539 research outputs found
High fidelity state preparation, quantum control, and readout of an isotopically enriched silicon spin qubit
Quantum systems must be prepared, controlled, and measured with high fidelity
in order to perform complex quantum algorithms. Control fidelities have greatly
improved in silicon spin qubits, but state preparation and readout fidelities
have generally been poor. By operating with low electron temperatures and
employing high-bandwidth cryogenic amplifiers, we demonstrate single qubit
readout visibilities >99%, exceeding the threshold for quantum error
correction. In the same device, we achieve average single qubit control
fidelities >99.95%. Our results show that silicon spin qubits can be operated
with high overall operation fidelity
Stationkeeping, Orbit Determination, and Attitude Control for Spacecraft in Near Rectilinear Halo Orbits
Final document is attached. From a Near Rectilinear Halo Orbit (NRHO), NASA's Gateway at the Moon is planned to serve as a proving ground and a staging location for human missions beyond Earth. Stationkeeping, Orbit Determination (OD), and attitude control are examined for uncrewed and crewed Gateway configurations. Orbit maintenance costs are investigated using finite maneuvers, considering skipped maneuvers and perturbations. OD analysis assesses DSN tracking and identifies OD challenges associated with the NRHO and crewed operations. The Gateway attitude profile is simulated to determine an effective equilibrium attitude. Attitude control propellant use and sizing of the required passive attitude control system are assessed
Emerging therapies for noninfectious uveitis: what may be coming to the clinics.
Corticosteroids along with other immunomodulatory therapies remain as the mainstay of treatment tor all patients with noninfectious uveitis (NIU). However, the systemic side effects associated with the long-term use of these drugs has encouraged the development of new therapeutic agents in recent times. This review article discusses upcoming therapeutic agents and drug delivery systems that are currently being used to treat patients with NIU. These agents mediate their actions by blocking specific pathways involved in the inflammatory process. Agents discussed in this review include full or recombinant monoclonal antibodies against interleukins such as IL-17 (secukinumab), IL-l (gevokizumab), and IL-6 (tocilizumab and sarilumab), antibody fragments against inflammatory cytokines such as TNF- α (ESBA 105) and T-cell inhibitors such as fusion proteins (abatacept), and next generation calcineurin inhibitors (voclosporin). In addition, administration of immune modulatory therapies using methods such as iontophoresis (EGP-437) and intravitreal injection (sirolimus) for the treatment of NIU\u27 uveitis has also been discussed
Identification of new drug targets and resistance mechanisms in Mycobacterium tuberculosis
Identification of new drug targets is vital for the advancement of drug discovery against Mycobacterium tuberculosis , especially given the increase of resistance worldwide to first- and second-line drugs. Because traditional target-based screening has largely proven unsuccessful for antibiotic discovery, we have developed a scalable platform for target identification in M. tuberculosis that is based on whole-cell screening, coupled with whole-genome sequencing of resistant mutants and recombineering to confirm. The method yields targets paired with whole-cell active compounds, which can serve as novel scaffolds for drug development, molecular tools for validation, and/or as ligands for co-crystallization. It may also reveal other information about mechanisms of action, such as activation or efflux. Using this method, we identified resistance-linked genes for eight compounds with anti-tubercular activity. Four of the genes have previously been shown to be essential: AspS, aspartyl-tRNA synthetase, Pks13, a polyketide synthase involved in mycolic acid biosynthesis, MmpL3, a membrane transporter, and EccB3, a component of the ESX-3 type VII secretion system. AspS and Pks13 represent novel targets in protein translation and cell-wall biosynthesis. Both MmpL3 and EccB3 are involved in membrane transport. Pks13, AspS, and EccB3 represent novel candidates not targeted by existing TB drugs, and the availability of whole-cell active inhibitors greatly increases their potential for drug discovery
Quasinormal Modes of Dirty Black Holes
Quasinormal mode (QNM) gravitational radiation from black holes is expected
to be observed in a few years. A perturbative formula is derived for the shifts
in both the real and the imaginary part of the QNM frequencies away from those
of an idealized isolated black hole. The formulation provides a tool for
understanding how the astrophysical environment surrounding a black hole, e.g.,
a massive accretion disk, affects the QNM spectrum of gravitational waves. We
show, in a simple model, that the perturbed QNM spectrum can have interesting
features.Comment: 4 pages. Published in PR
- …