Measurement of the Forward-Backward Charge Asymmetry in Top-Quark Pair Production in Proton-Antiproton Collisions at D0

A measurement of the forward-backward charge asymmetry in top-antitop (t\bar{t}) pair production in proton-antiproton (p\bar{p}) collisions is presented. The asymmetry is measured for different jet multiplicities in the lepton+jets final state on 0.9 fb^{-1} of data collected by the D0 experiment at the Fermilab Tevatron Collider. The result is sensitive to new physics, which is demonstrated by setting an upper limit on t\bar{t} production via heavy neutral gauge bosons (Z^{\prime}).Comment: Presented at 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY08), Seoul, Korea, 16-21 Jun 200

Clean relaying aided cognitive radio under the coexistence constraint

We consider the interference-mitigation based cognitive radio where the primary and secondary users can coexist at the same time and frequency bands, under the constraint that the rate of the primary user (PU) must remain the same with a single-user decoder. To meet such a coexistence constraint, the relaying from the secondary user (SU) can help the PU's transmission under the interference from the SU. However, the relayed signal in the known dirty paper coding (DPC) based scheme is interfered by the SU's signal, and is not "clean". In this paper, under the half-duplex constraints, we propose two new transmission schemes aided by the clean relaying from the SU's transmitter and receiver without interference from the SU. We name them as the clean transmitter relaying (CT) and clean transmitter-receiver relaying (CTR) aided cognitive radio, respectively. The rate and multiplexing gain performances of CT and CTR in fading channels with various availabilities of the channel state information at the transmitters (CSIT) are studied. Our CT generalizes the celebrated DPC based scheme proposed previously. With full CSIT, the multiplexing gain of the CTR is proved to be better (or no less) than that of the previous DPC based schemes. This is because the silent period for decoding the PU's messages for the DPC may not be necessary in the CTR. With only the statistics of CSIT, we further prove that the CTR outperforms the rate performance of the previous scheme in fast Rayleigh fading channels. The numerical examples also show that in a large class of channels, the proposed CT and CTR provide significant rate gains over the previous scheme with small complexity penalties.Comment: 30 page

Coexistence of anterior communicating artery aneurysm and tuberculum sellae meningioma

SummaryTuberculum sellae meningioma is a common intracranial tumor. However, its coexistence with an intratumoral aneurysm is rare. Here, we present the case of a 65-year-old woman with progressive vision loss caused by a tuberculum sellae meningioma coexisting with an intratumoral anterior communicating artery aneurysm. Treatment modalities for patients with this rare coexisting pathology were reviewed. When an intracranial tumor is closely related to the major intracranial vessel, preoperative magnetic resonance imaging angiography, a safe and noninvasive imaging study, is suggested for the early diagnosis of a possible coexisting aneurysm and for reducing the risk of intraoperative aneurysm rupture

Silicon germanium photo-blocking layers for a-IGZO based industrial display

Amorphous indium- gallium-zinc oxide (a-IGZO) has been intensively studied for the application to active matrix flat-panel display because of its superior electrical and optical properties. However, the characteristics of a-IGZO were found to be very sensitive to external circumstance such as light illumination, which dramatically degrades the device performance and stability practically required for display applications. Here, we suggest the use for silicon-germanium (Si-Ge) films grown plasmaenhanced chemical vapour deposition (PECVD) as photo-blocking layers in the a-IGZO thin film transistors (TFTs). The charge mobility and threshold voltage (V-th) of the TFTs depend on the thickness of the Si-Ge films and dielectric buffer layers (SiNX), which were carefully optimized to be similar to 200 nm and similar to 300 nm, respectively. As a result, even after 1,000 s illumination time, the V-th and electron mobility of the TFTs remain unchanged, which was enabled by the photo-blocking effect of the Si-Ge layers for a-IGZO films. Considering the simple fabrication process by PECVD with outstanding scalability, we expect that this method can be widely applied to TFT devices that are sensitive to light illumination.

Menthol Enhances an Antiproliferative Activity of 1α,25-Dihydroxyvitamin D3 in LNCaP Cells

1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], the most active form of vitamin D3, and its analogues have therapeutic benefits for prostate cancer treatment. However, the development of hypercalcemia is an obstacle to clinical applications of 1α,25(OH)2D3 for cancer therapy. In this study, we provide evidence that menthol, a key component of peppermint oil, increases an anti-proliferation activity of 1α,25(OH)2D3 in LNCaP prostate cancer cells. We found that menthol per se does not exhibit antiproliferative activity, but it is able to enhance 1α,25(OH)2D3-mediated growth inhibition in LNCaP cells. Fluorometric assays using Fura-2 showed that 1α,25(OH)2D3 does not induce acute Ca2+ response, whereas menthol evokes an increase in [Ca2+]i, which suggests that cross-talks of menthol-induced Ca2+ signaling with 1α,25(OH)2D3-mediated growth inhibition pathways. In addition, Western blot analysis revealed that 1α,25(OH)2D3 and menthol cooperatively modulate the expression of bcl-2 and p21 which provides the insight into the molecular mechanisms underlying the enhanced 1α,25(OH)2D3-mediated growth inhibition by menthol. Thus, our findings suggest that menthol may be a useful natural compound to enhance therapeutic effects of 1α,25(OH)2D3