3,266 research outputs found
System design study for an optimal remote oculometer for use in operational aircraft
System design of optimal remote oculometer for use in operational aircraf
Editorial: maintaining open access to high quality publications at no cost to authors
The inability to access scientific literature freely can be a major obstacle in the advancement of science. Many reputable journals offering optional open access incur a substantial upfront payment to cover their publication costs, and hence many authors cannot afford to publish open access papers in a journal with an established reputation. Publishers charging for article processing claim that the charge is necessary to maintain their reputation and costs for peer review, editing and indexing articles. Thus, some open-access publications have a less rigorous peer-review and editorial process
Influence of spin waves on transport through a quantum-dot spin valve
We study the influence of spin waves on transport through a single-level
quantum dot weakly coupled to ferromagnetic electrodes with noncollinear
magnetizations. Side peaks appear in the differential conductance due to
emission and absorption of spin waves. We, furthermore, investigate the
nonequilibrium magnon distributions generated in the source and drain lead. In
addition, we show how magnon-assisted tunneling can generate a fullly
spin-polarized current without an applied transport voltage. We discuss the
influence of spin waves on the current noise. Finally, we show how the magnonic
contributions to the exchange field can be detected in the finite-frequency
Fano factor.Comment: published version, 15 pages, 10 figure
Energy transfer in nonlinear network models of proteins
We investigate how nonlinearity and topological disorder affect the energy
relaxation of local kicks in coarse-grained network models of proteins. We find
that nonlinearity promotes long-range, coherent transfer of substantial energy
to specific, functional sites, while depressing transfer to generic locations.
Remarkably, transfer can be mediated by the self-localization of discrete
breathers at distant locations from the kick, acting as efficient
energy-accumulating centers.Comment: 4 pages, 3 figure
Reflections on using student-authored questions to encourage learning in physics
In our previous work (Merchant and McGregor 2005) we outlined preliminary studies into the effectiveness of a teaching method designed to encourage students to pose their own questions as an assignment task. While the questions posed by students provide considerable feedback on their progress, several questions about the technique need to be answered: was the dialogue between students on a level where they were discussing true and accurate science? Apart from the first attempt, was the technique practical to implement for large classes? And finally, can this technique be useful in all years of a program? In this paper we provide a further analysis of the student discussions and how they relate to the questions posed, moreover how they relate to the objectives of the course. We will discuss modifications to the assessment task aimed both to reduce the administrative load in implementing the task and to encourage validation of the student discussions through self-moderation. Finally we propose a model for implementing the technique of student-authored questions at different year levels
Electrically Tunable Spin Polarization in a Carbon-Nanotube Spin Diode
We have studied the current through a carbon nanotube quantum dot with one
ferromagnetic and one normal-metal lead. For the values of gate voltage at
which the normal lead is resonant with the single available non-degenerate
energy level on the dot, we observe a pronounced decrease in the current for
one bias direction. We show that this rectification is spin-dependent, and that
it stems from the interplay between the spin accumulation and the Coulomb
blockade on the quantum dot. Our results imply that the current is
spin-polarized for one direction of the bias, and that the degree of spin
polarization is fully and precisely tunable using the gate and bias voltages.
As the operation of this spin diode does not require high magnetic fields or
optics, it could be used as a building block for electrically controlled
spintronic devices.Comment: 17 pages, 4 figure
Clinical translation of [18F]ICMT-11 for measuring chemotherapy-induced caspase 3/7 activation in breast and lung cancer
Background: Effective anticancer therapy is thought to involve induction of tumour cell death through apoptosis and/or necrosis. [18F]ICMT-11, an isatin sulfonamide caspase-3/7-specific radiotracer, has been developed for PET imaging and shown to have favourable dosimetry, safety, and biodistribution. We report the translation of [18F]ICMT-11 PET to measure chemotherapy-induced caspase-3/7 activation in breast and lung cancer patients receiving first-line therapy. Results: Breast tumour SUVmax of [18F]ICMT-11 was low at baseline and unchanged following therapy. Measurement of M30/M60 cytokeratin-18 cleavage products showed that therapy was predominantly not apoptosis in nature. While increases in caspase-3 staining on breast histology were seen, post-treatment caspase-3 positivity values were only approximately 1%; this low level of caspase-3 could have limited sensitive detection by [18F]ICMT-11-PET. Fourteen out of 15 breast cancer patients responded to first–line chemotherapy (complete or partial response); one patient had stable disease. Four patients showed increases in regions of high tumour [18F]ICMT-11 intensity on voxel-wise analysis of tumour data (classed as PADS); response was not exclusive to patients with this phenotype. In patients with lung cancer, multi-parametric [18F]ICMT-11 PET and MRI (diffusion-weighted- and dynamic contrast enhanced-MRI) showed that PET changes were concordant with cell death in the absence of significant perfusion changes. Conclusion: This study highlights the potential use of [18F]ICMT-11 PET as a promising candidate for non-invasive imaging of caspase3/7 activation, and the difficulties encountered in assessing early-treatment responses. We summarize that tumour response could occur in the absence of predominant chemotherapy-induced caspase-3/7 activation measured non-invasively across entire tumour lesions in patients with breast and lung cancer
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