Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors

Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0–3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC) in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g−1 was observed for the sample with a specific mass of 89 μg cm−2 at a scan rate of 2 mV s−1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES)

Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

Assessment of Air Pluviation Using Stationary and Movable Pluviators

Methods used for laboratory sample preparation should be able to produce uniform and highly repeatable sand beds of required density and to simulate field conditions. Air pluviation is a widely used method to prepare cohesionless soil samples in the laboratory. In the present study, two currently used air pluviation setups, viz, stationary/portable traveling pluviator (PTP) and movable/mechanized traveling pluviator (MTP), are investigated in terms of their ability to prepare uniform and repeatable sand beds of a wide range of relative densities. The PTP and MTP pluviation setups mainly comprise hopper, orifice, flexible hose, and rigid tube. Chain pulley and rail track are the additional features of MTP, which allow the hopper to travel smoothly in one direction. Pluviation studies are performed by using Indian standard sand (Grade II), and a California bearing ratio (CBR) mold is used to evaluate relative density (RD) and deposition intensity (DI) of samples. The effect of height of fall (HF), DI, and number of diffuser sieves on the RD of the sand sample is studied for both the PTP and MTP pluviation setups. A model tank is used to verify the uniformity of the sand samples with the help of miniature cone-penetrations tests. The test results reveal that a wide range of RD with uniform and repeatable sand samples can be prepared by using MTP compared with PTP. (C) 2016 American Society of Civil Engineers