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High-performance InSb micro-Hall sensors were fabricated by optical lithography and incorporated in a room-temperature scanning Hall probe microscope for imaging of localized magnetic fluctuations in close proximity to the surfaces of crystalline uniaxial garnet films. The room-temperature noise figure of the InSb sensors was 6-10 mG/[square root of (Hz)], which is an order of magnitude better than GaAs-AlGaAs two-dimensional electron gas sensors used to date. Index Terms--Hall effect, scanning Hall probe microscopy.

The magnetoresistive properties of micro-Hall devices fabricated by using InAlSb/InAsSb/InAlSb heterostructures are described where electrical conduction is confined to a 30 nm-InAs two-dimensional electron gas layer. Photolithography is used for preparing Hall probes, which are installed into a scanning Hall probe microscope and are used for imaging the surface of a hard disk.

Objective Pro-brain natriuretic peptide (proBNP)-108 and N-terminal proBNP-76 (NT-BNP) contain seven sites for O-linked oligosaccharide attachment. Currently, levels of glycosylated NT-BNP are probably underestimated because it is not recognised by one antibody in the sandwich assay system. The pathophysiological significance of cardiac and plasma levels of non-glycosylated (nonglyNT-BNP) and glycosylated NT-BNP (glyNT-BNP) in heart failure (HF) and chronic renal failure (CRF) was investigated. Methods Plasma samples from 186 patients with HF and 76 patients with CRF on haemodialysis were studied, together with 11 atrial tissue samples. To measure nonglyNT-BNP and glyNT-BNP, samples were incubated with or without deglycosylating enzymes and NT-BNP was measured using Roche Elecsys proBNP I. The percentage glyNT-BNP was calculated as glyNT-BNP/(glyNT-BNP + nonglyNT-BNP). Results In HF, plasma BNP, nonglyNT-BNP and glyNT-BNP levels all increased with increasing disease severity (New York Heart Association class; p<0.0001), though the molar ratio remained constant (molar ratio, BNP:nonglyNT-BNP:glyNT-BNP = 1:2.4:9.6). Before haemodialysis for CRF, plasma BNP and nonglyNT-BNP were somewhat elevated, and glyNT-BNP was markedly increased (molar ratio, BNP:nonglyNT-BNP:glyNT-BNP = 1:8.5:82). After haemodialysis, plasma BNP, nonglyNT-BNP, atrial natriuretic protein and cGMP all declined (p<0.0001), but glyNT-BNP was unchanged. Notably, the percentage of glyNT-BNP was elevated before haemodialysis, and was further increased after haemodialysis (p<0.0001). Atrial tissue levels of BNP, nonglyNT-BNP and glyNT-BNP were similar. Conclusion The findings suggest that most endogenous plasma NT-BNP is glycosylated and therefore undetectable with the current assay system, and that the relative glycosylation level is increased by haemodialysis. [ABSTRACT FROM AUTHOR]

Abstract: We examined the role of localized electrons in the accumulation layer of Sn-doped InSb quantum wells (QWs) with various wellwidths . At liquid He temperatures, the samples with the sheet resistance for exhibit the variable-range hopping (VRH), while those with exhibit weak localization (WL), where is the quantum resistance. In particular, a part of the electrons (with density of ) from Sn donors are trapped at the interface states at low temperatures below 77 K. In the WL regime, we observed the small positive magnetoresistance (MR) peak arising from the weak anti-localization (WAL) in the presence of spin-orbit interaction (SOI). In contrast to the WAL in WL regime, the low-field MR in the VRH regime remains entirely negative surviving the SOI, indicating that the hopping MR due to the quantum interference (QI) is completely negative regardless of the SOI. This result supports the predictions based on the directed-path approach for forward-scattering paths ignoring the back-scattering return loops for the QI in the VRH. [Copyright &y& Elsevier]

We have investigated magneto-resistance in InAs/Al0.6Ga0.4As0.1Sb0.9 quantum well (QW), where the lattice mismatch at the interface is less than 2 %. The carrier concentration can be tuned by using positive and negative persistent photoconductivity effect, selected by the wavelength (λ=1.6μm or 0.95 μm) of illumination. The electrons and holes coexist in the QW structure, and the contribution of both carriers should be taken into account. The observed deviation of Hall plateaus from the quantized value can be understood by considering the carrier transport in both electron and hole edge channels, and the equilibrium of chemical potential at the all electrodes in the sample. The transport properties in quantum Hall regime measured in the samples with the QW thickness of 15, 50 and 150 nm are reported. [ABSTRACT FROM AUTHOR]