Designing a Programming Contract Library for Java

Programmers are now developing large and complex software systems, so it’s important to have software that is consistent, efficient, and robust. Programming contracts allow developers to specify preconditions, postconditions, and invariants in order to more easily identify programming errors. The design by contract principle [1] was first used in the Eiffel programming language [2], and has since been extended to libraries in many other languages. The purpose of my project is to design a programming contract library for Java. The library supports a set of preconditions, postconditions, and invariants that are specified in Java annotations. It incorporates contract checking for objects of classes following the bean notation [3]. The library also supports checking for user-defined functions as contract conditions. This feature allows the user to check for complex contract conditions. In addition to these, the library supports contracts using lambdas in Java 8 [4], which to our knowledge has not been done in previous works on Java contracts. While the results show us that enabling contracts lowers the performance of the system, especially when lambda contracts are used, we also demonstrate how careful design can significantly reduce the overhead

Establishment of a predictive model for early virologic response in previously untreated chronic hepatitis B patients treated with telbivudine

Objective To investigate the establishment of a predictive model for early virologic response in previously untreated chronic hepatitis B (CHB) patients treated with telbivudine, since early virologic response can predict the long-term efficacy of nucleotide analogues. MethodsA total of 135 CHB patients who visited Mengchao Hepatobiliary Hospital of Fujian Medical University from January 2007 to August 2014 were enrolled and treated with telbivudine (600 mg qd) for at least 24 weeks. Follow-up was performed once every 2 weeks, and the patients′ baseline data and data measured during treatment were recorded. The t-test was used for comparison of continuous data between groups, the chi-square test was used for comparison of categorical data between groups, and the Cox proportional hazards regression model was used to analyze the influencing factors for early virologic response and establish the predictive model. ResultsThe patients without a family history of hepatitis B virus (HBV) infection (P=0.000 3) and with high baseline levels of total bilirubin (TBil) (P=0.002 6) and aspartate aminotransferase (AST) (P=0.007 4) and a low HBV DNA load (P=0.002 3) tended to show early virologic response. The predictive model was established based on these variables, and the risk score (R) of CHB patients was calculated. The CHB patients with R＞0.85 were more likely to achieve early virologic response. ConclusionThe model established based on the four variables of family history, baseline TBil level, baseline AST level, and HBV DNA level can well predict early virologic response in previously untreated CHB patients treated with telbivudine

Increased Serum Soluble Urokinase Plasminogen Activator Receptor Predicts Short-Term Outcome in Patients with Hepatitis B-Related Acute-on-Chronic Liver Failure

Aims. Soluble urokinase plasminogen activator receptor (suPAR) reflects the immune activation in circumstances of inflammation and infection. It has been considered as a risk biomarker associated with poor outcome in various low-grade inflammation and infectious diseases. The study is aimed at investigating whether suPAR has a predictive value with short-term survival in patients with hepatitis B-related acute-on-chronic liver failure (HB-ACLF). Methods. Serum suPAR expression was compared among patients with different states of chronic hepatitis B virus infection. Sixty HB-ACLF patients were recruited as the training cohort and followed up for 90 days. Serum suPAR level and the clinical relevance with short-term outcome were investigated. The temporal dynamics of suPAR were evaluated in 50 HB-ACLF patients with available serum sequentially at baseline, week 2 and week 4. Another 167 HB-ACLF patients were enrolled to validate the predictive value of suPAR with respect to the prognosis. Results. Serum suPAR level was significantly increased in HB-ACLF patients compared to non-ACLF patients. In the training set of HB-ACLF, we observed higher suPAR level, INR, MELD score, and more complications in nonsurvivors than survivors. Longitudinal analysis revealed an increased trend of suPAR level in nonsurvivors during week 0 to week 4 and the modest decline in survivors. It showed that the synchronous suPAR level was higher in nonsurvivors at all indicated time points. Elevated suPAR level at baseline was identified as a strong predictor of a 90-day mortality of HB-ACLF patients. It was confirmed suPAR>16.26 ng/ml had a positive predictive value of 72.22% and a negative predictive value of 77.88% for poor outcome in the validation cohort. Conclusions. Serum suPAR level increases significantly in HB-ACLF patients and associated with a 90-day mortality. It suggests that suPAR might be a potential biomarker to predict the prognosis of HB-ACLF patients