Discrimination of bacteria by rapid sensing their metabolic volatiles using an aspiration-type ion mobility spectrometer (a-IMS) and gas chromatography-mass


The objective of our study was to investigate whether one may quickly and reliably discriminate different microorganism strains by direct monitoring of the headspace atmosphere above their cultures. Headspace samples above a series of in vitro bacterial cultures were directly interrogated using an aspiration type ion mobility spectrometer (a-IMS), which produced distinct profiles (“fingerprints”) of ion currents generated simultaneously by the detectors present inside the ion mobility cell. Data processing and analysis using principal component analysis showed net differences in the responses produced by volatiles emitted by various bacterial strains. Fingerprint assignments were conferred on the basis of product ion mobilities; ions of differing size and mass were deflected in a different degree upon their introduction of a transverse electric field, impacting finally on a series of capacitors (denominated as detectors, or channels) placed in a manner analogous to sensor arrays.

A method for anomaly detection in hyperspectral images, using deep convolutional autoencoders

Detecting anomalies from any image data, especially hyperspectral ones, is not a trivial task. When combined with the lack of apriori labels or detection targets, it grows even more complex. Detecting spectral anomalies can be done with numerous methods, but the detection of spatial ones is vastly more complicated affair. In this thesis a new way to detect both spatial and spectral anomalies at the same time is proposed.

Inter-laboratory exercise with an aim to compare methods for 90Sr and 239,240Pu determination in environmental soil samples

In order to deliver reliable results for a multitude of different scenarios, e.g. emergency preparedness, environmental monitoring, nuclear decommissioning and waste management, there is a constant process of method development in the field of radioanalytical chemistry. This work presents the results of a method comparison exercise aimed at quantifying 90Sr and 239,240Pu in environmental soil samples, with the intention of evaluating the performance and applicability of different methods. From the methods examined in this work, recommendations are given in order to find a radioanalytical measurement procedure, for 90Sr and 239,240Pu analysis, which is fit-forpurpose for a particular scenario.

A rapid and non-invasive method to determine toxic levels of alcohols and γ-hydroxybutyric acid in saliva samples by gas chromatography-differential mobility spectrometry

Work over the first eighteen months of the project has identified metabolomic markers of exposure to pesticides and toxic alcohols. A publication by Prof Thomas's Loughborough group reported identification of the toxic alcohols methanol, ethylene glycol, and 1,3-propandiol, and their metabolites, as well as ethanol in human saliva.

Biological toxins of potential bioterrorism risk: Current status of detection and identification technology

Biological toxins are a heterogeneous group of compounds that share commonalities both with biological and chemical agents. Based on their availability, toxicity, and the lack of medical countermeasures as well as their known history of military research, toxins such as ricin, botulinum neurotoxins, staphylococcal enterotoxins, and saxitoxin are classified as toxins of bioterrorism risk.

Volatile organic compound markers of psychological stress in skin: a pilot study

The forehead was studied as a possible sampling site for capturing changes in volatile organic compound (VOC) profiles associated with psychological-stress. Skin-VOCs were sampled with a polydimethylsilicone (PDMS)-coupon and the resulting VOCs were recovered and analysed with two-stage thermal desorption gas chromatography-mass spectrometry.

Mental health surveillance after the terrorist attacks in Paris

The terror events in Paris in November, 2015, and elsewhere remind us of the substantial consequences that violent events can have for a population's mental health. Although effective approaches exist for treating these consequences, no systematic attempts have been made to identify populations at risk early on to expeditiously mitigate them. Social media could help identify populations in need during and after disasters.