Hepatic copper determination is an important test for the diagnosis of Wilson's disease (WD). However, the method has not been standardized, the diagnostic accuracy has not been evaluated prospectively, and the optimal cut‐off value remains controversial. Accordingly, we aimed to prospectively evaluate the diagnostic accuracy of hepatic copper content, as determined using the entire core of a liver biopsy sample. Patients for whom a liver biopsy was indicated were consecutively enrolled. Hepatic copper content was determined with atomic absorption spectroscopy. All assays were performed using careful quality control by a single technician. WD diagnosis was based on WD score or its combination with clinical follow‐up results. A total of 3,350 consecutive patients underwent liver biopsy. Six hundred ninety‐one patients, including 178 with WD, underwent two passes of liver biopsy with hepatic copper determination. Mean hepatic content in WD patients was 770.6 ± 393.2 μg/g dry weight (wt). Sensitivity, specificity, and positive and negative predictive values of hepatic copper content for WD diagnosis in the absence of primary biliary cirrhosis (PBC) or primary sclerosing cholangitis at the cut‐off value of 250 μg/g dry wt. were 94.4%, 96.8%, 91.8%, and 97.8%, respectively. The most useful cut‐off value was 209 μg/g dry wt, with a sensitivity and specificity of 99.4% and 96.1%, respectively. A total of 23.3% of patients without WD and PBC had hepatic copper content >75 μg/g dry wt. Conclusion: A liver biopsy sample of more than 1 mg dry wt may reliably reflect hepatic copper content and should be used for hepatic copper determination. Hepatic copper determination is a very valid procedure for the diagnosis of WD, and the most useful cut‐off value is 209 μg/g dry wt.(Hepatology 2015;62:1731–1741)
With the pervasiveness of mobile applications (apps), many Chinese libraries have begun to use apps to provide mobile services to users. Although many mobile library (m-library) apps have a high-downloaded rate in the App store, the rate of users continuing to use them remains extremely low, and the acceptance-discontinuance anomaly phenomenon (i.e., users discontinue using a m-library app after initially accepting it) is a common occurrence in China. This study develops an integrated model designed to explain and predict users’ continued usage of m-library apps based on the expectation confirmation model of information system continuance (ECM-ISC) and the theory of information system success, It incorporates habit, as a moderating variable of continuance intention and behaviour, into the model. Empirical data was collected from 396 users who had prior experience with m-library apps and was tested against the proposed research model using structural equation modelling. The results demonstrated that user perceived usefulness, expectation confirmation and satisfaction are important parts of the formation of m-library apps continuance usage. Furthermore, the three components of the information system success model, system quality, information quality and service quality, also have significant impacts on user confirmation and ultimately affect continuance usage. And the negative influence of habit on continuance intention and behaviour has been supported. The study will be useful for Chinese libraries to better understand users’ continuance usage behaviour and service demands, and in turn to optimize the function of apps and improve the quality of mobile services.
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