Application of a Fluid-Structure Interaction Model for Analysis of the Thermodynamic Process and Performance of Boil-Off Gas Compressors.

Boil-off gas (BOG) compressors are among the most critical devices in transportation and receiving systems for liquid natural gas (LNG) because they are used to pump out excess BOG from LNG storage tanks to ensure safety. Because of the ultralow suction temperature, the influence of heat transfer between the cold gas and the compressor parts on the in-cylinder thermodynamic process cannot be ignored. This paper reports the effects of suction temperature on the thermodynamic process and performance of a BOG compressor with consideration of gas pulsation. A computational fluid dynamics (CFD) model with dynamic and sliding meshes was established, in which user-defined functions (UDFs) were used to calculate the real-time valve lift to realize coupling between the thermodynamic process and the gas pulsation, and a performance test rig was constructed to verify the proposed numerical model. The simulated results agreed well with the experimental ones. The results show that as the suction temperature decreased from 30 °C to -150 °C, the first-stage volumetric efficiency decreased to 0.69, and the preheating increased to 45.8 °C. These results should provide academic guidance and an experimental basis for the design and optimization of BOG compressors.

[Human papillomavirus infection in oropharyngeal squamous cell carcinoma and prognosis: a preliminary analysis of 66 cases].

OBJECTIVE: To analyze the relationship between the prognosis of patients with oropharyngeal squamous cell carcinoma (OSCC) and human papillomavirus (HPV) infection in OSCC. METHODS: Sixty-six patients with oropharyngeal carcinoma who met the enrollment criteria during the period from January 1999 to December 2009 were retrospectively reviewed. The presence or absence of HPV oncogenic types in OSCC specimen was determined by multiplex polymerase chain reaction (PCR). Overall survival (OS) and disease specific survival (DSS) for HPV-positive and HPV-negative patients were estimated by Kaplan-Meier analysis. Cox regression model was used for multivariate analysis. RESULTS: HPV-DNA was detected in 11(16.7%) of all specimens. Among them, 7 were positive for HPV-16, 1 for HPV-16/11, 1 for HPV-35, 1 for HPV-58/52, and 1 for HPV-33/52/54. With the follow-up of 3-78 months (a median of 24.5 months), patients with HPV-positive tumors had significantly better overall survival (χ2=5.792, P=0.016) and disease specific survival (χ2=4.721, P=0.030), the 3-year OS and DSS were 90.0% vs 52.4% and 90.0% vs 56.4%, respectively. Multivariate analysis by Cox regression model showed that HPV infection and nodal status were both independent prognostic factors for patients with OSCC (P<0.05). CONCLUSIONS: Patients with HPV-positive OSCC have significantly better prognosis than patients with HPV-negative tumors. HPV infection is an independent prognostic factor.

Human papillomavirus infection and prognostic predictors in patients with oropharyngeal squamous cell carcinoma.

This study focused on infection rates and subtypes of human papillomavirus (HPV) in patients with oropharyngeal squamous cell carcinoma (OSCC), and the relationship between HPV status and prognosis of the disease. We evaluated sixty-six OSCC patients who met the enrollment criteria during the period from January 1999 to December 2009. The presence or absence of oncogenic HPV types in tumors was determined using the SPF10 LiPA25 assay. Overall survival (OS) and disease specific survival (DSS) for HPV positive and HPV negative patients were estimated using Kaplan-Meier analysis. The Cox regression model was applied for multivariate analysis. HPV-DNA was detected in 11(16.7%) of all specimens. Among them, 7 were type HPV-16, while other types were HPV-16/11, HPV-35, HPV-58/52, and HPV-33/52/54. Patients with HPV positive tumors were more likely to be female, non-smokers and non-drinkers (p=0.002, 0.001 and 0.001, respectively). After a median follow-up of 24.5 months, patients with HPV positive tumors had significantly better overall survival (HR=0.106[95%CI=0.014-0.787], p=0.016,) and disease specific survival (HR=0.121[95%CI=0.016-0.906], p=0.030). Patients with HPV positive OSCC have significantly better prognosis than patients with HPV negative tumors. HPV infection is an independent prognostic factor.