3,815 research outputs found
Phase transitions and spin excitations of spin-1 bosons in optical lattice
We investigate ground state properties of spin-1 bosonic system trapped in
optical lattice with extended standard basis operator (SBO) method. For both
ferromagnetic () systems, we
analytically figure out the symmetry properties in Mott-insulator and
superfluid phases, which would provide a deeper insight into the MI-SF phase
transition process. Then by applying self-consistent approach to the method, we
include the effect of quantum and thermal fluctuations and derive the MI-SF
transition phase diagram, which is in quantitative agreement with recent
Monte-Carlo simulation at zero temperature, and at finite temperature, we find
the underestimation of finite-temperature-effect in the mean-field
approximation method. If we further consider the spin excitations in the
insulating states of spin-1 system in external field, distinct spin phases are
expected. Therefore, in the Mott lobes with and atoms per site, we
give analytical and numerical boundaries of the singlet, nematic, partially
magnetic and ferromagnetic phases in the magnetic phase diagrams.Comment: 14 pages, 6 figure
4-(4-Bromophenyl)-5-oxo-1,2,3,4,5,6,7,8-octahydroquinazoline-2-thione
The title compound, C14H13BrN2OS, was synthesized from the multicomponent reaction between thiourea, 4-bromobenzaldehyde and cyclohexane-1,3-dione. The crystal packing is stabilized by intermolecular N—H⋯O, N—H⋯S, C—H⋯O and C—H⋯S hydrogen bonds. Br⋯O interactions [3.183 (3) Å] are also observed in the crystal structure
(E)-2-(4-Fluorobenzylidene)cyclooctanone
The title compound, C15H17FO, was prepared directly from the aldol condensation of cyclooctanone with 4-fluorobenzaldehyde, catalysed by Pd(Ni,Ce) in the presence of trimethylsilyl chloride. The eight-membered ring adopts a boat-chair conformation
A conserved but plant-specific CDK-mediated regulation of DNA replication protein A2 in the precise control of stomatal terminal division
The R2R3-MYB transcription factor FOUR LIPS (FLP) controls the stomatal terminal division through transcriptional repression of the cell cycle genes CYCLIN-DEPENDENT KINASE (CDK) B1s (CDKB1s), CDKA; 1, and CYCLIN A2s (CYCA2s). We mutagenized the weak mutant allele flp-1 seeds with ethylmethane sulfonate and screened out a flp-1 suppressor 1 (fsp1) that suppressed the flp-1 stomatal cluster phenotype. FSP1 encodes RPA2a subunit of Replication Protein A (RPA) complexes that play important roles in DNA replication, recombination, and repair. Here, we show that FSP1/RPA2a functions together with CDKB1s and CYCA2s in restricting stomatal precursor proliferation, ensuring the stomatal terminal division and maintaining a normal guard-cell size and DNA content. Furthermore, we provide direct evidence for the existence of an evolutionarily conserved, but plant-specific, CDK-mediated RPA regulatory pathway. Serine-11 and Serine-21 at the N terminus of RPA2a are CDK phosphorylation target residues. The expression of the phosphorylation-mimic variant RPA2a(S11,21/D) partially complemented the defective cell division and DNA damage hypersensitivity in cdkb1;1 1;2 mutants. Thus, our study provides a mechanistic understanding of the CDK-mediated phosphorylation of RPA in the precise control of cell cycle and DNA repair in plants
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