using LiF as the window material. The peak shock stress produced in LiF (titanium thickness zero) was measured to be 16±1 GPa. The laser shock amplitude decays to about 2.6 GPa while propagating through 3-mm thick disk of titanium 6-4. *Supported by the U.S. Air Force Research Laboratory

  20. Note on the photoproduction of the charged A1

    NASA Astrophysics Data System (ADS)

    Condo, G. T.; Handler, T.

    1987-05-01

    Arguments made nearly 15 years ago by Fox and Hey are updated in the light of recent experimental findings. These indicate that the charge-exchange photoproduction of the A1 should dominate that of the A2. Consistency with the experimental data demands an A1 mass of 1335+/-20 MeV and width of 180+/-55 MeV.

  1. Nucleon resonances: From photoproduction to high photon virtualities

    SciTech Connect

    Gothe, Ralf W.; Mokeev, Viktor; Santopinto, Elena

    2016-09-22

    Here, the topical workshop “Nucleon Resonances: From Photoproduction to High Photon Virtualities” took place at the European Center for Theoretical Studies in Nuclear Physics and Related Areas in Trento, Italy from October 12–16, 2015. The organizing committee consisted of R.W. Gothe (Chair, USC), V.I. Mokeev (Jefferson Lab), and E. Santopinto (INFN).

  2. Coupled-channel analysis for ϕ photoproduction with Λ(1520)

    NASA Astrophysics Data System (ADS)

    Ozaki, S.; Hosaka, A.; Nagahiro, H.; Scholten, O.

    2009-09-01

    We investigate photoproduction of ϕ mesons off protons within a coupled-channel effective-Lagrangian method which is based on the K-matrix approach. Since the threshold energy of the KΛ(1520) channel is close to that of ϕN, the contribution of this channel to ϕ photoproduction near the threshold energy region may give rise to some unexpected structures. In the transition amplitude KΛ(1520)→ϕN, the kinematics allows an intermediate kaon to be on-shell. This happens in the energy region where a peak structure has been observed in ϕ photoproduction. In our calculations, the on-shell kaon effect indeed reproduces a peak structure, though with a magnitude that is far too small to explain the observed effect. As a following step, we introduce a nucleon resonance in our model. The coupling of the resonance to the KΛ(1520) and ϕN channels is not suppressed by the Okubo-Zweig-Iizuka (OZI) rule if the resonance contains a dominant hidden strangeness component. We find that the resonance can reproduce a peak structure of the correct magnitude at the right energy. We also investigate the effects of coupled channels and the resonance on the angular distribution and the spin-density matrices for ϕ photoproduction.

  3. Diffractive vector meson photoproduction from dual string theory

    SciTech Connect

    Freund, Peter G. O.; Nastase, Horatiu

    2009-04-15

    We study diffractive vector-meson photoproduction using string theory via AdS/CFT. The large s behavior of the cross sections for the scattering of the vector meson V on a proton is dominated by the soft Pomeron, {sigma}{sub V}{approx}s{sup 2{epsilon}}{sup -2{alpha}{sub P}{sup '}}{sup /B}, where from the string theory model of [arXiv:hep-th/0501039], {epsilon} is approximately 1/7 below 10 GeV, and 1/11 for higher, but still sub-Froissart, energies. This is due to the production of black holes in the dual gravity. In {phi} photoproduction the mesonic Regge poles do not contribute, so that we deal with a pure Pomeron contribution. This allows for an experimental test. At the gauge theory 'Planck scale' of about 1-2 GeV, the ratios of the soft Pomeron contributions to the photoproduction cross sections of different vector mesons involve not only the obvious quark model factors, but also the Boltzmann factors e{sup -4M{}sub V}{sup /T{}sub 0}, with T{sub 0} the temperature of the dual black hole. The presence of these factors is confirmed in the experimental data for {rho}, {omega}, {phi}, J/{psi}, and {psi}(2S) photoproduction and is compatible with the meager {upsilon} photoproduction data. Throughout, we use vector-meson dominance, and from the data we obtain T{sub 0} of about 1.3 GeV, i.e. the gauge theory ''Planck scale,'' as expected. The ratio of the experimental soft Pomeron onset scale E-circumflex{sub R}{approx}9 GeV and of the gauge theory Planck scale, T{sub 0}{approx}1.3 GeV, conforms to the theoretical prediction of N{sub c}{sup 2}/N{sub c}{sup 1/4}.

  4. The g-tensor of the flavin cofactor in (6-4) photolyase: a 360 GHz/12.8 T electron paramagnetic resonance study

    NASA Astrophysics Data System (ADS)

    Schnegg, A.; Kay, C. W. M.; Schleicher, E.; Hitomi, K.; Todo, T.; Möbius, K.; Weber, S.

    2006-05-01

    The g-tensor of the neutral radical form of the flavin adenine dinucleotide cofactor FADH• of (6-4) photolyase from Xenopus laevis has been determined by very high-magnetic-field/high-microwave-frequency electron-paramagnetic resonance (EPR) performed at 360 GHz/12.8 T. Due to the high spectral resolution the anisotropy of the g-tensor could be fully resolved in the frozen-solution continuous-wave EPR spectrum. By least square fittings of spectral simulations to experimental data, the principal values of the g-tensor have been established: gX = 2.00433(5), gY = 2.00368(5), gZ = 2.00218(7). A comparison of very high-field EPR data and proton and deuteron electron-nuclear double resonance measurements yielded precise information concerning the orientation of the g-tensor with respect to the molecular frame. This data allowed a comparison to be made between the principal values of the g-tensors of the FADH• cofactors of photolyases involved in the repair of two different DNA lesions: the cyclobutane pyrimidine dimer (CPD) and the (6-4) photoproduct. It was found that gX and gZ are similar in both enzymes, whereas the gY component is slightly larger in (6-4) photolyase. This result clearly shows the sensitivity of the g-tensor to subtle differences in the protein environment experienced by the flavin.

  5. Spin effects and baryon resonance dynamics in φ-meson photoproduction at few GeV

    NASA Astrophysics Data System (ADS)

    Titov, A. I.; Lee, T.-S. H.

    2003-06-01

    The diffractive φ-meson photoproduction amplitude is dominated by the Pomeron-exchange process and contains the terms that govern the spin-spin and spin-orbital interactions. We show that these terms are responsible for the spin-flip transitions at forward photoproduction angles and appear in the angular distributions of φ→K+K- decay in reactions with unpolarized and polarized photon beams. At large momentum transfers, the main contribution to the φ-meson photoproduction is found to be due to the excitation of nucleon resonances. Combined analysis of ω and φ photoproduction indicates strong Okubo-Zweig-Iizuka rule violation in φNN* couplings. We also show that the spin observables are sensitive to the dynamics of φ-meson photoproduction at large angles and could help to distinguish different theoretical models of nucleon resonances. Predictions for spin effects in φ-meson photoproduction are presented for future experimental tests.

  6. Photoproduction of η and η' mesons off protons

    NASA Astrophysics Data System (ADS)

    Crede, V.; McVeigh, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fuchs, M.; Funke, Chr.; Gothe, R.; Gregor, R.; Gridnev, A.; Gutz, E.; Höffgen, St.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Langheinrich, J.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Sparks, N.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.; Wilson, A.

    2009-11-01

    Total and differential cross sections for η and η'photoproduction off the proton have been determined with the CBELSA/TAPS detector for photon energies between 0.85 and 2.55 GeV. The η mesons are detected in their two neutral decay modes, η→γγ and η→3π0→6γ, and for the first time, cover the full angular range in cosθc.m. of the η meson. These new η photoproduction data are consistent with the earlier CB-ELSA results. The η' mesons are observed in their neutral decay to π0π0η→6γ and also extend the coverage in angular range.

  7. Pion photoproduction cross section at large momentum transfer

    SciTech Connect

    Sjoegren, Johan

    2015-02-27

    The Real Compton Scattering experiment was performed in Hall A at the Thomas Jefferson National Accelerator Facility. It was designed to measure, for Compton scattering and π0-photoproduction, the differential cross section over a range of kinematic points and the polarisation transfer to the proton at a single kinematic point. The full range of the experiment in Mandelstam variables t and s was 1.6-6.46 GeV2 and 4.82-10.92 GeV2 respectively with beam energies of 2-6 GeV. The motivation for the experiment is to test the cross section and polarisation transfer predictions of perturbative QCD versus that of predictions from Generalised Parton Distribution models. This thesis will give an overview of the pertinent theory, experimental setup in Hall A and the extracting of the π0-photoproduction cross section.

  8. Heavy quarkonium photoproduction in ultrarelativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Yu, Gong-Ming; Cai, Yang-Bing; Li, Yun-De; Wang, Jian-Song

    2017-01-01

    Based on the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD), we calculate the production cross section for the charmonium [J /ψ , ψ (2 S ) , χc J, ηc, and hc] and the bottomonium [Υ (n S ) , χb J, ηb, and hb] produced by the hard photoproduction processes and fragmentation processes in relativistic heavy ion collisions. It is shown that the existing experimental data on heavy quarkonium production at the Large Hadron Collider (LHC) can be described in the framework of the NRQCD formalism, and the phenomenological values of matrix elements for color-singlet and color-octet components give the main contribution. The numerical results of photoproduction processes and fragmentation processes for the heavy quarkonium production become prominent in p -p collisions and Pb-Pb collisions at LHC energies.

  9. Isolated Photons + Jets in DIS and Photoproduction at ZEUS

    NASA Astrophysics Data System (ADS)

    Kuprash, Oleg

    2013-12-01

    In this report, recent measurements of the production of isolated photons accompanied by jets in DIS and photo-production at HERA are presented. The measurements are compared to the perturbative QCD calculations and to the predictions made within the kT-factorisation QCD approach. A reasonable level of agreement between data and the predictions of both types is observed, however there is still room for the theories to be improved.

  10. Phototransformation of Amlodipine: Degradation Kinetics and Identification of Its Photoproducts

    PubMed Central

    Jakimska, Anna; Śliwka-Kaszyńska, Magdalena; Nagórski, Piotr; Namieśnik, Jacek; Kot-Wasik, Agata

    2014-01-01

    Nowadays, monitoring focuses on the primary compounds and does not include degradation products formed during various biological and chemical processes. Transformation products may have the same effects to human health and the environment or sometimes they can be more toxic than the parent compound. Unfortunately, knowledge about the formation of degradation products is still limited, however, can be very important for the environmental risk assessment. Firstly, the photodegradation kinetic of amlodipine was investigated in two experimental conditions: during the exposure to solar radiation and during the exposure to the light emitted by the xenon lamp. In all cases degradation of amlodipine followed a pseudo-first-order kinetics. In the next step, identification of transformation products of amlodipine formed during the exposure to xenon lamp irradiation was performed using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). As a result sixteen photoproducts were identified, their structures were elucidated and ultimately the transformation pathway was proposed. Fifteen compounds (out of 16 photoproducts) were newly identified and reported here for the first time; some of those compounds were formed from the first photoproduct, amlodipine pyridine derivative. Several analytes were formed only in acidic or basic conditions. Furthermore, the occurrence of amlodipine and its identified degradation products was investigated in environmental waters. Only one out of 16 compounds was found in wastewater effluent. The possibility of the sorption of examined analytes to sewage sludge particles was discussed based on QSAR. PMID:25279815

  11. The relative roles of DNA damage induced by UVA irradiation in human cells.

    PubMed

    Cortat, Barbara; Garcia, Camila Carrião Machado; Quinet, Annabel; Schuch, André Passaglia; de Lima-Bessa, Keronninn Moreno; Menck, Carlos Frederico Martins

    2013-08-01

    UVA light (320-400 nm) represents approximately 95% of the total solar UV radiation that reaches the Earth's surface. UVA light induces oxidative stress and the formation of DNA photoproducts in skin cells. These photoproducts such as pyrimidine dimers (cyclobutane pyrimidine dimers, CPDs, and pyrimidine (6-4) pyrimidone photoproducts, 6-4PPs) are removed by nucleotide excision repair (NER). In this repair pathway, the XPA protein is recruited to the damage removal site; therefore, cells deficient in this protein are unable to repair the photoproducts. The aim of this study was to investigate the involvement of oxidative stress and the formation of DNA photoproducts in UVA-induced cell death. In fact, similar levels of oxidative stress and oxidised bases were detected in XP-A and NER-proficient cells exposed to UVA light. Interestingly, CPDs were detected in both cell lines; however, 6-4PPs were detected only in DNA repair-deficient cells. XP-A cells were also observed to be significantly more sensitive to UVA light compared to NER-proficient cells, with an increased induction of apoptosis, while necrosis was similarly observed in both cell lines. The induction of apoptosis and necrosis in XP-A cells using adenovirus-mediated transduction of specific photolyases was investigated and we confirm that both types of photoproducts are the primary lesions responsible for inducing cell death in XP-A cells and may trigger the skin-damaging effects of UVA light, particularly skin ageing and carcinogenesis.

  12. Recent results on eta and eta-prime photoproduction on the proton

    SciTech Connect

    Barry Ritchie

    2004-06-01

    The experimental situation on eta and eta' photoproduction on the proton is reviewed, emphasizing progress made since 2001. New preliminary results for eta' photoproduction on the proton from Jefferson Lab are presented. Experimental results are compared with several theoretical approaches, with an emphasis on consequences for understanding baryon spectroscopy.

  13. Theoretical estimates of photoproduction cross sections for neutral subthreshold pions in carbon-carbon collisions.

    PubMed

    Norbury, J W; Townsend, L W

    1986-01-01

    Using the Weizsacher-Williams method of virtual quanta, total cross section estimates for the photoproduction of neutral subthreshold pions in carbon-carbon collisions at incident energies below 300 MeV/nucleon are made. Comparisons with recent experimental data indicate that the photoproduction mechanism makes an insignificant contribution to these measured cross sections.

  14. UV-induced photoproducts of 5-methylcytosine in a DNA sequence context.

    PubMed Central

    Barna, T; Malinowski, J; Holton, P; Ruchirawat, M; Becker, F F; Lapeyre, J N

    1988-01-01

    In order to detect possible m5C photoproducts, highly purified rat liver DNA-cytosine methyltransferase was used to specifically generate m5C with a radioactive methyl group. When these DNAs were subjected to a large dose (10 kJ/m2) of 254 nm or 302 nm ultraviolet light (UVB) to enhance the yield, two labeled photoproducts were detected and isolated by reverse phase HPLC after formic acid hydrolysis. Further studies using acetone as a triplet state sensitizer and UVB irradiation suggested that photoproduct II was activated via a triplet state while the more polar photoproduct I was not. Photoreversion of the purified photoproducts with 10 kJ/m2 254 nm light demonstrated the following reactions: Photoproduct I regenerated m5C, while photoproduct II is split and regenerated m5C and photoproduct I. These results suggest that photoproduct I is monomeric while photoproduct II dimeric, and from the latter's elution position possibly a cyclobutyl type dimer arising from a reaction with an adjacent cytosine. Using d[TTG] and d[Cm5CG] as models of typical sequences, irradiation with 10 kJ/m2 254 nm or 302 nm, respectively, gave rise to a small component having altered mobility in sequencing gels. The altered mobility trinucleotides were resistant to degradation by PI and micrococcal nucleases as expected from photodimerization of the pyrimidine bases. Furthermore, oligonucleotide substrates containing m5C were synthesized and shown to be susceptible to T4 endonuclease v action at locations consistent with d[Cm5C] photodimer formation when irradiated in the UVB range. Images PMID:3375057

  15. Ultraviolet-induced mutations in Cockayne syndrome cells are primarily caused by cyclobutane dimer photoproducts while repair of other photoproducts is normal

    SciTech Connect

    Parris, C.N.; Kraemer, K.H. )

    1993-08-01

    The authors compared the contribution to mutagenesis on Cockayne syndrome (CS) cells of the major class of UV photoproducts, the cyclobutane pyrimidine dimer, to that of other DNA photoproducts by using the mutagenesis shuttle vector pZ189. Lymphoblastoid cell lines from the DNA repair-deficient disorders CS and xeroderma pigmentosum (XP) and a normal line were transfected with UV-treated pZ189. Cyclobutane dimers were selectively removed before transfection by photoreactivation (PR), leaving nondimer photoproducts intact. After UV exposure and replication in CS and XP cells, plasmid survival was abnormally elevated. After PR, plasmid survival increased and mutation frequency in CS cells decreased to normal levels but remained abnormal in XP cells. Sequence analysis of >200 mutant plasmids showed that with CS cells a major mutational hot spot was caused by unrepaired cyclobutane dimers. These data indicate that with both CS and XP cyclobutane dimers are major photoproducts generating reduced plasmid survival and increased mutation frequency. However, unlike XP, CS cells are proficient in repair of nondimer photoproducts. Since XP but not CS patients have a high frequency of UV-induced skin cancers, the data suggest that prevention of UV-induced skin cancers is associated with proficient repair of nondimer photoproducts. 38 refs., 3 figs., 2 tabs.

  16. Photoproduction of the Bc(*) meson at the LHeC

    NASA Astrophysics Data System (ADS)

    Bi, Huan-Yu; Zhang, Ren-You; Han, Hua-Yong; Jiang, Yi; Wu, Xing-Gang

    2017-02-01

    We make a detailed study of the photoproduction mechanism of the doubly heavy flavored Bc(*) meson at the purposed Large Hadron Electron Collider (LHeC) within the framework of nonrelativistic QCD. In addition to the photoproduction mechanism via the gluon-induced channel γ +g →Bc(*)+b +c ¯ , the extrinsic heavy quark mechanism via the two channels γ +c →Bc(*)+b and γ +b ¯ →Bc(*)+c ¯ has also been studied. Those two extrinsic channels are generally suppressed by the heavy quark distribution functions in the proton, which provide significant contributions in the low and intermediate pT region. A detailed comparison of those channels together with the theoretical uncertainties has been presented. By summing up all the mentioned photoproduction channels, we observe that about (1.0 4-0.53+0.90)×1 05 Bc and (4.8 6-2.30+3.72)×1 05 Bc* events can be generated at the LHeC in one operation year with the proton-electron collision energy √{S }=1.30 TeV and the luminosity L ≃1 033 cm-2 s-1 . Here the errors are for mc=1.50 ±0.20 and mb=4.9 ±0.40 GeV . Thus, in addition to the hadronic experiments, the LHeC shall provide another helpful platform for studying the Bc(*) meson properties, especially to test the extrinsic heavy quark mechanism.

  17. Photoproduction of ω mesons on nuclei near the production threshold

    NASA Astrophysics Data System (ADS)

    Nanova, M.; Weil, J.; Friedrich, S.; Metag, V.; Mosel, U.; Thiel, M.; Anton, G.; Bacelar, J. C. S.; Bartholomy, O.; Bayadilov, D.; Beloglazov, Y. A.; Bogendörfer, R.; Castelijns, R.; Crede, V.; Dutz, H.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fuchs, M.; Funke, Ch.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Hössl, J.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kopf, B.; Kotulla, M.; Krusche, B.; Langheinrich, J.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Morales, C.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Radkov, A.; Schadmand, S.; Schmidt, Ch.; Schmieden, H.; Schoch, B.; Shende, S.; Suft, G.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.

    2011-02-01

    The photoproduction of ω mesons on LH2 , C and Nb has been measured for incident photon energies from 900 to 1300MeV using the CB/TAPS detector at ELSA. The ω lineshape does not show any significant difference between the LH2 and the Nb targets. The experiment was motivated by transport calculations that predicted a sensitivity of the ω lineshape to in-medium modifications near the production threshold on a free nucleon of E_{γ^{lab}=1109} MeV. A comparison with recent calculations is given.

  18. Quasifree Photoproduction of η Mesons off the Neutron

    NASA Astrophysics Data System (ADS)

    Jaegle, I.; Mertens, T.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fuchs, M.; Funke, Ch.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Lang, M.; Langheinrich, J.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Messchendorp, J. G.; Metag, V.; Morales, C.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Radkov, A.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.

    2008-06-01

    Quasifree photoproduction of η mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The η mesons have been detected in coincidence with recoil protons and recoil neutrons, which allows a detailed comparison of the quasifree n(γ,η)n and p(γ,η)p reactions. The excitation function for η production off the neutron shows a pronounced bumplike structure at W=1.68GeV (Eγ≈1GeV), which is absent for the proton.

  19. Quasifree photoproduction of eta mesons off the neutron.

    PubMed

    Jaegle, I; Mertens, T; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D; Beck, R; Beloglazov, Y A; Castelijns, R; Crede, V; Dutz, H; Ehmanns, A; Elsner, D; Essig, K; Ewald, R; Fabry, I; Fuchs, M; Funke, Ch; Gothe, R; Gregor, R; Gridnev, A B; Gutz, E; Höffgen, S; Hoffmeister, P; Horn, I; Junkersfeld, J; Kalinowsky, H; Kammer, S; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Konrad, M; Kotulla, M; Krusche, B; Lang, M; Langheinrich, J; Löhner, H; Lopatin, I V; Lotz, J; Lugert, S; Menze, D; Messchendorp, J G; Metag, V; Morales, C; Nanova, M; Nikonov, V A; Novinski, D; Novotny, R; Ostrick, M; Pant, L M; van Pee, H; Pfeiffer, M; Radkov, A; Roy, A; Sarantsev, A V; Schadmand, S; Schmidt, C; Schmieden, H; Schoch, B; Shende, S V; Sokhoyan, V; Süle, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Weinheimer, Ch; Wendel, Ch

    2008-06-27

    Quasifree photoproduction of eta mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The eta mesons have been detected in coincidence with recoil protons and recoil neutrons, which allows a detailed comparison of the quasifree n(gamma,eta)n and p(gamma,eta)p reactions. The excitation function for eta production off the neutron shows a pronounced bumplike structure at W=1.68 GeV (E{gamma} approximately 1 GeV), which is absent for the proton.

  20. Recent N* results from photoproduction experiments at CLAS

    SciTech Connect

    D. Sokhan

    2011-10-01

    The recent breakthroughs in the technology of polarized targets have enabled a new generation of meson photo-production experiments to be carried out. A measurement of a full set of polarization observables off both polarized proton and neutron tar gets and in a large number of meson-production channels has come within sight. Such a measurement would very significantly reduce model-dependence in the analysis of the data and thus has the potential to resolve long-standing issues, such as the 'missing resonance' problem, and shed new light on the nucleon excitation spectrum. This has formed the motivation for the recent N* experimental programme of CLAS.

  1. Heavy quark photoproduction in coherent interactions at high energies

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Machado, M. V. T.; Meneses, A. R.

    2009-08-01

    We calculate the inclusive and diffractive photoproduction of heavy quarks in proton-proton collisions at Tevatron and CERN LHC energies, where the photon reaches energies larger than those ones accessible at DESY-HERA. The integrated cross section and the rapidity distributions for charm and bottom production are computed within the color dipole picture employing three phenomenological saturation models based on the color glass condensate formalism. Our results demonstrate that the experimental analyses of these reactions are feasible and that the cross sections are sensitive to the underlying parton dynamics.

  2. APOLLON at DESY: Spin-dependent photoproduction of charm

    SciTech Connect

    Miller, C. A.

    1998-01-20

    APOLLON is a proposal to measure the polarization asymmetry of J/{psi} photoproduction in a fixed target experiment at HERA in an effort to provide information on the gluon spin distribution in the nucleon. Inelastic production will be identified via the {mu}{sup +}{mu}{sup -} decay channel, resulting in a statistical precision of {delta}A=0.05 in a 12 month run. In the LO CSM, the corresponding precision in {delta}G(x)/G(x) is 0.15 at x{approx}0.4.

  3. Photoproduction and Decay of Light Mesons in CLAS

    SciTech Connect

    Amaryan, Moskov Jamalovich

    2013-08-01

    We present preliminary experimental results on photoproduction and decay of light mesons measured with CLAS setup at JLAB . This include Dalitz decay of pseudoscalar and vector mesons, radiative decay of pseudoscalar mesons as well hadronic decays of pseudoscalar and vector mesons. The collected high statistics in some of decay channels exceeds the world data by an order of magnitude and some other decay modes are observed for the first time. It is shown how the CLAS data will improve the world data on transition form factors of light mesons, Dalitz plot analyses, branching ratios of rare decay modes and other fundamental properties potentially accessible through the light meson decays.

  4. Measurement of heavy-quark jet photoproduction at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bołd, T.; Bolilyi, O.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; Del Peso, J.; Dementiev, R. K.; de Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Fourletov, S.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bołd, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.-P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kooijman, P.; Korol, I.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kowalski, H.; Kulinski, P.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Łużniak, P.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nicholass, D.; Nigro, A.; Ning, Y.; Nobe, T.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycień, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Ron, E.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Uribe-Estrada, C.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Whyte, J.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zhou, C.; Zichichi, A.; Zolko, M.; Zotkin, D. S.; Zulkapli, Z.

    2011-05-01

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb-1. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, pT^{jet}, and pseudorapidity, η jet, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions.

  5. Photoproduction de Mesons sur le Nucleon aux Energies Intermediaire (in French) [Photoproduction of mesons on the nucleon at intermediate energies

    SciTech Connect

    Guidal, Michel

    1996-12-13

    One object of this thesis is to propose a model taking account of low transfer reaction mechanisms for a series of photoproduction reactions on nucleons for photon energies ≳4 GeV. If our comprehension of processes with low transfers is correct, then extrapolating our model in the domain of large transfers and the comparison with data supplied will give us information on the domains in energy and transfers from which an interpretation of reactions in terms of the "soft" process ceases to be valid. In the domain of large transfers, only one approach in terms of "hard" process can then explain the data. We are interested in electromagnetic photoproduction reactions because the probe, firstly, interacts with the target via an exact and well known mechanism (described by the QED theory) and also eliminates the interaction phenomena in the initial state. No probe is as well known as the photon. The extraction of reaction mechanisms, amplitudes and coupling constants match is made easier than in the case of hadronic probes. The energy domain Eγ >4 GeV studied is particularly interesting because it is from this energy of incident photons that can be expected to achieve large enough pulse transfers to hope for emergence of hard processes and therefore see the cessation of validity of interpretation of hadron models. Also, resonance effects are minor and do not interfere with our interpretations. Experimentally, this area is widely unexplored and the new generation accelerators of a large duty cycle (CEBAF, MAMI, ESRF, ELF, ...) combined with 4π detectors will allow to precisely measure low cross sections reactions of a large transfer. We first study pion photoproduction reactions on nucleon because they are the most experimentally accessible reactions and many data of high energy and low transfers exist. This will require strong constraints on the model parameters of the numerous analyses performed previously. Then we'll move on to kaon photoproduction

  6. Eta(547) and Eta(958) Meson Photoproduction on the Proton

    SciTech Connect

    Dugger, Michael

    2001-12-01

    Photoproduction of η and η' mesons has been studied at the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) using a tagged photon beam incident on a hydrogen target with photon energies from the respective production thresholds up to 2.4 GeV. The photoproduced mesons were identified via missing mass reconstruction using recoil proton momentum and time of flight information. Data were obtained in a range of √s from threshold to 2.2 GeV for each meson. In this study, differential cross-section measurements for the γp →pη and γp → pη' reactions are presented, and the results compared to recent data. An isobar analysis of the differential cross-sections is performed. The predicted differential cross-sections from the isobar analysis are used to predict behavior in unmeasured regions of phase space, and to infer total cross sections. For the γp → pη reaction, a value of the S11(1535) proton helicity amplitude also was extracted and compared to recent analyses. The data presented greatly extends the energy and angle coverage for differential cross-sections of η photoproduction, and significantly improves the accuracy with which η' cross sections are known.

  7. Photoproduction of ω mesons off nuclei and impact of polarization on the meson-nucleon interaction

    DOE PAGES

    Chudakov, Eugene A.; Gevorkyan, Sergey; Somov, Alexander

    2016-01-25

    We consider photoproduction of ω mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons σT = σ(VTN) can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the not-yet-measured total cross section for longitudinally polarized mesons σL = σ(VLN). The predictions for the latter strongly depend on the theoretical approaches. Furthermore, this work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designedmore » to study the photoproduction of mesons in a large beam energy range up to 12 GeV.« less

  8. Exclusive photoproduction of quarkonium at the LHC energies within the color dipole approach

    SciTech Connect

    Ducati, M. B. Gay; Griep, M. T.; Machado, M. V. T.

    2015-04-10

    The exclusive photoproduction of ψ(2S) meson was investigated and the coherent and the incoherent contributions were evaluated. The light-cone dipole formalism was considered in this analysis and predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV. A comparison is done to the recent ALICE Collaboration data for the ψ(1S) state photoproduction with good agreement.

  9. Unitary constraints on charged pion photoproduction at large p⊥

    SciTech Connect

    Laget, Jean-Marc

    2010-01-25

    Around $\\theta_{\\pi}=$90$^\\circ$, the coupling to the $\\rho^\\circ N$ channel leads to a good accounting of the charged pion exclusive photoproduction cross section in the energy range 3 < Eγ < 10 GeV, where experimental data exist. Starting from a Regge Pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment provides an explanation of the $s^{-7}$ scaling of the cross section. Furthermore, elastic rescattering of the charged pion improves the basic Regge pole model at forward and backward angles.

  10. Baryon Antibaryon Photoproduction using CLAS at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Phelps, William; CLAS Collaboration

    2014-09-01

    There is little known about the baryon antibaryon photoproduction mechanism. Three reactions, γ p --> pp p , γp --> pp π- n , and γp --> p p π+ n have been investigated for the photon energy range of 4.4-5.45 GeV. The data were from the g12 experiment taken with the CLAS detector using a liquid hydrogen target at Thomas Jefferson National Accelerator Facility. This experiment had high statistics, with an integrated luminosity of 68 pb-1. General features of the data for these three reactions will be shown. In particular, the angular and energy dependence of the antibaryons as well as the preliminary normalized yields will be presented. Also, preliminary partial wave analysis results for the p p system will be discussed.

  11. Baryon Antibaryon Photoproduction using CLAS at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Phelps, William

    2015-04-01

    There is little known about the baryon antibaryon photoproduction mechanism. Three reactions, γp --> pp p , γp --> ppπ- n , and γp --> p p π+ n have been investigated for the photon energy range of 4.4-5.45 GeV. The data were from the g12 experiment taken with the CLAS detector using a liquid hydrogen target at Thomas Jefferson National Accelerator Facility. This experiment had high statistics, with an integrated luminosity of 68 pb-1. General features of the data for these three reactions will be shown. In particular, the angular and energy dependence of the antibaryons as well as the preliminary normalized yields will be presented. Also, preliminary partial wave analysis results for the p p system will be discussed.

  12. Charmed meson lifetimes from 20 GeV photoproduction

    SciTech Connect

    Brau, J.E.

    1985-01-01

    A sample of 134 events containing 159 visible multiprong charm decays has been obtained from the 20 GeV charm photoproduction experiment at the SLAC Hybrid Facility. Following a selection procedure which ensures high and uniform detection efficiency for selected events, 47 charged, 46 neutral and five topologically ambiguous decays remain. These decays yield preliminary lifetimes of ..pi../sub D/sup +-// = (9.2 +- 1.5 +- 0.5) x 10/sup -13/ secs ..pi../sub D//sup 0/ approx. = (6.1 +- 1.1 +- 0.4) x 10/sup -13/ secs and a ratio (phi/sub D/sup +-//)/(tau/sub D/sup 0//) = 1.5/sub -0.3//sup +0.6/ +- 0.1. One fully reconstructed four-body D/sup 0/ decay has a proper flight time of 55 x 10/sup -13/ seconds. 5 refs., 4 figs.

  13. Near-threshold photoproduction of Φ mesons from deuterium

    DOE PAGES

    Qian, X.; Chen, W.; Gao, H.; ...

    2011-01-05

    In this report, we measure the differential cross section onmore » $$\\phi$$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. Moreover, the extracted differential cross sections $$\\frac{d\\sigma}{dt}$$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Ultimately, this experiment establishes a baseline for a future experimental search for an exotic $$\\phi$$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $$\\phi$$ mesons.« less

  14. Are Hyperon Resonances Required in the Elementary K +Λ Photoproduction?

    NASA Astrophysics Data System (ADS)

    Mart, T.; Nurhadiansyah, N.

    2013-11-01

    We have investigated the role of hyperon resonances in the kaon photoproduction process, γ p → K +Λ, by using a covariant isobar model. To this end, new experimental data are used in the fitting process, whereas the old SAPHIR 1998 data are also used for comparison. The result indicates that the Λ(1600) P 01 and Λ(1810) P 01 hyperon resonances can significantly reduce the χ2 and, simultaneously, can increase the hadronic form factor cut-off in the background terms. This finding is different from the result of the previous studies, which showed that the Λ(1800) S 01 was important for this purpose, instead of the Λ(1600) P 01.

  15. Photoproduction of hydrogen by membranes of green photosynthetic bacteria

    SciTech Connect

    Bernstein, J D; Olson, J M

    1980-01-01

    Photoproduction of H/sub 2/ from ascorbate by unit-membrane vesicles from Chlorobium limicola f. thiosulfatophilum was achieved with a system containing gramicidin D, tetramethyl-p-phenylenediamine, methyl viologen, dithioerythritol, Clostridium hydrogenase, and an oxygen-scavenging mixture of glucose, glucose oxidase, ethanol, and catalase. Maximum quantum yield was less than one percent. Half maximum rate of H/sub 2/ production occurred at a white-light intensity of approximately 0.15 cm/sup -2/. The reaction was inhibited completely by 0.3% sodium dodecylbenzene sulfonate, 1% Triton X-100, or preheating the vesicles at 100/sup 0/C for 5 minutes. Low concentrations (0.01 and 0.05%) of Triton X-100 about doubled the reaction rate.

  16. Near-threshold photoproduction of Φ mesons from deuterium

    SciTech Connect

    Qian, X.; Chen, W.; Gao, H.; Hicks, K.; Kramer, K.; Laget, J. M.; Mibe, T.; Qiang, Y.; Stepanyan, S.; Tedeschi, D. J.; Xu, W.; Adhikari, K. P.; Amaryan, M.; Anghinolfi, M.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bellis, M.; Biselli, A. S.; Bookwalter, C.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Dey, B.; Dhamija, S.; Djalali, C.; Doughty, D.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Eugenio, P.; Fegan, S.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Jawalkar, S. S.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Konczykowski, P.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Martinez, D.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mikhailov, K.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, I.; Niroula, M. R.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Park, S.; Pereira, S. Anefalos; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, C. E.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Voutier, E.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

    2011-01-05

    In this report, we measure the differential cross section on $\\phi$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. Moreover, the extracted differential cross sections $\\frac{d\\sigma}{dt}$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Ultimately, this experiment establishes a baseline for a future experimental search for an exotic $\\phi$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $\\phi$ mesons.

  17. Photoproduction of η' mesons with the GlueX experiment

    NASA Astrophysics Data System (ADS)

    Kamel, Mahmoud; GlueX Collaboration Collaboration

    2017-01-01

    The GlueX experiment at Jefferson Lab studies the light meson spectrum and searches for hybrid and exotic mesons. In this experiment, a 9 GeV tagged, linearly polarized photon beam interacts with a liquid hydrogen target at the center of the GlueX detector. First results of the photo-production of η' mesons at beam energies ranging from 3.5 to 11 GeV will be presented. The η' have been identified through the decay channel η' ->π+π- γ , which has a large branching ratio of 29%. No data exist for beam energies above 6 GeV for this reaction. Supported by Jefferson Science Associates , LLC under U.S. DOE Contract NO. DE-AC05-06OR23177 and DESC0013620.

  18. Baryon Spectroscopy Through Partial-Wave Analysis and Meson Photoproduction

    SciTech Connect

    Manley, D. Mark

    2016-09-08

    The principal goal of this project is the experimental and phenomenological study of baryon spectroscopy. The PI's group consists of himself and three graduate students. This final report summarizes research activities by the PI's group during the period 03/01/2015 to 08/14/2016. During this period, the PI co-authored 11 published journal papers and one proceedings article and presented three invited talks. The PI's general interest is the investigation of the baryon resonance spectrum up to masses of ~ 2 GeV. More detail is given on two research projects: Neutral Kaon Photoproduction and Partial-Wave Analyses of γp → η p, γn → η n, and γp → K⁺ Λ.

  19. Search for new and unusual strangeonia in photoproduction using CLAS

    NASA Astrophysics Data System (ADS)

    Saini, Mukesh S.

    We perform a survey of the proton, K+, K - , - 3 charged track data, taken by the CLAS detector for the HyCLAS experiment [1] during the g12 run-period at Jefferson Lab. We aim to study the strong decay amplitudes, partial widths and production channels of strangeonia from the CLAS g12 dataset. HyCLAS was motivated by the experimental results for gluonic hybrid meson candidates, theoretical Lattice QCD, and Flux-tube Model calculations and predictions. The experiment was designed and conducted to search and observe new forms of hadronic matter through photoproduction. Crucial among the various channels explored in HyCLAS are those for strangeonia,resonances such as φ(1680), φ3(1850) and Y(2175) [2] decaying to φ eta. A meson decay via φ eta is the signature that unequivocally identifies a strangeonium (ss¯ ) state and is the main focus of this thesis. A strangeonium decay via φ eta is considered the premier decay mode to cleanly establish the strangeonia spectrum [3]. This is due to negligible interference of the φ eta decay mode with the non-strange nn¯ (n ∈ {u, d}) meson decay modes, on account of the fact that φ(1020) is an almost pure ss¯ vector meson and the eta meson possesses a strong component of ss¯ in it as well. Another analysis explored was the φ pio decay channel, which is an exotic decay mode for a meson. Decay of an initial ss¯ meson via this channel is forbidden on account of the conservation of isotopic spin whereas the decay of a nn¯ via the φ pi o decay mode is also forbidden by the Okubo - Zweig - Iizuka (OZI) rule. Thus, observation of a resonance decaying to φ pi o will provide strong evidence of mesons beyond qq¯, probably of a gluonic excitation - qq¯g or a tetraquark state - qq¯qq¯ [4]. A final state of proton, K + and K - is selected from the g12 dataset. An intermediate φ state is identified by its decay to K+ K-. Using Energy-Momentum conservation, missing mass in an event is calculated. Depending on the analyses

  20. Okubo-Zweig-Iizuka rule violation in photoproduction

    NASA Astrophysics Data System (ADS)

    Sibirtsev, A.; Meißner, Ulf-G.; Thomas, A. W.

    2005-05-01

    We investigate OZI rule violation in ω and ϕ-meson photoproduction off nucleons. Data on the total cross sections indicate a large ϕ/ω ratio of about 0.8 at the maximal available photon energy that is in good agreement with expectations from QCD. On the other hand, data at large four-momentum transfer exhibit a ratio of about 0.07, showing that the perturbative QCD regime is not approached at |t|>2 GeV2 and photon energies Eγ<4 GeV. The anomanously large ϕ/ω ratio at low energies, that is close to the reaction threshold, remains to be explained within nonperturbative QCD.

  1. Electro- and Photoproduction of Vector Mesons at Jefferson Lab

    SciTech Connect

    Marco Battaglieri

    2002-09-01

    The total and differential cross section for exclusive electro- and photoproduction of vector mesons in the resonance region and above (1.6 < W < 2.9 GeV) was measured at Jefferson Laboratory in a wide kinematic range (0 < Q2 < 4 GeV2 and 0< -t < 5 GeV2). The measurement of the total and differential cross section down to 100 pb/GeV2 with the full kinematic coverage, was possible for the first time thanks to the combination of the 100% duty cycle of CEBAF and the large acceptance of the CLAS detector. The main results from the CLAS Collaboration activity in this field will be presented and discussed.

  2. The FOREST detector for meson photoproduction experiments at ELPH

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J.; Kawano, A.; Kuwasaki, S.; Maeda, K.; Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y.; Sakamoto, Y.; Sato, M.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, S.; Tsuchikawa, Y.; Yamazaki, H.; Yonemura, H.

    2016-10-01

    An electromagnetic calorimeter complex, FOREST, has been constructed for meson photoproduction experiments at the Research Center for Electron Photon Science, Tohoku University. It consists of three types of calorimeters, which are made of pure cesium-iodide crystals, lead scintillating-fiber modules, and lead glass Cherenkov counters. Each calorimeter is equipped with a plastic scintillator hodoscope to identify charged particles. The design and performance of FOREST are described. The energy responses of test calorimeters have been investigated by using 100-800 MeV positron beams. The energy resolutions of the three calorimeters are found to be approximately 3%, 7%, and 5% for 1-GeV photons, respectively. A cryogenic hydrogen/deuterium target system fitted to the FOREST experiments and a newly developed data acquisition system are also presented.

  3. Rescattering in meson photoproduction from few body systems

    SciTech Connect

    J-M. Laget

    2006-04-01

    Exclusive reactions induced at high momentum transfer in few body systems provide us with an original way to study the production and propagation of hadrons in cold nuclear matter. In very well-defined parts of the phase space, the reaction amplitude develops a logarithmic singularity. It is on solid ground since it depends on only on-shell elementary amplitudes and on low momentum components of the nuclear wave function. This is the best window for studying the propagation of exotic configurations of hadrons such as the onset of color transparency. It may appear earlier in meson-photoproduction reactions, more particularly in the strange sector, than in the more classical quasi-elastic scattering of electrons. More generally, those reactions provide us with the best tool to determine the cross section of the scattering of various hadrons (strange particles, vector mesons) from the nucleon and to obtain the production of possible exotic states.

  4. Unitary constraints on charged pion photoproduction at large p⊥

    DOE PAGES

    Laget, Jean-Marc

    2010-01-25

    Aroundmore » $$\\theta_{\\pi}=$$90$$^\\circ$$, the coupling to the $$\\rho^\\circ N$$ channel leads to a good accounting of the charged pion exclusive photoproduction cross section in the energy range 3 < Eγ < 10 GeV, where experimental data exist. Starting from a Regge Pole approach that successfully describes vector meson production, the singular part of the corresponding box diagrams (where the intermediate vector meson-baryon pair propagates on-shell) is evaluated without any further assumptions (unitarity). Such a treatment provides an explanation of the $$s^{-7}$$ scaling of the cross section. Furthermore, elastic rescattering of the charged pion improves the basic Regge pole model at forward and backward angles.« less

  5. Measurement of charm fragmentation fractions in photoproduction at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Corso, F. Dal; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Iudin, A.; Jakob, H.-P.; Januschek, F.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Myronenko, V.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shevchenko, R.; Shimizu, S.; Shkola, O.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zakharchuk, N.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D. S.

    2013-09-01

    The production of D 0, D *+, D +, and charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb-1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the stangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum p T > 3 .8 GeV and pseudorapidity | η| < 1 .6. The charm fragmentation fractions are compared to previous results from HERA and from e + e - experiments. The data support the hypothesis that fragmentation is independent of the production process.

  6. Constituent-counting rule in photoproduction of hyperon resonances

    NASA Astrophysics Data System (ADS)

    Chang, Wen-Chen; Kumano, S.; Sekihara, Takayasu

    2016-02-01

    We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state Λ and Σ0 of the CLAS and SLAC-E84 collaborations, by considering a constituent-counting rule suggested by perturbative QCD. The counting rule emerges as a scaling behavior of cross sections in hard exclusive reactions with large scattering angles, and it enables us to determine the number of elementary constituents inside hadrons. Therefore, it could be used as a new method for identifying internal constituents of exotic hadron candidates. From the analyses of the γ p →K+Λ and K+Σ0 reactions, we find that the number of elementary constituents is consistent with nγ=1 , np=3 , nK+=2 , and nΛ=nΣ0=3 . Then, an analysis is made for the photoproductions of the hyperon resonances Λ (1405 ) , Σ (1385 )0 , and Λ (1520 ) , where Λ (1405 ) is considered to be a K ¯N molecule, and hence its constituent number could be 5. However, we find that the current data are not enough to conclude the numbers of their constituents. It is necessary to investigate the higher-energy region at √{s }>2.8 GeV experimentally beyond the energy of the available CLAS data to count the number of constituents clearly. We also mention that our results indicate energy dependence in the constituent number, especially for Λ (1405 ). If an excited hyperon is a mixture of three-quark and five-quark states, the energy dependence of the scaling behavior could be valuable for finding its composition and mixture.

  7. A Radical Transfer Pathway in Spore Photoproduct Lyase

    PubMed Central

    Yang, Linlin; Nelson, Renae S.; Benjdia, Alhosna; Lin, Gengjie; Telser, Joshua; Stoll, Stefan; Schlichting, Ilme; Li, Lei

    2013-01-01

    Spore photoproduct lyase (SPL) repairs a covalent UV-induced thymine dimer, spore photoproduct (SP), in germinating endospores and is responsible for endospores’ strong UV resistance. SPL is a radical SAM enzyme, which uses a [4Fe-4S]1+ cluster to reduce the S-adenosyl-L-methionine (SAM), generating a catalytic 5′-deoxyadenosyl radical (5′-dA•). This in turn abstracts an H atom from SP, generating an SP radical that undergoes β scission to form a repaired 5′-thymine and a 3′-thymine allylic radical. Recent biochemical and structural data suggest that a conserved cysteine donates an H atom to the thymine radical, resulting in a putative thiyl radical. Here we present structural and biochemical data which suggest that two conserved tyrosines are also critical in enzyme catalysis. One (Y99(Bs) in Bacillus subtilis SPL) is downstream of the cysteine, suggesting that SPL uses a novel hydrogen atom transfer (HAT) pathway with a pair of cysteine-tyrosine residues to regenerate SAM. The other tyrosine (Y97(Bs)) has a structural role to facilitate SAM binding; it may also contribute to the SAM regeneration process by interacting with the putative •Y99(Bs) and/or 5′-dA• intermediates to lower the energy barrier for the second H-abstraction step. Our results indicate that SPL is the first member of the radical SAM superfamily (comprising more than 44,000 members) to bear a catalytically operating HAT chain. PMID:23607538

  8. Photoproduction of scalar mesons using CLAS at JLab

    NASA Astrophysics Data System (ADS)

    Chandavar, Shloka; Hicks, Kenneth; Weygand, Dennis; CLAS Collaboration

    2014-09-01

    The search for glueballs has been ongoing for decades. The lightest glueball has been predicted by quenched lattice QCD to have a mass in the range of 1.0-1.7 GeV and JPC =0++ . The mixing of glueball states with neighbouring meson states complicates their identification. The f0 (1500) is one of several candidates for the lightest glueball, whose presence in the Ks0 Ks0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This is done by studying the reaction, γp -->fJ p -->Ks0> Ks0p --> 2 (π+π-) p using data from the g12 experiment. A brief description of this analysis, along with a preliminary partial wave analysis results will be presented. The search for glueballs has been ongoing for decades. The lightest glueball has been predicted by quenched lattice QCD to have a mass in the range of 1.0-1.7 GeV and JPC =0++ . The mixing of glueball states with neighbouring meson states complicates their identification. The f0 (1500) is one of several candidates for the lightest glueball, whose presence in the Ks0Ks0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This is done by studying the reaction, γp -->fJ p -->Ks0 Ks0p --> 2 (π+π-) p using data from the g12 experiment. A brief description of this analysis, along with a preliminary partial wave analysis results will be presented. NSF.

  9. Genetics of human sensitivity to ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Cleaver, James E.

    1994-07-01

    the major human health effects of solar and artificial UV light occur from the UVB and UVC wavelength ranges and involve a variety of short-term and long-term deleterious changes to the skin and eyes. the more important initial damage to cellular macromolecules involves dimerization of adjacent pyrimidines in DNA to produce cyclobutane pyrimidine dimes, (6-4) pyrimidine- pyrimidone, and (6-4) dewar photoproducts. these photoproducts can be repaired by a genetically regulated enzyme system (nucleotide excision repair) which removes oligonucleotides 29-30 nucleotides long that contain the photoproducts, and synthesizes replacement patches. At least a dozen gene products are involved in the process of recognizing photoproducts in DNA, altering local DNA helicity and cleaving the polynucleotide chain at defined positions either side of a photoproduct. Hereditary mutations in many of these genes are recognized in the human genetic disorders xeroderma pigmentosum (XP), Cockayne syndrome (CS), and trichothiodystrophy (TTD). Several of the gene products have other functions involving the regulation of gene transcription which accounts for the complex clinical presentation of repair deficient diseases that involve sensitivity of the skin and eyes to UV light, increased solar carcinogenesis (in XP), demyelination, and ganglial calcification (in CS), hair abnormalities (in TTD), and developmental and neurological abnormalities

  10. Photoproduction of the K+ K-(1750)

    SciTech Connect

    Mitchell, Ryan Edward

    2003-01-01

    While photoproduction has often been advertised as an important environment in which to study light meson spectroscopy, solid experimental results are sparse. In fact, beyond the relatively straightforward photoproduction of the ρ, ω, and Ψ mesons, the few results of exclusive photoproduction that do exist are poorly understood, and several, perhaps, have even been misinterpreted. After extensively reviewing the sometimes tenuous history of the exclusive photoproduction of the ''ρ1(1600)'', the ''ωπ0(1250)'', the ''ω(1650)'', and the ''K+K-(1750)'', new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K+K-(1750). This enhancement in low-pT K+K- pairs at a mass near 1750 MeV/c2 has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the JPC = 1-- ρ(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K+K-(1750), and based on precise measurements of its mass and width, and its absence from the K*K final state, the FOCUS data can finally render this interpretation implausible. In addition, several steps have been taken towards establishing a new interpretation. Based on limited angular analyses of its decay and the beam energy dependence of its production, they argue that, in the absence of any wild interference scenarios, the K+K-(1750) has JPC ≠ 1--, and, in fact, the most likely assignment appears to be 2++. It is hoped that this work can help set the stage for future reevaluations and new insights in photoproduction.

  11. 38 CFR 6.4 - Proof of age, relationship and marriage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., relationship and marriage. 6.4 Section 6.4 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS....4 Proof of age, relationship and marriage. Whenever it is necessary for a claimant to prove age, relationship or marriage, the provisions of 38 U.S.C. 103(c) and Part 3 this chapter will be followed....

  12. 38 CFR 6.4 - Proof of age, relationship and marriage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., relationship and marriage. 6.4 Section 6.4 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS....4 Proof of age, relationship and marriage. Whenever it is necessary for a claimant to prove age, relationship or marriage, the provisions of 38 U.S.C. 103(c) and Part 3 this chapter will be followed....

  13. 38 CFR 6.4 - Proof of age, relationship and marriage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Proof of age, relationship and marriage. 6.4 Section 6.4 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS....4 Proof of age, relationship and marriage. Whenever it is necessary for a claimant to prove...

  14. 38 CFR 6.4 - Proof of age, relationship and marriage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Proof of age, relationship and marriage. 6.4 Section 6.4 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS....4 Proof of age, relationship and marriage. Whenever it is necessary for a claimant to prove...

  15. 38 CFR 6.4 - Proof of age, relationship and marriage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Proof of age, relationship and marriage. 6.4 Section 6.4 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS....4 Proof of age, relationship and marriage. Whenever it is necessary for a claimant to prove...

  16. 12 CFR 6.4 - Capital measures and capital category definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Capital measures and capital category definitions. 6.4 Section 6.4 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY PROMPT... categories. For purposes of the provisions of section 38 and this part, a bank shall be deemed to be:...

  17. Photoproduction of carbonyl sulfide in south Pacific Ocean waters as a function of irradiation wavelength

    NASA Technical Reports Server (NTRS)

    Weiss, Peter S.; Andrews, Steven S.; Johnson, James E.; Zafiriou, Oliver C.

    1995-01-01

    Carbonly sulfide (OCS) photoproduction rates were measured at selected wavelengths of ultraviolet light between 297 and 405 nm in sea water samples from the southern Pacific Ocean. Near-surface and column production rate spectra for natural sunlit waters were calculated using sea-surface sunlight data measured near the austral summer solstice. These plots show that photoproduction rates are at a maximum at 313 nm in tropical waters and at 336 nm in Antarctic waters. Tropical surface and column rates were found to be 68 pM/day and 360 nmol/sq m/day, respectively, and Antarctic surface and column rates were found to be 101 pM/day and 620 nmol/sq m/day, respectively. A high degree of variability was observed between photoproduction rates from different ocean regions, with coastal rates being the highest, suggesting that natural environmental variability is an important factor. Photoproduction rates at 297 nm were found to be constant at individual locations with increasing irradiation time. Relative photoproduction rates from this work are compared to previously measured rates from coastal sea water.

  18. Role of photoproducts in the cytotoxic action of selenomerocyanine-mediated photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Sieber, Fritz; Daziano, Jean-Pierre; Sampson, Reynee W.; Tsujino, Ichiro; Miyagi, Kiyoko; Ostrowski, Martin D.; Anderson, Gregory S.; Guenther, Wolfgang H.; Krieg, Marianne

    2005-04-01

    Many Type II photosensitizers are substrates of the singlet oxygen they generate. They are, therefore, converted to photoproducts when exposed to light in the presence of oxygen. While most photoproducts appear to be biologically inert, one of the photoproducts generated by selenomerocyanine photosensitizers is a form of elemental selenium that is surprisingly toxic to tumor cells if allowed to form conjugates with serum albumin or lipoproteins. Albumin and lipoproteins act as delivery vehicles for the cytotoxic entity, exploiting the fact that many tumor cells have an increased capacity to bind and internalize albumin and/or lipoproteins. The cytotoxic mechanism of Se(0)-protein conjugates is not yet fully understood but is obviously quite different from the singlet oxygen-mediated mechanism of merocyanine-mediated photodynamic therapy (PDT). Whereas merocyanine-PDT is directed against the plasma membrane, is more effective at 4 °C than at room temperature, and is inhibited by excess albumin and lipoproteins, selenomerocyanine-derived cytotoxic photoproducts act on intracellular targets, are ineffective at low temperatures, and require albumin or lipoproteins as carrier molecules. The discovery of cytotoxic Se(0)-protein conjugates provides a rare example of photoproducts contributing substantially to the cytotoxic effect of PDT and challenges the widely held notion that elemental selenium is biologically inert.

  19. Probing the strange nature of the nucleon with phi photoproduction

    SciTech Connect

    Lowry, M.M.

    1997-03-06

    The presence inside the nucleon of a significant component of strange-antistrange quark pairs has been invoked to explain a number of current puzzles in the low energy realm of QCD. The {sigma} term in {pi}N scattering is a venerable conundrum which can be explained with a 10%--20% admixture. The spin crisis brought on by the EMC result and follow on experiments was first interpreted as requiring a large strange content of s quarks whose spin helped cancel the contribution of the u and d quarks to the nucleon spin, again of order 10%. Excess phi meson production in p{anti p} annihilation at LEAR has also been explained in terms of up to a 19% admixture of s{anti s} pairs. Charm production in deep-inelastic neutrino scattering would appear to provide evidence for a 3% strange sea. It is clear that a definite probe of the strange quark content would be an invaluable tool in unraveling a number of mysteries. The longitudinal beam target asymmetry in {psi} photoproduction is a particularly sensitive probe of that content. It is explored here.

  20. Hydrogen photoproduction by use of photosynthetic organisms and biomimetic systems.

    PubMed

    Allakhverdiev, Suleyman I; Kreslavski, Vladimir D; Thavasi, Velmurugan; Zharmukhamedov, Sergei K; Klimov, Vyacheslav V; Nagata, Toshi; Nishihara, Hiroshi; Ramakrishna, Seeram

    2009-02-01

    Hydrogen can be important clean fuel for future. Among different technologies for hydrogen production, oxygenic natural and artificial photosyntheses using direct photochemistry in synthetic complexes have a great potential to produce hydrogen, since both use clean and cheap sources: water and solar energy. Artificial photosynthesis is one way to produce hydrogen from water using sunlight by employing biomimetic complexes. However, splitting of water into protons and oxygen is energetically demanding and chemically difficult. In oxygenic photosynthetic microorganisms such as algae and cyanobacteria, water is split into electrons and protons, which during primary photosynthetic process are redirected by photosynthetic electron transport chain, and ferredoxin, to the hydrogen-producing enzymes hydrogenase or nitrogenase. By these enzymes, e- and H+ recombine and form gaseous hydrogen. Biohydrogen activity of hydrogenase can be very high but it is extremely sensitive to photosynthetic O2. In contrast, nitrogenase is insensitive to O2, but has lower activity. At the moment, the efficiency of biohydrogen production is low. However, theoretical expectations suggest that the rates of photon conversion efficiency for H2 bioproduction can be high enough (>10%). Our review examines the main pathways of H2 photoproduction by using of photosynthetic organisms and biomimetic photosynthetic systems.

  1. The Determination of Pseudoscalar Meson Photoproduction Amplitudes from Complete Experiments

    SciTech Connect

    A. M. Sandorfi, S. Hoblit, H. Kamano, and T-S. H. Lee

    2011-10-01

    A new generation of complete experiments is currently underway with the goal of performing a high precision extraction of pseudoscalar meson photo-production amplitudes. Here we review the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single, double and triple-polarization terms involving 16 spin-dependent observables. Analytic expressions that determine the recoil baryon polarization are also presented. Different conventions are in use in the literature and we have used a numerical calculation of cross sections from Chew-Goldberger-Low-Nambu amplitudes with arbitrary spin projections to clarify apparent sign differences. As an illustration of the use of this machinery, we carry out a multipole analysis of the gammap --> K+Lambda reaction and examine the impact of recently published polarization measurements. In fitting multipoles, we use a combined Monte Carlo sampling of the amplitude space, with gradient minimization, and find a shallow chi2 valley pitted with a very large number of local minima, despite the inclusion of recent data on 8 different observables. We conclude that, while a mathematical solution to the problem of determining an amplitude free of ambiguities may require 8 observables, as has been pointed out in the literature, experiments with realistically achievable uncertainties will require a significantly larger number.

  2. Model Selection in the Analysis of Photoproduction Data

    NASA Astrophysics Data System (ADS)

    Landay, Justin

    2017-01-01

    Scattering experiments provide one of the most powerful and useful tools for probing matter to better understand its fundamental properties governed by the strong interaction. As the spectroscopy of the excited states of nucleons enters a new era of precision ushered in by improved experiments at Jefferson Lab and other facilities around the world, traditional partial-wave analysis methods must be adjusted accordingly. In this poster, we present a rigorous set of statistical tools and techniques that we implemented; most notably, the LASSO method, which serves for the selection of the simplest model, allowing us to avoid over fitting. In the case of establishing the spectrum of exited baryons, it avoids overpopulation of the spectrum and thus the occurrence of false-positives. This is a prerequisite to reliably compare theories like lattice QCD or quark models to experiments. Here, we demonstrate the principle by simultaneously fitting three observables in neutral pion photo-production, such as the differential cross section, beam asymmetry and target polarization across thousands of data points. Other authors include Michael Doring, Bin Hu, and Raquel Molina.

  3. Diffractive Higgs boson photoproduction in ultraperipheral collisions at LHC

    SciTech Connect

    Gay Ducati, M. B.; Silveira, G. G.

    2010-10-01

    A new production mechanism for the standard model Higgs boson in ultraperipheral collisions at the LHC, which allows central exclusive diffractive production by double pomeron exchange in photon-proton processes, is presented. The Higgs boson is centrally produced by gluon fusion with two large rapidity gaps emerging in the final state, being the main experimental signature for this process. As already studied for Pomeron-Pomeron and two-photon processes, the Higgs boson photoproduction is studied within this new mechanism in proton-proton (pp) and proton-nucleus (pA) collisions, where each system has a different dynamics to be taken into account. As a result, this mechanism predicts a production cross section for pp collisions of about 1.8 fb, which is similar to that obtained in Pomeron-Pomeron processes. Besides, in pPb collisions the cross sections have increased to about 0.6 pb, being comparable with the results of two-photon processes in pAu collisions. Therefore, as the rapidity gap survival probability is an open question in high-energy physics, an analysis for different values of this probability shows how competitive the mechanisms are in the LHC kinematical regime.

  4. Photoproduction of ω mesons off protons and neutrons

    NASA Astrophysics Data System (ADS)

    Dietz, F.; Metag, V.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Belogazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, C.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Höffgren, S.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Nikonov, V. A.; Nanova, M.; Novinski, D. V.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Rostomyan, T.; Roy, A.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Shklyar, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walter, D.; Wendel, C.; Wilson, A.

    2015-01-01

    ω photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The ω meson has been identified via the ω → π0 γ → γγγ decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for ω mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of ≈ 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV < E γ < 1.6 GeV. For higher incident beam energies this factor goes down to ≈ 1.1 at 2.0 GeV. The cross-sections of this work have been used as normalization for transparency ratio measurements.

  5. Neutron Skin of Pb208 from Coherent Pion Photoproduction

    NASA Astrophysics Data System (ADS)

    Tarbert, C. M.; Watts, D. P.; Glazier, D. I.; Aguar, P.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Bekrenev, V.; Boillat, B.; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R.; Downie, E. J.; Foehl, K.; Grabmayr, P.; Gregor, R.; Heid, E.; Hornidge, D.; Jahn, O.; Kashevarov, V. L.; Knezevic, A.; Kondratiev, R.; Korolija, M.; Kotulla, M.; Krambrich, D.; Krusche, B.; Lang, M.; Lisin, V.; Livingston, K.; Lugert, S.; MacGregor, I. J. D.; Manley, D. M.; Martinez, M.; McGeorge, J. C.; Mekterovic, D.; Metag, V.; Nefkens, B. M. K.; Nikolaev, A.; Novotny, R.; Owens, R. O.; Pedroni, P.; Polonski, A.; Prakhov, S. N.; Price, J. W.; Rosner, G.; Rost, M.; Rostomyan, T.; Schadmand, S.; Schumann, S.; Sober, D.; Starostin, A.; Supek, I.; Thomas, A.; Unverzagt, M.; Walcher, Th.; Zana, L.; Zehr, F.; Crystal Ball at MAMI; A2 Collaboration

    2014-06-01

    Information on the size and shape of the neutron skin on Pb208 is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be cn=6.70±0.03(stat.) fm and an=0.55±0.01(stat.)-0.03+0.02(sys.) fm, respectively, corresponding to a neutron skin thickness Δrnp=0.15±0.03(stat.)-0.03+0.01(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of Pb208 has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.

  6. Photoproduction of $\\pi^+ \\pi^-$ meson pairs on the proton

    SciTech Connect

    Marco A. Battaglieri; DeVita, Raffaella; Szczepaniak, Adam P.

    2009-10-01

    The exclusive reaction $\\gamma p \\to p \\pi^+ \\pi^-$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4<-t<1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was about 20 pb$^{-1}$. The reaction was isolated by detecting the $\\pi^+$ and proton in CLAS, and reconstructing the $\\pi^-$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves in the $M_{\\pi^+\\pi^-}$ mass range $0.4-1.4$ GeV were derived performing a partial wave expansion of the extracted moments. Besides the dominant contribution of the $\\rho(770)$ meson in the $P$-wave, evidence for the $f_0(980)$ and the $f_2(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\\sigma/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the $f_0(980)$ has been measured in a photoproduction experiment.

  7. Rescattering in Meson Photoproduction off Few Body Systems

    SciTech Connect

    Jean-Marc Laget

    2006-04-01

    Exclusive reactions induced at high momentum transfer in few body systems allow to adjust the formation time of the produced particles to the distance between two nucleons in the target. They are the best windows to study the propagation of exotic configurations of hadrons such as for instance the onset of color transparency. It may appear earlier in meson photo-production reactions, in the strange sector more particularly, than in more classical quasi elastic scattering of electrons. More generally, those reactions provide them with the best tool to determine the cross section of the scattering of various hadrons (strange particles, vector mesons) with nucleon, to better understand the mechanisms of their formation in cold hadronic matter, and to access the production of possible exotic states. At the top of the unitary rescattering peak (triangular logarithmic singularity), the reaction amplitude is on solid ground since it depends only on on-shell elementary amplitudes and on low momentum components of the nuclear wave function.

  8. ϕ-meson photoproduction on hydrogen in the neutral decay mode

    NASA Astrophysics Data System (ADS)

    Seraydaryan, H.; Amaryan, M. J.; Gavalian, G.; Baghdasaryan, H.; Weinstein, L.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

    2014-05-01

    We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp →pϕ(KSKL). The experiment was performed with a tagged photon beam of energy 1.6≤Eγ≤3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp →pKSX to be KL. The presented results significantly enlarge the existing data on ϕ photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of ϕ photoproduction.

  9. phi-meson photoproduction on Hydrogen in the neutral decay mode

    SciTech Connect

    Seraydaryan, Helena; Amaryan, Moscov J.; Gavalian, Gagik; Baghdasaryan, Hovhannes A.; Weinstein, Larry

    2014-05-01

    We report the first measurement of the photoproduction cross section of the $\\phi$ meson in its neutral decay mode in the reaction $\\gamma p \\to p\\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \\le E_\\gamma \\le 3.6$ GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The $p \\phi$ final state is identified via reconstruction of $K_S$ in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction $\\gamma p \\to p K_S X$ to be $K_L$. The presented results significantly enlarge the existing data on $\\phi$-photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of $\\phi$ photoproduction.

  10. Double and single pion photoproduction within a dynamical coupled-channels model

    SciTech Connect

    Hiroyuki Kamano; Julia-Diaz, Bruno; Lee, T. -S. H.; Matsuyama, Akihiko; Sato, Toru

    2009-12-16

    Within a dynamical coupled-channels model which has already been fixed from analyzing the data of the πN → πN and γN → πN reactions, we present the predicted double pion photoproduction cross sections up to the second resonance region, W < 1.7 GeV. The roles played by the different mechanisms within our model in determining both the single and double pion photoproduction reactions are analyzed, focusing on the effects due to the direct γN → ππN mechanism, the interplay between the resonant and non-resonant amplitudes, and the coupled-channels effects. As a result, the model parameters which can be determined most effectively in the combined studies of both the single and double pion photoproduction data are identified for future studies.

  11. Double and single pion photoproduction within a dynamical coupled-channels model

    DOE PAGES

    Hiroyuki Kamano; Julia-Diaz, Bruno; Lee, T. -S. H.; ...

    2009-12-16

    Within a dynamical coupled-channels model which has already been fixed from analyzing the data of the πN → πN and γN → πN reactions, we present the predicted double pion photoproduction cross sections up to the second resonance region, W < 1.7 GeV. The roles played by the different mechanisms within our model in determining both the single and double pion photoproduction reactions are analyzed, focusing on the effects due to the direct γN → ππN mechanism, the interplay between the resonant and non-resonant amplitudes, and the coupled-channels effects. As a result, the model parameters which can be determined mostmore » effectively in the combined studies of both the single and double pion photoproduction data are identified for future studies.« less

  12. Voriconazole N-oxide and its UVB photoproduct sensitize keratinocytes to UVA

    PubMed Central

    Ona-Vu, K.; Oh, D.H.

    2015-01-01

    Background The antifungal agent, voriconazole, is associated with phototoxicity and photocarcinogenicity. Prior work has indicated that voriconazole and its hepatic N-oxide metabolite do not sensitize keratinocytes to ultraviolet B (UVB). Clinical observations have suggested ultraviolet A (UVA) may be involved. Objectives To determine the photochemistry and photobiology of voriconazole and its major hepatic metabolite, voriconazole N-oxide. Methods Voriconazole and voriconazole N-oxide were spectrophotometrically monitored following various doses of UVB. Cultured human keratinocytes were treated with parental drugs or with their UVB photoproducts, and survival following UVA irradiation was measured by thiazolyl blue metabolism. Reactive oxygen species and 8-oxoguanine were monitored by fluorescence microscopy. Results Voriconazole and voriconazole N-oxide have varying ultraviolet B (UVB) absorption but do not acutely sensitize cultured human keratinocytes following UVB exposure. However, sustained UVB exposures produced notable dose- and solvent-dependent changes in the absorption spectra of voriconazole N-oxide which in aqueous solution acquires a prominent ultraviolet A (UVA) absorption band, suggesting formation of a discrete photoproduct. Neither the parental drugs nor their photoproducts sensitized cells to UVB though all but voriconazole N-oxide were moderately toxic to cells in the dark. Notably, both voriconazole N-oxide and its UVB photoproduct, but not voriconazole or its photoproduct, additionally sensitized cells to UVA by >3-fold relative to controls in association with UVA-induced reactive oxygen species and 8-oxoguanine levels. Conclusions Voriconazole N-oxide and its UVB-photoproduct act as UVA-sensitizers that generate reactive oxygen species and that produce oxidative DNA damage. These results suggest a mechanism for the phototoxicity and photocarcinogenicity observed with voriconazole treatment. PMID:25919127

  13. Low-energy theorems for pion photoproduction from nuclei and pion-nucleus coupling constants

    SciTech Connect

    Radutskii, G.M.; Serdyutskii, V.A.

    1982-10-01

    New low-energy theorems for pion photoproduction in light nuclei are derived using a model that allows one to extract all the information contained in the current algebra and the CVC and PCAC hypotheses. From the comparison with the experimental total cross sections for threshold photoproduction of charged pions on the nuclei /sup 6/Li, /sup 12/C, and /sup 14/N, the values of the pion-nucleus coupling constants are obtained and the magnitude of the electric quadrupole moment of the /sup 12/N nucleus is predicted.

  14. Preliminary results for the helicity asymmetry E for eta photoproduction on the proton

    SciTech Connect

    B. T. Morrison, M. Dugger, B. G. Ritchie, CLAS Collaboration

    2012-04-01

    Polarization observables are an important tool for clarifying the nucleon resonance spectrum. No previous measurements for double polarization asymmetries have been published for eta photoproduction. Double polarization measurements have been made at Jefferson Lab using a polarized photon beam and protons in a polarized frozen spin target (FROST). Data were taken during the first running period of FROST using the CLAS detector with photon energies from 0.33 to 2.35 GeV. Preliminary results for the E polarization observable for eta meson photoproduction from the proton at threshold and above, along with comparisons to several theoretical predictions are presented.

  15. Determination of E and G Observables in n Photoproduction on the CLAS Frozen Spin Target (FROST)

    SciTech Connect

    Senderovich, Igor; Morrison, Brian T.; Dugger, Michael R.; Ritchie, Barry G.; Tucker, Ross J.

    2014-01-01

    Polarization observables are vital for disentangling overlapping resonances in the baryon spectrum. Extensive data have been collected at Jefferson Lab in Hall B with circularly and linearly polarized tagged photon beam incident on longitudinally polarized protons provided by the Frozen Spin Target (FROST). The focus of the described work is on η photoproduction, which acts as an "isospin filter", isolating the N*(I = 1/2) resonances. Preliminary results for the double-polarization observables E and G are presented. There are currently no data on these in the world database for η photoproduction.

  16. CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab

    SciTech Connect

    Eugene Pasyuk

    2009-12-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams provide unique conditions for this type of experiments. Recent addition of the Frozen Spin Target (FROST) gives a remarkable opportunity to measure double and triple polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete experiment becomes possible and will allow model independent extraction of the reaction amplitude. An overview of the experiment and its current status is presented.

  17. Genome sequence of Corynebacterium nuruki S6-4 T, isolated from alcohol fermentation starter.

    PubMed

    Shin, Na-Ri; Whon, Tae Woong; Roh, Seong Woon; Kim, Min-Soo; Jung, Mi-Ja; Lee, Jina; Bae, Jin-Woo

    2011-08-01

    Corynebacterium nuruki S6-4(T), isolated from Korean alcohol fermentation starter, is a strictly aerobic, nonmotile, Gram-positive, and rod-shaped bacterium belonging to the genus Corynebacterium and the actinomycete group. We report here the draft genome sequence of C. nuruki strain S6-4(T) (3,106,595 bp, with a G+C content of 69.5%).

  18. Genome Sequence of Corynebacterium nuruki S6-4T, Isolated from Alcohol Fermentation Starter▿

    PubMed Central

    Shin, Na-Ri; Whon, Tae Woong; Roh, Seong Woon; Kim, Min-Soo; Jung, Mi-Ja; Lee, Jina; Bae, Jin-Woo

    2011-01-01

    Corynebacterium nuruki S6-4T, isolated from Korean alcohol fermentation starter, is a strictly aerobic, nonmotile, Gram-positive, and rod-shaped bacterium belonging to the genus Corynebacterium and the actinomycete group. We report here the draft genome sequence of C. nuruki strain S6-4T (3,106,595 bp, with a G+C content of 69.5%). PMID:21685278

  19. Study of the Two-pion Photoproduction on the Deuteron

    SciTech Connect

    Graham, Lewis P.

    2012-12-01

    Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the yN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Delta resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large

  20. Photoproduction of the f1(1285 ) meson

    NASA Astrophysics Data System (ADS)

    Dickson, R.; Schumacher, R. A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Holtrop, M.; Hicks, K.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Markov, N.; Mokeev, V.; Moriya, K.; Munevar, E.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Salgado, C.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, E. S.; Smith, G. D.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Stankovic, I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.; CLAS Collaboration

    2016-06-01

    The f1(1285 ) meson with mass 1281.0 ±0.8 MeV/c2 and width 18.4 ±1.4 MeV (full width at half maximum) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the η π+π-,K+K¯0π- , and K-K0π+ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the η π+π- final-state Dalitz distribution are consistent with the axial-vector JP=1+ f1(1285 ) identity, rather than the pseudoscalar 0- η (1295 ) . The production mechanism is more consistent with s -channel decay of a high-mass N* state and not with t -channel meson exchange. Decays to η π π go dominantly via the intermediate a0±(980 ) π∓ states, with the branching ratio Γ [a0π (noK ¯K )] /Γ [η π π (all)] =0.74 ±0.09 . The branching ratios Γ (K K ¯π ) /Γ (η π π ) =0.216 ±0.033 and Γ (γ ρ0) /Γ (η π π ) =0.047 ±0.018 were also obtained. The first is in agreement with previous data for the f1(1285 ) , while the latter is lower than the world average.

  1. Photoproduction of π0-pairs off protons and off neutrons

    NASA Astrophysics Data System (ADS)

    Dieterle, M.; Oberle, M.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Bantawa, K.; Bartolome, P. A.; Beck, R.; Bekrenev, V.; Berghäuser, H.; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Costanza, S.; Demissie, B.; Downie, E. J.; Drexler, P.; Fil'kov, L. V.; Fix, A.; Garni, S.; Glazier, D. I.; Hamilton, D.; Heid, E.; Hornidge, D.; Howdle, D.; Huber, G. M.; Jahn, O.; Jude, T. C.; Käser, A.; Kashevarov, V. L.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Krusche, B.; Lisin, V.; Livingston, K.; MacGregor, I. J. D.; Maghrbi, Y.; Mancell, J.; Manley, D. M.; Marinides, Z.; McGeorge, J. C.; McNicoll, E.; Mekterovic, D.; Metag, V.; Micanovic, S.; Middleton, D. G.; Mushkarenkov, A.; Nikolaev, A.; Novotny, R.; Ostrick, M.; Otte, P.; Oussena, B.; Pedroni, P.; Pheron, F.; Polonski, A.; Prakhov, S.; Robinson, J.; Rostomyan, T.; Schumann, S.; Sikora, M. H.; Sober, D. I.; Starostin, A.; Strub, Th.; Supek, I.; Thiel, M.; Thomas, A.; Unverzagt, M.; Walford, N. K.; Watts, D. P.; Werthmüller, D.; Witthauer, L.

    2015-11-01

    Total cross sections, angular distributions, and invariant-mass distributions have been measured for the photoproduction of π0π0 pairs off free protons and off nucleons bound in the deuteron. The experiments were performed at the MAMI accelerator facility in Mainz using the Glasgow photon tagging spectrometer and the Crystal Ball/TAPS detector. The accelerator delivered electron beams of 1508 and 1557MeV, which produced bremsstrahlung in thin radiator foils. The tagged photon beam covered energies up to 1400MeV. The data from the free proton target are in good agreement with previous measurements and were only used to test the analysis procedures. The results for differential cross sections (angular distributions and invariant-mass distributions) for free and quasi-free protons are almost identical in shape, but differ in absolute magnitude up to 15%. Thus, moderate final-state interaction effects are present. The data for quasi-free neutrons are similar to the proton data in the second resonance region (final-state invariant masses up to ≈ 1550 MeV), where both reactions are dominated by the N(1520)3/2- → Δ(1232)3/2+π decay. At higher energies, angular and invariant-mass distributions are different. A simple analysis of the shapes of the invariant-mass distributions in the third resonance region is consistent with strong contributions of an N^{star}→ Nσ decay for the proton, while the reaction is dominated by a sequential decay via a Δπ intermediate state for the neutron. The data are compared to predictions from the Two-Pion-MAID model and the Bonn-Gatchina coupled-channel analysis.

  2. Rho0 Photoproduction in Ultra-Peripheral Relativistic Heavy Ion Collisions with STAR

    SciTech Connect

    STAR Coll

    2007-12-20

    Photoproduction reactions occur when the electromagnetic field of a relativistic heavy ion interacts with another heavy ion. The STAR collaboration presents a measurement of {rho}{sup 0} and direct {pi}{sup +}{pi}{sup -} photoproduction in ultra-peripheral relativistic heavy ion collisions at {radical}s{sub NN} = 200 GeV. We observe both exclusive photoproduction and photoproduction accompanied by mutual Coulomb excitation. We find a coherent cross-section of {sigma}(AuAu {yields} Au*Au* {rho}{sup 0}) = 530 {+-} 19 (stat.) {+-} 57 (syst.) mb, in accord with theoretical calculations based on a Glauber approach, but considerably below the predictions of a color dipole model. The {rho}{sup 0} transverse momentum spectrum (p{sub T}{sup 2}) is fit by a double exponential curve including both coherent and incoherent coupling to the target nucleus; we find {sigma}{sub inc}/{sigma}{sub coh} = 0.29 {+-} 0.03 (stat.) {+-} 0.08 (syst.). The ratio of direct {pi}{sup +}{pi}{sup -} production is comparable to that observed in {gamma}p collisions at HERA, and appears to be independent of photon energy. Finally, the measured {rho}{sup 0} spin helicity matrix elements agree within errors with the expected s-channel helicity conservation.

  3. Beam asymmetry {Sigma} measurements of {pi}{sup -} photoproduction on neutrons

    SciTech Connect

    Mandaglio, G.; Manganaro, M.; Giardina, G.; Mammoliti, F.; Bellini, V.; Giusa, A.; Randieri, C.; Russo, G.; Sperduto, M. L.; Bocquet, J. P.; Lleres, A.; Rebreyend, D.; D'Angelo, A.; Fantini, A.; Franco, D.; Schaerf, C.; Vegna, V.

    2010-10-15

    The -beam asymmetry {Sigma} in the photoproduction of negative pions on quasi-free neutrons in a deuterium target was measured at the Grenoble Anneau Accelerateur Laser in the energy interval 700-1500 MeV and over a wide angular range, using polarized and tagged photons. Results are compared with recent partial-wave analyses.

  4. Beam asymmetry Σ for π0 and η photoproduction on the proton at GlueX

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu; GlueX Collaboration

    2016-09-01

    Measurements of meson photoproduction at high energies began almost 50 years ago with bubble chamber experiments at SLAC, DESY, and Cambridge. These data have been successfully described through Regge theory in terms of t-channel quasi-particle exchange. High statistics measurements of pseudoscalar meson photoproduction at GlueX, using the 9 GeV linearly-polarized, tagged photon beam in Jefferson Lab's Hall D, will provide important new constraints on these Regge models. These measurements will test our understanding of the photoproduction mechanism at high energy, which is a necessary first step toward the broader meson spectroscopy program at GlueX. Through finite energy sum rules, these measurements can also impose new constraints on the extraction of nucleon resonances from low energy photoproduction data. In this talk, preliminary results for the linearly polarized photon beam asymmetry Σ for the exclusive reactions γp -> pπ0 and γp -> pη will be presented. These are the first measurements of the η beam asymmetry at these energies. Supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and the China Scholarship Council No. 201506275156.

  5. Helicity Asymmetry Measurement for pi0 Photoproduction with FROST

    SciTech Connect

    Iwamoto, Hideko

    2011-08-15

    This thesis reports on the first helicity asymmetry measurement for single neutral pion photoproduction using the CLAS detector in Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This measurement used longitudinally polarized protons and circularly polarized photons at energies between 350 MeV and 2400 MeV. The experimental results are compared to three available model calculations.

  6. Photoproduction of an isovector. rho. pi. state at 1775 MeV

    SciTech Connect

    Condo, G.T.; Handler, T.; Shimony, J.; Abe, K.; Armenteros, R.; Austern, M.; Bacon, T.C.; Ballam, J.; Bingham, H.H.; Brau, J.E.; Braune, K.; Brick, D.; Bugg, W.M.; Butler, J.M.; Cameron, W.; Cohn, H.O.; Colley, D.C.; Dado, S.; Diamond, R.; Dingus, P.; Erickson, R.; Falicov, A.; Field, R.C.; Fortney, L.R.; Franek, B.; Fujiwara, N.; Glanzman, T.; Godfrey, I.M.; Goldberg, J.J.; Goshaw, A.T.; Hall, G.; Hancock, E.R.; Hargis, H.J.; Hart, E.L.; Harwin, M.J.; Hasegawa, K.; Hulsizer, R.I.; Jobes, M.; Kafka, T.; Kalmus, G.E.; Kelsey, D.P.; Kent, J.; Kitagaki, T.; Levy, A.; Lucas, P.W.; Mann, W.A.; McCrory, E.S.; Merenyi, R.; Milburn, R.; Milstene, C.; Moffeit, K.C.; Napier, A.; Noguchi, S.; O'Dell, V.R.; O'Neale, S.; Palounek, A.P.T.; Pless, I.A.; Rankin, P.; Robertson, W.J.; Sagawa, H.; Sato, T.; Schneps, J.; Sewell, S.J.; Shank, J.; Shapiro, A.M.; Sugahara, R.; Takahashi, K.; Tamai, K.; Tanaka, S.; Tether, S.; Waide, D.A.; Walker, W.D.; White, S.L.; Widgoff, M.; Wilkins, C.G.; Wolbers, S.; Wo

    1991-05-01

    Evidence is presented for the charge-exchange photoproduction, in two distinct reactions, of an isovector {rho}{pi} state of mass {similar to}1775 MeV. Results of an analysis of the decay-angular distributions are also presented, from which it is concluded that {ital J}{sup {ital P}}=1{sup {minus}}, 2{sup {minus}}, or 3{sup +}.

  7. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    DOE PAGES

    Ronchen, D.; Doring, M.; Haberzettl, H.; ...

    2015-06-25

    Themore » $$\\eta N$$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $$\\Delta$$ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of $$E\\sim 2.3$$ GeV is analyzed, including data on differential cross sections, and single and double polarization observables. resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $$\\pi N\\to \\pi N$$, $$\\eta N$$, $$K\\Lambda$$ and $$K\\Sigma$$. For the analysis, the so-called J\\"ulich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. Furthermore, the influence of recent MAMI $T$ and $F$ asymmetry data on the eta photoproduction amplitude is discussed in detail.« less

  8. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    SciTech Connect

    Ronchen, D.; Doring, M.; Haberzettl, H.; Haidenbauer, J.; MeiBner, U. -G.; Nakayama, K.

    2015-06-25

    The $\\eta N$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $\\Delta$ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of $E\\sim 2.3$ GeV is analyzed, including data on differential cross sections, and single and double polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $\\pi N\\to \\pi N$, $\\eta N$, $K\\Lambda$ and $K\\Sigma$. For the analysis, the so-called J\\"ulich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. Furthermore, the influence of recent MAMI $T$ and $F$ asymmetry data on the eta photoproduction amplitude is discussed in detail.

  9. Survey of selected seaweeds for simultaneous photoproduction of hydrogen and oxygen

    SciTech Connect

    Greenbaum, E.; Ramus, J.

    1983-03-01

    Then seaweed species were surveyed for simultaneous photoevolution of hydrogen and oxygen. In an attempt to induce hydrogenase activity (as measured by hydrogen photoproduction) the seaweeds were maintained under anaerobiosis in CO/sub 2/-free seawater for varying lengths of time. Although oxygen evolution was observed in every alga studied, hydrogen evolution was not observed. One conclusion of this research is that, in contrast to the microscopic algae, there is not a single example of a macroscopic alga for which the photoevolution of hydrogen has been observed, in spite of the fact that there are now at least nine macroscopic algal species known for which hydrogenase activity has been reported (either by dark hydrogen evolution or light-activated hydrogen uptake). These results are in conflict with the conventional view that algal hydrogenase can catalyze a multiplicity of reactions, one of which is the photoproduction of molecular hydrogen. Two possible explanations for the lack of hydrogen photoproduction in macroscopic algae are presented. It is postulated that electron acceptors other than carbon dioxide can take up reducing equivalents from Photosystem I to the measurable exclusion of hydrogen photoproduction. Alternatively, the hydrogenase system in macroscopic algae may be primarily a hydrogen-uptake system with respect to light-activated reactions. A simple kinetic argument based on recent measurements of the photosynthetic turnover times of simultaneous light-activated hydrogen and oxygen production is presented that supports the second explanation. 25 references, 3 figures, 1 table.

  10. Backward-angle {eta} photoproduction from protons at E{sub {gamma}}=1.6-2.4 GeV

    SciTech Connect

    Sumihama, M.; Ejiri, H.; Fujiwara, M.; Hotta, T.; Kato, Y.; Kohri, H.; Miyabe, M.; Muramatsu, N.; Nakano, T.; Shimizu, A.; Yorita, T.; Yosoi, M.; Ahn, D. S.; Ahn, J. K.; Akimune, H.; Asano, Y.; Date, S.; Ohashi, Y.; Ohkuma, H.; Toyokawa, H.

    2009-11-15

    Differential cross sections for {eta} photoproduction from protons have been measured at E{sub {gamma}}=1.6-2.4 GeV in the backward direction. A bump structure has been observed above 2.0 GeV in the total energy. No such bump is observed in {eta}{sup '},{omega}, and {pi}{sup 0} photoproductions. It is inferred that this unique structure in {eta} photoproduction is due to a baryon resonance with a large ss component that is strongly coupled to the {eta}N channel.

  11. Independent movement of the voltage sensors in KV2.1/KV6.4 heterotetramers

    PubMed Central

    Bocksteins, Elke; Snyders, Dirk J.; Holmgren, Miguel

    2017-01-01

    Heterotetramer voltage-gated K+ (KV) channels KV2.1/KV6.4 display a gating charge-voltage (QV) distribution composed by two separate components. We use state dependent chemical accessibility to cysteines substituted in either KV2.1 or KV6.4 to assess the voltage sensor movements of each subunit. By comparing the voltage dependences of chemical modification and gating charge displacement, here we show that each gating charge component corresponds to a specific subunit forming the heterotetramer. The voltage sensors from KV6.4 subunits move at more negative potentials than the voltage sensors belonging to KV2.1 subunits. These results indicate that the voltage sensors from the tetrameric channels move independently. In addition, our data shows that 75% of the total charge is attributed to KV2.1, while 25% to KV6.4. Thus, the most parsimonious model for KV2.1/KV6.4 channels’ stoichiometry is 3:1. PMID:28139741

  12. 43 CFR 4130.6-4 - Special grazing permits or leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Special grazing permits or leases. 4130.6... LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-4 Special grazing permits or leases. Special grazing permits...

  13. The Trichoderma reesei Cry1 Protein Is a Member of the Cryptochrome/Photolyase Family with 6–4 Photoproduct Repair Activity

    PubMed Central

    Guzmán-Moreno, Jesús; Flores-Martínez, Alberto; Brieba, Luis G.; Herrera-Estrella, Alfredo

    2014-01-01

    DNA-photolyases use UV-visible light to repair DNA damage caused by UV radiation. The two major types of DNA damage are cyclobutane pyrimidine dimers (CPD) and 6–4 photoproducts (6-4PP), which are repaired under illumination by CPD and 6–4 photolyases, respectively. Cryptochromes are proteins related to DNA photolyases with strongly reduced or lost DNA repair activity, and have been shown to function as blue-light photoreceptors and to play important roles in circadian rhythms in plants and animals. Both photolyases and cryptochromes belong to the cryptochrome/photolyase family, and are widely distributed in all organisms. Here we describe the characterization of cry1, a member of the cryptochrome/photolyase protein family of the filamentous fungus Trichoderma reesei. We determined that cry1 transcript accumulates when the fungus is exposed to light, and that such accumulation depends on the photoreceptor Blr1 and is modulated by Envoy. Conidia of cry1 mutants show decreased photorepair capacity of DNA damage caused by UV light. In contrast, strains over-expressing Cry1 show increased repair, as compared to the parental strain even in the dark. These observations suggest that Cry1 may be stimulating other systems involved in DNA repair, such as the nucleotide excision repair system. We show that Cry1, heterologously expressed and purified from E. coli, is capable of binding to undamaged and 6-4PP damaged DNA. Photorepair assays in vitro clearly show that Cry1 repairs 6-4PP, but not CPD and Dewar DNA lesions. PMID:24964051

  14. Transcriptional and Posttranslational Regulation of Nucleotide Excision Repair: The Guardian of the Genome against Ultraviolet Radiation

    PubMed Central

    Park, Jeong-Min; Kang, Tae-Hong

    2016-01-01

    Ultraviolet (UV) radiation from sunlight represents a constant threat to genome stability by generating modified DNA bases such as cyclobutane pyrimidine dimers (CPD) and pyrimidine-pyrimidone (6-4) photoproducts (6-4PP). If unrepaired, these lesions can have deleterious effects, including skin cancer. Mammalian cells are able to neutralize UV-induced photolesions through nucleotide excision repair (NER). The NER pathway has multiple components including seven xeroderma pigmentosum (XP) proteins (XPA to XPG) and numerous auxiliary factors, including ataxia telangiectasia and Rad3-related (ATR) protein kinase and RCC1 like domain (RLD) and homologous to the E6-AP carboxyl terminus (HECT) domain containing E3 ubiquitin protein ligase 2 (HERC2). In this review we highlight recent data on the transcriptional and posttranslational regulation of NER activity. PMID:27827925

  15. Dynamically Complex [6+4] and [4+2] Cycloadditions in the Biosynthesis of Spinosyn A

    PubMed Central

    Patel, Ashay; Chen, Zhuo; Yang, Zhongyue; Gutiérrez, Osvaldo; Liu, Hung-wen; Houk, K. N.; Singleton, Daniel A.

    2017-01-01

    SpnF, an enzyme involved in the biosynthesis of spinosyn A, catalyzes a transannular Diels–Alder reaction. Quantum mechanical computations and dynamic simulations now show that this cycloaddition is not well described as either a concerted or stepwise process, and dynamical effects influence the identity and timing of bond formation. The transition state for the reaction is ambimodal and leads directly to both the observed Diels–Alder and an unobserved [6+4] cycloadduct. The potential energy surface bifurcates and the cycloadditions occur by dynamically stepwise modes featuring an “entropic intermediate”. A rapid Cope rearrangement converts the [6+4] adduct into the observed [4+2] adduct. Control of nonstatistical dynamical effects may serve as another way by which enzymes control reactions. PMID:26909570

  16. A quantum chemical perspective on (6-4) photolesion repair by photolyases.

    PubMed

    Dreuw, Andreas; Faraji, Shirin

    2013-12-14

    (6-4)-Photolyases are fascinating enzymes which repair (6-4)-DNA photolesions utilizing light themselves. It is well known that upon initial photo-excitation of an antenna pigment an electron is transferred from an adjacent FADH(-) cofactor to the photolesion initiating repair, i.e. restoration of the original undamaged DNA bases. Concerning the molecular details of this amazing repair mechanism, the early steps of energy transfer and catalytic electron generation are well understood, the terminal repair mechanism, however, is still a matter of ongoing debate. In this perspective article, recent results of quantum chemical investigations are presented, and their meaning for the repair mechanism under natural conditions is outlined. Consequences of natural light conditions, temperature and thermal equilibration are highlighted when issues like the initial protonation state of the relevant histidines and the lesion, or the direction of electron transfer are discussed.

  17. Targeted Inactivation of DNA Photolyase Genes in Medaka Fish (Oryzias latipes).

    PubMed

    Ishikawa-Fujiwara, Tomoko; Shiraishi, Eri; Fujikawa, Yoshihiro; Mori, Toshio; Tsujimura, Tohru; Todo, Takeshi

    2017-01-01

    Proteins of the cryptochrome/photolyase family (CPF) exhibit sequence and structural conservation, but their functions are divergent. Photolyase is a DNA repair enzyme that catalyzes the light-dependent repair of ultraviolet (UV)-induced photoproducts, whereas cryptochrome acts as a photoreceptor or circadian clock protein. Two types of DNA photolyase exist: CPD photolyase, which repairs cyclobutane pyrimidine dimers (CPDs), and 6-4 photolyase, which repairs 6-4 pyrimidine-pyrimidone photoproducts (6-4PPs). Although the Cry-DASH protein is classified as a cryptochrome, it also has light-dependent DNA repair activity. To determine the significance of the three light-dependent repair enzymes in recovering from solar UV-induced DNA damage at the organismal level, we generated mutants in each gene in medaka using the CRISPR genome editing technique. The light-dependent repair activity of the mutants was examined in vitro in cultured cells and in vivo in skin tissue. Light-dependent repair of CPD was lost in the CPD photolyase-deficient mutant, whereas weak repair activity against 6-4PPs persisted in the 6-4 photolyase-deficient mutant. These results suggest the existence of a heretofore unknown 6-4PP repair pathway and thus improve our understanding of the mechanisms of defense against solar UV in vertebrates.

  18. Photolytic degradation of benorylate: effects of the photoproducts on cultured hepatocytes

    SciTech Connect

    Castell, J.V.; Gomez, M.J.; Mirabet, V.; Miranda, M.A.; Morera, I.M.

    1987-05-01

    The photodegradation of benorylate (4'-(acetamido)phenyl-2-acetoxybenzoate), a drug frequently used in rheumatoid arthritis therapy, has been examined under different sets of experimental conditions. Several photoproducts have been isolated and identified on the basis of their IR, NMR, and MS spectra. The most significant photochemical process is the photo-Fries rearrangement of benorylate, leading to 5-acetamido-2'-acetoxy-2-hydroxybenzophenone (1). This compound undergoes a rapid transacylation to the isomeric 5'-acetamido-2'-acetoxy-2-hydroxybenzophenone (2). A primary culture of rat hepatocytes has been used to evaluate the possible toxicity of these two benzophenones, keeping in mind the following criteria: leakage of cytosolic enzymes, attachment index to culture plates, gluconeogenesis from lactate and fructose, glycogen balance, and albumin synthesis. At the concentrations assayed, neither of the two major photoproducts of benorylate (benzophenones 1 and 2) had significant toxic effects on liver cells in culture.

  19. Extended study of prompt photon photoproduction at HERA with kT-factorization

    NASA Astrophysics Data System (ADS)

    Lipatov, A. V.; Malyshev, M. A.; Zotov, N. P.

    2013-10-01

    We reconsider prompt photon photoproduction at HERA in the framework of the kT-factorization QCD approach. The proposed method is based on the O(α2αs) amplitudes for γq→γgq and γg*→γqq¯ partonic subprocesses. Additionally, we take into account the O(α2αs2) box contributions γg→γg to the production cross sections. The unintegrated (or transverse momentum dependent) parton densities in the proton are determined using the Kimber-Martin-Ryskin prescription. Our consideration covers both inclusive and jet associated prompt photon photoproduction rates. We find that our numerical predictions agree well with the recent data taken by H1 and ZEUS Collaborations at HERA. We demonstrate that the box contributions are sizable and amount to up to ˜15% of the calculated total cross section.

  20. Double-polarization observable G in neutral-pion photoproduction off the proton

    NASA Astrophysics Data System (ADS)

    Thiel, A.; Eberhardt, H.; Lang, M.; Afzal, F.; Anisovich, A. V.; Bantes, B.; Bayadilov, D.; Beck, R.; Bichow, M.; Brinkmann, K.-T.; Böse, S.; Crede, V.; Dieterle, M.; Dutz, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Friedrich, St.; Frommberger, F.; Funke, Ch.; Goertz, St.; Gottschall, M.; Gridnev, A.; Grüner, M.; Gutz, E.; Hammann, D.; Hammann, Ch.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, Ph.; Honisch, Ch.; Jude, T.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Kammer, S.; Keshelashvili, I.; Klassen, P.; Kleber, V.; Klein, F.; Klempt, E.; Koop, K.; Krusche, B.; Kube, M.; Lopatin, I.; Mahlberg, Ph.; Makonyi, K.; Metag, V.; Meyer, W.; Müller, J.; Müllers, J.; Nanova, M.; Nikonov, V.; Piontek, D.; Reeve, S.; Reicherz, G.; Runkel, S.; Sarantsev, A.; Schmidt, Ch.; Schmieden, H.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thoma, U.; Urban, M.; van Pee, H.; Walther, D.; Wendel, Ch.; Wilson, A.; Winnebeck, A.; Witthauer, L.

    2017-01-01

    This paper reports on a measurement of the double-polarization observable G in π^0 photoproduction off the proton using the CBELSA/TAPS experiment at the ELSA accelerator in Bonn. The observable G is determined from reactions of linearly polarized photons with longitudinally polarized protons. The polarized photons are produced by bremsstrahlung off a diamond radiator of well-defined orientation. A frozen spin butanol target provides the polarized protons. The data cover the photon energy range from 617 to 1325 MeV and a wide angular range. The experimental results for G are compared to predictions by the Bonn-Gatchina (BnGa), Jülich-Bonn (JüBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed.

  1. Photolytic degradation of benorylate: effects of the photoproducts on cultured hepatocytes.

    PubMed

    Castell, J V; Gomez, M J; Mirabet, V; Miranda, M A; Morera, I M

    1987-05-01

    The photodegradation of benorylate [4'-(acetamido)phenyl-2-acetoxybenzoate], a drug frequently used in rheumatoid arthritis therapy, has been examined under different sets of experimental conditions. Several photoproducts have been isolated and identified on the basis of their IR, NMR, and MS spectra. The most significant photochemical process is the photo-Fries rearrangement of benorylate, leading to 5-acetamido-2'-acetoxy-2-hydroxybenzophenone (1). This compound undergoes a rapid transacylation to the isomeric 5'-acetamido-2'-acetoxy-2-hydroxybenzophenone (2). A primary culture of rat hepatocytes has been used to evaluate the possible toxicity of these two benzophenones, keeping in mind the following criteria: leakage of cytosolic enzymes, attachment index to culture plates, gluconeogenesis from lactate and fructose, glycogen balance, and albumin synthesis. At the concentrations assayed, neither of the two major photoproducts of benorylate (benzophenones 1 and 2) had significant toxic effects on liver cells in culture.

  2. Photoproduction of the rho^0 Meson on the Proton at Large Momentum Transfer

    SciTech Connect

    M. Battaglieri; E. Anciant; M. Anghinolfi; R. De Vita; E. Golovach; J. M. Laget; V. Mokeev; M. Ripani; G. Adams; M. J. Amaryan; D. S. Armstrong; B. Asavapibhop; G. Asryan; G. Audit; T. Auger; H. Avakian; S. Barrow; K. Beard; M. Bektasoglu; B. L. Berman; N. Bianchi; A. S. Biselli; S. Boiarinov; D. Branford; W. J. Briscoe; W. K. Brooks; V. D. Burkert; J. R. Calarco; G. P. Capitani; D. S. Carman; B. Carnahan; A. Cazes; C. Cetina; P. L. Cole; A. Coleman; D. Cords; P. Corvisiero; D. Crabb; H. Crannell; J. P. Cummings; E. DeSanctis; P. V. Degtyarenko; R. Demirchyan; H. Denizli; L. Dennis; K. V. Dharmawardane; K. S. Dhuga; C. Djalali; G. E. Dodge; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; M. Eckhause; H. Egiyan; K. S. Egiyan; L. Elouadrhiri; L. Farhi; R. J. Feuerbach; J. Ficenec; T. A. Forest; A. P. Freyberger; V. Frolov; H. Funsten; S. J. Gaff; M. Gai; S. Gilad; G. P. Gilfoyle; K. L. Giovanetti; K. Griffioen; M. Guidal; M. Guillo; V. Gyurjyan; D. Hancock; J. Hardie; D. Heddle; F. W. Hersman; K. Hicks; R. S. Hicks; M. Holtrop; C. E. Hyde-Wright; M. M. Ito; K. Joo; J. H. Kelley; M. Khandaker; W. Kim; A. Klein; F. J. Klein; M. Klusman; M. Kossov; L. H. Kramer; Y. Kuang; S. E. Kuhn; D. Lawrence; M. Lucas; K. Lukashin; R. W. Major; J. J. Manak; C. Marchand; S. McAleer; J. McCarthy; J. W. C. McNabb; B. A. Mecking; M. D. Mestayer; C. A. Meyer; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Muccifora; J. Mueller; G. S. Mutchler; J. Napolitano; S. O. Nelson; B. B. Niczyporuk; R. A. Niyazov; J. T. O'Brien; A. K. Opper; G. Peterson; S. A. Philips; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; B. M. Preedom; J. W. Price; D. Protopopescu; L. M. Qin; B. A. Raue; A. R. Reolon; G. Riccardi; G. Ricco; B. G. Ritchie; F. Ronchetti; P. Rossi; D. Rowntree; P. D. Rubin; K. Sabourov; C. Salgado; M. Sanzone-Arenhovel; V. Sapunenko; R. A. Schumacher; V. S. Serov; A. Shafi; Y. G. Sharabian; J. Shaw; A. V. Skabelin; E. S. Smith; T. Smith; L. C. Smith; D. I. Sober; M. Spraker; A. Stavinsky; S. Stepanyan; P. Stoler; M. Taiuti; S. Taylor; D. J. Tedeschi; L. Todor; R. Thompson; M. F. Vineyard; A. V. Vlassov; L. B. Weinstein; A. Weisberg; H. Weller; D. P. Weygand; C. S. Whisnant; E. Wolin; M. Wood; A. Yegneswaran; J. Yun; B. Zhang; J. Zhao; Z. Zhou

    2001-10-01

    The differential cross section, d{sigma}/dt, for p0 meson photoproduction on the proton above the resonance region was measured up to a momentum transfer -t = 5 GeV2 using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The p0 channel was extracted from the measured two charged-pion cross sections by fitting the {pi}+{pi}- and p{pi}+ invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large -t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe p photoproduction.

  3. Sunlight-induced degradation of fluoroquinolones in wastewater effluent: Photoproducts identification and toxicity.

    PubMed

    Sturini, Michela; Speltini, Andrea; Maraschi, Federica; Pretali, Luca; Ferri, Elida Nora; Profumo, Antonella

    2015-09-01

    The photodegradation of Ciprofloxacin (CIP), Enrofloxacin (ENR), Danofloxacin (DAN), Marbofloxacin (MAR) and Levofloxacin (LEV), five widely used fluoroquinolones (FQs), was studied in urban WWTP secondary effluent, under solar light. The degradation profiles and the kinetic constants were determined at the micrograms per litre levels (20-50 μg L(-1)). The photo-generated products were identified by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The toxicity of the photoproducts was assessed by Vibrio fischeri light emission inhibition assay performed on irradiated and not-irradiated FQs solutions, at environmentally significant concentrations. Attention was focused on the evaluation of the photoproducts contribution to the overall biotoxic effect of these emerging pollutants. Data from chronic exposure experiments (24-48 h) were primarily considered. Results confirmed the major usefulness of chronic toxicity data with respect to the acute assay ones and proved the not negligible biotoxicity of the FQs photodegradation products.

  4. Thymine photodimer formation in DNA hairpins. Unusual conformations favor (6 - 4) vs. (2 + 2) adducts.

    PubMed

    Hariharan, Mahesh; Siegmund, Karsten; Saurel, Clifton; McCullagh, Martin; Schatz, George C; Lewis, Frederick D

    2014-02-01

    The photochemical reactions of eleven synthetic DNA hairpins possessing a single TT step either in a base-paired stem or in a hexanucleotide linker have been investigated. The major reaction products have been identified as the cis-syn (2 + 2) adduct and the (6 - 4) adduct on the basis of their spectroscopic properties including 1D and 2D NMR spectra, UV spectra and stability or instability to photochemical cleavage. Product quantum yields and ratios determined by HPLC analysis allow the behaviour of the eleven hairpins to be placed into three groups: Group I in which the (2 + 2) adduct is the major product, as is usually the case for DNA, Group II in which comparable amounts of (2 + 2) and (6 - 4) adducts are formed, and Group III in which the major product is the (6 - 4) adduct. The latter behaviour is without precedent in natural or synthetic DNA and appears to be related to the highly fluxional structures of the hairpin reactants. Molecular dynamics simulation of ground state conformations provides quantum yields and product ratios calculated using a single parameter model that are in reasonable agreement with most of the experimental results. Factors which may influence the observed product ratios are discussed.

  5. Single Chirality (6,4) Single-Walled Carbon Nanotubes for Fluorescence Imaging with Silicon Detectors.

    PubMed

    Antaris, Alexander L; Yaghi, Omar K; Hong, Guosong; Diao, Shuo; Zhang, Bo; Yang, Jiang; Chew, Leila; Dai, Hongjie

    2015-12-16

    Postsynthetic single-walled carbon nanotube (SWCNT) sorting methods such as density gradient ultracentrifugation, gel chromatography, and electrophoresis have all been inspired by established biochemistry separation techniques designed to separate subcellular components. Biochemistry separation techniques have been refined to the degree that parameters such as pH, salt concentration, and temperature are necessary for a successful separation, yet these conditions are only now being applied to SWCNT separation methodologies. Slight changes in pH produce radically different behaviors of SWCNTs inside a density gradient, allowing for the facile separation of ultrahigh purity (6,4) SWCNTs from as-synthesized carbon nanotubes. The (6,4) SWCNTs are novel fluorophores emitting below ≈900 nm and can be easily detected with conventional silicon-based charge-coupled device detectors without the need for specialized InGaAs cameras. The (6,4) SWCNTs are used to demonstrate their potential as a clinically relevant NIR-I fluorescence stain for the immunohistochemical staining of cells and cancer tissue sections displaying high endothelial growth factor receptor levels.

  6. Exclusive Photoproduction of K+Σ*-(n) Off Deuteron

    SciTech Connect

    Lu, Haiyun; Graham, Lewis; Zhao, Zhiwen; Park, Kijun; Gothe, Ralf

    2010-08-16

    We are using the CEBAF Large Acceptance Spectrometer (CLAS) to study the exclusive photoproduction of K+Σ*- (1385) off the deuteron. It will be the first published total cross section of this reaction channel. We show the preliminary results of the total cross section, while we present all the key steps of achieving it. In order to study the reaction mechanism, we also study and show the angular distribution in the Gottfried-Jackson frame.

  7. Photoproduction of the eta prime meson in the effective Lagrangian approach

    SciTech Connect

    Mukhopadhyay, N.C.; Zhang, J.F.; Benmerrouche, M.

    1994-04-01

    In the framework of the effective Lagrangian approach, the authors study the {eta}{prime} photoproduction off protons, of great interest at CEBAF I and II. They calculate the contributions from the leading nucleon Born terms, vector meson exchanges, and estimate the resonance contributions, using the transition amplitudes from the recent quark model estimates by Capstick and Roberts. They discuss implications for the CEBAF experiments.

  8. Exclusive photoproduction of a γ ρ pair with a large invariant mass

    NASA Astrophysics Data System (ADS)

    Boussarie, R.; Pire, B.; Szymanowski, L.; Wallon, S.

    2017-02-01

    Exclusive photoproduction of a γ ρ pair in the kinematics where the pair has a large invariant mass and the final nucleon has a small transverse momentum is described in the collinear factorization framework. The scattering amplitude is calculated at leading order in α s and the differential cross sections for the process where the ρ-meson is either longitudinally or transversely polarized are estimated in the kinematics of the JLab 12-GeV experiments.

  9. Anomaly in the KS0Σ+ photoproduction cross section off the proton at the K* threshold

    NASA Astrophysics Data System (ADS)

    CBELSA/TAPS Collaboration; Ewald, R.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Brinkmann, K.-T.; Crede, V.; Dutz, H.; Elsner, D.; Fornet-Ponse, K.; Frommberger, F.; Funke, Ch.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Hannappel, J.; Hoffmeister, P.; Jaegle, I.; Jahn, O.; Jude, T.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L.; van Pee, H.; Roy, A.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.

    2012-07-01

    The γ+p→K0+Σ+ photoproduction reaction is investigated in the energy region from threshold to Eγ=2250 MeV. The differential cross section exhibits increasing forward-peaking with energy, but only up to the K* threshold. Beyond, it suddenly returns to a flat distribution with the forward cross section dropping by a factor of four. In the total cross section a pronounced structure is observed between the K*Λ and K*Σ thresholds.

  10. Beam asymmetries in near-threshold ω photoproduction off the proton

    NASA Astrophysics Data System (ADS)

    Klein, Frank; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fuchs, M.; Funke, Ch.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Morales, C.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Radkov, A.; Roy, A.; Sarantsev, A. V.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.

    2008-12-01

    The photoproduction of ω mesons off protons has been studied at the Bonn ELSA accelerator from threshold to Eγ=1700MeV. Linearly polarized beams were produced via coherent bremsstrahlung. Large photon asymmetries in excess of 50% were obtained. For the first time the pion asymmetries associated with the ω→π0γ decay were measured and found close to zero. The asymmetries indicate s-channel resonance formation on top of t-channel exchange processes.

  11. Polarization Observables From The Photoproduction Of Omega-Mesons Using Linearly Polarized Photons

    SciTech Connect

    Martinez, Danny; Cole, Philip L.

    2014-01-01

    We report on the extraction of Polarization Observables Spin Density Matrix Elements (SDMEs), and Beam Asymmetry Sigma for omega meson photoproduction using a beam of linearly polarized photons in the photon energy region of Egamma = 1.3 to 1.7 GeV, by means of the angular distributions of the daughter pions from omega decay. These preliminary results are from the g8b dataset, which were collected with the CLAS detector in Hall B of Jefferson Lab.

  12. Amplitude reconstruction from complete photoproduction experiments and truncated partial-wave expansions

    DOE PAGES

    Workman, R. L.; Tiator, L.; Wunderlich, Y.; ...

    2017-01-19

    Here, we compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the photoproduction of pseudoscalar mesons. The approach is pedagogical, showing in detail how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles).

  13. Measurement of the G double-polarisation observable in pion photoproduction

    SciTech Connect

    J. McAndrew, D. Watts, E. Pasyuk

    2012-04-01

    The g9a experiment using the CLAS detector in Hall B of Jefferson Lab will measure double-polarization observables using a polarized energy-tagged photon beam in conjunction with the frozen spin target, FROST. This contribution describes the extraction of the G double polarization observable in the single pion photoproduction using a linearly polarized photon beam in the energy range 730-2300 MeV and the longitudinally polarized frozen spin target, FROST.

  14. Prompt photon photoproduction at HERA with non-collinear parton dynamics

    SciTech Connect

    Lipatov, A. V.; Zotov, N. P.

    2011-07-15

    We investigate the prompt photon photoproduction at HERA within the framework of the k{sub T}-factorization approach to QCD. Our consideration is based on the off-shell matrix elements for the underlying partonic subprocesses and the Kimber-Martin-Ryskin (KMR) unintegrated parton densities in the proton. We also use the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) unintegrated gluon as well as valence and sea quark distributions.

  15. Test of factorization in diffractive deep inelastic scattering and photoproduction at HERA

    SciTech Connect

    Polifka, Richard

    2015-04-10

    The QCD factorization theorem in diffraction is tested by comparing diffractive jet production data to QCD predictions based on fits to inclusive diffractive cross section data. H1 measured dijet production with a leading proton detected in the Very Forward Proton Spectrometer (VFPS), both in deep-inelastic scattering and in photoproduction. The DIS measurements are complemented by measurements of dijet production with an associated rapidity gap and in a data sample selected with a leading proton in the Forward Proton Spectrometer (FPS)

  16. A comparison of hydrogen photoproduction by sulfur-deprived Chlamydomonas reinhardtii under different growth conditions.

    PubMed

    Kosourov, Sergey; Patrusheva, Elena; Ghirardi, Maria L; Seibert, Michael; Tsygankov, Anatoly

    2007-03-10

    Continuous photoproduction of H(2) by the green alga, Chlamydomonas reinhardtii, is observed after incubating the cultures for about a day in the absence of sulfate and in the presence of acetate. Sulfur deprivation causes the partial and reversible inactivation of photosynthetic O(2) evolution in algae, resulting in the light-induced establishment of anaerobic conditions in sealed photobioreactors, expression of two [FeFe]-hydrogenases in the cells, and H(2) photoproduction for several days. We have previously demonstrated that sulfur-deprived algal cultures can produce H(2) gas in the absence of acetate, when appropriate experimental protocols were used (Tsygankov, A.A., Kosourov, S.N., Tolstygina, I.V., Ghirardi, M.L., Seibert, M., 2006. Hydrogen production by sulfur-deprived Chlamydomonas reinhardtii under photoautotrophic conditions. Int. J. Hydrogen Energy 31, 1574-1584). We now report the use of an automated photobioreactor system to compare the effects of photoautotrophic, photoheterotrophic and photomixotrophic growth conditions on the kinetic parameters associated with the adaptation of the algal cells to sulfur deprivation and H(2) photoproduction. This was done under the experimental conditions outlined in the above reference, including controlled pH. From this comparison we show that both acetate and CO(2) are required for the most rapid inactivation of photosystem II and the highest yield of H(2) gas production. Although, the presence of acetate in the system is not critical for the process, H(2) photoproduction under photoautotrophic conditions can be increased by optimizing the conditions for high starch accumulation. These results suggest ways of engineering algae to improve H(2) production, which in turn may have a positive impact on the economics of applied systems for H(2) production.

  17. Photoproduction of dissolved organic carbon and inorganic nutrients from resuspended lake sediments.

    PubMed

    Hu, Bin; Wang, Peifang; Zhang, Nannan; Wang, Chao; Ao, Yanhui

    2016-11-01

    Sediments exposed to simulated solar radiation can serve as an important source of dissolved organic carbon (DOC) to surrounding waters. However, it is still unclear if dissolved nutrients can be photoproduced from lake sedimentary organic matter. In this study, a series of laboratory-based experiments was conducted to address the photoproduction of dissolved inorganic nutrients and DOC from resuspended Taihu Lake sediments. Dissolved inorganic nutrients and DOC were photoproduced after 8-h irradiation. The released NH4(+), NOx(-), and DOC levels ranged from 3.57 to 12.14, 1.43 to 6.43, and 24.17 to 69.17 μmol L(-1), respectively. The variation in the amount released indicated that sediment source had an effect on DOC and nutrient photorelease. More DOC and nutrients were released from higher concentration suspensions. However, due to the light absorption by suspended sediment, less DOC and nutrients were released from per gram of suspended sediment in high concentration suspensions. The decrease in DOC and increase in dissolved inorganic nitrogen during the last 2-h irradiation indicated that the photoproduction of inorganic nutrients proceeded via direct photodissolution of suspended sediments and subsequent photodegradation of the produced dissolved organic matter. Our results demonstrated that the photoproduction flux of NH4(+) and NOx(-) accounts for 12.3 and 6.5 % of wet deposition, respectively, which suggest that the photodissolution of suspended sediment could be a potential source of DOC and dissolved nutrients in shallow water ecosystems.

  18. Phage display of ScFv peptides recognizing the thymidine(6–4)thymidine photoproduct

    PubMed Central

    Zavala, Anamaria G.; Lancaster, Thaddeus; Groopman, John D.; Strickland, Paul T.; Chandrasegaran, Srinivasan

    2000-01-01

    Solar ultraviolet (UV) radiation induces DNA photoproducts in skin cells and is the predominant cause of human skin cancers. To understand human susceptibility to skin cancer and to facilitate the development of prevention measures, highly specific reagents to detect and quantitate UV-induced DNA adducts in human skin will be needed. One approach towards this end is the use of monoclonal antibody-based molecular dosimetry methods. To facilitate the development of photoproduct-specific antibody reagents we have: (i) cloned and sequenced a single chain variable fragment (ScFv) gene coding for one such high affinity monoclonal antibody, αUVssDNA-1 (mAb C3B6), recognizing the thymidine(6–4)thymidine photoproduct; (ii) expressed and displayed the cloned ScFv gene on the surface of phage; (iii) selected functional recombinant phage by panning; (iv) purified the ScFv peptide; (v) shown that the purified ScFv peptide binds to UV-irradiated polythymidylic acid but not unirradiated polythymidylic acid. This is the first demonstration of the use of phage display to select a ScFv recognizing DNA damage. In addition, this is the initial step towards immortalizing the antibody gene for genetic manipulation, structure–function studies and application to human investigations. PMID:10710441

  19. Photodegradation of aqueous argatroban investigated by LC/MS(n): Photoproducts, transformation processes and potential implications.

    PubMed

    Secrétan, Philippe-Henri; Karoui, Maher; Bernard, Mélisande; Ghermani, Noureddine; Safta, Fathi; Yagoubi, Najet; Do, Bernard

    2016-11-30

    Argatroban (ARGA), used as intravenous anticoagulant drug, has been reported to photodegrade under light exposure, requiring specific precautions at handling, storage and administration. Thus, for the first time, aqueous ARGA photodegradation under aerobic conditions has been described in terms of photoproducts, phototransformation processes and potential implications. ARGA significant photoproducts were successfully separated and characterized by gradient reversed-phase liquid chromatography coupled with high-resolution multistage mass spectrometry (LC/HR-MS(n)). Hitherto still not available in literature, ARGA in-depth fragmentation study was conducted so as to thoroughly sort out the main mechanisms specific to the molecule and therefore, to propose a fragmentation pattern relevant to the identification of ARGA related substances. Thereafter, in view of the structural characteristics of the photoproducts formed, ARGA photodegradation pathways could be worked out, showing that whether by direct photolysis or through photosensitization, the methyltetrahydroquinoline nitrogen and that of guanidine group would be mainly involved in photolysis initiation reactions, through one-electron oxidation along with proton loss. Desulfonation, cyclisation affording compounds of diazinane type, and/or rearrangements with transfer of the methyltetrahydroquinoline group toward the guanidine function were observed accordingly. Having a good insight into ARGA photodegradation pathways allows for consistent measures in view of mitigating or avoiding the drug decay and the related potential effects.

  20. Biological activity of photoproducts of merocyanine 540 generated by laser-light activation

    NASA Astrophysics Data System (ADS)

    Gulliya, Kirpal S.; Chanh, Tran C.; Pervaiz, Shazib; Harriman, Anthony; Matthews, James Lester

    1992-08-01

    Controlled exposure of photoactive compounds to light prior to their use in biological targets results in the formation of heretofore unknown photoproducts. This process of photoproduct generation, termed "preactivation," renders the photactive compound capable of systemic use without further dependence on light. Preactivation of mercyanin 540 (MC540) and several other photoactive compounds is achievable by exposure to CW and pulse laser radiation. The singlet oxygen generated at excited states attacks the dye molucule itself, resulting in the formation of biologically active photoproducts. For preactivated MC540 (photoproducts of MC540) generated by exposure to argon laser light (514 nm) and light from free-electron laser, we have demonstrated its effectiveness in selective killing of certain types of cultured tumor cells as well as human immunodeficiency virus type 1 (HIV-1) with very low, if any, damage to normal cells and tisues. For example, approximately 90% of the Burkitt's lymphoma Daudi cells and HL-60 leukemic cells are killed by preactivated MC540 at a concentration of 120 μg/ml. A two-hour treatment of cultured cells with buthionine sulfoxamine followed by the treatement with preactivated MC540 reults in 99.99% inhibition of clonogenic tumor stem cell growth. We also have demonstrated that preactivated MC540 is very effective in killing cell-free and cell-associated HIV-1. It also is very effective in killing HIV-1 and simian immunodeficiency virus (SIV) in virus-infected blood in vitro as determined by reverse transcriptase, P24, P17, core antigen expression and synctium formation. Treatment of HIV-1 with preactivated MC540 renders the treated HIV-1 incapable of binding to CD4 target molecules on T cells as determined by immunofluorescence and radioimmunoprecipitation assays. In vivo toxicology studies show that preactivated MC540 is very well tolerated and does not produce any signs of adverse reaction at the therapeutic doses, as determined by

  1. Energetics of Photoinduced Charge Migration within the Tryptophan Tetrad of an Animal (6-4) Photolyase.

    PubMed

    Cailliez, Fabien; Müller, Pavel; Firmino, Thiago; Pernot, Pascal; de la Lande, Aurélien

    2016-02-17

    Cryptochromes and photolyases are flavoproteins that undergo cascades of electron/hole transfers after excitation of the flavin cofactor. It was recently discovered that animal (6-4) photolyases, as well as animal cryptochromes, feature a chain of four tryptophan residues, while other members of the family contain merely a tryptophan triad. Transient absorption spectroscopy measurements on Xenopus laevis (6-4) photolyase have shown that the fourth residue is effectively involved in photoreduction but at the same time could not unequivocally ascertain the final redox state of this residue. In this article, polarizable molecular dynamics simulations and constrained density functional theory calculations are carried out to reveal the energetics of charge migration along the tryptophan tetrad. Migration toward the fourth tryptophan is found to be thermodynamically favorable. Electron transfer mechanisms are sought either through an incoherent hopping mechanism or through a multiple sites tunneling process. The Jortner-Bixon formulation of electron transfer (ET) theory is employed to characterize the hopping mechanism. The interplay between electron transfer and relaxation of protein and solvent is analyzed in detail. Our simulations confirm that ET in (6-4) photolyase proceeds out of equilibrium. Multiple site tunneling is modeled with the recently proposed flickering resonance mechanism. Given the position of energy levels and the distribution of electronic coupling values, tunneling over three tryptophan residues may become competitive in some cases, although a hopping mechanism is likely to be the dominant channel. For both reactive channels, computed rates are very sensitive to the starting protein configuration, suggesting that both can take place and eventually be mixed, depending on the state of the system when photoexcitation takes place.

  2. Optical properties of the (3.4.6.4) hexagonal Archimedean photonic crystal

    NASA Astrophysics Data System (ADS)

    Jovanović, Djordje; Gajić, Radoš

    2011-01-01

    We theoretically investigated the optical properties of the lesser known (3.4.6.4) Archimedean photonic crystal. The structure is two dimensional and made of dielectric GaAs rods in air. The calculations of the band structures, equifrequency contours, and simulations of the wave propagation through the structure were performed by the plane wave expansion and finite-difference time-domain methods. With analysis of the gap map and equifrequency contours we obtained frequency ranges for best performance for wave guiding. For those frequency ranges, we designed a new type of waveguide for possible applications in integrated optics. In addition, negative refraction was exhibited by the structure.

  3. An alternative eukaryotic DNA excision repair pathway.

    PubMed Central

    Freyer, G A; Davey, S; Ferrer, J V; Martin, A M; Beach, D; Doetsch, P W

    1995-01-01

    DNA lesions induced by UV light, cyclobutane pyrimidine dimers, and (6-4)pyrimidine pyrimidones are known to be repaired by the process of nucleotide excision repair (NER). However, in the fission yeast Schizosaccharomyces pombe, studies have demonstrated that at least two mechanisms for excising UV photo-products exist; NER and a second, previously unidentified process. Recently we reported that S. pombe contains a DNA endonuclease, SPDE, which recognizes and cleaves at a position immediately adjacent to cyclobutane pyrimidine dimers and (6-4)pyrimidine pyrimidones. Here we report that the UV-sensitive S. pombe rad12-502 mutant lacks SPDE activity. In addition, extracts prepared from the rad12-502 mutant are deficient in DNA excision repair, as demonstrated in an in vitro excision repair assay. DNA repair activity was restored to wild-type levels in extracts prepared from rad12-502 cells by the addition of partially purified SPDE to in vitro repair reaction mixtures. When the rad12-502 mutant was crossed with the NER rad13-A mutant, the resulting double mutant was much more sensitive to UV radiation than either single mutant, demonstrating that the rad12 gene product functions in a DNA repair pathway distinct from NER. These data directly link SPDE to this alternative excision repair process. We propose that the SPDE-dependent DNA repair pathway is the second DNA excision repair process present in S. pombe. PMID:7623848

  4. CFL3D Version 6.4-General Usage and Aeroelastic Analysis

    NASA Technical Reports Server (NTRS)

    Bartels, Robert E.; Rumsey, Christopher L.; Biedron, Robert T.

    2006-01-01

    This document contains the course notes on the computational fluid dynamics code CFL3D version 6.4. It is intended to provide from basic to advanced users the information necessary to successfully use the code for a broad range of cases. Much of the course covers capability that has been a part of previous versions of the code, with material compiled from a CFL3D v5.0 manual and from the CFL3D v6 web site prior to the current release. This part of the material is presented to users of the code not familiar with computational fluid dynamics. There is new capability in CFL3D version 6.4 presented here that has not previously been published. There are also outdated features no longer used or recommended in recent releases of the code. The information offered here supersedes earlier manuals and updates outdated usage. Where current usage supersedes older versions, notation of that is made. These course notes also provides hints for usage, code installation and examples not found elsewhere.

  5. Next-to-next-to-leading order contributions to jet photoproduction and determination of αs

    NASA Astrophysics Data System (ADS)

    Klasen, Michael; Kramer, Gustav; Michael, Markus

    2014-04-01

    We present the first calculation of inclusive jet photoproduction with approximate next-to-next-to-leading-order contributions, obtained from a unified threshold resummation formalism. The leading coefficients for direct photoproduction are computed analytically. Together with the coefficients pertinent to parton-parton scattering, they are shown to agree with those appearing in our full next-to-leading-order calculations. For hadron-hadron scattering, numerical agreement is found with a previous calculation of jet production at the Tevatron. We show that the direct and resolved approximate next-to-next-to-leading-order contributions considerably improve the description of final ZEUS data on jet photoproduction and that the error on the determination of the strong coupling constant is significantly reduced.

  6. Antioxidant properties of flavone-6(4')-carboxaldehyde oxime ether derivatives.

    PubMed

    Ayhan-Kilcigil, Gülgün; Coban, Tülay; Tunçbilek, Meral; Can-Eke, Benay; Bozdağ-Dündar, Oya; Ertan, Rahmiye; Iscan, Mümtaz

    2004-06-01

    The in vitro antioxidant properties of some flavone-6(4)-carboxaldehyde oxime ether derivatives (Ia-f, IIa-f) were determined by their effects on the rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels by measuring the formation of 2-thiobarbituric acid reactive substances. The free radical scavenging properties of the compounds were also examined in vitro by determining their capacity to scavenge superoxide anions and interact with the stable free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The most active compounds, IIb (Flavone-4'-carboxaldehyde-O-ethyl oxime) and Id (Flavone-6-carboxaldehyde-O-[2-(1-pyrolidino) ethyl] oxime), caused 98 and 79% inhibition of superoxide anion production and DPPH stable free radical at 10(-3) M, respectively.

  7. Study of the Hyperon-Nucleon (YN) Interaction in Exclusive Λ Photoproduction off the Deuteron

    NASA Astrophysics Data System (ADS)

    Cao, Tongtong; Ilieva, Yordanka; Zachariou, Nicholas

    2016-07-01

    This study aims to extract the polarization observables Cx, Cz, ∑, Ox, and Oz for final-state interactions (FSI) in overrightarrow γ d to {K^ + }overrightarrow Λ n. The data were taken with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) during the E06-103 experiment. These are the very first results for FSI observables in hyperon photoproduction and are expected to constrain the free parameters of YN potentials. This work is funded in part by the U.S. NSF under grant PHY-125782.

  8. Near-threshold diffractive psi-meson photoproduction from the proton.

    PubMed

    Mibe, T; Chang, W C; Nakano, T; Ahn, D S; Ahn, J K; Akimune, H; Asano, Y; Daté, S; Ejiri, H; Fujimura, H; Fujiwara, M; Hicks, K; Hotta, T; Imai, K; Ishikawa, T; Iwata, T; Kawai, H; Kim, Z Y; Kino, K; Kohri, H; Kumagai, N; Makino, S; Matsuda, T; Matsumura, T; Matsuoka, N; Miwa, K; Miyabe, M; Miyachi, Y; Morita, M; Muramatsu, N; Niiyama, M; Nomachi, M; Ohashi, Y; Ooba, T; Ohkuma, H; Oshuev, D S; Rangacharyulu, C; Sakaguchi, A; Sasaki, T; Shagin, P M; Shiino, Y; Shimizu, H; Sugaya, Y; Sumihama, M; Titov, A I; Toi, Y; Toyokawa, H; Wakai, A; Wang, C W; Wang, S C; Yonehara, K; Yorita, T; Yoshimura, M; Yosoi, M; Zegers, R G T

    2005-10-28

    Photoproduction of a phi meson on protons was studied by means of linearly polarized photons at forward angles in the low-energy region from threshold to Egamma = 2.37 GeV. The differential cross sections at t = -|t|min do not increase smoothly as Egamma increases but show a local maximum at around 2.0 GeV. The angular distributions demonstrate that phi mesons are photoproduced predominantly by helicity-conserving processes, and the local maximum is not likely due to unnatural-parity processes.

  9. Augmentation of H2 photoproduction in Rhodopseudomonas palustris by N-heterocyclic aromatic compounds.

    PubMed

    Archana, A; Sasikala, Ch; Ramana, Ch V

    2003-01-01

    Increases of 23- (5.6 mmol acetylene reduced mg dry wt(-1)) and 16- (4 mmol acetylene reduced mg dry wt(-1)) fold in nitrogenase activity and 12- (671 microl H2 mg dry wt(-1) h(-1)) and 6- (349 microl mg dry wt(-1) h(-1)) fold in H2 photoproduction in Rhodopseudomonas palustris JA1 over 24 h were achieved with pyrazine 2-carboxylate (3 mM) and 3-picoline (3 mM), respectively, and were higher than earlier reports of enhancement (1.5 to 5-fold) in biological H2 production using various alternative methods.

  10. Precise photoproduction of the charged top-pions at the LHC with forward detector acceptances

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Yue, Chong-Xing

    2014-04-01

    We study the photoproduction of the charged top-pion predicted by the top triangle moose (TTM) model (a deconstructed version of the topcolor-assisted technicolor TC2 model) via the processes at the 14 TeV Large Hadron Collider (LHC) including next-to-leading order (NLO) QCD corrections. Our results show that the production cross sections and distributions are sensitive to the free parameters and . A typical QCD correction value is and this does not depend much on as well as the forward detector acceptances.

  11. Photoproduction of the Charged Top-Pions at the LHeC

    NASA Astrophysics Data System (ADS)

    Guo, Jing; Yue, Chong-Xing; Zhang, Jiao; Zeng, Qing-Guo

    2012-11-01

    The top triangle moose (TTM) model, which can be seen as the deconstructed version of the topcolor-assisted technicolor (TC2) model, predicts the existence of the charged top-pions πt± in low energy spectrum. In the context of this model, we consider photoproduction of πt± via the subprocesses γb → tπt- and at the large hadron-electron collider (LHeC), in which high energy photon beams are generated by using the Compton backscatting method. We find that, as long as the charged top-pions are not too heavy, they can be abundantly produced via 76 collision.

  12. Effects of the Consistent Interaction on Kaon Photoproduction with Spin 5/2 Nucleon Resonances

    NASA Astrophysics Data System (ADS)

    Clymton, S.; Mart, T.

    2016-08-01

    Theoretical models for kaon photoproduction with spin 5/2 nucleon resonances have been plagued with the problem of interaction consistency. A number of studies predicted that a model with a consistent interaction leads to a better agreement with data. In this study a model with consistent interaction (model 2) is compared to the old model, which utilizes an inconsistent interaction (model 1), as well as to experimental data. The unknown parameters in scattering amplitude are extracted from fitting to 7400 experimental data points. This is performed by minimizing the X2/N value. It is found that model with a consistent interaction (model 2) is more suitable for explaining experimental data.

  13. Studying the Pc(4450) resonance in J/ψ photoproduction off protons

    DOE PAGES

    Blin, A. N. Hiller; Fernandez-Ramirez, C.; Jackura, A.; ...

    2016-08-01

    In this study, a resonance-like structure, the Pc(4450), has recently been observed in the J/ψ p spectrum by the LHCb collaboration. We discuss the feasibility of detecting this structure in J/ψ photoproduction in the CLAS12 experiment at JLab. We present a first estimate of the upper limit for the branching ratio of the Pc(4450) to J/ψ p. Our estimates, which take into account the experimental resolution effects, lead to a sizable cross section close to the J/ψ production threshold, which makes future experiments covering this region very promising.

  14. Inclusive Sigma- photoproduction on the neutron via the reaction gamma n (p) ---> K+ Sigma- (p)

    SciTech Connect

    Jorn Langheinrich; Ana Lima; Barry Berman

    2006-06-01

    The analysis described here is part of a comprehensive survey of the elementary strangeness photoproduction cross sections on the nucleon. The six elementary strangeness reactions are {gamma}n {yields} K{sup 0}{Lambda} and {gamma}p {yields} K{sup +}{Lambda} {gamma}n {yields} K{sup 0}{Sigma}{sup 0} and {gamma}p {yields} K{sup +}{Sigma}{sup 0} {gamma}n {yields} K{sup +}{Sigma}{sup -} and {gamma}p {yields} K{sup 0}{Sigma}|{sup +}

  15. The GlueX experiment: Search for gluonic excitations via photoproduction at Jefferson Lab

    SciTech Connect

    Eugenio, Paul

    2013-07-01

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenological models for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by an overview of the progress at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  16. Mm/submm Study of Gas-Phase Photoproducts from Methanol Interstellar Ice Analogues

    NASA Astrophysics Data System (ADS)

    Mesko, AJ; Smith, Houston Hartwell; Milam, Stefanie N.; Widicus Weaver, Susanna L.

    2016-06-01

    Icy grain reactions have gained quite the popularity in the astrochemistry community to explain the formation of complex organic molecules. Through temperature programmed desorption and photolysis experiments we use rotational spectroscopy to measure the gas-phase products of icy grain reactions. Previous results include testing detection limits of the system by temperature programmed desorption of methanol and water ices, photochemistry of gas-phase methanol, and detection of photodesorbed water from a pure water ice surface. Current work that will be discussed focuses on the detection of gas-phase CO and other photoproducts from an ice surface.

  17. A new measurement of Beam Asymmetry in Pion Photoproduction from the Neutron using CLAS

    SciTech Connect

    D. Sokhan, D. Watts, D. Branford, F. Klein

    2010-08-01

    We present a preliminary analysis of the photon beam asymmetry observable (Sigma) from the photoproduction reaction channel gamma+ n -> p + pi-. This new data was obtained using the near-4pi CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory, USA, employing a linearly polarised photon beam with an energy range 1.1 - 2.3 GeV. The measurement will provide new data to address the poorly established neutron excitation spectrum and will greatly expand the sparse world data-set both in energy and angle.

  18. High-power MIXSEL: an integrated ultrafast semiconductor laser with 6.4 W average power.

    PubMed

    Rudin, B; Wittwer, V J; Maas, D J H C; Hoffmann, M; Sieber, O D; Barbarin, Y; Golling, M; Südmeyer, T; Keller, U

    2010-12-20

    High-power ultrafast lasers are important for numerous industrial and scientific applications. Current multi-watt systems, however, are based on relatively complex laser concepts, for example using additional intracavity elements for pulse formation. Moving towards a higher level of integration would reduce complexity, packaging, and manufacturing cost, which are important requirements for mass production. Semiconductor lasers are well established for such applications, and optically-pumped vertical external cavity surface emitting lasers (VECSELs) are most promising for higher power applications, generating the highest power in fundamental transverse mode (>20 W) to date. Ultrashort pulses have been demonstrated using passive modelocking with a semiconductor saturable absorber mirror (SESAM), achieving for example 2.1-W average power, sub-100-fs pulse duration, and 50-GHz pulse repetition rate. Previously the integration of both the gain and absorber elements into a single wafer was demonstrated with the MIXSEL (modelocked integrated external-cavity surface emitting laser) but with limited average output power (<200 mW). We have demonstrated the power scaling concept of the MIXSEL using optimized quantum dot saturable absorbers in an antiresonant structure design combined with an improved thermal management by wafer removal and mounting of the 8-µm thick MIXSEL structure directly onto a CVD-diamond heat spreader. The simple straight cavity with only two components has generated 28-ps pulses at 2.5-GHz repetition rate and an average output power of 6.4 W, which is higher than for any other modelocked semiconductor laser.

  19. Quasi-free photoproduction of η-mesons off the deuteron

    NASA Astrophysics Data System (ADS)

    Jaegle, I.; Krusche, B.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dieterle, M.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, C.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Keshelashvili, I.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Maghrbi, Y.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nikonov, V. A.; Nanova, M.; Novinski, D. V.; Novotny, R.; Oberle, M.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Pheron, F.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, C.; Werthmüller, D.; Witthauer, L.

    2011-08-01

    Precise data for quasi-free photoproduction of η-mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5GeV. The η-mesons have been detected in coincidence with recoil protons and neutrons. Possible nuclear effects like Fermi motion and re-scattering can be studied via a comparison of the quasi-free reaction off the bound proton to η-production off the free proton. No significant effects beyond the folding of the free cross-section with the momentum distribution of the bound protons have been found. These Fermi motion effects can be removed by an analysis using the invariant mass of the η-nucleon pairs reconstructed from the final-state four-momenta of the particles. The total cross-section for quasi-free η-photoproduction off the neutron reveals even without correction for Fermi motion a pronounced bump-like structure around 1GeV of incident photon energy, which is not observed for the proton. This structure is even narrower in the invariant-mass spectrum of the η-neutron pairs. Position and width of the peak in the invariant-mass spectrum are W ≈ 1665 MeV and FWHM Γ ≈ 25 MeV. The data are compared to the results of different models.

  20. First measurement of direct $f_0(980)$ photoproduction on the proton

    SciTech Connect

    Battaglieri, Marco; De Vita, Raffaella; Szczepaniak, Adam

    2009-03-01

    We report on the results of the first measurement of exclusive $f_0(980)$ meson photoproduction on protons for $E_\\gamma=3.0 - 3.8$ GeV and $-t = 0.4-1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the $\\pi^+ \\pi^-$ channel by performing a partial wave analysis of the reaction $\\gamma p \\to p \\pi^+ \\pi^-$. Clear evidence of the $f_0(980)$ meson was found in the interference between $P$ and $S$ waves at $M_{\\pi^+ \\pi^-}\\sim 1$ GeV. The $S$-wave differential cross section integrated in the mass range of the $f_0(980)$ was found to be a factor of 50 smaller than the cross section for the $\\rho$ meson. This is the first time the $f_0(980)$ meson has been measured in a photoproduction experiment.

  1. Photochemistry and Photobiology of the Spore Photoproduct: A 50-Year Journey.

    PubMed

    Setlow, Peter; Li, Lei

    2015-11-01

    Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science, 149, 308-310], which was later named the spore photoproduct (SP). Formation of SP is due to the unique environment in the spore core that features low hydration levels favoring an A-DNA conformation, high levels of calcium dipicolinate that acts as a photosensitizer, and DNA saturation with small, acid-soluble proteins that alters DNA structure and reduces side reactions. In vitro studies reveal that any of these factors alone can promote SP formation; however, SP formation is usually accompanied by the production of other DNA photolesions. Therefore, the nearly exclusive SP formation in spores is due to the combined effects of these three factors. Spore photoproduct photoreaction is proved to occur via a unique H-atom transfer mechanism between the two involved thymine residues. Successful incorporation of SP into an oligonucleotide has been achieved via organic synthesis, which enables structural studies that reveal minor conformational changes in the SP-containing DNA. Here, we review the progress on SP photochemistry and photobiology in the past 50 years, which indicates a very rich SP photobiology that may exist beyond endospores.

  2. A multispecies study to assess the toxic and genotoxic effect of pharmaceuticals: furosemide and its photoproduct.

    PubMed

    Isidori, Marina; Nardelli, Angela; Parrella, Alfredo; Pascarella, Luigia; Previtera, Lucio

    2006-05-01

    Pharmaceutical products for humans and animals, as well as their related metabolites end up in the aquatic environment after use. Recent investigations show that concentrations of pharmaceuticals are detectable in the order of ng/l-mug/l in municipal wastewater, groundwater and also drinking water. Little is known about the effects, and the hazard of long-term exposure to low concentrations of pharmaceuticals for non-target aquatic organisms. This study was designed to assess the ecotoxicity of furosemide, a potent diuretic agent, and its photoproduct in the aquatic environment. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and chronic toxicity, while the SOS Chromotest and the Ames test were utilized to detect the genotoxic potential of the investigated compounds. A first approach to risk characterization was to calculate the environmental impact of furosemide by measured environmental concentration and predicted no effect concentration ratio (MEC/PNEC). To do so we used occurrence data reported in the literature and our toxicity results. The results showed that acute toxicity was in the order of mg/l for the crustaceans and absent for bacteria and rotifers. Chronic exposure to these compounds caused inhibition of growth population on the consumers, while the algae did not seem to be affected. A mutagenic potential was found for the photoproduct compared to the parental compound suggesting that byproducts ought to be considered in the environmental assessment of drugs. The risk calculated for furosemide suggested its harmlessness on the aquatic compartment.

  3. Toxic and genotoxic impact of fibrates and their photoproducts on non-target organisms.

    PubMed

    Isidori, Marina; Nardelli, Angela; Pascarella, Luigia; Rubino, Maria; Parrella, Alfredo

    2007-07-01

    Lipid regulators have been detected in effluents from sewage treatment plants and surface waters from humans via excretion. This study was designed to assess the ecotoxicity of fibrates, lipid regulating agents. The following compounds were investigated: Bezafibrate, Fenofibrate and Gemfibrozil and their derivatives obtained by solar simulator irradiation. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and chronic toxicity, while SOS Chromotest and Ames test were utilized to detect the genotoxic potential of the investigated compounds. The photoproducts were identified by their physical features and for the first risk evaluation, the environmental impact of parental compounds was calculated by Measured Environmental Concentrations (MEC) using the available data from the literature regarding drug occurrence in the aquatic environment and the Predicted No Effect Concentrations (PNEC) based on our toxicity data. The results showed that acute toxicity was in the order of dozens of mg/L for all the trophic levels utilized in bioassays (bacteria, rotifers, crustaceans). Chronic exposure to these compounds caused inhibition of growth population on rotifers and crustaceans while the algae seemed to be slightly affected by this class of pharmaceuticals. Genotoxic and mutagenic effects were especially found for the Gemfibrozil photoproduct suggesting that also byproducts have to be considered in the environmental risk of drugs.

  4. Differential Cross Sections of K0 Λ Photoproduction off the Deuteron

    NASA Astrophysics Data System (ADS)

    Compton, Nicholas; Taylor, Charles; Hicks, Kenneth; Cole, Phil; CLAS Collaboration Collaboration

    2017-01-01

    The investigation of nucleon resonances, N*, continues to be of great interest in order to understand non-perturbative solutions of QCD. Currently there are many poorly described or postulated spectroscopic states that need to be explored. Solving these problems entail the use of partial wave analyses (PWA) on photoproduction observables from both the proton and neutron. Photoproduction of strange mesons from the neutron are difficult to measure, and there are only a few measurements of this kind. These reactions supply essential complementary data to those on the proton. The differential cross section of γd ->K0 ΛX was measured, where the missing mass is constrained to be the spectator proton mass. This was done using data from the CLAS Collaboration at Jefferson Laboratory. Comparisons between the K+ Λ and K0 Λ cross sections demonstrate that the contribution typically associated with N(1900)3/2+ is less pronounced in the latter. This is possibly due to interference between the N* states and t-channel terms present in each reaction. A PWA fit from the BonnGa group, which incorporates known spectroscopic states in the complex energy plane, was used to study the contributions of various N* resonances.

  5. Photoproduction of vector mesons: from ultraperipheral to semi-central heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Kłusek-Gawenda, Mariola; Szczurek, Antoni

    2016-11-01

    We discuss nuclear cross sections for AA → AAV and AA → AAVV reactions with one or two vector mesons in the final state. Our analysis is done in the impact parameter space equivalent photon approximation. This approach allows to consider the above processes taking into account distance between colliding nuclei. We consider both ultraperipheral and semi-central collisions. We are a first group which undertook a study of single J/ψ photoproduction for different centrality bins. We show that one can describe new ALICE experimental data by including geometrical effects of collisions in the flux factor. Next, total and differential cross section for double-scattering mechanism in the exclusive AA → AAVV reaction in ultrarelativistic ultraperipheral heavy ion collisions is presented. In this context we consider double photoproduction and photon-photon processes. Simultaneously, we get very good agreement of our results with STAR (RHIC), CMS and ALICE (LHC) experimental data for single ρ0 and J/ψ vector meson production. A comparison of our predictions for exclusive four charged pions production is also presented.

  6. Photolysis of Antibiotics under Simulated Sunlight Irradiation: Identification of Photoproducts by High-Resolution Mass Spectrometry.

    PubMed

    Baena-Nogueras, Rosa María; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2017-02-28

    There is growing concern regarding the widespread use of antibiotics and their presence in the aqueous environment. Their removal in the water column is mediated by different types of degradation processes for which the mechanisms are still unclear. This research is focused on characterizing the photodegradation kinetics and pathways of two largely employed antibiotics families: sulfonamides (9 SDs) and fluoroquinolones (6 FQs). Degradation percentages and rates were measured in pure water exposed to simulated natural sunlight at a constant irradiance value (500 W m(-2)) during all the experiments, and the main photoproducts formed were characterized through accurate mass measurement using ultraperformance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-QToF-MS). Over 200 different phototransformation products were identified for SDs and FQs, 66% of them, to the best of our knowledge, have not been described before. Their sequential formation and disappearance over the course of the experiments reveals the existence of several pathways for the degradation of target antibiotics. Occurrence of new photoproducts derived from desulfonation and/or denitrification, as well as hydroxylation of photo-oxidized heterocyclic rings, have been identified during photodegradation of SDs, whereas a new pathway yielding oxidation of the benzene ring after the cleavage of the piperazine ring (e.g., CIP product with m/z 280) is described for FQs.

  7. Novel reagents for chemical cleavage at abasic sites and UV photoproducts in DNA.

    PubMed Central

    McHugh, P J; Knowland, J

    1995-01-01

    Hot piperidine is often used to cleave abasic and UV-irradiated DNA at the sites of damage. It can inflict non-specific damage on DNA, probably because it is a strong base and creates significant concentrations of hydroxyl ions which can attack purines and pyrimidines. We show that several other amines can cleave abasic DNA at or near neutral pH without non-specific damage. One diamine, N,N'-dimethylethylenediamine, efficiently cleaves abasic DNA at pH 7.4 by either beta- or beta,delta-elimination, depending on temperature. Using end-labelled oligonucleotides we show that cleavage depends mainly on elimination reactions, but that 4',5'-cyclization is also significant. This reagent also cleaves at photoproducts induced by UVC and UVB, producing the same overall pattern as piperidine, but with no non-specific damage. It should prove valuable in locating low levels of photoproducts in DNA, such as those induced by natural sunlight. Images PMID:7784169

  8. Resummation of Large Endpoint Corrections to Color-Octet J/psi Photoproduction

    SciTech Connect

    Sean Fleming; Adam K. Leibovich; Thomas Mehen

    2006-07-27

    An unresolved problem in J/{psi} phenomenology is a systematic understanding of the differential photoproduction cross section, d{sigma}/dz [{gamma} + p {yields} J/{psi} + X], where z = E{sub {psi}}/E{sub {gamma}} in the proton rest frame. In the non-relativistic QCD (NRQCD) factorization formalism, fixed-order perturbative calculations of color-octet mechanisms suffer from large perturbative and nonperturbative corrections that grow rapidly in the endpoint region, z {yields} 1. In this paper, NRQCD and soft collinear effective theory are combined to resum these large corrections to the color-octet photoproduction cross section. We derive a factorization theorem for the endpoint differential cross section involving the parton distribution function and the color-octet J/{psi} shape functions. A one loop matching calculation explicitly confirms our factorization theorem at next-to-leading order. Large perturbative corrections are resummed using the renormalization group. The calculation of the color-octet contribution to d{sigma}/dz is in qualitative agreement with data. Quantitative tests of the universality of color-octet matrix elements require improved knowledge of shape functions entering these calculations as well as resummation of the color-singlet contribution which accounts for much of the total cross section and also peaks near the endpoint.

  9. Hydrogen peroxide and superoxide photoproduction in diverse marine waters: A simple proxy for estimating direct CO2 photochemical fluxes

    NASA Astrophysics Data System (ADS)

    Powers, Leanne C.; Miller, William L.

    2015-09-01

    The photoproduction of H2O2 and CO2 exhibits a well-defined relationship with an average CO2:H2O2 molar ratio of 6.6 ± 1.8 as determined in a variety of marine waters ranging from a dark tidal creek to clear offshore stations near the Gulf Stream. Even when corrected for photobleaching, accumulation of both H2O2 and CO2 was not linear beyond 12 h of constant irradiation, with interval rates indicating that production efficiency for both products decreased with increasing photon dose. Direct measurements of O2- photoproduction, together with its dark thermal decay to H2O2, indicate that O2- may be the better proxy for photochemical dissolved organic matter oxidation to CO2. Given the very short irradiation times needed to determine O2- production rates (~2-5 min), determination of O2- photoproduction may provide robust estimates for initial CO2 photoproduction rates even in blue water, allowing greatly improved estimates for the global significance of dissolved organic carbon photooxidation.

  10. Significant Increase in Hydrogen Photoproduction Rates and Yields by Wild-Type Algae is Detected at High Photobioreactor Gas Phase Volume (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    This NREL Hydrogen and Fuel Cell Technical Highlight describes how hydrogen photoproduction activity in algal cultures can be improved dramatically by increasing the gas-phase to liquid-phase volume ratio of the photobioreactor. NREL, in partnership with subcontractors from the Institute of Basic Biological Problems in Pushchino, Russia, demonstrated that the hydrogen photoproduction rate in algal cultures always decreases exponentially with increasing hydrogen partial pressure above the culture. The inhibitory effect of high hydrogen concentrations in the photobioreactor gas phase on hydrogen photoproduction by algae is significant and comparable to the effect observed with some anaerobic bacteria.

  11. The Influence of Precipitation of Alpha2 on Properties and Microstructure in TIMETAL 6-4

    NASA Astrophysics Data System (ADS)

    Wu, Zhiwei; Qiu, Chunlei; Venkatesh, V.; Fraser, Hamish L.; Williams, R. E. A.; Viswanathan, G. B.; Thomas, Matthew; Nag, S.; Banerjee, Rajarshi; Loretto, Michael H.

    2013-04-01

    Samples of Hot Isostatically Pressed (HIPped) powder of TIMETAL 6-4 (Ti-6Al-4V, compositions in wt pct unless indicated), which was HIPped at 1203 K (930 °C), and of forged bar stock, which was slowly cooled from above the beta transus, were both subsequently held at 773 K (500 °C) for times up to 5 weeks and analyzed using scanning and transmission electron microscopy and atom probe analysis. It has been shown that in the samples aged for 5 weeks at 773 K (500 °C), there is a high density of alpha2 (α2, an ordered phase based on the composition Ti3Al) precipitates, which are typically 5 nm in size, and a significantly smaller density was present in the slowly cooled samples. The fatigue and tensile properties of samples aged for 5 weeks at 773 K (500 °C) have been compared with those of the HIPped powder and of the forged samples which were slowly cooled from just above the transus, and although no significant difference was found between the fatigue properties, the tensile strength of the aged samples was 5 pct higher than that of the as-HIPped and slowly cooled forged samples. The ductility of the forged samples did not decrease after aging at 773 K (500 °C) despite the strength increase. Transmission electron microscopy has been used to assess the nature of dislocations generated during tensile and fatigue deformation and it has been found that not just is planar slip observed, but dislocation pairs are not uncommon in samples aged at 773 K (500 °C) and some are seen in slowly cooled Ti6Al4V.

  12. Discovery of a 6.4 h black hole binary in NGC 4490

    NASA Astrophysics Data System (ADS)

    Esposito, P.; Israel, G. L.; Sidoli, L.; Mapelli, M.; Zampieri, L.; Motta, S. E.

    2013-12-01

    We report on the discovery with Chandra of a strong modulation (˜90 per cent pulsed fraction) at ˜6.4 h from the source CXOU J123030.3+413853 in the star-forming, low-metallicity spiral galaxy NGC 4490, which is interacting with the irregular companion NGC 4485. This modulation, confirmed also by XMM-Newton observations, is interpreted as the orbital period of a binary system. The spectra from the Chandra and XMM-Newton observations can be described by a power-law model with photon index Γ ˜ 1.5. During these observations, which span from 2000 November to 2008 May, the source showed a long-term luminosity variability by a factor of ˜5, between ˜2 × 1038 and 1.1 × 1039 erg s-1 (for a distance of 8 Mpc). The maximum X-ray luminosity, exceeding by far the Eddington limit of a neutron star, indicates that the accretor is a black hole. Given the high X-ray luminosity, the short orbital period and the morphology of the orbital light curve, we favour an interpretation of CXOU J123030.3+413853 as a rare high-mass X-ray binary system with a Wolf-Rayet star as a donor, similar to Cyg X-3. This would be the fourth system of this kind known in the local Universe. CXOU J123030.3+413853 can also be considered as a transitional object between high-mass X-ray binaries and ultraluminous X-ray sources (ULXs), the study of which may reveal how the properties of persistent black hole binaries evolve entering the ULX regime.

  13. A High-Resolution Study of the IGM at 5 < z < 6.4

    NASA Astrophysics Data System (ADS)

    Becker, G. D.; Sargent, W. L. W.; Rauch, M.; Simcoe, R. A.

    2005-12-01

    The complete Lyman-alpha absorption seen in the spectra of z > 6 quasars suggest that the reionization of the IGM may have completed as late as z = 6.2. However, this late reionization scenario remains controversial due in part to studies of galaxy luminosity functions, which favor a highly-ionized IGM out to z > 6.5. In order to improve our understanding of the IGM at these redshifts, we have acquired Keck/HIRES spectra of nine quasars at 4.8 < z < 6.4. These are the first high-resolution spectra ever taken at z > 4.6, and are providing the first detailed look at the very high-redshift IGM. We will present the first results from this data set, highlighting the evolution of the Lyman-alpha forest and the quasar proximity regions. The high-resolution data also reveal an overabundance of O I systems at z > 6 towards SDSS J1148+5251. These O I absorbers may represent the last pockets of neutral gas to be reionized at z ˜ 6. Alternatively, they may be caused by enriched galaxy halos physically similar to those observed at lower redshift. For these systems we are able to measure accurate column densities of O I, C II, and Si II. The relative abundances are consistent with the yields of ordinary Type II supernovae, with at most ˜ 30% of the silicon contributed by very massive stars. GDB and WLWS have been supported by the NSF through grants AST 99-00733 and AST 02-06067. MR has been supported by the NSF under grant AST 00-98492. RAS has been supported by the MIT Pappalardo Fellowship program.

  14. Maximizing the Hydrogen Photoproduction Yields in Chlamydomonas Reinhardtii Cultures: The Effect of the H2 Partial Pressure

    SciTech Connect

    Kosourov, S. N.; Batyrova, K. A.; Petushkova, E. P.; Tsygankov, A. A.; Ghirardi, M. L.; Seibert, M.

    2012-05-01

    Photoproduction of H{sub 2} gas has been examined in sulfur/phosphorus-deprived Chalmydomonas reinhardtii cultures, placed in photobioreactors (PhBRs) with different gas phase to liquid phase ratios (V{sub g.p.}/V{sub l.p.}). The results demonstrate that an increase in the ratio stimulates H{sub 2} photoproduction activity in both algal suspension cultures and in algae entrapped in thin alginate films. In suspension cultures, a 4x increase (from {approx}0.5 to {approx}2) in V{sub g.p.}/V{sub l.p} results in a 2x increase (from 10.8 to 23.1 mmol l{sup -1} or 264-565 ml l{sup -1}) in the total yield of H{sub 2} gas. Remarkably, 565 ml of H{sub 2} gas per liter of the suspension culture is the highest yield ever reported for a wild-type strain in a time period of less than 190 h. In immobilized algae, where diffusion of H{sub 2} from the medium to the PhBR gas phase is not affected by mixing, the maximum rate and yield of H{sub 2} photoproduction occur in PhBRs with V{sub g.p.}/V{sub l.p} above 7 or in a PhBR with smaller headspace, if the H{sub 2} is effectively removed from the medium by continuous flushing of the headspace with argon. These experiments in combination with studies of the direct inhibitory effect of high H{sub 2} concentrations in the PhBR headspace on H{sub 2} photoproduction activity in algal cultures clearly show that H{sub 2} photoproduction in algae depends significantly on the partial pressure of H{sub 2} (not O{sub 2} as previously thought) in the PhBR gas phase.

  15. Fluorescence of poly[2,6-(4-phenylquinoline)] and its blends

    NASA Astrophysics Data System (ADS)

    Lin, Hung-Sheng

    Optical absorption measurements and photoluminescence spectroscopy have been carried out on a class of nitrogen-containing pi-conjugated polymers which can be used as active materials in light emitting diodes. In this dissertation, Poly [2,6-(4-phenylquinoline)] (PPQ) was used as a model system to demonstrate that optical properties could be manipulated by inducing morphology changes in various PPQ-blends as well as by solvent interactions with the pi-conjugated backbone of the PPQ. It is shown that by controlling the preparation conditions, adding small molecules, and/or blending with other interactive polymers, the of the absorption and/or emission could be altered. Furthermore, it was found that both doping and chain packing may have important effects on the energy gap between the ground state and the excited state. There are two major peaks in the UV absorption spectrum of the PPQ. One peak is assigned to the phenyl group side chain, whereas the other one reflects the PPQ backbone, whose absorption has been illustrated to be dependent on experimental conditions. The position of the major photoluminescence emission peak was found to be influenced by (1) the nature of the solvent and the doping agents used, (2) different processing methods, and (3) blending with photo-inactive polymers such as Poly(vinyl alcohol) (PVA), Poly(ethylene oxide) (PEO), Poly(acrylic acid)(PAA), Sulfonic polystyrene (SPS), etc. These factors singly or in combination contribute to the shifting of the emission peak. In a polymer blend, the strength of the enthalpic interaction between its components determines the spatial separation of the polymers, which results in different morphologies in the blend, and in turn, different optical properties of the blend. Since the emission from a blend depends on its morphological dispersion, optical studies of polymer blends first involve control of morphologies in these blends. The morphologies of polymer blends have been studied by using Scanning

  16. Genome-wide analysis of human global and transcription-coupled excision repair of UV damage at single-nucleotide resolution

    PubMed Central

    Hu, Jinchuan; Adar, Sheera; Selby, Christopher P.

    2015-01-01

    We developed a method for genome-wide mapping of DNA excision repair named XR-seq (excision repair sequencing). Human nucleotide excision repair generates two incisions surrounding the site of damage, creating an ∼30-mer. In XR-seq, this fragment is isolated and subjected to high-throughput sequencing. We used XR-seq to produce stranded, nucleotide-resolution maps of repair of two UV-induced DNA damages in human cells: cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine–pyrimidone photoproducts [(6-4)PPs]. In wild-type cells, CPD repair was highly associated with transcription, specifically with the template strand. Experiments in cells defective in either transcription-coupled excision repair or general excision repair isolated the contribution of each pathway to the overall repair pattern and showed that transcription-coupled repair of both photoproducts occurs exclusively on the template strand. XR-seq maps capture transcription-coupled repair at sites of divergent gene promoters and bidirectional enhancer RNA (eRNA) production at enhancers. XR-seq data also uncovered the repair characteristics and novel sequence preferences of CPDs and (6-4)PPs. XR-seq and the resulting repair maps will facilitate studies of the effects of genomic location, chromatin context, transcription, and replication on DNA repair in human cells. PMID:25934506

  17. A gene for a Class II DNA photolyase from Oryza sativa: cloning of the cDNA by dilution-amplification.

    PubMed

    Hirouchi, T; Nakajima, S; Najrana, T; Tanaka, M; Matsunaga, T; Hidema, J; Teranishi, M; Fujino, T; Kumagai, T; Yamamoto, K

    2003-07-01

    Ultraviolet radiation induces the formation of two classes of photoproducts in DNA-the cyclobutane pyrimidine dimer (CPD) and the pyrimidine [6-4] pyrimidone photoproduct (6-4 product). Many organisms produce enzymes, termed photolyases, which specifically bind to these lesions and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. Two classes of photolyases (class I and class II) repair CPDs. A gene that encodes a protein with class II CPD photolyase activity in vitro has been cloned from several plants including Arabidopsis thaliana, Cucumis sativus and Chlamydomonas reinhardtii. We report here the isolation of a homolog of this gene from rice (Oryza sativa), which was cloned on the basis of sequence similarity and PCR-based dilution-amplification. The cDNA comprises a very GC-rich (75%) 5; region, while the 3; portion has a GC content of 50%. This gene encodes a protein with CPD photolyase activity when expressed in E. coli. The CPD photolyase gene encodes at least two types of mRNA, formed by alternative splicing of exon 5. One of the mRNAs encodes an ORF for 506 amino acid residues, while the other is predicted to code for 364 amino acid residues. The two RNAs occur in about equal amounts in O. sativa cells.

  18. Regge phenomenology of pion photoproduction off the nucleon at forward angles

    SciTech Connect

    Yu, Byung Geel; Choi, Tae Keun; Kim, W.

    2011-02-15

    We present a Regge model for pion photoproduction which is basically free of parameters within the framework of the s-channel helicity amplitude. For completeness we take into account axial mesons a{sub 1}(1260), b{sub 1}(1235) and tensor meson a{sub 2}(1320) in addition to the primary {pi}+{rho} exchanges for charged pion photoproduction, while the axial meson h{sub 1}(1170) exchange is added to the model of {omega}+{rho}{sup 0}+b{sub 1} exchanges for the neutral case. The present model deals for the first time with the a{sub 2} and h{sub 1} Regge poles in the s-channel helicity amplitude. For model independence, we use coupling constants of all exchanged mesons determined from empirical decay widths or from the SU(3) relations together with consistency check with existing estimates that are widely accepted in other reaction processes. Based on these coupling constants the simultaneous description of four photoproduction channels is given. Within the Regge regime, s>>4M{sup 2} and -t<2 GeV{sup 2}, cross sections and spin polarization asymmetries at various photon energies are analyzed and results are obtained in better agreement with experimental data without referring to any fitting procedure. The model confirms dominance of the nucleon Born term in the sharp rise of the charged pion cross section at very forward angles, while dominance of the {omega} exchange with the nonsense wrong signature zero leads to the deep dip in the neutral pion cross section. In contrast to existing models, however, our model for the charged pion case shows quite a different production mechanism due to the crucial role of the tensor meson a{sub 2} exchange in the cross section and spin polarization asymmetries. Also the axial meson b{sub 1} exchange is found to give a sizable contribution to the photon polarization asymmetry. In the neutral case, the role of the b{sub 1} is not significant, but the isoscalar h{sub 1} exchange gives an important contribution to the dip

  19. Photoproduction of ω mesons off nuclei and impact of polarization on the meson-nucleon interaction

    SciTech Connect

    Chudakov, Eugene A.; Gevorkyan, Sergey; Somov, Alexander

    2016-01-25

    We consider photoproduction of ω mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons σT = σ(VTN) can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the not-yet-measured total cross section for longitudinally polarized mesons σL = σ(VLN). The predictions for the latter strongly depend on the theoretical approaches. Furthermore, this work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designed to study the photoproduction of mesons in a large beam energy range up to 12 GeV.

  20. The Al Hoceima Mw 6.4 earthquake of 24 February 2004 and its aftershocks sequence

    NASA Astrophysics Data System (ADS)

    van der Woerd, Jérôme; Dorbath, Catherine; Ousadou, Farida; Dorbath, Louis; Delouis, Bertrand; Jacques, Eric; Tapponnier, Paul; Hahou, Youssef; Menzhi, Mohammed; Frogneux, Michel; Haessler, Henri

    2014-07-01

    The Al Hoceima Mw 6.4 earthquake of 24 February 2004 that occurred in the eastern Rif region of Morocco already hit by a large event in May 1994 (Mw 5.9) has been followed by numerous aftershocks in the months following the event. The aftershock sequence has been monitored by a temporary network of 17 autonomous seismic stations during 15 days (28 March-10 April) in addition to 5 permanent stations of the Moroccan seismic network (CNRST, SPG, Rabat). This network allowed locating accurately about 650 aftershocks that are aligned in two directions, about N10-20E and N110-120E, in rough agreement with the two nodal planes of the focal mechanism (Harvard). The aftershock alignments are long enough, about 20 km or more, to correspond both to the main rupture plane. To further constrain the source of the earthquake main shock and aftershocks (mb > 3.5) have been relocated thanks to regional seismic data from Morocco and Spain. While the main shock is located at the intersection of the aftershock clouds, most of the aftershocks are aligned along the N10-20E direction. This direction together with normal sinistral slip implied by the focal mechanism is similar with the direction and mechanisms of active faults in the region, particularly the N10E Trougout oblique normal fault. Indeed, the Al Hoceima region is dominated by an approximate ENE-SSW direction of extension, with oblique normal faults. Three major 10-30 km-long faults, oriented NNE-SSW to NW-SE are particularly clear in the morphology, the Ajdir and Trougout faults, west and east of the Al Hoceima basin, respectively, and the NS Rouadi fault 20 km to the west. These faults show clear evidence of recent vertical displacements during the late Quaternary such as uplifted alluvial terraces along Oued Rihs, offset fan surfaces by the Rouadi fault and also uplifted and tilted abandoned marine terraces on both sides of the Al Hoceima bay. However, the N20E direction is in contrast with seismic sources identified from

  1. A TeGM6-4r antigen-based immunochromatographic test (ICT) for animal trypanosomosis.

    PubMed

    Nguyen, Thu-Thuy; Ruttayaporn, Ngasaman; Goto, Yasuyuki; Kawazu, Shin-ichiro; Sakurai, Tatsuya; Inoue, Noboru

    2015-11-01

    Animal trypanosomosis is a disease that is distributed worldwide which results in huge economic losses due to reduced animal productivity. Endemic regions are often located in the countryside where laboratory diagnosis is costly or inaccessible. The establishment of simple, effective, and accurate field tests is therefore of great interest to the farming and veterinary sectors. Our study aimed to develop a simple, rapid, and sensitive immunochromatographic test (ICT) for animal trypanosomosis utilizing the recombinant tandem repeat antigen TeGM6-4r, which is conserved amongst salivarian trypanosome species. In the specificity analysis, TeGM6-4r/ICT detected all of Trypanosoma evansi-positive controls from experimentally infected water buffaloes. As expected, uninfected controls tested negative. All sera samples collected from Tanzanian and Ugandan cattle that were Trypanosoma congolense- and/or Trypanosoma vivax-positive by microscopic examination of the buffy coat were found to be positive by the newly developed TeGM6-4r/ICT, which was comparable to results from TeGM6-4r/ELISA (kappa coefficient [κ] = 0.78). TeGM6/ICT also showed substantial agreement with ELISA using Trypanosoma brucei brucei (κ = 0.64) and T. congolense (κ = 0.72) crude antigen, suggesting the high potential of TeGM6-4r/ICT as a field diagnostic test, both for research purposes and on-site diagnosis of animal trypanosomosis.

  2. Photoproduction of mesons off nuclei and in-medium modifications of hadrons

    NASA Astrophysics Data System (ADS)

    Krusche, Bernd

    2008-10-01

    During the last few years, the TAPS, Crystal Barrel, and Crystal Ball collaborations have investigated in-medium effects on hadrons at the MAMI accelerator in Mainz and the ELSA accelerator in Bonn in photon induced meson production reactions. There are many predictions that vector mesons change mass and width in dense and hot nuclear matter, due to partial chiral symmetry restoration. The predicted size of the effects is related to nuclear density and temperature, so that many efforts have been directed towards heavy ion collisions. However, the baryon density varies dramatically with time due to the formation and expansion of the `fireball', which complicates the interpretation. Furthermore, FSI effects are large, so that only meson decays into leptons (Dalitz-decays of ρ and φ mesons) could be used. In an alternative approach, photo-production of φ mesons from stable nuclei has been investigated at ELSA with the Crystal Barrel/TAPS setup. The φ mesons were identified via their ôγ decay. The advantages of this experiment are the much larger decay branching ratio (8.5% for φ->γô compared to 7x10-7 for φ->e^+e^-), the almost complete suppression of background from the ρ meson (ρ->γô decay branching ratio: 8x10-4) and the better control over experimental parameters like nuclear density. The experiment has for the first time directly established a downward shift of the φ-mass in nuclear matter via a comparison of the line shape of the φ invariant mass peak observed in photo-production off the free nucleon to the nuclear data. A detailed analysis of the scaling of the observed cross sections with nuclear mass number in the framework of different models has found an inelastic in-medium width of the φ meson in the range 130 - 150 MeV/c^2 at normal nuclear matter density for an average three-momentum of 1.1 GeV/c. Furthermore, a momentum dependent φN cross section in the range of 70 mb has been extracted. In the sector of scalar mesons, in a series of

  3. Photoproduction of J/ψ and ϒ in exclusive and proton dissociative diffractive events

    NASA Astrophysics Data System (ADS)

    Schäfer, Wolfgang; Cisek, Anna; Szczurek, Antoni

    2016-11-01

    We use a perturbative QCD based kT -factorization approach, to calculate the amplitude for the diffractive γp → Vp processes, where V is a J/ψ or ϒ ground state or excited vector meson. Using these amplitudes, we evaluate the cross section for exclusive photoproduction of J/ψ, ψ', ϒ mesons in proton-proton collisions. Calculations are performed for a variety of unintegrated gluon distributions, and we compare our results to LHCb data. Absorption effects are taken into account at the amplitude level. We also discuss the related diffractive production in proton dissociative events. Here we concentrate on electromagnetic dissociation , which is calculable without additional free parameters. Besides being of interest in their own right, dissociative events constitute an important experimental background to exclusive production.

  4. {phi}-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies

    SciTech Connect

    Salamanca, Julian; Cole, Philip L.

    2007-10-26

    The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how {phi}-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the {gamma}-vectorp{yields}{phi}p reaction, with {phi}{yields}K{sup +}K{sup -}, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.

  5. Φ-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies

    SciTech Connect

    Salamanca, Julian; Cole, Philip L

    2007-10-01

    The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how Φ-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the γp → Φp reaction, with Φ → K+K-, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.

  6. In vitro phototoxic properties of triamcinolone 16,17-acetonide and its main photoproducts.

    PubMed

    Miolo, Giorgia; Ricci, Andrea; Caffieri, Sergio; Levorato, Laura; Fasani, Elisa; Albini, Angelo

    2003-11-01

    The phototoxicity of triamcinolone 16,17-acetonide has been estimated through a panel of in vitro tests. The main target involved in phototoxicity induced by triamcinolone appeared to be the cell membrane. Oxygen-independent photohemolysis was observed. A photochemical study in water and buffered solutions supported the conclusion that this is related to the action of radicals formed upon UV irradiation (in particular UV-B) by Norrish Type-I fragmentation of the C-20 ketone group. Peroxy radicals were formed in the presence of oxygen and were the active species in that case. Three photoproducts, isolated from the photodegradation of the drug, were submitted to the same toxicity tests. Two of them were proved to possess toxic or phototoxic properties on erythrocytes, primarily induced by UV-B light, and may participate in the photosensitizing activity of triamcinolone 16,17-acetonide. Our in vitro results suggest that the drug can elicit weak photosensitizing properties in vivo.

  7. Prompt-photon plus jet associated photoproduction at HERA in the parton Reggeization approach

    NASA Astrophysics Data System (ADS)

    Kniehl, B. A.; Nefedov, M. A.; Saleev, V. A.

    2014-06-01

    We study the photoproduction of isolated prompt photons associated with hadron jets in the framework of the parton Reggeization approach. The cross section distributions in the transverse energies and pseudorapidities of the prompt photon and the jet as well as the azimuthal-decorrelation variables measured by the H1 and ZEUS collaborations at DESY HERA are nicely described by our predictions. The main improvements with respect to previous studies in the kT-factorization framework include the application of the Reggeized-quark formalism, the generation of exactly gauge-invariant amplitudes with off-shell initial-state quarks, and the exact treatment of the γR→γg box contribution with off-shell initial-state gluons.

  8. BFKL evolution and the growth with energy of exclusive J /Ψ and ϒ photoproduction cross sections

    NASA Astrophysics Data System (ADS)

    Bautista, I.; Fernandez Tellez, A.; Hentschinski, M.

    2016-09-01

    We investigate whether the Balitsky-Fadin-Kuraev-Lipatov (BFKL) low x evolution equation is capable to describe the energy dependence of the exclusive photo-production cross-section of vector mesons J /Ψ and ϒ on protons. Such cross-sections have been measured by both HERA experiments H1 and ZEUS in electron-proton collisions and by LHC experiments ALICE, CMS and LHCb in ultra-peripheral proton-proton and ultra-peripheral proton-lead collisions. Our approach provides a perturbative description of the rise with energy and relies only on a fit of the initial transverse momentum profile of the proton impact factor, which can be extracted from BFKL fits to inclusive HERA data. We find that BFKL evolution is capable to provide a very good description of the energy dependence of the current data set, while the available fits of the proton impact factor require an adjustment in the overall normalization.

  9. First measurement of coherent $\\phi$-meson photoproduction on deuteron at low energies

    SciTech Connect

    Tsutomu Mibe; Haiyan Gao; Kenneth Hicks; Kevin Kramer; Stepan Stepanyan; David Tedeschi; Moscov Amaryan; Pawel Ambrozewicz; Marco Anghinolfi; G. Asryan; Gerard Audit; Harutyun Avakian; Hovhannes Baghdasaryan; Nathan Baillie; Jacques Ball; Nathan Baltzell; Marco Battaglieri; Ivan Bedlinski; Ivan Bedlinskiy; Matthew Bellis; Nawal Benmouna; Barry Berman; Angela Biselli; Lukasz Blaszczyk; Sylvain Bouchigny; Sergey Boyarinov; Robert Bradford; Derek Branford; William Briscoe; William Brooks; Stephen Bueltmann; Volker Burkert; Cornel Butuceanu; John Calarco; Sharon Careccia; Daniel Carman; Shifeng Chen; Philip Cole; Patrick Collins; Philip Coltharp; Donald Crabb; Hall Crannell; Volker Crede; John Cummings; Natalya Dashyan; Rita De Masi; Raffaella De Vita; Enzo De Sanctis; Pavel Degtiarenko; Alexandre Deur; Kahanawita Dharmawardane; Richard Dickson; Chaden Djalali; Gail Dodge; Joseph Donnelly; David Doughty; Michael Dugger; Oleksandr Dzyubak; Hovanes Egiyan; Kim Egiyan; Lamiaa Elfassi; Latifa Elouadrhiri; Paul Eugenio; Gleb Fedotov; Gerald Feldman; Herbert Funsten; Michel Garcon; Gagik Gavalian; Gerard Gilfoyle; Kevin Giovanetti; Francois-Xavier Girod; John Goetz; Atilla Gonenc; Christopher Gordon; Ralf Gothe; Keith Griffioen; Michel Guidal; Nevzat Guler; Lei Guo; Vardan Gyurjyan; Cynthia Hadjidakis; Kawtar Hafidi; Hayk Hakobyan; Rafael Hakobyan; Charles Hanretty; John Hardie; F. Hersman; Ishaq Hleiqawi; Maurik Holtrop; Charles Hyde; Charles Hyde-Wright; Yordanka Ilieva; David Ireland; Boris Ishkhanov; Eugeny Isupov; Mark Ito; David Jenkins; Hyon-Suk Jo; John Johnstone; Kyungseon Joo; Henry Juengst; Narbe Kalantarians; James Kellie; Mahbubul Khandaker; Wooyoung Kim; Andreas Klein; Franz Klein; Alexei Klimenko; Mikhail Kossov; Zebulun Krahn; Laird Kramer; V. Kubarovsky; Joachim Kuhn; Sebastian Kuhn; Sergey Kuleshov; Viacheslav Kuznetsov; Jeff Lachniet; Jean Laget; Jorn Langheinrich; David Lawrence; Tsung-shung Lee; Ji Li; Kenneth Livingston; Haiyun Lu; Marion MacCormick; Claude Marchand; Nikolai Markov; Paul Mattione; Bryan McKinnon; Bernhard Mecking; Joseph Melone; Mac Mestayer; Curtis Meyer; Konstantin Mikhaylov; Ralph Minehart; Marco Mirazita; Rory Miskimen; Viktor Mokeev; Kei Moriya; Steven Morrow; M. Moteabbed; E. Munevar; Gordon Mutchler; P. Nadel-Turonski; Rakhsha Nasseripour; Silvia Niccolai; Gabriel Niculescu; Maria-Ioana Niculescu; Bogdan Niczyporuk; Megh Niroula; Rustam Niyazov; Mina Nozar; Mikhail Osipenko; Alexander Ostrovidov; K. Park; Evgueni Pasyuk; Craig Paterson; S. Anefalos Pereira; Joshua Pierce; Nikolay Pivnyuk; Dinko Pocanic; Oleg Pogorelko; S. Pozdniakov; John Price; Yelena Prok; Dan Protopopescu; Brian Raue; Gregory Riccardi; Giovanni Ricco; Marco Ripani; Barry Ritchie; Federico Ronchetti; Guenther Rosner; Patrizia Rossi; Franck Sabatie; Julian Salamanca; Carlos Salgado; Joseph Santoro; Vladimir Sapunenko; Reinhard Schumacher; Vladimir Serov; Youri Sharabian; Dmitri Sharov; Nikolay Shvedunov; Elton Smith; Lee Smith; Daniel Sober; Daria Sokhan; A. Stavinsky; Samuel Stepanyan; B.E. Stokes; Paul Stoler; I.I. Strakovsky; Steffen Strauch; Mauro Taiuti; Ulrike Thoma; Avtandil Tkabladze; Svyatoslav Tkachenko; Luminita Todor; Clarisse Tur; Maurizio Ungaro; Michael Vineyard; Alexander Vlassov; Daniel Watts; Lawrence Weinstein; Dennis Weygand; M. Williams; Elliott Wolin; Michael Wood; Amrit Yegneswaran; Lorenzo Zana; Jixie Zhang; Bo Zhao; Zhiwen Zhao

    2007-11-01

    The cross section and decay angular distributions for the coherent \\phi meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t =(p_{\\gamma}-p_{\\phi})^2 =-2 GeV^2/c^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a re-scattering model. In a framework of vector meson dominance, the data are consistent with the total \\phi-N cross section \\sigma_{\\phi N} at about 10 mb. If vector meson dominance is violated, a larger \\sigma_{\\phi N} is possible by introducing larger t-slope for the \\phi N \\to \\phi N process than that for the \\gamma N \\to \\phi N process. The decay angular distributions of the \\phi are consistent with helicity conservation.

  10. Study of the Hyperon-Nucleon Interaction in Exclusive Λ Photoproduction off the Deuteron

    SciTech Connect

    Zachariou, Nicholas; Ilieva, Yordanka; Cao, Tongtong

    2016-03-01

    The study of final-state interactions in exclusive hyperon photoproduction off the deuteron is a promising approach to extract information about the hyperon-nucleon (YN) interaction. First preliminary results on the azimuthal asymmetry ∑, as well as the polarization transfer coeffcients Ox, Oz, Cx, and Cz for the reaction γd → K+ Λn initiated with linearly and circularly polarized photon beam are presented. The data were taken with the CLAS detector in Hall B of Jefferson Lab during the E06-103 experiment. The large kinematic coverage of the CLAS, combined with the exceptionally high quality of the experimental data, allows identifying and selecting final-state interaction events to extract single- and double-polarization observables and their kinematical dependencies.

  11. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

    NASA Astrophysics Data System (ADS)

    Fanelli, C.; Cisbani, E.; Hamilton, D. J.; Salmé, G.; Wojtsekhowski, B.; Ahmidouch, A.; Annand, J. R. M.; Baghdasaryan, H.; Beaufait, J.; Bosted, P.; Brash, E. J.; Butuceanu, C.; Carter, P.; Christy, E.; Chudakov, E.; Danagoulian, S.; Day, D.; Degtyarenko, P.; Ent, R.; Fenker, H.; Fowler, M.; Frlez, E.; Gaskell, D.; Gilman, R.; Horn, T.; Huber, G. M.; de Jager, C. W.; Jensen, E.; Jones, M. K.; Kelleher, A.; Keppel, C.; Khandaker, M.; Kohl, M.; Kumbartzki, G.; Lassiter, S.; Li, Y.; Lindgren, R.; Lovelace, H.; Luo, W.; Mack, D.; Mamyan, V.; Margaziotis, D. J.; Markowitz, P.; Maxwell, J.; Mbianda, G.; Meekins, D.; Meziane, M.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Mulholland, J.; Nelyubin, V.; Pentchev, L.; Perdrisat, C. F.; Piasetzky, E.; Prok, Y.; Puckett, A. J. R.; Punjabi, V.; Shabestari, M.; Shahinyan, A.; Slifer, K.; Smith, G.; Solvignon, P.; Subedi, R.; Wesselmann, F. R.; Wood, S.; Ye, Z.; Zheng, X.

    2015-10-01

    Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θcmp=70 ° . The longitudinal transfer KLL, measured to be 0.645 ±0.059 ±0.048 , where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ˜3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

  12. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton.

    PubMed

    Fanelli, C; Cisbani, E; Hamilton, D J; Salmé, G; Wojtsekhowski, B; Ahmidouch, A; Annand, J R M; Baghdasaryan, H; Beaufait, J; Bosted, P; Brash, E J; Butuceanu, C; Carter, P; Christy, E; Chudakov, E; Danagoulian, S; Day, D; Degtyarenko, P; Ent, R; Fenker, H; Fowler, M; Frlez, E; Gaskell, D; Gilman, R; Horn, T; Huber, G M; de Jager, C W; Jensen, E; Jones, M K; Kelleher, A; Keppel, C; Khandaker, M; Kohl, M; Kumbartzki, G; Lassiter, S; Li, Y; Lindgren, R; Lovelace, H; Luo, W; Mack, D; Mamyan, V; Margaziotis, D J; Markowitz, P; Maxwell, J; Mbianda, G; Meekins, D; Meziane, M; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Mulholland, J; Nelyubin, V; Pentchev, L; Perdrisat, C F; Piasetzky, E; Prok, Y; Puckett, A J R; Punjabi, V; Shabestari, M; Shahinyan, A; Slifer, K; Smith, G; Solvignon, P; Subedi, R; Wesselmann, F R; Wood, S; Ye, Z; Zheng, X

    2015-10-09

    Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ_{cm}^{p}=70°. The longitudinal transfer K_{LL}, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

  13. Differential Photoproduction Cross Sections of the Sigma0(1385), Lambda(1405), and Lambda(1520)

    SciTech Connect

    Moriya, Kei; Schumacher, Reinhard A.

    2013-10-01

    We report the exclusive photoproduction cross sections for the Sigma(1385), Lambda(1405), and Lambda(1520) in the reactions gamma + p -> K+ + Y* using the CLAS detector for energies from near the respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential cross sections are integrated to give the total exclusive cross sections for each hyperon. Comparisons are made to current theoretical models based on the effective Lagrangian approach and fitted to previous data. The accuracy of these models is seen to vary widely. The cross sections for the Lambda(1405) region are strikingly different for the Sigma+pi-, Sigma0 pi0, and Sigma- pi+ decay channels, indicating the effect of isospin interference, especially at W values close to the threshold.

  14. Measurement of the transverse target and beam-target asymmetries in η meson photoproduction at MAMI.

    PubMed

    Akondi, C S; Annand, J R M; Arends, H J; Beck, R; Bernstein, A; Borisov, N; Braghieri, A; Briscoe, W J; Cherepnya, S; Collicott, C; Costanza, S; Downie, E J; Dieterle, M; Fix, A; Fil'kov, L V; Garni, S; Glazier, D I; Gradl, W; Gurevich, G; Hall Barrientos, P; Hamilton, D; Hornidge, D; Howdle, D; Huber, G M; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lazarev, A; Lisin, V; Livingston, K; MacGregor, I J D; Mancel, J; Manley, D M; Martel, P; McNicoll, E F; Meyer, W; Middleton, D; Miskimen, R; Mushkarenkov, A; Nefkens, B M K; Neganov, A; Nikolaev, A; Oberle, M; Ostrick, M; Ortega, H; Ott, P; Otte, P B; Oussena, B; Pedroni, P; Polonski, A; Polyanski, V V; Prakhov, S; Reicherz, G; Rostomyan, T; Sarty, A; Schumann, S; Steffen, O; Strakovsky, I I; Strub, Th; Supek, I; Tiator, L; Thomas, A; Unverzagt, M; Usov, Yu A; Watts, D P; Werthmüller, D; Witthauer, L; Wolfes, M

    2014-09-05

    We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the γ[over →]p[over →]→ηp reaction up to a center-of-mass energy of W=1.9  GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of η meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed.

  15. Exclusive η photoproduction and Σ beam asymmetries at GlueX

    NASA Astrophysics Data System (ADS)

    McGinley, William; GlueX Collaboration Collaboration

    2017-01-01

    The goal of the GlueX experiment is to study the gluonic degrees of freedom in QCD by mapping the light meson spectrum with an emphasis on hybrid exotic states. This will be done using a tagged, linearly-polarized 9 GeV photon beam incident on a hydrogen target. Early measurements of exclusive η photoproduction will provide insight into the reaction mechanism. The GlueX experiment is making the first Σ beam asymmetry measurement for the η in this energy range and is expected to further constrain Regge theory models for photoproduced pseudoscalar mesons. This talk will present preliminary results for the photon beam Σ asymmetry for multiple decay modes of the exclusive reaction γ p -> η p using data from a recent commissioning run. Supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-FG02-87ER40315.

  16. Polarization transfer in wide-angle Compton scattering and single-pion photoproduction from the proton

    SciTech Connect

    Fanelli, Cristiano V.

    2015-10-06

    Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θPcm = 70°. The longitudinal transfer KLL, measured to be 0.645 ± 0.059 ± 0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

  17. Polarization transfer in wide-angle Compton scattering and single-pion photoproduction from the proton

    DOE PAGES

    Fanelli, Cristiano V.

    2015-10-06

    Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θPcm = 70°. The longitudinal transfer KLL, measured to be 0.645 ± 0.059 ± 0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton.more » However, the observed value is ~3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.« less

  18. Ultrafast Barrierless Photoisomerization and Strong Ultraviolet Absorption of Photoproducts in Plant Sunscreens.

    PubMed

    Luo, Jian; Liu, Yan; Yang, Songqiu; Flourat, Amandine L; Allais, Florent; Han, Keli

    2017-03-02

    Sunscreens are aimed at protecting skin from solar ultraviolet (UV) irradiation. By utilizing femtosecond transient absorption spectroscopy and time-dependent density functional theory, we explain nature's selection of sinapoyl malate rather than sinapic acid as the plant sunscreen molecule. In physiological pH conditions, the two molecules are deprotonated, and their excited ππ* states are found to relax to the ground states in a few tens of picoseconds via a barrierless trans-cis photoisomerization. After the cis-photoproduct is formed, the efficacy of sinapic acid is greatly reduced. In contrast, the efficacy of sinapoyl malate is affected only slightly because the cis-product still absorbs UV light strongly. In addition, protonated sinapic acid is found to be a good potential sunscreen molecule.

  19. Photo-production of ω Meson Using CLAS at Jefferson Laboratory

    NASA Astrophysics Data System (ADS)

    Akbar, Zulkaida

    2017-01-01

    Photo-production of ω meson was studied using CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. We have obtained preliminary results on two observables that have been measured from the reaction γp -> p ω : the differential cross section and the double polarization observable E. The differential cross section measurement was performed using tagged photon beam with energy range up to 5.4 GeV, incident on unpolarized liquid hydrogen target. While the double polarization observable E was measured using circularly-polarized tagged photon beam with energy range up to 2.4 GeV and longitudinally-polarized butanol target. The differential cross section as well as the polarization observable allow us to find the N* resonances that decay to p ω through multi-channel Partial Wave Analysis (PWA) method. They also provide a probe to test theoretical models about the production mechanism of ω meson and also the scaling behavior of the cross section.

  20. First measurement of the helicity asymmetry E in η photoproduction on the proton

    SciTech Connect

    Senderovich, I.; Morrison, B. T.; Dugger, M.; Ritchie, B. G.; Pasyuk, E.; Tucker, R.; Brock, J.; Carlin, C.; Keith, C. D.; Meekins, D. G.; Seely, M. L.; Rönchen, D.; Döring, M.; Collins, P.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Anderson, M. D.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Credé, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Klein, F. J.; Kubarovsky, V.; Kunkel, M. C.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Park, K.; Park, S.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.

    2016-01-26

    Results are presented for the first measurement of the double-polarization helicity asymmetry E for the η photoproduction reaction γ p → ηp. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the Jülich–Bonn model to examine the case for the existence of a narrow N* resonance between 1.66 and 1.70 GeV. The addition of these data to the world database results in marked changes in the predictions for the E observable from that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances.

  1. DIFFERENTIAL CROSS SECTION ANALYSIS IN KAON PHOTOPRODUCTION USING ASSOCIATED LEGENDRE POLYNOMIALS

    SciTech Connect

    P. T. P. HUTAURUK, D. G. IRELAND, G. ROSNER

    2009-04-01

    Angular distributions of differential cross sections from the latest CLAS data sets,6 for the reaction γ + p→K+ + Λ have been analyzed using associated Legendre polynomials. This analysis is based upon theoretical calculations in Ref. 1 where all sixteen observables in kaon photoproduction can be classified into four Legendre classes. Each observable can be described by an expansion of associated Legendre polynomial functions. One of the questions to be addressed is how many associated Legendre polynomials are required to describe the data. In this preliminary analysis, we used data models with different numbers of associated Legendre polynomials. We then compared these models by calculating posterior probabilities of the models. We found that the CLAS data set needs no more than four associated Legendre polynomials to describe the differential cross section data. In addition, we also show the extracted coefficients of the best model.

  2. Behavior of a fenhexamid photoproduct during the alcoholic fermentation of Saccharomyces cerevisiae.

    PubMed

    Cabras, Paolo; Farris, Giovanni A; Pinna, Maria V; Pusino, Alba

    2004-12-29

    The fungicide fenhexamid [N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide] degraded rapidly by UV or sunlight irradiation, yielding 7-chloro-6-hydroxy-2-(1-methylcyclohexyl)-1,3-benzoxazole (CHB) as a main photoproduct. CHB was isolated, and its effect on alcoholic fermentation of Saccharomyces cerevisiae was studied. The results indicate that the presence of CHB does not affect the extent of alcohol production. After 12 days, the amount of CHB in the fermentation medium decreased by ca. 65%. Only 25% of the missing CHB was recovered unchanged from yeasts, most likely because it was adsorbed on the yeast wall cell. The remaining part degraded during the fermentation process. Glucan and chitin, two potential adsorbents, which constitute yeast cell walls, exhibited affinity for CHB.

  3. Isobar model analysis of {pi}{sup 0{eta}} photoproduction on protons

    SciTech Connect

    Fix, A.; Lee, A.; Kashevarov, V. L.; Ostrick, M.

    2010-09-15

    Photoproduction of {pi}{sup 0{eta}} on protons in the energy range from threshold to 1.4 GeV is discussed. The data for representative angular distributions recently obtained at MAMI C are analyzed using an isobar model. The isobars considered are {Delta}(1232) and S{sub 11}(1535) for {pi}{sup 0}p and {eta}p states, respectively. In accordance with the results of earlier works, the main features of the reaction are explained through the dominance of the D{sub 33} wave with a relatively small admixture of positive parity resonances. Comparison with recent experimental results for the photon beam asymmetry is carried out.

  4. φ-meson Photoproduction By Using a Beam of Linearly-Polarized

    NASA Astrophysics Data System (ADS)

    Salamanca, Julian; Cole, Philip

    2007-10-01

    The observables afforded by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. And in particular, I shall describe how phi meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal will be measure the γ p ->φp reaction, with φ->K^+K^-, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory (Newport News, VA). The data were collected during the g8b run in the summer of 2005.

  5. φ-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies

    NASA Astrophysics Data System (ADS)

    Salamanca, Julian; Cole, Philip L.

    2007-10-01

    The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how φ-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the γ⃗p→φp reaction, with φ→K+K-, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.

  6. Exclusive photoproduction of J/ψ and ψ(2S) in pp and AA collisions

    SciTech Connect

    Cisek, Anna; Schäfer, Wolfgang; Szczurek, Antoni

    2015-04-10

    The amplitude for γp → J/ψp(γp → ψ'p) is calculated in a pQCD k{sub ⊥}-factorization approach. The total cross section for this process is calculated for different unintegrated gluon distributions and compared with the HERA data and the data extracted recently by the LHCb collaboration. The amplitude for γp → J/ψp(γp → ψ'p) is used to predict the cross section for exclusive photoproduction of the J/ψ(ψ') meson in proton-proton and nucleus-nucleus collisions. In the pp case, compared to earlier calculations we include both Dirac and Pauli electromagnetic form factors. We also discuss the dependence of nuclear shadowing on the charmonium state.

  7. Penrose photoproduction processes - A high efficiency energy mechanism for active galactic nuclei and quasars

    NASA Technical Reports Server (NTRS)

    Leiter, D.; Kafatos, M.

    1979-01-01

    Recent observations of NGC 4151 and 3C273 suggest that the nuclei of active galaxies have very high gamma ray efficiencies. In addition, optical studies of M87 have indicated the possibility of a massive black hole in its central region. The above facts have led to study of a new physical mechanism, Penrose Photoproduction Processes, in the ergospheres of massive Kerr black holes, as a way to account for the fluctuating, high efficiency, energy production associated with active galaxies and quasars. Observational signatures, associated with this mechanism, occur in the form of approximately 2 MeV and approximately 2 GeV gamma ray cutoffs which might be corroborated by the observed spectra of NGC 4151 and 3C273, respectively.

  8. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Barakbaev, A. N.; Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Bokhonov, V.; Boos, E. G.; Borras, K.; Brock, I.; Brugnera, R.; Bruni, A.; Brzozowska, B.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; D'Agostini, G.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Drugakov, V.; Dusini, S.; Ferrando, J.; Figiel, J.; Foster, B.; Gach, G.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Gogota, O.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hartner, G.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Kadenko, I.; Kananov, S.; Kanno, T.; Karshon, U.; Kaur, M.; Kaur, P.; Khein, L. A.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Makarenko, I.; Malka, J.; Martin, J. F.; Mergelmeyer, S.; Mohamad Idris, F.; Mujkic, K.; Myronenko, V.; Nagano, K.; Nigro, A.; Nobe, T.; Notz, D.; Nowak, R. J.; Olkiewicz, K.; Onishchuk, Yu.; Paul, E.; Perlański, W.; Perrey, H.; Pokrovskiy, N. S.; Proskuryakov, A. S.; Przybycień, M.; Raval, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Samojlov, V.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Schwartz, J.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Sola, V.; Solano, A.; Spiridonov, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Temiraliev, T.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Wan Abdullah, W. A. T.; Wichmann, K.; Wing, M.; Wolf, G.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

    2014-03-01

    The photoproduction of isolated photons, both inclusive and together with a jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of 374 pb. Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6

  9. Measurement of the t dependence in exclusive photoproduction of ϒ(1S) mesons at HERA

    NASA Astrophysics Data System (ADS)

    ZEUS Collaboration; Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bołd, T.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bołd, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.-P.; Januschek, F.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotański, A.; Kötz, U.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlański, W.; Perrey, H.; Piotrzkowski, K.; Pluciński, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycień, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Słomiński, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zhou, C.; Zichichi, A.; Zolkapli, Z.; Zolko, M.; Zotkin, D. S.

    2012-02-01

    The exclusive photoproduction reaction γp→ϒ(1S)p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb. The measurement covers the kinematic range 60

  10. Further studies of the photoproduction of isolated photons with a jet at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Barakbaev, A. N.; Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Bokhonov, V.; Boos, E. G.; Borras, K.; Brock, I.; Brugnera, R.; Bruni, A.; Brzozowska, B.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; D'Agostini, G.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Drugakov, V.; Dusini, S.; Ferrando, J.; Figiel, J.; Foster, B.; Gach, G.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Gogota, O.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hartner, G.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Kadenko, I.; Kananov, S.; Kanno, T.; Karshon, U.; Kaur, M.; Kaur, P.; Khein, L. A.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Makarenko, I.; Malka, J.; Martin, J. F.; Mergelmeyer, S.; Idris, F. Mohamad; Mujkic, K.; Myronenko, V.; Nagano, K.; Nigro, A.; Nobe, T.; Notz, D.; Nowak, R. J.; Olkiewicz, K.; Onishchuk, Yu.; Paul, E.; Perlanski, W.; Perrey, H.; Pokrovskiy, N. S.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Samojlov, V.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Schwartz, J.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Sola, V.; Solano, A.; Spiridonov, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Temiraliev, T.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Abdullah, W. A. T. Wan; Wichmann, K.; Wing, M.; Wolf, G.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

    2014-08-01

    In this extended analysis using the ZEUS detector at HERA, the photoproduction of isolated photons together with a jet is measured for different ranges of the fractional photon energy, x {/γ meas}, contributing to the photon-jet final state. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 6 < E {/T γ } < 15 GeV and -0 .7 < η γ < 0 .9, and for jet transverse-energy and pseudorapidity ranges 4 < E {/T jet} < 35 GeV and -1 .5 < η jet < 1 .8, for an integrated luminosity of 374 pb-1. The kinematic observables studied comprise the transverse energy and pseudorapidity of the photon and the jet, the azimuthal difference between them, the fraction of proton energy taking part in the interaction, and the difference between the pseudorapidities of the photon and the jet. Higher-order theoretical calculations are compared to the results.

  11. Ultraviolet irradiation of DNA complexed with. alpha. /. beta. -type small, acid-soluble proteins from spores of Bacillus or Clostridium species makes spore photoproduct but not thymine dimers

    SciTech Connect

    Nicholson, W.L.; Setlow, B.; Setlow, P. )

    1991-10-01

    UV irradiation of complexes of DNA and an {alpha}/{beta}-type small, acid-soluble protein (SASP) from Bacillus subtilis spores gave decreasing amounts of pyrimidine dimers and increasing amounts of spore photoproduct as the SASP/DNA ratio was increased. The yields of pyrimidine dimers and spore photoproduct were < 0.2% and 8% of total thymine, respectively, when DNA saturated with SASP was irradiated at 254 nm with 30 kJ/m{sup 2}; in the absence of SASP the yields were reversed - 4.5% and 0.3%, respectively. Complexes of DNA with {alpha}/{beta}-type SASP from Bacillus cereus, Bacillus megaterium, or Clostridium bifermentans spores also gave spore photoproduct upon UV irradiation. However, incubation of these SASPs with DNA under conditions preventing complex formation or use of mutant SASPs that do not form complexes did not affect the photoproducts formed in vitro. These results suggest that the UV photochemistry of bacterial spore DNA in vivo is due to the binding of {alpha}/{beta}-type SASP, a binding that is known to cause a change in DNA conformation in vitro from the B form to the A form. The yields of spore photoproduct in vitro were significantly lower than in vivo, perhaps because of the presence of substances other than SASP in spores. It is suggested that as these factors diffuse out in the first minutes of spore germination, spore photoproduct yields become similar to those observed for irradiation of SASP/DNA complexes in vitro.

  12. Photoproduction of Scalar Mesons Using the CEBAF Large Acceptance Spectrometer (CLAS)

    NASA Astrophysics Data System (ADS)

    Chandavar, Shloka K.

    The search for glueballs has been ongoing for several decades. The lightest glueball has been predicted by quenched lattice QCD to have mass in the range of 1.0--1.7 GeV and JPC = 0++ . The mixing of glueball states with neighbouring meson states complicates their identification and hence several experiments have been carried out over the years to study the glueball candidates. By analyzing the decay channels and production mechanisms of these candidates, their glueball content can theoretically be determined. In reality, a lot of confusion still exists about the status of these glueball candidates. The f0(1500) is one of several contenders for the lightest glueball, which has been extensively studied in several different kinds of experiments. However, there exists no photoproduction data on this particle. In the analysis presented in this dissertation, the presence of the f0(1500) in the KS 0KS0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility, also called Jefferson Lab (JLab). This is done by studying the reaction, gammap → fJp → KS0 KS0p → 2(pi +pi-)p using data from the g12 experiment. A clear peak is seen at 1500 MeV in the background subtracted data. This is enhanced if the momentum transfer is restricted to be less than 1 GeV2. Comparing with simulations, it is seen that this peak is associated with t channel production mechanism. The f 2'(1525) has a mass of 1525 MeV and a width of 73 MeV, and hence there is a possibility of it contributing to the peak observed in our data. A moments analysis seems to suggest some presence of a D wave, however, the low acceptance at forward and backward angles prohibits a definitive conclusion.

  13. Exclusive ρ0 meson photoproduction with a leading neutron at HERA

    NASA Astrophysics Data System (ADS)

    Goerlich, Lidia

    2016-11-01

    A first measurement is presented of exclusive photoproduction of ρ0 mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of √s = 319 GeV and correspond to an integrated luminosity of 1.16pb-1. The ρ0 mesons with transverse momenta pT < 1 GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, xL > 0.35, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality Q2 < 2 GeV2, the total energy of the photon-proton system 20 < Wγp < 100 GeV and the polar angle of the leading neutron θn < 0.75 mrad. The cross section of the reaction γp → ρ0nπ+ is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ρ0 meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, σel(γπ+ → ρ°π+), is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction γp → ρ°nπ+.

  14. Exclusive ρ ^0 meson photoproduction with a leading neutron at HERA

    NASA Astrophysics Data System (ADS)

    Andreev, V.; Baghdasaryan, A.; Begzsuren, K.; Belousov, A.; Bolz, A.; Boudry, V.; Brandt, G.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Cerny, K.; Chekelian, V.; Contreras, J. G.; Cvach, J.; Dainton, J. B.; Daum, K.; Diaconu, C.; Dobre, M.; Dodonov, V.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Haidt, D.; Henderson, R. C. W.; Hladkỳ, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kretzschmar, J.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Malinovski, E.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meyer, A. B.; Meyer, H.; Meyer, J.; Mikocki, S.; Morozov, A.; Müller, K.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nowak, G.; Olsson, J. E.; Ozerov, D.; Pascaud, C.; Patel, G. D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Plačakytė, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rusakov, S.; Šálek, D.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schöning, A.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Straumann, U.; Sykora, T.; Thompson, P. D.; Traynor, D.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wünsch, E.; Žáček, J.; Zhang, Z.; Žlebčík, R.; Zohrabyan, H.; Zomer, F.

    2016-01-01

    A first measurement is presented of exclusive photoproduction of ρ ^0 mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of √{s}=319 GeV and correspond to an integrated luminosity of 1.16 pb^{-1}. The ρ ^0 mesons with transverse momenta p_T<1 GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, x_L>0.35, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality Q^2 < 2 GeV^2, the total energy of the photon-proton system 20 < W_{γ p}< 100 GeV and the polar angle of the leading neutron θ _n < 0.75 mrad. The cross section of the reaction γ p → ρ ^0 n π ^+ is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ρ ^0 meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, σ ^el(γ π ^+ → ρ ^0π ^+), is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction γ p → ρ ^0 n π ^+.

  15. The Enzyme-Mediated Direct Reversal of a Dithymine Photoproduct in Germinating Endospores

    PubMed Central

    Yang, Linlin; Li, Lei

    2013-01-01

    Spore photoproduct lyase (SPL) repairs a special thymine dimer, 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct, or SP, in germinating endospores. SP is the exclusive DNA photo-damaging product found in endospores; its generation and swift repair by SPL are responsible for the spores’ extremely high UV resistance. Early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair SP in the absence of light. Recently, it has been established that SPL belongs to the radical S-adenosylmethionine (SAM) superfamily. The enzymes in this superfamily utilize a tri-cysteine CXXXCXXC motif to bind a [4Fe-4S] cluster. The cluster provides an electron to the S-adenosylmethionine (SAM) to reductively cleave its C5′-S bond, generating a reactive 5′-deoxyadenosyl (5′-dA) radical. This 5′-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. The H atom donor is suggested to be a conserved cysteine141 in B. subtilis SPL; the resulting thiyl radical likely interacts with a neighboring tyrosine99 before oxidizing the 5′-dA to 5′-dA radical and, subsequently, regenerating SAM. These findings suggest SPL to be the first enzyme in the large radical SAM superfamily (>44,000 members) to utilize a radical transfer pathway for catalysis; its study should shed light on the mechanistic understanding of the SAM regeneration process in other members of the superfamily. PMID:23799365

  16. Exclusive vector meson photoproduction at the LHC and a future circular collider: A closer look on the final state

    NASA Astrophysics Data System (ADS)

    da Silveira, G. Gil; Gonçalves, V. P.; Jaime, M. M.

    2017-02-01

    Over the past years, the LHC experiments have reported experimental evidence for processes associated to photon-photon and photon-hadron interactions, showing their potential to investigate the production of low- and high-mass systems in exclusive events. In the particular case of the photoproduction of vector mesons, the experimental study of this final state is expected to shed light on the description of the QCD dynamics at small values of the Bjorken-x variable. In this paper, we extend previous studies for the exclusive J /Ψ and ϒ photoproduction in p p collisions based on the nonlinear QCD dynamics by performing a detailed study of the final-state distributions that can be measured experimentally at the LHC and at a future circular collider. Predictions for the rapidity and transverse momentum distributions of the vector mesons and of final-state dimuons are presented for p p collisions at √{s }=7 , 13, and 100 TeV.

  17. Energy dependence of dissociative J/ψ photoproduction as a signature of gluon saturation at the LHC

    NASA Astrophysics Data System (ADS)

    Cepila, J.; Contreras, J. G.; Tapia Takaki, J. D.

    2017-03-01

    We have developed a model in which the quantum fluctuations of the proton structure are characterised by hot spots, whose number grows with decreasing Bjorken-x. Our model reproduces the F2 (x ,Q2) data from HERA at the relevant scale, as well as the exclusive and dissociative J / ψ photoproduction data from H1 and ALICE. Our model predicts that for Wγp ≈ 500 GeV, the dissociative J / ψ cross section reaches a maximum and then decreases steeply with energy, which is in qualitatively good agreement to a recent observation that the dissociative J / ψ background in the exclusive J / ψ sample measured in photoproduction by ALICE decreases as energy increases. Our prediction provides a clear signature for gluon saturation at LHC energies.

  18. Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach

    SciTech Connect

    Biplab Dey, Michael E. McCracken, David G. Ireland, Curtis A. Meyer

    2011-05-01

    The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known CGLN formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.

  19. Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach

    SciTech Connect

    Dey, Biplab; Meyer, Curtis A.; McCracken, Michael E.; Ireland, David G.

    2011-05-15

    The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known Chew-Goldberger-Low-Nambu formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.

  20. Upper limits for the photoproduction cross section for the Φ⁻⁻(1860) pentaquark state off the deuteron

    SciTech Connect

    Egiyan, H.; Langheinrich, J.; Gothe, R. W.; Graham, L.; Holtrop, M.; Lu, H.; Mattione, P.; Mutchler, G.; Park, K.; Smith, E. S.; Stepanyan, S.; Zhao, Z. W.; Adhikari, K. P.; Aghasyan, M.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bookwalter, C.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Contalbrigo, M.; D’Angelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Dey, B.; Dickson, R.; Djalali, C.; Doughty, D.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Heddle, D.; Hicks, K.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jo, H. S.; Joo, K.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Livingston, K.; MacGregor, I. J. D.; Mao, Y.; Mayer, M.; McKinnon, B.; Mokeev, V.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niculescu, G.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, S.; Pasyuk, E.; Anefalos Pereira, S.; Phelps, E.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Stepanyan, S. S.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tedeschi, D. J.; Ungaro, M.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhao, B.

    2012-01-30

    We searched for the Φ⁻⁻(1860) pentaquark in the photoproduction process off the deuteron in the Ξ⁻π⁻-decay channel using CLAS. The invariant-mass spectrum of the Ξ⁻π⁻ system does not indicate any statistically significant enhancement near the reported mass M=1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90%-confidence-level upper limit of 0.7 nb for the photoproduction cross section of Φ⁻⁻(1860) with a consecutive decay intoΞ⁻π⁻ in the photon-energy range 4.5GeVγ<5.5GeV.

  1. Upper limits for the photoproduction cross section for the Φ⁻⁻(1860) pentaquark state off the deuteron

    DOE PAGES

    Egiyan, H.; Langheinrich, J.; Gothe, R. W.; ...

    2012-01-30

    We searched for the Φ⁻⁻(1860) pentaquark in the photoproduction process off the deuteron in the Ξ⁻π⁻-decay channel using CLAS. The invariant-mass spectrum of the Ξ⁻π⁻ system does not indicate any statistically significant enhancement near the reported mass M=1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90%-confidence-level upper limit of 0.7 nb for the photoproduction cross section of Φ⁻⁻(1860) with a consecutive decay intoΞ⁻π⁻ in the photon-energy range 4.5GeVγ<5.5GeV.

  2. The growth with energy of exclusive J/Ψ and ϒ photo-production cross-sections and BFKL evolution

    NASA Astrophysics Data System (ADS)

    Hentschinski, Martin

    2017-03-01

    We investigate whether NLO BFKL evolution is capable to describe the energy dependence of the exclusive photo-production cross-section of vector mesons J/Ψ and ϒ on protons. Our description is based on available NLO BFKL fits of the proton impact factor in inclusive DIS, which allow us to construct the necessary scattering amplitude at zero momentum transfer t = 0. Assuming an exponential drop-off with t, this result allows us to calculate the exclusive photoproduction cross-section. Comparing our results with both HERA data (measured by H1 and ZEUS collaborations in ep collision) and LHC data (measured by ALICE, CMS and LHCb collaborations in ultra-peripheral pp and pPb collision) we find that our framework provides a very good description of the energy dependence of the J/Ψ and ϒ photoproduction cross-section, providing therefore further evidence for BFKL evolution at the LHC. The available fits of the proton impact factor require on the other hand an adjustment in the overall normalization.

  3. Diagnostic value of the recombinant tandem repeat antigen TeGM6-4r for surra in water buffaloes.

    PubMed

    Nguyen, Thu-Thuy; Zhou, Mo; Ruttayaporn, Ngasaman; Nguyen, Quoc Doanh; Nguyen, Viet Khong; Goto, Yasuyuki; Suzuki, Yasuhiko; Kawazu, Shin-ichiro; Inoue, Noboru

    2014-03-17

    Trypanosoma evansi infection, or surra, is currently affecting various species of animals, especially water buffaloes. Since diagnosis is an important aspect of surra control, development of novel diagnostic antigens is of interest to implement and improve the currently utilized methods. Our study evaluated the tandem repeat antigen TeGM6-4r in T. evansi antibody detection in water buffaloes. TeGM6-4r-based ELISA was performed with 20 positive and 8 negative controls and 484 field samples from water buffaloes in Northern Vietnam. To examine cross-reactivity, sera from Japanese cattle that had been experimentally infected with Theileria orientalis (n=10), Babesia bovis (n=3), Babesia bigemina (n=7) and Trypanosoma theileri (n=59) were included in the study. The sensitivity of the test was 80%. TeGM6-4r did not react with Theileria or Babesia infected sera, however it showed cross reactivity with 11/59 T. theileri infected samples. The reference test, CATT/T. evansi also reacted with 3/59 T. theileri infected sera. The lysate antigen-based ELISA reacted with 4/59 T. theileri, 9/10 Theileria and 3/10 Babesia infected sera. In contrast, TeGM6-4r-based ELISA was 86.3% sensitive and 58.3% specific in the screening of field samples. The average seroprevalence of T. evansi infection among water buffaloes in Northern Vietnam was 27.1% by CATT/T. evansi and 53.7% by TeGM6-4r. Seroprevalence in the five surveyed provinces ranged from 17.4% to 39.8% in the reference test, and 47.3% to 67.3% in the recombinant antigen based test. The finding indicated that the disease is still widely endemic in the area and that surveillance programs need to be carried out regularly to better control surra. We proposed TeGM6-4r as a useful serodiagnostic antigen for the detection and epidemiological surveillance of T. evansi infection among water buffaloes.

  4. 41 CFR 304-6.4 - What form must we use to report payments received by the agency from non-Federal sources?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... report payments received by the agency from non-Federal sources? 304-6.4 Section 304-6.4 Public Contracts and Property Management Federal Travel Regulation System PAYMENT OF TRAVEL EXPENSES FROM A NON-FEDERAL SOURCE AGENCY REQUIREMENTS 6-PAYMENT GUIDELINES Reports § 304-6.4 What form must we use to...

  5. 41 CFR 304-6.4 - What form must we use to report payments received by the agency from non-Federal sources?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... report payments received by the agency from non-Federal sources? 304-6.4 Section 304-6.4 Public Contracts and Property Management Federal Travel Regulation System PAYMENT OF TRAVEL EXPENSES FROM A NON-FEDERAL SOURCE AGENCY REQUIREMENTS 6-PAYMENT GUIDELINES Reports § 304-6.4 What form must we use to...

  6. 41 CFR 304-6.4 - What form must we use to report payments received by the agency from non-Federal sources?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... report payments received by the agency from non-Federal sources? 304-6.4 Section 304-6.4 Public Contracts and Property Management Federal Travel Regulation System PAYMENT OF TRAVEL EXPENSES FROM A NON-FEDERAL SOURCE AGENCY REQUIREMENTS 6-PAYMENT GUIDELINES Reports § 304-6.4 What form must we use to...

  7. 41 CFR 304-6.4 - What form must we use to report payments received by the agency from non-Federal sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... report payments received by the agency from non-Federal sources? 304-6.4 Section 304-6.4 Public Contracts and Property Management Federal Travel Regulation System PAYMENT OF TRAVEL EXPENSES FROM A NON-FEDERAL SOURCE AGENCY REQUIREMENTS 6-PAYMENT GUIDELINES Reports § 304-6.4 What form must we use to...

  8. 41 CFR 304-6.4 - What form must we use to report payments received by the agency from non-Federal sources?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... report payments received by the agency from non-Federal sources? 304-6.4 Section 304-6.4 Public Contracts and Property Management Federal Travel Regulation System PAYMENT OF TRAVEL EXPENSES FROM A NON-FEDERAL SOURCE AGENCY REQUIREMENTS 6-PAYMENT GUIDELINES Reports § 304-6.4 What form must we use to...

  9. Mechanistic studies of the radical SAM enzyme spore photoproduct lyase (SPL).

    PubMed

    Li, Lei

    2012-11-01

    Spore photoproduct lyase (SPL) repairs a special thymine dimer 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct or SP at the bacterial early germination phase. SP is the exclusive DNA photo-damage product in bacterial endospores; its generation and swift repair by SPL are responsible for the spores' extremely high UV resistance. The early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair the SP in the absence of light. The research in the past decade further established SPL as a radical SAM enzyme, which utilizes a tri-cysteine CXXXCXXC motif to harbor a [4Fe-4S] cluster. At the 1+ oxidation state, the cluster provides an electron to the S-adenosylmethionine (SAM), which binds to the cluster in a bidentate manner as the fourth and fifth ligands, to reductively cleave the CS bond associated with the sulfonium ion in SAM, generating a reactive 5'-deoxyadenosyl (5'-dA) radical. This 5'-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. SAM is suggested to be regenerated at the end of each catalytic cycle; and only a catalytic amount of SAM is needed in the SPL reaction. The H atom source for the back donation step is suggested to be a cysteine residue (C141 in Bacillus subtilis SPL), and the H-atom transfer reaction leaves a thiyl radical behind on the protein. This thiyl radical thus must participate in the SAM regeneration process; however how the thiyl radical abstracts an H atom from the 5'-dA to regenerate SAM is unknown. This paper reviews and discusses the history and the latest progress in the mechanistic elucidation of SPL. Despite some recent breakthroughs, more questions are raised in the mechanistic understanding of this intriguing DNA repair enzyme. This article is part of a Special Issue

  10. Mechanism elucidation of the radical SAM enzyme spore photoproduct lyase (SPL)

    PubMed Central

    Li, Lei

    2011-01-01

    Spore photoproduct lyase (SPL) repairs a special thymine dimer 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct or SP at the bacterial early germination phase. SP is the exclusive DNA photo-damage product in bacterial endospores; its generation and swift repair by SPL are responsible for the spores’ extremely high UV resistance. The early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair the SP in the absence of light. The research in the past decade further established SPL as a radical SAM enzyme, which utilizes a tri-cysteine CXXXCXXC motif to harbor a [4Fe-4S] cluster. At the 1+ oxidation state, the cluster provides an electron to the S-adenosylmethionine (SAM), which binds to the cluster in a bidentate manner as the fourth and fifth ligands, to reductively cleave the C-S bond associated with the sulfonium ion in SAM, generating a reactive 5′-deoxyadenosyl (5′-dA) radical. This 5′-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. SAM is suggested to be regenerated at the end of each catalytic cycle; and only a catalytic amount of SAM is needed in the SPL reaction. The H atom source for the back donation step is suggested to be a cysteine residue (C141 in B. subtilis SPL), and the H-atom transfer reaction leaves a thiyl radical behind on the protein. This thiyl radical thus must participate in the SAM regeneration process; however how the thiyl radical abstracts an H atom from the 5′-dA to regenerate SAM is unknown. This paper reviews and discusses the history and the latest progress in the mechanistic elucidation of SPL. Despite some recent breakthroughs, more questions are raised in the mechanistic understanding of this intriguing DNA repair enzyme. PMID:22197590

  11. Mechanistic Studies of the Spore Photoproduct Lyase (SPL) via a Single Cysteine Mutation

    PubMed Central

    Yang, Linlin; Lin, Gengjie; Nelson, Renae S.; Jian, Yajun; Telser, Joshua; Li, Lei

    2012-01-01

    5-thyminyl-5,6-dihydrothymine (also called spore photoproduct or SP) is the exclusive DNA photo-damage product in bacterial endospores. It is repaired by a radical SAM (S-adenosylmethionine) enzyme, the spore photoproduct lyase (SPL), at the bacterial early germination phase. Our previous studies proved that SPL utilizes the 5′-dA• generated by SAM cleavage reaction to abstract the H6proR atom to initiate the SP repair process. The resulting thymine allylic radical was suggested to take an H atom from an unknown protein source, most likely the cysteine 141. Here we show that C141 can be readily alkylated in the native SPL by iodoacetamide treatment, suggesting that it is accessible to the TpT radical. SP repair by the SPL C141A mutant yields TpTSO2− and TpT simultaneously from the very beginning of the reaction; no lag phase is observed for the TpTSO2− formation. Should any other protein residue serve as the H donor, its presence would result in TpT as the major product at least for the first enzyme turnover. These observations provide strong evidence to support C141 as the direct H atom donor. Moreover, due to the lack of this intrinsic H donor, the C141A mutant produces TpT via an unprecedented thymine cation radical reduction (proton coupled electron transfer) process, contrasting to the H atom transfer mechanism in the WT SPL reaction. The C141A mutant repairs SP at a rate which is ~3-fold slower than the WT enzyme. Formation of TpTSO2− and TpT exhibit a Vmax deuterium kinetic isotope effect (KIE) of 1.7 ± 0.2 respectively, which is smaller than the DVmax KIE of 2.8 ± 0.3 determined in the WT SPL reaction. These findings suggest that removing the intrinsic H atom donor disturbs the rate-limiting process in the enzyme catalysis. As expected, the pre-reduced C141A mutant only supports ~ 0.4 turnover, which is in sharp contrast to the > 5 turnovers exhibited by the WT SPL reaction, suggesting that the enzyme catalytic cycle (SAM regeneration) is

  12. Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure

    PubMed Central

    Premi, Sanjay; Wallisch, Silvia; Mano, Camila M.; Weiner, Adam B.; Bacchiocchi, Antonella; Wakamatsu, Kazumasa; Bechara, Etelvino J. H.; Halaban, Ruth; Douki, Thierry; Brash, Douglas E.

    2015-01-01

    Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPD), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. Here we show that in melanocytes, CPD are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These “dark CPD” constitute the majority of CPD and include the cytosine-containing CPD that initiate UV-signature C→T mutations. Dark CPD arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but that induces CPD by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically-generated excited electronic states are relevant to mammalian biology. PMID:25700512

  13. Photoproduction of η -mesons off nuclei for Eγ ⩽ 2.2 GeV

    NASA Astrophysics Data System (ADS)

    Mertens, T.; Jaegle, I.; Mühlich, P.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fornet-Ponse, K.; Fuchs, M.; Funke, C.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Lang, M.; Langheinrich, J.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Messchendorp, J. G.; Metag, V.; Morales, C.; Mosel, U.; Nanova, M.; Novinski, D. V.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Radkov, A. K.; Roy, A.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, C.; Wendel, C.

    2008-11-01

    The photoproduction of η -mesons off 12C , 40Ca , 93Nb , and nat Pb nuclei has been measured with a tagged photon beam with energies between 0.6 and 2.2GeV. The experiment was performed at the Bonn ELSA accelerator with the combined setup of the Crystal Barrel and TAPS calorimeters. It aimed at the in-medium properties of the S 11(1535) nucleon resonance and the study of the absorption properties of nuclear matter for η -mesons. Careful consideration was given to contributions from ηπ final states and secondary production mechanisms of η -mesons, e.g. from inelastic π N reactions of intermediate pions. The analysis of the mass number scaling shows that the nuclear absorption cross-section σ_{{Nη}}^{} for η -mesons is constant over a wide range of the η momentum. The comparison of the excitation functions to data off the deuteron and to calculations in the framework of a BUU model show no unexplained in-medium modifications of the S 11(1535).

  14. Enhanced photoproduction of hydrogen peroxide by humic substances in the presence of phenol electron donors.

    PubMed

    Zhang, Yi; Simon, Kelli A; Andrew, Andrea A; Del Vecchio, Rossana; Blough, Neil V

    2014-11-04

    Addition of a series of phenol electron donors to solutions of humic substances (HS) enhanced substantially the initial rates of hydrogen peroxide (H2O2) photoproduction (RH2O2), with enhancement factors (EF) ranging from a low of ∼3 for 2,4,6-trimethylphenol (TMP) to a high of ∼15 for 3,4-dimethoxyphenol (DMOP). The substantial inhibition of the enhanced RH2O2 following borohydride reduction of the HS, as well as the dependence of RH2O2 on phenol and dioxygen concentrations are consistent with a mechanism in which the phenols react with the triplet excited states of (aromatic) ketones within the HS to form initially a phenoxy and ketyl radical. The ketyl radical then reacts rapidly with dioxygen to regenerate the ketone and form superoxide (O2-), which subsequently dismutates to H2O2. However, as was previously noted for the photosensitized loss of TMP, the incomplete inhibition of the enhanced RH2O2 following borohydride reduction suggests that there may remain another pool of oxidizing triplets. The results demonstrate that H2O2 can be generated through an additional pathway in the presence of sufficiently high concentrations of appropriate electron donors through reaction with the excited triplet states of aromatic ketones and possibly of other species such as quinones. However, in some cases, the much lower ratio of H2O2 produced to phenol consumed suggests that secondary reactions could alter this ratio significantly.

  15. Different vertex parameterizations and propagators for the Δ contribution in π-photoproduction

    NASA Astrophysics Data System (ADS)

    Quirós, J. J.; Barbero, C.; Jaramillo, D. E.; Mariano, A.

    2017-04-01

    We evaluate the total cross section for the π-photoproduction process and analyze the behavior of the {{Δ }}(1232) resonance contribution when the photon energy is increased from threshold up to 0.7 GeV. Within this energy range we compare two different parameterizations for the γ N{{Δ }} vertex: the normal parity and the covariant multipole decomposition ones. For completeness, we also compare different versions for the Δ propagator: the first is the dressed propagator obtained including one-loop self-energy contributions (EXACT), the second is the complex mass scheme which consists in replacing {{m}}{{Δ }}\\to {{m}}{{Δ }}-{{i}}{{{Γ }}}{{Δ }}/2 in the bare propagator, and the third is an intermediate approximation between the two previous ones (EXCMS). We conclude that, in order to extend the present calculation to include more energetic resonances in the future and to obtain non-divergent results for the total cross section we will need to use the MD parametrization and the EXCMS propagator.

  16. Scalar isovector resonance photoproduction through the final state meson-meson interactions

    NASA Astrophysics Data System (ADS)

    Bibrzycki, Łukasz; Kamiński, Robert

    2016-08-01

    We construct the amplitudes of πη photoproduction taking into account the effects of the πη-KK¯ interchannel coupling. The idea of our model is to describe the scalar isovectors as dynamically produced in the final state while the initial stage of the reaction being described in terms of meson exchanges. Meson loops which arise this way include not only pseudoscalars but also vector mesons. These amplitudes are used to calculate the S-wave cross-sections and mass distributions in the πη effective mass region corresponding to the scalar resonances a0(980) and a0(1450). The values we obtained for a0(980) are comparable with predictions of other models while the cross-section for a0(1450) is about an order of magnitude larger than prediction based on the quark model. We show that the amplitudes with loops containing vector mesons calculated in the on-shell approximation are not suppressed in contrast to amplitudes containing only pseudoscalar loops. We also estimate the cross-sections for the P- and D-waves in the πη channel.

  17. Millisecond Fourier-transform infrared difference spectra of bacteriorhodopsin's M412 photoproduct.

    PubMed Central

    Braiman, M S; Ahl, P L; Rothschild, K J

    1987-01-01

    We have obtained room-temperature transient infrared difference spectra of the M412 photoproduct of bacteriorhodopsin (bR) by using a "rapid-sweep" Fourier-transform infrared (FT-IR) technique that permits the collection of an entire spectrum (extending from 1000 to 2000 cm-1 with 8-cm-1 resolution) in 5 ms. These spectra exhibit less than 10(-4) absorbance unit of noise, even utilizing wet samples containing approximately 10 pmol of bR in the measuring beam. The bR----M transient difference spectrum is similar to FT-IR difference spectra previously obtained under conditions where M decay was blocked (low temperature or low humidity). In particular, the transient spectrum exhibits a set of vibrational difference bands that were previously attributed to protonation changes of several tyrosine residues on the basis of isotopic derivative spectra of M at low temperature. Our rapid-sweep FT-IR spectra demonstrate that these tyrosine/tyrosinate bands are also present under more physiological conditions. Despite the overall similarity to the low-temperature and low-humidity spectra, the room-temperature bR----M transient difference spectrum shows significant additional features in the amide I and amide II regions. These features' presence suggests that a small alteration of the protein backbone accompanies M formation under physiological conditions and that this conformational change is inhibited in the absence of liquid water. PMID:3474649

  18. Analysis of recent CLAS data on Σ*(1385) photoproduction off a neutron target

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Yun; He, Jun; Haberzettl, Helmut

    2016-04-01

    Based on recent experimental data obtained by the CLAS Collaboration, the Σ (1385 ) photoproduction off a neutron target at laboratory photon energies Eγ up to 2.5 GeV is investigated in an effective Lagrangian approach including s -, u -, and t -channel Born-term contributions. The present calculation does not take into account any explicit s -channel baryon-resonance contributions; however, in the spirit of duality, we include t -channel exchanges of mesonic Regge trajectories. The onset of the Regge regime is controlled by smoothly interpolating between Feynman-type single-meson exchanges and full-fledged Regge-trajectory exchanges. Gauge invariance broken by the Regge treatment is fully restored by introducing contact-type interaction currents that result from the implementation of local gauge invariance in terms of generalized Ward-Takahashi identities. The cross sections for the γ n →K+Σ*(1385) - reaction are calculated and compared with experimental results from the CLAS and LEPS collaborations. Despite its simplicity, the present theoretical approach provides a good description of the main features of the data. However, the parameters fitted to the data show that the gauge-invariance-restoring contact term plays a large role, which may point to large contributions from final-state interactions.

  19. Photoproduction of π0 mesons off neutrons in the nucleon resonance region.

    PubMed

    Dieterle, M; Keshelashvili, I; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jahn, O; Jude, T C; Käser, A; Kashevarov, V L; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Werthmüller, D; Witthauer, L

    2014-04-11

    Precise angular distributions have been measured for the first time for the photoproduction of π0 mesons off neutrons bound in the deuteron. The effects from nuclear Fermi motion have been eliminated by a complete kinematic reconstruction of the final state. The influence of final-state-interaction effects has been estimated by a comparison of the reaction cross section for quasifree protons bound in the deuteron to the results for free protons and then applied as a correction to the quasifree neutron data. The experiment was performed at the tagged photon facility of the Mainz Microtron MAMI with the Crystal Ball and TAPS detector setup for incident photon energies between 0.45 and 1.4 GeV. The results are compared to the predictions from reaction models and partial-wave analyses based on data from other isospin channels. The model predictions show large discrepancies among each other and the present data will provide much tighter constraints. This is demonstrated by the results of a new analysis in the framework of the Bonn-Gatchina coupled-channel analysis which included the present data.

  20. Genotoxicity of sulcotrione pesticide and photoproducts on Allium cepa root meristem.

    PubMed

    Goujon, Eric; Sta, Chaima; Trivella, Aurélien; Goupil, Pascale; Richard, Claire; Ledoigt, Gérard

    2014-07-01

    Contamination by toxic agents in the environment has become matters of concern to agricultural countries. Sulcotrione, a triketone herbicide used to control dicotyledonous weeds in maize culture is rapidly photolyzed on plant foliage and generate two main photoproducts the xanthene-1,9-dione-3,4-dihydro-6-methylsulfonyl and 2-chloro-4-mesylbenzoic acid (CMBA). The aim of this study was to analyze the potential toxicity of the herbicide and the irradiated herbicide cocktail. Cytotoxicity and genotoxicity of non irradiated and irradiated sulcotrione were investigated in Allium cepa test. The sulcotrione irradiation was monitored under sunlight simulated conditions to reach 50% of phototransformation. Concentrations of sulcotrione in the range 5 × 10(-)(9)-5 × 10(-)(5)M were tested. Cytological analysis of root tips cells showed that both non irradiated and irradiated sulcotrione caused a dose-dependent decrease of mitotic index with higher cytotoxicity for the irradiated herbicide which can lead to 24.2% reduction of mitotic index compared to water control. Concomitantly, chromosomal aberrations were observed in A.cepa root meristems. Both non irradiated sulcotrione and irradiated sulcotrione induced a dose-dependent increase of chromosomal abnormalities frequencies to a maximal value of 33.7%. A saturating effect in anomaly frequencies was observed in meristems treated with high concentrations of non irradiated sulcotrione only. These data suggest that photolyzed sulcotrione cocktail have a greater cytotoxicity and genotoxicity than parent molecule and question about the impact of photochemical process on environment.

  1. Polarisation observables for strangeness photoproduction on a frozen spin target with CLAS at Jefferson Lab

    SciTech Connect

    Stuart Fegan

    2012-04-01

    The FROST experiment at Jefferson Lab used the CLAS detector in Hall B with the intention of performing a complete measurement of polarization observables associated with strangeness photoproduction, in combination with data from previous JLab experiments. This was achieved by utilizing the FROST polarized target in conjunction with polarized photon beams, allowing direct measurement of beam-target double polarization observables. By studying strangeness reactions, such as {gamma}p {yields} K{sup +}{Lambda}{sup 0}, it may be possible to find 'missing' baryon resonances, predicted by symmetric quark models but not observed in previous experiments, whose results are consistent with the di-quark model. It is thought these 'missing' resonances remain undiscovered because they have different coupling strengths for different reaction channels, such as the strangeness reactions, whereas the current data is dominated by studies of pN reactions. Observing these resonances therefore has important implications for our knowledge of the excited states of nucleons, and the models predicting the quark interactions within them. The G polarization observable is one of the beam-target double polarization observables, associated with a longitudinally polarized target and a linearly polarized photon beam, and its measurement for the strangeness reaction {gamma}p {yields} K{sup +}{Lambda}{sup 0} is the focus of the work presented.

  2. Hyperon Photoproduction from Polarized H and D: towards a complete N* experiment

    SciTech Connect

    Sandorfi, Andrew M.; Hoblit, S.

    2013-09-01

    New complete experiments in pseudoscalar meson photo-production are being pursued at several laboratories. Here the designation of complete refers to measurements of most if not all of the possible reaction observables, of which there are 16 involving spins of the beam, target and recoil baryon. Hyperon production to Λ or Σ{sup +} final states affords attractive opportunities, since their weak decays provide an efficient self-analysis of their polarization. When the beam and target are also polarized, the resulting triple polarization measurements determine the full suite of observables with a single target orientation. This has been a focus at Jefferson Lab in the recently completed g9/FROST and g14/HDice experiments now under analysis. Multipole analyses of γp->K{sup +}Λ have been carried out with a large though incomplete set of recently published polarization data, and the uniqueness of the extracted amplitudes has been studied. Experiments with realistically achievable uncertainties require a significantly greater number of spin asymmetries than the in-principle minimum needed for a mathematical solution of the amplitude.

  3. Threshold photoproduction of J/ ψ with the GlueX experiment

    NASA Astrophysics Data System (ADS)

    Pentchev, Lubomir; GlueX Collaboration

    2017-01-01

    The GlueX experiment uses a linearly-polarized tagged-photon beam produced by electrons from the 12 GeV CEBAF machine. The detector system is based on a 2 T solenoid and includes e.m. calorimeters and drift chambers providing full acceptance coverage. The experiment allows us, for the first time, to study J/ ψ photoproduction from the threshold, at 8 . 2 GeV, up to a photon energy of 12 GeV. Results from the recent commissioning run, where we took 25 billion triggers, will be presented. The precise knowledge of the beam energy, combined with the recoil proton reconstruction and the identification of the J/ ψ decay products, e+/e-, allows us to achieve a high mass resolution. With the data from the upcoming physics runs, we expect to have enough statistics to be able to distinguish between different production mechanisms. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.

  4. DNA repair of a single UV photoproduct in a designed nucleosome

    SciTech Connect

    Kosmoskil, Joseph V.; Ackerman, Eric J. ); Smerdon, Michael J.

    2001-08-28

    Eukaryotic DNA repair enzymes must interact with the architectural hierarchy of chromatin. The challenge of finding damaged DNA complexed with histone proteins in nucleosomes is complicated by the need to maintain local chromatin structures involved in regulating other DNA processing events. The heterogeneity of lesions induced by DNA-damaging agents has led us to design homogeneously damaged substrates to directly compare repair of naked DNA with that of nucleosomes. Here we report that nucleotide excision repair in Xenopus nuclear extracts can effectively repair a single UV radiation photoproduct located 5 bases from the dyad center of a positioned nucleosome, although the nucleosome is repaired at about half the rate at which the naked DNA fragment is. Extract repair within the nucleosome is > 50-fold more rapid than either enzymatic photoreversal or endonuclease cleavage of the lesion in vitro. Furthermore, nucleosome formation occurs (after repair) only on damaged naked DNA ( 165-bp fragments) during a 1-h incubation in these extracts, even in the presence of a large excess of undamaged DNA. This is an example of selective nucleosome assembly by Xenopus nuclear extracts on a short linear DNA fragment containing a DNA lesion.

  5. φ-meson Photoproduction By Using a Beam of Linearly-Polarized Photons

    NASA Astrophysics Data System (ADS)

    Salamanca, Julian; Cole, Philip

    2007-05-01

    The observables afforded by linearly-polarized photons provide the necessary means towards delineating the contributions of the various hadronic processes, which give rise to vector meson photoproduction. And in particular, We shall describe how φ meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal will be measure the γ p ->φp reaction, with φ->K^+K^-, in the photon energy range of 1.7G to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory (Newport News, VA). The data were collected during the g8b run in the summer of 2005. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.NWS07.B2.5

  6. Polarization observables in the photoproduction of φ mesons with linearly polarized photons

    NASA Astrophysics Data System (ADS)

    Salamanca, Julián; Cole, Philip L.; CLAS Collaboration

    2012-04-01

    Polarization observables from vector meson photoproduction by linearly-polarized photons can be expressed in terms of bilinear combinations of helicity amplitudes parameterized by the Spin Density Matrix Elements (SDMEs). These SDMEs, which are reconstructed from the measured polarization observables, give straightforward relations for understanding the nature of the parity exchange at threshold energies, as well as for extracting signatures of the Okubo-Zweig-Iizuka violation. This paper will show our measurements of the SDMEs for reaction γp→φp from the g8b experimental dataset taken with the CLAS detector in Hall B of Jefferson Lab. In particular, we have extracted polarization observables from two separate coherent peak settings covering the respective photon energy ranges: 1.7 to 1.9 GeV (momentum transfer squared t range of -1.2 to -0.25 GeV2) and 1.9 to 2.1 GeV (t range of -1.4 to -0.25 GeV2).

  7. Prompt photon photoproduction at HERA within the framework of the quark Reggeization hypothesis

    NASA Astrophysics Data System (ADS)

    Saleev, V. A.

    2008-12-01

    We study the inclusive production of isolated prompt photons within the framework of the quasi-multi-Regge-kinematic approach, applying the quark Reggeization hypothesis. We describe accurately and without free parameters the transverse momentum and pseudorapidity spectra of prompt photons in the inclusive photoproduction at the HERA Collider. It is shown that the main mechanism of the inclusive prompt photon production in the γp collisions is the fusion of a Reggeized quark (antiquark) from the proton and a collinear antiquark (quark) from the photon into a photon, via the effective Reggeon-quark-gamma vertex. The fragmentation of the quark, which is produced via the gamma-Reggeon-quark and quark-Reggeon-quark vertices, into a photon is strongly suppressed by the isolation cone condition and it gives a significant contribution in the region of a large negative pseudorapidity only. At the stage of numerical calculations we use the Kimber-Martin-Ryskin prescription for unintegrated quark and gluon distribution functions, with the following collinear parton densities as input: Martin-Roberts-Stirling-Thorne for a proton and Glück-Reya-Vogt for a photon.

  8. Photoproduction of η mesons from the neutron: Cross sections and double polarization observable E

    NASA Astrophysics Data System (ADS)

    Witthauer, L.; Dieterle, M.; Afzal, F.; Anisovich, A. V.; Bantes, B.; Bayadilov, D.; Beck, R.; Bichow, M.; Brinkmann, K.-T.; Böse, S.; Challand, Th.; Crede, V.; Dutz, H.; Eberhardt, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Friedrich, St.; Frommberger, F.; Funke, Ch.; Goertz, St.; Gottschall, M.; Gridnev, A.; Grüner, M.; Gutz, E.; Hammann, D.; Hammann, Ch.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, Ph.; Honisch, Ch.; Jude, T.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Kammer, S.; Käser, A.; Keshelashvili, I.; Klassen, P.; Kleber, V.; Klein, F.; Koop, K.; Krusche, B.; Lang, M.; Lopatin, I.; Mahlberg, Ph.; Makonyi, K.; Metag, V.; Meyer, W.; Müller, J.; Müllers, J.; Nanova, M.; Nikonov, V.; Piontek, D.; Reicherz, G.; Rostomyan, T.; Sarantsev, A.; Schmidt, Ch.; Schmieden, H.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thiel, A.; Thoma, U.; Urban, M.; van Pee, H.; Walford, N. K.; Walther, D.; Wendel, Ch.; Werthmüller, D.; Wilson, A.; Winnebeck, A.

    2017-03-01

    Results from measurements of the photoproduction of η mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron accelerator ELSA in Bonn using the η→ 3π0→ 6γ decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. The results confirm earlier measurements from Bonn and the MAMI facility in Mainz about the existence of a narrow structure in the excitation function of γ n→ nη. The current angular distributions show a forward-backward asymmetry, which was previously not seen, but was predicted by model calculations including an additional narrow P_{11} state. Furthermore, data obtained with a longitudinally polarized, deuterated butanol target and a circularly polarized photon beam were analyzed to determine the double polarization observable E. Both data sets together were also used to extract the helicity-dependent cross sections σ_{1/2} and σ_{3/2}. The narrow structure in the excitation function of γ n→ nη appears associated with the helicity-1/2 component of the reaction.

  9. Pion photoproduction on nucleons in a covariant hadron-exchange model

    SciTech Connect

    Vladimir Pascalutsa; John A. Tjon

    2004-08-01

    We present a relativistic dynamical model of pion photoproduction on the nucleon in the resonance region. It offers several advances over the existing approaches. The model is obtained by extending our {pi} N-scattering description to the electromagnetic channels. The resulting photopion amplitude is thus unitary in the {pi}N, {gamma}N channel space, Watson's theorem is exactly satisfied. At this stage we have included the pion, nucleon, {Delta}(1232)-resonance degrees of freedom. The {rho} and {omega} meson exchanges are also included, but play a minor role in the considered energy domain (up to {radical}s = 1.5 GeV). In this energy range the model provides a good description of all the important multipoles. We have allowed for only two free parameters--the photocouplings of the {Delta}-resonance. These couplings are adjusted to reproduce the strength of corresponding resonant-multipoles M{sub 1+} and E{sub 1+} at the resonance position. We then obtain R{sub EM} = 3.8 {+-} 1.6% for the E2/M1 ratio, in a qualitative agreement with other dynamical models.

  10. Low-energy {omega} ({yields}{pi}{sup 0}{gamma}) meson photoproduction in the nucleus

    SciTech Connect

    Das, Swapan

    2011-06-15

    The {pi}{sup 0{gamma}} invariant mass distribution spectra in the ({gamma},{pi}{sup 0{gamma}}) reaction were measured by the TAPS/ELSA Collaboration to look for the hadron parameters of the {omega} meson in the Nb nucleus. We study the mechanism for this reaction, where we consider that the elementary reaction in the Nb nucleus proceeds as {gamma}N{yields}{omega}N;{omega}{yields}{pi}{sup 0}{gamma}. The {omega}-meson photoproduction amplitude for this reaction is extracted from the measured four-momentum transfer distribution in the {gamma}p{yields}{omega}p reaction. The propagation of the {omega} meson and the distorted wave function for the {pi}{sup 0} meson in the final state are described by the eikonal form. The {omega} and {pi}{sup 0} mesons' nucleus optical potentials, appearing in the {omega} meson propagator and {pi}{sup 0} meson distorted wave function respectively, are estimated using the t{rho} approximation. The effects of pair correlation and color transparency are also studied. The calculated results do not show medium modification for the {omega} meson produced in the nucleus for momentum greater than 200 MeV. It occurs because the {omega} meson predominantly decays outside the nucleus. The dependence of the cross section on the final-state interaction is also investigated. The broadening of the {omega}-meson mass distribution spectra is shown to occur due to the large resolution width associated with the detector used in the experiment.

  11. Carbon monoxide photoproduction: implications for photoreactivity of Arctic permafrost-derived soil dissolved organic matter.

    PubMed

    Hong, Jun; Xie, Huixiang; Guo, Laodong; Song, Guisheng

    2014-08-19

    Apparent quantum yields of carbon monoxide (CO) photoproduction (AQY(CO)) for permafrost-derived soil dissolved organic matter (SDOM) from the Yukon River Basin and Alaska coast were determined to examine the dependences of AQY(CO) on temperature, ionic strength, pH, and SDOM concentration. SDOM from different locations and soil depths all exhibited similar AQY(CO) spectra irrespective of soil age. AQY(CO) increased by 68% for a 20 °C warming, decreased by 25% from ionic strength 0 to 0.7 mol L(-1), and dropped by 25-38% from pH 4 to 8. These effects combined together could reduce AQY(CO) by up to 72% when SDOM transits from terrestrial environemnts to open-ocean conditions during summer in the Arctic. A Michaelis-Menten kinetics characterized the influence of SDOM dilution on AQY(CO) with a very low substrate half-saturation concentration. Generalized global-scale relationships between AQY(CO) and salinity and absorbance demostrate that the CO-based photoreactivity of ancient permaforst SDOM is comparable to that of modern riverine DOM and that the effects of the physicochemical variables revealed here alone could account for the seaward decline of AQY(CO) observed in diverse estuarine and coastal water bodies.

  12. Measurement of inelastic J/ψ and ψ' photoproduction at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brümmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Göttlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Hüttmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.-P.; Januschek, F.; Jones, T. W.; Jüngst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J. F.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I.-A.; Mergelmeyer, S.; Miglioranzi, S.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Morris, J. D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schönberg, V.; Schörner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terrón, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vázquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Walczak, R.; Wan Abdullah, W. A. T.; Whitmore, J. J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagües-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zabiegalov, O.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D. S.

    2013-02-01

    The cross sections for inelastic photoproduction of J/ψ and ψ' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb-1 collected in the period 1996-2007. The ψ' to J/ψ cross section ratio was measured in the range 0 .55 < z < 0 .9 and 60 < W < 190 GeV as a function of W, z and p T . Here W denotes the photon-proton centre-of-mass energy, z is the fraction of the incident photon energy carried by the meson and p T is the transverse momentum of the meson with respect to the beam axis. The J/ψ cross sections were measured for 0 .1 < z < 0 .9, 60 < W < 240 GeV and p T > 1 GeV. Theoretical predictions within the non-relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the k T -factorisation approach.

  13. Studies of $\\Lambda n$ interaction through polarization observables for final-state interactions in exclusive $\\Lambda$ photoproduction off the deuteron

    SciTech Connect

    Ilieva, Yordanka; Cao, Tongtong; Zachariou, Nicholas

    2016-06-01

    Theoretical studies suggest that experimental observables for hyperon production reactions can place stringent constraints on the free parameters of hyperon-nucleon potentials, which are critical for the understanding of hypernuclear matter and neutron stars. Here we present preliminary experimental results for the polarization observables S, Py, Ox, Oz, Cx, and Cz for final-state interactions (FSI) in exclusive L photoproduction off the deuteron. The observables were obtained from data collected during the E06-103 (g13) experiment with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Lab. The g13 experiment ran with unpolarized deuteron target and circularly- and linearly-polarized photon beams with energies between 0.5 GeV and 2.5 GeV and collected about 51010 events with multiple charged particles in the final state. To select the reaction of interest, the K+ and the L decay products, a proton and a negative pion, were detected in the CLAS. The missing-mass technique was used to identify exclusive hyperon photoproduction events. Final-state interaction events were selected by requesting that the reconstructed neutron has a momentum larger than 200 MeV/c. The large statistics of E06-103 provided statistically meaningful FSI event samples, which allow for the extraction of one- and two-fold differential single- and double-polarization observables. Here we present preliminary results for a set of six observables for photon energies between 0.9 GeV and 2.3 GeV and for several kinematic variables in the Ln center-of-mass frame. Our results are the very first estimates of polarization observables for FSI in hyperon photoproduction and will be used to constrain the free parameters of hyperon-nucleon potentials.

  14. Parameterization of Highly Charged Metal Ions Using the 12-6-4 LJ-Type Nonbonded Model in Explicit Water

    PubMed Central

    2015-01-01

    Highly charged metal ions act as catalytic centers and structural elements in a broad range of chemical complexes. The nonbonded model for metal ions is extensively used in molecular simulations due to its simple form, computational speed, and transferability. We have proposed and parametrized a 12-6-4 LJ (Lennard-Jones)-type nonbonded model for divalent metal ions in previous work, which showed a marked improvement over the 12-6 LJ nonbonded model. In the present study, by treating the experimental hydration free energies and ion–oxygen distances of the first solvation shell as targets for our parametrization, we evaluated 12-6 LJ parameters for 18 M(III) and 6 M(IV) metal ions for three widely used water models (TIP3P, SPC/E, and TIP4PEW). As expected, the interaction energy underestimation of the 12-6 LJ nonbonded model increases dramatically for the highly charged metal ions. We then parametrized the 12-6-4 LJ-type nonbonded model for these metal ions with the three water models. The final parameters reproduced the target values with good accuracy, which is consistent with our previous experience using this potential. Finally, tests were performed on a protein system, and the obtained results validate the transferability of these nonbonded model parameters. PMID:25145273

  15. Effect of Electron Beam Freeform Fabrication (EBF3) Processing Parameters on Composition of Ti-6-4

    NASA Technical Reports Server (NTRS)

    Lach, Cynthia L.; Taminger, Karen; Schuszler, A. Bud, II; Sankaran, Sankara; Ehlers, Helen; Nasserrafi, Rahbar; Woods, Bryan

    2007-01-01

    The Electron Beam Freeform Fabrication (EBF3) process developed at NASA Langley Research Center was evaluated using a design of experiments approach to determine the effect of processing parameters on the composition and geometry of Ti-6-4 deposits. The effects of three processing parameters: beam power, translation speed, and wire feed rate, were investigated by varying one while keeping the remaining parameters constant. A three-factorial, three-level, fully balanced mutually orthogonal array (L27) design of experiments approach was used to examine the effects of low, medium, and high settings for the processing parameters on the chemistry, geometry, and quality of the resulting deposits. Single bead high deposits were fabricated and evaluated for 27 experimental conditions. Loss of aluminum in Ti-6-4 was observed in EBF3 processing due to selective vaporization of the aluminum from the sustained molten pool in the vacuum environment; therefore, the chemistries of the deposits were measured and compared with the composition of the initial wire and base plate to determine if the loss of aluminum could be minimized through careful selection of processing parameters. The influence of processing parameters and coupling between these parameters on bulk composition, measured by Direct Current Plasma (DCP), local microchemistries determined by Wavelength Dispersive Spectrometry (WDS), and deposit geometry will also be discussed.

  16. Parameterization of highly charged metal ions using the 12-6-4 LJ-type nonbonded model in explicit water.

    PubMed

    Li, Pengfei; Song, Lin Frank; Merz, Kenneth M

    2015-01-22

    Highly charged metal ions act as catalytic centers and structural elements in a broad range of chemical complexes. The nonbonded model for metal ions is extensively used in molecular simulations due to its simple form, computational speed, and transferability. We have proposed and parametrized a 12-6-4 LJ (Lennard-Jones)-type nonbonded model for divalent metal ions in previous work, which showed a marked improvement over the 12-6 LJ nonbonded model. In the present study, by treating the experimental hydration free energies and ion-oxygen distances of the first solvation shell as targets for our parametrization, we evaluated 12-6 LJ parameters for 18 M(III) and 6 M(IV) metal ions for three widely used water models (TIP3P, SPC/E, and TIP4PEW). As expected, the interaction energy underestimation of the 12-6 LJ nonbonded model increases dramatically for the highly charged metal ions. We then parametrized the 12-6-4 LJ-type nonbonded model for these metal ions with the three water models. The final parameters reproduced the target values with good accuracy, which is consistent with our previous experience using this potential. Finally, tests were performed on a protein system, and the obtained results validate the transferability of these nonbonded model parameters.

  17. Light Vector Meson Photoproduction off of H at Jefferson Lab and rho-omega Interference in the Leptonic Decay Channel

    SciTech Connect

    Chaden Djalali

    2011-12-01

    Recent studies of light vector meson production in heavy nuclear targets has generated interest in {rho}-{omega} interference in the leptonic e{sup +}e{sup -} decay channel. An experimental study of the elementary process provides valuable input for theoretical models and calculations. In experiment E04-005 (g12), high statistics photoproduction data has been taken in Jefferson Lab's Hall B with the Cebaf Large Acceptance Spectrometer (CLAS). The invariant mass spectrum is fitted with two interfering relativistic Breit-Wigner functions to determine the interference phase. Preliminary analysis indicate a measurable {rho}-{omega} interference.

  18. Determination of the linear polarization for pseudo-scalar meson photoproduction experiments in Hall-B at JLab

    NASA Astrophysics Data System (ADS)

    Sabintsev, Arthur

    2010-02-01

    The JLab CLAS g9a experiments are double polarization measurements that have accumulated photoproduction data using a linearly polarized, tagged photons incident on a longitudinally polarized, frozen spin butanol target (FROST). Linearly polarized photons were produced via coherent bremsstrahlung from an electron beam incident on an oriented diamond crystal.footnotetextU. Timm, Fortschritte der Physik, 17, 765 (1969). The analysis of the resulting coherent peaks was used to determine photon polarization which agree with phenomenological calculations.footnotetextA. Natter, et al., Nuc. Inst Meth B 211, 465 (2003). )

  19. Increased Nitrogenase-Dependent H2 Photoproduction by hup Mutants of Rhodospirillum rubrum

    PubMed Central

    Kern, Monika; Klipp, Werner; Klemme, Jobst-Heinrich

    1994-01-01

    Transposon Tn5 mutagenesis was used to isolate mutants of Rhodospirillum rubrum which lack uptake hydrogenase (Hup) activity. Three Tn5 insertions mapped at different positions within the same 13-kb EcoRI fragment (fragment E1). Hybridization experiments revealed homology to the structural hydrogenase genes hupSLM from Rhodobacter capsulatus and hupSL from Bradyrhizobium japonicum in a 3.8-kb EcoRI-ClaI subfragment of fragment E1. It is suggested that this region contains at least some of the structural genes encoding the nickel-dependent uptake hydrogenase of R. rubrum. At a distance of about 4.5 kb from the fragment homologous to hupSLM, a region with homology to a DNA fragment carrying hypDE and hoxXA from B. japonicum was identified. Stable insertion and deletion mutations were generated in vitro and introduced into R. rubrum by homogenotization. In comparison with the wild type, the resulting hup mutants showed increased nitrogenase-dependent H2 photoproduction. However, a mutation in a structural hup gene did not result in maximum H2 production rates, indicating that the capacity to recycle H2 was not completely lost. Highest H2 production rates were obtained with a mutant carrying an insertion in a nonstructural hup-specific sequence and with a deletion mutant affected in both structural and nonstructural hup genes. Thus, besides the known Hup activity, a second, previously unknown Hup activity seems to be involved in H2 recycling. A single regulatory or accessory gene might be responsible for both enzymes. In contrast to the nickel-dependent uptake hydrogenase, the second Hup activity seems to be resistant to the metal chelator EDTA. Images PMID:16349271

  20. Induction of erythroid differentiation and increased globin mRNA production with furocoumarins and their photoproducts

    PubMed Central

    Salvador, Alessia; Brognara, Eleonora; Vedaldi, Daniela; Castagliuolo, Ignazio; Brun, Paola; Zuccato, Cristina; Lampronti, Ilaria; Gambari, Roberto

    2013-01-01

    Differentiation-therapy is an important approach in the treatment of cancer, as in the case of erythroid induction in chronic myelogenous leukemia. Moreover, an important therapeutic strategy for treating beta-thalassemia and sickle-cell anemia could be the use of drugs able to induce erythroid differentiation and fetal hemoglobin (HbF) accumulation: in fact, the increased production of this type of hemoglobin can reduce the clinical symptoms and the frequency of transfusions. An important class of erythroid differentiating compounds and HbF inducers is composed by DNA-binding chemotherapeutics: however, they are not used in most instances considering their possible devastating side effects. In this contest, we approached the study of erythrodifferentiating properties of furocoumarins. In fact, upon UV-A irradiation, they are able to covalently bind DNA. Thus, the erythrodifferentiation activity of some linear and angular furocoumarins was evaluated in the experimental K562 cellular model system. Quantitative real-time reverse transcription polymerase-chain reaction assay was employed to evaluate the accumulation of different globin mRNAs. The results demonstrated that both linear and angular furocoumarins are strong inducers of erythroid differentiation of K562 cells. From a preliminary screening, we selected the most active compounds and investigated the role of DNA photodamage in their erythroid inducing activity and mechanism of action. Moreover, some cytofluorimetric experiments were carried out to better study cell cycle modifications and the mitochondrial involvement. A further development of the work was carried out studying the erythroid differentiation of photolysis products of these molecules. 5,5′-Dimethylpsoralen photoproducts induced an important increase in γ-globin gene transcription in K562 cells. PMID:23518160

  1. Near-threshold incoherent ϕ photoproduction on the deuteron: Searching for traces of a resonance

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Alvin; Yang, Shin Nan; Dong, Yu Bing

    2016-07-01

    We study the near-threshold incoherent ϕ photoproduction on the deuteron based on a model of γ N →ϕ N , consisting of Pomeron, (π ,η ) exchanges, and a JP=3 /2- resonance, which describes the low-energy γ p →ϕ p LEPS data well, including the peak in the forward differential cross section. The calculation is done up to double rescatterings, with the spin dependence of the elementary γ N →ϕ N amplitude retained throughout the calculation. The Fermi motion and final-state interactions (FSIs) are all properly treated as prescribed by realistic nucleon-nucleon interaction. The couplings of the resonance to γ n and ϕ n channels are estimated with the help of a constituent quark model. The main features of the LEPS and CLAS data are described reasonably well except for some quantitative discrepancies at very low energies and low-momentum-transfer regions. It is found that contributions of Fermi motion, p n FSI, and resonance are all indispensable in bridging the differences between the single-scattering results and the data. The off-shell rescattering is found to be important because it cancels out a large portion of the on-shell contribution. The discrepancies at low-momentum-transfer regions might be related to the binning size of the data. No peak is found to be associated with the weak resonance because it gets smeared out by the Fermi motion and FSI with the deuterium target. The problem at very-low-energy regions hints at the possible contributions from other mechanisms and should be investigated in depth with the use of recent high-statistics γ p →ϕ p data from CLAS.

  2. Sensitizing effect of Z,Z-bilirubin IXα and its photoproducts on enzymes in model solutions

    NASA Astrophysics Data System (ADS)

    Plavskii, V. Yu.; Mostovnikov, V. A.; Tret'yakova, A. I.; Mostovnikova, G. R.

    2008-05-01

    In model systems, we have studied side effects which may be induced by light during phototherapy of hyperbilirubinemia (jaundice) in newborn infants, with the aim of reducing the Z,Z-bilirubin IXα (Z,Z-BR IXα) level. We have shown that the sensitizing effect of Z,Z-BR IXα, localized at strong binding sites of the human serum albumin (HSA) macromolecule, is primarily directed at the amino acid residues of the carrier protein and does not involve the molecules of the enzyme (lactate dehydrogenase (LDH)) present in the buffer solution. The detected photodynamic damage to LDH is due to sensitization by bilirubin photoisomers, characterized by lower HSA association constants and located (in contrast to native Z,Z-BR IXα) on the surface of the HSA protein globule. Based on study of the spectral characteristics of the photoproducts of Z,Z-BR IXα and comparison of their accumulation kinetics in solution and the enzyme photo-inactivation kinetics, we concluded that the determining role in sensitized damage to LDH is played by lumirubin. The photosensitization effect depends on the wavelength of the radiation used for photoconversion of bilirubin. When (at the beginning of exposure) we make sure that identical numbers of photons are absorbed by the pigment in the different spectral ranges, the side effect is minimal for radiation corresponding to the long-wavelength edge of the bilirubin absorption band. We have shown that for a bilirubin/HSA concentration ratio >2 (when some of the pigment molecules are sorbed on the surface of the protein globule), the bilirubin can act as a photosensitizing agent for the enzyme present in solution. We discuss methods for reducing unfavorable side effects of light on the body of newborn infants during phototherapy of hyperbilirubinemia.

  3. Crystal structures of ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate.

    PubMed

    Gomes, Ligia R; Low, John Nicolson; Fernandes, Carlos; Gaspar, Alexandra; Borges, Fernanda

    2016-01-01

    The crystal structures of two chromone derivatives, viz. ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate, C19H16O4, (1), and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate C18H13FO4, (2), have been determined: (1) crystallizes with two mol-ecules in the asymmetric unit. A comparison of the dihedral angles beween the mean planes of the central chromone core with those of the substituents, an ethyl ester moiety at the 2-position and a para-substituted phenyl ring at the 6-position shows that each mol-ecule differs significantly from the others, even the two independent mol-ecules (a and b) of (1). In all three mol-ecules, the carbonyl groups of the chromone and the carboxyl-ate are trans-related. The supra-molecular structure of (1) involves only weak C-H⋯π inter-actions between H atoms of the substituent phenyl group and the phenyl group, which link mol-ecules into a chain of alternating mol-ecules a and b, and weak π-π stacking inter-actions between the chromone units. The packing in (2) involves C-H⋯O inter-actions, which form a network of two inter-secting ladders involving the carbonyl atom of the carboxyl-ate group as the acceptor for H atoms at the 7-position of the chromone ring and from an ortho-H atom of the exocyclic benzene ring. The carbonyl atom of the chromone acts as an acceptor from a meta-H atom of the exocyclic benzene ring. π-π inter-actions stack the mol-ecules by unit translation along the a axis.

  4. Differential DNA lesion formation and repair in heterochromatin and euchromatin

    PubMed Central

    Han, Chunhua; Srivastava, Amit Kumar; Cui, Tiantian; Wang, Qi-En; Wani, Altaf A.

    2016-01-01

    Discretely orchestrated chromatin condensation is important for chromosome protection from DNA damage. However, it is still unclear how different chromatin states affect the formation and repair of nucleotide excision repair (NER) substrates, e.g. ultraviolet (UV)-induced cyclobutane pyrimidine dimers (CPD) and the pyrimidine (6-4) pyrimidone photoproducts (6-4PP), as well as cisplatin-induced intrastrand crosslinks (Pt-GG). Here, by using immunofluorescence and chromatin immunoprecipitation assays, we have demonstrated that CPD, which cause minor distortion of DNA double helix, can be detected in both euchromatic and heterochromatic regions, while 6-4PP and Pt-GG, which cause major distortion of DNA helix, can exclusively be detected in euchromatin, indicating that the condensed chromatin environment specifically interferes with the formation of these DNA lesions. Mechanistic investigation revealed that the class III histone deacetylase SIRT1 is responsible for restricting the formation of 6-4PP and Pt-GG in cells, probably by facilitating the maintenance of highly condensed heterochromatin. In addition, we also showed that the repair of CPD in heterochromatin is slower than that in euchromatin, and DNA damage binding protein 2 (DDB2) can promote the removal of CPD from heterochromatic region. In summary, our data provide evidence for differential formation and repair of DNA lesions that are substrates of NER. Both the sensitivity of DNA to damage and the kinetics of repair can be affected by the underlying level of chromatin compaction. PMID:26717995

  5. Infrared collision-induced absorption by O2 near 6.4 microm for atmospheric applications: measurements and empirical modeling.

    PubMed

    Thibault, F; Menoux, V; Le Doucen, R; Rosenmann, L; Hartmann, J M; Boulet, C

    1997-01-20

    Accurate measurements of collision-induced absorption by O(2) and O(2)-N(2) mixtures in the fundamental band near 6.4 microm have been made. A Fourier-transform spectrometer was used with a resolution of 0.5 cm(-1). Absorption has been investigated in the 0-20-atm and 193-293 K pressure and temperature ranges, respectively. The current measurements confirm that the broad O(2) continuum carries small features whose attribution is not yet clear. Available experimental data in the 190-360 K temperature range have been used to build a simple, low cost computer, empirical model that is well adapted for computation of atmospheric O(2) absorption. Tests show that it is accurate, contrary to predictions of widely used atmospheric transmission codes.

  6. Hydrogen film cooling with incident and swept-shock interactions in a Mach 6.4 nitrogen free stream

    NASA Technical Reports Server (NTRS)

    Olsen, George C.; Nowak, Robert J.

    1995-01-01

    The effectiveness of slot film cooling of a flat plate in a Mach 6.4 flow with and without incident and swept oblique shock interactions was experimentally investigated. Hydrogen was the primary coolant gas, although some tests were conducted using helium as the coolant. Tests were conducted in the Calspan 48-Inch Shock Tunnel with a nitrogen flow field to preclude combustion of the hydrogen coolant gas. A two-dimensional highly instrumented model developed in a previous test series was used. Parameters investigated included coolant mass flow rate, coolant gas, local free-stream Reynolds number, incident oblique shock strength, and a swept oblique shock. Both gases were highly effective coolants in undisturbed flow; however, both incident and swept shocks degraded that effectiveness.

  7. Synthesis, spectral, thermal, optical and theoretical studies of (2E,6E)-2-benzylidene-6-(4-methoxybenzylidene)cyclohexanone.

    PubMed

    Meenatchi, V; Muthu, K; Rajasekar, M; Meenakshisundaram, Sp

    2014-01-01

    Single crystals of (2E,6E)-2-benzylidine-6-(4-methoxybenzylidine)cyclohexanone are grown by slow evaporation of ethanolic solution at room temperature. The characteristic functional groups present in the molecule are confirmed by Fourier transform infrared and Fourier transform Raman analyses. The scanning electron microscopy study reveals the surface morphology of the material. Thermogravimetric/differential thermal analysis study reveals the purity of the material and the crystal is transparent in the visible region having a lower optical cut-off at ∼487nm. The second harmonic generation efficiency of as-grown material is estimated by Kurtz and Perry technique. Optimized geometry has been derived using Hartree-Fock calculations performed at the level 6-31G (d,p) and the first-order molecular hyperpolarizability (β) is estimated. The specimen is further characterized by nuclear magnetic resonance spectroscopy.

  8. 30/20 GHz and 6/4 GHz band transponder development for communications satellite CS-3

    NASA Astrophysics Data System (ADS)

    Tanaka, Masayoshi; Nakamura, Makoto; Okamoto, Teruki; Kumazawa, Hiroyuki

    The next phase communications satellite CS-3 will be launched in 1988 as a successor to CS-2. The CS-3 is composed of two 6/4 GHz band and ten 30/20 GHz band transponders and its mission life is seven years. This paper describes the newly developed CS-3 transponder, especially a 4 GHz band 7 watt GaAs FET amplifier, Ka-band frequency single-conversion, a 30 GHz band low noise amplifier, and a 20 GHz band 10 watt TWTA. The introduction of these new technologies contributes significantly to reducing the CS-3 transponder weight and size, and to improving performance characteristics and insuring a long life.

  9. Multiple fault slip triggered above the 2016 Mw 6.4 MeiNong earthquake in Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, Mong-Han; Tung, Hsin; Fielding, Eric J.; Huang, Hsin-Hua; Liang, Cunren; Huang, Chung; Hu, Jyr-Ching

    2016-07-01

    Rapid shortening in convergent mountain belts is often accommodated by slip on faults at multiple levels in upper crust, but no geodetic observation of slip at multiple levels within hours of a moderate earthquake has been shown before. Here we show clear evidence of fault slip within a shallower thrust at 5-10 km depth in SW Taiwan triggered by the 2016 Mw 6.4 MeiNong earthquake at 15-20 km depth. We constrain the primary coseismic fault slip with kinematic modeling of seismic and geodetic measurements and constrain the triggered slip and fault geometry using synthetic aperture radar interferometry. The shallower thrust coincides with a proposed duplex located in a region of high fluid pressure and high interseismic uplift rate, and may be sensitive to stress perturbations. Our results imply that under tectonic conditions such as high-background stress level and high fluid pressure, a moderate lower crustal earthquake can trigger faults at shallower depth.

  10. Nucleotide excision repair is reduced in oral epithelial tissues compared with skin.

    PubMed

    Mitchell, David; Paniker, Lakshmi; Godar, Dianne

    2012-01-01

    Ultraviolet radiation (UVR) exposure to internal tissues for diagnostic, therapeutic and cosmetic procedures has increased dramatically over the past decade. The greatest increase in UVR exposure of internal tissues occurs in the cosmetic industry where it is combined with oxidizing agents for teeth whitening, often in conjunction with indoor tanning. To address potential carcinogenic risks of these procedures, we analyzed the formation and repair of the DNA photoproducts associated with the signature mutations of UVR. Radioimmunoassay was used to quantify the induction and repair of cyclobutane pyrimidine dimers and pyrimidine(6-4)pyrimidone photoproducts in DNA purified from three reconstructed tissues, EpiDerm(TM) , EpiGingival(TM) and EpiOral(TM) . We observed comparable levels of DNA damage in all tissues immediately after UVR exposure. In contrast, repair was significantly reduced in both oral tissues compared with EpiDerm(TM) . Our data suggest that UVR exposure of oral tissues can result in accumulation of DNA damage and increase the risk for carcinoma and melanoma of the mouth. Because NER is a broad-spectrum defense against DNA damage caused by a variety of agents in addition to UVR, our data suggest that the relatively low NER efficiency observed in oral tissues may have wide-ranging consequences in this highly exposed environment.

  11. Hydrogen peroxide photoproduction by immobilized cells of the blue-green alga Anabaena variabilis: A way to solar energy conversion

    SciTech Connect

    Morales, I.; La Rosa, F.F. de )

    1992-07-01

    A photosystem for hydrogen peroxide photoproduction formed by immobilized cells of the blue-green alga, Anabaena variabilis and the redox mediator methyl viologen is described. Hydrogen peroxide is produced in a redox catalyst cycle in which methyl viologen is reduced by electrons from water obtained by the photosynthetic apparatus of the algae using solar energy, and reoxidized by the introduction of oxygen into the solution. Hydrogen peroxide is produced during methyl viologen re-oxidation in two steps by means of the formation of superoxide. Experimental conditions for maximum photoproduction (catalyst charge, chlorophyll, and agar final concentration for cell immobilization) have been investigated using a continuous photosystem with immobilized A. variabilis as photocatalyst. Under the determined optimum conditions, the photosystem with immobilized A. variabilis is photocatalyst. Under the determined optimum conditions, the photosystem produces hydrogen peroxide at a rate of 100 {mu}moles/mg Chl{center dot}h, maintaining the production for several hours, and with an energy conversion efficiency of about 2%. Taking into account the use of hydrogen peroxide as fuel, this photosystem can be a useful tool in the storage of solar energy.

  12. Structural insights into recognition and repair of UV-DNA damage by Spore Photoproduct Lyase, a radical SAM enzyme

    PubMed Central

    Benjdia, Alhosna; Heil, Korbinian; Barends, Thomas R. M.; Carell, Thomas; Schlichting, Ilme

    2012-01-01

    Bacterial spores possess an enormous resistance to ultraviolet (UV) radiation. This is largely due to a unique DNA repair enzyme, Spore Photoproduct Lyase (SP lyase) that repairs a specific UV-induced DNA lesion, the spore photoproduct (SP), through an unprecedented radical-based mechanism. Unlike DNA photolyases, SP lyase belongs to the emerging superfamily of radical S-adenosyl-l-methionine (SAM) enzymes and uses a [4Fe–4S]1+ cluster and SAM to initiate the repair reaction. We report here the first crystal structure of this enigmatic enzyme in complex with its [4Fe–4S] cluster and its SAM cofactor, in the absence and presence of a DNA lesion, the dinucleoside SP. The high resolution structures provide fundamental insights into the active site, the DNA lesion recognition and binding which involve a β-hairpin structure. We show that SAM and a conserved cysteine residue are perfectly positioned in the active site for hydrogen atom abstraction from the dihydrothymine residue of the lesion and donation to the α-thyminyl radical moiety, respectively. Based on structural and biochemical characterizations of mutant proteins, we substantiate the role of this cysteine in the enzymatic mechanism. Our structure reveals how SP lyase combines specific features of radical SAM and DNA repair enzymes to enable a complex radical-based repair reaction to take place. PMID:22761404

  13. Strangeness Photoproduction in the γp → K0 Σ+ Reaction

    SciTech Connect

    Carnahan, Bryan

    2003-01-01

    The photoproduction reaction γp → K0 Σ+ was analyzed in the photon energy range from 1.15 to 2.35 GeV. This thesis contains the first high-statistics analysis of K0 photoproduction. Data were taken in Hall B at Jefferson Lab using tagged photons incident on a liquid hydrogen target, with all outgoing charged particles in the final states (π+ π-)(p π0) and (π+ π-)(n π+) detected by the CLAS spectrometer. As the reaction γp → K0 Σ+ is a rare process, most of the detected events are due to unwanted background reactions. Careful data fits and cross checks are required to identify the reaction being studied. To determine the acceptance for the desired reaction and the possible contamination by background processes, a detailed Monte Carlo simulation of all of these processes is performed. Data sets at beam energies of 2.445 and 3.115 GeV were studied separately and then averaged into a single data set, with much better statistical precis ion than previous measurements. Our cross sections are smaller than previous experimental data and theoretical predictions based on those data, especially in the forward angular region, but are similar in shape in the total cross section.

  14. Expression of a clostridial [FeFe]-hydrogenase in Chlamydomonas reinhardtii prolongs photo-production of hydrogen from water splitting

    DOE PAGES

    Noone, Seth; Ratcliff, Kathleen; Davis, ReAnna; ...

    2016-12-24

    The high oxygen (O2) sensitivity of green algal [FeFe]-hydrogenases is a significant limitation for the sustained production of hydrogen gas (H2) from photosynthetic water splitting. To address this limitation we replaced the native [FeFe]-hydrogenases with a more O2-tolerant clostridial [FeFe]-hydrogenase CaI in Chlamydomonas reinhardtii strain D66ΔHYD (hydA1–hydA2–) that contains insertionally inactivated [FeFe]-hydrogenases genes. Expression and translocation of CaI in D66ΔHYD led to the recovery of H2 photoproduction at ~ 20% of the rates of the wild-type parent strain D66. We show for the first time that a bacterial [FeFe]-hydrogenase can be expressed, localized and matured to a catalytically active formmore » that couples to photosynthetic electron transport in the green alga C. reinhardtii. The lower rates of O2 inactivation of CaI led to more sustained H2 photoproduction when cultures were challenged with O2 or kept under prolonged illumination at solar intensities. Lastly, these results provide new insights into the requisites for attaining photobiological H2 production from water splitting using a more O2-tolerant hydrogenase.« less

  15. Insight into the Narrow Structure in η Photoproduction on the Neutron from Helicity-Dependent Cross Sections.

    PubMed

    Witthauer, L; Dieterle, M; Abt, S; Achenbach, P; Afzal, F; Ahmed, Z; Annand, J R M; Arends, H J; Bashkanov, M; Beck, R; Biroth, M; Borisov, N S; Braghieri, A; Briscoe, W J; Cividini, F; Costanza, S; Collicott, C; Denig, A; Downie, E J; Drexler, P; Ferretti-Bondy, M I; Gardner, S; Garni, S; Glazier, D I; Glowa, D; Gradl, W; Günther, M; Gurevich, G M; Hamilton, D; Hornidge, D; Huber, G M; Käser, A; Kashevarov, V L; Kay, S; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lazarev, A B; Linturi, J M; Lisin, V; Livingston, K; Lutterer, S; MacGregor, I J D; Mancell, J; Manley, D M; Martel, P P; Metag, V; Meyer, W; Miskimen, R; Mornacchi, E; Mushkarenkov, A; Neganov, A B; Neiser, A; Oberle, M; Ostrick, M; Otte, P B; Paudyal, D; Pedroni, P; Polonski, A; Prakhov, S N; Rajabi, A; Reicherz, G; Ron, G; Rostomyan, T; Sarty, A; Sfienti, C; Sikora, M H; Sokhoyan, V; Spieker, K; Steffen, O; Strakovski, I I; Strub, Th; Supek, I; Thiel, A; Thiel, M; Thomas, A; Unverzagt, M; Usov, Yu A; Wagner, S; Walford, N K; Watts, D P; Werthmüller, D; Wettig, J; Wolfes, M; Zana, L

    2016-09-23

    The double polarization observable E and the helicity dependent cross sections σ_{1/2} and σ_{3/2} were measured for η photoproduction from quasifree protons and neutrons. The circularly polarized tagged photon beam of the A2 experiment at the Mainz MAMI accelerator was used in combination with a longitudinally polarized deuterated butanol target. The almost 4π detector setup of the Crystal Ball and TAPS is ideally suited to detect the recoil nucleons and the decay photons from η→2γ and η→3π^{0}. The results show that the narrow structure previously observed in η photoproduction from the neutron is only apparent in σ_{1/2} and hence, most likely related to a spin-1/2 amplitude. Nucleon resonances that contribute to this partial wave in η production are only N 1/2^{-} (S_{11}) and N 1/2^{+} (P_{11}). Furthermore, the extracted Legendre coefficients of the angular distributions for σ_{1/2} are in good agreement with recent reaction model predictions assuming a narrow resonance in the P_{11} wave as the origin of this structure.

  16. Insight into the Narrow Structure in η Photoproduction on the Neutron from Helicity-Dependent Cross Sections

    NASA Astrophysics Data System (ADS)

    Witthauer, L.; Dieterle, M.; Abt, S.; Achenbach, P.; Afzal, F.; Ahmed, Z.; Annand, J. R. M.; Arends, H. J.; Bashkanov, M.; Beck, R.; Biroth, M.; Borisov, N. S.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Costanza, S.; Collicott, C.; Denig, A.; Downie, E. J.; Drexler, P.; Ferretti-Bondy, M. I.; Gardner, S.; Garni, S.; Glazier, D. I.; Glowa, D.; Gradl, W.; Günther, M.; Gurevich, G. M.; Hamilton, D.; Hornidge, D.; Huber, G. M.; Käser, A.; Kashevarov, V. L.; Kay, S.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Krusche, B.; Lazarev, A. B.; Linturi, J. M.; Lisin, V.; Livingston, K.; Lutterer, S.; MacGregor, I. J. D.; Mancell, J.; Manley, D. M.; Martel, P. P.; Metag, V.; Meyer, W.; Miskimen, R.; Mornacchi, E.; Mushkarenkov, A.; Neganov, A. B.; Neiser, A.; Oberle, M.; Ostrick, M.; Otte, P. B.; Paudyal, D.; Pedroni, P.; Polonski, A.; Prakhov, S. N.; Rajabi, A.; Reicherz, G.; Ron, G.; Rostomyan, T.; Sarty, A.; Sfienti, C.; Sikora, M. H.; Sokhoyan, V.; Spieker, K.; Steffen, O.; Strakovski, I. I.; Strub, Th.; Supek, I.; Thiel, A.; Thiel, M.; Thomas, A.; Unverzagt, M.; Usov, Yu. A.; Wagner, S.; Walford, N. K.; Watts, D. P.; Werthmüller, D.; Wettig, J.; Wolfes, M.; Zana, L.; A2 Collaboration at MAMI

    2016-09-01

    The double polarization observable E and the helicity dependent cross sections σ1 /2 and σ3 /2 were measured for η photoproduction from quasifree protons and neutrons. The circularly polarized tagged photon beam of the A2 experiment at the Mainz MAMI accelerator was used in combination with a longitudinally polarized deuterated butanol target. The almost 4 π detector setup of the Crystal Ball and TAPS is ideally suited to detect the recoil nucleons and the decay photons from η →2 γ and η →3 π0. The results show that the narrow structure previously observed in η photoproduction from the neutron is only apparent in σ1 /2 and hence, most likely related to a spin-1 /2 amplitude. Nucleon resonances that contribute to this partial wave in η production are only N 1 /2- (S11) and N 1 /2+ (P11). Furthermore, the extracted Legendre coefficients of the angular distributions for σ1 /2 are in good agreement with recent reaction model predictions assuming a narrow resonance in the P11 wave as the origin of this structure.

  17. Repairing the Sickle Cell mutation. II. Effect of psoralen linker length on specificity of formation and yield of third strand-directed photoproducts with the mutant target sequence.

    PubMed

    Amosova, Olga; Broitman, Steven L; Fresco, Jacques R

    2003-08-15

    Three identical deoxyoligonucleotide third strands with a 3'-terminal psoralen moiety attached by linkers that differ in length (N = 16, 6 and 4 atoms) and structure were examined for their ability to form triplex-directed psoralen photoproducts with both the mutant T residue of the Sickle Cell beta-globin gene and the comparable wild-type sequence in linear duplex targets. Specificity and yield of UVA (365 nm) and visible (419 nm) light-induced photoadducts were studied. The total photoproduct yield varies with the linker and includes both monoadducts and crosslinks at various available pyrimidine sites. The specificity of photoadduct formation at the desired mutant T residue site was greatly improved by shortening the psoralen linker. In particular, using the N-4 linker, psoralen interaction with the residues of the non-coding duplex strand was essentially eliminated, while modification of the Sickle Cell mutant T residue was maximized. At the same time, the proportion of crosslink formation at the mutant T residue upon UV irradiation was much greater for the N-4 linker. The photoproducts formed with the wild-type target were fully consistent with its single base pair difference. The third strand with the N-4 linker was also shown to bind to a supercoiled plasmid containing the Sickle Cell mutation site, giving photoproduct yields comparable with those observed in the linear mutant target.

  18. Repairing the Sickle Cell mutation. II. Effect of psoralen linker length on specificity of formation and yield of third strand-directed photoproducts with the mutant target sequence

    PubMed Central

    Amosova, Olga; Broitman, Steven L.; Fresco, Jacques R.

    2003-01-01

    Three identical deoxyoligonucleotide third strands with a 3′-terminal psoralen moiety attached by linkers that differ in length (N = 16, 6 and 4 atoms) and structure were examined for their ability to form triplex-directed psoralen photoproducts with both the mutant T residue of the Sickle Cell β-globin gene and the comparable wild-type sequence in linear duplex targets. Specificity and yield of UVA (365 nm) and visible (419 nm) light-induced photoadducts were studied. The total photoproduct yield varies with the linker and includes both monoadducts and crosslinks at various available pyrimidine sites. The specificity of photoadduct formation at the desired mutant T residue site was greatly improved by shortening the psoralen linker. In particular, using the N-4 linker, psoralen interaction with the residues of the non-coding duplex strand was essentially eliminated, while modification of the Sickle Cell mutant T residue was maximized. At the same time, the proportion of crosslink formation at the mutant T residue upon UV irradiation was much greater for the N-4 linker. The photoproducts formed with the wild-type target were fully consistent with its single base pair difference. The third strand with the N-4 linker was also shown to bind to a supercoiled plasmid containing the Sickle Cell mutation site, giving photoproduct yields comparable with those observed in the linear mutant target. PMID:12907706

  19. Pitavastatin, a new HMG-CoA reductase inhibitor, induces phototoxicity in human keratinocytes NCTC-2544 through the formation of benzophenanthridine-like photoproducts.

    PubMed

    Viola, Giampietro; Grobelny, Pawel; Linardi, Maria Antonella; Salvador, Alessia; Dall'Acqua, Stefano; Sobotta, Łukasz; Mielcarek, Jadwiga; Dall'Acqua, Francesco; Vedaldi, Daniela; Basso, Giuseppe

    2012-03-01

    This study reports the results of an investigation of the phototoxicity mechanism induced by pitavastatin and its photoproducts, namely 6-cyclopropyl-10-fluoro-7,8-dihydrobenzo[k]phenanthridine (PP3) and 6-cyclopropyl-10-fluorobenzo[k]phenanthridine (PP4). The phototoxicity was tested in human keratinocytes cell lines NCTC-2544, and the results proved that under the same conditions, all three compounds exhibited phototoxic effects in the model tested. The reduction in cell viability was found to be both concentration- and UVA dose-dependent. A point of note is that both the photoproducts produced a dramatic decrease in cell viability with GI(50) values one order of magnitude lower compared to the parent compound. In particular, the fully aromatic derivative (PP4) showed the highest antiproliferative activity. Flow cytometric analysis indicated that pitavastatin and the photoproduct PP4 principally induced necrosis, as revealed by the large appearance of propidium iodide-positive cells and also confirmed by the rapid drop in cellular ATP levels. Further studies committed to better understanding of photoinduced cell death mechanism(s) revealed that neither pitavastatin nor PP4 induced mitochondrial depolarization or lysosomal damage, but, interestingly, extensive cell lipid membrane peroxidation along with a significant oxidation of model proteins occurred, suggesting that pitavastatin and PP4 exert their phototoxic effect mainly in the cellular membranes. The present results suggest that the phototoxicity of pitavastatin may be mediated by the formation of benzophenanthridine-like photoproducts that appear to have high potential as photosensitizers.

  20. Identification of unwanted photoproducts of cosmetic preservatives in personal care products under ultraviolet-light using solid-phase microextraction and micro-matrix solid-phase dispersion.

    PubMed

    Alvarez-Rivera, Gerardo; Llompart, Maria; Garcia-Jares, Carmen; Lores, Marta

    2015-04-17

    The photochemical transformation of widely used cosmetic preservatives including benzoates, parabens, BHA, BHT and triclosan has been investigated in this work applying an innovative double-approach strategy: identification of transformation products in aqueous photodegradation experiments (UV-light, 254nm), followed by targeted screening analysis of such photoproducts in UV-irradiated cosmetic samples. Solid-phase microextraction (SPME) was applied, using different fiber coatings, in order to widen the range of detectable photoproducts in water, whereas UV-irradiated personal care products (PCPs) containing the target preservatives were extracted by micro-matrix solid-phase dispersion (micro-MSPD). Both SPME and micro-MSPD-based methodologies were successfully optimized and validated. Degradation kinetics of parent species, and photoformation of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC-MS). Thirty nine photoproducts were detected in aqueous photodegradation experiments, being tentatively identified based on their mass spectra. Transformation pathways between structurally related by-products, consistent with their kinetic behavior were postulated. The photoformation of unexpected photoproducts such as 2- and 4-hydroxybenzophenones, and 2,8-dichlorodibenzo-p-dioxin in PCPs are reported in this work for the first time.

  1. Structural elucidation and estimation of the acute toxicity of the major UV-visible photoproduct of fludioxonil - detection in both skin and flesh samples of grape.

    PubMed

    Lassalle, Yannick; Nicol, Édith; Genty, Christophe; Bourcier, Sophie; Bouchonnet, Stéphane

    2015-06-01

    Ultraviolet (UV)-visible irradiation of fludioxonil was investigated with two photoreactors using either a mercury or xenon vapor lamp. In both cases, it led to the formation of only one photoproduct in significant amount: 2-(2,2-difluorobenzo[d][1,3]dioxol-4-yl)-2-(nitrosomethylene)-4-oxobutanenitrile, which has been characterized using Liquid Chromatography - High Resolution - Tandem Mass Spectrometry (LC-HR-MS/MS) coupling. A photolysis pathway has been proposed to rationalize its formation in degassed water. In vitro bioassays on Vibrio fischeri bacteria showed that UV-vis irradiation of an aqueous solution of fludioxonil significantly increases its toxicity. Because no other by-product was detected in significant amount, the photoproduct mentioned above may be considered mainly responsible for this increase in toxicity. Grape berries treated with a 50 ppm aqueous solution of fludioxonil were submitted to UV-visible irradiation under laboratory conditions. The fungicide and photoproduct were detected in both skin and flesh of berries, even after they have been rinsed with water. The ability of the photoproduct to pass through the fruit skin is comparable with that of fludioxonil. These results are of concern for consumers because they mean that water tap rinsing does not lead to efficient removing of both compounds.

  2. 40 CFR 180.437 - Methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate and methyl 6-(4-isopropyl-4...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-imidazolin-2-yl)-p-toluate and methyl 6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate; tolerances... Tolerances § 180.437 Methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate and methyl 6-(4... for the combined residues of the herbicide methyl...

  3. ENHANCEMENT OF THE 6.4 keV LINE IN THE INNER GALACTIC RIDGE: PROTON-INDUCED FLUORESCENCE?

    SciTech Connect

    Nobukawa, K. K.; Nobukawa, M.; Tsuru, T. G.; Tanaka, T.; Koyama, K.; Uchiyama, H.; Torii, K.; Fukui, Y.; Chernyshov, D. O.; Dogiel, V. A.

    2015-07-01

    A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this scenario, the flux should symmetrically distribute between the east and west on the plane with respect to Sagittarius A* because the stellar mass distribution determined by infrared observations is nearly symmetric. This symmetry is confirmed for the highly ionized iron line as well as the continuum emission. However, a clear excess of the neutral iron line in the near east of the Galactic center compared to the near-west side is found. The flux distribution of the excess emission well correlates with the molecular column density. The X-ray spectrum of the excess emission is described by a power-law continuum plus a 6.4 keV line with a large equivalent width of ∼1.3 keV, which is hardly explained by the low-energy electron bombardment scenario. The longitudinal and latitudinal distribution of the excess emission disfavors the X-ray irradiation, either by Sagittarius A* or by nearby X-ray binaries. Then, the low-energy proton bombardment is the most probable origin, although the high-energy density ∼80 eV cm{sup −3} in 0.1–1000 MeV is required and there is no conventional proton source in the vicinity.

  4. A temperature-induced order-disorder phase transition in a 4-substituted 4,2':6',4''-terpyridine.

    PubMed

    Granifo, Juan; Westermeyer, Marleen; Riquelme, Maricel; Gaviño, Rubén; Suárez, Sebastián; Halac, Emilia B; Baggio, Ricardo

    2015-12-01

    Crystals of 4'-(isoquinolin-4-yl)-4,2':6',4''-terpyridine (iqtp), C24H16N4, grown from an ethanol solution, undergo a reversible first-order single-crystal to single-crystal phase transition at Tc in the range 273-275 K, from a disordered higher-temperature phase [form (I)] in the space group P21/c, with one single molecule in the asymmetric unit, to an ordered lower-temperature one [form (II)] in the space group P21/n, with two independent molecules in the asymmetric unit. There is a group-subgroup relationship linking (I)-(II), due to cell doubling and the disappearance of a number of symmetry operations. In addition to X-ray diffraction, the transition has been monitored by Raman spectroscopy and differential scanning calorimetry, the latter disclosing an enthalpy change of 0.72 (6) kJ mol(-1). Variations of the unit-cell parameters with temperature between 170 and 293 K are presented. The evolution of diffraction spots in the vicinity of the transition temperature shows the coexistence of both phases, confirming the first-order character of the transition. Structural details of both phases are analyzed and intermolecular interactions compared in order to investigate the mechanism of the phase transition. A three-dimensional Hirshfeld surface analysis was performed to corroborate the significant changes in the intermolecular features.

  5. The 29 July 2014 (Mw 6.4) Southern Veracruz, Mexico Earthquake: Scenary Previous to Its Occurrence.

    NASA Astrophysics Data System (ADS)

    Yamamoto, J.

    2014-12-01

    On 29 July 2014 (10:46 UTC) a magnitude 6.4 (Mw) earthquake occurred at the southern Veracruz, Mexico region. The epicenter was preliminary located at 17.70° N and 95.63° W. It was a normal fault event with the slip on a fault that trend NNW and a focus approximately 117 km below the surface of the Gulf of Mexico costal plane. The earthquake was widely felt through centro and southern Mexico. In Oaxaca City 133 km to the south a person die of a hearth attack. No damages were reported. Most prominent moderate-sized earthquakes occurring in the southern Veracruz region since 1959 has been concentrated along two well defined seismic belts. One belt runs off the coast following nearly its contour. Here the earthquakes are shallow depth and mostly show a reverse fault mechanism. This belt of seismicity begins at the Los Tuxtlas volcanic field. Another seismic belt is located inland 70 km to the west. Here most earthquakes are of intermediate-depth (108-154 km) focus and normal faulting mechanism. The July 2014 earthquake is located near to this second seismic belt. In the present paper we discuss, within the regional geotectonic framework, the location and some aspects of the rupture process of the July 2014 earthquake.

  6. Enhancement of the 6.4 keV Line in the Inner Galactic Ridge: Proton-induced Fluorescence?

    NASA Astrophysics Data System (ADS)

    Nobukawa, K. K.; Nobukawa, M.; Uchiyama, H.; Tsuru, T. G.; Torii, K.; Tanaka, T.; Chernyshov, D. O.; Fukui, Y.; Dogiel, V. A.; Koyama, K.

    2015-07-01

    A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this scenario, the flux should symmetrically distribute between the east and west on the plane with respect to Sagittarius A* because the stellar mass distribution determined by infrared observations is nearly symmetric. This symmetry is confirmed for the highly ionized iron line as well as the continuum emission. However, a clear excess of the neutral iron line in the near east of the Galactic center compared to the near-west side is found. The flux distribution of the excess emission well correlates with the molecular column density. The X-ray spectrum of the excess emission is described by a power-law continuum plus a 6.4 keV line with a large equivalent width of ˜1.3 keV, which is hardly explained by the low-energy electron bombardment scenario. The longitudinal and latitudinal distribution of the excess emission disfavors the X-ray irradiation, either by Sagittarius A* or by nearby X-ray binaries. Then, the low-energy proton bombardment is the most probable origin, although the high-energy density ˜80 eV cm-3 in 0.1-1000 MeV is required and there is no conventional proton source in the vicinity.

  7. Post-seismic deformation of the Mw 6.4 Shonbeh earthquake (south western Iran) of April 9th, 2013

    NASA Astrophysics Data System (ADS)

    Fathian Baneh, Aram; Tolomei, Cristiano; Lugari, Alessandro; Trasatti, Elisa; Salvi, Stefano

    2016-04-01

    The study of post-seismic deformation within a region is of high significance to have a better understanding of the kinematic behavior of a seismogenic fault. We perform the Small Baseline Subset (SBAS) method to process a large number of X-Band, COSMO-SkyMed images to measure the post-seismic deformation due to the Shonbeh earthquake (Iran) of 9th April 2013 (Mw 6.4). The meizoseismal zone of the earthquake and following aftershocks' epicenters cover an area in the frontal edge of the Zagros Simply Folded Zone, in the southwest of Iran, between Kaki and Kangan anticlines. Exploiting the available dataset of images from the beginning of 2013 to mid 2014, we observe the concentration of the deformation along at least two NW- striking, southwest-dipping fault segments arranged in right-step pattern and parallel to the trend of the folds. The preliminary InSAR results illustrate the migration of the post-seismic deformation and stress relaxation from the southeastern toward the northwestern fault segments.

  8. Identification of potentially cytotoxic lesions induced by UVA photoactivation of DNA 4-thiothymidine in human cells

    PubMed Central

    Reelfs, Olivier; Macpherson, Peter; Ren, Xiaolin; Xu, Yao-Zhong; Karran, Peter; Young, Antony R.

    2011-01-01

    Photochemotherapy—in which a photosensitizing drug is combined with ultraviolet or visible radiation—has proven therapeutic effectiveness. Existing approaches have drawbacks, however, and there is a clinical need to develop alternatives offering improved target cell selectivity. DNA substitution by 4-thiothymidine (S4TdR) sensitizes cells to killing by ultraviolet A (UVA) radiation. Here, we demonstrate that UVA photoactivation of DNA S4TdR does not generate reactive oxygen or cause direct DNA breakage and is only minimally mutagenic. In an organotypic human skin model, UVA penetration is sufficiently robust to kill S4TdR-photosensitized epidermal cells. We have investigated the DNA lesions responsible for toxicity. Although thymidine is the predominant UVA photoproduct of S4TdR in dilute solution, more complex lesions are formed when S4TdR-containing oligonucleotides are irradiated. One of these, a thietane/S5-(6-4)T:T, is structurally related to the (6-4) pyrimidine:pyrimidone [(6-4) Py:Py] photoproducts induced by UVB/C radiation. These lesions are detectable in DNA from S4TdR/UVA-treated cells and are excised from DNA more efficiently by keratinocytes than by leukaemia cells. UVA irradiation also induces DNA interstrand crosslinking of S4TdR-containing duplex oligonucleotides. Cells defective in repairing (6-4) Py:Py DNA adducts or processing DNA crosslinks are extremely sensitive to S4TdR/UVA indicating that these lesions contribute significantly to S4TdR/UVA cytotoxicity. PMID:21890905

  9. A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics. [acid-base properties of titanium 6-4 surfaces

    NASA Technical Reports Server (NTRS)

    Siriwardane, R.; Wightman, J. P.

    1980-01-01

    The acid-base properties of titanium 6-4 plates (low surface area) were investigated after three different pretreatments, namely Turco, phosphate-fluoride and Pasa-Jell. A series of indicators was used and color changes were detected using diffuse reflectance visible spectroscopy. Electron spectroscopy for chemical analysis was used to examine the indicator on the Ti 6-4 surface. Specular reflectance infra-red spectroscopy was used to study the adsorption of stearic acid from cyclohexane solutions on the Ti 6-4 surface.

  10. Linearly polarised photon beams at ELSA and measurement of the beam asymmetry in π0_{} photoproduction off the proton

    NASA Astrophysics Data System (ADS)

    Elsner, D.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Ehmanns, A.; Essig, K.; Ewald, R.; Fabry, I.; Frommberger, F.; Fornet-Ponse, K.; Fuchs, M.; Funke, C.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Morales, C.; Nanova, M.; Novinski, D. V.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Sarantsev, A. V.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Walther, D.; Weinheimer, C.; Wendel, C.

    2009-03-01

    At the electron accelerator ELSA a linearly polarised tagged photon beam is produced by coherent bremsstrahlung off a diamond crystal. Orientation and energy range of the linear polarisation can be deliberately chosen by accurate positioning of the crystal with a goniometer. The degree of polarisation is determined by the form of the scattered electron spectrum. Good agreement between experiment and expectations on the basis of the experimental conditions is obtained. Polarisation degrees of ensuremath P_{γ}=40 % are typically achieved at half of the primary electron energy. The determination of ensuremath P_{γ} is confirmed by measuring the beam asymmetry, Σ , in π0_{} photoproduction and by a comparison of the results to independent measurements using laser backscattering.

  11. The photoproduction of φ-mesons off protons by using a beam of linearly polarized photons at threshold energies

    NASA Astrophysics Data System (ADS)

    Salamanca Bernal, Julian Andres

    Observables from vector meson photoproduction by linearly-polarized photons can be expressed in term of bilinear combinations of helicity amplitudes parameterized by the Spin Density Matrix Elements (SDMEs). These SDMEs give straightforward relations for understanding the nature of the parity exchange at threshold energies, as well as for extracting signatures of the Okubo-Zweig-Iizuka violation. Measurement of SDMEs for g⃗ p →φp in the photon energy range of 1.7 to 1.9 GeV (momentum transfer squared t range of -1.2 to -0.25 GeV2) and 1.9 to 2.1 GeV (t range of -1.4 to -0.25 GeV 2) from the g8b experimental data collected in the summer of 2005 in the Hall B of Jefferson Lab are reported herein.

  12. Lepton Universality Test in the Photoproduction of e-e+ Versus μ-μ+ Pairs on a Proton Target

    NASA Astrophysics Data System (ADS)

    Pauk, Vladyslav; Vanderhaeghen, Marc

    2015-11-01

    In view of the significantly different proton charge radius extracted from muonic hydrogen Lamb shift measurements as compared to electronic hydrogen spectroscopy or electron-scattering experiments, we study in this Letter the photoproduction of a lepton pair on a proton target in the limit of very small momentum transfer as a way to provide a test of the lepton universality when extracting the proton charge form factor. By detecting the recoiling proton in the γ p →l-l+p reaction, we show that a measurement of a ratio of e-e++μ-μ+ over e-e+ cross sections with an absolute precision of 7 ×1 0-4 would allow for a test to distinguish, at the 3 σ level, between the two different proton charge radii currently extracted from muonic and electronic observables.

  13. Measurement of pi+pi- Photoproduction in Double Polarization Experiments using the CLAS Spectrometer

    SciTech Connect

    Hanretty, Charles

    2007-10-01

    Spectroscopic predictions based on first principles are not possible in the non-perturbative regime of Quantum Chromodynamics (QCD) where the strong coupling constant is large. For this reason, effective theories and models have been developed to determine the masses, couplings, and decay widths of resonances. Various constituent quark models (CQMs) based on three quark degrees of freedom predict numerous baryon resonances that have not been experimentally verified and are thus “missing”. The persistent non-observation of these states would present a big problem as the models would have failed to describe physical reality. CQMs predict strong couplings of these unobserved or missing states to gammaN as well as to Neta, Neta[prime] or Deltapi(Delta-->ppi) making photoproduction experiments a promising method to find these missing resonances. Previous analyses of unpolarized data show the importance of polarization obervables because some resonances reveal themselves more clearly in the interference with more dominant amplitudes. In addition, the determination of resonant contributions based on unpolarized data is not unique and requires further constraints provided by single- and double-polarization observables in the Partial Wave Analysis (PWA). A linearly- and circularly-polarized photon beam will be incident on a frozen-spin butanol target in Jefferson Lab's Hall B CLAS detector located in Newport News, Va. This detector allows the target to be polarized both longitudinally as well as transversely giving rise to measurable polarization observables in pi+pi- photoproduction. This experiment (FROST) will shed some light on the problem of the missing baryon resonances serving to better understand the properties of these states.

  14. [Fe(CN)6]4- decorated mesoporous gelatin thin films for colorimetric detection and as sorbents of heavy metal ions.

    PubMed

    Shi, Li; Huang, Hubiao; Sun, Luwei; Lu, Yanping; Du, Binyang; Mao, Yiyin; Li, Junwei; Ye, Zhizhen; Peng, Xinsheng

    2013-09-28

    [Fe(CN)6](4-) decorated mesoporous gelatin films, acting as colorimetric sensors and sorbents for heavy metal ions, were prepared by incorporating [Fe(CN)6](4-) ions into the mesoporous gelatin films through electrostatic interaction. Gelatin-Prussian blue (PB) and gelatin-PB analogue composite films were successfully synthesized by immersing the [Fe(CN)6](4-) decorated gelatin films into aqueous solutions of metal ions, such as Fe(3+), Cu(2+), Co(2+), Pb(2+) and Cd(2+) (all as nitrates). The in situ formation process of PB or its analogues in the films was investigated using quartz crystal microbalance (QCM) measurements. According to the different colors of the PB nanoparticles and its analogues, the [Fe(CN)6](4-) decorated mesoporous gelatin films demonstrated colorimetric sensor abilities for detecting the corresponding metal ions by the naked eye with sufficient sensitivity at 1 ppm level and a quite short response time of 5 minutes. Moreover, due to the [Fe(CN)6](4-) functionality and other functional groups of gelatin itself, this [Fe(CN)6](4-) decorated mesoporous gelatin film shows a tens times higher adsorption ability for heavy metal ions in water than that of activated carbon. Due to both the efficient detection and high adsorption ability for heavy metal ions, this film has wide potential applications for the detection and purification of heavy metal ions from polluted water.

  15. Ultraviolet photolysis of HCHO: absolute HCO quantum yields by direct detection of the HCO radical photoproduct.

    PubMed

    Carbajo, Paula Gorrotxategi; Smith, Shona C; Holloway, Anne-Louise; Smith, Carina A; Pope, Francis D; Shallcross, Dudley E; Orr-Ewing, Andrew J

    2008-12-04

    Absolute quantum yields for the radical (H + HCO) channel of HCHO photolysis, Phi(HCO), have been measured for the tropospherically relevant range of wavelengths (lambda) between 300 and 330 nm. The HCO photoproduct was directly detected by using a custom-built, combined ultra-violet (UV) absorption and cavity ring down (CRD) detection spectrometer. This instrument was previously employed for high-resolution (spectral resolution approximately 0.0035 nm) measurements of absorption cross-sections of HCHO, sigma(HCHO)(lambda), and relative HCO quantum yields. Absolute Phi(HCO) values were measured at seven wavelengths, lambda = 303.70, 305.13, 308.87, 314.31, 320.67, 325.59, and 329.51 nm, using an independent calibration technique based on the simultaneous UV photolysis of HCHO and Cl(2). These Phi(HCO) measurements display greater variability as a function of wavelength than the current NASA-JPL recommendations for Phi(HCO). The absolute Phi(HCO)(lambda) determinations and previously measured sigma(HCHO)(lambda) were used to scale an extensive set of relative HCO yield measurements. The outcome of this procedure is a full suite of data for the product of the absolute radical quantum yield and HCHO absorption cross-section, Phi(HCO)(lambda)sigma(HCHO)(lambda), at wavelengths from 302.6 to 331.0 nm with a wavelength resolution of 0.005 nm. This product of photochemical parameters is combined with high-resolution solar photon flux data to calculate the integrated photolysis rate of HCHO to the radical (H + HCO) channel, J(HCO). Comparison with the latest NASA-JPL recommendations, reported at 1 nm wavelength resolution, suggests an increased J(HCO) of 25% at 0 degrees solar zenith angle (SZA) increasing to 33% at high SZA (80 degrees). The differences in the calculated photolysis rate compared with the current HCHO data arise, in part, from the higher wavelength resolution of the current data set and highlight the importance of using high-resolution spectroscopic

  16. Inhibition of semiconservative DNA synthesis in ICR 2A frog cells by pyrimidine dimers and nondimer photoproducts induced by ultraviolet radiation

    SciTech Connect

    Rosenstein, B.S.

    1984-11-01

    DNA synthesis was examined in ultraviolet (uv)-irradiated ICR 2A frog cells in which either pyrimidine dimers or nondimer photoproducts represented the major class of DNA lesions. In addition, cells were exposed to /sup 60/Co ..gamma.. rays. The cultures were pulse-labeled and the size distribution of the DNA synthesized was estimated using both sucrose gradient sedimentation and alkaline step elution. Using either of these techniques, it was found that the presence of dimers resulted in a reduction principally in the synthesis of high molecular weight (MW) DNA. In contrast, nondimer photoproducts caused a strong inhibition in the synthesis of low MW DNA, as was also observed in ..gamma..-irradiated cells. Hence the induction of pyrimidine dimers in DNA mainly affected the elongation of replicons, whereas nondimer lesions primarily caused an inhibition of replicon initiation.

  17. First Observation Of The Wavelength-Dependent Photoproduction Of The 4E,15Z Configurational Isomer Of Bilirubin Bound To Human Serum Albumin

    NASA Astrophysics Data System (ADS)

    Mc Donagh, Antony F.; Agati, Giovanni; Fusi, Franco; Pratesi, R.

    1987-07-01

    The photochemistry of bilirubin (BR) is of considerable interest because of its importance in the treatment of neonatal jaundice with visible light phototherapy. Patients are irradiated with blue, white or green fluorescent lamps to induce conversion of the unexcretable and toxic bilirubin to more polar, water-soluble and easily excreted photoproducts. The molecular mechanisms responsible for the phototherapeutic action of light on jaundiced babies have not jet been completely elucidated.

  18. The effects of ultraviolet light on aspects of DNA metabolism in cell lines derived from plodia interpunctella and Trichoplusia ni

    SciTech Connect

    Styer, S.C.

    1991-01-01

    Insect cells are significantly more resistant to the lethal effects of 254 nm ultraviolet light (UV) than mammalian cells. The predominant photoproduct produced by UV is the (5-6) cyclobutyl pyrimidine dimer. There is controversy whether this lesion, or another, the pyrimidine (6-4) pyrimidone, is responsible for the biological effects of UV. Insect cells contain a photolyase which selectively removes the (5-6), but not the (6-4) lesion, so that the relative roles of these lesions can be studied. Insect cell lines derived from the cabbage looper and the Indian meal moth were exposed to UV and analyzed for their ability to incorporate [sup 3]H-thymidine. After exposure, cells from the Indian meal moth exhibited a rapid and prolonged depression in the rate of thymidine incorporation, whereas cells from the cabbage looper showed only a slight drop in incorporation and a rapid recovery. The extent of depression in thymidine incorporation was not correlated to the amount of cell killing by UV in these cell lines. Blockage of fork progression was correlated to the depression in thymidine incorporation. Photoreactivation did not entirely relieve blockage, depression in thymidine incorporation or cell killing, indicating that although the (5-6) dimer appears to be the major lesion responsible for these effects, other lesions, such as the (6-4) photoproduct, may play a role. In addition, activation of alternative sites of replicon initiation appeared to correlate with the depression in thymidine incorporation and the excision capabilities in these cells. The resistance to UV in these insect cells compared to mammalian cells may be due to their ability to rapidly remove the (5-6) lesion, which is the critical lesion in these insect cells.

  19. Integration and scaling of UV-B radiation effects on plants: from DNA to leaf

    PubMed Central

    Suchar, Vasile Alexandru; Robberecht, Ronald

    2015-01-01

    A process-based model integrating the effects of UV-B radiation through epidermis, cellular DNA, and its consequences to the leaf expansion was developed from key parameters in the published literature. Enhanced UV-B radiation-induced DNA damage significantly delayed cell division, resulting in significant reductions in leaf growth and development. Ambient UV-B radiation-induced DNA damage significantly reduced the leaf growth of species with high relative epidermal absorbance at longer wavelengths and average/low pyrimidine cyclobutane dimers (CPD) photorepair rates. Leaf expansion was highly dependent on the number of CPD present in the DNA, as a result of UV-B radiation dose, quantitative and qualitative absorptive properties of epidermal pigments, and repair mechanisms. Formation of pyrimidine-pyrimidone (6-4) photoproducts (6-4PP) has no effect on the leaf expansion. Repair mechanisms could not solely prevent the UV-B radiation interference with the cell division. Avoidance or effective shielding by increased or modified qualitative epidermal absorptance was required. Sustained increased UV-B radiation levels are more detrimental than short, high doses of UV-B radiation. The combination of low temperature and increased UV-B radiation was more significant in the level of UV-B radiation-induced damage than UV-B radiation alone. Slow-growing leaves were more affected by increased UV-B radiation than fast-growing leaves. PMID:26257869

  20. Searching for novel photolyases in UVC-resistant Antarctic bacteria.

    PubMed

    Marizcurrena, Juan José; Morel, María A; Braña, Victoria; Morales, Danilo; Martinez-López, Wilner; Castro-Sowinski, Susana

    2017-03-01

    Ultraviolet (UV) light irradiation has serious consequences for cell survival, including DNA damage by formation of cyclobutane pyrimidine dimers (CPD) and pyrimidine (6,4) pyrimidone photoproducts. In general, the Nucleotide Excision Repair pathway repairs these lesions; however, all living forms, except placental mammals and some marsupials, produce a flavoprotein known as photolyase that directly reverses these lesions. The aim of this work was the isolation and identification of Antarctic UVC-resistant bacteria, and the search for novel photolyases. Two Antarctic water samples were UVC-irradiated (254 nm; 50-200 J m(- 2)) and 12 UVC-resistant bacteria were isolated and identified by 16S rDNA amplification/analysis as members of the genera Pseudomonas, Janthinobacterium, Flavobacterium, Hymenobacter and Sphingomonas. The UVC 50% lethal dose and the photo-repair ability of isolates were analyzed. The occurrence of photolyase coding sequences in Pseudomonas, Hymenobacter and Sphingomonas isolates were searched by PCR or by searching in the draft DNA genome. Results suggest that Pseudomonas and Hymenobacter isolates produce CDP-photolyases, and Sphingomonas produces two CPD-photolyases and a 6,4-photolyase. Results suggest that the Antarctic environment is an important source of genetic material for the identification of novel photolyase genes with potential biotechnological applications.

  1. Integration and scaling of UV-B radiation effects on plants: from DNA to leaf.

    PubMed

    Suchar, Vasile Alexandru; Robberecht, Ronald

    2015-07-01

    A process-based model integrating the effects of UV-B radiation through epidermis, cellular DNA, and its consequences to the leaf expansion was developed from key parameters in the published literature. Enhanced UV-B radiation-induced DNA damage significantly delayed cell division, resulting in significant reductions in leaf growth and development. Ambient UV-B radiation-induced DNA damage significantly reduced the leaf growth of species with high relative epidermal absorbance at longer wavelengths and average/low pyrimidine cyclobutane dimers (CPD) photorepair rates. Leaf expansion was highly dependent on the number of CPD present in the DNA, as a result of UV-B radiation dose, quantitative and qualitative absorptive properties of epidermal pigments, and repair mechanisms. Formation of pyrimidine-pyrimidone (6-4) photoproducts (6-4PP) has no effect on the leaf expansion. Repair mechanisms could not solely prevent the UV-B radiation interference with the cell division. Avoidance or effective shielding by increased or modified qualitative epidermal absorptance was required. Sustained increased UV-B radiation levels are more detrimental than short, high doses of UV-B radiation. The combination of low temperature and increased UV-B radiation was more significant in the level of UV-B radiation-induced damage than UV-B radiation alone. Slow-growing leaves were more affected by increased UV-B radiation than fast-growing leaves.

  2. Insights into the Activity Change of Spore Photoproduct Lyase Induced by Mutations at a Peripheral Glycine Residue

    PubMed Central

    Yang, Linlin; Li, Lei

    2017-01-01

    UV radiation triggers the formation of 5-thyminyl-5,6-dihydrothymine, i.e., the spore photoproduct (SP), in the genomic DNA of bacterial endospores. These SPs, if not repaired in time, may lead to genome instability and cell death. SP is mainly repaired by spore photoproduct lyase (SPL) during spore outgrowth via an unprecedented protein-harbored radical transfer pathway that is composed of at least a cysteine and two tyrosine residues. This mechanism is consistent with the recently solved SPL structure that shows all three residues are located in proximity and thus able to participate in the radical transfer process during the enzyme catalysis. In contrast, an earlier in vivo mutational study identified a glycine to arginine mutation at the position 168 on the B. subtilis SPL that is >15 Å away from the enzyme active site. This mutation appears to abolish the enzyme activity because endospores carrying this mutant were sensitive to UV light. To understand the molecular basis for this rendered enzyme activity, we constructed two SPL mutations G168A and G168R, examined their repair of dinucleotide SP TpT, and found that both mutants exhibit reduced enzyme activity. Comparing with the wildtype (WT) SPL enzyme, the G168A mutant slows down the SP TpT repair by 3~4-fold while the G168R mutant by ~ 80-fold. Both mutants exhibit a smaller apparent (DV) kinetic isotope effect (KIE) but a bigger competitive (DV/K) KIE than that by the WT SPL. Moreover, the G168R mutant also produces a large portion of the abortive repair product TpT-SO2−; the formation of which indicates that cysteine 141 is no longer well positioned as the H-donor to the thymine allylic radical intermediate. All these data imply that the mutation at the remote glycine 168 residue alters the enzyme 3D structure, subsequently reducing the SPL activity by changing the positions of the essential amino acids involved in the radical transfer process.

  3. Charm photoproduction at 20 GeV including preliminary lifetime results with improved optical resolution

    SciTech Connect

    Colley, D.C.; Brick, D.; Bacon, T.C.; Cohn, H.O.; Franek, B.; Armenteros, R.; Abe, K.; Kafka, T.; Bingham, H.H.; Brau, J.E.

    1984-07-01

    Sixty five charm events have been observed in an exposure, during 1983, of the SLAC Hybrid Facility (SHF) to a backward scattered laser beam. Preliminary results for the charmed meson lifetimes have been obtained based on 19 neutral and 22 charged decays thereby doubling our earlier data. These lifetimes are consistent with our published results and the two data samples have been combined. From the resulting 42 neutral, 45 charged and 13 topologically ambiguous decays the charmed meson lifetimes are measured to be tau/sub D/sup 0// = (6.4/sub -0.9//sup +1.1/ +- 0.5) x 10/sup -13/s and tau/sub D/sup + -// = (8.2/sub -1.1//sup +1.3/ +- 0.6) x 10/sup -13/s and their ratio tau/sub D//sup + -///tau/sub D/sup 0// = 1.3/sub -0.3/sup +0.5/. The inclusive charm cross-section at a photon energy of 20 GeV has been measured to be 60 +- 8 +- 21) nb.

  4. Solid-like and liquid-like behaviour in small benzene clusters. A molecular dynamics simulation of (C 6H 6) 4

    NASA Astrophysics Data System (ADS)

    Del Mistro, G.; Stace, A. J.

    1990-08-01

    Molecular dynamics simulations have been performed on the cluster (C 6H 6) 4 with the individual molecules being treated as rigid rotors. Behaviour characteristic of melting is observed at internal temperatures as low as 80 K. It is concluded that the clusters begin to exhibit liquid-like properties when individual molecules acquire sufficient kinetic energy to execute large-ampli- tude motion.

  5. Modulation of Closed-State Inactivation in Kv2.1/Kv6.4 Heterotetramers as Mechanism for 4-AP Induced Potentiation.

    PubMed

    Stas, Jeroen I; Bocksteins, Elke; Labro, Alain J; Snyders, Dirk J

    2015-01-01

    The voltage-gated K+ (Kv) channel subunits Kv2.1 and Kv2.2 are expressed in almost every tissue. The diversity of Kv2 current is increased by interacting with the electrically silent Kv (KvS) subunits Kv5-Kv6 and Kv8-Kv9, into functional heterotetrameric Kv2/KvS channels. These Kv2/KvS channels possess unique biophysical properties and display a more tissue-specific expression pattern, making them more desirable pharmacological and therapeutic targets. However, little is known about the pharmacological properties of these heterotetrameric complexes. We demonstrate that Kv5.1, Kv8.1 and Kv9.3 currents were inhibited differently by the channel blocker 4-aminopyridine (4-AP) compared to Kv2.1 homotetramers. In contrast, Kv6.4 currents were potentiated by 4-AP while displaying moderately increased affinities for the channel pore blockers quinidine and flecainide. We found that the 4-AP induced potentiation of Kv6.4 currents was caused by modulation of the Kv6.4-mediated closed-state inactivation: suppression by 4-AP of the Kv2.1/Kv6.4 closed-state inactivation recovered a population of Kv2.1/Kv6.4 channels that was inactivated at resting conditions, i.e. at a holding potential of -80 mV. This modulation also resulted in a slower initiation and faster recovery from closed-state inactivation. Using chimeric substitutions between Kv6.4 and Kv9.3 subunits, we demonstrated that the lower half of the S6 domain (S6c) plays a crucial role in the 4-AP induced potentiation. These results demonstrate that KvS subunits modify the pharmacological response of Kv2 subunits when assembled in heterotetramers and illustrate the potential of KvS subunits to provide unique pharmacological properties to the heterotetramers, as is the case for 4-AP on Kv2.1/Kv6.4 channels.

  6. Seasonal and spatial variabilities in the water chemistry of prairie pothole wetlands influence the photoproduction of reactive intermediates.

    PubMed

    McCabe, Andrew J; Arnold, William A

    2016-07-01

    The hydrology and water chemistry of prairie pothole wetlands vary spatially and temporally, on annual and decadal timescales. Pesticide contamination of wetlands arising from agricultural activities is a foremost concern. Photochemical reactions are important in the natural attenuation of pesticides and may be important in limiting ecological and human exposure. Little is known, however, about the variable influence of wetland water chemistry on indirect photochemistry. In this study, seasonal water samples were collected from seven sites throughout the prairie pothole region over three years to understand the spatiotemporal dynamics of reactive intermediate photoproduction. Samples were classified by the season in which they were collected (spring, summer, or fall) and the typical hydroperiod of the wetland surface water (temporary or semi-permanent). Under photostable conditions, steady-state concentrations and apparent quantum yields or quantum yield coefficients were measured for triplet excited states of dissolved organic matter, singlet oxygen, hydroxyl radical, and carbonate radical under simulated sunlight. Steady-state concentrations and quantum yields increased on average by 15% and 40% from spring to fall, respectively. Temporary wetlands had 40% higher steady-state concentrations of reactive intermediates than semi-permanent wetlands, but 50% lower quantum yields. Computed quantum yields for reactive intermediate formation were used to predict the indirect photochemical half-lives of seven pesticides in average temporary and semi-permanent prairie pothole wetlands. As a first approximation, the predictions agree to within two orders of magnitude of previously reported half-lives.

  7. Polarization components in π0 photoproduction at photon energies up to 5.6 GeV

    SciTech Connect

    Luo, W.; Brash, E. J.; Gilman, R.; Jones, M. K.; Meziane, M.; Pentchev, L.; Perdrisat, C. F; Puckett, A. J.R.; Punjabi, V.; Wesselmann, F. R.; Marsh, A.; Matulenko, Y.; Maxwell, J.; Meekins, D.; Melnik, Y.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Moffit, B.; Moreno, O.; Mulholland, J.; Narayan, A.; Nuruzzaman, .; Nedev, S.; Piasetzky, E.; Pierce, W.; Piskunov, N. M.; Prok, Y.; Ransome, R. D.; Razin, D. S.; Reimer, P. E.; Reinhold, J.; Rondon, O.; Shabestari, M.; Shahinyan, A.; Shestermanov, K.; Sirca, S.; Sitnik, I.; Smykov, L.; Smith, G.; Solovyev, L.; Solvignon, P.; Strakovsky, I. I; Subedi, R.; Suleiman, R.; Tomasi-Gustafsson, E.; Vasiliev, A.; Veilleux, M.; Wood, S.; Ye, Z.; Zanevsky, Y.; Zhang, X.; Zhang, Y.; Zheng, X.; Zhu, L.; Ahmidouch, A.; Albayrak, I.; Aniol, K. A.; Arrington, J.; Asaturyan, A.; Ates, O.; Baghdasaryan, H.; Benmokhtar, F.; Bertozzi, W.; Bimbot, L.; Bosted, P.; Boeglin, W.; Butuceanu, C.; Carter, P.; Chernenko, S.; Christy, M. E.; Commisso, M.; Cornejo, J. C.; Covrig, S.; Danagoulian, S.; Daniel, A.; Davidenko, A.; Day, D.; Dhamija, S.; Dutta, D.; Ent, R.; Frullani, S.; Fenker, H.; Frlez, E.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Goncharenko, Y.; Hafidi, K.; Hamilton, D.; Higinbotham, D. W.; Hinton, W.; Horn, T.; Hu, B.; Huang, J.; Huber, G. M.; Jensen, E.; Kang, H.; Keppel, C.; Khandaker, M.; King, P.; Kirillov, D.; Kohl, M.; Kravtsov, V.; Kumbartzki, G.; Li, Y.; Mamyan, V.; Margaziotis, D. J.; Markowitz, P.

    2012-05-31

    We present new data for the polarization observables of the final state proton in the 1H(→ γ, → p)π0 reaction. These data can be used to test predictions based on hadron helicity conservation (HHC) and perturbative QCD (pQCD). These data have both small statistical and systematic uncertainties, and were obtained with beam energies between 1.8 and 5.6 GeV and for π0 scattering angles larger than 75{sup o} in center-of-mass (c.m.) frame. The data extend the polarization measurements data base for neutral pion photoproduction up to Eγ = 5.6 GeV. The results show non-zero induced polarization above the resonance region. The polarization transfer components vary rapidly with the photon energy and π0 scattering angle in the center-of-mass frame. This indicates that HHC does not hold and that the pQCD limit is still not reached in the energy regime of this experiment.

  8. Polarization components in π0 photoproduction at photon energies up to 5.6 GeV

    DOE PAGES

    Luo, W.; Brash, E. J.; Gilman, R.; ...

    2012-05-31

    We present new data for the polarization observables of the final state proton in the 1H(→ γ, → p)π0 reaction. These data can be used to test predictions based on hadron helicity conservation (HHC) and perturbative QCD (pQCD). These data have both small statistical and systematic uncertainties, and were obtained with beam energies between 1.8 and 5.6 GeV and for π0 scattering angles larger than 75{sup o} in center-of-mass (c.m.) frame. The data extend the polarization measurements data base for neutral pion photoproduction up to Eγ = 5.6 GeV. The results show non-zero induced polarization above the resonance region. Themore » polarization transfer components vary rapidly with the photon energy and π0 scattering angle in the center-of-mass frame. This indicates that HHC does not hold and that the pQCD limit is still not reached in the energy regime of this experiment.« less

  9. Photoproduction of lepton pairs in proton-nucleus and nucleus-nucleus collisions at RHIC and LHC energies

    SciTech Connect

    Moreira, B. D.; Goncalves, V. P.; De Santana Amaral, J. T.

    2013-03-25

    In this contribution we study coherent interactions as a probe of the nonlinear effects in the Quantum Electrodynamics (QED). In particular, we study the multiphoton effects in the production of leptons pairs for proton-nucleus and nucleus-nucleus collisions for heavy nuclei. In the proton-nucleus we assume the ultrarelativistic proton as a source of photons and estimate the photoproduction of lepton pairs on nuclei at RHIC and LHC energies considering the multiphoton effects associated to multiple rescattering of the projectile photon on the proton of the nucleus. In nucleus - nucleus colllisions we consider the two nuclei as a source of photons. As each scattering contributes with a factor {alpha}Z to the cross section, this contribution must be taken into account for heavy nuclei. We consider the Coulomb corrections to calculate themultiple scatterings and estimate the total cross section for muon and tau pair production in proton-nucleus and nucleus-nucleus collisions at RHIC and LHC energies.

  10. Rapidity and momentum transfer distributions of coherent J/ψ photoproduction in ultraperipheral pPb collisions at the LHC

    NASA Astrophysics Data System (ADS)

    Guzey, V.; Zhalov, M.

    2014-02-01

    Based on accurate calculations of the flux of equivalent photons of the proton and heavy nuclei and the pQCD framework for the gluon distribution in the proton and nuclei, we analyze the rapidity and momentum transfer distributions of coherent J/ψ photoproduction in ultraperipheral proton-Pb collisions at the LHC. We demonstrate that unlike the case of proton-proton UPCs marred by certain theoretical uncertainties and experimental limitations, after a cut excluding the region of small momentum transfers, ultraperipheral proton-Pb collisions offer a clean way to study the gluon distribution in the proton down to x ≈ 10-5. Our analysis of the momentum transfer distributions shows that an interplay of J/ψ production by low-energy photons on the nucleus and by high-energy photons on the proton in proton-Pb UPCs can result in some excess of events at small p t in a definite region of the rapidity y.

  11. Two-Photon Absorption of Bacteriorhodopsin: Formation of a Red-Shifted Thermally Stable Photoproduct F620

    PubMed Central

    Fischer, Thorsten; Hampp, Norbert A.

    2005-01-01

    By means of high-intensity 532 nm laser pulses, a photochemical conversion of the initial B570 state of bacteriorhodopsin (BR) to a stable photoproduct absorbing maximally at ≈620 nm in BR suspensions and at ≈610 nm in BR films is induced. This state, which we named F620, is photochemically further converted to a group of three products with maximal absorptions in the wavelength range from 340 nm to 380 nm, which show identical spectral properties to the so-called P360 state reported in the literature. The photoconversion from B570 to F620 is most likely a resonant two-photon absorption induced step. The formation of F620 and P360 leads to a distinguished photo-induced permanent optical anisotropy in BR films. The spectral dependence of the photo-induced anisotropy and the anisotropy orientations at the educt (B570) and product (F620) wavelengths are strong indicators that F620 is formed in a direct photochemical step from B570. The chemical nature of the P360 products probably is that of a retro-retinal containing BR, but the structural characteristics of the F620 state are still unclear. The photo-induced permanent anisotropy induced by short laser pulses in BR films helps to better understand the photochemical pathways related to this transition, and it is interesting in view of potential applications as this feature is the molecular basis for permanent optical data storage using BR films. PMID:15894635

  12. Coherent π{sup 0}-photoproduction on the deuteron near the η-production threshold including polarization observables

    SciTech Connect

    Darwish, Eed M.; Al-Thoyaib, Suleiman S.

    2014-12-15

    Coherent π{sup 0}-photoproduction on the deuteron including polarization observables is studied in the energy region near the η-production threshold at backward center-of-mass angles of the outgoing pion. This work is motivated by the measurements of the CLAS Collaboration at Jefferson Lab, where a cusp-like structure in the energy dependence of the differential cross section has been observed at extremely backward pion angles. The present approach is based on the impulse approximation and first-order rescattering diagrams with intermediate production of both π- and η-mesons. Numerical results for unpolarized cross sections, the linear photon asymmetry (Σ), the vector (T{sub 11}) and tensor (T{sub 2M}, M=0, 1, 2) deuteron target asymmetries, and the double polarization E-asymmetry are predicted and compared with available experimental data and other theoretical models. The effect of first-order rescattering is found to be much larger in spin asymmetries than in the unpolarized cross sections. It reaches on average about 40% in the tensor target and E asymmetries. Compared to the experimental data from CLAS Collaboration, sizable discrepancies are found. This is not the case for the linear photon asymmetry, for which a better comparison with the data from YerPhI Collaboration is obtained.

  13. In situ photoproduction of dichlorodibenzo- p-dioxin from non-ionic triclosan isolated in solid argon

    NASA Astrophysics Data System (ADS)

    Kuş, Nihal; Reva, Igor; Bayarı, Sevgi; Fausto, Rui

    2012-01-01

    The infrared spectrum of triclosan [or 5-chloro-2-(2,4-dichlorophenoxy)phenol] isolated in a low temperature (˜15 K) argon matrix has been recorded and assigned with help of DFT claculations undertaken with the B3LYP functional and the 6-311++G(d,p) basis set. The obtained spectrum doubtlessly exhibits the characteristic vibrational signature of the neutral (phenol) form of the compound, which exists in two different conformations (forms I and II) in the matrix, in a I: II population ratio of ca. 0.75. Upon broadband UV irradiation of the matrix-isolated triclosan with unfiltered light provided by a xenon arc lamp, formation of 2,8-dichlorodibenzo- p-dioxin (2,8-DCDD) was observed, together with HCl. The reaction seems to occur through initial photoproduction of the triclosan phenol radical derivative, and involve in the initial step participation of dissociative (πσ ∗) excited states along the OH stretching coordinate, as observed previously for other phenol derivatives. The photochemically detached hydrogen atom derived from triclosan may then react with the closest located chlorine atom in the triclosan molecule to yield HCl and a biradical species, which can subsequently undergo a ring-closure reaction by intramolecular recombination, leading to the observed 2,8-DCDD.

  14. The SAURON project - XX. The Spitzer [3.6] - [4.5] colour in early-type galaxies: colours, colour gradients and inverted scaling relations

    NASA Astrophysics Data System (ADS)

    Peletier, Reynier F.; Kutdemir, Elif; van der Wolk, Guido; Falcón-Barroso, Jesús; Bacon, Roland; Bureau, Martin; Cappellari, Michele; Davies, Roger L.; de Zeeuw, P. Tim; Emsellem, Eric; Krajnović, Davor; Kuntschner, Harald; McDermid, Richard M.; Sarzi, Marc; Scott, Nicholas; Shapiro, Kristen L.; van den Bosch, Remco C. E.; van de Ven, Glenn

    2012-01-01

    We investigate the [3.6]-[4.5] Spitzer-IRAC colour behaviour of the early-type galaxies of the SAURON survey, a representative sample of 48 nearby ellipticals and lenticulars. We investigate how this colour, which is unaffected by dust extinction, can be used to constrain the stellar populations in these galaxies. We find a tight relation between the [3.6]-[4.5] colour and effective velocity dispersion, a good mass indicator in early-type galaxies: ([3.6]-[4.5])e = (-0.109 ? 0.007)?+ (0.154 ? 0.016). Contrary to other colours in the optical and near-infrared, we find that the colours become bluer for larger galaxies. The relations are tighter when using the colour inside re (scatter 0.013 mag), rather than the much smaller re/8 aperture (scatter 0.023 mag), due to the presence of young populations in the central regions. We also obtain strong correlations between the [3.6]-[4.5] colour and three strong absorption lines (H?, Mgb and Fe 5015). Comparing our data with the models of Marigo et al., which show that more metal rich galaxies are bluer, we can explain our results in a way consistent with results from the optical, by stating that larger galaxies are more metal rich. The blueing is caused by a strong CO absorption band, whose line strength increases strongly with decreasing temperature and which covers a considerable fraction of the 4.5-?m filter. In galaxies that contain a compact radio source, the [3.6]-[4.5] colour is generally slightly redder (by 0.015 ? 0.007 mag using the re/8 aperture) than in the other galaxies, indicating small amounts of either hot dust, non-thermal emission, or young stars near the centre. We find that the large majority of the galaxies show redder colours with increasing radius. Removing the regions with evidence for young stellar populations (from the H? absorption line) and interpreting the colour gradients as metallicity gradients, we find that our galaxies are more metal poor going outwards. The radial [3.6]-[4.5] gradients

  15. Vulgarisin A, a new diterpenoid with a rare 5/6/4/5 ring skeleton from the Chinese medicinal plant Prunella vulgaris.

    PubMed

    Lou, Huayong; Zheng, Shan; Li, Tianlei; Zhang, Jianxin; Fei, Yue; Hao, Xiaojiang; Liang, Guangyi; Pan, Weidong

    2014-05-16

    Vulgarisin A (1), a new diterpenoid with an unprecedented 5/6/4/5 fused tetracyclic ring skeleton, has been isolated from the medicinal plant Prunella vulgaris Linn. Its structure was characterized by extensive spectroscopic methods, and the absolute configuration was secured by single crystal X-ray diffraction analysis. Compound 1 showed weak cytotoxicity against human lung carcinoma A549 cells with an IC50 value of 57.0 μM.

  16. Enhancement of the catalytic activity of ferulic acid decarboxylase from Enterobacter sp. Px6-4 through random and site-directed mutagenesis.

    PubMed

    Lee, Hyunji; Park, Jiyoung; Jung, Chaewon; Han, Dongfei; Seo, Jiyoung; Ahn, Joong-Hoon; Chong, Youhoon; Hur, Hor-Gil

    2015-11-01

    The enzyme ferulic acid decarboxylase (FADase) from Enterobacter sp. Px6-4 catalyzes the decarboxylation reaction of lignin monomers and phenolic compounds such as p-coumaric acid, caffeic acid, and ferulic acid into their corresponding 4-vinyl derivatives, that is, 4-vinylphenol, 4-vinylcatechol, and 4-vinylguaiacol, respectively. Among various ferulic acid decarboxylase enzymes, we chose the FADase from Enterobacter sp. Px6-4, whose crystal structure is known, and produced mutants to enhance its catalytic activity by random and site-directed mutagenesis. After three rounds of sequential mutations, FADase(F95L/D112N/V151I) showed approximately 34-fold higher catalytic activity than wild-type for the production of 4-vinylguaiacol from ferulic acid. Docking analyses suggested that the increased activity of FADase(F95L/D112N/V151I) could be due to formation of compact active site compared with that of the wild-type FADase. Considering the amount of phenolic compounds such as lignin monomers in the biomass components, successfully bioengineered FADase(F95L/D112N/V151I) from Enterobacter sp. Px6-4 could provide an ecofriendly biocatalytic tool for producing diverse styrene derivatives from biomass.

  17. Carotenoid Biosynthesis in Calothrix sp. 336/3: Composition of Carotenoids on Full Medium, During Diazotrophic Growth and After Long-Term H2 Photoproduction.

    PubMed

    Kosourov, Sergey; Murukesan, Gayathri; Jokela, Jouni; Allahverdiyeva, Yagut

    2016-11-01

    The carotenoid composition of the filamentous heterocystous N2-fixing cyanobacterium Calothrix sp. 336/3 was investigated under three conditions: in full medium (non-diazotrophic growth); in the absence of combined nitrogen (diazotrophic growth); and after long-term H2 photoproduction (diazotrophic medium and absence of nitrogen in the atmosphere). Anabaena sp. PCC 7120 and its ΔhupL mutant with disrupted uptake hydrogenase were used as reference strains. Analysis of identified carotenoids and enzymes involved in carotenogenesis showed the presence of three distinct biosynthetic pathways in Calothrix sp. 336/3. The first one is directed towards biosynthesis of myxoxanthophylls, such as myxol 2'-methylpentoside and 2-hydroxymyxol 2'-methylpentoside. The second pathway results in production of hydroxylated carotenoids, such as zeaxanthin, caloxanthin and nostoxanthin, and the last pathway is responsible for biosynthesis of echinenone and hydroxylated forms of ketocarotenoids, such as 3'-hydroxyechinenone and adonixanthin. We found that carotenogenesis in filamentous heterocystous cyanobacteria varies depending on the nitrogen status of the cultures, with significant accumulation of echinenone during diazotrophic growth at the expense of β-carotene. Under the severe N deficiency and high CO2 supply, which leads to efficient H2 photoproduction, cyanobacteria degrade echinenone and β-carotene, and accumulate glycosylated and hydroxylated carotenoids, such as myxol (or ketomyxol) 2'-methylpentosides, 3'-hydroxyechinenone and zeaxanthin. We suggest that the stability of the photosynthetic apparatus in Calothrix sp. 336/3 cells under N deficiency and high carbon conditions, which also appeared as the partial recovery of the pigment composition by the end of the long-term (∼1 month) H2 photoproduction process, might be mediated by a high content of hydroxycarotenoids.

  18. Inclusive photoproduction of bottom quarks for low and medium pT in the general-mass variable-flavour-number scheme

    NASA Astrophysics Data System (ADS)

    Kramer, G.; Spiesberger, H.

    2016-02-01

    We present predictions for b-quark production in photoproduction and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e+e- data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.

  19. Rapid deamination of cyclobutane pyrimidine dimer photoproducts at TCG sites in a translationally and rotationally positioned nucleosome in vivo.

    PubMed

    Cannistraro, Vincent J; Pondugula, Santhi; Song, Qian; Taylor, John-Stephen

    2015-10-30

    Sunlight-induced C to T mutation hot spots in skin cancers occur primarily at methylated CpG sites that coincide with sites of UV-induced cyclobutane pyrimidine dimer (CPD) formation. The C and 5-methyl-C in CPDs are not stable and deaminate to U and T, respectively, which leads to the insertion of A by the DNA damage bypass polymerase η, thereby defining a probable mechanism for the origin of UV-induced C to T mutations. Deamination rates for T(m)CG CPDs have been found to vary 12-fold with rotational position in a nucleosome in vitro. To determine the influence of nucleosome structure on deamination rates in vivo, we determined the deamination rates of CPDs at TCG sites in a stably positioned nucleosome within the FOS promoter in HeLa cells. A procedure for in vivo hydroxyl radical footprinting with Fe-EDTA was developed, and, together with results from a cytosine methylation protection assay, we determined the translational and rotational positions of the TCG sites. Consistent with the in vitro observations, deamination was slower for one CPD located at an intermediate rotational position compared with two other sites located at outside positions, and all were much faster than for CPDs at non-TCG sites. Photoproduct formation was also highly suppressed at one site, possibly due to its interaction with a histone tail. Thus, it was shown that CPDs of TCG sites deaminate the fastest in vivo and that nucleosomes can modulate both their formation and deamination, which could contribute to the UV mutation hot spots and cold spots.

  20. Hydrogen Photoproduction by Nutrient-Deprived Chalamydomonas reinhardtii Cells Immobilized Within Thin Alginate Films Under Aerobic and Anaerobic Conditions

    SciTech Connect

    Kosourov, S. N.; Seibert, M.

    2009-01-01

    A new technique for immobilizing H{sub 2}-photoproducing green algae within a thin (<400 {micro}m) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus-deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 {micro}g Chl mL{sup -1} of matrix), (b) kinetics of H{sub 2} photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 {micro}mol mg{sup -1} Chl h{sup -1}) of H{sub 2} evolution, (d) light conversion efficiencies to H{sub 2} of over 1% and (e) unexpectedly high resistance of the H{sub 2}-photoproducing system to inactivation by atmospheric O{sub 2}. The algal cells, entrapped in alginate and then placed in vials containing 21% O{sub 2} in the headspace, evolved up to 67% of the H{sub 2} gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H{sub 2}-producing system to inactivation by O{sub 2} depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O{sub 2} in the liquid and headspace and restrict O{sub 2} diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale-up and possible future applications.

  1. Evidence for proximal control of ligand specificity in hemeproteins: Absorption and Raman studies of cryogenically trapped photoproducts of ligand bound myoglobins

    NASA Astrophysics Data System (ADS)

    Ahmed, A. M.; Campbell, B. F.; Caruso, D.; Chance, M. R.; Chavez, M. D.; Courtney, S. H.; Friedman, J. M.; Iben, I. E. T.; Ondrias, M. R.; Yang, M.

    1991-12-01

    The absorption and resonance Raman spectra of cryogenically trapped photoproducts of oxy and carboxy derivatives of myoglobin (Mb) are compared and analyzed in an attempt to understand the structural basis for ligand specificity in hemeproteins. Pulsed and cw excitations over a wide temperature range are used in order to differentiate between kinetic hole burning (KHB), optical pumping of structural relaxation, and spontaneous relaxation effects. Using these techniques, we are able to correlate changes in the absorption spectrum (band III at ≈ 760 nm) with low-frequency Raman bands. Based on these correlations we are able to determine which proximal heme pocket parameters are participating in KHB and optical pumping phenomena. Differences in the spectra of the ligand specific photoproducts have revealed differences in the populations of conformational substates (CS) that participate in the geminate recombination (process I) at cryogenic temperatures. A model is presented that relates the ligand specific spectral differences to structural and functional differences in the bound protein. What emerges is evidence that Mb and hemoglobin (Hb) can differentiate between O 2 and CO based on proximal control of the bond forming step between the ligand and the iron.

  2. Unexpected photoproduct generated via the acetone-sensitized photolysis of 5-bromo-2'-deoxyuridine in a water/isopropanol solution: experimental and computational studies.

    PubMed

    Polska, Katarzyna; Zielonka, Justyna; Chomicz, Lidia; Czerwicka, Małgorzata; Stepnowski, Piotr; Guzow, Katarzyna; Wiczk, Wiesław; Smużyńska, Maria; Kasprzykowski, Franciszek; Żylicz-Stachula, Agnieszka; Skowron, Piotr; Rak, Janusz

    2010-12-23

    The acetone-sensitized photolysis of 5-bromo-2'-deoxyuridine (5-BrdU) in a water/isopropanol solution with 300 nm photons leads to the formation of 2'-deoxyuridine (dU) and a comparable amount of another photoproduct that has not been reported in the literature so far. The negative and positive mass spectra recorded for this species indicate that they originate from the molecular mass of 286 Da, which corresponds to an adduct of 2'-deoxyuridine and 2-propanol. Quantum chemical calculations carried out at the DFT and TDDFT levels reveal both the structure and the UV spectrum of that adduct. The latter computational characteristic matches well the experimental UV spectrum of the new photoproduct. Our findings indicate that the acetone-sensitized photolysis of 5-BrdU is more complicated than has hitherto been assumed. Nevertheless, since electron transfer is one of the pathways responsible for 5-BrdU decay, acetone-sensitized photolysis of the halogen derivatives of nucleobases could be a convenient tool for studying their radiosensitivity in aqueous solutions.

  3. Observation of pi+pi-pi+pi- photoproduction in ultraperipheral heavy-ion collisions at sqrt sNN = 200 GeV at the STAR detector

    SciTech Connect

    STAR Collaboration; Abelev, Betty

    2010-07-05

    We present a measurement of {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} photonuclear production in ultra-peripheral Au-Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540 {+-} 40 MeV/c{sup 2} with a width of 570 {+-} 60 MeV/c{sup 2}, in agreement with the photoproduction data for the {rho}{sup 0}(1700). We do not observe a corresponding peak in the {pi}{sup +}{pi}{sup -} final state and measure an upper limit for the ratio of the branching fractions of the {rho}{sup 0}(1700) to {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} of 2.5% at 90% confidence level. The ratio of {rho}{sup 0}(1700) and {rho}{sup 0}(770) coherent production cross sections is measured to be 13.4 {+-} 0.8{sub stat.} {+-} 4.4{sub syst.}%.

  4. Identification of halogenated photoproducts generated after ultraviolet-irradiation of parabens and benzoates in water containing chlorine by solid-phase microextraction and gas chromatography-mass spectrometry.

    PubMed

    Alvarez-Rivera, Gerardo; Llompart, Maria; Garcia-Jares, Carmen; Lores, Marta

    2014-07-04

    This work presents a new solid-phase microextraction (SPME)-based approach to investigate the formation of halogenated by-products generated by the UV-induced photodegradation of parabens and their congener benzoates in water containing chlorine. Degradation of parent species, and further identification of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC/MS). In order to improve detectability, SPME was applied as a preconcentration step after UV-irradiation of target preservatives. Experiments performed with dechlorinated water, ultrapure water, and tap water showed that under UV-light, the presence of even low levels of free chlorine, increases the photodegradation rate of target preservatives, enhancing the formation of halogenated photoproducts. Monobrominated, dibrominated and bromochlorinated hydroxybenzoates were identified, and the transformation of benzoates into halogenated parabens was also confirmed. Bromination is expected to occur when free chlorine is present, due to the presence of traces of bromide in water samples. Five halogenated phenols (mainly brominated) were detected as breakdown photoproducts from both families of target preservatives. On the basis of the appearance of the aforementioned by-products, a tentative transformation pathway, consistent with the photoformation-photodecay kinetics of the by-products, is proposed herein for the first time.

  5. Exclusive J /ψ Photoproduction off Protons in Ultraperipheral p -Pb Collisions at √{sNN }=5.02 TeV

    NASA Astrophysics Data System (ADS)

    Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Baumann, C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Belmont, R.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Berger, M. E.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Böhmer, F. V.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Casula, E. A. R.; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, D.; Das, I.; Das, K.; Das, S.; Dash, A.; Dash, S.; de, S.; Delagrange, H.; Deloff, A.; Dénes, E.; D'Erasmo, G.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; de Rooij, R.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; di Bari, D.; di Liberto, S.; di Mauro, A.; di Nezza, P.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dørheim, S.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Hilden, T. E.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Eschweiler, D.; Espagnon, B.; Esposito, M.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gumbo, M.; Gunji, T.; Gupta, A.; Gupta, R.; Khan, K. H.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hippolyte, B.; Hladky, J.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Innocenti, G. M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kadyshevskiy, V.; Kalcher, S.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil Svn, M.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; La Pointe, S. L.; La Rocca, P.; Lea, R.; Leardini, L.; Lee, G. R.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Leoncino, M.; León Monzón, I.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Lopez, X.; López Torres, E.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Ma, R.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martin Blanco, J.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mlynarz, J.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Okatan, A.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Sahoo, P.; Pachmayer, Y.; Pachr, M.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palmeri, A.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira da Costa, H.; Pereira de Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Pesci, A.; Peskov, V.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Pohjoisaho, E. H. O.; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Rauf, A. W.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohni, S.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, R.; Sahu, P. K.; Saini, J.; Sakai, S.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sánchez Rodríguez, F. J.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Segato, G.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Shangaraev, A.; Sharma, N.; Sharma, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wagner, V.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yang, S.; Yano, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I.-K.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zaman, A.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, F.; Zhou, Y.; Zhou, Zhuo; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zoccarato, Y.; Zyzak, M.; Alice Collaboration

    2014-12-01

    We present the first measurement at the LHC of exclusive J /ψ photoproduction off protons, in ultraperipheral proton-lead collisions at √{sNN }=5.02 TeV . Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5 photoproduction cross section in γ p energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ˜2 ×10-2 and ˜2 ×10-5, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.

  6. Exclusive J/ψ photoproduction off protons in ultraperipheral p-Pb collisions at √(s(NN))=5.02 TeV.

    PubMed

    Abelev, B; Adam, J; Adamová, D; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agostinelli, A; Agrawal, N; Ahammed, Z; Ahmad, N; Ahmed, I; Ahn, S U; Ahn, S A; Aimo, I; Aiola, S; Ajaz, M; Akindinov, A; Alam, S N; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arcelli, S; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Augustinus, A; Averbeck, R; Awes, T C; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batista Camejo, A; Batyunya, B; Batzing, P C; Baumann, C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Belmont, R; Belyaev, V; Bencedi, G; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Berger, M E; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhat, I R; Bhati, A K; Bhattacharjee, B; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Bjelogrlic, S; Blanco, F; Blau, D; Blume, C; Bock, F; Bogdanov, A; Bøggild, H; Bogolyubsky, M; Böhmer, F V; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Bossú, F; Botje, M; Botta, E; Böttger, S; Braun-Munzinger, P; Bregant, M; Breitner, T; Broker, T A; Browning, T A; Broz, M; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Caffarri, D; Cai, X; Caines, H; Calero Diaz, L; Caliva, A; Calvo Villar, E; Camerini, P; Carena, F; Carena, W; Castillo Castellanos, J; Casula, E A R; Catanescu, V; Cavicchioli, C; Ceballos Sanchez, C; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Chelnokov, V; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Colocci, M; Conesa Balbastre, G; Conesa Del Valle, Z; Connors, M E; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortés Maldonado, I; Cosentino, M R; Costa, F; Crochet, P; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Dainese, A; Dang, R; Danu, A; Das, D; Das, I; Das, K; Das, S; Dash, A; Dash, S; De, S; Delagrange, H; Deloff, A; Dénes, E; D'Erasmo, G; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; de Rooij, R; Diaz Corchero, M A; Dietel, T; Dillenseger, P; Divià, R; Di Bari, D; Di Liberto, S; Di Mauro, A; Di Nezza, P; Djuvsland, Ø; Dobrin, A; Dobrowolski, T; Domenicis Gimenez, D; Dönigus, B; Dordic, O; Dørheim, S; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; Hilden, T E; Ehlers, R J; Elia, D; Engel, H; Erazmus, B; Erdal, H A; Eschweiler, D; Espagnon, B; Esposito, M; Estienne, M; Esumi, S; Evans, D; Evdokimov, S; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Feofilov, G; Ferencei, J; Fernández Téllez, A; Ferreiro, E G; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Furs, A; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A M; Gallio, M; Gangadharan, D R; Ganoti, P; Gao, C; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Garishvili, I; Gerhard, J; Germain, M; Gheata, A; Gheata, M; Ghidini, B; Ghosh, P; Ghosh, S K; Gianotti, P; Giubellino, P; Gladysz-Dziadus, E; Glässel, P; Gomez Ramirez, A; González-Zamora, P; Gorbunov, S; Görlich, L; Gotovac, S; Graczykowski, L K; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gumbo, M; Gunji, T; Gupta, A; Gupta, R; Khan, K H; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hanratty, L D; Hansen, A; Harris, J W; Hartmann, H; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Hess, B A; Hetland, K F; Hippolyte, B; Hladky, J; Hristov, P; Huang, M; Humanic, T J; Hussain, N; Hutter, D; Hwang, D S; Ilkaev, R; Ilkiv, I; Inaba, M; Innocenti, G M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, M; Ivanov, V; Jachołkowski, A; Jacobs, P M; Jahnke, C; Jang, H J; Janik, M A

    2014-12-05

    We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sqrt[s_{NN}]=5.02  TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2×10^{-2} and ∼2×10^{-5}, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.

  7. Observation of pi+ pi- pi+pi- photoproduction in ultraperipheral heavy-ion collisons at sqrt sNN = 200 GeV at the STAR Detector

    SciTech Connect

    Abelev, B.I.; Dunlop, J.; et al. STAR Collaboration

    2010-04-02

    We present a measurement of {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} photonuclear production in ultraperipheral Au-Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540 {+-} 40 MeV/c{sup 2} with a width of 570 {+-} 60 MeV/c{sup 2}, in agreement with the photoproduction data for the {rho}{sup 0}(1700). We do not observe a corresponding peak in the {pi}{sup +}{pi}{sup -} final state and measure an upper limit for the ratio of the branching fractions of the {rho}{sup 0}(1700) to {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} of 2.5% at 90% confidence level. The ratio of {rho}{sup 0}(1700) and {rho}{sup 0}(770) coherent production cross sections is measured to be 13.4 {+-} 0.8{sub stat.}{+-}4.4{sub syst.}%.

  8. Synthesis of N-(6-(4-(Piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide Derivatives for the Treatment of Metabolic Syndrome

    PubMed Central

    Bajare, Swapnil; Anthony, Jessy; Nair, Amrutha; Damre, Anagha; B-Rao, Chandrika; Sivaramakrishnan, H.; Wilankar, Chandan; Marita, Rosalind

    2013-01-01

    Metabolic syndrome is a widely prevalent multifactorial disorder associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. High plasma levels of insulin and glucose due to insulin resistance are a major component of the metabolic disorder. Thiazolidinediones (TZDs) are potent PPARγ ligand and used as insulin sensitizers in the treatment of type 2 diabetes mellitus. They are potent insulin-sensitizing agents but due to adverse effects like hepatotoxicity, a safer alternative of TZDs is highly demanded. Here we report synthesis of N-(6-(4-(piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide derivatives as an alternate remedy for insulin resistance. PMID:25374688

  9. PPL2 Translesion Polymerase Is Essential for the Completion of Chromosomal DNA Replication in the African Trypanosome

    PubMed Central

    Rudd, Sean G.; Glover, Lucy; Jozwiakowski, Stanislaw K.; Horn, David; Doherty, Aidan J.

    2013-01-01

    Summary Faithful copying of the genome is essential for life. In eukaryotes, a single archaeo-eukaryotic primase (AEP), DNA primase, is required for the initiation and progression of DNA replication. Here we have identified additional eukaryotic AEP-like proteins with DNA-dependent primase and/or polymerase activity. Uniquely, the genomes of trypanosomatids, a group of kinetoplastid protozoa of significant medical importance, encode two PrimPol-like (PPL) proteins. In the African trypanosome, PPL2 is a nuclear enzyme present in G2 phase cells. Following PPL2 knockdown, a cell-cycle arrest occurs after the bulk of DNA synthesis, the DNA damage response is activated, and cells fail to recover. Consistent with this phenotype, PPL2 replicates damaged DNA templates in vitro, including templates containing the UV-induced pyrimidine-pyrimidone (6-4) photoproduct. Furthermore, PPL2 accumulates at sites of nuclear DNA damage. Taken together, our results indicate an essential role for PPL2 in postreplication tolerance of endogenous DNA damage, thus allowing completion of genome duplication. PMID:24267450

  10. Yeast DNA-repair gene RAD14 encodes a zinc metalloprotein with affinity for ultraviolet-damaged DNA

    SciTech Connect

    Guzder, S.N.; Sung, P.; Prakash, S. ); Prakash, L. )

    1993-06-15

    Xeroderma pigmentosum (XP) patients suffer from a high incidence of skin cancers due to a defect in excision repair of UV light-damaged DNA. Of the seven XP complementation groups, A--G, group A represents a severe and frequent form of the disease. The Saccharomyces cerevisiae RAD14 gene is a homolog of the XP-A correcting (XPAC) gene. Like XP-A cells, rad14-null mutants are defective in the incision step of excision repair of UV-damaged DNA. The authors have purified RAD14 protein to homogeneity from extract of a yeast strain genetically tailored to overexpress RAD14. As determined by atomic emission spectroscopy, RAD14 contains one zinc atom. They also show in vitro that RAD14 binds zinc but does not bind other divalent metal ions. In DNA mobility-shift assays, RAD14 binds specifically to UV-damaged DNA. Removal of cyclobutane pyrimidine dimers from damaged DNA by enzymatic photoreactivation has no effect on binding, strongly suggesting that RAD14 recognizes pyrimidine(6-4)pyrimidone photoproduct sites. These findings indicate that RAD14 functions in damage recognition during excision repair. 37 refs., 4 figs.

  11. Effects of chronic low-dose ultraviolet B radiation on DNA damage and repair in mouse skin.

    PubMed

    Mitchell, D L; Greinert, R; de Gruijl, F R; Guikers, K L; Breitbart, E W; Byrom, M; Gallmeier, M M; Lowery, M G; Volkmer, B

    1999-06-15

    Chronic exposure to sunlight causes skin cancer in humans, yet little is known about how habitual exposure to low doses of ultraviolet B radiation (UVB) affects DNA damage in the skin. We treated Skh-1 hairless mice with daily doses of suberythemal UVB for 40 days and analyzed the amount and distribution of DNA photodamage using RIAs and immunofluorescence micrography. We found that DNA damage accumulated in mouse skin as a result of chronic irradiation and that this damage persisted in the dermis and epidermis for several weeks after the chronic treatment was terminated. Although the persistent damage was evenly distributed throughout the dermis, it remained in the epidermis as a small number of heavily damaged cells at the dermal-epidermal boundary. Rates of DNA damage induction and repair were determined at different times over the course of chronic treatment in response to a higher challenge dose of UVB light. The amount of damage induced by the challenge dose increased in response to chronic exposure, and excision repair of cyclobutane pyrimidine dimers and pyrimidine(6-4)pyrimidone dimers was significantly reduced. The sensitization of mouse epidermal DNA to photoproduct induction, the reduction in excision repair, and the accumulation of nonrepairable DNA damage in the dermis and epidermis suggest that chronic low-dose exposure to sunlight may significantly enhance the predisposition of mammalian skin to sunlight-induced carcinogenesis.

  12. Cyclobutane Pyrimidine Dimer Density as a Predictive Biomarker of the Biological Effects of Ultraviolet Radiation in Normal Human Fibroblast

    PubMed Central

    Sproul, Christopher D.; Mitchell, David L.; Rao, Shangbang; Ibrahim, Joseph G.; Kaufmann, William K.; Cordeiro-Stone, Marila

    2015-01-01

    This study compared biological responses of normal human fibroblasts (NHF1) to three sources of ultraviolet radiation (UVR), emitting UVC wavelengths, UVB wavelengths, or a combination of UVA and UVB (solar simulator; emission spectrum, 94.3% UVA and 5.7% UVB). The endpoints measured were cytotoxicity, intra-S checkpoint activation, inhibition of DNA replication and mutagenicity. Results show that the magnitude of each response to the indicated radiation sources was best predicted by the density of DNA cyclobutane pyrimidine dimers (CPD). The density of 6-4 pyrimidine–pyrimidone photoproducts was highest in DNA from UVC-irradiated cells (14% of CPD) as compared to those exposed to UVB (11%) or UVA–UVB (7%). The solar simulator source, under the experimental conditions described here, did not induce the formation of 8-oxo-7,8-dihydroguanine in NHF1 above background levels. Taken together, these results suggest that CPD play a dominant role in DNA damage responses and highlight the importance of using endogenous biomarkers to compare and report biological effects induced by different sources of UVR. PMID:24148148

  13. CPD photolyase gene from Spinacia oleracea: repair of UV-damaged DNA and expression in plant organs.

    PubMed

    Yoshihara, Ryouhei; Imaki, Toshiyuki; Hori, Manabu; Watanabe, Chihiro; Yamamoto, Kazuo; Takimoto, Koichi

    2005-06-01

    The UV-B radiation contained in solar radiation has deleterious effects on plant growth, development and physiology. Specific damage to DNA caused by UV radiation involves the cyclobutyl pyrimidine dimers (CPD) and the pyrimidine (6-4) pyrimidone photoproducts. CPDs are repaired by CPD photolyase via a UV-A/blue light-dependent mechanism. The gene for the class II CPD photolyase has been cloned from higher plants such as Arabidopsis, cucumbers and rice. We isolated and characterized the cDNA and a genomic clone encoding the spinach class II CPD photolyase. The gene consisted of 3777 bases and 9 exons. The sequence of amino acids predicted from the nucleotide sequence of the cDNA of the gene was highly homologous to that of the higher plants listed above. When a photolyase-deficient Escherichia coli strain was transformed with the cDNA, photoreactivation activity was partially restored, by the illumination with photoreactivating light, resulting in an increased survival and decreased content of CPDs in the Escherichia coli genome. In both the male and female plants, the gene was highly expressed in leaves and flowers under the condition of 14-h light and 10-h dark cycle. The expression in the roots was quite low compared with the other organs.

  14. Origin of anomalous electronic circular dichroism spectrum of RuPt2(tppz)2Cl2(PF6)4 in acetonitrile.

    PubMed

    Yu, Hua-Gen

    2014-07-24

    We report a theoretical study of the structures, energetics, and electronic spectra of the Pt(II)/Ru(II) mixed-metal complex RuPt2(tppz)2Cl2(PF6)4 (tppz = 2,3,5,6-tetra(2-pyridyl)pyrazine) in acetonitrile. The hybrid B3LYP density functional theory and its TDDFT methods were used with a complete basis set (CBS) extrapolation scheme and a conductor polarizable continuum model (C-PCM) for solvation effects. Results showed that the trinuclear complex has four types of stable conformers and/or enantiomers. They are separated by high barriers owing to the repulsive H/H geometrical constraints in tppz. A strong entropy effect was found for the dissociation of RuPt2(tppz)2Cl2(PF6)n in acetonitrile. The UV-visible and emission spectra of the complex were also simulated. They are in good agreement with experiments. In this work we have largely focused on exploring the origin of anomalous electronic circular dichroism (ECD) spectra of the RuPt2(tppz)2Cl2(PF6)4 complex in acetonitrile. As a result, a new mechanism has been proposed together with a clear illustration by using a physical model.

  15. Evaluation of the anticonvulsant activity of 6-(4-chlorophenyoxy)-tetrazolo[5,1-a]phthalazine in various experimental seizure models in mice.

    PubMed

    Sun, Xian-Yu; Wei, Cheng-Xi; Deng, Xian-Qing; Sun, Zhi-Gang; Quan, Zhe-Shan

    2010-01-01

    This study investigated the anticonvulsant activity of a new phthalazine tetrazole derivative, QUAN-0808 (6-(4-chlorophenoxy)-tetrazolo[5,1-a]phthalazine), in the mouse maximal electroshock (MES) seizure model. The neurotoxicity of QUAN-0808 was investigated using the rotarod neurotoxicity test in mice. QUAN-0808 exhibited higher activity (median effective dose, ED(50) = 6.8 mg/kg) and lower neurotoxicity (median toxic dose, TD(50) = 456.4 mg/kg), resulting in a higher protective index (PI = 67.1) compared with carbamazepine (PI = 6.4). In addition, QUAN-0808 exhibited significant oral anticonvulsant activity (ED(50) = 24 mg/kg) against MES-induced seizure with low neurotoxicity (TD(50) > 4500 mg/kg) in mice, resulting in a PI value of more than 187.5. QUAN-0808 was also tested in chemically induced animal models of seizure (pentylenetetrazole [PTZ], isoniazid [ISO], thiosemicarbazide [THIO] and 3-mercaptopropionic acid [3-MP]) to further investigate the anticonvulsant activity; QUAN-0808 produced significant anticonvulsant activity against seizures induced by ISO, THIO and 3-MP.

  16. Solar photoproduction of hydrogen. IEA technical report of the IEA Agreement of the Production and Utilization of Hydrogen

    SciTech Connect

    Bolton, J.R.

    1996-09-30

    The report was prepared for the International Energy Agency (IEA) Hydrogen Program and represents the result of subtask C, Annex 10 - Photoproduction of Hydrogen. The concept of using solar energy to drive the conversion of water into hydrogen and oxygen has been examined, from the standpoints of potential and ideal efficiencies, measurement of (and how to calculate) solar hydrogen production efficiencies, a survey of the state-of-the-art, and a technological assessment of various solar hydrogen options. The analysis demonstrates that the ideal limit of the conversion efficiency for 1 sun irradiance is {approximately}31% for a single photosystem scheme and {approximately}42% for a dual photosystem scheme. However, practical considerations indicate that real efficiencies will not likely exceed {approximately}10% and {approximately}16% for single and dual photosystem schemes, respectively. Four types of solar photochemical hydrogen systems have been identified: photochemical systems, semiconductor systems, photobiological systems, and hybrid and other systems. A survey of the state-of-the-art of these four types is presented. The four types (and their subtypes) have also been examined in a technological assessment, where each has been examined as to efficiency, potential for improvement, and long-term functionality. Four solar hydrogen systems have been selected as showing sufficient promise for further research and development: (1) Photovoltaic cells plus an electrolyzer; (2) Photoelectrochemical cells with one or more semiconductor electrodes; (3) Photobiological systems; and (4) Photodegradation systems. The following recommendations were presented for consideration of the IEA: (1) Define and measure solar hydrogen conversion efficiencies as the ratio of the rate of generation of Gibbs energy of dry hydrogen gas (with appropriate corrections for any bias power) to the incident solar power (solar irradiance times the irradiated area); (2) Expand support for pilot

  17. A 6.4MB duplication of the alpha-synuclein locus causing fronto-temporal dementia and parkinsonism - phenotype-genotype correlations

    PubMed Central

    Kara, Eleanna; Kiely, Aoife P; Proukakis, Christos; Giffin, Nicola; Love, Seth; Hehir, Jason; Rantell, Khadija; Pandraud, Amelie; Hernandez, Dena G; Nacheva, Elizabeth; Pittman, Alan M; Nalls, Mike A; Singleton, Andrew B; Revesz, Tamas; Bhatia, Kailash P; Quinn, Niall; Hardy, John; Holton, Janice L; Houlden, Henry

    2015-01-01

    Importance SNCA locus duplications are associated with variable clinical features and reduced penetrance but the reasons underlying this variability are unknown. Objective 1) To report a novel family carrying a heterozygous 6.4Mb duplication of the SNCA locus with an atypical clinical presentation strongly reminiscent of frontotemporal dementia (FTD) and late-onset pallidopyramidal syndromes. 2) To study phenotype-genotype correlations in SNCA locus duplications. Design, Setting, Participants and Data sources We report the clinical and neuropathologic features of a family carrying a 6.4Mb duplication of the SNCA locus. To identify candidate disease modifiers, we undertake a genetic analysis in the family and conduct statistical analysis on previously published cases carrying SNCA locus duplication using regression modelling with robust standard errors to account for clustering at the family level. Main outcome measures To assess whether length of the SNCA locus duplication influences disease penetrance and severity, and whether extra-duplication factors have a disease-modifying role. Results We identified a large 6.4Mb duplication of the SNCA locus in this family. Neuropathological analysis showed extensive α-synuclein pathology with minimal phospho-tau pathology. Genetic analysis showed an increased burden of PD-related risk factors and the disease-predisposing H1/H1 MAPT haplotype. Statistical analysis of previously published cases suggested that there is a trend towards increasing disease severity and disease penetrance with increasing duplication size. The corresponding odds ratios (95% CI) from the univariate analyses were 1.17 (0.81 to 1.68) and 1.34 (0.78 to 2.31) respectively. Gender was significantly associated with both disease risk and severity; males compared to females had increased disease risk and severity and the corresponding odds ratios (95% CI) from the univariate analyses were 8.36 (1.97 to 35.42) and 5.55 (1.39 to 22.22) respectively

  18. Theoretical analyses on a flipping mechanism of UV-induced DNA damage

    PubMed Central

    Sato, Ryuma; Harada, Ryuhei; Shigeta, Yasuteru

    2016-01-01

    As for UV-induced DNA damage, which may induce skin cancer in animals and growth inhibition in plants, there are two types of photoproducts, namely cis-sin cyclobutane pyrimidine dimers (CPD) and pyrimidine-pyrimidone (6-4) photoproducts. When they are to be repaired, base-flipping occurs, and they bind to enzymes. However, this process remains relatively unknown at a molecular level. We analyze conformation and interaction energy changes upon base-flipping using classical molecular dynamics (CMD) simulations and ab initio electronic structure calculations. CMD simulations starting with a CPD in the flipped-in and flipped-out states showed that both states were unchanged for 500 ns, indicating the flipped-in and flipped-out processes do not occur spontaneously (without any help of the enzyme) after photo-damage. To deeply understand the reasons, we investigated interaction energy changes among bases upon structure changes during the flipped-in and flipped-out processes using Parallel Cascade Selection-MD (PaCS-MD) simulations at 400 K, followed by a fragment molecular orbital (FMO) method. The total inter-fragment interaction energy (IFIE) between CPD and other bases at the flipped-in state is estimated to be −60.08 kcal/mol. In particular, four bases strongly interact with CPD with interaction energies being −10.96, −13.70, −21.52, and −14.46 kcal/mol each. On the other hand, the total IFIE at the obtained flipped-out state increased to −10.40 kcal/mol by partly losing hydrogen bonds and π-π stacking interactions, respectively. These results clearly indicate that the base-flipping process of DNA lesions occurs with the help of external forces like interactions with appropriate enzymes such as photolyases.

  19. A Chandra Observation of the Luminous Northeastern Rim of the Galactic Supernova Remnant W28 (G6.4-0.1)

    NASA Astrophysics Data System (ADS)

    Pannuti, Thomas

    2016-06-01

    We present an analysis of a pointed observation made of the luminous northeastern rim of the Galactic supernova remnant (SNR) W28 (G6.4-0.1) with the Chandra X-ray Observatory. W28 is the archetype for the class of SNRs known as the mixed-morphology SNRs: sources in this class of objects feature a shell-like morphology with a contrasting center-filled X-ray morphology. Almost unique amongst mixed-morphology SNRs, W28 exhibits a luminous northeastern rim which is detected in the X-ray, optical and radio: this rim is also the site of a vigorous interaction between W28 and adjacent molecular clouds, as evidenced by the high concentration of hydroxyl (OH) masers seen at this rim. Our pointed Chandra observation of this rim is the highest angular X-ray observation made of this feature: initial analysis and results will be presented and discussed.

  20. Solvent effects on the oxidation (electron transfer) reaction of [Fe(CN) 6] 4- by [Co(NH 3) 5pz] 3+

    NASA Astrophysics Data System (ADS)

    Muriel, F.; Jiménez, R.; López, M.; Prado-Gotor, R.; Sánchez, F.

    2004-03-01

    Solvent effects on the title reaction were studied in different reaction media constituted by water and organic cosolvents (methanol, tert-butyl alcohol, ethyleneglycol and glucose) at 298.2 K. The results are considered in light of the Marcus-Hush approach for electron transfer reactions. Variations of the electron transfer rate constant are shown to be mainly due to changes in the reaction free energy. On the other hand the energies of the MMCT band, corresponding to the optical electron transfer within the ion pair [Fe(CN) 6] 4-/[Co(NH 3) 5pz] 3+, in the different reaction media, have been obtained. The activation free energies of the thermal electron transfer process have been calculated from the band ( Eop) data, and compared with those obtained from the kinetic study. Quantitative agreement is found between the two series of data. This shows the possibility of estimating activation free energies for electron transfer reactions from static (optical) measurements.

  1. Viscoelastic Response of the Titanium Alloy Ti-6-4: Experimental Identification of Time- and Rate-Dependent Reversible and Irreversible Deformation Regions

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley A.; Arnold, Steven M.

    2014-01-01

    In support of an effort on damage prognosis, the viscoelastic behavior of Ti-6Al-4V (Ti-6-4) was investigated. This report documents the experimental characterization of this titanium alloy. Various uniaxial tests were conducted to low load levels over the temperature range of 20 to 538 C to define tensile, creep, and relaxation behavior. A range of strain rates (6x10(exp -7) to 0.001/s) were used to document rate effects. All tests were designed to include an unloading portion, followed by a hold time at temperature to allow recovery to occur either at zero stress or strain. The titanium alloy was found to exhibit viscoelastic behavior below the "yield" point and over the entire range of temperatures (although at lower temperatures the magnitude is extremely small). These experimental data will be used for future characterization of a viscoelastic model.

  2. Conserved Negative Charges in the N-terminal Tetramerization Domain Mediate Efficient Assembly of Kv2.1 and Kv2.1/Kv6.4 Channels*

    PubMed Central

    Bocksteins, Elke; Labro, Alain J.; Mayeur, Evy; Bruyns, Tine; Timmermans, Jean-Pierre; Adriaensen, Dirk; Snyders, Dirk J.

    2009-01-01

    Voltage-gated potassium (Kv) channels are transmembrane tetramers of individual α-subunits. Eight different Shaker-related Kv subfamilies have been identified in which the tetramerization domain T1, located on the intracellular N terminus, facilitates and controls the assembly of both homo- and heterotetrameric channels. Only the Kv2 α-subunits are able to form heterotetramers with members of the silent Kv subfamilies (Kv5, Kv6, Kv8, and Kv9). The T1 domain contains two subdomains, A and B box, which presumably determine subfamily specificity by preventing incompatible subunits to assemble. In contrast, little is known about the involvement of the A/B linker sequence. Both Kv2 and silent Kv subfamilies contain a fully conserved and negatively charged sequence (CDD) in this linker that is lacking in the other subfamilies. Neutralizing these aspartates in Kv2.1 by mutating them to alanines did not affect the gating properties, but reduced the current density moderately. However, charge reversal arginine substitutions strongly reduced the current density of these homotetrameric mutant Kv2.1 channels and immunocytochemistry confirmed the reduced expression at the plasma membrane. Förster resonance energy transfer measurements using confocal microscopy showed that the latter was not due to impaired trafficking, but to a failure to assemble the tetramer. This was further confirmed with co-immunoprecipitation experiments. The corresponding arginine substitution in Kv6.4 prevented its heterotetrameric interaction with Kv2.1. These results indicate that these aspartates (especially the first one) in the A/B box linker of the T1 domain are required for efficient assembly of both homotetrameric Kv2.1 and heterotetrameric Kv2.1/silent Kv6.4 channels. PMID:19717558

  3. Exclusive heavy vector meson photoproduction in hadronic collisions at the LHC: Predictions of the color glass condensate model for Run 2 energies

    NASA Astrophysics Data System (ADS)

    Gonçalves, V. P.; Moreira, B. D.; Navarra, F. S.

    2017-03-01

    In this paper, we update the predictions for exclusive J /Ψ , Ψ (2 S ), and ϒ photoproduction in proton-proton and nucleus-nucleus collisions at the Run 2 LHC energies obtained with the color dipole formalism and considering the impact-parameter color glass condensate model (bCGC) for the forward dipole-target scattering amplitude. The impact of the charm mass on the predictions is investigated, and a comparison with the LHCb data on rapidity distributions and photon-hadron cross sections is presented. Our results demonstrate that the current data can be quite well described by the bCGC model, which takes into account nonlinear effects in the QCD dynamics and reproduces the very precise HERA data, without introducing any additional effect or free parameter.

  4. Coherent J/Psi photoproduction in ultra-peripheral PbPb collisions at sqrt(s[NN]) = 2.76 TeV with the CMS experiment

    SciTech Connect

    Khachatryan, Vardan; et al.

    2016-05-23

    The cross section for coherent J/psi photoproduction accompanied by at least one neutron on one side of the interaction point and no neutron activity on the other side, X[n]0[n], is measured with the CMS experiment in ultra-peripheral PbPb collisions at sqrt(s[NN]) = 2.76 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 159 inverse microbarns, collected during the 2011 PbPb run. The J/psi mesons are reconstructed in the dimuon decay channel, while neutrons are detected using zero degree calorimeters. The measured cross section is d sigma[coh,X[n]0[n

  5. Accessing transverse nucleon and gluon distributions in heavy nuclei using coherent vector meson photoproduction at high energies in ion ultraperipheral collisions

    NASA Astrophysics Data System (ADS)

    Guzey, V.; Strikman, M.; Zhalov, M.

    2017-02-01

    By using the theoretical approaches that describe well the available data on t -integrated coherent photoproduction of light and heavy vector mesons in Pb-Pb ultraperipheral collisions (UPCs) at the Large Hadron Collider (LHC) in Run 1, we calculate the momentum transfer distributions for this process for ρ and J /ψ vector mesons in the kinematics of Run 2 at the LHC. We demonstrate that nuclear shadowing not only suppresses the absolute value of the cross sections but also shifts the momentum transfer distributions toward smaller values of the momentum transfer |t | . This result can be interpreted as a broadening in the impact parameter space of the effective nucleon density in nuclei by 14% in the case of ρ and the nuclear gluon distribution by 5%-11% in the case of J /ψ .

  6. Light Vector Meson Photoproduction off of 1H at Jefferson Lab and p-w Interference in the Leptonic Decay Channel

    SciTech Connect

    Djalali, Chaden; Paolone, Michael; Weygand, Dennis; Wood, Mike H.

    2014-09-01

    Although the phenomena of r – w interference has been studied at great length in pionic decay channel over the past 50 years, a study of the interference in a purely electromagnetic production and decay channel has never been performed on an elementary proton target until now. The only published photo-production data of the r - w leptonic decay channel was obtained in the early seventies on C and Be. An investigation of the r - w interference on a Hydrogen was recently completed at Jefferson Lab with the CLAS detector. The di-lepton spectra was fit with two inter- fering relativistic Breit-Wigner functions, and the interference phase was extracted. Preliminary results will be compared to the previous experimental studies in nuclei.

  7. Cytotoxicity on Allium cepa of the two main sulcotrione photoproducts, xanthene-1,9-dione-3,4-dihydro-6-methylsulphonyl and 2-chloro-4-mesylbenzoic acid.

    PubMed

    Goujon, Eric; Richard, Claire; Goupil, Pascale; Ledoigt, Gérard

    2015-10-01

    The cytotoxic effects of 2-chloro-4-mesylbenzoic acid (CMBA) and xanthene-1,9-dione-3,4-dihydro-6-methylsulphonyl (XDD), the two main photoproducts of sulcotrione, were investigated on Allium root meristematic cells at different concentrations. Degradation of sulcotrione was correlated to mitotic index decrease, together with increasing anomaly and c-mitosis frequencies. Mitotic index significantly decreased with increasing XDD and CMBA concentrations. Cell frequency with abnormal chromosomes increased with CMBA or XDD application rates. In contrast, CMBA induced a low micronucleus rate even for high concentrations while XDD increased the micronucleus ratio. C-mitoses, chromosomal aberrations due to an inactivation of the spindle, were enhanced by CMBA treatments but not by XDD. The photochemical degradation process of the pesticide can change the risk for the environment.

  8. Coherent ρ 0 photoproduction in ultra-peripheral Pb-Pb collisions at $ \\sqrt{s_{\\mathrm{NN}}}=2.76 $ TeV

    SciTech Connect

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Chunhui, Z.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D’Erasmo, G.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J. -Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Luz, P. H. F. N. D.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal’Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Masui, H.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Mcdonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miskowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Ploskon, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J. -P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I. -K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2015-09-15

    We report the first measurement at the LHC of coherent photoproduction of ρo mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for ρo production are studied in the π+π- decay channel at mid-rapidity. The production cross section in the rapidity range |y| < 0.5 is found to be dσ/dy = 425 ± 10(stat.)-50+ 42 (sys.) mb. Coherent ρo production is studied with and without requirement of nuclear breakup, and the fractional yields for various breakup scenarios are presented. Lastly, the results are compared with those from lower energies and with model predictions.

  9. Oral Contribution: varphi-meson photoproduction off the protons by using linearly polarized photons in the mid- to higher-t regimes at threshold energies

    NASA Astrophysics Data System (ADS)

    Salamanca, Julian; Cole, Philip L.

    2009-12-01

    Observables from vector meson photoproduction by linearly-polarized photons can be expressed in term of bilinear combinations of helicity amplitudes parameterized by the Spin Density Matrix Elements (SDMEs). These SDMEs give straightforward relations for understanding the nature of the parity exchange at threshold energies, as well as for extracting signatures of the Okubo-Zweig-Iizuka violation. This paper will show preliminary measurements of SDMEs for vec gammap → varphip in the photon energy range of 1.7 to 1.9 GeV (momentum transfer squared t range of -1.2 to -0.25 GeV2) and 1.9 to 2.1 GeV (t range of -1.4 to -0.25 GeV2) from the g8b experimental data collected in the summer of 2005 in the Hall B of Jefferson Lab.

  10. Photoproduction of vector mesons in ultra-peripheral p–Pb and Pb–Pb collisions at the LHC with the ALICE experiment

    SciTech Connect

    Broz, Michal

    2015-04-10

    Vector mesons are copiously produced in ultra-peripheral collisions. In these collisions, the impact parameter is larger than the sum of the radii of the two projectiles, implying that electromagnetic processes become dominant. The cross section of production of vector mesons is expected to be sensitive to the gluon distribution and can therefore probe nuclear gluon shadowing (Pb–Pb) and the gluon structure function in the nucleon (p-Pb). The ALICE Collaboration has performed the first measurements of the production of ρ{sup 0}, J/ψ and ψ/(2S) in Pb–Pb ultra-peripheral collision as well as the cross section for exclusive J/ψ photoproduction off protons in ultra-peripheral proton-lead collisions at the LHC. The results are compared to the STARLIGHT Monte Carlo and to QCD based models.

  11. Coherent ψ(2S) photo-production in ultra-peripheral Pbsbnd Pb collisions at √{sNN} = 2.76 TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Chunhui, Z.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D'Erasmo, G.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Luz, P. H. F. N. D.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Masui, H.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Mcdonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2015-12-01

    We have performed the first measurement of the coherent ψ (2 S) photo-production cross section in ultra-peripheral Pbsbnd Pb collisions at the LHC. This charmonium excited state is reconstructed via the ψ (2 S) →l+l- and ψ (2 S) → J / ψπ+π- decays, where the J / ψ decays into two leptons. The analysis is based on an event sample corresponding to an integrated luminosity of about 22 μb-1. The cross section for coherent ψ (2 S) production in the rapidity interval - 0.9 < y < 0.9 is d σψ(2 S)coh/ dy = 0.83 ± 0.19 (stat + syst) mb. The ψ (2 S) to J / ψ coherent cross section ratio is 0.34-0.07+0.08 (stat + syst). The obtained results are compared to predictions from theoretical models.

  12. Coherent ρ 0 photoproduction in ultra-peripheral Pb-Pb collisions at √{s_{NN}}=2.76 TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Chunhui, Z.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D'Erasmo, G.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Luz, P. H. F. N. D.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Masui, H.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Mcdonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miskowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Ploskon, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2015-09-01

    We report the first measurement at the LHC of coherent photoproduction of ρ 0 mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for ρ 0 production are studied in the π + π - decay channel at mid-rapidity. The production cross section in the rapidity range | y| < 0.5 is found to be d σ/d y = 425 ± 10(stat.) - 50 + 42 (sys.) mb. Coherent ρ 0 production is studied with and without requirement of nuclear breakup, and the fractional yields for various breakup scenarios are presented. The results are compared with those from lower energies and with model predictions. [Figure not available: see fulltext.

  13. Coherent ρ 0 photoproduction in ultra-peripheral Pb-Pb collisions at $$ \\sqrt{s_{\\mathrm{NN}}}=2.76 $$ TeV

    DOE PAGES

    Adam, J.; Adamová, D.; Aggarwal, M. M.; ...

    2015-09-15

    We report the first measurement at the LHC of coherent photoproduction of ρo mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for ρo production are studied in the π+π- decay channel at mid-rapidity. The production cross section in the rapidity range |y| < 0.5 is found to be dσ/dy = 425 ± 10(stat.)-50+ 42 (sys.) mb. Coherent ρo production is studied with and without requirement of nuclear breakup, and the fractional yields for various breakup scenarios are presented. Lastly, the results are compared with those from lower energies and with model predictions.

  14. Monohydroxylated Polybrominated Diphenyl Ethers (OH-PBDEs) and Dihydroxylated Polybrominated Biphenyls (di-OH-PBBs): Novel Photoproducts of 2,6-Dibromophenol

    PubMed Central

    Zhao, Hongxia; Jiang, Jingqiu; Wang, Yanli; Lehmler, Hans-Joachim; Buettner, Garry R.; Quan, Xie; Chen, Jingwen

    2016-01-01

    Hydroxylated polybromodiphenyl ethers (OH-PBDEs) are emerging aquatic pollutants, but their origins in the environment are not fully understood. There is evidence that OH-PBDEs are formed from bromophenols, but the underlying transformation processes remain unknown. Here we investigate if the photoformation of OH-PBDEs from 2,6-dibromophenol in aqueous solution involves 2,6-bromophenoxyl radicals. After UV irradiation of an aqueous 2,6-dibromophenol solution, HPLC-LTQ-Orbitrap MS and GC/MS analysis revealed the formation of a OH-PBDE and a dihydroxylated polybrominated biphenyl (di-OH-PBB). Both dimeric photoproducts were tentatively identified as 4′-OH-BDE73 and 4,4′-di-OH-PBB80. In addition, three debromination products (4-OH-BDE34, 4′-OH-BDE27, and 4,4′-di-OH-PBBs) were observed. Electron paramagnetic resonance spectroscopy revealed the presence of a 2,6-dibromophenoxyl radical with a six-line spectrum (aH (2 meta) = 3.45 G, aH (1 para) = 1.04 G, g = 2.0046) during irradiation of a 2,6-dibromophenol solution in water. The 2,6-dibromophenoxyl radical had a relatively long half-life (122 ± 5 μs) according to laser flash photolysis experiments. The para-para C-C and O-para-C couplings of these 2,6-dibromophenoxyl radicals are consistent with the observed formation of both dimeric OH-PBDE and di-OH-PBB photoproducts. These findings show that bromophenoxyl radical-mediated phototransformation of bromophenols is a source of OH-PBDEs and di-OH-PBBs in aqueous environments that requires further attention. PMID:26545041

  15. Photoproduction of catalase-insensitive peroxides on the donor side of manganese-depleted photosystem II: evidence with a specific fluorescent probe.

    PubMed

    Khorobrykh, Sergey A; Khorobrykh, Andrei A; Yanykin, Denis V; Ivanov, Boris N; Klimov, Vyacheslav V; Mano, Jun'ichi

    2011-12-13

    The photoproduction of organic peroxides (ROOH) in photosystem II (PSII) membranes was studied using the fluorescent probe Spy-HP. Two types of peroxide, highly lipophilic ones and relatively hydrophilic ones, were distinguished by the rate of reaction with Spy-HP; the former oxidized Spy-HP to the higher fluorescent form Spy-HPOx within 5 min, while the latter did so very slowly (the reaction was still not completed after 180 min). The level of photoproduction of these peroxides was significantly larger in the alkaline-treated, Mn-depleted PSII membranes than that in the untreated membranes, and it was suppressed by an artificial electron donor (diphenylcarbazide or ferrocyanide) and by the electron transport inhibitor diuron. Postillumination addition of Fe(2+) ions, which degrade peroxides by the Fenton mechanism, abolished the accumulation of Spy-HPOx, but catalase did not change the peroxide level, indicating that the detected species were organic peroxides, excluding H(2)O(2). These results agreed with our previous observation of an electron transport-dependent O(2) consumption on the PSII donor side and indicated that ROOH accumulated via a radical chain reaction that started with the formation of organic radicals on the donor side. Illumination (λ > 600 nm; 1500 μmol of photons m(-2) s(-1)) of the Mn-depleted PSII membranes for 3 min resulted in the formation of nearly 200 molecules of hydrophilic ROOH per reaction center, but only four molecules of highly lipophilic ROOH. The limited formation of the latter was due to the limited supply of its precursor to the reaction, suggesting that it represented structurally fixed peroxides, i.e., either protein peroxides or peroxides of the lipids tightly bound to the core complex. These ROOH forms, likely including several species derived from lipid peroxides, may mediate the donor side-induced photoinhibition of PSII via protein modification.

  16. Expression of a clostridial [FeFe]-hydrogenase in Chlamydomonas reinhardtii prolongs photo-production of hydrogen from water splitting

    SciTech Connect

    Noone, Seth; Ratcliff, Kathleen; Davis, ReAnna; Subramanian, Venkataramanan; Meuser, Jonathan; Posewitz, Matthew C.; King, Paul W.; Ghirardi, Maria L.

    2016-12-24

    The high oxygen (O2) sensitivity of green algal [FeFe]-hydrogenases is a significant limitation for the sustained production of hydrogen gas (H2) from photosynthetic water splitting. To address this limitation we replaced the native [FeFe]-hydrogenases with a more O2-tolerant clostridial [FeFe]-hydrogenase CaI in Chlamydomonas reinhardtii strain D66ΔHYD (hydA1hydA2) that contains insertionally inactivated [FeFe]-hydrogenases genes. Expression and translocation of CaI in D66ΔHYD led to the recovery of H2 photoproduction at ~ 20% of the rates of the wild-type parent strain D66. We show for the first time that a bacterial [FeFe]-hydrogenase can be expressed, localized and matured to a catalytically active form that couples to photosynthetic electron transport in the green alga C. reinhardtii. The lower rates of O2 inactivation of CaI led to more sustained H2 photoproduction when cultures were challenged with O2 or kept under prolonged illumination at solar intensities. Lastly, these results provide new insights into the requisites for attaining photobiological H2 production from water splitting using a more O2-tolerant hydrogenase.

  17. Toxicity of a PAH photooxidation product to the bacteria Photobacterium phosphoreum and the duckweed Lemna gibba: Effects of phenanthrene and its primary photoproduct, phenanthrenequinone

    SciTech Connect

    McConkey, B.J.; Duxbury, C.L.; Dixon, D.G.; Greenberg, B.M.

    1997-05-01

    Phenanthrene (PHE) undergoes a significant increase in toxicity after exposure to simulated or natural sunlight in aqueous media, coincident with the appearance of PHE photoproducts. To investigate whether the primary photoproduct of PHE, 9,10-phenanthrenequinone (PHEQ), contributes to the increased hazards of solutions containing photomodified PHE, toxicity assays were conducted using the marine bacteria Photobacterium phosphoreum and the aquatic plant Lemna gibba (duckweed). Photobacterium phosphoreum was exposed to PHE, PHEQ, a photomodified PHE mixture containing known amounts of PHE and PHEQ (pmPHE), and a mixture mimicking the amounts of PHE and PHEQ in the pmPHE mixture. The bacteria were found to be equally sensitive to PHE in simulated solar radiation or darkness, with an EC50 of 0.53 mg/L. In both darkness or SSR, solutions containing PHEQ (with or without PHE) all exhibited an EC50 of 0.06 to 0.10 mg/L based on PHEQ concentrations, indicating that PHEQ was the primary active component of the pmPHE mixture. Lemna gibba was tested in SSR and visible light with PHE, PHEQ, and the pmPHE mixture. The calculated EC50 for PHE was 3.5 mg/L in SSR and 10.8 mg/L in visible light, showing that the presence of UV radiation in the SSR source increased the phytotoxicity of PHE. Strikingly, PHEQ was much more toxic to L. gibba than PHE in a light-independent manner. Thus, for both P. phosphoreum and L. gibba the major photooxidation product of PHE in SSR, PHEQ, is the more toxic of the two chemicals.

  18. Plastidial Expression of Type II NAD(P)H Dehydrogenase Increases the Reducing State of Plastoquinones and Hydrogen Photoproduction Rate by the Indirect Pathway in Chlamydomonas reinhardtii1.

    PubMed

    Baltz, Anthony; Dang, Kieu-Van; Beyly, Audrey; Auroy, Pascaline; Richaud, Pierre; Cournac, Laurent; Peltier, Gilles

    2014-07-01

    Biological conversion of solar energy into hydrogen is naturally realized by some microalgae species due to a coupling between the photosynthetic electron transport chain and a plastidial hydrogenase. While promising for the production of clean and sustainable hydrogen, this process requires improvement to be economically viable. Two pathways, called direct and indirect photoproduction, lead to sustained hydrogen production in sulfur-deprived Chlamydomonas reinhardtii cultures. The indirect pathway allows an efficient time-based separation of O2 and H2 production, thus overcoming the O2 sensitivity of the hydrogenase, but its activity is low. With the aim of identifying the limiting step of hydrogen production, we succeeded in overexpressing the plastidial type II NAD(P)H dehydrogenase (NDA2). We report that transplastomic strains overexpressing NDA2 show an increased activity of nonphotochemical reduction of plastoquinones (PQs). While hydrogen production by the direct pathway, involving the linear electron flow from photosystem II to photosystem I, was not affected by NDA2 overexpression, the rate of hydrogen production by the indirect pathway was increased in conditions, such as nutrient limitation, where soluble electron donors are not limiting. An increased intracellular starch was observed in response to nutrient deprivation in strains overexpressing NDA2. It is concluded that activity of the indirect pathway is limited by the nonphotochemical reduction of PQs, either by the pool size of soluble electron donors or by the PQ-reducing activity of NDA2 in nutrient-limited conditions. We discuss these data in relation to limitations and biotechnological improvement of hydrogen photoproduction in microalgae.

  19. Biological hydrogen photoproduction

    SciTech Connect

    Brand, L.E.; Luo, Yao-Hua; Tsuzuki, T.

    1996-10-01

    The authors maintain a culture collection of over 2,500 cyanobacteria and photosynthetic bacteria and 2,000 eukaryotic algae for research on H{sub 2} biophotoproduction as well as other projects. A high H{sub 2}-producing strain Synechococcus sp. Miami BG 043511 from the collection has been used to examine H{sub 2} production in relation to water photolysis and substance degradation, high O{sub 2}-tolerance characterization of nitrogenase, and interactive effects of light intensity and cell density on H{sub 2} production and its stable isotope fractionation. When cellular carbohydrate is depleted, no H{sub 2} production occurs. However, when pyruvate or glucose is added, H{sub 2} production begins. On the other hand, when glucose and DCMU are added to cellular carbohydrate-depleted cells from synchronous cultures, H{sub 2} production is inhibited compared with that with glucose addition alone. These results indicate that water photolysis alone cannot directly induce H{sub 2} production, but it acts together with cellular glucose degradation to enhance H{sub 2} production. The cyanobacteria strain, unlike unicellular green algae, shows no significant difference in H{sub 2} evolution with or without O{sub 2} removal reagent (Fieser`s solution: sodium dithionite/sodium anthraquinon-{beta}-sulfonate/KOH water solution) treated. When 10-hr cells are incubated in the dark with injected O{sub 2}, H{sub 2} evolution is induced, accompanied by O{sub 2} consumption. When zero-hr cells of synchronous cultures are incubated with 5% CO{sub 2}, the carbon is assimilated under light and O{sub 2} accumulates. Even when cells are under aerobic conditions with 25 {mu}mol O{sub 2}/Mg dry wt., H{sub 2} production is still induced, comparable with that under anaerobic conditions. The H{sub 2}-light curve has a pattern similar to CO{sub 2}-light curves, the light saturation point increasing, and the magnitude of H{sub 2} accumulation decreasing, with increasing cell density.

  20. Charged Pion Photoproduction

    SciTech Connect

    Haiyan Gao, Wei Chen

    2009-12-01

    We extracted the differential cross section for the gn --> pi-p process from a deuterium target using the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (theta c.m.) between 50 deg. and 115 deg. We confirm a previous indication of a broad enhancement around a c.m. energy (sqrt s) of 2.1 GeV at theta c.m. =90 deg. in the scaled differential cross section, s^7 ds/dt and a rapid fall-off in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for theta c.m. from 70 deg. to 10 deg.

  1. Faster DNA Repair of Ultraviolet-Induced Cyclobutane Pyrimidine Dimers and Lower Sensitivity to Apoptosis in Human Corneal Epithelial Cells than in Epidermal Keratinocytes

    PubMed Central

    Mallet, Justin D.; Bastien, Nathalie; Gendron, Sébastien P.; Rochette, Patrick J.

    2016-01-01

    Absorption of UV rays by DNA generates the formation of mutagenic cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts (6-4PP). These damages are the major cause of skin cancer because in turn, they can lead to signature UV mutations. The eye is exposed to UV light, but the cornea is orders of magnitude less prone to UV-induced cancer. In an attempt to shed light on this paradox, we compared cells of the corneal epithelium and the epidermis for UVB-induced DNA damage frequency, repair and cell death sensitivity. We found similar CPD levels but a 4-time faster UVB-induced CPD, but not 6-4PP, repair and lower UV-induced apoptosis sensitivity in corneal epithelial cells than epidermal. We then investigated levels of DDB2, a UV-induced DNA damage recognition protein mostly impacting CPD repair, XPC, essential for the repair of both CPD and 6-4PP and p53 a protein upstream of the genotoxic stress response. We found more DDB2, XPC and p53 in corneal epithelial cells than in epidermal cells. According to our results analyzing the protein stability of DDB2 and XPC, the higher level of DDB2 and XPC in corneal epithelial cells is most likely due to an increased stability of the protein. Taken together, our results show that corneal epithelial cells have a better efficiency to repair UV-induced mutagenic CPD. On the other hand, they are less prone to UV-induced apoptosis, which could be related to the fact that since the repair is more efficient in the HCEC, the need to eliminate highly damaged cells by apoptosis is reduced. PMID:27611318

  2. Construction and 13C NMR signal-amplification efficiency of a dynamic nuclear polarizer at 6.4 T and 1.4 K

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Ferguson, Sarah; Taylor, David; McDonald, George; Lumata, Lloyd

    Dissolution dynamic nuclear polarization (DNP) is a rapidly emerging technique in biomedical and metabolic imaging since it amplifies the liquid-state nuclear magnetic resonance (NMR) and imaging (MRI) signals by >10,000-fold. Originally used in nuclear scattering experiments, DNP works by creating a non-Boltzmann nuclear spin distribution by transferring the high electron (γ = 28,000 MHz/T) thermal polarization to the nuclear spins via microwave irradiation of the sample at high magnetic field and low temperature. A dissolution device is used to rapidly dissolve the frozen sample and consequently produces an injectable ``hyperpolarized'' liquid at physiologically-tolerable temperature. Here we report the construction and performance evaluation of a dissolution DNP hyperpolarizer at 6.4 T and 1.4 K using a continuous-flow cryostat. The solid and liquid-state 13C NMR signal enhancement levels of 13C acetate samples doped with trityl OX063 and 4-oxo-TEMPO free radicals will be discussed and compared with the results from the 3.35 T commercial hyperpolarizer. This work is supported by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  3. Blind thrust rupture of the 2015 Mw 6.4 Pishan earthquake in the Northwest Tibetan Plateau by joint inversion of InSAR and seismic data

    NASA Astrophysics Data System (ADS)

    Zhang, Guohong; Shan, Xinjian; Zhang, Yingfeng; Hetland, Eric; Qu, Chunyan; Feng, Guangcai

    2016-12-01

    The July 3rd, 2015 Pishan, China Mw 6.4 earthquake occurred within the Hetian fold belt, a frontal thrust region between the Northwestern Tibetan Plateau and the Tarim basin. We investigate the fault geometry and the rupture process of the Pishan earthquake based on joint inversion of teleseismic body waves and InSAR measurements. Our results show that the top of the fault that ruptured in the Pishan earthquake is buried 5 ± 2 km beneath the surface and that the earthquake ruptured only a segment of a deeply-seated detachment lying under the Hetian fold belt. Our inferred coseismic slip model shows two slip asperities, located in the depth range of about 7-9 km and 10-11 km. Additionally, we resolve a slip deficit region between the slip asperities, which might indicate friction heterogeneity on the fault plane. The earthquake ruptured for ∼15 s, releasing a total seismic moment of 4.7 × 1018 N m. We also show that the latest Pishan earthquake caused positive Coulomb stress changes on back thrust faults, potentially decreasing the time to the next earthquake on those faults. Based on our Pishan coseismic slip model, along with both the trend of the anticline system and the pattern of coseismic deformation, we envision an ongoing east-west extensional growth of the anticlines in the Western Kunlun frontal thrust region in addition to the northern underthrusting of the Northwestern Tibetan Plateau below the Tarim basin.

  4. Synthesis, molecular docking and biological evaluation of novel 6-(4-(4-aminophenylsulfonyl)phenylamino)-5H-benzo[a]phenothiazin-5-one derivatives

    NASA Astrophysics Data System (ADS)

    Ravichandiran, Palanisamy; Athinarayanan, Jegan; Premnath, Dhanaraj; Periasamy, Vaiyapuri Subbarayan; Alshatwi, Ali A.; Vasanthkumar, Samuel

    2015-03-01

    A novel series of 6-(4-(4-aminophenylsulfonyl)phenylamino)-5H-benzo[a]phenothiazin-5-one derivatives have been synthesized and examined for their in vitro antibacterial activity against a panel of Gram-positive and Gram-negative bacteria. Among these, N-(4-(4-(5-oxo-5H-benzo[a]phenothiazin-6-ylamino)phenylsulfonyl)phenyl)-3,5-bis(trifluoromethyl)benzamide (3n) (0.4 μg/mL) and 4-ethyl-N-(4-(4-(5-oxo-5H-benzo[a]phenothiazin-6-ylamino)phenylsulfonyl)phenyl)benzamide (3l) (0.6 μg/mL) systems exhibited a potent inhibitory activity against Gram-positive organism Bacillus subtilis, when compare to the other synthesized compounds. Sparfloxacin (9.76 μg/mL), Norfloxacin (no activity) were employed as the standard drugs. An evaluation of the cytotoxicity of the title compounds (1, 2, 3a-n) revealed that they displayed low toxicity (26-115 mg/L) against cervical cancer cell line (SiHa). The results of these studies suggest that, phenothiazin-5-one derivatives are interesting binding agents for the development of new Gram-positive and Gram-negative antibacterial agents. To understand the interactions with protein receptors, docking simulation was done with crystal structures of B.subtilis (YmaH) and histone deacetylase (HDAC8) to determine the probable binding conformation.

  5. Adipic acid-2,4-diamino-6-(4-meth-oxy-phen-yl)-1,3,5-triazine (1/2).

    PubMed

    Thanigaimani, Kaliyaperumal; Razak, Ibrahim Abdul; Arshad, Suhana; Jagatheesan, Rathinavel; Santhanaraj, Kulandaisamy Joseph

    2012-10-01

    The asymmetric unit of the title compound, 2C(10)H(11)N(5)O·C(6)H(10)O(4), consists of a 2,4-diamino-6-(4-meth-oxy-phen-yl)-1,3,5-triazine mol-ecule and one-half mol-ecule of adipic acid which lies about an inversion center. The triazine ring makes a dihedral angle of 12.89 (4)° with the adjacent benzene ring. In the crystal, the components are linked by N-H⋯O and O-H⋯N hydrogen bonds, thus generating a centrosymmetric 2 + 1 unit of triazine and adipic acid mol-ecules with R(2) (2)(8) motifs. The triazine mol-ecules are connected to each other by N-H⋯N hydrogen bonds, forming an R(2) (2)(8) motif and a supra-molecular ribbon along the c axis. The 2 + 1 units and the supra-molecular ribbons are further inter-linked by weak N-H⋯O, C-H⋯O and C-H⋯π inter-actions, resulting in a three-dimensional network.

  6. The 26 May 2006 magnitude 6.4 Yogyakarta earthquake south of Mt. Merapi volcano: Did lahar deposits amplify ground shaking and thus lead to the disaster?

    NASA Astrophysics Data System (ADS)

    Walter, T. R.; Wang, R.; Luehr, B.-G.; Wassermann, J.; Behr, Y.; Parolai, S.; Anggraini, A.; Günther, E.; Sobiesiak, M.; Grosser, H.; Wetzel, H.-U.; Milkereit, C.; Sri Brotopuspito, P. J. K.; Harjadi, P.; Zschau, J.

    2008-05-01

    Indonesia is repeatedly unsettled by severe volcano- and earthquake-related disasters, which are geologically coupled to the 5-7 cm/a tectonic convergence of the Australian plate beneath the Sunda Plate. On Saturday, 26 May 2006, the southern coast of central Java was struck by an earthquake at 2254 UTC in the Sultanate Yogyakarta. Although the magnitude reached only M w = 6.4, it left more than 6,000 fatalities and up to 1,000,000 homeless. The main disaster area was south of Mt. Merapi Volcano, located within a narrow topographic and structural depression along the Opak River. The earthquake disaster area within the depression is underlain by thick volcaniclastic deposits commonly derived in the form of lahars from Mt. Merapi Volcano, which had a major influence leading to the disaster. In order to more precisely understand this earthquake and its consequences, a 3-month aftershock measurement campaign was performed from May to August 2006. We here present the first location results, which suggest that the Yogyakarta earthquake occurred at 10-20 km distance east of the disaster area, outside of the topographic depression. Using simple model calculations taking material heterogeneity into account we illustrate how soft volcaniclastic deposits may locally amplify ground shaking at distance. As the high degree of observed damage may have been augmented by the seismic response of the volcaniclastic Mt. Merapi deposits, this work implies that the volcano had an indirect effect on the level of earthquake destruction.

  7. 6-(4-Amino-2-butyl-imidazoquinolyl)-norleucine: Toll-like receptor 7 and 8 agonist amino acid for self-adjuvanting peptide vaccine.

    PubMed

    Fujita, Yoshio; Hirai, Kazuyuki; Nishida, Keigo; Taguchi, Hiroaki

    2016-05-01

    Generally, small peptides by themselves are weak to induce antibody responses. Toll-like receptor (TLR) ligands are attractive candidates of vaccine adjuvants to improve their antigenicity. The covalent conjugation of TLR ligands with antigens to produce self-adjuvanting peptide vaccine is a promising approach. Based on the structure of TLR7/8 ligands, a series of synthetic amino acids 6-imidazoquinolyl-norleucines were synthesized, wherein an imidazoquinoline structure as the TLR7/8 agonistic pharmacophores was constructed on the ε-NH2 group of Lys. Of them, 6-(4-amino-2-butyl-imidazoquinolyl)-norleucine showed the most potent TLR7 and TLR8 agonistic activities with EC50 values of 8.55 and 106 μM, respectively. Subsequently, mice were immunized with the influenza A virus M2e antigen mixed with or covalently conjugated to the TLR7/8 agonist amino acid, which led to induction of M2e specific antibody productions in the absence of other adjuvant. We successfully developed a novel efficient tool for self-adjuvanting peptide vaccines targeting TLR7/8.

  8. High-elevation paleoenvironmental change during MIS 6-4 in the central Rockies of Colorado as determined from pollen analysis

    NASA Astrophysics Data System (ADS)

    Anderson, R. Scott; Jiménez-Moreno, Gonzalo; Ager, Thomas; Porinchu, David F.

    2014-11-01

    Paleoecological studies from Rocky Mountain (USA) high elevations encompassing the previous interglacial (MIS 5e) are rare. The ~ 10-m composite profile from the Ziegler Reservoir fossil site (2705 m asl) of central Colorado allows us to determine paleoenvironments from Marine Oxygen Isotope Stages (MIS) 6- 4 using pollen zones that are approximately equivalent to marine oxygen isotope stages. During Pollen Zone (PZ) 6 time, pollen assemblages dominated by Artemisia (sagebrush) suggest that alpine tundra or steppe occurred nearby. The transition to PZ 5e was characterized by a rapid increase in tree pollen, initially Picea (spruce) and Pinus (pine) but also Quercus (oak) and Pseudotsuga menziesii (Douglas-fir). Non-arboreal pollen (NAP) types increased during PZ 5d, while Abies (fir) and Juniperus (juniper) increased during PZ 5c. Pollen evidence suggests that temperatures during PZ 5b were as cold as during PZ 6, with the site again surrounded by alpine tundra. Picea dominated during PZ 5a before the onset of cooler conditions during PZ 4. The MIS 6-MIS 5e transition here was similar to the MIS 2-MIS 1 transition at other Rocky Mountain sites. However, the Ziegler Reservoir pollen record contains evidence suggesting unexpected climatic trends at this site, including a warmer-than-expected MIS 5d and cooler-than-expected MIS 5b.

  9. Effects of 6-(4-chlorophenoxy)-tetrazolo[5,1-a]phthalazine on anticoagulation in mice and the inhibition of experimental thrombosis in rats.

    PubMed

    Yu, Hai-Ling; Zhang, Feng; Lan, Tian; Quan, Zhe-Shan

    2014-12-01

    : Thrombosis is a major complication that could be fatal in acute or chronic cardio-cerebral-vascular diseases. Therefore, the development of novel agents for anticlotting and the prevention of thrombosis and cardiovascular diseases are clinically significant. This study aimed to evaluate the anticoagulant and antithrombotic effects of 6-(4-chlorophenoxy)-tetrazolo[5,1-a]phthalazine (Q808), a new phthalazine tetrazole derivative. Bleeding time, clotting time, and serum calcium ion (Ca) concentration were assessed in mice, whereas arteriovenous thrombus weight and plasma prothrombin time were evaluated in rats, and platelets Ca influx was determined in rabbit. Daily oral administration of Q808 at 25, 50, or 100 mg/kg for 3 days significantly delayed bleeding time and clotting time in mice compared with controls. Q808 administration at 50 mg/kg significantly reduced experimental thrombus weight by 62.6% and delayed plasma prothrombin time by 58.7% in rats, whereas 50 and 100 mg/kg of Q808 daily significantly increased serum Ca concentration in mice. Q808 at 0.2, 0.4, and 0.8 mg/mL significantly inhibited thrombin-induced Ca influx in rabbit platelets. Our results suggest that Q808 at 25-200 mg/kg daily exerts anticoagulant and antithrombotic effects, and its mechanisms of action may involve both the intrinsic and extrinsic coagulation pathways that inhibit certain coagulation factors and platelet functions.

  10. Polyamine Resistance Is Increased by Mutations in a Nitrate Transporter Gene NRT1.3 (AtNPF6.4) in Arabidopsis thaliana

    PubMed Central

    Tong, Wurina; Imai, Akihiro; Tabata, Ryo; Shigenobu, Shuji; Yamaguchi, Katsushi; Yamada, Masashi; Hasebe, Mitsuyasu; Sawa, Shinichiro; Motose, Hiroyasu; Takahashi, Taku

    2016-01-01

    Polyamines are small basic compounds present in all living organisms and act in a variety of biological processes. However, the mechanism of polyamine sensing, signaling and response in relation to other metabolic pathways remains to be fully addressed in plant cells. As one approach, we isolated Arabidopsis mutants that show increased resistance to spermine in terms of chlorosis. We show here that two of the mutants have a point mutation in a nitrate transporter gene of the NRT1/PTR family (NPF), NRT1.3 (AtNPF6.4). These mutants also exhibit increased resistance to putrescine and spermidine while loss-of-function mutants of the two closest homologs of NRT1.3, root-specific NRT1.1 (AtNPF6.3) and petiole-specific NRT1.4 (AtNPF6.2), were shown to have a normal sensitivity to polyamines. When the GUS reporter gene was expressed under the control of the NRT1.3 promoter, GUS staining was observed in leaf mesophyll cells and stem cortex cells but not in the epidermis, suggesting that NRT1.3 specifically functions in parenchymal tissues. We further found that the aerial part of the mutant seedling has normal levels of polyamines but shows reduced uptake of norspermidine compared with the wild type. These results suggest that polyamine transport or metabolism is associated with nitrate transport in the parenchymal tissue of the shoot. PMID:27379127

  11. Repairing the Sickle Cell mutation. III. Effect of irradiation wavelength on the specificity and type of photoproduct formed by a 3′-terminal psoralen on a third strand directed to the mutant base pair

    PubMed Central

    Broitman, Steven L.; Amosova, Olga; Fresco, Jacques R.

    2003-01-01

    Using a psoralen delivery system mediated by a DNA third strand that binds selectively to linear target duplexes immediately downstream from the Sickle Cell β-globin gene mutation and the comparable wild-type β-globin gene sequence, the kinetics of formation and yield of psoralen monoadducts and crosslinks with pyrimidine residues at and near the mutant base pair site and its wild-type counterpart were determined. By exploiting irradiation specificities at 300, 365 and 419 nm, it was possible to evaluate the orientation equilibrium of 3′-linked intercalated psoralen and to develop conditions that lead to preferential formation of each type of photoproduct in both the mutant and wild-type sequences. This makes possible the preparation of each type of photoproduct for use as a substrate for DNA repair. In this way, the base pair change(s) that each generates can be established. PMID:12907707

  12. Repairing the Sickle Cell mutation. III. Effect of irradiation wavelength on the specificity and type of photoproduct formed by a 3'-terminal psoralen on a third strand directed to the mutant base pair.

    PubMed

    Broitman, Steven L; Amosova, Olga; Fresco, Jacques R

    2003-08-15

    Using a psoralen delivery system mediated by a DNA third strand that binds selectively to linear target duplexes immediately downstream from the Sickle Cell beta-globin gene mutation and the comparable wild-type beta-globin gene sequence, the kinetics of formation and yield of psoralen monoadducts and crosslinks with pyrimidine residues at and near the mutant base pair site and its wild-type counterpart were determined. By exploiting irradiation specificities at 300, 365 and 419 nm, it was possible to evaluate the orientation equilibrium of 3'-linked intercalated psoralen and to develop conditions that lead to preferential formation of each type of photoproduct in both the mutant and wild-type sequences. This makes possible the preparation of each type of photoproduct for use as a substrate for DNA repair. In this way, the base pair change(s) that each generates can be established.

  13. A new mineral species ferricoronadite, Pb[Mn6 4+(Fe3+, Mn3+)2]O16: mineralogical characterization, crystal chemistry and physical properties

    NASA Astrophysics Data System (ADS)

    Chukanov, Nikita V.; Aksenov, Sergey M.; Jančev, Simeon; Pekov, Igor V.; Göttlicher, Jörg; Polekhovsky, Yury S.; Rusakov, Vyacheslav S.; Nelyubina, Yuliya V.; Van, Konstantin V.

    2016-07-01

    A new mineral ferricoronadite with the simplified formula Pb(Mn6 4+Fe2 3+)O16 was discovered in the orogenetic zone related to the "Mixed Series" metamorphic complex near the Nežilovo village, Pelagonian massif, Republic of Macedonia. Associated minerals are franklinite, gahnite, hetaerolite, roméite, almeidaite, Mn-analogue of plumboferrite, zincohögbomite analogue with Fe3+ > Al, zincochromite, Zn-bearing talc, Zn-bearing muscovite, baryte, quartz and zircon. Ferricoronadite is a late hydrothermal mineral forming veinlets up to 8 mm thick in granular aggregate predominantly composed by zinc-dominant spinels. The new mineral is opaque, black, with brownish black streak. The luster is strong submetallic to metallic. The micro-indentation hardness is 819 kg/mm2. Distinct cleavage is observed on (100). Ferricoronadite is brittle, with uneven fracture. The density calculated from the empirical formula is 5.538 g/cm3. In reflected light, ferricoronadite is light gray. The reflectance values [ R max/ R min, % ( λ, nm)] are: 28.7/27.8 (470), 27.6/26.6 (546), 27.2/26.1 (589), 26.5/25.5 (650). The IR spectrum shows the absence of H2O and OH groups. According to the Mössbauer spectrum, all iron is trivalent. The Mn K-edge XANES spectroscopy shows that Mn is predominantly tetravalent, with subordinate Mn3+. The chemical composition is (wt%; electron microprobe, Mn apportioned between MnO2 and Mn2O3 based on the charge-balance requirement): BaO 5.16, PbO 24.50, ZnO 0.33, Al2O3 0.50, Mn2O3 9.90, Fe2O3 11.45, TiO2 4.19, MnO2 44.81, total 100.84. The empirical formula based on 8 cations Mn + Fe + Ti + Al + Zn pfu is Pb1.03Ba0.32(Mn 4.85 4+ Fe 1.35 3+ Mn 1.18 3+ Ti0.49Al0.09Zn0.04)Σ8.00O16. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is tetragonal, space group I4/ m, a = 9.9043(7), c = 2.8986(9) Å, V = 284.34(9) Å3, Z = 1. In ferricoronadite, double chains of edge-sharing (Mn, Fe, Ti)-centered octahedra are connected

  14. Numerical earthquake model of the 20 April 2015 southern Ryukyu subduction zone M6.4 event and its impact on seismic hazard assessment

    NASA Astrophysics Data System (ADS)

    Lee, Shiann-Jong

    2015-10-01

    The M6.4 earthquake that took place on the 20 April 2015 off the shore of eastern Taiwan was the largest event in the vicinity of Taiwan during 2015. The mainshock was located in the southern Ryukyu subduction zone, which is the interface between the Philippine Sea Plate and the Eurasian Plate. People in Taipei experienced strong ground shaking for more than 40 s, even though the epicenter was located more than 150 km away. In order to understand the origin of ground motions from this earthquake and how it caused such strong shaking in Taipei, a numerical earthquake model is analyzed, including models of source rupture and wave propagation. First, a joint source inversion was performed using teleseismic body wave and local ground motion data. Source inversion results show that a large slip occurred near the hypocenter, which rapidly released seismic energy in the first 2 s. Then, the rupture propagated toward the shallow fault plane. A large amount of seismic energy was released during this rupture stage that slipped for more than 8 s before the end of the rupture. The estimated stress drop is 2.48 MPa, which is consistent with values for subduction zone earthquakes. Forward simulation using this inverted source rupture model and a 3D seismic velocity model based on the spectral-element method was then performed. Results indicate that the strong ground motion in Taipei resulted from two factors: (1) the Taipei basin amplification effect and (2) the specific source radiation pattern. The results of this numerical earthquake model imply that future subduction zone events that occur in offshore eastern Taiwan are likely to cause relatively strong ground shaking in northern Taiwan, especially in the Taipei metropolitan area.

  15. Numerical earthquake model of the 20 April 2015 southern Ryukyu subduction zone M6.4 event and its impact on seismic hazard assessment

    NASA Astrophysics Data System (ADS)

    Lee, S. J.

    2015-12-01

    The M6.4 earthquake that took place on the 20th April 2015 off the shore of eastern Taiwan was the largest event that occurred in the vicinity of Taiwan during 2015. The mainshock located in the southern Ryukyu subduction zone, which is the interface between the Philippine Sea Plate and the Eurasian Plate. People in Taipei experienced strong ground shaking for more than 40 s, even though the epicenter was located more than 150 km away. In order to understand the origin of this earthquake and how it caused such strong shaking in Taipei, a numerical earthquake model is analyzed, including models of source rupture and wave propagation. First, a joint source inversion is performed using teleseismic body wave and local ground motion data. Source inversion results show that a large slip occurred near the hypocenter, which rapidly released seismic energy in the first 2 s. Then, the rupture propagated toward the shallow fault plane. A large amount of seismic energy was released during this rupture stage that slipped for more than 8 s before the end of the rupture. The estimated stress drop is 2.48 MPa, which is consistent with values for subduction zone earthquakes. Forward simulation using this inverted source rupture model based on the spectral-element method is then performed. Results indicate that the strong ground motion in Taipei resulted from two factors: (1) the Taipei basin amplification effect and (2) the specific source radiation pattern. The results of this numerical earthquake model imply that future subduction zone events that occur in offshore eastern Taiwan are likely to cause relatively strong ground shaking in northern Taiwan, especially in the Taipei metropolitan area.

  16. REDSHIFT 6.4 HOST GALAXIES OF 10{sup 8} SOLAR MASS BLACK HOLES: LOW STAR FORMATION RATE AND DYNAMICAL MASS

    SciTech Connect

    Willott, Chris J.; Omont, Alain; Bergeron, Jacqueline

    2013-06-10

    We present Atacama Large Millimeter Array observations of rest-frame far-infrared continuum and [C II] line emission in two z = 6.4 quasars with black hole masses of Almost-Equal-To 10{sup 8} M{sub Sun }. CFHQS J0210-0456 is detected in the continuum with a 1.2 mm flux of 120 {+-} 35 {mu}Jy, whereas CFHQS J2329-0301 is undetected at a similar noise level. J2329-0301 has a star formation rate limit of <40 M{sub Sun} yr{sup -1}, considerably below the typical value at all redshifts for this bolometric luminosity. Through comparison with hydro simulations, we speculate that this quasar is observed at a relatively rare phase where quasar feedback has effectively shut down star formation in the host galaxy. [C II] emission is also detected only in J0210-0456. The ratio of [C II] to far-infrared luminosity is similar to that of low-redshift galaxies of comparable luminosity, suggesting that the previous finding of an offset in the relationships between this ratio and far-infrared luminosity at low and high redshifts may be partially due to a selection effect due to the limited sensitivity of previous continuum data. The [C II] line of J0210-0456 is relatively narrow (FWHM = 189 {+-} 18 km s{sup -1}), indicating a dynamical mass substantially lower than expected from the local black hole-velocity dispersion correlation. The [C II] line is marginally resolved at 0.''7 resolution with the blue and red wings spatially offset by 0.''5 (3 kpc) and a smooth velocity gradient of 100 km s{sup -1} across a scale of 6 kpc, possibly due to the rotation of a galaxy-wide disk. These observations are consistent with the idea that stellar mass growth lags black hole accretion for quasars at this epoch with respect to more recent times.

  17. Thrust faulting and 3D ground deformation of the 3 July 2015 Mw 6.4 Pishan, China earthquake from Sentinel-1A radar interferometry

    NASA Astrophysics Data System (ADS)

    Sun, Jianbao; Shen, Zheng-Kang; Li, Tao; Chen, Jie

    2016-06-01

    Boosted by the launch of Sentinel-1A radar satellite from the European Space Agency (ESA), we now have the opportunity of fast, full and multiple coverage of the land based deformation field of earthquakes. Here we use the data to investigate a strong earthquake struck Pishan, western China on July 3, 2015. The earthquake fault is blind and no ground break features are found on-site, thus Synthetic Aperture Radar (SAR) data give full play to its technical advantage for the recovery of coseismic deformation field. By using the Sentinel-1A radar data in the Interferometric Wide Swath mode, we obtain 3 tracks of InSAR data over the struck region, and resolve the 3D ground deformation generated by the earthquake. Then the Line-of-Sight (LOS) InSAR data are inverted for the slip-distribution of the seismogenic fault. The final model shows that the earthquake is completely blind with pure-thrust motion. The maximum slip is 0.48 m at a depth of 7 km, consistent with the depth estimate from seismic reflection data. In particular, the inverted model is also compatible with a south-dipping fault ramp among a group of fault interfaces detected by the seismic reflection profile over the region. The seismic moment obtained equals to a Mw 6.4 earthquake. The Pishan earthquake ruptured the frontal part of the thrust ramps under the Slik anticline, and unloaded the coulomb stress of them. However, it may have loaded stress to the back-thrust above the thrust ramps by 1-4 bar, and promoted it for future failure. Moreover, the stress loading on the west side of the earthquake fault is much larger than that on the east side, indicating a higher risk for failure to the west of the Zepu fault.

  18. The 2012 August 11 MW 6.5, 6.4 Ahar-Varzghan earthquakes, NW Iran: aftershock sequence analysis and evidence for activity migration

    NASA Astrophysics Data System (ADS)

    Rezapour, Mehdi

    2016-02-01

    The Ahar-Varzghan doublet earthquakes with magnitudes MW 6.5 and 6.4 occurred on 2012 August 11 in northwest Iran and were followed by many aftershocks. In this paper, we analyse ˜5 months of aftershocks of these events. The Ahar-Varzghan earthquakes occurred along complex faults and provide a new constraint on the earthquake hazard in northwest Iran. The general pattern of relocated aftershocks defines a complex seismic zone covering an area of approximately 25 × 10 km2. The Ahar-Varzghan aftershock sequence shows a secondary activity which started on November 7, approximately 3 months after the main shocks, with a significant increase in activity, regarding both number of events and their magnitude. This stage was characterized by a seismic zone that propagated to the west of the main shocks. The catalogue of aftershocks for the doublet earthquake has a magnitude completeness of Mc 2.0. A below-average b-value for the Ahar-Varzghan sequence indicates a structural heterogeneity in the fault plane and the compressive stress state of the region. Relocated aftershocks occupy a broad zone clustering east-west with near-vertical dip which we interpret as the fault plane of the first of the doublet main shocks (MW 6.5). The dominant depth range of the aftershocks is from 3 to about 20 km, and the focal depths decrease toward the western part of the fault. The aftershock activity has its highest concentration in the eastern and middle parts of the active fault, and tapers off toward the western part of the active fault segment, indicating mainly a unilateral rupture toward west.

  19. Stochastic finite-fault simulation of ground motion from the August 11, 2012, M w 6.4 Ahar earthquake, northwestern Iran

    NASA Astrophysics Data System (ADS)

    Heidari, Reza

    2016-04-01

    In this study, the 11 August 2012 M w 6.4 Ahar earthquake is investigated using the ground motion simulation based on the stochastic finite-fault model. The earthquake occurred in northwestern Iran and causing extensive damage in the city of Ahar and surrounding areas. A network consisting of 58 acceleration stations recorded the earthquake within 8-217 km of the epicenter. Strong ground motion records from six significant well-recorded stations close to the epicenter have been simulated. These stations are installed in areas which experienced significant structural damage and humanity loss during the earthquake. The simulation is carried out using the dynamic corner frequency model of rupture propagation by extended fault simulation program (EXSIM). For this purpose, the propagation features of shear-wave including {Q}_s value, kappa value {k}_0 , and soil amplification coefficients at each site are required. The kappa values are obtained from the slope of smoothed amplitude of Fourier spectra of acceleration at higher frequencies. The determined kappa values for vertical and horizontal components are 0.02 and 0.05 s, respectively. Furthermore, an anelastic attenuation parameter is derived from energy decay of a seismic wave by using continuous wavelet transform (CWT) for each station. The average frequency-dependent relation estimated for the region is Q=(122± 38){f}^{(1.40± 0.16)}. Moreover, the horizontal to vertical spectral ratio H/V is applied to estimate the site effects at stations. Spectral analysis of the data indicates that the best match between the observed and simulated spectra occurs for an average stress drop of 70 bars. Finally, the simulated and observed results are compared with pseudo acceleration spectra and peak ground motions. The comparison of time series spectra shows good agreement between the observed and the simulated waveforms at frequencies of engineering interest.

  20. Effect of PpIX photoproducts formation on pO2 measurement by time-resolved delayed fluorescence spectroscopy of PpIX in solution and in vivo.

    PubMed

    Huntosova, Veronika; Gerelli, Emmanuel; Zellweger, Matthieu; Wagnières, Georges

    2016-11-01

    The measurement of Protoporphyrin IX delayed fluorescence lifetime is a minimally invasive method for monitoring the levels of oxygen in cells and tissues. The excitation of Protoporphyrin IX during this measurement can lead to the formation of photoproducts in vitro and in vivo. The influence of their luminescence on the measured Protoporphyrin IX delayed fluorescence lifetimes was studied in solution and in vivo on the Chick's chorioallantoic membrane (CAM) model under various oxygen enriched air conditions (0mmHg, 37mmHg and 155mmHg). The presence of photoproducts disturbs such measurements since the delayed fluorescence emission of some of them spectrally overlaps with that of Protoporphyrin IX. One possible way to avoid this obstacle is to detect Protoporphyrin IX's delayed fluorescence lifetime in a very specific spectral range (620-640nm). Another possibility is to excite Protoporphyrin IX with light doses much lower than 10J/cm(2), quite possibly as low as a fraction 1J/cm(2) at 405nm. This leads to an increased accuracy of pO2 detection. Furthermore, this method allows combination of diagnosis and therapy in one step. This helps to improve detection systems and real-time identification of tissue respiration, which is tuned for the detection of PpIX luminescence and not its photoproducts.

  1. Pressurized liquid extraction-gas chromatography-mass spectrometry for confirming the photo-induced generation of dioxin-like derivatives and other cosmetic preservative photoproducts on artificial skin.

    PubMed

    Alvarez-Rivera, Gerardo; Llompart, Maria; Garcia-Jares, Carmen; Lores, Marta

    2016-04-01

    The stability and photochemical transformations of cosmetic preservatives in topical applications exposed to UV-light is a serious but poorly understood problem. In this study, a high throughput extraction and selective method based on pressurized liquid extraction (PLE) coupled to gas chromatography-mass spectrometry (GC-MS) was validated and applied to investigate the photochemical transformation of the antioxidant butylated hydroxytoluene (BHT), as well as the antimicrobials triclosan (TCS) and phenyl benzoate (PhBz) in an artificial skin model. Two sets of photodegradation experiments were performed: (i) UV-Irradiation (8W, 254nm) of artificial skin directly spiked with the target preservatives, and (ii) UV-irradiation of artificial skin after the application of a cosmetic cream fortified with the target compounds. After irradiation, PLE was used to isolate the target preservatives and their transformation products. The follow-up of the photodegradation kinetics of the parent preservatives, the identification of the arising by-products, and the monitorization of their kinetic profiles was performed by GC-MS. The photochemical transformation of triclosan into 2,8-dichloro-dibenzo-p-dioxin (2,8-DCDD) and other dioxin-like photoproducts has been confirmed in this work. Furthermore, seven BHT photoproducts, and three benzophenones as PhBz by-products, have been also identified. These findings reveal the first evidences of cosmetic ingredients phototransformation into unwanted photoproducts on an artificial skin model.

  2. Relocation of the Mw 6.4 July 1, 2009 earthquake to the south of Crete and modeling of its associated small tsunami

    NASA Astrophysics Data System (ADS)

    Bocchini, Gian Maria; Papadopoulos, Gerassimos A.; Novikova, Tatiana; Karastathis, Vassilis K.; Mouzakiotis, Aggelos; Voulgaris, Nikolaos

    2016-04-01

    On July 1, 2009 (09:30 UTC) a Mw6.4 earthquake ruptured south of Crete Island triggering a small tsunami. Eyewitness reported the tsunami from Myrtos and Arvi Port, in the SE coast of Crete, and in Chrisi islet. In Arvi 4 or 5 wave arrivals were reported after a withdrawal of the sea of about 1 m. The sea disturbance lasted for about 1 h. The earthquake occurred as the result of the subduction of the oceanic African Plate beneath the continental Eurasian Plate along the Hellenic Subduction Zone (HSZ). South of Crete the Nubia-Aegean convergence rate (~3.5 cm/yr) is partially accommodated by low-angle (~20-25°) thrust faults at 20-40km depths and by steeper (>30°) reverse-faults at shallower depths. The area of interest has been struck by large magnitude earthquakes in historical times that in some cases triggered damaging tsunamis (e.g AD 1303). Routine earthquake locations performed by NOA do not provide good quality hypocenters for the area under investigation given the poor azimuthal coverage and the low density of the seismic stations. The 2009 earthquake, given its tsunamigenic nature, has been identified as a key event to study the central segment of the HSZ. We performed the relocation of the 2009 mainshock along with the seismicity of the area (ML>=3, period 2008-2015) using the NLLoc algorithm and testing several 1D velocity models available for the area and a 2D velocity model obtained from a published N-S seismic refraction profile across Crete. The hypocenters obtained from NLLoc have been subsequently relocated with HypoDD algorithm using catalog phase data. The results from the various relocation procedures showed a shallow hypocentral depth (12-17km) of the 2009 event and its likely intraplate nature. A set of hypocentral solutions were selected on the basis of minimum RMS and smaller errors with the aim to perform tsunami simulations with varying source parameters. Two different fault dips were used to discriminate between the intraplate (dip 32

  3. Study of Geomagnetic Anomalies Related to Earthquakes at Pisco Peru 2007 (M=8.0) and at Taiwan 2009 (M= 6.4) (Invited)

    NASA Astrophysics Data System (ADS)

    Yumoto, K.; Takla, E.; Ishitsuka, J.; Rosales, D.; Dutra, S. L.; Liu, J. G.; Kakinami, Y.; Uozumi, T.; Abe, S.

    2010-12-01

    The Space Environment Research Center (SERC), Kyushu University deployed the MAGnetic Data Acqusition System (MAGDAS) at 53 stations along the 210- and 96-degree magnetic meridians (MM) and the magnetic Dip equator, and three FM-CW radars along the 210-degree MM during the International Heliophysical Year (IHY) period of 2005-2009 (see http://magdas.serc.kyushu-u.ac.jp/ and http://magdas2.serc.kyushu-u.ac.jp/). By analyzing these new MAGDAS data, we can perform a real-time monitoring for understanding the plasma and electromagnetic environment changes in geospace and lithosphere. In the present paper, we will introduce geomagnetic anomalies associated with larger earthquakes (EQs), observed at the MAGDAS stations. The first event is the Pisco earthquake (M=8.0) on August 15, 2007, which was the largest shallow earthquake and affected the coastal area south of Lima for 250 years. This occurred at the boundary between the Nazca and South American tectonic plates. Geomagnetic data from the MAGDAS Ancon (ANC; about 180 km from the epicenter), the INTERMAGNET Huancayo (HUA;about 190 km from the epicenter) and the MAGDAS Eusebio (EUS; about 39°east from ANC) stations were analyzed to clarify if there is a relation between the geomagnetic variations and the tectonic activities at Peru during 2007. Our results indicate both long- (several months) and short-term (daily) anomalous geomagnetic variations (H and Z components) in relation with these seismic activities. In addition, there were anomalous signals of Pc 3 polarization (Z/H) a few months before the onset of seismic activities. The second event is the Taiwan earthquake of M=6.4 on the Richter scale, which occurred at depth ≈ 45 km, on 19th of December 2009. The epicenter was located about 20 Km away from our MAGDAS Hualien (HLN) station. The MAGDAS Amami-ohshima (AMA) station in Japan was used as a remote reference station. The geomagnetic components (H, D and Z) at the HLN station showed baseline fluctuations

  4. Whole genome expression profiling shows that BRG1 transcriptionally regulates UV inducible genes and other novel targets in human cells.

    PubMed

    Zhang, Ling; Nemzow, Leah; Chen, Hua; Hu, Jennifer J; Gong, Feng

    2014-01-01

    UV irradiation is known to cause cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs), and plays a large role in the development of cancer. Tumor suppression, through DNA repair and proper cell cycle regulation, is an integral factor in maintaining healthy cells and preventing development of cancer. Transcriptional regulation of the genes involved in the various tumor suppression pathways is essential for them to be expressed when needed and to function properly. BRG1, an ATPase catalytic subunit of the SWI/SNF chromatin remodeling complex, has been identified as a tumor suppressor protein, as it has been shown to play a role in Nucleotide Excision Repair (NER) of CPDs, suppress apoptosis, and restore checkpoint deficiency, in response to UV exposure. Although BRG1 has been shown to regulate transcription of some genes that are instrumental in proper DNA damage repair and cell cycle maintenance in response to UV, its role in transcriptional regulation of the whole genome in response to UV has not yet been elucidated. With whole genome expression profiling in SW13 cells, we show that upon UV induction, BRG1 regulates transcriptional expression of many genes involved in cell stress response. Additionally, our results also highlight BRG1's general role as a master regulator of the genome, as it transcriptionally regulates approximately 4.8% of the human genome, including expression of genes involved in many pathways. RT-PCR and ChIP were used to validate our genome expression analysis. Importantly, our study identifies several novel transcriptional targets of BRG1, such as ATF3. Thus, BRG1 has a larger impact on human genome expression than previously thought, and our studies will provide inroads for future analysis of BRG1's role in gene regulation.

  5. Signal enhancement for gene detection based on a redox reaction of [Fe(CN)(6)](4-) mediated by ferrocene at the terminal of a peptide nucleic acid as a probe with hybridization-amenable conformational flexibility.

    PubMed

    Aoki, Hiroshi; Tao, Hiroaki

    2008-07-01

    Electrochemically enhanced DNA detection was demonstrated by utilizing the couple of a synthesized ferrocene-terminated peptide nucleic acid (PNA) with a cysteine anchor and a sacrificial electron donor [Fe(CN)(6)](4-). DNA detection sensors were prepared by modifying a gold electrode surface with a mixed monolayer of the probe PNA and 11-hydroxy-1-undecanethiol (11-HUT), protecting [Fe(CN)(6)](4-) from any unexpected redox reaction. Before hybridization, the terminal ferrocene moiety of the probe was subject to a redox reaction due to the flexible probe structure and, in the presence of [Fe(CN)(6)](4-), the observed current was amplified based on regeneration of the ferrocene moiety. Hybridization decreased the redox current of the ferrocene. This occurred because hybridization rigidified the probe structure: the ferrocene moiety was then removed from the electrode surface, and the redox reaction of [Fe(CN)(6)](4-) was again prevented. The change in the anodic current before and after hybridization was enhanced 1.75-fold by using the electron donor [Fe(CN)(6)](4-). Sequence-specific detection of the complementary target DNA was also demonstrated.

  6. Nucleotide excision repair and photolyase repair of UV photoproducts in nucleosomes: assessing the existence of nucleosome and non-nucleosome rDNA chromatin in vivo.

    PubMed

    Tremblay, Maxime; Toussaint, Martin; D'Amours, Annie; Conconi, Antonio

    2009-02-01

    The genome is organized into nuclear domains, which create microenvironments that favor distinct chromatin structures and functions (e.g., highly repetitive sequences, centromeres, telomeres, noncoding sequences, inactive genes, RNA polymerase II and III transcribed genes, and the nucleolus). Correlations have been drawn between gene silencing and proximity to a heterochromatic compartment. At the other end of the scale are ribosomal genes, which are transcribed at a very high rate by RNA polymerase I (~60% of total transcription), have a loose chromatin structure, and are clustered in the nucleolus. The rDNA sequences have 2 distinct structures: active rRNA genes, which have no nucleosomes; and inactive rRNA genes, which have nucleosomes. Like DNA transcription and replication, DNA repair is modulated by the structure of chromatin, and the kinetics of DNA repair vary among the nuclear domains. Although research on DNA repair in all chromosomal contexts is important to understand the mechanisms of genome maintenance, this review focuses on nucleotide excision repair and photolyase repair of UV photoproducts in the first-order packing of DNA in chromatin: the nucleosome. In addition, it summarizes the studies that have demonstrated the existence of the 2 rDNA chromatins, and the way this feature of the rDNA locus allows for direct comparison of DNA repair in 2 very different structures: nucleosome and non-nucleosome DNA.

  7. Determination of the Hyperon Induced Polarization and Polarization-Transfer Coefficients for Quasi-Free Hyperon Photoproduction off the Bound Neutron

    NASA Astrophysics Data System (ADS)

    Gleason, Colin; CLAS Collaboration

    2016-09-01

    Measurement of the excited nucleon (N*) spectrum provides key information on the relevant degrees of freedom within the nucleon and requires an extensive set of experimental observables over a broad kinematic range for many nuclear reactions. Polarization observables from kaon-hyperon (KY) channels are needed as many resonances predicted by quark models, but not observed in πN channels, are expected to couple strongly to KY channels. While in the last decade data has been published for KY off the proton, data off the neutron are scarce. In this talk we will show preliminary results for P, CX, and CZ for the reaction γd ->K0 Λ (p) for Eγ between 0.9-2.6 GeV and cosθK0CM between -0.9-1. The data was collected in experiment E06-103 (g13) with the CLAS detector at Thomas Jefferson National Accelerator Facility using a circularly polarized photon beam and an unpolarized LD2 target. We will discuss the effect of neutron binding on the observables and the comparison of our results with theoretical predictions. Our study is part of a larger effort by the g13 group to provide cross-sections and polarization observables for meson photoproduction off the neutron and is expected to have a large impact on the N* research. NSF PHY-125782.

  8. Charmonium and e(+)e(-) pair photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at [Formula: see text].

    PubMed

    Abbas, E; Abelev, B; Adam, J; Adamová, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agocs, A G; Agostinelli, A; Ahammed, Z; Ahmad, N; Ahmad Masoodi, A; Ahmed, I; Ahn, S A; Ahn, S U; Aimo, I; Ajaz, M; Akindinov, A; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Almaráz Aviña, E; Alme, J; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Anson, C; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arbor, N; Arcelli, S; Arend, A; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Asryan, A; Augustinus, A; Averbeck, R; Awes, T C; Äystö, J; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bailhache, R; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Bán, J; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batyunya, B; Batzing, P C; Baumann, C; Bearden, I G; Beck, H; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Bencedi, G; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Bergognon, A A E; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhati, A K; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Bjelogrlic, S; Blanco, F; Blanco, F; Blau, D; Blume, C; Boccioli, M; Böttger, S; Bogdanov, A; Bøggild, H; Bogolyubsky, M; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Bossú, F; Botje, M; Botta, E; Braidot, E; Braun-Munzinger, P; Bregant, M; Breitner, T; Broker, T A; Browning, T A; Broz, M; Brun, R; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Caffarri, D; Cai, X; Caines, H; Calvo Villar, E; Camerini, P; Canoa Roman, V; Cara Romeo, G; Carena, W; Carena, F; Carlin Filho, N; Carminati, F; Casanova Díaz, A; Castillo Castellanos, J; Castillo Hernandez, J F; Casula, E A R; Catanescu, V; Cavicchioli, C; Ceballos Sanchez, C; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Conesa Balbastre, G; Conesa Del Valle, Z; Connors, M E; Contin, G; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortés Maldonado, I; Cosentino, M R; Costa, F; Cotallo, M E; Crescio, E; Crochet, P; Cruz Alaniz, E; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Dainese, A; Dang, R; Danu, A; Das, K; Das, I; Das, S; Das, D; Dash, S; Dash, A; De, S; de Barros, G O V; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; Delagrange, H; Deloff, A; De Marco, N; Dénes, E; De Pasquale, S; Deppman, A; D Erasmo, G; de Rooij, R; Diaz Corchero, M A; Di Bari, D; Dietel, T; Di Giglio, C; Di Liberto, S; Di Mauro, A; Di Nezza, P; Divià, R; Djuvsland, Ø; Dobrin, A; Dobrowolski, T; Dönigus, B; Dordic, O; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; Elia, D; Emschermann, D; Engel, H; Erazmus, B; Erdal, H A; Eschweiler, D; Espagnon, B; Estienne, M; Esumi, S; Evans, D; Evdokimov, S; Eyyubova, G; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Fenton-Olsen, B; Feofilov, G; Fernández Téllez, A; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A; Gallio, M; Gangadharan, D R; Ganoti, P; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Garishvili, I; Gerhard, J; Germain, M; Geuna, C; Gheata, M; Gheata, A; Ghidini, B; Ghosh, P; Gianotti, P; Giubellino, P; Gladysz-Dziadus, E; Glässel, P; Gomez, R; Ferreiro, E G; González-Trueba, L H; González-Zamora, P; Gorbunov, S; Goswami, A; Gotovac, S; Graczykowski, L K; Grajcarek, R; Grelli, A; Grigoras, C; Grigoras, A; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Gros, P; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gunji, T; Gupta, A; Gupta, R; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Han, B H; Hanratty, L D; Hansen, A; Harmanová-Tóthová, Z; Harris, J W; Hartig, M; Harton, A; Hatzifotiadou, D; Hayashi, S; Hayrapetyan, A; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Herrmann, N; Hess, B A; Hetland, K F; Hicks, B; Hippolyte, B; Hori, Y; Hristov, P; Hřivnáčová, I; Huang, M; Humanic, T J; Hwang, D S; Ichou, R; Ilkaev, R; Ilkiv, I; Inaba, M; Incani, E; Innocenti, G M; Innocenti, P G; Ippolitov, M; Irfan, M; Ivan, C; Ivanov, M; Ivanov, A; Ivanov, V; Ivanytskyi, O; Jachołkowski, A; Jacobs, P M; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, S; Jha, D M; Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kaidalov, A B; Kalcher, S; Kaliňák, P; Kalliokoski, T; Kalweit, A; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kazantsev, A; Kebschull, U; Keidel, R; Ketzer, B; Khan, M M; Khan, P; Khan, S A; Khan, K H; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, M; Kim, T; Kim, B; Kim, S; Kim, M; Kim, D J; Kim, J S; Kim, J H; Kim, D W; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Klay, J L; Klein, J; Klein-Bösing, C; Kliemant, M; Kluge, A; Knichel, M L; Knospe, A G; Köhler, M K; Kollegger, T; Kolojvari, A; Kompaniets, M; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kramer, F; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Krus, M; Kryshen, E; Krzewicki, M; Kucera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, V; Kushpil, S; Kvaerno, H; Kweon, M J; Kwon, Y; Ladrón de Guevara, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; La Pointe, S L; Lara, C; Lardeux, A; La Rocca, P; Lea, R; Lechman, M; Lee, S C; Lee, G R; Legrand, I; Lehnert, J; Lemmon, R C; Lenhardt, M; Lenti, V; León, H; Leoncino, M; León Monzón, I; Lévai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Lodato, D F; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Loo, K K; Lopez, X; López Torres, E; Løvhøiden, G; Lu, X-G; Luettig, P; Lunardon, M; Luo, J; Luparello, G; Luzzi, C; Ma, R; Ma, K; Madagodahettige-Don, D M; Maevskaya, A; Mager, M; Mahapatra, D P; Maire, A; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Mangotra, L; Manko, V; Manso, F; Manzari, V; Mao, Y; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Marín, A; Markert, C; Marquard, M; Martashvili, I; Martin, N A; Martinengo, P; Martínez, M I; Martínez García, G; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matyja, A; Mayer, C; Mazer, J; Mazumder, R; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitu, C; Mizuno, S; Mlynarz, J; Mohanty, B; Molnar, L; Montaño Zetina, L; Monteno, M; Montes, E; Moon, T; Morando, M; Moreira De Godoy, D A; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Muhuri, S; Mukherjee, M; Müller, H; Munhoz, M G; Murray, S; Musa, L; Musinsky, J; Nandi, B K; Nania, R; Nappi, E; Nattrass, C; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Niida, T; Nikolaev, S; Nikolic, V; Nikulin, S; Nikulin, V; Nilsen, B S; Nilsson, M S; Noferini, F; Nomokonov, P; Nooren, G; Nyanin, A; Nyatha, A; Nygaard, C; Nystrand, J; Ochirov, A; Oeschler, H; Oh, S; Oh, S K; Oleniacz, J; Oliveira Da Silva, A C; Onderwaater, J; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Ostrowski, P; Otwinowski, J; Oyama, K; Ozawa, K; Pachmayer, Y; Pachr, M; Padilla, F; Pagano, P; Paić, G; Painke, F; Pajares, C; Pal, S K; Palaha, A; Palmeri, A; Papikyan, V; Pappalardo, G S; Park, W J; Passfeld, A; Patalakha, D I; Paticchio, V; Paul, B; Pavlinov, A; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Pérez Lara, C E; Perrino, D; Peryt, W; Pesci, A; Pestov, Y; Petráček, V; Petran, M; Petris, M; Petrov, P; Petrovici, M; Petta, C; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Pitz, N; Piyarathna, D B; Planinic, M; Płoskoń, M; Pluta, J; Pocheptsov, T; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polák, K; Polichtchouk, B; Poljak, N; Pop, A; Porteboeuf-Houssais, S; Pospíšil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Rademakers, A; Räihä, T S; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, S; Raniwala, R; Räsänen, S S; Rascanu, B T; Rathee, D; Rauch, W; Rauf, A W; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J-P; Reygers, K; Riccati, L; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rivetti, A; Rodríguez Cahuantzi, M; Rodriguez Manso, A; Røed, K; Rogochaya, E; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Rosnet, P; Rossegger, S; Rossi, A; Roy, P; Roy, C; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Rybicki, A; Sadovsky, S; Šafařík, K; Sahoo, R; Sahu, P K; Saini, J; Sakaguchi, H; Sakai, S; Sakata, D; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Šándor, L; Sandoval, A; Sano, M; Santagati, G; Santoro, R; Sarkamo, J; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, H R; Schmidt, C; Schuchmann, S; Schukraft, J; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Scott, P A; Segato, G; Selyuzhenkov, I; Senyukov, S; Seo, J; Serci, S; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Sharma, S; Sharma, N; Rohni, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Sicking, E; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, T; Sinha, B C; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R J M; Søgaard, C; Soltz, R; Song, M; Song, J; Soos, C; Soramel, F; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vásquez, M A; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Šumbera, M; Susa, T; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szymański, M; Takahashi, J; Tangaro, M A; Tapia Takaki, J D; Tarantola Peloni, A; Tarazona Martinez, A; Tauro, A; Tejeda Muñoz, G; Telesca, A; Ter Minasyan, A; Terrevoli, C; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Tlusty, D; Toia, A; Torii, H; Toscano, L; Trubnikov, V; Truesdale, D; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ulery, J; Ullaland, K; Ulrich, J; Uras, A; Urciuoli, G M; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Vallero, S; Vande Vyvre, P; Van Hoorne, J W; van Leeuwen, M; Vannucci, L; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Venaruzzo, M; Vercellin, E; Vergara, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, Y; Vinogradov, L; Vinogradov, A; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, S; Voloshin, K; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, V; Wagner, B; Wan, R; Wang, Y; Wang, Y; Wang, M; Watanabe, K; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Williams, M C S; Windelband, B; Yaldo, C G; Yamaguchi, Y; Yang, S; Yang, P; Yang, H; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I-K; Yoon, J; Yuan, X; Yushmanov, I; Zaccolo, V; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zgura, I S; Zhalov, M; Zhang, Y; Zhang, H; Zhang, X; Zhou, D; Zhou, Y; Zhou, F; Zhu, H; Zhu, J; Zhu, X; Zhu, J; Zichichi, A; Zimmermann, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M; Zyzak, M

    The ALICE Collaboration at the LHC has measured the J/ψ and ψ' photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at [Formula: see text]. The charmonium is identified via its leptonic decay for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 23 μb(-1). The cross section for coherent and incoherent J/ψ production in the rapidity interval -0.9

  9. Photodegradation behaviour of sethoxydim and its comercial formulation Poast(®) under environmentally-relevant conditions in aqueous media. Study of photoproducts and their toxicity.

    PubMed

    Sevilla-Morán, Beatriz; Calvo, Luisa; López-Goti, Carmen; Alonso-Prados, José L; Sandín-España, Pilar

    2017-02-01

    Photolysis is an important route for the abiotic degradation of many pesticides. However, the knowledge of the photolytic behaviour of these compounds and their commercial formulations under environmentally-relevant conditions are limited. The present study investigated the importance of photochemical processes on the persistence and fate of the herbicide sethoxydim and its commercial formulation Poast(®) in aqueous media. Moreover, the effect of important natural water substances (nitrate, calcium, and ferric ions) on the photolysis of the herbicide was also studied. The results showed that additives existing in the commercial formulation Poast(®) accelerated the rate of photolysis of sethoxydim by a factor of 3. On the contrary, the presence of nitrate and calcium ions had no effect on the photodegradation rate while ferric ions resulted in an important decrease in the half-life of sethoxydim possibly due to the formation of a complex. Different transformation products were identified in the course of sethoxydim irradiation and the effect of experimental conditions on their concentrations was investigated. Finally, Microtox(®) test revealed that aqueous solutions of sethoxydim photoproducts increased the toxicity to the bacteria Vibrio fischeri.

  10. Crystal structures of ethyl 6-(4-methyl­phen­yl)-4-oxo-4H-chromene-2-carboxyl­ate and ethyl 6-(4-fluoro­phen­yl)-4-oxo-4H-chromene-2-carboxyl­ate

    PubMed Central

    Gomes, Ligia R.; Low, John Nicolson; Fernandes, Carlos; Gaspar, Alexandra; Borges, Fernanda

    2016-01-01

    The crystal structures of two chromone derivatives, viz. ethyl 6-(4-methyl­phen­yl)-4-oxo-4H-chromene-2-carboxyl­ate, C19H16O4, (1), and ethyl 6-(4-fluoro­phen­yl)-4-oxo-4H-chromene-2-carboxyl­ate C18H13FO4, (2), have been determined: (1) crystallizes with two mol­ecules in the asymmetric unit. A comparison of the dihedral angles beween the mean planes of the central chromone core with those of the substituents, an ethyl ester moiety at the 2-position and a para-substituted phenyl ring at the 6-position shows that each mol­ecule differs significantly from the others, even the two independent mol­ecules (a and b) of (1). In all three mol­ecules, the carbonyl groups of the chromone and the carboxyl­ate are trans-related. The supra­molecular structure of (1) involves only weak C—H⋯π inter­actions between H atoms of the substituent phenyl group and the phenyl group, which link mol­ecules into a chain of alternating mol­ecules a and b, and weak π–π stacking inter­actions between the chromone units. The packing in (2) involves C—H⋯O inter­actions, which form a network of two inter­secting ladders involving the carbonyl atom of the carboxyl­ate group as the acceptor for H atoms at the 7-position of the chromone ring and from an ortho-H atom of the exocyclic benzene ring. The carbonyl atom of the chromone acts as an acceptor from a meta-H atom of the exocyclic benzene ring. π–π inter­actions stack the mol­ecules by unit translation along the a axis. PMID:26870574

  11. Kinetic study of the oxidation of [Fe(CN) 6] 4- by [Co(NH 3) 4pzCO 2] 2+ and SO82- in the presence of the tripodal ligand Tren Aminopropil

    NASA Astrophysics Data System (ADS)

    García-España, E.; Sornosa-Ten, A.; Albelda, M. T.; Sánchez, F.; Marchena, M.

    2011-03-01

    Oxidations (electron transfers) of [Fe(CN) 6] 4- by [Co(NH 3) 4pzCO 2] 2+ and SO82- have been studied in solutions containing the receptor N,N',N″-(aminopropil)-tris (2-aminoetil) amina [Tren Aminopropil, TAL], which can incorporate [Fe(CN) 6] 4- and SO82- but not the cobalt complex. The results can be explained using the Brönsted equation that allows to obtain the binding constant of the transition state, a parameter that the Pseudophase Model cannot provide.

  12. Determination of trace mercury by solid substrate-room temperature phosphorimetry quenching method based on catalytic effect of Hg2+ on formation of the ion association complex [Sn(XO)6]4+.[(Fin)4].

    PubMed

    Liu, Jia-Ming; Wu, Ruo-Hong; Li, De-Chang; Zhou, Ping; Zheng, Min-Min; Zeng, Xiao-Yi; Liu, Dong-Xia; Huang, Xiao-Mei; Zhu, Guo-Hui

    2006-09-01

    A new method for the determination of trace mercury by solid substrate-room temperature phosphorimetry (SS-RTP) quenching method has been established. In glycine-HCl buffer solution, xylenol orange (XO) can react with Sn4+ to form the complex [Sn(XO)6]4+. [Sn(XO)6]4+ can interact with Fin- (fluorescein anion) to form the ion associate [Sn(XO)6]4+.[(Fin)4]-, which can emit strong and stable room temperature phosphorescence (RTP) on polyamide membrane (PAM). Hg2+ can catalyze H2O2 oxidizing the ion association complex [Sn(XO)6]4+.[(Fin)4]-, which causes the RTP to quench. The DeltaIp value is directly proportional to the concentration of Hg2+ in the range of 0.016-1.6 fg spot(-1) (corresponding concentration: 0.040-4.0 pg ml(-1), 0.40 microl spot(-1)), and the regression equation of working cure is DeltaIp=10.03+83.15 m Hg2+ (fg spot(-1)), (r=0.9987, n=6) and the detection limit (LD) is 3.6 ag spot(-1)(corresponding concentration: 9.0 x 10(-15) g ml(-1), the sample volume: 0.4 microl). This simple, rapid, accurate method is of high selectivity and good repeatability, and it has been successfully applied to the determination of trace mercury in real samples. The reaction mechanism for catalyzing H2O2 oxidizing the ion association complex ([Sn(XO)6]4+.[(Fin)4]-) SS-RTP quenching method to determine trace mercury is also discussed.

  13. K*(892)0Λ and K+Σ*(1385)- Photoproduction on the Deuteron

    SciTech Connect

    Mattione, Paul

    2011-05-01

    Thirteen N* states have been well-established according to the Particle Data Group, but some relativized quark models predict that many more N* resonances exist. Diquark models predict that the N* spectrum is limited by a correlated quark-pair in the nucleon, but there is strong evidence for the existence of the N 3/2+(1900)** resonance, which is absent in diquark models. Measuring the spectrum of N* states will provide valuable information on the relevant degrees of freedom within the nucleons. Most of the experimental searches for the N* states have been conducted in the π N channel. Some models of baryon decays predict that most of the unobserved N* states couple somewhat weakly to the π N channel, and that some couple non-negligibly to the KY, K*Y, and KY* channels. Measurements of the cross sections and polarization observables of strangeness photoproduction reactions can provide additional information on the spectrum of N* states. These measurements can be used in coupled-channel partial-wave analyses that can provide simultaneous constraints on the N* resonance parameters from several channels. These analyses can also take into account hadronic rescattering, which is predicted to have a large effect on the measured cross sections. However, to determine the isospin decomposition of the photo-transition amplitudes to these channels, photoproduction measurements are necessary on both the proton and the neutron. Measurements of the differential cross sections of the γn\\rightarrow K*(892)0Λ and γn→ K+Σ*(1385)- reactions have been performed using data from the Jefferson Lab Hall B CLAS g13 experiment. No experimental cross section data have yet been published on the γ n\\rightarrow K*(892)0Λ reaction, and the only published cross section data on

  14. Photoproduction of the f1(1285) meson

    Sc