A fully integrated direct-conversion tuner is implemented in 0.13 mu m CMOS technology. A broadband noise-canceling balun LNA with the proposed dual cross-coupling technique helps achieve an overall receiver noise figure from 3.7 to 4.3 dB while consuming only 3.6 mW. The proposed current-mode switching scheme improves the achievable SNIR with a gain step of 15 dB, providing IIP3 improvement of 18 dB and NF degradation of only 6 dB. Moreover, design trade-offs are carefully considered in designing the baseband circuit, which provides wide gain tuning and bandwidth accuracy with a DC offset residual less than 6 mV. The measured maximum SNR values are better than 30 dB over wide input power levels, ensuring robust reception in a mobile environment. All circuit blocks are operated at 1.2 V. As a result, the tuner consumes power as low as 114 mW in the continuous mode. This compact tuner supports both UHF and L-bands, and occupies only 7.2 mm(2) die area.
Verbrugghe, P.
Waelput, W.
Dieriks, B.
Waeytens, A.
Vandesompele, J.
Cuvelier, C. A.
The specialized epithelium covering the lymphoid follicles of Peyer's patches in the gut mediates transcytosis membranou immune res and M cells anscytosis of antigens to the underlying immune cells, mainly through the or M, cells. At present, the molecular processes involved in the mucosal reponse, and in antigen transport across the follicle-associated epithelium (FAE), are poorly understood. To characterize FAE and M cells, we compared the gene expression profiles of small intestine FAE and villus epithelium (VE) in BALB/c mice by microarray analysis; 91 genes were found to be up-regulated and four down-regulated at least two-fold (p < 0.01) in the FAE. The differential expression of a subset of these genes was shown to be confirmed by quantitative RT-PCR. Using immunohistochemistry on BALB/c Peyer's patches, cathepsin H and clusterin expression was increased in the FAE compared to the VE. Moreover, we demonstrated M cell-specific expression of annexin V, which has recently been reported to be important in endocytic transport and membrane scaffolding, suggesting that annexin V has a function in M cell-mediated transcytosis. Copyright (c) 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
In this paper, we present a theoretical study of magnetic properties of MPo (M=Ti, V, Cr, Mn, Fe) compounds in the zinc-blend structure using full-potential linear augmented plane wave method. Our calculation indicates that MnPo and FePo are antiferromagnetic, whereas TiPo, VPo, and CrPo are magnetic. The ferromagnetic phase is enhanced with decreasing lattice constant and increasing atomic number along the sequence TiPo -> VPo -> CrPo. TiPo, VPo, and CrPo are predicted to be half-metal ferromagnetic with magnetic moments of 2.0 mu(B), 3.0 mu(B), and 4.0 mu(B), respectively, which is confirmed from the calculated minority (majority) spin channel band structure showing the semiconducting (metallic) behavior of these compounds. The magnetism comes essentially from the d orbital of Ti, V, and Cr atoms. In addition, we have found that half-metallicity can be maintained even when spin-orbit interaction is included for TiPo and VPo. However spin-orbit effect destroys magnetism in CrPo.
Low input-referred offset performance and linearity in analog filters are critical design parameters, yet transistor mismatch limitations are a severe hindrance. Programmability is also a feature of growing significance because high performance state-of-the-art systems must adapt on-the-fly to various operating conditions, as is the case in battery-operated electronics where systems traverse through idle, alert, and high performance modes in an effort to conserve energy and extend battery life. This paper presents a continuous and programmable first-order G(m)-C filter with sub-millivolt offset performance. Low offset is achieved by auto-zeroing and continuity by ping-ponging between two transconductors, all under the construct of a compact and bandwidth-efficient circuit topology. The proposed G(m)-C circuit was fabricated with AMI's 0.5-mu m CMOS process technology and achieved an input-referred offset of less than 210 mu V, hand-over glitches of less than 40 mV, and 57 dB of linearity over the rail-to-rail input span for a lithium-ion battery supply range of 3 to 4.2 V. The bandwidth and gain of the filter were programmable from 1.1 to 6.5 kHz and 1.27 to 29.1 V/V, respectively, both with better than 3.2% resolution.
We study the magnetic properties of M-doped (M = Ti,V,Cr) (GaN), (x <= 3) clusters using the first principles of density functional theory (DFT). Our calculations reveal that although the magnetic coupling between M atoms is ferromagnetic (with total magnetic moments ranging from 0 to 10 mu(B)), the antiferromagnetic arrangements are favored for these clusters. Spin density analysis reveals that the stabilization of the antiferromagnetic phase is caused by the antiferromagnetic coupling between the d-states of M atoms and the p-states of N atoms. This also makes the M atoms tend to bind more strongly to N atoms than to Ga atoms. This study may explain the role of the anions in diluted magnetic semiconductors (DMS). (c) 2006 Elsevier B.V. All rights reserved.
The valence photoabsorption spectra of the series of the monoanionic closed shell icosahedral clusters with M = V, Nb and Ta have been calculated with the time-dependent density functional theory (TDDFT), employing the zero-order regular approximation (ZORA) at both scalar relativistic and spin–orbit coupling levels. The calculated photoabsorption spectra show interesting variations according to the nature of the encapsulated metal atom. Spin–orbit coupling plays an important role in these systems. The comparison with the neutral isoelectronic clusters WAu12 and MoAu12 suggests a curious relationship along the diagonal of the periodic table.