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Excess unabsorbed iron in the gastrointestinal tract may select for enteric pathogens and increase the incidence and severity of infectious disease. Aspergillus oryzae (Ao) is a filamentous fungus that has the ability to accumulate and store large amounts of iron, and when used as a supplement or fortificant, has similar absorption to ferrous sulphate (FeSO4) in humans. The objective of this study was to determine the effect of iron-enriched Ao (Ao iron) compared with FeSO4 on iron accumulation, growth and motility of the Gram-negative enteric pathogen, S. Typhimurium. S. Typhimurium was cultured in media containing no added iron or 1 μM elemental iron as either Ao iron or FeSO4. S. Typhimurium cultured with FeSO4 accumulated more iron than those cultured with Ao iron. Genes regulated by the iron-activated transcriptional repressor, Fur, did not differ between control and Ao iron, but decreased in S. Typhimurium cultured with FeSO4 compared with both groups. Growth of S. Typhimurium was greater when cultured with FeSO4 compared with Ao iron and control. S. Typhimurium swam faster, had greater acceleration and travelled further when cultured with FeSO4 compared with Ao iron and control; swim speed, acceleration and distance travelled did not differ between Ao iron and control. These findings provide evidence that Ao iron reduces the virulence of a common enteric pathogen in vitro. Further research is required to determine whether iron-enriched Ao is a suitable iron supplement to improve iron delivery in areas with a high infection burden.
Yarkoni's analysis clearly articulates a number of concerns limiting the generalizability and explanatory power of psychological findings, many of which are compounded in infancy research. ManyBabies addresses these concerns via a radically collaborative, large-scale and open approach to research that is grounded in theory-building, committed to diversification, and focused on understanding sources of variation.
Vertical hetero-structures made from stacked monolayers of transition metal dichalcogenides (TMDC) are promising candidates for next-generation optoelectronic and thermoelectric devices. Identification of optimal layered materials for these applications requires the calculation of several physical properties, including electronic band structure and thermal transport coefficients. However, exhaustive screening of the material structure space using ab initio calculations is currently outside the bounds of existing computational resources. Furthermore, the functional form of how the physical properties relate to the structure is unknown, making gradient-based optimization unsuitable. Here, we present a model based on the Bayesian optimization technique to optimize layered TMDC hetero-structures, performing a minimal number of structure calculations. We use the electronic band gap and thermoelectric figure of merit as representative physical properties for optimization. The electronic band structure calculations were performed within the Materials Project framework, while thermoelectric properties were computed with BoltzTraP. With high probability, the Bayesian optimization process is able to discover the optimal hetero-structure after evaluation of only ∼20% of all possible 3-layered structures. In addition, we have used a Gaussian regression model to predict not only the band gap but also the valence band maximum and conduction band minimum energies as a function of the momentum.
Atrazine is the most widely used herbicide in the U.S. and has been detected in surface water and groundwater. Technologies are needed for onsite and in situ remediation of water and soil containing atrazine. We investigated the potential of using fine-grained, zero-valent iron (Fe0) to remove atrazine and promote its degradation in contaminated water and soil. Atrazine loss from aqueous solution increased with increasing Fe0 concentration (w/v). Agitating 20 μg 14C-ring-labeled atrazine L−1 with 10% Fe0 (w/v) removed 92% of the 14C from solution within 48 h. Only about 4% of the 14C lost from solution was extractable from the iron with 3 mM CaCl2 (readily available pool), 81% was extractable with CH3CN (potentially available pool), and 11% was unextractable residues. A companion experiment indicated that most of the 14C extracted from the iron with 3 mM CaCl2 after the 48-h Fe0 treatment was unaltered atrazine, while the CH3CN extract contained approximately 33% atrazine and 48% was unidentified atrazine transformation products. Treating a highly contaminated solution (20 mg atrazine L−1) with 20% Fe0 (w/v) removed 88% of the 14C (added as 14C-ring-labeled atrazine) from solution within 48 h. Deethylatrazine was the main atrazine transformation product detected in solution after treatment, but small amounts of deisopropylatrazine, didealkylatrazine, and hydroxyatrazine were also found. Treating Sharpsburg surface soil containing 1 mg atrazine kg−1 with Fe0 (2%, w/w) increased atrazine mineralization from 4.1 to 11.2% after 120 d. Pyrite (4% FeS2, w/w) also increased atrazine mineralization in surface soil, but was less effective in the presence of NO3− or SO42− (100 mg kg−1 soil). Adding 2% Fe0 (w/w) and 100 mg NO3− kg−1 to contaminated subsurface soil increased atrazine mineralization from 0.4 to 8.2% within 120 d, and unextractable residues increased from 4.6 to 9.8%. These results indicate iron can sorb atrazine and promote its transformation in water and soil.
Phytotoxins from lantana leaves were extracted in aqueous media adjusted to pH 4, 7, or 10. All three leaf extracts showed considerable phytotoxic activity in duckweed growth bioassay. The acidic and the neutral extracts of lantana leaves at 10 g fresh weight/L were more phytotoxic to duckweed growth than the alkaline extract at the same concentration. Phenolic compounds present in lantana leaves were isolated by alkaline hydrolysis of the crude leaf extracts followed by separation of the various components in ether or aqueous media. The fraction containing the phenolics showed considerable phytotoxic activity against duckweed growth. In addition, the fraction containing the nonpolar substances separated from the acidic and the neutral crude extracts also showed significant phytotoxic activity against duckweed growth. No attempt was made to isolate and identify the phytotoxic component from the nonpolar fraction. Characterization of the phenolic fraction by HPLC revealed the presence of at least 14 phenolic compounds. All three leaf extracts contained the same array of phenolic compounds. However, the quantity of phenolic compounds extracted varied with the pH of the extraction medium. The acidic extract contained p-hydroxybenzoic acid (0.09 mM) as the most abundant phenolic compound, whereas the neutral and the basic extracts contained p-coumaric acid (0.11 and 0.26 mM, respectively) as the most abundant phenolic compound. All phenolic compounds, except p-hydroxybenzoic acid, proved phytotoxic to duckweed growth at a concentration of 1 mM or lower. Salicylic acid was the most phytotoxic of the phenolic compounds detected in lantana leaf extracts. The phytotoxicity of lantana leaf extracts is probably partly due to a complex interaction of all phenolic compounds present.
High-resolution (or “cross-correlation”) electron backscatter diffraction analysis (HR-EBSD) utilizes cross-correlation techniques to determine relative orientation and distortion of an experimental electron backscatter diffraction pattern with respect to a reference pattern. The integrity of absolute strain and tetragonality measurements of a standard Si/SiGe material have previously been analyzed using reference patterns produced by kinematical simulation. Although the results were promising, the noise levels were significantly higher for kinematically produced patterns, compared with real patterns taken from the Si region of the sample. This paper applies HR-EBSD techniques to analyze lattice distortion in an Si/SiGe sample, using recently developed dynamically simulated patterns. The results are compared with those from experimental and kinematically simulated patterns. Dynamical patterns provide significantly more precision than kinematical patterns. Dynamical patterns also provide better estimates of tetragonality at low levels of distortion relative to the reference pattern; kinematical patterns can perform better at large values of relative tetragonality due to the ability to rapidly generate patterns relating to a distorted lattice. A library of dynamically generated patterns with different lattice parameters might be used to achieve a similar advantage. The convergence of the cross-correlation approach is also assessed for the different reference pattern types.
High-quality services for people with psychosis are essential. However, in
this debate David Castle questions whether separate early intervention
services are the best option and argues instead for an integrated approach.
Swaran Singh responds, robustly defending the value of early intervention
Risk for depression is expressed across multiple levels of analysis. For example, parental depression and cognitive vulnerability are known markers of depression risk, but no study has examined their interactive effects on children's cortisol reactivity, a likely mediator of early depression risk. We examined relations across these different levels of vulnerability using cross-sectional and longitudinal methods in two community samples of children. Children were assessed for cognitive vulnerability using self-reports (Study 1; n = 244) and tasks tapping memory and attentional bias (Study 2; n = 205), and their parents were assessed for depression history using structured clinical interviews. In both samples, children participated in standardized stress tasks and cortisol reactivity was assessed. Cross-sectionally and longitudinally, parental depression history and child cognitive vulnerability interacted to predict children's cortisol reactivity; associations between parent depression and elevated child cortisol activity were found when children also showed elevated depressotypic attributions as well as attentional and memory biases. Findings indicate that models of children's emerging depression risk may benefit from the examination of the interactive effects of multiple sources of vulnerability across levels of analysis.
The solid state provides a richly varied fabric for intertwining chemical bonding, electronic structure, and magnetism. The discovery of superconductivity in iron pnictides and chalcogenides has revealed new aspects of this interplay, especially involving magnetism and superconductivity. Moreover, it has challenged prior thinking about high-temperature superconductivity by providing a set of materials that differ in many crucial aspects from the previously known cuprate superconductors. Here we review some of what is known about the superconductivity and its interplay with magnetism, chemistry, and electronic structure in Fe-based superconductors.
This chapter describes the development of knowledge concerning microaneurysmal and small hemorrhagic lesions in relation to intracerebral hemorrhage (ICH) and small vessel diseases, which may be relevant in understanding the origin of radiologically defined cerebral microbleeds (CMBs). The hypothesis that has arisen from the work of Jean-Martin Charcot and Charles-Joseph Bouchard is that pathological changes (degenerative or inflammatory, and often associated with arterial hypertension) in small caliber arterioles (up to approximately 300 µm) cause weakening of the wall and microaneurysm formation, which subsequently may rupture to cause ICH. Cerebral microbleeds are particularly common in ICH suggesting that they may provide clues to the underlying cause and could potentially shed light on the role of microaneurysms. Cerebral amyloid angiopathy is now recognized as a common disorder of elderly populations and is characterized by the deposition of amyloid in cerebral cortical and leptomeningeal small vessels.