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A wind and structural health monitoring system (WASHMS) was installed in the Tsing Ma suspension bridge in Hong Kong in 1997. On September 16, 1999, Typhoon York, which was the strongest typhoon since 1983 and the typhoon of the longest duration on record, crossed over Hong Kong. All vehicles, except trains, were prohibited from running on the bridge for 2.5 h. This event provided a distinctive opportunity to examine the existing analytical models for predicting dynamic response of long suspension bridges to high winds and running trains. The field measurement data recorded by the WASHMS during this event were therefore analyzed and the four particular cases were identified and discussed in this paper. The four particular cases identified included: (1) the bridge without any vehicles; (2) the bridge with one train; (3) the bridge with two trains running in opposite directions; and (4) the bridge with three running trains. The mean wind speed was almost perpendicular to the bridge alignment in the four cases to facilitate the comparison with analytical results. For each case, wind characteristics, bridge acceleration responses, and bridge displacement responses were analyzed using the measurement data from anemometers, accelerometers, and level sensing systems, respectively. The number of trains running on the bridge, train speed, and train location were also identified using the measurement data from strain gauges. The measurement results clearly demonstrated the dynamic behavior of the bridge with running trains during high winds. The measurement results obtained will also be used to verify the analytical model developed by the authors in the companion paper. [ABSTRACT FROM AUTHOR]

The field measurement results of the Tsing Ma suspension bridge under cross winds and running trains during Typhoon York have been presented in Part I of this study. The field measurement results are used in this paper (Paper II) to verify, to some extent, the finite element based framework developed by the writers in the time domain for predicting dynamic response of coupled train and bridge systems in cross winds. In this regard, a three-dimensional finite element model is used to model the Tsing Ma suspension bridge. Wind forces acting on the bridge are generated in the time domain using a fast spectral representation method and based on the field measurement results and wind tunnel test results. Each coach in a train running on the bridge is modeled by a 27 degree-of-freedom dynamic system. The dynamic interaction between the bridge and the train is realized through the contact forces between the wheels and the track. Track irregularity is simulated using a high-order multivariate autoregressive model, whereas wheel hunting is assumed to be a sinusoidal function with a random phase. The acceleration and displacement responses of the bridge under cross winds and running trains are computed and compared with the responses measured from the field for four cases. The comparison is found to be satisfactory in general. The dynamic response and performance of trains on the bridge is also computed and evaluated. The proposed framework is found to be feasible and practical. [ABSTRACT FROM AUTHOR]

Peptic ulcer disease is mainly caused by Helicobacter pylori infection and the use of non-steroidal anti-inflammatory drugs. To investigate the trends in the prevalence of peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use in uninvestigated dyspeptic patients over recent years in Hong Kong. Data from consecutive patients with uninvestigated dyspeptic symptoms referred by family physicians for open access upper endoscopy during 1997 and 2003 were analysed in relation to peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use. Among 2700 patients included, 405 (15%) had peptic ulcer disease and 14 (0.5%) had gastric cancer. There was a reduced trend from 1997 to 2003 in the prevalence of peptic ulcer disease (17, 20, 14, 16, 13, 14 and 14%, respectively, χ2 = 5.80, P = 0.016) (mainly because of decrease in duodenal ulcers), H. pylori infection (44, 50, 49, 44, 40, 40, 36 and 43%, respectively, χ2 = 13.55, P < 0.001) and non-steroidal anti-inflammatory drug use (13, 5, 5, 6, 3, 4, 4 and 5% respectively, χ2 = 13.61, P < 0.001). The prevalence of peptic ulcer disease, H. pylori infection and non-steroidal anti-inflammatory drug use between 2001 and 2003 were significantly lower than that between 1997 and 2000 (17% vs. 13%, OR = 0.78, 95% CI: 0.63–0.96, P = 0.020 for peptic ulcer disease; 47% vs. 39%, OR =0.72, 95% CI: 0.60–0.86, P < 0.001 for H. pylori infection; and 6% vs. 4%, OR = 0.56, 95% CI: 0.39–0.82, P = 0.002 for non-steroidal anti-inflammatory drug use). H. pylori infection was associated with both duodenal ulcer (OR = 15.87, 95% CI: 10.60–23.76, P < 0.001) and gastric ulcer (OR = 3.12, 95% CI: 2.15–4.53, P < 0.001) whereas non-steroidal anti-inflammatory drug use was only associated with gastric ulcer (OR = 2.97, 95% CI: 1.70–5.20, P < 0.001). The prevalence of peptic ulcer disease, mainly duodenal ulcers, was reduced in association with a decreasing trend in the prevalence of H. pylori infection and non-steroidal anti-inflammatory drug use from 1997 to 2003. [ABSTRACT FROM AUTHOR]

: The performance of commercialHelicobacter pyloridiagnostic kits developed for particular geographic regions has often been found to be of poor diagnostic value when applied to other regions, possibly because of infections being caused by differentH. pyloristrains in different regions.: To evaluate the performance of an IgG2 anti-H. pylorienzyme-linked immunoassay test (Helirad Alert) for detection ofH. pyloriinfection in both Australian and Hong Kong (Chinese) subjects.: Serum samples were tested forH. pylorispecific IgG2 and IgG antibodies by enzyme-linked immunoassay kits using identical antigen preparation in 168 Australian and 160 Hong Kong (Chinese) subjects diagnosed with dyspepsia.: Using a cut-off value determined by analysis ofH. pylori-negative Australian samples, the sensitivity, specificity and accuracy of the IgG2 assay were 77.8, 97.4 and 91.1%, respectively, for the Australian samples and 96.3, 83.8 and 90% for Hong Kong samples. For the IgG assay, sensitivity, specificity and accuracy were 87.0, 99.1 and 95.2% for Australian samples and 97.5, 75 and 86.3% for Hong Kong samples respectively. Receiver-operating characteristic analysis showed better discrimination ofH. pyloristatus when the IgG2 assay was applied to Hong Kong samples, while the IgG assay was better in the Australian samples.: These data demonstrate that the Helirad Alert enzyme-linked immunoassay could provide a reliable method for screeningH. pyloriinfection in both western and Chinese populations. [ABSTRACT FROM AUTHOR]