Matter-wave interference and deflection of tripeptides decorated with fluorinated alkyl chains

Studies of neutral biomolecules in the gas phase allow for the study of molecular properties in the absence of solvent and charge effects, thus complementing spectroscopic and analytical methods in solution or in ion traps. Some properties, such as the static electronic susceptibility, are best accessed in experiments that act on the motion of the neutral molecules in an electric field. Here, we screen seven peptides for their thermal stability and electron impact ionizability. We identify two tripeptides as sufficiently volatile and thermostable to be evaporated and interfered in the long‐baseline universal matter‐wave interferometer. Monitoring the deflection of the interferometric molecular nanopattern in a tailored external electric field allows us to measure the static molecular susceptibility of Ala–Trp–Ala and Ala–Ala–Trp bearing fluorinated alkyl chains at C‐ and N‐termini

The enlightenment and modern French studies

Inaugural lecture delivered at Rhodes UniversityRhodes University Libraries (Digitisation

Intuiting a Monsoonal Ethnography in Three Bay of Bengal Cities

This visual essay offers an exploration of monsoonal materiality and agency in the urban environments of three cities situated around the Bay of Bengal: Chennai, Dhaka and Yangon. The text and images emerge from a research project exploring intersections between changing monsoon climates and rapid urbanisation in South Asia. Multi-modal, more-than-human ethnography has been employed during the course of research to explore how the lively materiality of the monsoon is entangled within urban lived environments. The essay outlines the process of intuiting a monsoonal ethnography and conveys the power of immersive field experience. By collecting and curating an assemblage of visual material and fieldnotes, this piece seeks to evoke the materiality and agency of the monsoon, itself a complex assemblage that manifests in different ways in different places. The juxtaposition of image and text conveys the generative and multifaceted agency of the monsoon and the urban environments it becomes enmeshed within

Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses

This is the post-print version of the final paper published in Journal of Hazardous Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U–bacterial interaction experiments were performed at low pH values (2.0–4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase

The Professional Solution to the College Bubble

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