1,270 research outputs found
Quantum information processing using Josephson junctions coupled through cavities
Josephson junctions have been shown to be a promising solid-state system for
implementation of quantum computation. The significant two-qubit gates are
generally realized by the capacitive coupling between the nearest neighbour
qubits. We propose an effective Hamiltonian to describe charge qubits coupled
through the cavity. We find that nontrivial two-qubit gates may be achieved by
this coupling. The ability to interconvert localized charge qubits and flying
qubits in the proposed scheme implies that quantum network can be constructed
using this large scalable solid-state system.Comment: 5 pages, to appear in Phys Rev A; typos corrected, solutions in last
eqs. correcte
Triggers and cues that activate antibiotic production by actinomycetes
Microbial Biotechnolog
Intertwined Precursor Supply during Biosynthesis of the Catecholate-Hydroxamate Siderophores Qinichelins in Streptomyces sp MBT76
Bio-organic SynthesisMicrobial Biotechnolog
Genetic partitioning of interleukin-6 signalling in mice dissociates Stat3 from Smad3-mediated lung fibrosis
Idiopathic pulmonary fibrosis (IPF) is a fatal disease that is unresponsive to current therapies and characterized by excessive collagen deposition and subsequent fibrosis. While inflammatory cytokines, including interleukin (IL)-6, are elevated in IPF, the molecular mechanisms that underlie this disease are incompletely understood, although the development of fibrosis is believed to depend on canonical transforming growth factor (TGF)-β signalling. We examined bleomycin-induced inflammation and fibrosis in mice carrying a mutation in the shared IL-6 family receptor gp130. Using genetic complementation, we directly correlate the extent of IL-6-mediated, excessive Stat3 activity with inflammatory infiltrates in the lung and the severity of fibrosis in corresponding gp130757F mice. The extent of fibrosis was attenuated in B lymphocyte-deficient gp130757F;µMT−/− compound mutant mice, but fibrosis still occurred in their Smad3−/− counterparts consistent with the capacity of excessive Stat3 activity to induce collagen 1α1 gene transcription independently of canonical TGF-β/Smad3 signalling. These findings are of therapeutic relevance, since we confirmed abundant STAT3 activation in fibrotic lungs from IPF patients and showed that genetic reduction of Stat3 protected mice from bleomycin-induced lung fibrosis
Accelerating Neoproterozoic research through scientific drilling
No abstract available
Insulating and Conducting Phases of RbC60
Optical measurements were performed on thin films of RbC,
identified by X-ray diffraction as mostly material. The samples were
subjected to various heat treatments, including quenching and slow cooling from
400K. The dramatic increase in the transmission of the quenched samples, and
the relaxation towards the transmission observed in slow cooled samples
provides direct evidence for the existence of a metastable insulating phase.
Slow cooling results in a phase transition between two electrically conducting
phases.Comment: Minor revisions. Submitted to PRB, RevTeX 3.0 file, 2 postscript
figures included, ir_dop
Retention of Supraspinal Delta-like Analgesia and Loss of Morphine Tolerance in δ Opioid Receptor Knockout Mice
AbstractGene targeting was used to delete exon 2 of mouse DOR-1, which encodes the δ opioid receptor. Essentially all 3H-[D-Pen2,D-Pen5]enkephalin (3H-DPDPE) and 3H-[D-Ala2,D-Glu4]deltorphin (3H-deltorphin-2) binding is absent from mutant mice, demonstrating that DOR-1 encodes both δ1 and δ2 receptor subtypes. Homozygous mutant mice display markedly reduced spinal δ analgesia, but peptide δ agonists retain supraspinal analgesic potency that is only partially antagonized by naltrindole. Retained DPDPE analgesia is also demonstrated upon formalin testing, while the nonpeptide δ agonist BW373U69 exhibits enhanced activity in DOR-1 mutant mice. Together, these findings suggest the existence of a second delta-like analgesic system. FinallyDOR-1 mutant mice do not develop analgesic tolerance to morphine, genetically demonstrating a central role for DOR-1 in this process
A universal Hamiltonian for the motion and the merging of Dirac cones in a two-dimensional crystal
We propose a simple Hamiltonian to describe the motion and the merging of
Dirac points in the electronic spectrum of two-dimensional electrons. This
merging is a topological transition which separates a semi-metallic phase with
two Dirac cones from an insulating phase with a gap. We calculate the density
of states and the specific heat. The spectrum in a magnetic field B is related
to the resolution of a Schrodinger equation in a double well potential. They
obey the general scaling law e_n \propto B^{2/3} f_n(Delta /B^{2/3}. They
evolve continuously from a sqrt{n B} to a linear (n+1/2)B dependence, with a
[(n+1/2)B]^{2/3} dependence at the transition. The spectrum in the vicinity of
the topological transition is very well described by a semiclassical
quantization rule. This model describes continuously the coupling between
valleys associated with the two Dirac points, when approaching the transition.
It is applied to the tight-binding model of graphene and its generalization
when one hopping parameter is varied. It remarkably reproduces the low field
part of the Rammal-Hofstadter spectrum for the honeycomb lattice.Comment: 18 pages, 15 figure
Analysis of novel kitasatosporae reveals significant evolutionary changes in conserved developmental genes between Kitasatospora and Streptomyces
Microbial Biotechnolog
- …