2,602 research outputs found
8-Hydroxyquinoline benzoates as highly sensitive fluorescent chemosensors for transition metal ions
8-Hydroxyquinoline benzoates were developed as a new set of 8-HQ derivatives for highly sensitive fluorescent chemosensors for transition metal ions. A prominent fluorescence enhancement was found in the presence of transition metal ions such as Hg2+ and Cu2+, and this was suggested to result from the suppression of radiationless transitions from the n pi* state in the chemosensors
A signal cascade originated from epidermis defines apical-basal patterning of Arabidopsis shoot apical meristems
In multicellular organisms, a long-standing question is how spatial patterns of distinct cell types are initiated and maintained during continuous cell division and proliferation. Along the vertical axis of plant shoot apical meristems (SAMs), stem cells are located at the top while cells specifying the stem cells are located more basally, forming a robust apical-basal pattern. We previously found that in Arabidopsis SAMs, the HAIRY MERISTEM (HAM) family transcription factors form a concentration gradient from the epidermis to the interior cell layers, and this gradient is essential for the stem cell specification and the apical-basal patterning of the SAMs. Here, we uncover that epidermis specific transcription factors, ARABIDOPSIS THALIANA MERISTEM LAYER 1 (ATML1) and its close homolog, define the concentration gradient of HAM in the SAM through activating a group of microRNAs. This study provides a molecular framework linking the epidermis-derived signal to the stem cell homeostasis in plants
A transcriptional factor B paralog functions as an activator to DNA damage-responsive expression in archaea
Identifying the Riemann zeros by periodically driving a single qubit
The Riemann hypothesis, one of the most important open problems in pure
mathematics, implies the most profound secret of prime numbers. One of the most
interesting approaches to solve this hypothesis is to connect the problem with
the spectrum of the physical Hamiltonian of a quantum system. However, none of
the proposed quantum Hamiltonians have been experimentally feasible.Here, we
report the first experiment to identify the first non-trivial zeros of the
Riemann zeta function and the first two zeros of P\'olya's fake zeta function,
using a novel Floquet method, through properly designed periodically driving
functions. According to this method, the zeros of these functions are
characterized by the occurrence of crossings of quasi-energies when the
dynamics of the system are frozen. The experimentally obtained zeros are in
excellent agreement with their exact values. Our study provides the first
experimental realization of the Riemann zeros, which may provide new insights
into this fundamental mathematical problem.Comment: 5 pages, 7 figure
High-Q exterior whispering gallery modes in a metal-coated microresonator
We propose a kind of plasmonic whispering gallery modes highly localized on
the exterior surface of a metal-coated microresonator. This exterior (EX)
surface mode possesses high quality factors at room temperature, and can be
efficiently excited by a tapered fiber. The EX mode can couple to an interior
(IN) mode and this coupling produces a strong anti-crossing behavior, which not
only allows conversion of IN to EX modes, but also forms a long-lived
anti-symmetric mode. As a potential application, the EX mode could be used for
a biosensor with a sensitivity high up to 500 nm per refraction index unit, a
large figure of merit, and a wide detection range
catena-Poly[[{2-[(2-hydroxyethyl)iminomethyl]-6-methoxyphenolato}copper(II)]-μ-thiocyanato]
In the title thiocyanate-bridged polynuclear copper(II) complex, [Cu(C10H12NO3)(NCS)]n, the Cu atom is five-coordinated in a square-pyramidal geometry, with one phenolato O, one imino N and one hydroxy O atom of a Schiff base ligand and one thiocyanato N atom defining the basal plane, and with one thiocyanato S atom occupying the apical position. In the crystal structure, pairs of adjacent complex molecules are linked through intermolecular O—H⋯O hydrogen bonds into dimers. The dimers are further linked via Cu⋯S interactions, forming two-dimensional layers parallel to the bc plane
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