Byung-Joo Kim

Menthol regulates TRPM8-independent processes in PC-3 prostate cancer cells

Menthol, a naturally occurring compound from peppermint oil, binds and activates the TRPM8 Ca(2+)-permeable channel that exhibits abnormal expression patterns in prostate cancer, suggesting that TRPM8 links Ca(2+) transport pathways to tumor biology. We thus investigated the cellular responses of prostate cancer cells to menthol. Here we found that menthol increases [Ca(2+)](i) via Ca(2+) influx mechanism(s) independent of TRPM8 in PC-3 cells. We demonstrated that menthol induces cell death at supramillimolar concentrations in PC-3 cells and the cell death is not suppressed by low extracellular Ca(2+) condition which indicates that menthol-induced cell death is not associated with Ca(2+) influx pathways. In addition, we showed that menthol increases a phosphorylated form of c-jun N-terminal kinase (JNK) in PC-3 cells through TRPM8-independent mechanisms. Thus, our data indicate that there is an apparent lack of causality between TRPM8 activation and menthol-induced cell death and that menthol can regulate TRPM8-independent Ca(2+)-transport and cellular processes.

1.04 GBd low EMI digital video interface system using small swing serial link technique

In a high-resolution flat panel system, a conventional interface that directly connects a liquid crystal display (LCD) controller to a flat panel cannot overcome the problems of excess EMI (electromagnetic interference) and power caused by full-swing transmission signals in parallel lines. This paper presents a high-speed digital video interface system implemented with a low-cost standard CMOS (complimentary metal-oxide-semiconductor) technology that can mitigate EMI and power problems in high-resolution flat panel display systems. The combined architecture of the high-speed, small number of parallel lines and low-voltage swing serial interface can support resolutions from VGA (640/spl times/480 pixels) up to XGA (1024/spl times/768 pixels) with significant power improvement and drastic EMI reduction. To support high-speed, low-voltage swing signaling and overcome channel-to-channel skew problems, a robust data recovery system is required. The proposed digital phase-locked loop enables robust skew-insensitive data recovery of up to 1.04 GBd.

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.

Charge ordering temperatures of Bi1-xSrxMnO3 (0.45 ≤ x ≤ 0.8)

We have investigated the charge ordering phenomenon from the temperature dependence of inverse susceptibility, resistivity, and thermoelectric power (TEP) for Bi1-xSrxMnO3 (BSMO) from 300 K to 700 K. At high temperatures, susceptibility follows Curie-Weiss law. The resistivity data indicate insulating behavior of BSMO. TEP (S(T)) value is negative and weakly temperature-dependent in the high temperature regime. The slope of TEP changes dramatically near the charge ordering temperature (ΤCO), indicating an increase of energy gap due to the charge ordering. In the vicinity of ΤCO, thermal hysteresis is observed in TEP data as well as in the resistivity data, which is consistent with the nature of the martensitic transition of the charge ordering phenomena. From this hysteretic behavior, we estimated ΤCO. As Sr concentration increases, ΤCO shifts to lower temperature from ΤCO ~ 490 K for x = 0.45 to ΤCO ~ 435 K for x = 0.8, and the thermal hysteretic behavior becomes less pronounced. The electrical transport properties have been discussed in terms of carrier localization due to charge ordering transition accompanied by the local lattice distortions.

A combined method for improving backpropagation algorithm

The authors present a new approach, called a combined method, for improving the backpropagation algorithm. They describe the standard backpropagation learning method and Newtons method. Experiments on three problems are reported: exclusive-OR, the encoder and the parity problem. The learning speeds are compared by epochs and CPU time. The performance of the combined method and Newtons method is compared. Experiments show that the combined method is faster than the standard backpropagation in epochs and more efficient than Newtons method in spaces and computations.<<ETX>>