62 research outputs found
Comprehensive characterization of molecular interactions based on nanomechanics
Molecular interaction is a key concept in our understanding of the biological mechanisms of life. Two physical properties change when one molecular partner binds to another. Firstly, the masses combine and secondly, the structure of at least one binding partner is altered, mechanically transducing the binding into subsequent biological reactions. Here we present a nanomechanical micro-array technique for bio-medical research, which not only monitors the binding of effector molecules to their target but also the subsequent effect on a biological system in vitro. This label-free and real-time method directly and simultaneously tracks mass and nanomechanical changes at the sensor interface using micro-cantilever technology. To prove the concept we measured lipid vesicle (approximately 748*10(6) Da) adsorption on the sensor interface followed by subsequent binding of the bee venom peptide melittin (2840 Da) to the vesicles. The results show the high dynamic range of the instrument and that measuring the mass and structural changes simultaneously allow a comprehensive discussion of molecular interactions
Left-handed color-sextet diquark in Kaon system
We investigate whether a color-sextet scalar diquark () coupling
to the left-handed quarks contributes to the process. It is found
that the box diagrams mediated by and bosons have no
contributions to when the limit of is used, and the flavor
mixing matrices for diagonalizing quark mass matrices are introduced at the
same time. When the heavy top-quark mass effects are taken into account, it is
found that in addition to the box diagrams significantly
contributing to , their effects can be as large as those from the
box diagrams. Using the parameters that are constrained
by the mixing parameter and the Kaon indirect CP
violation , we find that the left-handed color-sextet diquark can
lead to the Kaon direct CP violation being . In the chosen scheme, although the diquark contribution to
is small, the branching ratio of can reach the current experimental upper bound.Comment: 22 pages, 6 figure
Coexistence of magnetism and superconductivity in separate layers of the iron-based superconductor
The magnetic properties attributed to the hydroxide layer of Li1-xFex(OH)Fe1-ySe have been elucidated by the study of superconducting and nonsuperconducting members of this family of compounds. Both ac magnetometry and muon spin relaxation measurements of nonsuperconductors find a magnetic state existing below ≈10 K which exhibits slow relaxation of magnetization. This magnetic state is accompanied by a low-temperature heat capacity anomaly present in both superconducting and nonsuperconducting variants suggesting that the magnetism persists into the superconducting state. The estimated value of magnetic moment present within the hydroxide layer supports a picture of a glassy magnetic state, probably comprising clusters of iron ions of varying cluster sizes distributed within the lithium hydroxide layer
Robustness of superconductivity to competing magnetic phases in tetragonal FeS
We have determined the superconducting and magnetic properties of a hydrothermally synthesized powder sample of tetragonal FeS using muon spin rotation (μSR). The superconducting properties are entirely consistent with those of a recently published study, showing fully gapped behavior and giving a penetration depth of λab=204(3) nm. However, our zero-fieldμSR data are rather different and indicate the presence of a small, nonsuperconducting magnetic phase within the sample. These results highlight that sample-to-sample variations in magnetism can arise in hydrothermally prepared phases, but interestingly the superconducting behavior is remarkably insensitive to these variations
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