Correlation between morphology and magnetic properties of electrochemically produced cobalt powder particles

Cobalt 3D powder particles were successfully prepared by galvanostatic electrodeposition. The electrodeposited cobalt powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and SQUID magnetometry. It was shown that the morphology, structure and magnetic properties of cobalt particles were closely associated and could be easily controlled by adjusting the electrodeposition process parameters. The morphology of cobalt powder particles was strongly affected by the hydrogen evolution reaction as a parallel reaction to cobalt electrodeposition. Depending on the applied current density, two types of powder particles were formed: dendrites at lower and spongy-like particles at higher current densities. Morphologies and structures of powder particles were correlated with their magnetic properties, and compared with those of the bulk cobalt. In comparison with the properties of bulk cobalt, the obtained 3D structutes exhibited a decreased saturation magnetization (M-S), but an enhanced coercivity (H-C), which was explained by their peculiar morphology

Characterizing RecA-Independent Induction of Shiga toxin2-Encoding Phages by EDTA Treatment

Background: The bacteriophage life cycle has an important role in Shiga toxin (Stx) expression. The induction of Shiga toxin-encoding phages (Stx phages) increases toxin production as a result of replication of the phage genome, and phage lysis of the host cell also provides a means of Stx toxin to exit the cell. Previous studies suggested that prophage induction might also occur in the absence of SOS response, independently of RecA. Methodology/Principal Findings: The influence of EDTA on RecA-independent Stx2 phage induction was assessed, in laboratory lysogens and in EHEC strains carrying Stx2 phages in their genome, by Real-Time PCR. RecA-independent mechanisms described for phage l induction (RcsA and DsrA) were not involved in Stx2 phage induction. In addition, mutations in the pathway for the stress response of the bacterial envelope to EDTA did not contribute to Stx2 phage induction. The effect of EDTA on Stx phage induction is due to its chelating properties, which was also confirmed by the use of citrate, another chelating agent. Our results indicate that EDTA affects Stx2 phage induction by disruption of the bacterial outer membrane due to chelation of Mg 2+. In all the conditions evaluated, the pH value had a decisive role in Stx2 phage induction. Conclusions/Significance: Chelating agents, such as EDTA and citrate, induce Stx phages, which raises concerns due to their frequent use in food and pharmaceutical products. This study contributes to our understanding of the phenomenon o

Seamless Insert-Plasmid Assembly at High Efficiency and Low Cost

Seamless cloning methods, such as sequence- and ligation-independent cloning (SLIC) or the Gibson assembly, are essential tools for the construction of protein expression plasmids. We here show that single-stranded gaps in double-stranded plasmids, which for example occur in typical SLIC protocols, can drastically decrease the efficiency at which the DNA transforms competent E. coli bacteria. Conversely, filling-in of single-stranded gaps using DNA polymerase resulted in increased transformation efficiency. Ligation of the remaining nicks did not lead to a further increase in transformation efficiency. These data point out a critical factor for robust seamless cloning. Highly efficient insert-plasmid assembly can be achieved by using only T5 exonuclease and Phusion DNA polymerase, without Taq DNA ligase from the original Gibson protocol, which significantly reduces the cost of the reactions. We successfully used this method with two short insert-plasmid overlap regions, each counting only 15 nucleotides

Interaction between plant species and substrate type in the removal of CO2 indoors

Elevated indoor concentrations of carbon dioxide [CO2] cause health issues, increase workplace absenteeism and reduce cognitive performance. Plants can be part of the solution, reducing indoor [CO2] and acting as a low-cost supplement to building ventilation systems. Our earlier work on a selection of structurally and functionally different indoor plants identified a range of leaf-level CO2 removal rates, when plants were grown in one type of substrate. The work presented here brings the research much closer to real indoor environments by investigating CO2 removal at a whole-plant level and in different substrates. Specifically, we measured how the change of growing substrate affects plants’ capacity to reduce CO2 concentrations. Spathiphyllum wallisii 'Verdi', Dracaena fragrans 'Golden Coast' and Hedera helix, representing a range of leaf types and sizes and potted in two different substrates, were tested. Potted plants were studied in a 0.15 m3 chamber under ‘very high’ (22000 lux), ‘low’ (~ 500 lux) and ‘no’ light (0 lux) in ‘wet’ (> 30 %) and ‘dry’ (< 20 %) substrate. At ‘no’ and ‘low’ indoor light, houseplants increased the CO2 concentration in both substrates; respiration rates, however, were deemed negligible in terms of the contribution to a room-level concentration, as they added ~ 0.6% of a human’s contribution. In ‘very high’ light D. fragrans, in substrate 2, showed potential to reduce [CO2] to a near-ambient (600 ppm) concentration in a shorter timeframe (12 hrs, e.g. overnight) and S. wallisii over a longer period (36 hrs, e.g. weekend)

Dynamics of seed protein biosynthesis in two soybean genotypes differing in drought susceptibility

The dynamics of seed storage protein biosynthesis was studied under field conditions during two vegetative seasons. Two soybean (Glycine max L. Merr.) genotypes were examined: BOS-A (drought tolerant) and L 121 (drought susceptible). Seed samples were taken from plants at three stages of seed maturation (50 and 70 d after flowering, and at full maturity). The earlier synthesis of the beta-subunit of the 7S protein occurred in the drought susceptible cultivar. We have not found such differences in the synthesis of the alpha- and alpha'-subunits of the 7S protein. Our results did not confirm significant genotypic differences in protein composition of the mature seeds between the cultivars studied, but have pointed out to the differences in the dynamics of protein biosynthesis during seed maturation and desiccation

Hybrid Power Supply System with Fuzzy Logic Controller: Power Control Algorithm, Main Properties, and Applications

This paper presents a novel power supply system based on the use of fuzzy inference logic to improve the power control of renewable energy sources. The system comprises renewable solar and wind sources, and an accumulator battery is used as an additional power source. The procedure for the parallel connection of multiple energy sources provides a stable power supply and optimal charging of the accumulative element. Renewable energy sources are connected in parallel using two serial converters and controlled by the controller based on the fuzzy logic. The reference voltage control of the serial converter enables an optimal use of available energy sources. The accumulative element is connected in parallel to compensate for the shortage of solar and wind energies, whereas if the available renewable energy exceeds the needs of the consumers, the surplus energy is accumulated in the battery. All measurements are conducted on the prototype of the hybrid power system under real conditions and compared with the applied systems of this type. This novel system is mainly used in remote telecom locations where there is no power distribution network