An optimum heating program for fabricating MTG Bi1.6Pb0.4Sr2Ca2Cu3Oy superconductors

Following our recent report on the successful fabrication of “stationary” MTG Bi1.6Pb0.4Sr2Ca2Cu3Oy pellets in a simple tube furnace, we have tried many heating programs with various “crystal growth starting temperatures”, Ts, and sintering temperatures, Te; the samples are sintered for 20–40 h before quenching in air. It is found that Ts-Te should be rather narrow to produce good MTG samples, and the typical value of Jc is enhanced from 100 A cm22 (for a polycrystalline sample) to about 3 3 103 A cm22 for our good ones. SEM and TEM results indicate that the samples are full of packs which contain highly oriented mica-like layers.published_or_final_versio

Chemical composition and toxic activity of essential oil of Caryopteris incana against Sitophilus zeamais

During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Caryopteris incana aerial parts was found to possess strong insecticidal activities against the maize weevil, Sitophilus zeamais. A total of 37 components of the essential oil were identified by GC and GC/MS. Estragole (24.8%) and linalool (14.0%) are the two main components of the essential oil followed by 1,8-cineol (5.2%) and δ-guaiene (4.1%). The essential oil possesses strong fumigant toxicity against S. zeamais adults with an LC50 value of 10.05 mg/L air. The essential oil of C. incana also showed contact toxicity against S. zeamais adults with an LD50 value of 122.65 μg/adult. The essential oil C. incana may have potential to be developed as a new natural fumigant/insecticide for the control of stored product insects.Key words: Caryopteris incana, Sitophilus zeamais, fumigant, contact toxicity, essential oil composition, estragole, linalool

Field-testing of the revised, draft South African Paediatric Food-Based Dietary Guidelines amongst mothers/caregivers of children aged 0–12 months in the Breede Valley sub-district, Western Cape province, South Africa

Objectives: To assess the appropriateness and understanding of the revised, draft South African Paediatric Food-Based Dietary Guidelines (SA-PFBDGs) amongst mothers/caregivers of children aged 0–12 months. Exposure to guidelines with similar messages, barriers and enablers to following of the guidelines were also assessed. Design: Qualitative data were collected from 14 focus-group discussions (FGDs), conducted in isiXhosa (n = 5), English (n = 4) and Afrikaans (n = 5), totalling 73 mother/caregiver participants. Setting: Worcester, Breede Valley sub-district, Western Cape province. Subjects: The study population included mothers/caregivers who were older than 18 years. Results: The majority of participants had previous exposure to variations of messages similar to the revised, draft SA-PFBDGs. Health platforms and practitioners (community health centres, antenatal classes, nurses, doctors) and social networks and platforms (family, magazines, radio) were mentioned as primary sources of information. Barriers to following the messages included: inconsistent messages (mainly communicated by healthcare workers), contrasting beliefs and cultural/family practices, limited physical and financial access to resources, poor social support structures and the psycho-social and physical demands of raising a child. Conclusion: The revised, draft SA-PFBDGs for the age range 0–12 months have been field-tested in English, Afrikaans and isiXhosa. The messages in some of the revised, draft SA-PFBDGs were not understood by the participants, indicating that a degree of rewording should be considered to facilitate understanding of the guidelines by the public. The National Department of Health should consider the findings of this study, and use these standardised message/s to optimise infant and young child feeding

Ageing memory and glassiness of a driven vortex system

Many systems in nature, glasses, interfaces and fractures being some examples, cannot equilibrate with their environment, which gives rise to novel and surprising behaviour such as memory effects, ageing and nonlinear dynamics. Unlike their equilibrated counterparts, the dynamics of out-of- equilibrium systems is generally too complex to be captured by simple macroscopic laws. Here we investigate a system that straddles the boundary between glass and crystal: a Bragg glass formed by vortices in a superconductor. We find that the response to an applied force evolves according to a stretched exponential, with the exponent reflecting the deviation from equilibrium. After the force is removed, the system ages with time and its subsequent response time scales linearly with its age (simple ageing), meaning that older systems are slower than younger ones. We show that simple ageing can occur naturally in the presence of sufficient quenched disorder. Moreover, the hierarchical distribution of timescales, arising when chunks of loose vortices cannot move before trapped ones become dislodged, leads to a stretched-exponential response.Comment: 16 pages, 5 figure

The influence of initial xylose concentration, agitation, and aeration on ethanol production by Pichia stipitis from rice straw hemicellulosic hydrolysate

Rice straw hemicellulosic hydrolysate was used as fermentation medium for ethanol production by Pichia stipitis NRRL Y-7124. Shaking bath experiments were initially performed aiming to establish the best initial xylose concentration to be used in this bioconversion process. In the sequence, assays were carried out under different agitation (100 to 200 rpm) and aeration (V flask/V medium ratio varying from 2.5 to 5.0) conditions, and the influence of these variables on the fermentative parameters values (ethanol yield factor, Y P/S; cell yield factor, Y X/S; and ethanol volumetric productivity, Q P) was investigated through a 22 full-factorial design. Initial xylose concentration of about 50 g/l was the most suitable for the development of this process, since the yeast was able to convert substrate in product with high efficiency. The factorial design assays showed a strong influence of both process variables in all the evaluated responses. The agitation and aeration increase caused a deviation in the yeast metabolism from ethanol to biomass production. The best results (Y P/S = 0.37 g/g and Q P = 0.39 g/l.h) were found when the lowest aeration (2.5 V flask/V medium ratio) and highest agitation (200 rpm) levels were employed. Under this condition, a process efficiency of 72.5% was achieved. These results demonstrated that the establishment of adequate conditions of aeration is of great relevance to improve the ethanol production from xylose by Pichia stipitis, using rice straw hemicellulosic hydrolysate as fermentation medium.The financial support from Fapesp (Brazil) is gratefully acknowledged

Segmentation of Fluorescence Microscopy Cell Images Using Unsupervised Mining

The accurate measurement of cell and nuclei contours are critical for the sensitive and specific detection of changes in normal cells in several medical informatics disciplines. Within microscopy, this task is facilitated using fluorescence cell stains, and segmentation is often the first step in such approaches. Due to the complex nature of cell issues and problems inherent to microscopy, unsupervised mining approaches of clustering can be incorporated in the segmentation of cells. In this study, we have developed and evaluated the performance of multiple unsupervised data mining techniques in cell image segmentation. We adapt four distinctive, yet complementary, methods for unsupervised learning, including those based on k-means clustering, EM, Otsu’s threshold, and GMAC. Validation measures are defined, and the performance of the techniques is evaluated both quantitatively and qualitatively using synthetic and recently published real data. Experimental results demonstrate that k-means, Otsu’s threshold, and GMAC perform similarly, and have more precise segmentation results than EM. We report that EM has higher recall values and lower precision results from under-segmentation due to its Gaussian model assumption. We also demonstrate that these methods need spatial information to segment complex real cell images with a high degree of efficacy, as expected in many medical informatics applications

Electronic and Geometric Structures of Rechargeable Lithium Manganese Sulfate Li2Mn(SO4)2 Cathode

Here, we report the use of Li2Mn(SO4)2 as a potential energy storage material and describe its route of synthesis and structural characterization over one electrochemical cycle. Li2Mn(SO4)2 is synthesized by ball milling of MnSO4·H2O and Li2SO4·H2O and characterized using a suite of techniques, in particular, ex situ X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy on the Mn and S K-edges to investigate the electronic and local geometry around the absorbing atoms. The prepared Li2Mn-(SO4)2 electrodes undergo electrochemical cycles to different potential points on the charge−discharge curve and are then extracted from the cells at these points for ex situ structural analysis. Analysis of X-ray absorption spectroscopy (both near and fine structure part of the data) data suggests that there are minimal changes to the oxidation state of Mn and S ions during charge−discharge cycles. However, X-ray photoelectron spectroscopy analysis suggests that there are changes in the oxidation state of Mn, which appears to be different from the conclusion drawn from X-ray absorption spectroscopy. This difference in results during cycling can thus be attributed to electrochemical reactions being dominant at the surface of the Li2Mn(SO4)2 particles rather than in the bulk

Plant-RRBS, a bisulfite and next-generation sequencing-based methylome profiling method enriching for coverage of cytosine positions

Background: Cytosine methylation in plant genomes is important for the regulation of gene transcription and transposon activity. Genome-wide methylomes are studied upon mutation of the DNA methyltransferases, adaptation to environmental stresses or during development. However, from basic biology to breeding programs, there is a need to monitor multiple samples to determine transgenerational methylation inheritance or differential cytosine methylation. Methylome data obtained by sodium hydrogen sulfite (bisulfite)-conversion and next-generation sequencing (NGS) provide genome- wide information on cytosine methylation. However, a profiling method that detects cytosine methylation state dispersed over the genome would allow high-throughput analysis of multiple plant samples with distinct epigenetic signatures. We use specific restriction endonucleases to enrich for cytosine coverage in a bisulfite and NGS-based profiling method, which was compared to whole-genome bisulfite sequencing of the same plant material. Methods: We established an effective methylome profiling method in plants, termed plant-reduced representation bisulfite sequencing (plant-RRBS), using optimized double restriction endonuclease digestion, fragment end repair, adapter ligation, followed by bisulfite conversion, PCR amplification and NGS. We report a performant laboratory protocol and a straightforward bioinformatics data analysis pipeline for plant-RRBS, applicable for any reference-sequenced plant species. Results: As a proof of concept, methylome profiling was performed using an Oryza sativa ssp. indica pure breeding line and a derived epigenetically altered line (epiline). Plant-RRBS detects methylation levels at tens of millions of cytosine positions deduced from bisulfite conversion in multiple samples. To evaluate the method, the coverage of cytosine positions, the intra-line similarity and the differential cytosine methylation levels between the pure breeding line and the epiline were determined. Plant-RRBS reproducibly covers commonly up to one fourth of the cytosine positions in the rice genome when using MspI-DpnII within a group of five biological replicates of a line. The method predominantly detects cytosine methylation in putative promoter regions and not-annotated regions in rice. Conclusions: Plant-RRBS offers high-throughput and broad, genome- dispersed methylation detection by effective read number generation obtained from reproducibly covered genome fractions using optimized endonuclease combinations, facilitating comparative analyses of multi-sample studies for cytosine methylation and transgenerational stability in experimental material and plant breeding populations

Physical and Electrical Performance of Vapor–Solid Grown ZnO Straight Nanowires

Physical and electrical properties of wurtzitic ZnO straight nanowires grown via a vapor–solid mechanism were investigated. Raman spectrum shows four first-order phonon frequencies and a second-order Raman frequency of the ZnO nanowires. Electrical and photoconductive performance of individual ZnO straight nanowire devices was studied. The results indicate that the nanowires reported here are n-type semi-conductors and UV light sensitive, and a desirable candidate for fabricating UV light nanosensors and other applications