Electrical Detection and Magnetic Imaging of Stabilized Magnetic Skyrmions in Fe1−xCoxGe (x < 0.1) Microplates

Magnetic skyrmions are topologically protected spin textures that are being investigated for their potential use in next generation magnetic storage devices. Here, magnetic skyrmions and other magnetic phases in Fe_1?xCo_xGe (x < 0.1) microplates (MPLs) newly synthesized via chemical vapor deposition are studied using both magnetic imaging and transport measurements. Lorentz transmission electron microscopy reveals a stabilized magnetic skyrmion phase near room temperature (≈280 K) and a quenched metastable skyrmion lattice via field cooling. Magnetoresistance (MR) measurements in three different configurations reveal a unique anomalous MR signal at temperatures below 200 K and two distinct field dependent magnetic transitions. The topological Hall effect (THE), known as the electronic signature of magnetic skyrmion phase, is detected for the first time in a Fe_1?xCo_xGe nanostructure, with a large and positive peak THE resistivity of ≈32 nΩ cm at 260 K. This large magnitude is attributed to both nanostructuring and decreased carrier concentrations due to Co alloying of the Fe_1?xCo_xGe MPL. A consistent magnetic phase diagram summarized from both the magnetic imaging and transport measurements shows that the magnetic skyrmions are stabilized in Fe_1?xCo_xGe MPLs compared to bulk materials. This study lays the foundation for future skyrmion‐based nanodevices in information storage technologies.     

Recent Advances in Sensing Applications of Graphene Assemblies and Their Composites

Development of next‐generation sensor devices is gaining tremendous attention in both academia and industry because of their broad applications in manufacturing processes, food and environment control, medicine, disease diagnostics, security and defense, aerospace, and so forth. Current challenges include the development of low‐cost, ultrahigh, and user‐friendly sensors, which have high selectivity, fast response and recovery times, and small dimensions. The critical demands of these new sensors are typically associated with advanced nanoscale sensing materials. Among them, graphene and its derivatives have demonstrated the ideal properties to overcome these challenges and have merged as one of the most popular sensing platforms for diverse applications. A broad range of graphene assemblies with different architectures, morphologies, and scales (from nano‐, micro‐, to macrosize) have been explored in recent years for designing new high‐performing sensing devices. Herein, this study presents and discusses recent advances in synthesis strategies of assembled graphene‐based superstructures of 1D, 2D, and 3D macroscopic shapes in the forms of fibers, thin films, and foams/aerogels. The fabricated state‐of‐the‐art applications of these materials in gas and vapor, biomedical, piezoresistive strain and pressure, heavy metal ion, and temperature sensors are also systematically reviewed and discussed, and their sensing performance is compared.     

Crops that feed the world 10. Past successes and future challenges to the role played by wheat in global food security

Wheat is fundamental to human civilization and has played an outstanding role in feeding a hungry world and improving global food security. The crop contributes about 20 % of the total dietary calories and proteins worldwide. Food demand in the developing regions is growing by 1 % annually and varies from 170 kg in Central Asia to 27 kg in East and South Africa. The developing regions (including China and Central Asia) account for roughly 53 % of the total harvested area and 50 % of the production. Unprecedented productivity growth from the Green Revolution (GR) since the 1960s dramatically transformed world wheat production, benefitting both producers and consumers through low production costs and low food prices. Modern wheat varieties were adopted more rapidly than any other technological innovation in the history of agriculture, recently reaching about 90 % of the area in developing regions. One of the key challenges today is to replace these varieties with new ones for better sustainability. While the GR “spared” essential ecosystems from conversion to agriculture, it also generated its own environmental problems. Also productivity increase is now slow or static. Achieving the productivity gains needed to ensure food security will therefore require more than a repeat performance of the GR of the past. Future demand will need to be achieved through sustainable intensification that combines better crop resistance to diseases and pests, adaptation to warmer climates, and reduced use of water, fertilizer, labor and fuel. Meeting these challenges will require concerted efforts in research and innovation to develop and deploy viable solutions. Substantive investment will be required to realize sustainable productivity growth through better technologies and policy and institutional innovations that facilitate farmer adoption and adaptation. The enduring lessons from the GR and the recent efforts for sustainable intensification of cereal systems in South Asia and other regions provide useful insights for the future.     

Economic incentives to use fertilizer on maize under differing agro-ecological conditions in Burkina Faso

Increasing agricultural productivity while protecting natural resources depends on proper understanding of farmers’ incentives to use intensification strategies, including fertilizer. Using a large-scale household dataset collected in rural Burkina Faso, we examined how the response of maize yield to fertilizer, and thus the economic incentives for its use, varied according to agro-ecological conditions. We employed a Control Function Approach with Correlated Random Effects in order to test and control for endogeneity of fertilizer use, measuring agro-ecological conditions at several scales. We investigated the profitability of fertilizer use with value-cost ratios. We found that productivity and marginal effects of fertilizer differ significantly according to agro-ecological conditions. Micro-variation appeared to be more critical than the definition of agro-ecological zone. Burkinabe soils are severely degraded and would benefit from greater application of fertilizer. However, at full market prices, fertilizer use was unprofitable. Though it was profitable with subsidized prices, transaction costs diminish the benefits of the subsidy. Profitability of fertilizer use with maize varied across agro-ecological conditions, even for field plots located in the same agro-ecological zone. Our results confirm that policy makers need to be cautious when generalizing across regions or drawing policy recommendations from a single agro-ecological zone because crop responses and economic incentives vary widely.     

Studying photography in Memphis

Abstract

While Memphis, Tennessee, is famous for barbecues, Elvis, blues, and a forty-storey pyramid, its photographic opportunities are less well publicized. Yet Memphis boasts three photographic historians, a university photography programme with graduate and undergraduate degrees, and fascinating photography collections.     

Application of microcalorimetry to the study of interactions in coating formulations

Water-based coating formulations contain many components, such as latex binder, pigment, dispersant, thickener, and surfactant. Complex interactions between these components affect properties of the coating in both the wet and dried states. For example, rheology of the paint is dependent on the interactions of components in the formulation. Pigment interaction can affect the degree of dispersion and, therefore, have ramifications on end use properties such as hiding and tint strength of the paint film. Isothermal titration calorimetry has been used to determine the enthalpy of interaction of the coating components. Representative examples will be given to demonstrate structure–property relationships that correlate the interactions of latex, pigment, surfactant, dispersant, and thickener with paint viscosity as well as end use performance parameters such as adhesion and tint strength.     

Chronic toxicological evaluation of dietary NovaSil Clay in Sprague-Dawley rats

NovaSil (NS) clay, a common anti-caking agent in animal feeds, has been shown to sorb aflatoxins in the GI tract and diminish their bioavailability and adverse effects in short-term animal studies. Based on this evidence, it is hypothesized that clay-based enterosorption of aflatoxins may be a useful strategy for the prevention of aflatoxicosis in human populations. However, the potential toxicity of long-term dietary exposure to NS has not been determined. In this research, 5-6-week-old male and female Sprague-Dawley rats were fed rations containing 0, 0.25, 0.5, 1.0, or 2.0% (w/w) levels of NS for 28 weeks. Analysis of the NS showed negligible levels of dioxin and furan contaminants. Total feed consumption, cumulative feed consumption, body weight, total body weight gain, feed conversion efficiency, cumulative feed conversion efficiency, and relative organ weights were unaffected in either sex at the doses tested. No NS-dependent differences in relative organ weights or gross or histopathological changes were observed. Analysis of hematological parameters, clinical chemistry, and selected vitamin and mineral levels revealed isolated significant differences between some treatments and control groups (mean corpuscular hemoglobin, serum Ca, serum vitamin A, and serum Fe). However, the differences observed in each case were not dose-dependent. These results suggest that dietary inclusion of NS at levels as high as 2.0% (w/w) does not result in overt toxicity. These findings (as well as others) support the use of NS clay for dietary intervention studies in human populations at high risk for aflatoxicosis.     

新粘接系统改善触摸屏组装和可靠性

触摸屏在银行ATM、售货亭、销售点以及机场自动售票机等应用中获得了广泛的应用,技术发展非常迅速。触摸屏的结构以及组件也发生了变化,这需要新的透明性更好且没有污染和腐蚀性的组件。电友好的分隔颗粒层间粘接带(electronically　clean　spacer　tapes)、导电粘接带(electrically　conductive　bonding　tapes)以及化学惰性透明粘接剂(chemicallyinert　optically　clear　adhesives)等产品的出现使得触摸屏OEM 厂商可以开发出更为可靠的产品。 触摸屏市场及其技术 目前,特别是随着PDA的普及,触摸屏成为发展最快的输入设备之一。表…     

In vitro microbial metabolism of fumonisin B1

There is a lack of information on the effect of swine caecal microbiota on fumonisin metabolism. In this in vitro study, the biotransformation of fumonisin B₁ (FB₁) by the gut microbiota of adult, healthy pigs was examined. Suspensions of caecal contents and McDougall buffer solution were incubated anaerobically with pure FB₁ for 0, 12, 24, 48 and 72 h. After 48 h, the conversion of FB₁ to partially hydrolysed FB₁ (46%) was nearly equal to the percentage ratio of FB₁, while by 72 h it was 49%. In vitro, the conversion of fumonisin B₁ to aminopentol was less than 1%. The results show that the caecal microbiota are capable of transforming fumonisin B₁ to the above metabolites. Further studies on FB₁ metabolism in the small intestine are clearly justified.