The Effects of addition of carbon dioxide and water vapor on the dynamic behavior of spherically expanding hydrogen/air premixed flames

Katsumi, Toshiyuki; Yoshida, Yasuhito*; Nakagawa, Ryo*; Yazawa, Shinya*; Kumada, Masashi*; Sato, Daisuke*; Thwe Thwe, A.; Chaumeix, N.*; Kadowaki, Satoshi

Journal of Thermal Science and Technology (Internet), 16(2), p.21-00044_1 - 21-00044_13, 2021/00

https://doi.org/10.1299/jtst.2021jtst0026

The effects of addition of CO and water vapor on characteristics of dynamic behavior of hydrogen/air premixed flames were elucidated experimentally. By Schlieren photography, wrinkles on the flame surface were clearly observed in low equivalence ratios. The propagation velocity increased monotonically as the flame radius became larger and flame acceleration was found. Increasing the addition of inert gas, the propagation velocity decreased, especially in the case of CO addition. Moreover, the Markstein length and the wrinkling factor decreased. This indicated that the addition of Co or HO promoted the unstable motion of hydrogen flames, which could be due to the enhancement of the diffusive-thermal effect. Based on the characteristics of dynamic behavior of hydrogen flames, the parameters used in the mathematical model on propagation velocity including flame acceleration was obtained, and then the flame propagation velocity under various conditions was predicted.

Event structure and double helicity asymmetry in jet production from polarized collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07

https://doi.org/10.1103/PhysRevD.84.012006

We report on the event structure and double helicity asymmetry () of jet production in longitudinally polarized collisions at = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured = -0.0014 0.0037 at the lowest bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various distributions.

Identified charged hadron production in collisions at = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

https://doi.org/10.1103/PhysRevC.83.064903

Transverse momentum distributions and yields for , and in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as and scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

Role of AtPol, AtRev1 and AtPol in UV light-induced mutagenesis in Arabidopsis

Nakagawa, Mayu*; Takahashi, Shinya*; Tanaka, Atsushi; Narumi, Issei; Sakamoto, Ayako

Plant Physiology, 155(1), p.414 - 420, 2011/01

https://doi.org/10.1104/pp.110.166082

no abstracts in English

Basic study on activation of antioxidation function in some organs of mice by radon inhalation using new radon exposure device

Nakagawa, Shinya*; Kataoka, Takahiro*; Sakoda, Akihiro*; Ishimori, Yuu; Hanamoto, Katsumi*; Yamaoka, Kiyonori*

Radioisotopes, 57(4), p.241 - 251, 2008/04

https://doi.org/10.3769/radioisotopes.57.241

There are a lot of life style diseases that are related to reactive oxygen species in inductions of the radon therapy, and the further clarification of mechanism is expected. In this study, we investigated the activation of antioxidation function in some organs of mice by radon inhalation using the new radon exposure device. The mice were made to inhale the radon of 400Bq/m or 4000Bq/m with the device. Results show that in brain, lungs, liver and kidney, both the activities of superoxide dismutase and catalase increased, and lipid peroxide levels decreased. This suggests that radon inhalation enhanced the antioxidation function. These findings are important in understanding the mechanism of diseases in which radon therapy is used as treatment, and most of which are called activated oxygen-related diseases.

AtREV3 induces mutations in Arabidopsis

Nakagawa, Mayu; Sakamoto, Ayako; Takahashi, Shinya*; Tanaka, Atsushi; Narumi, Issei

no journal, , 

Plants were exposed to the various DNA-damaging stress in daily life. To survive in such hostile environments, plants developed many mechanisms to avoid or to repair the DNA damage. Yeast and mammals have a mechanism named translesion syntheses (TLS), in which DNA damage is bypassed by specific DNA polymerases. However, TLS generates mutations as a result of incorrect replication (error-prone TLS). We have previously isolated AtREV3, AtREV1 and AtREV7 genes, which are homolog of yeast TLS polymerases. We also showed that disruption of these genes made the plants sensitive to UV-B, -ray and MMC. To determine whether AtREV3 acts in the error-prone TLS, we utilized the beta-glucuronidase (uidA) gene containing single nonsense mutations. Transgenic plants with inactivated uidA were treated with UV-C and reversion events were counted. As a result, mutation frequency was reduced in the rev3 background, indicating that AtREV3 acts in the error-prone TLS in Arabidopsis.

Does Arabidopsis have translesion syntheses ?

Nakagawa, Mayu; Sakamoto, Ayako; Takahashi, Shinya*; Tanaka, Atsushi; Narumi, Issei

no journal, , 

Translesion synthesis and UV-sensitivity in higher plants

Sakamoto, Ayako; Takahashi, Shinya*; Nakagawa, Mayu; Tanaka, Atsushi; Shimizu, Kikuo*; Narumi, Issei

no journal, , 

The harmful effects of UVB in the sunlight are unavoidable problems for higher plants that live on photosynthesis. To keep the genomic information intact, plant cells remove the UV damage formed on the DNA by photoreactivation. Plants also have dark-repair and damage tolerance pathways to prevent growth defect caused by DNA damage. Here we report about and genes, which encode specific polymerases to bypass DNA damage. The - or -disrupted plants were more sensitive to UVB, -ray, and DNA crosslink agents than the wild type, suggesting that these REV proteins are required for plant damage tolerance. Although bacterially expressed AtREV1 protein inserted a dCMP at opposite the AP site, it failed to bypass two major UV damages . This inconsistency makes us propose a novel function of AtREV1 in the UV-tolerance pathway. To evaluate the function of AtREV3 and AtREV1 in bypassing UV-damage, we have detected replication errors that often emerged during damage bypass process. The point-mutated, non-functional genes were introduced into Arabidopsis plants and reversion events (mutations) were detected by blue GUS+ sectors on the somatic tissues. We found that a disruption of or reduced the mutation frequency to 1/4 of the level of the wild type. These results suggest that the AtREV3 and AtREV1 are bypassing the DNA damage in error-prone manner.

Effect of translesion synthesis deficiency on mutation frequency in Arabidopsis

Nakagawa, Mayu; Takahashi, Shinya*; Sakamoto, Ayako; Tanaka, Atsushi; Narumi, Issei

no journal, , 

no abstracts in English