An ultra-wideband 3.1-10.6-GHz low-noise amplifier employing a broadband noise-canceling technique is presented. By using the proposed circuit and design methodology, the noise from the matching device is greatly suppressed over the desired UWB band, while the noise from other devices performing noise cancellation is minimized by the systematic approach. Fabricated in a 0.18-m CMOS process, the IC prototype achieves a power gain of 9.7 dB over a 3 dB bandwidth of 1.2-11.9-GHz and a noise figure of 4.5-5.1 dB in the entire UWB band. It consumes 20 mW from a 1.8-V supply and occupies an area of only 0.59 mm 2 .Index Terms-Broadband, low-noise amplifier (LNA), noise canceling, ultra-wideband (UWB).

Four new compounds, including three new benzenoids, antrocamphin A (1), antrocamphin B (2), and 2,3,4,5-tetramethoxybenzoyl chloride (3), and a new 1,3-dioxolan-2-one derivative, antrodioxolanone (4), together with 13 known compounds have been isolated from the fruiting body of Antrodia camphorata. The structures of these new compounds were determined through spectral analyses including extensive 2D-NMR data. Among the isolates, antrocamphin A (1), antcin A (10), and antcin B (11) exhibited potent inhibition against fMLP-induced superoxide production with IC50 values less than 10 microM.

Sphingosine 1-phosphate (S1P) has been shown to regulate smooth muscle cell proliferation, migration, and vascular maturation. S1P increases the expression of several proteins including COX-2 in vascular smooth muscle cells (VSMCs) and contributes to arteriosclerosis. However, the mechanisms regulating COX-2 expression by S1P in VSMCs remain unclear. Western blotting and RT-PCR analyses showed that S1P induced the expression of COX-2 mRNA and protein in a time- and concentration-dependent manner, which was attenuated by inhibitors of MEK1/2 (U0126) and PI3K (wortmannin), and transfection with dominant negative mutants of p42/p44 mitogen-activated protein kinases (ERK2) or Akt. These results suggested that both p42/p44 MAPK and PI3K/Akt pathways participated in COX-2 expression induced by S1P in VSMCs. In accordance with these findings, S1P stimulated phosphorylation of p42/p44 MAPK and Akt, which was attenuated by U0126, LY294002, or wortmannin, respectively. Furthermore, this up-regulation of COX-2 mRNA and protein was blocked by a selective NF-kappaB inhibitor helenalin. Consistently, S1P-stimulated translocation of NF-kappaB into the nucleus was revealed by immnofluorescence staining. Moreover, S1P-stimulated activation of NF-kappaB promoter activity was blocked by phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and helenalin, but not by U0126, suggesting that involvement of PI3K/Akt in the activation of NF-kappaB. COX-2 promoter assay showed that S1P induced COX-2 promoter activity mediated through p42/p44 MAPK, PI3K/Akt, and NF-kappaB. These results suggested that in VSMCs, activation of p42/p44 MAPK, Akt and NF-kappaB pathways was essential for S1P-induced COX-2 gene expression. Understanding the mechanisms involved in S1P-induced COX-2 expression on VSMCs may provide potential therapeutic targets in the treatment of arteriosclerosis.

Disabled-2 (DAB2) is an adapter protein that is up-regulated during megakaryocytic differentiation of hematopoietic cells and is abundantly expressed in platelets. In this study, the role of DAB2 in integrin ␣ IIb ␤ 3 -mediated matrix protein fibrinogen adhesion and cell signaling was investigated. In K562 cells differentiating to the megakaryocytic lineage, down-regulation of DAB2 by DAB2 small interfering RNA augmented integrin ␣ IIb ␤ 3 activation and resulted in an increase in cell adhesion to fibrinogen. Ectopic expression of DAB2 reversed the DAB2 small interfering RNA effect or, by itself, decreased fibrinogen adhesion of K562 cells. Mutational analysis revealed that a DAB2 Ser 24 phosphorylation mutant (S24A) abrogated the inhibitory function of DAB2. The spatial and temporal association/interaction of DAB2 and platelet integrin ␣ IIb ␤ 3 (CD61) in both megakaryocytic cells and platelets led us to examine the effect of Ser 24 phosphorylation on the interaction between DAB2 and integrin ␤ 3 . Through cellular localization and co-immunoprecipitation analysis, we demonstrate for the first time that Ser 24 phosphorylation promotes membrane translocation of DAB2 and its subsequent interaction with integrin ␤ 3 , thereby defining a mechanism for DAB2 in regulating integrin ␣ IIb ␤ 3 activation and inside-out signaling. Consistent with the effect on fibrinogen adhesion, Ser 24 phosphorylation of DAB2 was also involved in the negative regulation of ␣ IIb ␤ 3 -induced T cell factor transcriptional activity. In contrast, the S24A mutant acted like wild-type DAB2 and inhibited both ␤-catenin-and plakoglobin-mediated T cell factor transactivation. Hence, DAB2 elicits distinct regulatory mechanisms in ␣ IIb ␤ 3 and ␤-catenin/plakoglobin signaling in a Ser 24 phosphorylation-dependent and -independent manner, respectively. These findings indicate Ser 24 phosphorylation as a molecular basis for DAB2 acting as a negative regulator in ␣ IIb ␤ 3 inside-out signaling and contribute to our understanding of DAB2 in megakaryocytic differentiation and platelet function.Disabled-2 (DAB2) is an adapter protein that has been implicated in growth factor signaling (1, 2), endocytosis (3-5), cell adhesive function (6, 7), and hematopoietic cell differentiation (8). Like other adapter proteins, DAB2 elicits its function through interaction with other cellular proteins. DAB2 interacts with Grb2, myosin VI, SMAD2/3, DIP1/2, Dvl-3, the integrin ␤ subunit, and c-Src through the N-terminal phosphotyrosine-binding (PTB) 1 domain and the C-terminal proline-rich region (1, 4, 5, 9 -13). These interactions have been shown to modulate cytoskeleton organization, transcriptional activity, and cell signaling of various receptor protein-tyrosine kinases. DAB2 thus plays in a pivotal role in the control of cellular homeostasis.In cells, protein phosphorylation of DAB2 modulates its functional activity during growth factor signaling, megakaryocytic differentiation, macrophage spreading, and cell cycle progression. To date, protein kinase C (PKC) and...