4,873 research outputs found
Recommended from our members
The iFat1 transgene permits conditional endogenous n-3 PUFA enrichment both in vitro and in vivo
Fat-1 transgenic mice, which endogenously convert n-6 PUFA to n-3 PUFA, are a useful tool in health research; however with this model timing of n-3 PUFA enrichment cannot be directly controlled. To add such capability, the novel Cre-recombinase inducible fat-1 (iFat1) transgenic mouse has been developed. The aim of this study was to characterize the utility of the iFat1 transgene as a model of Cre-inducible endogenous n-3 PUFA enrichment. Functionality of the iFat1 transgene was screened both in vitro and in vivo. In the presence of Cre, the iFat1 transgene resulted in a balancing (p < 0.01) of the n-6/n-3 PUFA ratio within phospholipids in the human embryonic kidney 293T cell line. For in vivo analysis, iFat1 transgenic mice were crossed with the R26-Cre-ERT2 (Tam-Cre) mouse line, a tamoxifen inducible Cre-expression model. Tam-Cre/iFat1 double hybrids were transiently treated with tamoxifen at 6â7 weeks, then terminated 3 weeks later. Tamoxifen treated mice had increased (p < 0.05) tissue n-3 PUFA and â„two-fold reduction (p < 0.05) in the n-6/n-3 PUFA ratio of liver, kidney and muscle phospholipids relative to vehicle treated controls. Collectively these findings suggest that the iFat1 transgenic mouse may be a promising tool to help elucidate the temporal effects through which n-3 PUFA impacts health related outcomes
State-Relevant Maxwell's Equation from Kaluza-Klein Theory
We study a five-dimensional perfect fluid coupled with Kaluza-Klein (KK)
gravity. By dimensional reduction, a modified form of Maxwell's equation is
obtained, which is relevant to the equation of state of the source. Since the
relativistic magnetohydrodynamics (MHD) and the 3-dimensional formulation are
widely used to study space matter, we derive the modified Maxwell's equations
and relativistic MHD in 3+1 form. We then take an ideal Fermi gas as an example
to study the modified effect, which can be visible under high density or high
energy condition, while the traditional Maxwell's equation can be regarded as a
result in the low density and low temperature limit. We also indicate the
possibility to test the state-relevant effect of KK theory in a telluric
laboratory.Comment: 11 pages, 3 figures; version published in PR
Selective ethylene trimerization by titanium complexes bearing phenoxy-imine ligands: NMR and EPR Spectroscopic studies of the reaction intermediates
The catalyst systems (FI)TiClâ/MAO (FI = phenoxyimine ligand with an additional arylâOâCHâ donor) display exceptionally high activity in selective ethylene trimerization. By means of NMR and EPR spectroscopy, the nature of the Ti species formed in the catalyst systems (FI)TiClâ/MAO, (FI)TiClâ/MMAO, and (FI)TiClâ/AlRâ/[PhâC]âș[B(CâFâ
)â]â» (R = Me, Et, â±Bu) has been studied. It was shown that outer-sphere ion pairs of the type [(FI)TiIVMeâ]âș[A]â» ([A]â = [MeMAO]â», [MeMMAO]â», [B(CâFâ
)â]â») are formed at the initial stage of the reaction of (FI)TiClâ with MAO, MMAO, and AlMeâ/[PhâC]âș[B(CâFâ
)â]â». These ion pairs further partially convert into TiIII and TiII species. In the systems (FI)TiClâ/MAO and (FI)TiClâ/AlMeâ/[PhâC]âș[B(CâF5)â]â», complexes with the proposed structures (FI)TiIIIMeâ, (FI)TiIICl, and [(FI)TiII(S)]âș[A]â» ([A]â = [MeMAO]â», [B(CâFâ
)4)]â», S = solvent, vacancy) were observed (concentrations of TiIII species was lower than those of the TiII congeners). In contrast, in the system (FI)TiClâ/MMAO, the concentrations of TiIII species (ion pairs of the type [(FI)TiIII(ÎŒ-H)(ÎŒ-Cl)Alâ±Buâ]âș[MeMMAO]â») were higher than those of the TiII counterparts (ion pairs [(FI)TiII(S)]âș[MeMMAO]â»). The system (FI)TiClâ/MMAO displays lower activity and selectivity in 1-hexene formation, in comparison to (FI)TiClâ/MAO, due to undesirable PE generation. Probably, TiII and TiIV ion pairs are those participating in ethylene trimerization
The Large Scale Bias of Dark Matter Halos: Numerical Calibration and Model Tests
We measure the clustering of dark matter halos in a large set of
collisionless cosmological simulations of the flat LCDM cosmology. Halos are
identified using the spherical overdensity algorithm, which finds the mass
around isolated peaks in the density field such that the mean density is Delta
times the background. We calibrate fitting functions for the large scale bias
that are adaptable to any value of Delta we examine. We find a ~6% scatter
about our best fit bias relation. Our fitting functions couple to the halo mass
functions of Tinker et. al. (2008) such that bias of all dark matter is
normalized to unity. We demonstrate that the bias of massive, rare halos is
higher than that predicted in the modified ellipsoidal collapse model of Sheth,
Mo, & Tormen (2001), and approaches the predictions of the spherical collapse
model for the rarest halos. Halo bias results based on friends-of-friends halos
identified with linking length 0.2 are systematically lower than for halos with
the canonical Delta=200 overdensity by ~10%. In contrast to our previous
results on the mass function, we find that the universal bias function evolves
very weakly with redshift, if at all. We use our numerical results, both for
the mass function and the bias relation, to test the peak-background split
model for halo bias. We find that the peak-background split achieves a
reasonable agreement with the numerical results, but ~20% residuals remain,
both at high and low masses.Comment: 11 pages, submitted to ApJ, revised to include referee's coment
Suppression of decoherence by bath ordering
The dynamics of two coupled spins-1/2 coupled to a spin-bath is studied as an
extended model of the Tessieri-Wilkie Hamiltonian \cite{TWmodel}. The pair of
spins served as an open subsystem were prepared in one of the Bell states and
the bath consisted of some spins-1/2 is in a thermal equilibrium state from the
very beginning. It is found that with the increasing the coupling strength of
the bath spins, the bath forms a resonant antiferromagnetic order. The
polarization correlation between the two spins of the subsystem and the
concurrence are recovered in some extent to the isolated subsystem. This
suppression of the subsystem decoherence may be used to control the quantum
devices in practical applications.Comment: 32 pages, Chinese Physics (accepted
Close Encounters of Tight Binary Stars with Stellar-mass Black Holes
Strong dynamical interactions among stars and compact objects are expected in
a variety of astrophysical settings, such as star clusters and the disks of
active galactic nuclei. Here, via a suite of 3D hydrodynamics simulations using
the moving-mesh code {\small AREPO}, we investigate the effect of close
encounters between an equal-mass circular binary star with mass of
or and single black hole (BH), focusing on the
formation of transient phenomena and their properties. Stars can be disrupted
by the BH during three-body dynamical interactions, naturally producing
electromagnetic transient phenomena. Encounters with impact parameters smaller
than the semimajor axis of the initial binary frequently lead to a variety of
transients whose electromagnetic signatures are qualitatively different from
those of ordinary tidal disruption events involving just two bodies. These
include the simultaneous or successive full disruptions of both stars and one
full disruption of one star accompanied by successive partial disruptions of
the other star. On the other hand, when the impact parameter is larger than the
semimajor axis of the initial binary, the binary is either simply tidally
perturbed or dissociated into bound and unbound single stars (``micro-Hills''
mechanism). We found that the dissociation of binaries consisting of
stars can produce the formation of a runaway star and an active
isolated BH moving away from one another. Also, one of the unbound stars
produced in the binary dissociation can either form an interacting binary with
the BH, or a non-interacting, hard binary (which may later shrink via weak
encounters); both of these could be candidates of BH high- and low-mass X-ray
binaries with periodic luminosity modulation.Comment: 13 pages, 8 figures, 2 tables. submitted to MNRAS. Comments welcome
Dear Reader
<p>Cell scratch test and Transwell were used to measure the migration abilities of HSVSMCs. NC = Negative control group, only control siRNA transfected; GAS5(-) = lncRNA-GAS5 knockdown group transfected with silence siRNA. <b>A:</b>Cell scratch test was used to measure the migration abilities of HSVSMCs. The results showed that the HSVSMCs have the best migration abilities in the first 24 hours. Values are mean±SE, N = 4. <b>B:</b> The migration abilities of HSVSMCs measured by Transwell. After transfected by lncRNA-GAS5 siRNA for 48 hours, the HSVSMCs were passage into the Transwell Inserts. Then 4 hours, 7 hours, 10 hours later, the migration HSVSMCs were photographed and counted, respectively. Knockdown of lncRNA-GAS5 expression promotes migration of HSVSMCs. Optical microscope images under 200x magnification. <b>C:</b> The migration abilities of HSVSMCs were reflected indirectly by the new migration cells counting with Transwell. Silencing of lncRNA-GAS5 expression increses migration ability of HSVSMCs. Values are mean±SE, N = 10; *, P<0.05.</p
Redshift Evolution of the Nonlinear Two-Point Correlation Function
This paper presents a detailed theoretical study of the two-point correlation
function for both dark matter halos and the matter density field in five
cosmological models with varying matter density and neutrino
fraction . The objectives of this systematic study are to evaluate
the nonlinear gravitational effects on , to contrast the behavior of
for halos vs. matter, and to quantify the redshift evolution of and its
dependence on cosmological parameters. Overall, for halos exhibits
markedly slower evolution than for matter, and its redshift dependence is
much more intricate than the single power-law parameterization used in the
literature. Of particular interest is that the redshift evolution of the
halo-halo correlation length depends strongly on and
, being slower in models with lower or higher
. Measurements of to higher redshifts can therefore be a
potential discriminator of cosmological parameters. The evolution rate of
for halos within a given model increases with time, passing the phase of fixed
comoving clustering at to 3 toward the regime of stable clustering at
. The shape of the halo-halo , on the other hand, is well
approximated by a power law with slope -1.8 in all models and is not a
sensitive model discriminator.Comment: 22 pages, 8 postscript figures, AAS LaTeX v4.0. Accepted for
publication in The Astrophysical Journal, Vol. 510 (January 1 1999
- âŠ