Coherent oscillations of holes in GaAs0.86P0.14/Al0.7Ga0.3As surface quantum well

We show that in a GaAs_0.86P_0.14/Al_0.7Ga_0.3As near-surface quantum well, there is coherent oscillation of holes observed in time-resolved reflectivity signal when the top barrier of the quantum well is sufficiently thin. The quantum well states interact with the surface states under the influence of the surface electric field. The time period of the observed oscillation is 120±10 fs.     

Ionizing radiation-induced XRCC4 phosphorylation is mediated through ATM in addition to DNA-PK

XRCC4 (X-ray cross-complementation group 4) is a protein associated with DNA ligase IV, which is thought to join two DNA ends at the final step of DNA double-strand break repair through non-homologous end-joining. It has been shown that, in response to irradiation or treatment with DNA damaging agents, XRCC4 undergoes phosphorylation, requiring DNA-PK. Here we explored possible role of ATM, which is structurally related to DNA-PK, in the regulation of XRCC4. The radiosensitizing effects of DNA-PK inhibitor and/or ATM inhibitor were dependent on XRCC4. DNA-PK inhibitor and ATM inhibitor did not affect the ionizing radiation-induced chromatin recruitment of XRCC4. Ionizing radiation-induced phosphorylation of XRCC4 in the chromatin-bound fraction was largely inhibited by DNA-PK inhibitor but further diminished by the combination with ATM inhibitor. The present results indicated that XRCC4 phosphorylation is mediated through ATM as well as DNA-PK, although DNA-PK plays the major role. We would propose a possible model that DNA-PK and ATM acts in parallel upstream of XRCC4, regulating through phosphorylation.     

Brief report: Volume dependence of Grüneisen parameter for solids under extreme compression

The Nie expression is amended in such a way that the expression follows the infinite pressure behaviour, i.e., \(P\to \infty \) or V → 0. A new empirical relationship is developed to predict the values of volume dependence of Grüneisen parameter. NaCl and ε-Fe have been employed to test the suitability of the expression. The results obtained reveal that the relationship is reliable as there is a good agreement between the calculated and the experimental data.     

Measurement of 232Th(n, γ) and 232Th({n}, {2n}) cross-sections at neutron energies of 13.5, 15.5 and 17.28?MeV using neutron activation techniques

The ²³²Th(n, ??) reaction cross-section at average neutron energies of 13.5, 15.5 and 17.28?MeV from the ⁷Li(p, n) reaction has been determined for the first time using activation and off-line ??-ray spectrometric technique. The ²³²Th(n, 2n) cross-section at 17.28?MeV neutron energy has also been determined using the same technique. The experimentally determined ²³²Th(n, ??) and ²³²Th(n, 2n) reaction cross-sections from the present work were compared with the evaluated data of ENDF/BVII and JENDL-4.0 and were found to be in good agreement. The present data, along with literature data in a wide range of neutron energies, were interpreted in terms of competition between ²³²Th(n, ??), (n, f), (n, nf) and (n, xn) reaction channels. The ²³²Th(n, ??) and ²³²Th(n, 2n) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be in good agreement with the experimental data from the present work but were slightly higher than the literature data at lower neutron energies.     

Crystal structure of 4-n-nonyl-4'-cyanobiphenyl

4- n -Nonyl-4-cyanobiphenyl, C22H27N, Mr= 305.45, triclinic, P 1, a=9.765(1)A, b= 11.460(2)A, c=17.860(2)A, alpha=85.460(2), beta=80.870(1), gamma=71.630(1) , V=1871.9(3)A3, Z= 4, Dm=1.079M g -3, Dc= 1.084 M g -3, mu=0.463 mm -1, F (000)=664, lambda (CuK alpha)=1.5418 A, final R and wR 2 are 0.0523 and 0.1559, respectively.     

Numerical and analytical investigations of thermosolutal instability in rotating Rivlin-Ericksen fluid in porous medium with Hall current

Numerical and analytical investigations of the thermosolutal instability in a viscoelastic Rivlin-Ericksen fluid are carried out in the presence of a uniform vertical magnetic field to include the Hall current with a uniform angular velocity in a porous medium. For stationary convection, the stable solute gradient parameter and the rotation have stabilizing effects on the system, whereas the magnetic field and the medium permeability have stabilizing or destabilizing effects on the system under certain conditions. The Hall current in the presence of rotation has stabilizing effects for sufficiently large Taylor numbers, whereas in the absence of rotation, the Hall current always has destabilizing effects. These effects have also been shown graphically. The viscoelastic effects disappear for stationary convection. The stable solute parameter, the rotation, the medium permeability, the magnetic field parameter, the Hall current, and the vis-coelasticity introduce oscillatory modes into the system, which are non-existent in their absence. The sufficient conditions for the non-existence of overstability are also obtained.     

Synchronization of indirectly coupled Lorenz oscillators: An experimental study

The dynamics of indirectly coupled Lorenz circuits is investigated experimentally. The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev. E 81, 046216 (2010) is verified by physical experiments with electronic circuits. Two chaotic systems coupled through a common dynamic environment shows the verity of synchronization behaviours such as anti-phase synchronization, in-phase synchronization, identical synchronization, anti-synchronization, etc.     

Attosecond-correlated dynamics of two electrons in argon

In this work we explored strong field-induced decay of doubly excited transient Coulomb complex Ar ^?? → Ar ²⁺ + 2e. We measured the correlated two-electron emission as a function of carrier envelop phase (CEP) of 6 fs pulses in the non-sequential double ionization (NSDI) of argon. Classical model calculations suggest that the intermediate doubly excited Coulomb complex loses memory of its formation dynamics. We estimated the ionization time difference between the two electrons from NSDI of argon and it is 200 ± 100 as (N Camus et al, Phys. Rev. Lett. 108, 073003 (2012)).