ABSTRACT Coeliac disease (CD), a T-cell-mediated gluten sensitive enteropathy, affects ~1% of the... more ABSTRACT Coeliac disease (CD), a T-cell-mediated gluten sensitive enteropathy, affects ~1% of the UK population, and in adults presents with a wide range of clinical features; often mistaken for irritable bowel syndrome (IBS). Heightened clinical awareness and serological screening identifies those likely to have CD; the diagnosis confirmed by histological features in small bowel/duodenal biopsies. Limitations to diagnosis are false negative serology (e.g., in IgA deficient patients, the young and the elderly) and reluctance to undergo biopsy. Examining the pattern of urinary volatiles offers a novel non-invasive approach. The gut microbiome is perturbed in several gastrointestinal disorders, resulting in altered gut fermentation patterns, and recognisable by analysis of volatile organic compounds (VOC) in urine, breath and faeces. The altered structure of the small intestinal mucosa, increased gut permeability and altered gluten peptide metabolism, we hypothesised, would change the microbiome creating a unique "fermentome" pattern, distinguishable from IBS. We investigated this by examining the urinary VOC pattern using Field Asymmetric Ion Mobility Spectrometry (FAIMS). gutjnl;63/Suppl_1/A110-a/F1F1F1 Abstract PTU-163 Figure 1 METHODS: 47 patients were recruited, 27 with CD and 20 with diarrhoea-predominant IBS (D-IBS). Urine was collected and 10ml aliquots were stored frozen in universal containers. For assay, the containers were heated to 40 ± 0.1(o)C. The headspace above the sample was then analysed by FAIMS. Linear discriminant analysis (LDA) was used for statistical evaluation.
ABSTRACT Squamous oesophageal carcinoma is more prevalent in those with lower socio-economic stat... more ABSTRACT Squamous oesophageal carcinoma is more prevalent in those with lower socio-economic status. Little is known about this for oesophageal adenocarcinoma (OAC). Anecdotally, OAC has been observed in higher socio-economic groups. Barrett's oesophagus (BO) is the only known precursor of OAC. This study investigates the association between BO and social deprivation using the 2010 Index of Multiple Deprivation (IMD).
The effect of an electric field on conduction in a disordered system is an old but largely unsolv... more The effect of an electric field on conduction in a disordered system is an old but largely unsolved problem. Experiments cover an wide variety of systems - amorphous/doped semiconductors, conducting polymers, organic crystals, manganites, composites, metallic alloys, double perovskites - ranging from strongly localized systems to weakly localized ones, from strongly correlated ones to weakly correlated ones. Theories have singularly failed to predict any universal trend resulting in separate theories for separate systems. Here we discuss a recent one-parameter scaling that has been found to give a systematic account of the field-dependent conductance in two strongly localized systems of conducting polymers and manganites. The nonlinearity exponent, \textit{x} associated with the scaling was unexpectedly found to possess multiple values. We find that the scaling applies to all other systems as mentioned. For 3D strongly localized systems the exponent lies between -1 and 1, and surpri...
A new scaling formalism is used to analyze nonlinear \textit{I-V} data in the vicinity of metal-i... more A new scaling formalism is used to analyze nonlinear \textit{I-V} data in the vicinity of metal-insulator transitions (MIT) in five manganite systems. An exponent, called nonlinearity exponent, and an onset field for nonlinearity, both characteristic of the system under study, are obtained from the analysis. The onset field is found to have an anomalously low value corroborating the theoretically predicted electronically soft phases. The scaling functions above and below the MIT of a polycrystalline sample are found to be same but with different exponents which are attributed to the distribution of the MIT temperatures. The existence of field scales in manganites underlines the universality of the assumed scaling form in disordered systems.
Nonlinear charge conduction in an organized assembly of lipid molecules has long been established... more Nonlinear charge conduction in an organized assembly of lipid molecules has long been established. However, the exact mechanism of charge transport across them is still not very clear. Since resistance involves the second moment of the current distribution, while noise involves the fourth moment, the noise measurement should be more informative about the underlying mechanism of charge transport. Using this
For a non percolating network of conductors, the insulation breakdown voltage VB vanishes near cc... more For a non percolating network of conductors, the insulation breakdown voltage VB vanishes near cc, the percolation threshold for conductors, as (cc-c)t'. Using a small-cell real-space renormalisation group technique (with scale factor b up to 3) the authors find t' approximately=0.9 for d=2. A Monte Carlo estimate for 20*20 square (bond-diluted) and triangular (site-diluted) lattices gives t'=0.8+or-0.1. The breakdown universality classes for such metal-insulator transition are also discussed.
At a composition far above the percolation threshold, the resistance of a composite sample increa... more At a composition far above the percolation threshold, the resistance of a composite sample increases with time due to Joule heating as a constant current of a sufficiently large value is passed through the sample. If the current is less than a certain breakdown current (I(b)) the resistance eventually reaches a steady value with a characteristic relaxation time tau(h). The latter diverges with current I as tau(h) approximately (1-I(2)/I(2)(b))(-z). The value of the exponent z displays large fluctuations leading to unusual scaling of the relaxation time. It is shown that the results lead to important conclusions about the nature of breakdown phenomena.
ABSTRACT Coeliac disease (CD), a T-cell-mediated gluten sensitive enteropathy, affects ~1% of the... more ABSTRACT Coeliac disease (CD), a T-cell-mediated gluten sensitive enteropathy, affects ~1% of the UK population, and in adults presents with a wide range of clinical features; often mistaken for irritable bowel syndrome (IBS). Heightened clinical awareness and serological screening identifies those likely to have CD; the diagnosis confirmed by histological features in small bowel/duodenal biopsies. Limitations to diagnosis are false negative serology (e.g., in IgA deficient patients, the young and the elderly) and reluctance to undergo biopsy. Examining the pattern of urinary volatiles offers a novel non-invasive approach. The gut microbiome is perturbed in several gastrointestinal disorders, resulting in altered gut fermentation patterns, and recognisable by analysis of volatile organic compounds (VOC) in urine, breath and faeces. The altered structure of the small intestinal mucosa, increased gut permeability and altered gluten peptide metabolism, we hypothesised, would change the microbiome creating a unique "fermentome" pattern, distinguishable from IBS. We investigated this by examining the urinary VOC pattern using Field Asymmetric Ion Mobility Spectrometry (FAIMS). gutjnl;63/Suppl_1/A110-a/F1F1F1 Abstract PTU-163 Figure 1 METHODS: 47 patients were recruited, 27 with CD and 20 with diarrhoea-predominant IBS (D-IBS). Urine was collected and 10ml aliquots were stored frozen in universal containers. For assay, the containers were heated to 40 ± 0.1(o)C. The headspace above the sample was then analysed by FAIMS. Linear discriminant analysis (LDA) was used for statistical evaluation.
ABSTRACT Squamous oesophageal carcinoma is more prevalent in those with lower socio-economic stat... more ABSTRACT Squamous oesophageal carcinoma is more prevalent in those with lower socio-economic status. Little is known about this for oesophageal adenocarcinoma (OAC). Anecdotally, OAC has been observed in higher socio-economic groups. Barrett's oesophagus (BO) is the only known precursor of OAC. This study investigates the association between BO and social deprivation using the 2010 Index of Multiple Deprivation (IMD).
The effect of an electric field on conduction in a disordered system is an old but largely unsolv... more The effect of an electric field on conduction in a disordered system is an old but largely unsolved problem. Experiments cover an wide variety of systems - amorphous/doped semiconductors, conducting polymers, organic crystals, manganites, composites, metallic alloys, double perovskites - ranging from strongly localized systems to weakly localized ones, from strongly correlated ones to weakly correlated ones. Theories have singularly failed to predict any universal trend resulting in separate theories for separate systems. Here we discuss a recent one-parameter scaling that has been found to give a systematic account of the field-dependent conductance in two strongly localized systems of conducting polymers and manganites. The nonlinearity exponent, \textit{x} associated with the scaling was unexpectedly found to possess multiple values. We find that the scaling applies to all other systems as mentioned. For 3D strongly localized systems the exponent lies between -1 and 1, and surpri...
A new scaling formalism is used to analyze nonlinear \textit{I-V} data in the vicinity of metal-i... more A new scaling formalism is used to analyze nonlinear \textit{I-V} data in the vicinity of metal-insulator transitions (MIT) in five manganite systems. An exponent, called nonlinearity exponent, and an onset field for nonlinearity, both characteristic of the system under study, are obtained from the analysis. The onset field is found to have an anomalously low value corroborating the theoretically predicted electronically soft phases. The scaling functions above and below the MIT of a polycrystalline sample are found to be same but with different exponents which are attributed to the distribution of the MIT temperatures. The existence of field scales in manganites underlines the universality of the assumed scaling form in disordered systems.
Nonlinear charge conduction in an organized assembly of lipid molecules has long been established... more Nonlinear charge conduction in an organized assembly of lipid molecules has long been established. However, the exact mechanism of charge transport across them is still not very clear. Since resistance involves the second moment of the current distribution, while noise involves the fourth moment, the noise measurement should be more informative about the underlying mechanism of charge transport. Using this
For a non percolating network of conductors, the insulation breakdown voltage VB vanishes near cc... more For a non percolating network of conductors, the insulation breakdown voltage VB vanishes near cc, the percolation threshold for conductors, as (cc-c)t'. Using a small-cell real-space renormalisation group technique (with scale factor b up to 3) the authors find t' approximately=0.9 for d=2. A Monte Carlo estimate for 20*20 square (bond-diluted) and triangular (site-diluted) lattices gives t'=0.8+or-0.1. The breakdown universality classes for such metal-insulator transition are also discussed.
At a composition far above the percolation threshold, the resistance of a composite sample increa... more At a composition far above the percolation threshold, the resistance of a composite sample increases with time due to Joule heating as a constant current of a sufficiently large value is passed through the sample. If the current is less than a certain breakdown current (I(b)) the resistance eventually reaches a steady value with a characteristic relaxation time tau(h). The latter diverges with current I as tau(h) approximately (1-I(2)/I(2)(b))(-z). The value of the exponent z displays large fluctuations leading to unusual scaling of the relaxation time. It is shown that the results lead to important conclusions about the nature of breakdown phenomena.
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