720 research outputs found
The prenylated rab GTPase receptor PRA1.F4 contributes to protein exit from the golgi apparatus
Prenylated Rab acceptor1 (PRA1) functions in the recruitment of prenylated Rab proteins to their cognate organelles. Arabidopsis (Arabidopsis thaliana) contains a large number of proteins belonging to the AtPRA1 family. However, their physiological roles remain largely unknown. Here, we investigated the physiological role of AtPRA1.F4, a member of the AtPRA1 family. A T-DNA insertion knockdown mutant of AtPRA1.F4, atpra1.f4, was smaller in stature than parent plants and possessed shorter roots, whereas transgenic plants overexpressing HA:AtPRA1.F4 showed enhanced development of secondary roots and root hairs. However, both overexpression and knockdown plants exhibited increased sensitivity to high-salt stress, lower vacuolar Na+/K+-ATPase and plasma membrane ATPase activities, lower and higher pH in the vacuole and apoplast, respectively, and highly vesiculated Golgi apparatus. HA:AtPRA1.F4 localized to the Golgi apparatus and assembled into high-molecular-weight complexes. atpra1.f4 plants displayed a defect in vacuolar trafficking, which was complemented by low but not high levels of HA:AtPRA1.F4. Overexpression of HA:AtPRA1.F4 also inhibited protein trafficking at the Golgi apparatus, albeit differentially depending on the final destination or type of protein: trafficking of vacuolar proteins, plasma membrane proteins, and trans-Golgi network (TGN)-localized SYP61 was strongly inhibited; trafficking of TGN-localized SYP51 was slightly inhibited; and trafficking of secretory proteins and TGN-localized SYP41 was negligibly or not significantly inhibited. Based on these results, we propose that Golgi-localized AtPRA1.F4 is involved in the exit of many but not all types of post-Golgi proteins from the Golgi apparatus. Additionally, an appropriate level of AtPRA1.F4 is crucial for its function at the Golgi apparatus. ? 2017 American Society of Plant Biologists. All rights reserved.111Ysciescopu
Temperature and Frequency Dependence of Complex Conductance of Ultrathin YBa2Cu3O7-x Films: A Study of Vortex-Antivortex Pair Unbinding
We have studied the temperature dependencies of the complex sheet conductance
of 1-3 unit cell (UC) thick YBa2Cu3O7-x films sandwiched between semiconducting
Pr0.6Y0.4Ba2Cu3O7-x layers at high frequencies. Experiments have been carried
out in a frequency range between: 2 - 30 MHz with one-spiral coil technique,
100 MHz - 1 GHz frequency range with a new technique using the spiral coil
cavity and at 30 GHz by aid of a resonant cavity technique. The real and
imaginary parts of the mutual-inductance between a coil and a film were
measured and converted to complex conductivity by aid of the inversion
procedure. We have found a quadratic temperature dependence of the kinetic
inductance, L_k^-1(T), at low temperatures independent of frequency, with a
break in slope at T^dc_BKT, the maximum of real part of conductance and a large
shift of the break temperature and the maximum position to higher temperatures
with increasing frequency. We obtain from these data the universal ratio
T^dc_BKT/L_k^-1(T^dc_BKT) = 25, 25, and 17 nHK for 1-, 2- and 3UC films,
respectively in close agreement with theoretical prediction of 12 nHK for
vortex-antivortex unbinding transition. The activated temperature dependence of
the vortex diffusion constant was observed and discussed in the framework of
vortex-antivortex pair pinning.
PACS numbers: 74.80.Dm, 74.25.Nf, 74.72.Bk, 74.76.BzComment: PDF file, 10 pages, 6 figures, to be published in J. Low Temp. Phys.;
Proc. of NATO ARW: VORTEX 200
Neutron beam test of CsI crystal for dark matter search
We have studied the response of Tl-doped and Na-doped CsI crystals to nuclear
recoils and 's below 10 keV. The response of CsI crystals to nuclear
recoil was studied with mono-energetic neutrons produced by the
H(p,n)He reaction. This was compared to the response to Compton
electrons scattered by 662 keV -ray. Pulse shape discrimination between
the response to these 's and nuclear recoils was studied, and quality
factors were estimated. The quenching factors for nuclear recoils were derived
for both CsI(Na) and CsI(Tl) crystals.Comment: 21pages, 14figures, submitted to NIM
Hamiltonian theory of gaps, masses and polarization in quantum Hall states: full disclosure
I furnish details of the hamiltonian theory of the FQHE developed with Murthy
for the infrared, which I subsequently extended to all distances and apply it
to Jain fractions \nu = p/(2ps + 1). The explicit operator description in terms
of the CF allows one to answer quantitative and qualitative issues, some of
which cannot even be posed otherwise. I compute activation gaps for several
potentials, exhibit their particle hole symmetry, the profiles of charge
density in states with a quasiparticles or hole, (all in closed form) and
compare to results from trial wavefunctions and exact diagonalization. The
Hartree-Fock approximation is used since much of the nonperturbative physics is
built in at tree level. I compare the gaps to experiment and comment on the
rough equality of normalized masses near half and quarter filling. I compute
the critical fields at which the Hall system will jump from one quantized value
of polarization to another, and the polarization and relaxation rates for half
filling as a function of temperature and propose a Korringa like law. After
providing some plausibility arguments, I explore the possibility of describing
several magnetic phenomena in dirty systems with an effective potential, by
extracting a free parameter describing the potential from one data point and
then using it to predict all the others from that sample. This works to the
accuracy typical of this theory (10 -20 percent). I explain why the CF behaves
like free particle in some magnetic experiments when it is not, what exactly
the CF is made of, what one means by its dipole moment, and how the comparison
of theory to experiment must be modified to fit the peculiarities of the
quantized Hall problem
Hot Spots and Transition from d-Wave to Another Pairing Symmetry in the Electron-Doped Cuprate Superconductors
We present a simple theoretical explanation for a transition from d-wave to
another superconducting pairing observed in the electron-doped cuprates. The
d_{x^2-y^2} pairing potential Delta, which has the maximal magnitude and
opposite signs at the hot spots on the Fermi surface, becomes suppressed with
the increase of electron doping, because the hot spots approach the Brillouin
zone diagonals, where Delta vanishes. Then, the d_{x^2-y^2} pairing is replaced
by either singlet s-wave or triplet p-wave pairing. We argue in favor of the
latter and discuss experiments to uncover it.Comment: 6 pages, 4 figures, RevTeX 4. V.2: Extra figure and many references
added. V.3: Minor update of references for the proof
Precise measurement of hadronic tau-decays with an eta meson
We have studied hadronic tau decay modes involving an eta meson using 490
fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy
e+e- collider. The following branching fractions have been measured: B(tau- ->
K- eta nu)=(1.58 +- 0.05 +- 0.09)x 10^{-4}, B(tau- -> K- pi0 eta nu)=(4.6 +-
1.1 +- 0.4)x 10^{-5}, B(tau- -> pi- pi0 eta nu)=(1.35 +- 0.03 +- 0.07)x
10^{-3}, B(tau- -> pi- KS eta nu)=(4.4 +- 0.7 +- 0.2)x 10^{-5}, and B(tau- ->
K^{*-} eta nu)=(1.34 +- 0.12 +- 0.09)x 10^{-4}. These results are substantially
more precise than previous measurements. The new measurements are compared with
theoretical calculations based on the CVC hypothesis or the chiral perturbation
theory. We also set upper limits on branching fractions for tau decays into K-
KS eta nu, pi- KS pi0 eta nu, K- eta eta nu, pi- eta eta nu and non-resonant K-
pi^0 eta nu final states.Comment: 24 pages, 7 figure
Measurement of the near-threshold cross section using initial-state radiation
We report measurements of the exclusive cross section for , where or , in the center-of-mass energy range from the threshold to with initial-state radiation. The
analysis is based on a data sample collected with the Belle detector with an
integrated luminosity of 673 .Comment: Presented at EPS07 and LP07 conferences, published in PRD(RC
Search for Resonant Decays at Belle
We report measurements and searches for resonant decays where is a
meson or
the X(3872) particle.Comment: accepted by Physics Letters
Study of charmonia in four-meson final states produced in two-photon collisions
We report measurements of charmonia produced in two-photon collisions and
decaying to four-meson final states, where the meson is either a charged pion
or a charged kaon. The analysis is based on a 395fb^{-1} data sample
accumulated with the Belle detector at the KEKB electron-positron collider. We
observe signals for the three C-even charmonia eta_c(1S), chi_{c0}(1P) and
chi_{c2}(1P) in the pi^+pi^-pi^+pi^-, K^+K^-pi^+pi^- and K^+K^-K^+K^- decay
modes. No clear signals for eta_c(2S) production are found in these decay
modes. We have also studied resonant structures in charmonium decays to
two-body intermediate meson resonances. We report the products of the
two-photon decay width and the branching fractions, Gamma_{gamma gamma}B, for
each of the charmonium decay modes.Comment: 22 pages, 12 figure
Search for B+ -> D*+ pi0 decay
We report on a search for the doubly Cabibbo suppressed decay B+ -> D*+ pi0,
based on a data sample of 657 million BBbar pairs collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider.
We find no significant signal and set an upper limit of Br(B+ -> D*+ pi0) < 3.6
x 10^-6 at the 90% confidence level. This limit can be used to constrain the
ratio between suppressed and favored B -> D* pi decay amplitudes, r < 0.051, at
the 90% confidence level.Comment: 5pages, 2figures, submitted to PRL (v1); PRL published version (v2:
minor corrections in the text
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