Differential role of hydrogen peroxide and organic peroxides in augmenting asbestos-mediated DNA damage: implications for asbestos induced carcinogenesis

The incubation of asbestos with DNA in presence of peroxides augmented DNA damage several fold as compared to the damage caused by individual treatments. Asbestos in presence of hydrogen peroxide causes DNA double strand breaks, damage to its deoxyribose sugar moiety and enhanced DNA fidelity. However, only DNA double strand breaks and enhanced DNA fidelity could be recorded in presence of organic hydroperoxide/peroxide but no DNA sugar damage could be observed. Further, the extent of DNA damage could be correlated to the carcinogenic potential of asbestos fibre. Crocidolite, the most carcinogenic variety of asbestos, produces maximum damage to DNA in presence of both hydrogen peroxide and organic hydroperoxide/peroxide while chrysolite which is only a co-carcinogen produces significantly less DNA damage. The observed differences in DNA damage by hydrogen peroxide and organic hydroperoxide/peroxide have been ascribed to the differential reactivity of DNA with hydroxyl and alkoxy/aryloxy free radicals produced respectively from these inorganic and organic peroxides.     

Examining Usability of Web Privacy Policies

Three studies examined (a) the amount and types of personal information requested by Web sites from seven different categories, (b) the goals and readability of existing privacy policies for four categories of sites, and (c) users' comprehension and perceptions of privacy policies. Study 1 showed that different amounts of personal information were requested by Web sites, even within the same category. Content and readability analyses of 100 privacy policies in Study 2 showed that policies tended to be high on both privacy protection and vulnerability goals or low on both. The policies were also written at a reading level corresponding to 13 years of education. Study 3 showed, though, that even college students have poor comprehension of the content of privacy policies. The students perceived longer policies that included many privacy goals as providing better assurance of privacy than shorter policies that included fewer goals. From a usability perspective, there is considerable room for improvement in the design of organizations' Web sites with respect to the amount and types of person information solicited and the implementation of privacy policies.     

Effect of pass deformation on microstructure, corrosion and electrochemical properties of aluminum alloy anodes for alkaline aluminum fuel cell applications

The effect of pass deformation in rolling processes on the microstructure, corrosion resistance and electrochemical activity of Al-Mg-Bi-Sn-Ga-In alloy anodes operated in an alkaline solution (85 °C, 5 mol·L^?1 NaOH with addition of NaSnO₃) with current density of 800 mA·cm^?2 was investigated. To analyze the microstructure of aluminum alloy anodes, we used scanning electron microscope, transmission electron microscope and electron backscatter diffraction techniques. We also used the hydrogen evolution method and electrochemical testing techniques to investigate the corrosion and electrochemical behavior of aluminum alloy anodes. The results showed that uniform microstructures with homogeneous distribution of fine active segregated phases as well as an excellent electrochemical performance of the aluminum alloy anodes were achieved by the dynamic recrystallization under pass deformation of 40%. We found that the aluminum alloy anodes (under pass deformation of 40%) had the lowest hydrogen evolution rate (0.092 mL·min^?1·cm^?2) and the most negative electrode potential (?1.585 V).     

Quantitation of Multiple Sphingolipid Classes Using Normal and Reversed-Phase LC–ESI–MS/MS: Comparative Profiling of Two Cell Lines

Sphingolipids are an important class of compounds that regulate signal transduction and other vital cellular processes. Herein, we report sensitive normal and reversed phase LC–MS/MS methods for quantitation of multiple sphingolipid classes. In the normal-phase ESI/MS/MS method, a high content of organic solvents was utilized, which, although it included hexane, ethyl acetate, acetonitrile containing 2% methanol, 1–2% acetic acid, and 5 mM ammonium acetate, resulted in a very efficient electrospray ionization of the ceramides (Cers) and hexosylceramides (MHCers). Three normal-phase LC–MS/MS methods using segmented phases were developed to specifically target Cers, MHCers, or sphingomyelins (SMs). This segmentation scheme increases the number of data points acquired for a given analyte and enhances the sensitivity and specificity of the measurements. Nine separate reversed phase chromatography methods were developed for the three classes of compounds. These assays were used for comparing the levels of Cers, SMs, and MHCers from mouse embryonic fibroblast (pMEF) and human embryonic kidney (HEK293) cells. These findings were then compared with the reported data from RAW264.7 mouse macrophage cells, BHK21 hamster cells, and human plasma and serum samples. The analysis of cell lines, using both normal and reversed phase chromatography, revealed discrimination based on the type of chromatography chosen, while sphingolipid assays of samples containing different amounts of protein showed different results, even after normalizing for protein content. Also, LC/MS/MS profiles were provided for the classes and individual compounds so that they could be used as “molecular profiles” for class or individual sample analysis.     

Nanocomposites: An Ideal Coating Material to Reduce the Sensitivity of Hydrazinium Nitroformate (HNF)

Hydrazinium nitroformate (HNF), an energetic and eco‐friendly oxidizer, was desensitized successfully by changing its crystal size and shape and by coating with a nanocomposite. During crystallization, various methods were tried out which include mechanical stirring, ultrasound and using crystal shape modifiers (CSMs). Experimental results showed that the multi‐pronged approach to control the shape and size of the crystals by a careful choice of CSMs and crystallization method worked well to counter the preferential axial crystals growth, thus shifting the long needles to near cubical shape. Among various coating agents, a hydroxy‐terminated poly butadiene (HTPB)‐based clay nanocomposite was found to be most effective for reducing the friction and impact sensitivity of HNF. A Scanning Electron Microscope (SEM) coupled with Energy Dispersive Spectroscopic (EDS) analysis was found to be a very reliable and most useful technique to assess the extent of coating on HNF so as to achieve a consistent figure of insensitivity. The coating material was stable as well as compatible with the HNF crystals as revealed by thermal analysis.     

Towards tunable polymer foam fabrication: A case study to advance green materials development in limited data scenarios

Early phases of green material development can be accelerated by identifying driving factors that control material properties to understand potential tradeoffs. Full investigation of fabrication variables is often prohibitively expensive. We propose a pared-down design of experiments (DOE) approach to identify driving variables in limited data scenarios using tunable polydimethylsiloxane (PDMS) foams made via sacrificial templating as an example system. This new approach systematically determines the dependencies of porosity, transparency, and fluid flow by varying the template particle size and packing while using a more sustainable solvent. Factor screening identified template particle size and packing density as the driving factors for foam performance by controlling pore size and interconnectivity. The framework developed provides a robust, foundational understanding of how to green and tune a novel material's properties using an efficient and effective exploration of the design space. Recommendations for applying this method to a broad suite of experiments are provided.