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The relationship between the structure characteristics and performances of coal-based hydrogenation isomeric (CTL) base oil and metallocene-catalyzed coal-based poly-alpha-olefin (mPAO) base oil is clarified in this paper. CTL and mPAO were compared with typical petroleum-based and natural gas-based commercial API III and IV base oils. Pressurized differential scanning calorimetry (PDSC), the rotary bomb oxidation test (RBOT), and a four-ball friction tester were used to evaluate the oxidation stability and lubrication performance of base oils under different working conditions. The sensitivity of different base oils to typical antioxidants and extreme-pressure antiwear agents was compared. In particular, the composition and structure of CTL base oil are clearly different from GTL and mineral base oil. The coal-based CTL and mPAO base oils exhibit commendable viscosity–temperature properties, coupled with low-temperature fluidity, fire safety, and minimal evaporation loss. The lubricating properties, oxidation stability, and sensitivity to extreme-pressure antiwear agents of CTL are close to those of similar base oils. However, the sensitivity of CTL to typical antioxidants is relatively poor. In addition, compared with commercial PAO base oil, mPAO has a lower isomerization degree and fewer isomerization types. The oxidation stability and sensitivity to typical antioxidants of mPAO base oil are comparable with those of commercial PAO base oil, while its lubrication performance and sensitivity to typical extreme-pressure antiwear agents are significantly better than those of commercial PAO base oil. [ABSTRACT FROM AUTHOR]

The relationship between the structure characteristics and performances of coal-based hydrogenation isomeric (CTL) base oil and metallocene-catalyzed coal-based poly-alpha-olefin (mPAO) base oil is clarified in this paper. CTL and mPAO were compared with typical petroleum-based and natural gas-based commercial API III and IV base oils. Pressurized differential scanning calorimetry (PDSC), the rotary bomb oxidation test (RBOT), and a four-ball friction tester were used to evaluate the oxidation stability and lubrication performance of base oils under different working conditions. The sensitivity of different base oils to typical antioxidants and extreme-pressure antiwear agents was compared. In particular, the composition and structure of CTL base oil are clearly different from GTL and mineral base oil. The coal-based CTL and mPAO base oils exhibit commendable viscosity–temperature properties, coupled with low-temperature fluidity, fire safety, and minimal evaporation loss. The lubricating properties, oxidation stability, and sensitivity to extreme-pressure antiwear agents of CTL are close to those of similar base oils. However, the sensitivity of CTL to typical antioxidants is relatively poor. In addition, compared with commercial PAO base oil, mPAO has a lower isomerization degree and fewer isomerization types. The oxidation stability and sensitivity to typical antioxidants of mPAO base oil are comparable with those of commercial PAO base oil, while its lubrication performance and sensitivity to typical extreme-pressure antiwear agents are significantly better than those of commercial PAO base oil.

BACKGROUND At a high-volume center, it became necessary to provide benchmarks for the accuracy and risk of malignancy per urine cytology diagnostic category. The additive sensitivity for the determination of the residual risk of disease was calculated with the goal of determining the performance of cytology and optimal triage, including the number of urine samples, before the detection of malignancy in surveillance patients. METHODS A 2-year laboratory information system-based search was conducted, and it yielded 587 subjects (695 biopsy and cytology pairs) with histological follow-up. The sensitivity and specificity of cytology for urothelial malignancy, the risk of malignancy per diagnostic category, the additive sensitivity, and the time for conversion from a negative initial cytology result to a positive cytology result were examined. RESULTS The overall average sensitivity and specificity of cytology were 48.9% and 83.0%, respectively. The additive sensitivity increased with each subsequent cytology and peaked with the third cytology. A median conversion time of 22.2 months from a negative initial cytology result to a positive cytology result and a decline in predictive positive cytology after the fourth cytology were noted. Subcategorization of the atypical category failed to show statistical significance in predicting outcomes of biopsy. Surveillance subjects, as compared to primary subjects, showed a higher sensitivity for the detection of high and low grade cancers. CONCLUSIONS The findings suggest that atypia favoring malignancy is being appropriately flagged. However, further definition of the atypical category is needed to increase specificity with a better qualitative or quantitative morphological algorithm. This study provides a risk of malignancy for each category for benchmarking and clinical triage. The data suggest that follow-up should include at least 4 consecutive urine specimens over a period of 22.2 months. Cancer (Cancer Cytopathol) 2015;123:10-8. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]