Control of Uplift from Ground Water

This paper relates to the conversion of a disused water reservoir into a landfill site for domestic and industrial refuse. The reservoir was initially subdivided into four cells (by using earth bunds) and three of the cells have been successfully prepared and filled. The fourth cell is the largest and presents the greatest number of geotechnical problems, the major one being the problem of ensuring that leachate does not escape into the groundwater. The first owner of the site removed natural clay from various parts of the reservoir base to seal the first three cells. In doing so he exposed water-bearing sandstones, mudstones and badly-shattered shales and ground water is now issuing freely from these strata. Standpipes in the base of the completed cells indicate a significant artesian pressure in the groundwater and sealing of the exposed rocks in cell 4 represents a major problem. In an attempt to form a low permeability seal with compacted clay temporary pressure relief drains have been installed to connect with the water bearing rocks. However closure of these drains may lead to excessive uplift pressure and rupture of the seal and so the relief drains will be left open, whilst waste is placed, until they can be safely closed

Liquid micro-junction surface sampling and MALDI imaging of small and large molecules in human liver disease

In this thesis, Liquid extraction surface analysis (LESA) mass spectrometry has been applied for the analysis of lipids and proteins from human liver. The aim was to develop analytical methods that would ultimately be used in the study of non-alcoholic liver disease. Top-down proteomic analysis of the fatty acid binding protein identified a single amino acid substitution that is associated with non-alcoholic steatohepatitis, a potentially fatal liver disease. Bottom-up proteomics techniques resulted in over 300 proteins being detected and identified, however failed to distinguish between a single amino acid substitution. Field asymmetric ion mobility spectrometry (FAIMS) analysis was coupled with LESA to enhance the quality of intact protein mass spectra and doubled the number of proteins detected. FAIMS analysis was able to separated lipids and proteins that were extracted simultaneously as well as removing background noise. In addition to FAIMS, traveling wave ion mobility spectrometry (TWIMS) was also coupled to LESA. In addition to the separation of lipids from proteins, several lipids also showed a separation in drift. MS/MS of one of these lipids revealed that the composition of the two drift peaks differed. MALDI imaging was performed to show the isolation of specific lipid species using MS/MS and TWIMS

Nanoelectronic and nanomechanical devices for low temperature applications

Cooling physical experiments to low temperatures removes thermal excitations to reveal quantum mechanical phenomena. The progression of nanotechnologies provides new and exciting research opportunities to probe nature at ever smaller length scales. The coupling of nanotechnologies and low temperature techniques has potential for scientific discoveries as well as real world applications. This work demonstrates techniques to further extend physical experimental research into the millikelvin-nanoscale domain. The challenge of thermometry becomes an increasingly complex problem as the temperature of a physical system lowers. We describe the development and methods for a specially modified Coulomb blockade thermometer to achieve electron thermometry below 4mK overcoming the challenge of electron thermalisation for on-chip devices. Mechanically vibrating devices can directly probe bulk and surface fluid properties. We developed practical measurement techniques and analysis methods to demonstrate the use of nanomechanical resonators, which for the first time were used to probe both the normal and the superfluid phases of helium-4. The doubly clamped beams had a cross section of 100nm by 100nm and were tested in length variants between 15um to 50um, The flexural resonance between 1MHz and 10MHz in response to the helium temperature dependent properties showed an encouraging agreement with established theories, providing experimental verification on a new smaller length scale. The smallest beams achieved a mass sensitivity in liquid of 10ag. We also created and analysed a new method of sampling peak-like functions that is applicable to many physical systems to provide around 20% improvements over the existing methods under certain situations. This was verified in ultra low temperature applications as a drop-in addition to accompany existing techniques

Mass spectrometry imaging of glucosinolates in arabidopsis flowers and siliques

Glucosinolates are multi-functional plant secondary metabolites which play a vital role in plant defence and are, as dietary compounds, important to human health and livestock well-being. Knowledge of the tissue-specific regulation of their biosynthesis and accumulation is essential for plant breeding programs. Here, we report that in Arabidopsis thaliana, glucosinolates are accumulated differentially in specific cells of reproductive organs. Using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI), distribution patterns of three selected compounds, 4-methylsulfinylbutyl (glucoraphanin), indol-3-ylmethyl (glucobrassicin), and 4-benzoyloxybutyl glucosinolates, were mapped in the tissues of whole flower buds, sepals and siliques. The results show that tissue localization patterns of aliphatic glucosinolate glucoraphanin and 4-benzoyloxybutyl glucosinolate were similar, but indole glucosinolate glucobrassicin had different localisation, indicating a possible difference in function. The high resolution images obtained by a complementary approach, cryo-SEM Energy Dispersive X-ray analysis (cryo-SEM-EDX), confirmed increased concentration of sulphur in areas with elevated amounts of glucosinolates, and allowed identifying the cell types implicated in accumulation of glucosinolates. High concentration of sulphur was found in S-cells adjacent to the phloem in pedicels and siliques, indicating the presence of glucosinolates. Moreover, both MALDI MSI and cryo-SEM-EDX analyses indicated accumulation of glucosinolates in cells on the outer surface of the sepals, suggesting that a layer of glucosinolate-accumulating epidermal cells protects the whole of the developing flower, in addition to the S-cells, which protect the phloem. This research demonstrates the high potential of MALDI MSI for understanding the cell-specific compartmentation of plant metabolites and its regulation

Nanoelectronic thermometers optimised for sub-10 millikelvin operation

We report the cooling of electrons in nanoelectronic Coulomb blockade thermometers below 4 mK. Above 7 mK the devices are in good thermal contact with the environment, well isolated from electrical noise, and not susceptible to self-heating. This is attributed to an optimised design that incorporates cooling fins with a high electron-phonon coupling and on-chip electronic filters, combined with a low-noise electronic measurement setup. Below 7 mK the electron temperature is seen to diverge from the ambient temperature. By immersing a Coulomb Blockade Thermometer in the 3He/4He refrigerant of a dilution refrigerator, we measure a lowest electron temperature of 3.7 mK.Comment: 11 pages, 4 figures. (Fixed fitted saturation T_e on p9

Monitoring recombinant protein expression in bacteria by rapid evaporative ionisation mass spectrometry.

RATIONALE:There is increasing interest in methods of direct analysis mass spectrometry that bypass complex sample preparation steps. METHODS:One of the most interesting new ionisation methods is rapid evaporative ionisation mass spectrometry (REIMS) in which samples are vapourised and the combustion products are subsequently ionised and analysed by mass spectrometry (Synapt G2si). The only sample preparation required is the recovery of a cell pellet from a culture that can be analysed immediately. RESULTS:We demonstrate that REIMS can be used to monitor the expression of heterologous recombinant proteins in Escherichia coli. Clear segregation was achievable between bacteria harvesting plasmids that were strongly expressed and other cultures in which the plasmid did not result in the expression of large amounts of recombinant product. CONCLUSIONS:REIMS has considerable potential as a near-instantaneous monitoring tool for protein production in a biotechnology environment

Top-down and bottom-up identification of proteins by liquid extraction surface analysis mass spectrometry of healthy and diseased human liver tissue

Liquid extraction surface analysis mass spectrometry (LESA MS) has the potential to become a useful tool in the spatially-resolved profiling of proteins in substrates. Here, the approach has been applied to the analysis of thin tissue sections from human liver. The aim was to determine whether LESA MS was a suitable approach for the detection of protein biomarkers of nonalcoholic liver disease (nonalcoholic steatohepatitis, NASH), with a view to the eventual development of LESA MS for imaging NASH pathology. Two approaches were considered. In the first, endogenous proteins were extracted from liver tissue sections by LESA, subjected to automated trypsin digestion, and the resulting peptide mixture was analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) (bottom-up approach). In the second (top-down approach), endogenous proteins were extracted by LESA, and analyzed intact. Selected protein ions were subjected to collision-induced dissociation (CID) and/or electron transfer dissociation (ETD) mass spectrometry. The bottom-up approach resulted in the identification of over 500 proteins; however identification of key protein biomarkers, liver fatty acid binding protein (FABP1), and its variant (Thr→Ala, position 94), was unreliable and irreproducible. Top-down LESA MS analysis of healthy and diseased liver tissue revealed peaks corresponding to multiple (~15–25) proteins. MS/MS of four of these proteins identified them as FABP1, its variant, α-hemoglobin, and 10 kDa heat shock protein. The reliable identification of FABP1 and its variant by top-down LESA MS suggests that the approach may be suitable for imaging NASH pathology in sections from liver biopsies. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13361-014-0967-z) contains supplementary material, which is available to authorized users

Rapid identification of species, sex and maturity by mass spectrometric analysis of animal faeces

Background We describe a new approach to the recovery of information from faecal samples, based on the analysis of the molecular signature generated by rapid evaporative ionisation mass spectrometry (REIMS). Results Faecal pellets from five different rodent species were analysed by REIMS, and complex mass spectra were acquired rapidly (typically a few seconds per sample). The uninterpreted mass spectra (signatures) were then used to seed linear discriminant analysis and classification models based on random forests. It was possible to classify each species of origin with a high rate of accuracy, whether faeces were from animals maintained under standard laboratory conditions or wild-caught. REIMS signatures were stable to prior storage of the faecal material under a range of different conditions and were not altered rapidly or radically by changes in diet. Further, within species, REIMS signatures could be used to discriminate faeces from adult versus juvenile mice, male versus female mice and those from three different laboratory strains. Conclusions REIMS offers a completely novel method for the rapid analysis of faecal samples, extending faecal analysis (previously focused on DNA) to an assessment of phenotype, and has considerable potential as a new tool in the armamentarium of the field biologist