Transparent ferromagnetic and semiconducting behavior in Fe-Dy-Tb based amorphous oxide films

We report a class of amorphous thin film material comprising of transition (Fe) and Lanthanide metals (Dy and Tb) that show unique combination of functional properties. Films were deposited with different atomic weight ratio (R) of Fe to Lanthanide (Dy + Tb) using electron beam co-evaporation at room temperature. The films were found to be amorphous, with grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy studies indicating that the films were largely oxidized with a majority of the metal being in higher oxidation states. Films with R = 0.6 were semiconducting with visible light transmission due to a direct optical band-gap (2.49 eV), had low resistivity and sheet resistance (7.15 × 10−4 Ω-cm and ~200 Ω/sq respectively), and showed room temperature ferromagnetism. A metal to semiconductor transition with composition (for R \u3c 11.9) also correlated well with the absence of any metallic Fe0oxidation state in the R = 0.6 case as well as a significantly higher fraction of oxidized Dy. The combination of amorphous microstructure and room temperature electronic and magnetic properties could lead to the use of the material in multiple applications, including as a transparent conductor, active material in thin film transistors for display devices, and in spin-dependent electronics

Highly efficient transfection of human induced pluripotent stem cells using magnetic nanoparticles.

PurposeThe delivery of transgenes into human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs) represents an important tool in cardiac regeneration with potential for clinical applications. Gene transfection is more difficult, however, for hiPSCs and hiPSC-CMs than for somatic cells. Despite improvements in transfection and transduction, the efficiency, cytotoxicity, safety, and cost of these methods remain unsatisfactory. The objective of this study is to examine gene transfection in hiPSCs and hiPSC-CMs using magnetic nanoparticles (NPs).MethodsMagnetic NPs are unique transfection reagents that form complexes with nucleic acids by ionic interaction. The particles, loaded with nucleic acids, can be guided by a magnetic field to allow their concentration onto the surface of the cell membrane. Subsequent uptake of the loaded particles by the cells allows for high efficiency transfection of the cells with nucleic acids. We developed a new method using magnetic NPs to transfect hiPSCs and hiPSC-CMs. HiPSCs and hiPSC-CMs were cultured and analyzed using confocal microscopy, flow cytometry, and patch clamp recordings to quantify the transfection efficiency and cellular function.ResultsWe compared the transfection efficiency of hiPSCs with that of human embryonic kidney (HEK 293) cells. We observed that the average efficiency in hiPSCs was 43%±2% compared to 62%±4% in HEK 293 cells. Further analysis of the transfected hiPSCs showed that the differentiation of hiPSCs to hiPSC-CMs was not altered by NPs. Finally, robust transfection of hiPSC-CMs with an efficiency of 18%±2% was obtained.ConclusionThe difficult-to-transfect hiPSCs and hiPSC-CMs were efficiently transfected using magnetic NPs. Our study offers a novel approach for transfection of hiPSCs and hiPSC-CMs without the need for viral vector generation

Melatonin application suppresses oxidative stress and maintains fruit quality of cold stored ‘Esperanza’ raspberries by regulating antioxidant system

Raspberries are highly perishable and have a short storage life. To extend its storage life, we evaluated the impact of preharvest melatonin (MEL) application (0, 50, 100, 200 mol L−1), three days before harvest, on the activities of oxidative and antioxidative enzymes and quality attributes in ‘Esperanza’ raspberries up to 10 d cold storage. The 200 mol L−1 MEL-treated raspberries exhibited a significant reduction in disease incidence while maintaining higher marketable fruit and activities of superoxide dismutase, glutathione reductase, dehydroascorbate reductase, monodehydroascorbate reductase, ascorbate peroxidase and catalase as compared to control. Additionally, it reduced activities of polyphenol oxidase, peroxidase and lipoxygenase enzymes and increased flavonoids and ascorbic acid levels. However, preharvest spray of 100 mol L−1 MEL mitigated fruit weight loss and maintained higher anthocyanins, and glutathione than control. In conclusion, MEL application (100–200 mol L−1), three days before harvest, supressed oxidative stress by maintaining higher activities of antioxidant enzymes in raspberries during 10 d of cold storage

Analysis of thermal-hydraulic transients for the Miniature Neutron Source Reactor (MNSR) in Ghana

Abstract: A mathematical model is presented that permits to simulate the effect of the cooling coils of the pool upper section on the reactor thermal-hydraulic behaviour of Ghana research reactor-1. The model is based on a lumped parameter description solved numerically using Matlab/Simulink tool which is a commercial software package with the capability of modelling dynamical and control systems. The model incorporates fuel grids and cooling coil models as well as radiating energy from the clad. In this model, the reactor tank and the pool is divided into three sections. The model predictions are qualified by comparing the results with experimental data. The effect of cooling the upper section of the pool on reactor thermal-hydraulic parameters using the cooling coil is presented and discussed. It was observed that all maximum values of the reactor thermalhydraulic parameters decrease when the cooling coil power is increased. Good agreement is found between the model predictions and the experimental results

Use of rainfall indices to analyze the effects of phosphate rocks on millet in the Sahel

Two critical factors that explain low crop productivity in the Sahelian agro-ecozone are inadequate moisture and poor soils, particularly phosphorus (P) deficiency. The purpose of this long-term study was to explore the use of both local phosphate rock (PR) and inorganic P on yields and risk of millet returns under the uncertain rainfall regimes in the Sahel. Using the Standardized Precipitation Index (SPI) and Percent Confidence Limits (PCL) of the mean rainfall, the 10-year experimental period was grouped into rainfall classes. Results showed that the inorganic P fertilizers, that is, single superphosphate and triple superphosphate (SSP+N and TSP) gave the highest average yields. Also, millet yield increased with increasing P rates. However, typical farmers in the Sahel barely use P rates above 20 kg ha-1 in view of the high cost of imported fertilizers. A low application rate of the local PR, 10 kg P ha-1, increased millet yield between 44 and 67%. Stability analysis using yields from 15 farmers’ fields indicated that the traditional method of growing millet was the least stable (s.e. = 225) and had the lowest yield (314 kg ha-1). Generally, millet responded to P better when the preseason (May-June) were wet than dry, except where the non-acidulated PR (PRA) was applied every year (R2=0.99, P < 0.01) for both dry and wet preseasons. Risk analysis showed that acidulated PR regardless of rates gave the highest millet returns over variable cost of P fertilizer. The study recommends the promotion PR in order to guarantee stable yields and income for small farmers in the Sahel

Trend and stability analyses of millet yields treated with fertilizer and crop residues in the Sahel

Pearl millet (Penisetum glaucum (L.) R.Br.) is a major food crop grown on impoverished sandy soils in the Sahel. A 9-year long-term study was undertaken in the Sahel to test the hypothesis that integrated use of millet crop residues retained on farm fields after harvest and mineral fertilizers results in greater and more sustainable yields and conserve soil fertility better than either the use of residue or fertilizer alone. The four treatments compared were: (1) control (crop residue removed and no fertilizer applied), (2) crop residue alone, (3) 30 kg N+13 kg P ha-1 (fertilizer) alone and (4) crop residue+fertilizer. Use of crop residue+fertilizer increased grain yield fourfold over the control; use of fertilizer doubled millet yield relative to the control and crop residues resulted in 1.2 times more yield than the control. Crop residues significantly improved nutrient-use efficiency of the applied fertilizer. Sustainability yield index (SYI), a measure of an upward trend in yield over time, was greatest in crop residue+fertilizer plots as are soil organic carbon, available P and pH. Stability analysis indicated that crop residue+fertilizer treatment gave in greater yields and returns over fertilizer cost in the various seasons than either crop residue or fertilizer

Towards a Framework for Understanding Ethnic Consumers' Acculturation Strategies in a Multicultural Environment: A Food Consumption Perspective

© Bidit Lal Dey, Sharifah Alwi, Fred Yamoah, Stephanie Agyepongmaa Agyepong, Hatice Kizgin andMeera Sarma. Purpose – While it is essential to further research the growing diversity in Western metropolitan cities, little is currently known about how the members of various ethnic communities acculturate to multicultural societies. The purpose of this paper is to explore immigrants’ cosmopolitanism and acculturation strategies through an analysis of the food consumption behaviour of ethnic consumers in multicultural London. Design/Methodology/Approach – The study was set within the socio-cultural context of London. A number of qualitative methods such as in-depth interviews, observation and photographs were used to assess consumers’ acculturation strategies in a multicultural environment and how that is influenced by consumer cosmopolitanism. Findings – Ethnic consumers’ food consumption behaviour reflects their acculturation strategies, which can be classified into four groups: rebellion, rarefaction, resonance and refrainment. This classification demonstrates ethnic consumers’ multi-directional acculturation strategies, which are also determined by their level of cosmopolitanism. Research implications/limitations – The taxonomy presented in this paper advances current acculturation scholarship by suggesting a multi-directional model for acculturation strategies as opposed to the existing uni-directional and bi-directional perspectives and explicates the role of consumer cosmopolitanism in consumer acculturation. The paper did not engage host communities and there is hence a need for future research on how and to what extent host communities are acculturated to the multicultural environment. Practical implications – The findings have direct implications for the choice of standardization versus adaptation as a marketing strategy within multicultural cities. Whilst the rebellion group are more likely to respond to standardization, increasing adaptation of goods and service can ideally target members of the resistance and resonance groups and more fusion products should be exclusively earmarked for the resonance group. Originality/Value – The paper makes original contribution by introducing a multi-directional perspective to acculturation by delineating four-group taxonomy (rebellion, rarefaction, resonance and refrainment). This paper also presents a dynamic model that captures how consumer cosmopolitanism impinges upon the process and outcome of multi-directional acculturation strategies

Simulated weather variables effects on millet fertilized with phosphate rock in the Sahel

The Sudano–Sahelian agroecological zone is characterized by low and variable rainfall regimes and P deficiency. The present study complements previous research efforts and the objective was (i) to use the Newhall Simulation Model (NSM) to characterize three ICRISAT research sites, and (ii) to use output of NSM to develop an empirical model to guide efficient use of rainfall and fertilizers. The results show that length of the periods that rainfall exceeded evapotranspiration was larger in Bengou than in Gobery and Sadoré. Total positive moisture balance during the three growing seasons was 85.7 mm at Bengou and 19.7 mm at Sadoré. The model explained 52% of the variability in millet yields based on curvilinear response to P fertilizer, standardized May–June (Rmj) rainfall, and the number of wet days in the year (BW3). Yields appear more sensitive to BW3 than to Rmj. Their respective elasticity coefficients (E c ) were 0.62 and 0.09. Assessment of the model using R2=0.76 and the D-index = 0.85 showed reasonable agreement between model estimation and actual field yields. The study demonstrates the application of simulation models as a cost-effective means in terms of time and funds to agronomic researc

Enhancing life cycle product design decision-making processes: insights from normal accident theory and satisficing framework

Life Cycle Assessment (LCA), a computational tool used in sustainable product design decision making, faces challenges in the interpretation phase, where conclusions are drawn for improvement recommendations. This necessitate the need to incorporate into LCA management-relevant theoretical underpinnings to strengthen decision-making processes. Comparative LCA case studies of lead-based piezoelectric material (lead zirconate titanate – PZT) and lead-free alternatives (potassium sodium niobate – KNN, sodium bismuth titanate – NBT), was employed to demonstrate how two theoretical lenses, namely Normal Accident Theory (NAT) and Satisficing Framework, are used inductively to enhance decision making regarding unintended consequences in the value chain revealed by LCA outputs. The environmental analysis reveals NAT attributes of interactive complexity and tight coupling in piezoelectric materials, based on systems’ predictability, observability, and applicability, leading to the introduction of Environmental Impact Accident (EIA) as a new concept. EIA facilitates early assessment of the associated complexities influencing the sustainability credentials of piezoelectric materials, informing mitigation strategies. However, a conundrum is created when considering multiple objectives that conflict or trade-off between alternative piezoelectric materials with different environmental and health impacts across the value chain but was resolved using the Satisficing Framework. The paper concludes by proposing theoretical and practical policy options for incorporating LCA into product life cycle decision making