27,499 research outputs found
Requirement of the FATC domain of protein kinase Tel1 for localization to DNA ends and target protein recognition
Two large phosphatidylinositol 3-kinase-related protein kinases (PIKKs), ATM and ATR, play a central role in the DNA damage response pathway. PIKKs contain a highly conserved extreme C-terminus called the FRAP-ATM-TRRAP-C-terminal (FATC) domain. In budding yeast, ATM and ATR correspond to Tel1 and Mec1, respectively. In this study, we characterized functions of the FATC domain of Tel1 by introducing substitution or truncation mutations. One substitution mutation, termed tel1-21, and a truncation mutation, called tel1- Î"C, did not significantly affect the expression level. The tel1-21 mutation impaired the cellular response to DNA damage and conferred moderate telomere maintenance defect. In contrast, the tel1-Î"C mutation behaved like a null mutation, conferring defects in both DNA damage response and telomere maintenance. Tel1-21 protein localized to DNA ends as effectively as wild-type Tel1 protein, whereas Tel1-Î"C protein failed. Introduction of a hyperactive TEL1-hy mutation suppressed the tel1-21 mutation but not the tel1-Î"C mutation. In vitro analyses revealed that both Tel1-21 and Tel1-Î"C proteins undergo efficient autophosphorylation but exhibit decreased kinase activities toward the exogenous substrate protein, Rad53. Our results show that the FATC domain of Tel1 mediates localization to DNA ends and contributes to phosphorylation of target proteins. © 2015 Ogi, Goto, Ghosh, et al
Lost equivalence of nonlinear sigma and models on noncommutative space
We show that the equivalence of nonlinear sigma and models which is
valid on the commutative space is broken on the noncommutative space. This
conclusion is arrived at through investigation of new BPS solitons that do not
exist in the commutative limit.Comment: 17 pages, LaTeX2
Critical properties of the double exchange ferromagnet Nd0.4Pb0.4MnO3
Results of a study of dc-magnetization M(T, H), performed on a Nd0.6Pb0.4MnO3
single crystal in the temperature range around T_C (Curie temperature) which
embraces the critical region | epsilon | = |T -T_C |/T_C <= 0.05 are reported.
The magnetic data analyzed in the critical region using the Kouvel-Fisher
method give the values for the T_C =156.47 +/- 0.06 K and the critical
exponents, beta = 0.374 +/- 0.006 (from the temperature dependence of
magnetization), and gamma = 1.329 +/- 0.003 (from the temperature dependence of
initial susceptibility). The critical isotherm M(T_C, H) gives delta = 4.547
+/- 0.1. Thus the scaling law gamma+beta=delta beta is fulfilled. The critical
exponents obey the single scaling-equation of state M(H, epsilon) = epsilon^b
f_+/- (H/epsilon^(beta + gamma)) where, f_+ for T > T_C and f_- for T< T_C. The
exponent values are very close to those expected for the universality class of
3D Heisenberg ferromagnets with short-range interactions.Comment: 19 pages, including 6 figure
Growth and physical property study of single nanowire (diameter ~ 45nm) of half doped Manganite
We report here the growth and characterization of functional oxide nanowire
of hole doped manganite of La0.5Sr0.5MnO3 (LSMO). We also report four probe
electrical resistance measurement of single nanowire of LSMO (diameter ~ 45nm)
using FIB fabricated electrodes. The wires were fabricated by hydrothermal
method using autoclave at a temperature of 270 oC. The elemental analysis and
physical property like electrical resistivity were studied at individual
nanowire level. The quantitative determination of Mn valency and elemental
mapping of constituent elements was done by using Electron Energy Loss
Spectroscopy (EELS) in the Scanning Transmission Electron Microscopy (STEM)
mode. We addressed the important issue of whether as a result of size reduction
the nanowires can retain the desired composition, structure and physical
properties. The nanowires used were found to have a ferromagnetic transition
(TC) at around 325 K which is very close to the bulk value of around 330 K
found in single crystal of the same composition confirming that the functional
behavior is likely to be retained even after size reduction of the nanowires to
a diameter of 45 nm. The electrical resistivity shows insulating behavior
within the temperature range measured, which is very much similar to the bulk
system.Comment: 11 pages, 7 figures, accepted in Journal of Nanomaterial
Three flavour Quark matter in chiral colour dielectric model
We investigate the properties of quark matter at finite density and
temperature using the nonlinear chiral extension of Colour Dielectric Model
(CCM). Assuming that the square of the meson fields devlop non- zero vacuum
expectation value, the thermodynamic potential for interacting three flavour
matter has been calculated. It is found that remain zero
in the medium whereas changes in the medium. As a result, and
quark masses decrease monotonically as the temperature and density of the quark
matter is increased.In the present model, the deconfinement density and
temperature is found to be lower compared to lattice results. We also study the
behaviour of pressure and energy density above critical temperature.Comment: Latex file. 5 figures available on request. To appear in Phys. Rev.
Mapping of Large Scale 158 micron [CII] Line Emission: Orion A
We present the first results of an observational programme undertaken to map
the fine structure line emission of singly ionized carbon ([CII] 157.7409
micron) over extended regions using a Fabry Perot spectrometer newly installed
at the focal plane of a 100cm balloon-borne far-infrared telescope. This new
combination of instruments has a velocity resolution of ~200 km/s and an
angular resolution of 1.5'. During the first flight, an area of 30'x15' in
Orion A was mapped. The observed [CII] intensity distribution has been compared
with the velocity-integrated intensity distributions of 13CO(1-0), CI(1-0) and
CO(3-2) from the literature. The observed line intensities and ratios have been
analyzed using the PDR models by Kaufman et al. 1999 to derive the incident UV
flux and volume density at a few selected positions.Comment: To appear in Astronomy & Astrophysic
Realization of Optimal Disentanglement by Teleportation via Separable Channel
We discuss here the best disentanglement processes of states of two two-level
systems which belong to (i) the universal set, (ii) the set in which the states
of one party lie on a single great circle of the Bloch sphere, and (iii) the
set in which the states of one party commute with each other, by teleporting
the states of one party (on which the disentangling machine is acting) through
three particular type of separable channels, each of which is a mixture of Bell
states. In the general scenario, by teleporting one party's state of an
arbitrary entangled state of two two-level parties through some mixture of Bell
states, we have shown that this entangled state can be made separable by using
a physically realizable map , acting on one party's states, if
, where
(for ), and .Comment: 20 pages Late
- …