4,083 research outputs found
A systematic review of the association between circulating concentrations of C reactive protein and cancer.
The objective of this study was to review and summarise the published evidence for an association between circulating concentrations of C reactive protein (CRP) and cancer through a systematic review. 90 discrete studies were identified. 81 (90%) were prevalent case-control or cross-sectional studies, and only 9 studies had a prospective design. In most prevalent studies, CRP concentrations were found to be higher in patients with cancer than in healthy controls or controls with benign conditions. Of the nine large prospective studies identified in this review, four reported no relationship between circulating CRP levels and breast, prostate or colorectal cancers, and five studies found that CRP was associated with colorectal or lung cancers. Most of the studies evaluating CRP as a diagnostic marker of cancer did not present relevant statistical analyses. Furthermore, any association reported in the prevalent studies might reflect reverse causation, survival bias or confounding. The prospective studies provided no strong evidence for a causal role of CRP in cancer. Instead of further prevalent studies, more large prospective studies and CRP gene-cancer association studies would be valuable in investigating the role of CRP in cancer
Huge thermoelectric effects in ferromagnet-superconductor junctions in the presence of a spin-splitting field
We show that a huge thermoelectric effect can be observed by contacting a
superconductor whose density of states is spin-split by a Zeeman field with a
ferromagnet with a non-zero polarization. The resulting thermopower exceeds
by a large factor, and the thermoelectric figure of merit can far
exceed unity, leading to heat engine efficiencies close to the Carnot limit. We
also show that spin-polarized currents can be generated in the superconductor
by applying a temperature bias.Comment: 5 pages, 4 figure
Physics of Proximity Josephson Sensor
We study the proximity Josephson sensor (PJS) in both bolometric and
calorimetric operation and optimize it for different temperature ranges between
25 mK and a few Kelvin. We investigate how the radiation power is absorbed in
the sensor and find that the irradiated sensor is typically in a weak
nonequilibrium state. We show in detail how the proximity of the
superconductors affects the device response: for example via changes in
electron-phonon coupling and out-of-equilibrium noise. In addition, we estimate
the applicability of graphene as the absorber material.Comment: 13 pages, 11 figures, submitted to Journal of Applied Physics, v2:
Addition of a new section discussing the radiation coupling to the device,
several minor change
Theory of temperature fluctuation statistics in superconductor-normal metal tunnel structures
We describe the statistics of temperature fluctuations in a SINIS structure,
where a normal metal island (N) is coupled by tunnel junctions (I) to two
superconducting leads (S). We specify conditions under which this structure
exhibits manifestly non-Gaussian fluctuations of temperature. We consider both
the Gaussian and non-Gaussian regimes of these fluctuations, and the current
fluctuations that are caused by the fluctuating temperature. We also describe a
measurement setup that could be used to observe the temperature fluctuations.Comment: 10 pages, 9 figures, final versio
Fully Overheated Single-Electron Transistor
We consider the fully overheated single-electron transistor, where the heat
balance is determined entirely by electron transfers. We find three distinct
transport regimes corresponding to cotunneling, single-electron tunneling, and
a competition between the two. We find an anomalous sensitivity to temperature
fluctuations at the crossover between the two latter regimes that manifests in
an exceptionally large Fano factor of current noise.Comment: 6 pages, 3 figures, includes Appendi
Absorption of heat into a superconductor-normal metal-superconductor junction from a fluctuating environment
We study a diffusive superconductor-normal metal-superconductor junction in
an environment with intrinsic incoherent fluctuations which couple to the
junction through an electromagnetic field. When the temperature of the junction
differs from that of the environment, this coupling leads to an energy transfer
between the two systems, taking the junction out of equilibrium. We describe
this effect in the linear response regime and show that the change in the
supercurrent induced by this coupling leads to qualitative changes in the
current-phase relation and for a certain range of parameters, an increase in
the critical current of the junction. Besides normal metals, similar effects
can be expected also in other conducting weak links.Comment: 5 pages, 4 figures - supplementary information included: 3 pages, 1
figure; minor modifications to the text and Fig. 2, added Ref. 1
High-temperature surface superconductivity in topological flat-band systems
We show that the topologically protected flat band emerging on a surface of a
nodal fermionic system promotes the surface superconductivity due to an
infinitely large density of states associated with the flat band. The critical
temperature depends linearly on the pairing interaction and can be thus
considerably higher than the exponentially small bulk critical temperature. We
discuss an example of surface superconductivity in multilayered graphene with
rhombohedral stacking
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