5,282 research outputs found
Non-perturbative Dynamical Decoupling Control: A Spin Chain Model
This paper considers a spin chain model by numerically solving the exact
model to explore the non-perturbative dynamical decoupling regime, where an
important issue arises recently (J. Jing, L.-A. Wu, J. Q. You and T. Yu,
arXiv:1202.5056.). Our study has revealed a few universal features of
non-perturbative dynamical control irrespective of the types of environments
and system-environment couplings. We have shown that, for the spin chain model,
there is a threshold and a large pulse parameter region where the effective
dynamical control can be implemented, in contrast to the perturbative
decoupling schemes where the permissible parameters are represented by a point
or converge to a very small subset in the large parameter region admitted by
our non-perturbative approach. An important implication of the non-perturbative
approach is its flexibility in implementing the dynamical control scheme in a
experimental setup. Our findings have exhibited several interesting features of
the non-perturbative regimes such as the chain-size independence, pulse
strength upper-bound, noncontinuous valid parameter regions, etc. Furthermore,
we find that our non-perturbative scheme is robust against randomness in model
fabrication and time-dependent random noise
Genetically engineered pre-microRNA-34a prodrug suppresses orthotopic osteosarcoma xenograft tumor growth via the induction of apoptosis and cell cycle arrest.
Osteosarcoma (OS) is the most common primary malignant bone tumor in children, and microRNA-34a (miR-34a) replacement therapy represents a new treatment strategy. This study was to define the effectiveness and safety profiles of a novel bioengineered miR-34a prodrug in orthotopic OS xenograft tumor mouse model. Highly purified pre-miR-34a prodrug significantly inhibited the proliferation of human 143B and MG-63 cells in a dose dependent manner and to much greater degrees than controls, which was attributed to induction of apoptosis and G2 cell cycle arrest. Inhibition of OS cell growth and invasion were associated with release of high levels of mature miR-34a from pre-miR-34a prodrug and consequently reduction of protein levels of many miR-34a target genes including SIRT1, BCL2, c-MET, and CDK6. Furthermore, intravenous administration of in vivo-jetPEI formulated miR-34a prodrug significantly reduced OS tumor growth in orthotopic xenograft mouse models. In addition, mouse blood chemistry profiles indicated that therapeutic doses of bioengineered miR-34a prodrug were well tolerated in these animals. The results demonstrated that bioengineered miR-34a prodrug was effective to control OS tumor growth which involved the induction of apoptosis and cell cycle arrest, supporting the development of bioengineered RNAs as a novel class of large molecule therapeutic agents
Quantum speed limit for complex dynamics
Quantum speed limit focuses on the minimum time scale for a fixed mission and
hence is important in quantum information where fast dynamics is usually
beneficial. Recently an operational definition of quantum speed limit (OQSL)
was proposed, which reveals the intrinsic minimum time for time-independent
Hamiltonians. However, a general method to evaluate the OQSL for time-dependent
Hamiltonians, especially when noises are involved, is still in lack. Hereby we
provide the expression of OQSL for a certain type of time-dependent
Hamiltonians and propose a three-step (classification-regression-calibration)
methodology based on machine learning for the evaluation of OQSL in complex
dynamics.Comment: 24 pages, 14 figures, 1 tabl
Design of super-efficient mixer based on induced charge electroosmotic
The super-efficient sample mixing induced by the induced-charge electrokinetic flow around conducting/Janus cylinder was numerically studied in a confined |U-shaped microchannel with suddenly applied DC weak electric filed. It’s found that there are four large circulations around the conducting cylinder and two smaller circulations around the Janus cylinder. The results show that samples can still be well mixed with high flux due to the induced electroosmosis. It is demonstrated that the local flow circulations provide effective means to enhance the flow mixing between different solutions. The dependence of the degree of mixing enhancement on the electric field is also predicted
Note On Certain Inequalities for Neuman Means
In this paper, we give the explicit formulas for the Neuman means ,
, and , and present the best possible upper and lower
bounds for theses means in terms of the combinations of harmonic mean ,
arithmetic mean and contraharmonic mean .Comment: 9 page
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