2,599 research outputs found
Periodic Oscillations of Josephson-Vortex Flow Resistance in Oxygen-Deficient Y1Ba2Cu3Ox
We measured the Josephson vortex flow resistance as a function of magnetic
field applied parallel to the ab-planes using annealed Y1Ba2Cu3Ox intrinsic
Josephson junctions having high anisotropy (around 40) by oxygen content
reduction. Periodic oscillations were observed in magnetic fields above 45-58
kOe, corresponding to dense-dilute boundary for Josephson vortex lattice. The
observed period of oscillations, agrees well with the increase of one fluxon
per two junctions (\textit{=}\textit{/2Ls}), may correspond
to formation of a triangular lattice of Josephson vortices as has been reported
by Ooi et al. for highly anisotropic (larger than 200) Bi-2212 intrinsic
Josephson junctions.Comment: 5 pages, 4 figure
Anisotropic Superconducting Properties of MgB2 Single Crystals
In-plane electrical transport properties of MgB2 single crystals grown under
high pressure of 4-6 GPa and temperature of 1400-1700oC in Mg-B-N system have
been measured. For all specimens we found sharp superconducting transition
around 38.1-38.3K with transition width within 0.2-0.3K. Estimated resistivity
value at 40K is about 1 mkOhmcm and resistivity ratio R(273K)/R(40K) of about
4.9. Results of measurements in magnetic field up to 5.5T perpendicular to Mg
and B planes and up to 9T in parallel orientation show temperature dependent
anisotropy of the upper critical field with anisotropy ratio increasing from
2.2 close to Tc up to about 3 below 30K. Strong deviation of the angular
dependence of Hc2 from anisotropic mass model has been also found.Comment: 10pages, including 5 figures,submitted to Physica C (in press
Comprehensive Analysis of NAC Transcription Factor Family Uncovers Drought and Salinity Stress Response in Pearl Millet (\u3cem\u3ePennisetum glaucum\u3c/em\u3e)
BACKGROUND: Pearl millet (Pennisetum glaucum) is a cereal crop that possesses the ability to withstand drought, salinity and high temperature stresses. The NAC [NAM (No Apical Meristem), ATAF1 (Arabidopsis thaliana Activation Factor 1), and CUC2 (Cup-shaped Cotyledon)] transcription factor family is one of the largest transcription factor families in plants. NAC family members are known to regulate plant growth and abiotic stress response. Currently, no reports are available on the functions of the NAC family in pearl millet.
RESULTS: Our genome-wide analysis found 151 NAC transcription factor genes (PgNACs) in the pearl millet genome. Thirty-eight and 76 PgNACs were found to be segmental and dispersed duplicated respectively. Phylogenetic analysis divided these NAC transcription factors into 11 groups (A-K). Three PgNACs (− 073, − 29, and − 151) were found to be membrane-associated transcription factors. Seventeen other conserved motifs were found in PgNACs. Based on the similarity of PgNACs to NAC proteins in other species, the functions of PgNACs were predicted. In total, 88 microRNA target sites were predicted in 59 PgNACs. A previously performed transcriptome analysis suggests that the expression of 30 and 42 PgNACs are affected by salinity stress and drought stress, respectively. The expression of 36 randomly selected PgNACs were examined by quantitative reverse transcription-PCR. Many of these genes showed diverse salt- and drought-responsive expression patterns in roots and leaves. These results confirm that PgNACs are potentially involved in regulating abiotic stress tolerance in pearl millet.
CONCLUSION: The pearl millet genome contains 151 NAC transcription factor genes that can be classified into 11 groups. Many of these genes are either upregulated or downregulated by either salinity or drought stress and may therefore contribute to establishing stress tolerance in pearl millet
(3R,6R,12R,20S,24R)-20,24-Epoxydammarane-3,6,12,25-tetraol
In the title compound, C30H52O5, the three six-membered rings are in chair conformations, the five-membered ring is in an envelope form and the tetrahydrofuran ring has a conformation intermediate between half-chair and sofa. Intramolecular O—H⋯O hydrogen bonds may influence the conformation of the molecule. In the crystal, molecules are linked by intermolecular O—H⋯O hydrogen bonds, forming a three-dimensional network
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