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81.
C. Chagalj T. C. P. DePaoli A. A. Hager L. A. Palaoro E. Rubin de Celis H. A. Farach C. P. Poole Jr. 《Il Nuovo Cimento D》1984,4(3):245-254
Summary Human erythrocytes were labelled with nitroxide, the spin label SYNVAR 101, under various experimental conditions. A study
was made of the influence of antireductants on the labelling efficiency and the kinetics of the radical decay during the labelling
process. The antireductant hydrogen peroxide was effective in suppressing the decay, whereas ferricyanide was not very effective
in this role. The nitroxide radical concentration in a nondialyzed plasma suspension of spin-labelled erythrocytes continuously
decayed exponentially with a time constant of 35 min. Nitroxide radicals in nondialyzed plasma exhibited a similar decay to
a final residual value which was small relative to the initial concentration. Dialyzing the plasma raised the residual concentration
to three quarters of the initial value without changing the decay time.
Riassunto Eritrociti umani sono marcati con ossido di azoto, il marchio di spin SYNVAR 101, in varie condizioni sperimentali. Si è fatto uno studio dell’influenza degli agenti antiriducenti sulla capacità di marcare e sulla cinetica del decadimento dei radicali durante il processo di marcatura. Il perossido d’idrogeno antiriducente era efficacie nel sopprimere il decadimento, mentre il ferrocianuro non era molto efficacie in questo roulo. La concentrazione dei radicali dell’ossido di azoto in una sospensione di plasma non dializzato degli eritrociti marcati secondo lo spin decade continuamente in maniera esponenziale con una costante di tempo di 35 min. I radicali dell’ossido di azoto nel plasma non dializzato esibiscono un decadimento simile al valore residuo finale che era piccolo in relazione alla concentrazione iniziale. Dializzare il plasma aumenta la concentrazione residua a tre quarti del valore iniziale senza cambiare il tempo di decadimento.
Резюме В различных эксрериментальных условиях метятся человеческие эритроциты с окисью азота. Исследуются влияния антивосстановителя на эффективность нанесения метки и кинетику распада радикалов в процессе нанесения метки, Перекись водорода, как антивосстановитель, является эффективной для подавления распада, тогда как феррицианид не очень эффективен в этой. Концетрация радикалов окиси азота в суспензии недиализированной плазмы эритроцитов со спиновой меткой уменьшается эксоненциально с временной постоянной, равной 35 мин. Радикалы окиси азота в недиализированной плазме обнаруживают аналогичный распад, причем конечная остаточная величина концентрации оказывается малой по сравнений с начальной концентрацией. Диализация рлазмы увеличивает остаточную концентрацию до трех четвертых начальной без изменения времени распада.相似文献
82.
The convergence properties of an iterative solution technique for the Reduced Navier–Stokes equations are examined for two-dimensional steady subsonic flow over bump and trough geometries. Techniques for decreasing the sensitivity to the initial pressure approximation, for fine meshes in particular, are investigated. They are shown to improve the robustness of the relaxation process and to decrease the computational work required to obtain a converged solution. A semi-coarsening multigrid technique that has previously been found to be particularly advantageous for high-Reynolds-number (Re) flows with flow separation and with highly stretched surface-normal grids is applied herein to further accelerate convergence. Solutions are obtained for the laminar flow over a trough that is more severe than has been considered to date. Sufficient axial grid refinement in this case leads to a shock-like reattachment and, for sufficiently large Re, to a local ‘divergence’ of the numerical computations. This ‘laminar flow breakdown’ appears to be related to an instability associated with high-frequency fine-grid modes that are not resolvable with the present modelling. This behaviour may be indicative of dynamic stall or of incipient transition. The breakdown or instability is shown to be controllable by suitable introduction of transition turbulence models or by laminar flow control, i.e. small amounts of wall suction. This lends further support to the hypothesis that the instability is of a physical rather than numerical character and suggests that full three-dimensional analysis is required to properly capture the flow behaviour. Another inference drawn from this investigation is that there is a need for careful grid refinement studies in high-Re flow computations, since coarser grids may yield oscillation-free solutions that cannot be obtained on finer grids. 相似文献
83.
84.
85.
86.
Karl Rubin 《Inventiones Mathematicae》1988,93(3):701-713
Partially supported by NSF grant DMS-8501937 and by a Sloan fellowship 相似文献
87.
88.
G. Y. Fraikin Marina G. Strakhovskaya Leonid B. Rubin 《Photochemistry and photobiology》1981,33(6):839-843
Abstract— This paper considers mechanisms of near-UV (334nm) induced photoprotection as well as potentiation of far-UV (254 nm) lethality in Candida guilliermondii. Using exogenous precursors of serotonin, it appears that the above two mechanisms involve photoactivated synthesis of serotonin. It has been postulated that the serotonin effect could take place by binding to DNA. 相似文献
89.
Ephraim L. Rubin Prem K. Khosla 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1970,21(6):962-977
Zusammenfassung In dieser Arbeit lösen wir die eindimensionale Gasströmungsgleichung einschliesslich des Effektes der Strahlungsübergänge für zähe und für reibungsfreie Fälle. Der Charakter der Hauptgleichung wird bestimmt und man findet, dass in Gegenwart von Strahlungsprozessen der zähe Fall zu parabolischen Charakteristiken führt. Die Stabilität des numerischen Schemas wird untersucht und ein Grenzkriterium für den Fall starker Strahlung wird bestimmt. Im Einklang mit diesem Kriterium wird gefunden, dass im Falle starker Stösse und starker Strahlung die Rechnungen sehr langwierig werden.
This research was conducted under the soponsorship of the Office of Naval Research, under Contract No. Nonr 839(34), Project No. NR 061-135. 相似文献
This research was conducted under the soponsorship of the Office of Naval Research, under Contract No. Nonr 839(34), Project No. NR 061-135. 相似文献
90.