2,203 research outputs found
Heisenberg equation for a nonrelativistic particle on a hypersurface: from the centripetal force to a curvature induced force
In classical mechanics, a nonrelativistic particle constrained on an
curved hypersurface embedded in flat space experiences the centripetal
force only. In quantum mechanics, the situation is totally different for the
presence of the geometric potential. We demonstrate that the motion of the
quantum particle is "driven" by not only the the centripetal force, but also a
curvature induced force proportional to the Laplacian of the mean curvature,
which is fundamental in the interface physics, causing curvature driven
interface evolution.Comment: 4 page
The centripetal force law and the equation of motion for a particle on a curved hypersurface
It is pointed out that the current form of extrinsic equation of motion for a
particle constrained to remain on a hypersurface is in fact a half-finished
version for it is established without regard to the fact that the particle can
never depart from the geodesics on the surface. Once the fact be taken into
consideration, the equation takes that same form as that for centripetal force
law, provided that the symbols are re-interpreted so that the law is applicable
for higher dimensions. The controversial issue of constructing operator forms
of these equations is addressed, and our studies show the quantization of
constrained system based on the extrinsic equation of motion is favorable.Comment: 5 pages, major revisio
Twenty putative palmitoyl-acyl transferase genes with distinct expression patterns in Arabidopsis thaliana
Palmitoylation is a reversible posttranslational addition of palmitate to cysteine residues in proteins through a thioester bond by a family of DHHC (Asp-His-His-Cys) palmitoyltransferases (PATs) involved in cellular signaling, membrane trafficking, and synaptic transmission. There are 20 genes containing DHHC domain predicted to encode putative palmitoyltransferase in Arabidopsis thaliana genome. However, little is known about their characteristics such as genetic relationship and expression profile. Here, we present an overview of the putative PAT genes in A. thaliana focusing on their phylogeny, gene structure and expression profiles in different tissues and under different stresses. Besides conserved DHHC domain, the identity of their cDNA sequences was from 30 to 60%. Temprospatial expression profile of each putative gene of the entire PAT family showed that nineteen of twenty putative PAT members differently expressed in flowers, leaves, stems, roots, seedlings, young and old siliques except At2g40990. Among these nineteen expressed putative PATs, some members expressed at very high levels in certain tissue and some exhibited more even distribution in different tissues. This is the first report on the expression patterns of all these putative PAT genes, which will provide important fundamental data for further identification of their biological functions.Key words: Palmitoylation, palmitoyltransferase, Arabidopsis thaliana, expression pattern
Decreasing erucic acid level by RNAi-mediated silencing of fatty acid elongase 1 (BnFAE1.1) in rapeseeds (Brassica napus L.)
The β-ketoacyl CoA synthase encoded by fatty acid elongase 1 gene (BnFAE1.1) is a rate-limiting enzyme regulating biosynthesis of erucic acid in rapeseeds (Brassica napus). To develop low level of erucic acid in rapeseeds by intron-spliced hairpin RNA, an inverted repeat unit of a partial BnFAE1.1 gene interrupted by a spliceable intron was cloned into pCAMBIA3301, and a seed-specific (Napin) promoter was used to control the transcription of the transgene. Four transgenic plants harboring a single copy of transgene were generated. Expression of endogenous BnFAE1.1 gene in developing T3 seeds was significantly reduced. In mature T3 seeds, erucic acid was decreased by 60.8 to 99.1% compared with wild type seeds, and accounted for 0.36 to 15.56% of total fatty acids. The level of eicosenoic acid was also greatly decreased. Furthermore, it resulted in a significant increase in the level of oleic acid, but total fatty acid content in T3 seeds was the same with that in wild type seeds. In conclusion, the expression of endogenous BnFAE1.1 was efficiently silenced by the designed RNAi silencer, causing a significant down-regulation in the level of erucic acid. Therefore, the RNAi-mediated post-transcriptional silencing of FAE1 gene to reduce oleic acid in rapeseeds was an efficient method to breed some new B. napus lines.Key words: Brassica napus L., fatty acid elongase, intron-spliced hairpin RNA, down-regulation, erucic acid
Forkhead box transcription factor 1: role in the pathogenesis of diabetic cardiomyopathy
published_or_final_versio
Quantum gates implementations in the separated ion-traps by fast laser pulses
An approach is proposed to implement the universal quantum gates between the
ions confined individually in the separated traps. Instead of the typical
adiabatic operations, performed for manipulating the ion-ion coupling, here the
switchable couplings between ions are implemented non-adiabatically by using
the fast laser pulses. Consequently, the desirable quantum gates between the
ions could be implemented by using only a series of laser pulses. The proposal
may be conveniently generalized to the quantum computation with the scalable
ion-traps.Comment: 10 pages, 3figure
Mesenchymal stem cells derived from human induced pluripotent stem cells modulate T-cell phenotypes in allergic rhinitis
published_or_final_versio
Feshbach Projection Operator Partitioning for Quantum Open Systems: Stochastic Approach
Dynamics of a state of interest coupled to a non-Markovian environment is
studied for the first time by concatenating the non-Markovian quantum state
diffusion (QSD) equation and the Feshbach projection operator partitioning
technique. An exact one-dimensional stochastic master equation is derived as a
general tool for controlling an arbitrary component of the system. We show that
the exact one-dimensional stochastic master equation can be efficiently solved
beyond the widely adapted second-order master equations. The generality and
applicability of this hybrid approach is justified and exemplified by several
coherence control problems concerning quantum state protection against leakage
and decoherence.Comment: 5 pages, 3 figure
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