3,145 research outputs found
A GIS of the extent of historical mining activities in Scotland: explanatory notes
As part of the secondment of BGS staff to SEPA to help implement the Water Framework
Directive (WFD) in Scotland, BGS have been asked to provide an approximate outline of the
extent of historical mining in Scotland. This will be used to help characterize pressures on
Scottish groundwater as part of the initial characterization of groundwater bodies for the WFD.
Initial characterization has to be completed by December 2004; for bodies deemed to be at risk
there will be further characterization after 2004. A team of BGS geologists carried out the work
during September 2003.
The aim of the study was:
“To delineate the extent of known and inferred historical and current shallow and dee
Thermal near infrared monitoring system for electron beam melting with emissivity tracking
This paper presents the design of a high speed, high resolution silicon based thermal imaging instrument and its application to thermally image the temperature distributions of an electron beam melting additive manufacturing system. Typically, thermal images are produced at mid or long wavelengths of infrared radiation. Using the shorter wavelengths that silicon focal plane arrays are sensitive to allows the use of standard windows in the optical path. It also affords fewer modifications to the machine and enables us to make use of mature silicon camera technology. With this new instrument, in situ thermal imaging of the entire build area has been made possible at high speed, allowing defect detection and melt pool tracking. Melt pool tracking was used to implement an emissivity correction algorithm, which produced more accurate temperatures of the melted areas of the layer
Excited-State Dynamics of a Two-Photon-Activatable Ruthenium Prodrug
We present a new approach to investigate how the photodynamics of an octahedral ruthenium(II) complex activated through two-photon absorption (TPA) differ from the equivalent complex activated through one-photon absorption (OPA). We photoactivated a RuII polypyridyl complex containing bioactive monodentate ligands in the photodynamic therapy window (620–1000 nm) by using TPA and used transient UV/Vis absorption spectroscopy to elucidate its reaction pathways. Density functional calculations allowed us to identify the nature of the initially populated states and kinetic analysis recovers a photoactivation lifetime of approximately 100 ps. The dynamics displayed following TPA or OPA are identical, showing that TPA prodrug design may use knowledge gathered from the more numerous and easily conducted OPA studies
Situational awareness and safety
This paper considers the applicability of situation awareness concepts to safety in the control of complex systems. Much of the research to date has been conducted in aviation, which has obvious safety implications. It is argued that the concepts could be extended to other safety critical domains. The paper presents three theories of situational awareness: the three-level model, the interactive sub-systems approach, and the perceptual cycle. The difference between these theories is the extent to which they emphasise process or product as indicative of situational awareness. Some data from other studies are discussed to consider the negative effects of losing situational awareness, as this has serious safety implications. Finally, the application of situational awareness to system design, and training are presented
Thirty years after the Chernobyl accident: what lessons have we learnt?
April 2016 sees the 30th anniversary of the accident at the Chernobyl nuclear power plant. As a consequence of the accident populations were relocated in Belarus, Russia and Ukraine and remedial measures were put in place to reduce the entry of contaminants (primarily 134+137Cs) into the human food chain in a number of countries throughout Europe. Remedial measures are still today in place in a number of countries, and areas of the former Soviet Union remain abandoned.
The Chernobyl accident led to a large resurgence in radioecological studies both to aid remediation and to be able to make future predictions on the post-accident situation, but, also in recognition that more knowledge was required to cope with future accidents. In this paper we discuss, what in the authors' opinions, were the advances made in radioecology as a consequence of the Chernobyl accident.
The areas we identified as being significantly advanced following Chernobyl were: the importance of semi-natural ecosystems in human dose formation; the characterisation and environmental behaviour of ‘hot particles'; the development and application of countermeasures; the “fixation” and long term bioavailability of radiocaesium and; the effects of radiation on plants and animals
Evaluation of C-reactive protein and haptoglobin as malaria episode markers in an area of high transmission in Africa
Field studies of malaria in endemic areas frequently use the presence or levels of parasitaemia, together with the measurement of fever, as the primary criteria with which to identify cases. However, since malaria cases do not always present with measurable fever, and since asymptomatic parasitaemia occurs, additional episode markers might be useful epidemiological tools. We have measured the C-reactive protein and haptoglobin levels in paediatric patients presenting to a village health post in the Kilombero District in Tanzania and in convalescent sera from the same patients, in order to evaluate these acute-phase reactants as alternative markers of Plasmodium falciparum episodes. Among afebrile patients, C-reactive protein levels were highly correlated with parasite density. High C-reactive protein levels are therefore probably indicative of recent clinical malaria episodes in currently afebrile individuals with high parasite densities. An appropriate case definition for malaria in epidemiological studies in endemic areas might therefore be hyperparasitaemia accompanied by either, or both, measurable fever and raised C-reactive protein levels. This would give less biased estimates of the overall burden of malaria morbidity than does a definition which requires measurable fever. Levels of haptoglobin were highly negatively correlated with parasitaemia, but did not appear to be useful episode markers because this correlation was probably not related to acute morbidity. However, haptoglobin can be useful to assess at community level the impact of interventions on parasitaemi
Inkjet printing magnetostrictive materials for structural health monitoring of carbon fibre-reinforced polymer composite
Inkjet printing of magnetic materials has increased in recent years, as it has the potential to improve research in smart, functional materials. Magnetostriction is an inherent property of magnetic materials which allows strain or magnetic fields to be detected. This makes it very attractive for sensors in the area of structural health monitoring by detecting internal strains in carbon fibre-reinforced polymer (CFRP) composite. Inkjet printing offers design flexibility for these sensors to influence the magnetic response to the strain. This allows the sensor to be tailored to suit the location of defects in the CFRP. This research has looked into the viability of printable soft magnetic materials for structural health monitoring (SHM) of CFRP. Magnetite and nickel ink dispersions were selected to print using the JetLab 4 drop-on-demand technique. The printability of both inks was tested by selecting substrate, viscosity and solvent evaporation. Clogging was found to be an issue for both ink dispersions. Sonicating and adjusting the jetting parameters helped in distributing the nanoparticles. We found that magnetite nanoparticles were ideal as a sensor as there is more than double increase in saturation magnetisation by 49 Am2/kg and more than quadruple reduction of coercive field of 5.34 kA/m than nickel. The coil design was found to be the most sensitive to the field as a function of strain, where the gradient was around 80% higher than other sensor designs. Additive layering of 10, 20 and 30 layers of a magnetite square patch was investigated, and it was found that the 20-layered magnetite print had an improved field response to strain while maintaining excellent print resolution. SHM of CFRP was performed by inducing a strain via bending and it was found that the magnetite coil detected a change in field as the strain was applied
Association Between Sarcopenia and Functional Status in Liver Transplant Patients
OBJECTIVES: A growing body of evidence shows that frailty and functional performance predict liver transplant outcomes. The Organ Procurement and Transplant Network uses the Karnofsky Performance Status scale to adjust for transplant center case mix in assessing quality measures. This study explores the strength of the relationship between Karnofsky Performance Status scores and objective measures of frailty.
MATERIALS AND METHODS: This observational study includes 136 adult, first-time liver transplant recipients at UMass Memorial (2006-2015) who had 2 abdominal computed tomography scans available (at \u3c /= 90 days pretransplant and \u3e /= 7 days before that). We analyzed the relationship between Karnofsky Performance Status and muscle wasting using absolute and change in psoas muscle size and quality pretransplant.
RESULTS: The mean age was 55 years, mean Model for End-Stage Liver Disease was 22, and 34% of patients were women. In the study group, 50% of patients had sarcopenia pretransplant and 71.3% demonstrated declined lean psoas area at an average rate of 11% per month. Patients who experienced muscle wasting at a rate of \u3e /= 1% per month had 2.83 times the risk (95% confidence interval, 1.18-6.80) of being severely impaired/disabled pretransplant. The risk increased by 2.32-fold (95% confidence interval, 1.44-3.75) for every standard deviation decrease in pretransplant lean psoas area.
CONCLUSIONS: Provider-assessed physical health status moderately correlates with objective measures of frailty
The cDNA-deduced primary structure of human sex hormone-binding globulin and location of its steroid-binding domain
AbstractWe have sequenced a cDNA for sex hormone-binding globulin (SHBG) isolated from a phage λgt 11 human liver cDNA library. The library was screened with a radiolabeled rat androgen-binding protein (ABP) cDNA, and the abundance of SHBG cDNAs was 1 in 750 000 plaques examined. The largest human SHBG cDNA (1194 base-pairs) contained a reading frame for 381 amino acids. This comprised 8 amino acids of a signal peptide followed by 373 residues starting with the known NH2-terminal sequence of human SHBG, and ending with a termination codon. The predicted polypeptide Mr of SHBG is 40 509, and sites of attachment of one O-linked (residue 7) and two N-linked oligosaccharide (residues 351 and 367) chains were identified. Purified SHBG was photoaffinity-labeled with Δ6-[3H]testosterone and cleaved with trypsin. The labeled tryptic fragment was isolated by reverse-phase HPLC, and its NH2-terminal sequence was determined. The results suggest that a portion of the steroid-binding domain of SHBG is located between residue 296 and the 35 predominantly hydrophilic residues at the C-terminus of the protein
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