Loss modeling and thermal measurement in planar inductors-a case study

This paper covers the experimental investigation and theoretical calculation of losses in a planar inductor under load. Finite-element software is used to perform the loss calculations. Thermally controlled experiments are performed for a range of frequencies to validate the corresponding finite-element method loss calculations. The thermal dependence of the loss mechanisms is also considered.     

Electrophilic chlorination of methane over superacidic sulfated zirconia

Catalytic chlorination of methane was studied over SO ₄ ^2– /ZrO₂, Pt/SO ₄ ^2– /ZrO₂, and Fe/Mn/SO ₄ ^2– /ZrO₂ solid superacid catalysts. The reactions were carried out in a continuous flow reactor under atmospheric pressure, at temperatures below 240°C, with a gaseous hourly space velocity of 1000 ml/g h and a methane to chlorine ratio of 4 to 1. At 200°C with 30% chlorine converted the selectivity in methyl chloride exceeds 90%. At more elevated temperatures, the selectivity decreases but stays above 80% in methyl chloride at 225°C using the sulfated zirconia catalysts. The selectivity can be enhanced by adding platinum to sulfated zirconia catalysts. An iron and manganese-doped catalyst exhibited excellent selectivities at somewhat lower conversions. Methyl chloride is obtained at 235°C in selectivities greater than 85%. No chloroform or carbon tetrachloride is formed. The electrophilic insertion involves electron-deficient metal-coordinated chlorine into the methane C-H bond.Catalysis by solid superacids, 29. For part 28 see ref. [14].     

Electrodeposition and dissolution of yttrium-hexacyanoferrate layers

The electrodeposition and dissolution of yttrium-hexacyanoferrate [YHCNFe(II)] were investigated by electrochemical quartz crystal microbalance technique (EQCM). The electrodeposition was carried out by potential cycling or stepping from solutions of Y(NO₃)₃ and K₃[Fe^III(CN)₆] of different concentrations. The ratio of the reactants was also varied. No deposition was found in dilute solutions (c < 10⁻³ mol dm⁻³). The increase of concentrations led to an intense deposition of YHCNFe(II) in the course of reduction of [Fe^III(CN)₆]³⁻. At high concentrations of the reactants a coagulation deposition of YHCNFe(III) at open-circuit has also been detected. During the reduction the first phase is the nucleation which requires saturation or oversaturation in respect to the reacting species near the gold surface. The growth phase is much faster than the formation of nuclei, and its rate depends on the concentration and the concentration ratio of the species. The composition of the deposits has been determined by total reflection X-ray fluorescence (TXRF) spectrometry. From the molar ratio of atomic constituents (K, Y and Fe) of the slightly soluble deposit (solubility: 5 × 10⁻⁵ mol dm⁻³) formed after reduction of Fe(III) a formula K_0.46Y_1.18[Fe^II(CN)₆] can be derived. This value is in good accordance with the molar mass calculated from the results of EQCM experiments which also revealed that the deposit contains ca. 2 mol H₂O/mol YHCNFe(II). The solubility of YHCNFe(III) is substantially higher (s = 2 × 10⁻³ mol dm⁻³), and according to the results of TXRF measurements, its composition is Y[Fe^III(CN)₆]. The reoxidation of YHCNFe(II) takes place in two steps. The first one is a partial oxidation which is accompanied by the desorption of K⁺ ions from the layer. During further oxidation a fast dissolution occurs due to the high solubility of YHCNFe(III).     

The ring transformations of 1,2,3,4-diepoxybutane (2,2′-bioxirane) catalysed by various aluminosilicates

The transformations of a molecule containing two adjacent epoxide rings, 2,2-bioxirane that is, were studied over various acidic aluminosilicates (HZSM-5, HY-FAU, AlMCM-41), for the first time, In the 373–473 K temperature range, in a pulse reactor, a ring-opening–ring-enlargment reaction producing furan only occured over the zeolites and it was the predominant reaction on AlMCM-41 as well. The driving force of this transformation route is water formation via elimination from 2,2-bioxirane. Suprising is the lack of the mono- or dialdehyde, the would-be products of the cleavage of the sterically more hindered C–O bonds – an acid-catalysed reaction typical for alkyl-substituted oxiranes.     

Optimal conditions for mycelial growth of Schizosaccharomyces japonicus cells in liquid medium: it enables the molecular investigation of dimorphism

The non‐pathogenic dimorphic fission yeast, Schizosaccharomyces japonicus, could be a suitable model organism for investigation of the genetic background of mycelial growth, as it has a haploid chromosome set and its genome is sequenced. Since earlier results have suggested that its morphological transition required solid substrates, but molecular biological experiments would require hyphae production in a liquid medium, we wanted to find circumstances which would enable hyphae production in liquid media. Several external conditions were investigated, but the strongest inducer was fetal bovine serum (FBS). Its positive effect could be hampered by heat and was dependent on pH, temperature and concentration of the serum. Other protein‐containing compounds, such as peptone and bovine serum albumin or amino acids, proved to be ineffective or weak. Generally, the uninduced and induced mycelial growth of Sz. japonicus could be improved by lower external pH and higher temperature. Copyright © 2014 John Wiley & Sons, Ltd.     

Investigation of the Antiproliferative Properties of Natural Sesquiterpenes from Artemisia asiatica and Onopordum acanthium on HL-60 Cells in Vitro

Plants and plant extracts play a crucial role in the research into novel antineoplastic agents. Four sesquiterpene lactones, artecanin (1), 3β-chloro-4α,10α-dihydroxy-1α,2α-epoxy-5α,7αH-guaia-11(13)-en-12,6α-olide (2), iso-seco-tanapartholide 3-O-methyl ether (3) and 4β,15-dihydro-3-dehydrozaluzanin C (4), were isolated from two traditionally used Asteraceae species (Onopordum acanthium and Artemisia asiatica). When tested for antiproliferative action on HL-60 leukemia cells, these compounds exhibited reasonable IC₅₀ values in the range 3.6–13.5 μM. Treatment with the tested compounds resulted in a cell cycle disturbance characterized by increases in the G1 and G2/M populations, while there was a decrease in the S phase. Additionally, 1–3 elicited increases in the hypodiploid (subG1) population. The compounds elicited concentration-dependent chromatin condensation and disruption of the membrane integrity, as revealed by Hoechst 33258–propidium staining. Treatment for 24 h resulted in significant increases in activity of caspases-3 and -9, indicating that the tested sesquiterpenes induced the mitochondrial pathway of apoptosis. The proapoptotic properties of the sesquiterpene lactones were additionally demonstrated withannexin V staining. Compounds 1 and 2 increased the Bax/Bcl-2 expression and decreased the expressions of CDK1 and cyclin B2, as determined at the mRNA level by means of RT-PCR. These experimental results indicate that sesquiterpene lactones may be regarded as potential starting structures for the development of novel anticancer agents.     

The behavioural response of migratory sea lamprey (Petromyzon marinus) to potential damage-released larval and migratory chemical alarm cues

We investigated the presence of damage-released alarm cues and the reactions they may cause in landlocked migratory sea lamprey (Petromyzon marinus) using semi-natural laboratory conditions during the day. In two separate experiments, migratory sea lampreys were exposed to stimuli prepared from the skinless carcasses and skin tissue of larval sea lamprey and from the skin tissue and muscle tissue of migratory sea lamprey. Migratory female sea lamprey swam significantly longer after being exposed to the stimulus prepared from the skinless carcass of larval sea lamprey. No significant changes were seen in the behaviour of the migratory female lamprey in response to larval skin extract or in the behaviour of male sea lamprey to any experimental extract in the larval extract experiment. In the second experiment that utilised migratory lamprey stimuli, neither male and nor female migratory sea lamprey showed a significant difference in their behavioural response among different treatments and controls. Our findings indicate that adult female sea lamprey respond strongly to damage-released alarm cues from larval sea lamprey; hence, the latter holds promise for sea lamprey behavioural manipulations for control purposes during the day. Further research is needed to examine responses to damage-released alarm cues at night, when migratory sea lampreys are more active.     

Theoretical investigation of catalytic HCO3 hydrogenation in aqueous solutions

Density functional theory along with a dielectric continuum solvation model has been applied to identify possible reaction intermediates for the catalytic hydrogenation of HCO₃⁻ anion into HCO₂⁻ that occurs in aqueous solutions in the presence of water-soluble ruthenium complexes. Bicarbonate ion is shown to coordinate to a Ru-dihydride species, which then undergoes a protonation process that yields a CO₂ complex. The CH bond formation is found to take place via CO₂ insertion into a RuH bond and the direct elimination of the formate product is shown to be an energetically favored step, which is assisted by the water medium. We find that water is directly involved in the reaction as a protonating/deprotonating agent and also acts as a coordinating ligand.