The diagnostic accuracy of urine-based tests for bladder cancer varies greatly by patient

BACKGROUND: Spectrum effects refer to the phenomenon that test performance varies across subgroups of a population. When spectrum effects occur during diagnostic testing for cancer, difficult patient misdiagnoses can occur. Our objective was to evaluate the effect of test indication, age, gender, race, and smoking status on the performance characteristics of two commonly used diagnostic tests for bladder cancer, urine cytology and fluorescence in situ hybridization (FISH). METHODS: We assessed all subjects who underwent cystoscopy, cytology, and FISH at our institution from 2003 to 2012. The standard diagnostic test performance metrics were calculated using marginal models to account for clustered/repeated measures within subjects. We calculated test performance for the overall cohort by test indication as well as by key patient variables: age, gender, race, and smoking status. RESULTS: A total of 4023 cystoscopy-cytology pairs and 1696 FISH-cystoscopy pairs were included in the analysis. In both FISH and cytology, increasing age, male gender, and history of smoking were associated with increased sensitivity and decreased specificity. FISH performance was most impacted by age, with an increase in sensitivity from 17 % at age 40 to 49 % at age 80. The same was true of cytology, with an increase in sensitivity from 50 % at age 40 to 67 % at age 80. Sensitivity of FISH was higher for a previous diagnosis of bladder cancer (46 %) than for hematuria (26 %). Test indication had no impact on the performance of cytology and race had no significant impact on the performance of either test. CONCLUSIONS: The diagnostic performance of urine cytology and FISH vary significantly according to the patient demographic in which they were tested. Hence, the reporting of spectrum effects in diagnostic tests should become part of standard practice. Patient-related factors must contextualize the clinicians’ interpretation of test results and their decision-making

Observed anomalous upwelling in the Lakshadweep Sea during the summer monsoon season of 2005

Repeat near-fortnightly expendable bathythermograph (XBT) transects made along Kochi-Kavaratti (KK) shipping lane in the Lakshadweep Sea (LS) during 2002–2006 are examined to describe the observed year-to-year variability of upwelling during summer monsoon season (SMS). Among all the years, the upwelling characterized by up-sloping of 25°C isotherm is relatively weaker and persisted until November during SMS of 2005 and is stronger during the SMS of 2002. As a result of prolonged upwelling, the sea surface temperature has shown cooling extending into the postmonsoon season. The estimated marine pelagic fish landings along the southwest coast of India (SWCI) have also shown increase until December. The governing mechanisms both in terms of local and remote forcings are examined to explain the observed anomalous upwelling during SMS of 2005. The equatorward alongshore wind stress (WS) along the KK XBT transect persisted in a transient manner beyond September only during SMS of 2005. The westerly wind bursts over the equator during the winter of 2004–2005 are both short-lived and relatively weaker triggering weaker upwelling Kelvin waves that propagated into LS in the following SMS of 2005. The observed distribution of negative sea surface height anomaly in the LS is relatively weaker during the SMS of 2005 and lasted longer. The correlation analysis suggests that the local alongshore WS off the SWCI and the remote forcing from the southern coast of Sri Lanka has greater influence on the observed interannual variability of upwelling in the LS when compared to the remote forcing from the equator

Integrated airline schedule optimization : models and solution methods

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996.Includes bibliographical references (p. 133-148).by Rajesh Gopalakrishna Shenoi.Ph.D

Electrochemically directed self-assembly and conjugated polymer semiconductors for organic electronic applications

The research work presented in this thesis investigates the mechanistic details of conventional as well as electrochemically directed self-assembly of alkylthiosulfates and explores the use of conjugated semiconducting polymers for organic electronic applications. Here, the significance of the use of conjugated polymers is twofold; first, to explore their applications in nanoelectronics and second, the possibility of using them as a top contact on the self-assembled monolayers (SAMs) for molecular electronic applications. Throughout this work, deposition of the organic materials was performed on prefabricated device structures that required no further lithographic or metal deposition steps after modification of the electrodes with the organic molecules. Self-assembly of alkylthiosulfates on gold are reported to form monolayers identical to those formed from the corresponding alkanethiols. However, these self-assembly processes follow more complex mechanisms of monolayer formation than originally recognized. Studies on the mechanism of alkylthiosulfate chemisorption on gold shows that the self-assembly process is influenced by electrolyte and solvent. Plausible mechanisms have been proposed for the role of trace water in the solvent on conventional as well as electrochemically assisted self-assembly of alkylthiosulfates on gold. Electroanalytical and spectroscopic techniques have been used to explore the mechanistic details of electrochemically directed self-assembly of alkylthiosulfates on gold. It has been found that the self-assembly process is dynamic under electrochemical conditions and the heterogeneous electron transfer process between the organosulfur compound and gold is mediated through gold surface oxide and accompanied by corrosion. Conducting polymers are serious candidates for organic electronic applications since their properties can be controlled by the manipulation of molecular architecture. Unique electronic properties of conjugated polypyrrole hybrid materials (PPy0DBS-Li+) with immobile dopant anions and mobile cations have been observed and explained on the basis of movement of the cations in an applied electric field. Based on this principle, functioning polymer resistive memory devices have been demonstrated which can be scalable to lower dimensions for nanoelectronics applications. Finally, proof of concept for using a conducting polymer as a top contact in molecular electronic devices created using electrochemically directed self-assembly is demonstrated.February 201