Experimental Deployment of Microbial Mineral Carbonation at an Asbestos Mine: Potential Applications to Carbon Storage and Tailings Stabilization

A microbial mineral carbonation trial was conducted at the Woodsreef Asbestos Mine (NSW, Australia) to test cyanobacteria-accelerated Mg-carbonate mineral precipitation in mine tailings. The experiment aimed to produce a carbonate crust on the tailings pile surface using atmospheric carbon dioxide and magnesium from serpentine minerals (asbestiform chrysotile; Mg3Si2O5(OH)4) and brucite [Mg(OH)2]. The crust would serve two purposes: Sequestering carbon and stabilizing the hazardous tailings. Two plots (0.5 m3) on the tailings pile were treated with sulfuric acid prior to one plot being inoculated with a cyanobacteria-dominated consortium enriched from the mine pit lakes. After 11 weeks, mineral abundances in control and treated tailings were quantified by Rietveld refinement of powder X-ray diffraction data. Both treated plots possessed pyroaurite [Mg6Fe2(CO3)(OH)16·4H2O] at 2 cm depth, made visible by its orange-red color. The inoculated plot exhibited an increase in the hydromagnesite [Mg5(CO3)4(OH)2·4H2O] content from 2–4 cm depth. The degree of mineral carbonation was limited compared to previous experiments, revealing the difficulty of transitioning from laboratory conditions to mine-site mineral carbonation. Water and carbon availability were limiting factors for mineral carbonation. Overcoming these limitations and enhancing microbial activity could make microbial carbonation a viable strategy for carbon sequestration in mine tailings

Fate of transition metals during passive carbonation of ultramafic mine tailings via air capture with potential for metal resource recovery

Mineral carbonation in ultramafic mine tailings is generally accepted to be a safe and long term means of trapping and storing CO2 within the structures of minerals, but it poses the risk of releasing potentially hazardous metal contaminants from mineral wastes into the environment. Stockpiles of reactive, finely pulverised ultramafic mine tailings are ideal natural laboratories for the observation and promotion of the carbonation of Mg-silicate and Mg-hydroxide waste minerals via reaction with atmospheric or industrial CO2. However, ultramafic mine tailings commonly contain first-row transition metals (e.g., Cr, Co, Cu, Ni) in potentially toxic concentrations within the crystal structures of Mg-silicates, sulphides, and oxides. These transition metals are likely to be mobilised by mineral carbonation reactions, which require mineral dissolution to supply cations for reaction with carbon. At Woodsreef Chrysotile Mine, New South Wales, Australia, transition metals (i.e., Fe, Cr, Ni, Mn, Co, Cu) are most concentrated within minor oxides (magnetite and chromite) and trace alloys (awaruite, Ni2-3Fe and wairauite, CoFe) in serpentine tailings, however, mobilisation of transition metals appears to occur predominantly during dissolution of serpentine and brucite, which are more abundant and reactive phases, respectively. Here, we present new synchrotron X-ray fluorescence mapping data that provide insights into the mobility of first-row transition metals (Fe, Cr, Ni, Mn, Co, Cu) during weathering and carbonation of ultramafic mine tailings collected from the Woodsreef Chrysotile Mine. These data indicate that the recently precipitated carbonate minerals, hydromagnesite [Mg5(CO3)4(OH)2·4H2O] and pyroaurite [Mg6Fe2(CO3)(OH)16·4H2O] sequester trace metals from the tailings at concentrations of 10 s–100 s of ppm, most likely via substitution for Mg or Fe within their crystal structures, or by the physical trapping of small (μm-scale) transition-metal-rich grains (i.e., magnetite, chromite, awaruite), which are stabilised within alkaline carbonate cements. Trace transition metals are present at relatively high concentrations in the bulk tailings (i.e., ∼0.3 wt.% NiO and Cr2O3) and they are largely retained within the unaltered mineral assemblage. The weathering products that occur at the surface of the tailings and form a cement between grains of partially dissolved gangue minerals immobilise transition metals on spatial scales of micrometres and at comparable concentrations to those observed in the unaltered tailings. The end result is that trace metals are not present at detectable levels within mine pit waters. Our observations of metal mobility during passive carbonation suggest that mineral products of accelerated carbonation treatments are likely to sequester trace metals. Thus, accelerated carbonation is unlikely to pose an environmental risk in the form of metalliferous drainage so long as the neutralisation potential of the tailings is not exceeded. Understanding both trace transition metal geochemistry and mineralogy within materials targeted for mineral carbonation could allow optimisation of treatment processes and design for recovery of valuable metals. In ex situ reactors employing acid pre-treatments, trace metals mobilised from reactive phases such as serpentine and brucite could potentially be recovered using pH-swing methods, while recalcitrant metal-rich accessory minerals, including magnetite, awaruite and chromite, could be recovered from treated residue material by conventional mineral separation processes. Recovery of valuable metals (i.e., Ni, Cr and Co) as by-products of accelerated mineral carbonation technologies could also provide an important economic incentive to support broader adoption of this technology

Ovarian cancer symptom awareness and anticipated delayed presentation in a population sample

Background: While ovarian cancer is recognised as having identifiable early symptoms, understanding of the key determinants of symptom awareness and early presentation is limited. A population-based survey of ovarian cancer awareness and anticipated delayed presentation with symptoms was conducted as part of the International Cancer Benchmarking Partnership (ICBP). Methods: Women aged over 50 years were recruited using random probability sampling (n = 1043). Computer-assisted telephone interviews were used to administer measures including ovarian cancer symptom recognition, anticipated time to presentation with ovarian symptoms, health beliefs (perceived risk, perceived benefits/barriers to early presentation, confidence in symptom detection, ovarian cancer worry), and demographic variables. Logistic regression analysis was used to identify the contribution of independent variables to anticipated presentation (categorised as < 3 weeks or ≥ 3 weeks). Results: The most well-recognised symptoms of ovarian cancer were post-menopausal bleeding (87.4%), and persistent pelvic (79.0%) and abdominal (85.0%) pain. Symptoms associated with eating difficulties and changes in bladder/bowel habits were recognised by less than half the sample. Lower symptom awareness was significantly associated with older age (p ≤ 0.001), being single (p ≤ 0.001), lower education (p ≤ 0.01), and lack of personal experience of ovarian cancer (p ≤ 0.01). The odds of anticipating a delay in time to presentation of ≥ 3 weeks were significantly increased in women educated to degree level (OR = 2.64, 95% CI 1.61 – 4.33, p ≤ 0.001), women who reported more practical barriers (OR = 1.60, 95% CI 1.34 – 1.91, p ≤ 0.001) and more emotional barriers (OR = 1.21, 95% CI 1.06 – 1.40, p ≤ 0.01), and those less confident in symptom detection (OR = 0.56, 95% CI 0.42 – 0.73, p ≤ 0.001), but not in those who reported lower symptom awareness (OR = 0.99, 95% CI 0.91 – 1.07, p = 0.74). Conclusions: Many symptoms of ovarian cancer are not well-recognised by women in the general population. Evidence-based interventions are needed not only to improve public awareness but also to overcome the barriers to recognising and acting on ovarian symptoms, if delays in presentation are to be minimised

Desferrioxamine decreases NAD redox potential of intact red blood cells: evidence for desferrioxamine as an inducer of oxidant stress in red blood cells

BACKGROUND: Desferrioxamine (DFO) is an important iron chelating agent. It has also been thought of as an agent with anti-oxidant potential as it chelates ferric iron in various parts of the body. However, there is evidence suggesting that it may paradoxically affect red blood cells (RBC) by inducing intracellular oxidant stress. To further understand the mechanism of DFO's interaction with RBC, we conducted a study to determine the effect of DFO upon RBC's redox status. METHODS: We examined NAD redox potential in intact RBC (N = 5) incubated with DFO. RBC were incubated with 6 mM DFO for 2 hours. RESULTS: Significant decreases in NAD redox potential were observed after incubation of RBC with 6 mM DFO. The mean decrease was 10.01 ± 1.98% (p < 0.0004). CONCLUSIONS: The data confirm the oxidant effect of DFO on RBC

Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged. © 2013 Lombardo et al

Coupled Analysis of In Vitro and Histology Tissue Samples to Quantify Structure-Function Relationship

The structure/function relationship is fundamental to our understanding of biological systems at all levels, and drives most, if not all, techniques for detecting, diagnosing, and treating disease. However, at the tissue level of biological complexity we encounter a gap in the structure/function relationship: having accumulated an extraordinary amount of detailed information about biological tissues at the cellular and subcellular level, we cannot assemble it in a way that explains the correspondingly complex biological functions these structures perform. To help close this information gap we define here several quantitative temperospatial features that link tissue structure to its corresponding biological function. Both histological images of human tissue samples and fluorescence images of three-dimensional cultures of human cells are used to compare the accuracy of in vitro culture models with their corresponding human tissues. To the best of our knowledge, there is no prior work on a quantitative comparison of histology and in vitro samples. Features are calculated from graph theoretical representations of tissue structures and the data are analyzed in the form of matrices and higher-order tensors using matrix and tensor factorization methods, with a goal of differentiating between cancerous and healthy states of brain, breast, and bone tissues. We also show that our techniques can differentiate between the structural organization of native tissues and their corresponding in vitro engineered cell culture models

Medication administration errors for older people in long-term residential care

Background Older people in long-term residential care are at increased risk of medication errors. The purpose of this study was to evaluate a computerised barcode medication management system designed to improve drug administrations in residential and nursing homes, including comparison of error rates and staff awareness in both settings. Methods All medication administrations were recorded prospectively for 345 older residents in thirteen care homes during a 3-month period using the computerised system. Staff were surveyed to identify their awareness of administration errors prior to system introduction. Overall, 188,249 attempts to administer medication were analysed to determine the prevalence of potential medication administration errors (MAEs). Error classifications included attempts to administer medication at the wrong time, to the wrong person or discontinued medication. Analysis compared data at residential and nursing home level and care and nursing staff groups. Results Typically each resident was exposed to 206 medication administration episodes every month and received nine different drugs. Administration episodes were more numerous (p < 0.01) in nursing homes (226.7 per resident) than in residential homes (198.7). Prior to technology introduction, only 12% of staff administering drugs reported they were aware of administration errors being averted in their care home. Following technology introduction, 2,289 potential MAEs were recorded over three months. The most common MAE was attempting to give medication at the wrong time. On average each resident was exposed to 6.6 potential errors. In total, 90% of residents were exposed to at least one MAE with over half (52%) exposed to serious errors such as attempts to give medication to the wrong resident. MAEs rates were significantly lower (p < 0.01) in residential homes than nursing homes. The level of non-compliance with system alerts was low in both settings (0.075% of administrations) demonstrating virtually complete error avoidance. Conclusion Potentially inappropriate administration of medication is a serious problem in long-term residential care. A computerised barcode system can accurately and automatically detect inappropriate attempts to administer drugs to residents. This tool can reliably be used by care staff as well as nurses to improve quality of care and patient safety

New insights into the classification and nomenclature of cortical GABAergic interneurons.

A systematic classification and accepted nomenclature of neuron types is much needed but is currently lacking. This article describes a possible taxonomical solution for classifying GABAergic interneurons of the cerebral cortex based on a novel, web-based interactive system that allows experts to classify neurons with pre-determined criteria. Using Bayesian analysis and clustering algorithms on the resulting data, we investigated the suitability of several anatomical terms and neuron names for cortical GABAergic interneurons. Moreover, we show that supervised classification models could automatically categorize interneurons in agreement with experts' assignments. These results demonstrate a practical and objective approach to the naming, characterization and classification of neurons based on community consensus

Visual ecology of aphids – a critical review on the role of colours in host finding

We review the rich literature on behavioural responses of aphids (Hemiptera: Aphididae) to stimuli of different colours. Only in one species there are adequate physiological data on spectral sensitivity to explain behaviour crisply in mechanistic terms. Because of the great interest in aphid responses to coloured targets from an evolutionary, ecological and applied perspective, there is a substantial need to expand these studies to more species of aphids, and to quantify spectral properties of stimuli rigorously. We show that aphid responses to colours, at least for some species, are likely based on a specific colour opponency mechanism, with positive input from the green domain of the spectrum and negative input from the blue and/or UV region. We further demonstrate that the usual yellow preference of aphids encountered in field experiments is not a true colour preference but involves additional brightness effects. We discuss the implications for agriculture and sensory ecology, with special respect to the recent debate on autumn leaf colouration. We illustrate that recent evolutionary theories concerning aphid–tree interactions imply far-reaching assumptions on aphid responses to colours that are not likely to hold. Finally we also discuss the implications for developing and optimising strategies of aphid control and monitoring