269 research outputs found
Fermiology and superconductivity studies on the non-tetrachalcogenafulvalene structured organic superconductor beta-(BDA-TTP)_2SbF_6
The quantum oscillatory effect and superconductivity in a
non-tetrachalcogenafulvalene (TCF) structure based organic superconductor
beta-(BDA-TTP)_2SbF_6 are studied. Here the Shubnikov-de Haas effect (SdH) and
angular dependent magnetoresistance oscillations (AMRO) are observed. The
oscillation frequency associated with a cylindrical Fermi surface is found to
be about 4050 tesla, which is also verified by the tunnel diode oscillator
(TDO) measurement. The upper critical field Hc2 measurement in a tilted
magnetic field and the TDO measurement in the mixed state reveal a highly
anisotropic superconducting nature in this material. We compared physical
properties of beta-(BDA-TTP)_2SbF_6 with typical TCF structure based quasi
two-dimensional organic conductors. A notable feature of beta-(BDA-TTP)_2SbF_6
superconductor is a large value of effective cyclotron mass m_c^*=12.4+/1.1
m_e, which is the largest yet found in an organic superconductor. A possible
origin of the enhanced effective mass and its relation to the superconductivity
are briefly discussed.Comment: 8 pages, 10 figure
Highly active promoters and native secretion signals for protein production during extremely low growth rates in Aspergillus niger
Microbial Biotechnolog
Self-assembly of micelles into designed networks
The EO20PO70EO20(molecular weight 5800) amphiphile as a template is to form dispersed micelle structures. Silver nanoparticles, as inorganic precursors synthesized by a laser ablation method in pure water, are able to produce the highly ordered vesicles detected by TEM micrography. The thickness of the outer layer of a micelle, formed by the silver nanoparticles interacting preferentially with the more hydrophilic EO20block, was around 3.5 nm. The vesicular structure ensembled from micelles is due to proceeding to the mixture of cubic and hexagonal phases
Interplane Transport and Superfluid Density in Layered Superconductors
We report on generic trends in the behavior of the interlayer penetration
depth of several different classes of quasi two-dimensional
superconductors including cuprates, SrRuO, transition metal
dichalcogenides and organic materials of the -series. Analysis
of these trends reveals two distinct patterns in the scaling between the values
of and the magnitude of the DC conductivity: one realized in the
systems with a Fermi liquid (FL) ground state and the other seen in systems
with a marked deviation from the FL response. The latter pattern is found
primarily in under-doped cuprates and indicates a dramatic enhancement (factor
) of the energy scale associated with the formation of
the condensate compared to the data for the FL materials. We discuss
implications of these results for the understanding of pairing in high-
cuprates.Comment: 4 pages, 2 figure
Paramagnetic limiting of the upper critical field of the layered organic superconductor
We report detailed measurements of the interlayer magnetoresistance of the
layered organic superconductor for temperatures
down to 0.5 K and fields up to 30 tesla. The upper critical field is determined
from the resistive transition for a wide range of temperatures and field
directions. For magnetic fields parallel to the layers, the upper critical
field increases approximately linearly with decreasing temperature. The upper
critical field at low temperatures is compared to the Pauli paramagnetic limit,
at which singlet superconductivity should be destroyed by the Zeeman splitting
of the electron spins. The measured value is comparable to a value for the
paramagnetic limit calculated from thermodynamic quantities but exceeds the
limit calculated from BCS theory. The angular dependence of the upper critical
field shows a cusp-like feature for fields close to the layers, consistent with
decoupled layers.Comment: 16 pages 5 figure
DNA Damage during G2 Phase Does Not Affect Cell Cycle Progression of the Green Alga Scenedesmus quadricauda
DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency for photosynthesis. For survival of a plant, and other eukaryotic cells, it is essential for an organism to continuously check the integrity of its genetic material and, when damaged, to repair it immediately. Cells therefore utilize a DNA damage response pathway that is responsible for sensing, reacting to and repairing damaged DNA. We have studied the effect of 5-fluorodeoxyuridine, zeocin, caffeine and combinations of these on the cell cycle of the green alga Scenedesmus quadricauda. The cells delayed S phase and underwent a permanent G2 phase block if DNA metabolism was affected prior to S phase; the G2 phase block imposed by zeocin was partially abolished by caffeine. No cell cycle block was observed if the treatment with zeocin occurred in G2 phase and the cells divided normally. CDKA and CDKB kinases regulate mitosis in S. quadricauda; their kinase activities were inhibited by Wee1. CDKA, CDKB protein levels were stabilized in the presence of zeocin. In contrast, the protein level of Wee1 was unaffected by DNA perturbing treatments. Wee1 therefore does not appear to be involved in the DNA damage response in S. quadricauda. Our results imply a specific reaction to DNA damage in S. quadricauda, with no cell cycle arrest, after experiencing DNA damage during G2 phase
Synthesis of Highly Substituted Adamantanones from Bicyclo[3.3.1]nonanes
Trifluoromethanesulfonic acid and other electrophiles promote formation of the adamantanone core from the readily accessible 1,5-dimethyl-3,7-dimethylenebicyclo[3.3.1]nonan-9-one 2. Because adamantyl cation 3 can be trapped by a range of nucleophiles, including aromatic and heteroaromatic rings, alcohol, nitriles, and halides, access to a wide variety of functionality at the newly formed tertiary position is provided
Functional-Aspects of the Nuclear Matrix
Contains fulltext :
28808.pdf (publisher's version ) (Open Access
Cellular organelle transport and positioning by plasma streaming
Contains fulltext :
129298.pdf (publisher's version ) (Open Access
- …