Electroanalytical determination of trace chloride in room-temperature ionic liquids

The electroanalytical quantification of chloride in [C(4)mim][BF4], [C(4)mim][NTf2] and [C(4)mim][PF6] ionic liquids has been explored using linear sweep and square wave voltammetry. Cathodic stripping voltammetry at a silver disk electrode is found to be the most sensitive. The methodology is based on first holding the potential of the electrode at +2.0 V (vs Ag wire), to accumulate silver chloride at the electrode. On applying a cathodic scan, a stripping wave is observed corresponding to the reduction of the silver chloride. This stripping protocol was found to detect ppb levels of chloride in [C(4)mim][BF4], [C(4)mim][NTf2], and [C(4)mim][PF6]. Although other methods for chloride have been reported for [BF4](-)- and [PF6](-)-based ionic liquids, no methods have been reported for [NTf2](-) ionic liquids.

High incidence of cryptic repeated elements in microsatellite flanking regions of galatheid genomes and its evolutionary implications

During the development of PCR primer sets for icrosatellite marker loci from enriched genomic libraries for three squat lobster species from Galatheidae (Decapoda: Anomura); Munida rugosa (Fabricius, 1775), M. sarsi (Huus, 1935), and Galathea strigosa (Linnaeus, 1761) (collectively known as squat lobsters), a number of unforeseen problems were encountered. These included PCR amplification failure, lack of amplification consistency, and the amplification of multiple fragments. Careful examination of microsatellite containing sequences revealed the existence of cryptic repeated elements on presumed unique flanking regions. BLAST analysis of these and other VNTR containing sequences (N 5 252) indicates that these cryptic elements can be grouped into families based upon sequence similarities. The unique features characterising these families suggest that different molecular mechanisms are involved. Of particular relevance is the association of microsatellites with mobile elements. This is the first reported observation of this phenomenon in crustaceans, and it also helps to explain why microsatellite primer development in galatheids has been relatively unsuccessful to date. We suggest a number of steps that can be used to identify similar problems in microsatellite marker development for other species, and also alternative approaches for both marker development and for the study of molecular evolution of species characterised by complex genome organisation. More specifically, we argue that new generation sequencing methodologies, which capitalise on parallel and multiplexed sequencing may pave the way forward for future crustacean research.

SEROTONINERGIC AND PEPTIDERGIC NERVE ELEMENTS IN THE PROTOSCOLEX OF ECHINOCOCCUS-GRANULOSUS (CESTODA, CYCLOPHYLLIDEA)

The localisation and distribution of 5-hydroxytryptamine (5-HT, or serotonin) and neuropeptides in the nervous system of the protoscolex of the hydatid organism Echinococcus granulosus were determined by an indirect immunofluorescence technique. Nerve-cell bodies immunoreactive for 5-HT occurred in the lateral ganglia and in association with the lateral longitudinal nerve cords. 5-HT immunostaining was also evident in the central nerve ring, in the rostellar nerves and in the nerve plexus innervating the suckers. Of the antisera used to screen the protoscolex for neuropeptide immunoreactivity (IR), immunostaining was obtained with those raised against pancreatic polypeptide (PP), peptide YY (PYY), substance P (SP), peptide histidine isoleucine (PI-II) and vasoactive intestinal peptide (VIP). The most extensive pattern of IR occurred with antisera to PP and PYY. Immunoreactive nerve elements were evident in the lateral ganglia, central nerve ring, rostellar nerves, rostellar ganglia, sucker plexus and longitudinal nerve cords. The distribution of SP-, PHI- and VIP-IRs was more restricted: SP-IR occurred in the lateral ganglia and sucker nerves, whilst PHI- and VIP-immunoreactive nerve elements were associated with the lateral longitudinal nerve cords. Protoscoleces cultured in vitro for 29 days were also examined and neuroanatomical changes noted. A greater development of the longitudinal nerve cords and their cross-connectives in the body of the worm was evident, and a group of nerve cells were seen to develop at the posterior end of the main lateral nerve cords.

Toenail trace element status and risk of Barrett's oesophagus and oesophageal adenocarcinoma. Results from the FINBAR study

Trace elements have been cited as both inhibitory and causative agents of cancer but importantly exposure to them is potentially modifiable. Our study aimed to examine toenail trace element status and risk of Barrett's oesophagus (BO) and oesophageal adenocarcinoma (OAC). Toenail clippings from each hallux were obtained from 638 participants of the FINBAR (Factors Influencing the Barrett's Adenocarcinoma Relationship) study comprising 221 healthy controls, 98 reflux oesophagitis, 182 BO and 137 OAC cases. The concentrations of eight toenail trace elements were determined using instrumental neutron activation analysis. Using multivariable adjusted logistic regression analysis, odds ratios (OR) and 95% confidence intervals (CIs) were calculated within tertiles of trace element concentrations. A twofold increased risk of BO was observed, but not OAC, among individuals in the highest tertile of toenail zinc status OR 2.21 (95% CI, 1.11-4.40). A higher toenail selenium status was not associated with risk of OAC OR 0.94 (95% CI, 0.44-2.04) or BO OR 0.89 (95% CI, 0.37-2.12). A borderline significant increased risk of BO was detected with a higher toenail cobalt concentration, OR 1.97 (95% CI, 1.01-3.85). No association was found between toenail levels of chromium, cerium, mercury and OAC or BO risk. This is the first case-control study to investigate a variety of trace elements in relation to OAC and BO risk. Despite antioxidant and proapoptotic properties, no associations were found with selenium. Higher concentrations of toenail zinc and cobalt were associated with an increased BO risk, but not OAC. These findings need confirmation in prospective analysis.

CYTOCHEMICAL DEMONSTRATION OF CHOLINERGIC, SEROTONINERGIC AND PEPTIDERGIC NERVE ELEMENTS IN GORGODERINA-VITELLILOBA (TREMATODA, DIGENEA)

Standard enzyme cytochemical and indirect immunocytochemical techniques have been used in conjunction with light and confocal scanning laser microscopy (CSLM) to visualize cholinergic, serotoninergic and peptidergic nerve elements in whole-mount preparations of the amphibian urinary-bladder fluke, Gorgoderina vitelliloba. Cholinesterase (ChE) activity was localized in paired anterior ganglia, a connecting dorsal commissure and in the origins of the ventral nerve cords. Cholinergic ganglia were also evident in shelled embryos in the uterus. Serotonin-immunoreactivity (IR) was more extensive than ChE activity and was identified in both the central and peripheral nervous systems. Serotoninergic nerve fibres were associated with the somatic musculature and female reproductive ducts. Antisera to nine mammalian peptides and one invertebrate (FMRFamide) peptide have been used to investigate the peptidergic nervous system in the parasite. Immunoreactivity was obtained to five peptides, namely pancreatic polypeptide (PP), peptide YY (PYY), neuropeptide Y (NPY), substance P (SP) and FMRFamide. Peptidergic nerve fibres were found to be more abundant than demonstrable cholinergic or serotoninergic nerve fibres. NPY-IR was identified only in the main components of the central nervous system. However, PP- and PYY-IR occurred in the anterior ganglia, dorsal commissure, main nerve cords and in numerous small varicose fibres that ramified throughout the worm. Additionally, PP-immunoreactive nerve fibres were found to innervate the musculature of the female reproductive tracts. Six sites of IR were found in the acetabulum, using antisera directed towards the C-terminal end of PP and PYY, and these matched with the distribution of six non-ciliated rosette-like papillae observed by scanning electron microscopy. SP- and FMRFamide-IR were identified in the CNS, and FMRFamide-immunopositive nerve fibres were also evident in association with the gonopore/cirrus region and with the terminal excretory pore. Results are discussed with respect to possible roles for each of the neurochemical types.

Risk assessment of potentially toxic elements in agricultural soils and maize tissues from selected districts in Tanzania

A field survey was conducted to investigate the contamination of potentially toxic elements (PTEs) arsenic (As), lead (Pb), chromium (Cr), and nickel (Ni) in Tanzanian agricultural soils and to evaluate their uptake and translocation in maize as proxy to the safety of maize used for human and animal consumption. Soils and maize tissues were sampled from 40 farms in Tanzania and analyzed using inductively coupled plasma-mass spectrometry in the United Kingdom. The results showed high levels of PTEs in both soils and maize tissues above the recommended limits. Nickel levels of up to 34.4 and 56.9mgkg(-1) respectively were found in some maize shoots and grains from several districts. Also, high Pb levels >0.2mgkg(-1) were found in some grains. The grains and shoots with high levels of Ni and Pb are unfit for human and animal consumption. Concentrations of individual elements in maize tissues and soils did not correlate and showed differences in uptake and translocation. However, Ni showed a more efficient transfer from soils to shoots than As, Pb and Cr. Transfer of Cr and Ni from shoots to grains was higher than other elements, implying that whatever amount is assimilated in maize shoots is efficiently mobilized and transferred to grains. Thus, the study recommended to the public to stop consuming and feeding their animals maize with high levels of PTEs for their safety.

Application of fibre assemblies as damping elements in the automotive industry

This investigation aims to characterise the damping properties of the nonwoven materials with potential applications in automotive and aerospace industry. Nonwovens are a popular choice for many applications due to their relatively low manufacturing cost and unique properties. It is known that nonwovens are efficient energy dispersers for certain applications such as acoustic damping and ballistic impact. It is anticipated that these energy absorption properties could eventually be used to provide damping for mechanical vibrations. However the behaviour of nonwovens under dynamic load and vibration has not been investigated before. Therefore we intend to highlight these aspects of the behaviour of the nonwovens through this research. In order to obtain an insight to the energy absorption properties of the nonwoven fabrics, a range of tests has been performed. Forced vibration of the cantilever beam is used to explore damping over a range of resonance modes and input amplitudes. The tests are conducted on aramid, glass fibre and polyester fabrics with a range of area densities and various coatings. The tests clarified the general dynamic behaviour of the fabrics tested and the possible response in more real application condition as well. The energy absorption in both thickness and plane of the fabric is tested. The effects of the area density on the results are identified. The main absorption mechanism is known to be the friction. The frictional properties are improved by using a smaller fibre denier and increasing fibre length, this is a result of increasing contact surface between fibres. It is expected the increased friction result in improving damping. The results indicate different mechanism of damping for fiber glass fabrics compared to the aramid fabrics. The frequency of maximum efficiency of damping is identified for the fabrics tested. These can be used to recommend potential applications.

Comparison of methods used to calculate typical threshold values for potentially toxic elements in soil

The environmental quality of land can be assessed by calculating relevant threshold values, which differentiate between concentrations of elements resulting from geogenic and diffuse anthropogenic sources and concentrations generated by point sources of elements. A simple process allowing the calculation of these typical threshold values (TTVs) was applied across a region of highly complex geology (Northern Ireland) to six elements of interest; arsenic, chromium, copper, lead, nickel and vanadium. Three methods for identifying domains (areas where a readily identifiable factor can be shown to control the concentration of an element) were used: k-means cluster analysis, boxplots and empirical cumulative distribution functions (ECDF). The ECDF method was most efficient at determining areas of both elevated and reduced concentrations and was used to identify domains in this investigation. Two statistical methods for calculating normal background concentrations (NBCs) and upper limits of geochemical baseline variation (ULBLs), currently used in conjunction with legislative regimes in the UK and Finland respectively, were applied within each domain. The NBC methodology was constructed to run within a specific legislative framework, and its use on this soil geochemical data set was influenced by the presence of skewed distributions and outliers. In contrast, the ULBL methodology was found to calculate more appropriate TTVs that were generally more conservative than the NBCs. TTVs indicate what a "typical" concentration of an element would be within a defined geographical area and should be considered alongside the risk that each of the elements pose in these areas to determine potential risk to receptors.

Trace Element Abundance and Renal Disease

This research investigates the relationship between elevated trace elements in soils, stream sediments and stream water and the prevalence of Chronic Kidney Disease (CKD). The study uses a collaboration of datasets provided from the UK Renal Registry Report (UKRR) on patients with renal diseases requiring treatment including Renal Replacement Therapy (RRT), the soil geochemical dataset for Northern Ireland provided by the Tellus Survey, Geological Survey of Northern Ireland (GSNI) and the bioaccessibility of Potentially Toxic Elements (PTEs) from soil samples which were obtained from the Unified Barge Method (UBM). The relationship between these factors derives from the UKRR report which highlights incidence rates of renal impaired patients showing regional variation with cases of unknown aetiology. Studies suggest a potential cause of the large variation and uncertain aetiology is associated with underlying environmental factors such as the oral bioaccessibility of trace elements in the gastrointestinal tract.
As previous research indicates that long term exposure is related to environmental factors, Northern Ireland is ideally placed for this research as people traditionally live in the same location for long periods of time. Exploratory data analysis and multivariate analyses are used to examine the soil, stream sediments and stream water geochemistry data for a range of key elements including arsenic, lead, cadmium and mercury identified from a review of previous renal disease literature. The spatial prevalence of patients with long term CKD is analysed on an area basis. Further work includes cluster analysis to detect areas of low or high incidences of CKD that are significantly correlated in space, Geographical Weighted Regression (GWR) and Poisson kriging to examine locally varying relationship between elevated concentrations of PTEs and the prevalence of CKD.