652 research outputs found
(5-Bromo-2-methylphenyl)(4-ethoxyphenyl)methanone
In the title compound, C16H15BrO2, the dihedral angle between the benzene rings is 68.5 (2)°. In the crystal structure, molecules are linked by weak C—H⋯O hydrogen bonds into chains parallel to the b axis
1, 25-Dihydroxyvitamin D3 suppresses cell cycle progression and thus growth of prostate cancer cells by inducing expression of limb bud and heart development (LBH)
Purpose: To investigate the function of limb bud and heart development (LBH) in 1α, 25-dihydroxyvitamin D3 (1,25D)-mediated inhibitory effect on proliferation of prostate cancer cells.Methods: The inhibitory effect of 1,25D on growth and cell cycle progression of lymph node carcinoma of the prostate (LNCaP) cells was determined using cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and flow cytometry, while the expression levels of LBH in response to treatment with 1,25D were determined by quantitative reverse-transcription PCR (qRT-PCR) and western blottingting. The expression levels of LBH in cells were down/up regulated by transfection with siRNA or overexpression plasmids, and then cell growth and cell cycles were measured using the CCK-8 assay, EdU assay, and flow cytometry. Finally, the growth inhibitory effect of 1,25D on LBH knockdown cells were determined using CCK-8 and EdU assays.Results: Treatment with 1,25D arrested LNCaP cells in G0/G1 phase of cell cycle, suppressed the growth of the cells and induced the expression of LBH. Overexpression/knockdown of LBH in LNCaP cells suppressed/promoted cell growth and accumulated/decreased cells in the G0/G1 phase. Moreover, knockdown of LBH reversed the inhibitory effect of 1,25D on cell proliferation of LNCaP cells.Conclusion: Inhibitory effect of 1,25D on cell cycle progression and cell proliferation might be via LBH.Keywords: Cell proliferation, Limb bud and heart development, Prostate cancer, 1α, 25-Dihydroxyvitamin D
Construction of α,α‐disubstituted α‐Amino Acid Derivatives via aza‐Morita‐Baylis‐Hillman Reactions of 2‐Aminoacrylates with Activated Olefins
A useful and convenient strategy for the synthesis of α,α‐disubstituted α‐amino acid (α‐AA) derivatives via aza‐Morita‐Baylis‐Hillman reaction of 2‐aminoacrylates with activated olefins has been developed. A variety of α‐AA derivatives containing an α‐amino tertiary center were synthesized in good to excellent yields. The kinetic profiles and calculated methyl anion affinity (MAA) values were employed to rationalize the reactivities of different Michael acceptors used in the reaction
Tunable Coupling Architectures with Capacitively Connecting Pads for Large-Scale Superconducting Multi-Qubit Processors
We have proposed and experimentally verified a tunable inter-qubit coupling
scheme for large-scale integration of superconducting qubits. The key feature
of the scheme is the insertion of connecting pads between qubit and tunable
coupling element. In such a way, the distance between two qubits can be
increased considerably to a few millimeters, leaving enough space for arranging
control lines, readout resonators and other necessary structures. The increased
inter-qubit distance provides more wiring space for flip-chip process and
reduces crosstalk between qubits and from control lines to qubits. We use the
term Tunable Coupler with Capacitively Connecting Pad (TCCP) to name the
tunable coupling part that consists of a transmon coupler and capacitively
connecting pads. With the different placement of connecting pads, different
TCCP architectures can be realized. We have designed and fabricated a few
multi-qubit devices in which TCCP is used for coupling. The measured results
show that the performance of the qubits coupled by the TCCP, such as and
, was similar to that of the traditional transmon qubits without TCCP.
Meanwhile, our TCCP also exhibited a wide tunable range of the effective
coupling strength and a low residual ZZ interaction between the qubits by
properly tuning the parameters on the design. Finally, we successfully
implemented an adiabatic CZ gate with TCCP. Furthermore, by introducing TCCP,
we also discuss the realization of the flip-chip process and tunable coupling
qubits between different chips.Comment: Main text: 7 pages, 6 figure
Charge-changing cross section measurements of 300 MeV/nucleon Si on carbon and data analysis
Charge-changing cross section () measurements via the
transmission method have made important progress recently aiming to determine
the charge radii of exotic nuclei. In this work, we report a new
measurement of 304(9) MeV/nucleon Si on carbon at
the second Radioactive Ion Beam Line in Lanzhou (RIBLL2) and describe the data
analysis procedure in detail. This procedure is essential to evaluate the
systematic uncertainty in the transmission method. The determined
of 1125(11) mb is found to be consistent with the
existing data at similar energies. The present work will serve as a reference
in the determinations at RIBLL2.Comment: 9 pages, 13 figures, to be published in Chinese Physics
Quantum simulation of topological zero modes on a 41-qubit superconducting processor
Quantum simulation of different exotic topological phases of quantum matter
on a noisy intermediate-scale quantum (NISQ) processor is attracting growing
interest. Here, we develop a one-dimensional 43-qubit superconducting quantum
processor, named as Chuang-tzu, to simulate and characterize emergent
topological states. By engineering diagonal
Aubry-Andr-Harper (AAH) models, we experimentally
demonstrate the Hofstadter butterfly energy spectrum. Using Floquet
engineering, we verify the existence of the topological zero modes in the
commensurate off-diagonal AAH models, which have never been experimentally
realized before. Remarkably, the qubit number over 40 in our quantum processor
is large enough to capture the substantial topological features of a quantum
system from its complex band structure, including Dirac points, the energy
gap's closing, the difference between even and odd number of sites, and the
distinction between edge and bulk states. Our results establish a versatile
hybrid quantum simulation approach to exploring quantum topological systems in
the NISQ era.Comment: Main text: 6 pages, 4 figures; Supplementary: 16 pages, 14 figure
Artificial Intelligence for Science in Quantum, Atomistic, and Continuum Systems
Advances in artificial intelligence (AI) are fueling a new paradigm of
discoveries in natural sciences. Today, AI has started to advance natural
sciences by improving, accelerating, and enabling our understanding of natural
phenomena at a wide range of spatial and temporal scales, giving rise to a new
area of research known as AI for science (AI4Science). Being an emerging
research paradigm, AI4Science is unique in that it is an enormous and highly
interdisciplinary area. Thus, a unified and technical treatment of this field
is needed yet challenging. This work aims to provide a technically thorough
account of a subarea of AI4Science; namely, AI for quantum, atomistic, and
continuum systems. These areas aim at understanding the physical world from the
subatomic (wavefunctions and electron density), atomic (molecules, proteins,
materials, and interactions), to macro (fluids, climate, and subsurface) scales
and form an important subarea of AI4Science. A unique advantage of focusing on
these areas is that they largely share a common set of challenges, thereby
allowing a unified and foundational treatment. A key common challenge is how to
capture physics first principles, especially symmetries, in natural systems by
deep learning methods. We provide an in-depth yet intuitive account of
techniques to achieve equivariance to symmetry transformations. We also discuss
other common technical challenges, including explainability,
out-of-distribution generalization, knowledge transfer with foundation and
large language models, and uncertainty quantification. To facilitate learning
and education, we provide categorized lists of resources that we found to be
useful. We strive to be thorough and unified and hope this initial effort may
trigger more community interests and efforts to further advance AI4Science
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