SciCombinator

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Concept: Iron

148

For more than one century, hydrogen assisted degradation of metallic microstructures has been identified as origin for severe technical component failures but the mechanisms behind have not yet been completely understood so far. Any in-situ observation of hydrogen transport phenomena in microstructures will provide more details for further elucidation of these degradation mechanisms. A novel experiment is presented which is designed to elucidate the permeation behaviour of deuterium in a microstructure of duplex stainless steel (DSS). A hydrogen permeation cell within a TOF-SIMS instrument enables electrochemical charging with deuterium through the inner surface of the cell made from DSS. The outer surface of the DSS permeation cell exposed to the vacuum has been imaged by TOF-SIMS vs. increasing time of charging with subsequent chemometric treatment of image data. This in-situ experiment showed evidently that deuterium is permeating much faster through the ferrite phase than through the austenite phase. Moreover, a direct proof for deuterium enrichment at the austenite-ferrite interface has been found.

Concepts: Iron, Metallurgy, Steel, Austenite, Stainless steel, Nickel, Corrosion, Microstructure

147

Metals deposited into ecosystems are non-degradable and become one of the major toxic agents which accumulate in habitats. Thus, their concentration requires precise monitoring. To evaluate pollution around a chlor-alkali plant, a glass smelter, two power plants and a ceramic and porcelain factory, we selected terrestrial mosses with different life forms: the orthotropic and endohydric Polytrichum commune and plagiotropic and ectohydric Pleurozium schreberi. Metal concentrations were determined in both species growing together at sites situated at various distances approximately 0.75, 1.5, 3 and 6 km from polluters. MARS analysis evaluated different tendencies of both species for Cd, Co and Pb accumulation depending on the distance from the emitter. In P. schreberi, the concentration of these metals diminished relatively rapidly with an increasing distance from the emitter up to 3000 m and then stabilised. For P. commune, a steady decrease could be observed with increasing the distance up to 6000 m. PCCA ordination explained that both species from the vicinity of the chlor-alkali plant were correlated with the highest Co, Cr, Cu, Fe and Pb as well as Mn and Ni concentrations in their tissues. The mosses from sites closest to both power plants were correlated with the highest Cd and Zn concentrations. P. commune contained significantly higher Cd, Cr, Ni, Pb and Zn concentrations compared to P. schreberi. This may be caused by the lamellae found in the leaves of P. commune which increase the surface area of the possible aerial absorption of contaminants. Soil may also be an additional source of metals, and it affects the uptake in endohydric P. commune more than in ectohydric P. schreberi. However, the precise explanation of these relations needs further investigation.

Concepts: Iron, Plant, Metal, Copper, Pollution, Moss, Mosses, Polytrichum commune

144

Ferric citrate (FC) has demonstrated efficacy as a phosphate binder and reduces the requirements for erythropoiesis-stimulating agents (ESAs) and intravenous (IV) iron in dialysis patients. We developed a net budgetary impact model to evaluate FC vs. other phosphate binders from the vantage of a large dialysis provider. We used a Markov microsimulation model to simulate mutually referential longitudinal effects between serum phosphate and phosphate binder dose; categories of these defined health states. Health states probabilistically determined treatment attendance and utilization of ESA and IV iron. We derived model inputs from a retrospective analysis of incident phosphate binder users from a large dialysis organization (January 2011-June 2013) and incorporated treatment effects of FC from a phase III trial. The model was run over a 1-year time horizon. We considered fixed costs of providing dialysis; costs of administering ESA and IV iron; and payment rates for dialysis, ESAs, and IV iron. In the base-case model, FC had a net budgetary impact (savings) of +US$213,223/year per 100 patients treated vs. standard of care. One-way sensitivity analyses showed a net budgetary impact of up to +US$316,296/year per 100 patients treated when higher hemoglobin levels observed with FC translated into a 30% additional ESA dose reduction, and up to +US$223,281/year per 100 patients treated when effects on missed treatment rates were varied. Two-way sensitivity analyses in which acquisition costs for ESA and IV iron were varied showed a net budgetary impact of +US$104,840 to +US$213,223/year per 100 patients treated. FC as a first-line phosphate binder would likely yield substantive savings vs. standard of care under current reimbursement.

Concepts: Nephrology, Iron, Retrospective, Calcium carbonate, Das Model, Renal osteodystrophy, Phosphate binders, Hyperphosphatemia

139

We show in this report that traces of juices released from salad leaves as they became damaged can significantly enhance Salmonella enterica salad leaf colonisation. Salad juices in water increased Salmonella growth by 110% over the un-supplemented control, and in host-like serum based media by more than 2400-fold over controls. In serum based media salad juices induced growth of Salmonella via provision of Fe from transferrin, and siderophore production was found to be integral to the growth induction process. Other aspects relevant to salad leaf colonisation and retention were enhanced, such as motility and biofilm formation, which increased over controls by >220% and 250% respectively; direct attachment to salad leaves increased by >350% when a salad leaf juice was present. In terms of growth and biofilm formation the endogenous salad leaf microbiota was largely unresponsive to leaf juice, suggesting that Salmonella gains a marked advantage from fluids released from salad leaf damage. Salad leaf juices also enhanced pathogen attachment to the salad bag plastic. Over 5 days refrigeration (a typical storage time for bagged salad leaves) even traces of juice within the salad bag fluids increased Salmonella growth in water by up to 280-fold over control cultures, as well as enhancing salad bag colonisation, which could be an unappreciated factor in pathogen fresh produce retention. Collectively, this study shows that exposure to salad leaf juice may contribute to the persistence of Salmonella on salad leaves, and strongly emphasizes the importance of ensuring the microbiological safety of fresh produce.

Concepts: Bacteria, Iron, Microbiology, Salmonella enterica, Salmonella, Leaf, Lettuce, Leaf vegetable

137

There has been no evidence for the necessity of endoscopy in asymptomatic young men with iron deficiency anemia (IDA). To determine whether endoscopy should be recommended in asymptomatic young men with IDA, we compared the prevalence of gastrointestinal (GI) lesions between young men (< 50 years) with IDA and those without IDA.

Concepts: Hemoglobin, Iron, Hematology, Iron deficiency anemia, Transferrin, Human iron metabolism, Iron deficiency, Serum iron

123

Decarbonization of electricity generation can support climate-change mitigation and presents an opportunity to address pollution resulting from fossil-fuel combustion. Generally, renewable technologies require higher initial investments in infrastructure than fossil-based power systems. To assess the tradeoffs of increased up-front emissions and reduced operational emissions, we present, to our knowledge, the first global, integrated life-cycle assessment (LCA) of long-term, wide-scale implementation of electricity generation from renewable sources (i.e., photovoltaic and solar thermal, wind, and hydropower) and of carbon dioxide capture and storage for fossil power generation. We compare emissions causing particulate matter exposure, freshwater ecotoxicity, freshwater eutrophication, and climate change for the climate-change-mitigation (BLUE Map) and business-as-usual (Baseline) scenarios of the International Energy Agency up to 2050. We use a vintage stock model to conduct an LCA of newly installed capacity year-by-year for each region, thus accounting for changes in the energy mix used to manufacture future power plants. Under the Baseline scenario, emissions of air and water pollutants more than double whereas the low-carbon technologies introduced in the BLUE Map scenario allow a doubling of electricity supply while stabilizing or even reducing pollution. Material requirements per unit generation for low-carbon technologies can be higher than for conventional fossil generation: 11-40 times more copper for photovoltaic systems and 6-14 times more iron for wind power plants. However, only two years of current global copper and one year of iron production will suffice to build a low-carbon energy system capable of supplying the world’s electricity needs in 2050.

Concepts: Oxygen, Carbon dioxide, Iron, Renewable energy, Coal, Wind power, Electricity generation, Low-carbon economy

71

The European high Alps are internationally renowned for their dairy produce, which are of huge cultural and economic significance to the region. Although the recent history of alpine dairying has been well studied, virtually nothing is known regarding the origins of this practice. This is due to poor preservation of high altitude archaeological sites and the ephemeral nature of transhumance economic practices. Archaeologists have suggested that stone structures that appear around 3,000 years ago are associated with more intense seasonal occupation of the high Alps and perhaps the establishment of new economic strategies. Here, we report on organic residue analysis of small fragments of pottery sherds that are occasionally preserved both at these sites and earlier prehistoric rock-shelters. Based mainly on isotopic criteria, dairy lipids could only be identified on ceramics from the stone structures, which date to the Iron Age (ca. 3,000-2,500 BP), providing the earliest evidence of this practice in the high Alps. Dairy production in such a marginal environment implies a high degree of risk even by today’s standards. We postulate that this practice was driven by population increase and climate deterioration that put pressure on lowland agropastoral systems and the establishment of more extensive trade networks, leading to greater demand for highly nutritious and transportable dairy products.

Concepts: Iron, Milk, Dairy, Organic chemistry, Pottery, Archaeology, Prehistory, Alps

64

Tea interferes with iron absorption and can lead to iron deficiency anemia when consumed in large quantities. The rechallenge effect of green tea on anemia in a middle-aged man emphasizes the potential causal role of this beverage. Lifestyle and dietary habits are important diagnostic considerations in diseases of this type.

Concepts: Hemoglobin, Death, Iron, Iron deficiency anemia, Transferrin, Human iron metabolism

61

The Eridania region in the southern highlands of Mars once contained a vast inland sea with a volume of water greater than that of all other Martian lakes combined. Here we show that the most ancient materials within Eridania are thick (>400 m), massive (not bedded), mottled deposits containing saponite, talc-saponite, Fe-rich mica (for example, glauconite-nontronite), Fe- and Mg-serpentine, Mg-Fe-Ca-carbonate and probable Fe-sulphide that likely formed in a deep water (500-1,500 m) hydrothermal setting. The Eridania basin occurs within some of the most ancient terrain on Mars where striking evidence for remnant magnetism might suggest an early phase of crustal spreading. The relatively well-preserved seafloor hydrothermal deposits in Eridania are contemporaneous with the earliest evidence for life on Earth in potentially similar environments 3.8 billion years ago, and might provide an invaluable window into the environmental conditions of early Earth.

Concepts: Oxygen, Iron, Life, Environment, Mars, Seafloor spreading

61

Abnormal accumulation of brain metals is a key feature of Alzheimer’s disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), nano-beam electron diffraction, electron holography and analytical spectroscopy techniques (EDX and EELS), we demonstrate that Fe in APC is present as iron oxide (Fe3O4) magnetite nanoparticles. Here we show that Fe was accumulated primarily as nanostructured particles within APC, whereas Cu and Zn were distributed through the amyloid fibers. Remarkably, these highly organized crystalline magnetite nanostructures directly bound into fibrillar Aβ showed characteristic superparamagnetic responses with saturated magnetization with circular contours, as observed for the first time by off-axis electron holography of nanometer scale particles.

Concepts: Electron, Iron, Magnetism, Aluminium, Transmission electron microscopy, Iron ore, Magnetite, Hematite