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Accurate positioning in global navigation satellite system (GNSS)-denied environments, such as tunnels and underpasses, remains a challenge. Navigation systems for such environments need to strike a balance between price and precision. In this paper, we propose magnetic vehicular positioning (MVP), a navigation system that guides drivers in GNSS-denied environments. The key idea of MVP is to extract magnetic fingerprints from geomagnetic field anomalies. By comparing the measured magnetic field against a magnetic map, positioning can be achieved without GNSS signals. Our proposed matching algorithm allows MVP to provide 5.14 m positioning accuracy. We conducted large-scale real-road experiments for 36 months in two countries and 56 tunnels to demonstrate the effectiveness of the proposed system. Because MVP can be deployed on off-the-shelf smartphones, our approach makes accurate navigation in GNSS-denied environments affordable.

Aim: To investigate the transforming growth factor β1 (TGF-β1) and basic fibroblast growth factor (bFGF) expressions in benign prostatic hyperplasia (BPH) and the effect of β-radiation. Methods: TGF-β1 and bFGF expression was studied by means of an immunohistochemical method in nine normal prostatic (NP) tissues, 15 hyperplastic prostatic tissues and 35 hyperplastic prostatic tissues treated with 90 Sr/ 90 Y. Results: The TGF-β1 expression in the epithelium and stroma of normal prostatic tissues was 68.2 % ± 10.5 % and 29.7 % ± 4.6 %, respectively, while it was 64.8 % ± 9.3 % and 28.6 % ± 4.1 %, respectively, in hyperplastic prostatic tissues. Compared with the controls, TGF-β1 expression in the epithelia and stroma of BPH treated with 90 Sr/ 90 Y increased significantly (P < 0.01). The bFGF expression in epithelia and stroma of normal prostatic tissues was 17.4 % ± 3.7 % and 42.5 % ± 6.8 %, respectively, and was 46.3 % ± 8.2 % and 73.2 % ± 12.1 %, respectivley, in hyperplastic prostatic tissues. Compared with the controls, expressions of bFGF in the epithelia and stroma of BPH treated with a 90 Sr/ 90 Y prostatic hyperplasia applicator decreased significantly (P < 0.01). Conclusion: Exposure of β-rays had noticeable effects on BPH tissues, enhancing TGF-β1 expression and inhibiting bFGF expression. (Asian J Androl 2005 Mar; 7: 49–54)