Carcinogenic polycyclic aromatic hydrocarbons increase intracellular Ca2+ and cell proliferation in primary human mammary epithelial cells

A method was developed to determine in eggs 2 components [4,6-dimethyl-2-hydroxypyrimidine and 1,3-bis(4-nitrophenyl)urea] of the anticoccidial drug nicarbazin, used to treat poultry. Samples were extracted with acetonitrile, and the extracts were washed with hexane and evaporated to dryness before analysis by liquid chromatography/mass spectrometry with atmospheric pressure chemical ionization. By switching from positive to negative ion monitoring and using gradient elution, both components were measured within one run. The limit of quantitation of the assay was 10 ng/g for each component. The results of a preliminary feeding trial in which chickens were fed contamination levels of the drug are also reported.     

Identification of the blood-borne somatotroph-differentiating factor during chicken embryonic development

Somatotrophs become a significant population by day 16 of chicken embryonic development. We have previously demonstrated that an earlier induction of GH cell differentiation is possible with the addition of day 16 embryonic serum to cultures of day 12 pituitary cells, an age when somatotrophs are rare. The present study was designed to identify the blood-borne signal(s) responsible for the serum activity, using reverse hemolytic plaque assays to identify individual GH-secreting cells. The activity was found to be a heat-stable, ether-soluble compound(s) that is bound or inhibited by a trypsin-sensitive protein. The extent of GH cell differentiation was greater (P < 0.05; n = 3) in response to the ether phases of heated day 16 (14.1 +/- 0.4% of all cells) and day 12 sera (9.3 +/- 0.4%) than with untreated serum from days 16 and 12 (6.1 +/- 0.4% and 0.82 +/- 0.4%, respectively). Furthermore, ether-extracted day 16 serum was more effective than ether-extracted day 12 serum, which was also different from basal (0.85 +/- 0.4%; P < 0.05). Based on this biochemical profile, the abilities of various steroids to stimulate differentiation were tested. Three steroids were found to stimulate somatotroph differentiation in vitro: 17beta-estradiol, corticosterone, and progesterone. However, the estradiol receptor antagonist, tamoxifen, while abolishing the effect of estradiol, had no effect on the induction of differentiation by day 16 serum. In contrast, RU486, a specific glucocorticoid receptor antagonist in chickens, blocked the stimulatory effects of corticosterone, progesterone, and day 16 serum on somatotroph differentiation. We next tested whether the active compound in day 16 embryonic serum was corticosterone, the predominant glucocorticoid in chickens. Incubation of day 16 serum with corticosterone antiserum, but not control antiserum, suppressed day 16 serum-induced GH cell differentiation. Therefore, we conclude that corticosterone is the blood-borne signal capable of stimulating somatotroph differentiation in vitro. The present findings together with previous reports indicate that somatotroph differentiation during embryonic development may result from an increase in circulating glucocorticoid concentrations.     

The adsorption of coumarin at solid metal electrodes

The effect of coumarin on the “deposition potential” of a number of metals at solid metal surfaces has been compared with that at a dropping mercury electrode. These results have been used to interpret the adsorption of coumarin on different metal surfaces and to suggest that Tl⁺ and Pb²⁺ ions are specifically adsorbed on mercury and that Tl⁺, Co²⁺, Fe²⁺, Ni²⁺ and Zn²⁺ are specifically adsorbed on their parent metals.     

Criteria for approval of mining equipment incorporating on-boardswitching of high-voltage circuits

The US Mine Safety and Health Administration (MSHA) recently developed criteria to modify the current regulation prohibiting the on-board switching of high-voltage circuits (>1000 V AC). Extensive research conducted by the US Bureau of Mines and MSHA provided the basis for the development of safe and viable criteria. Under the provisions of Title 30 Code of Federal Regulations, Section 18.82, experimental permits were issued to high-voltage continuous miners and longwall systems incorporating this new technology. The information gathered from the operation of this equipment in the field along with industry concerns and recommendations were considered during the finalization of these criteria     

Characterisation of CYP102A25 from Bacillus marmarensis and CYP102A26 from Pontibacillus halophilus: P450 Homologues of BM3 with Preference towards Hydroxylation of Medium‐Chain Fatty Acids

Cytochrome P450 monooxygenases are highly desired biocatalysts owing to their ability to catalyse a wide variety of chemically challenging C?H activation reactions. The CYP102A subfamily of enzymes are natural catalytically self‐sufficient proteins consisting of a haem and FMN‐FAD reductase domain fused in a single‐component system. They catalyse the oxygenation of saturated and unsaturated fatty acids to produce primarily ω?1, ω?2 and ω?3 hydroxy acids. These monooxygenases have potential applications in biotechnology; however, their substrate range is still limited and there is a continued need to add diversity to this class of biocatalysts. Herein, we present the characterisation of two new members of this class of enzymes, CYP102A25 (BMar) from Bacillus marmarensis and CYP102A26 (PHal) from Pontibacillus halophilus, both of which express readily in a recombinant bacterial host. BMar exhibits the highest activity toward myristic acid and shows moderate activity towards unsaturated fatty acids. PHal exhibits broader activity towards mid‐chain‐saturated (C₁₄–C₁₈) and unsaturated fatty acids. Furthermore, PHal shows good regioselectivity for the hydroxylation of myristic acid, targeting the ω?2 position for C?H activation.     

Evaluation of polycaprolactone − poly‐D,L‐lactide copolymer as biomaterial for breast tissue engineering

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry     

Bayesian Inference for ARFIMA Models

This article develops practical methods for Bayesian inference in the autoregressive fractionally integrated moving average (ARFIMA) model using the exact likelihood function, any proper prior distribution, and time series that may have thousands of observations. These methods utilize sequentially adaptive Bayesian learning, a sequential Monte Carlo algorithm that can exploit massively parallel desktop computing with graphics processing units (GPUs). The article identifies and solves several problems in the computation of the likelihood function that apparently have not been addressed in the literature. Four applications illustrate the utility of the approach. The most ambitious is an ARFIMA(2,d,2) model for the Campito tree ring time series (length 5405), for which the methods developed in the article provide an essentially uncorrelated sample of size 16,384 from the exact posterior distribution in under four hours. Less ambitious applications take as little as 4 minutes without exploiting GPUs.     

Microstructural Analysis and Transport Properties of Thermally Sprayed Multiple-Layer Ceramic Coatings

Multilayer, graded ceramic/metal coatings were prepared by an air plasma spray method on Ti-6Al-4V, 4140 steel and graphite substrates. The coatings were designed to provide thermal barriers for diesel engine pistons to operate at higher temperatures with improved thermal efficiency and cleaner emissions. A systematic, progressive variation in the mixture of yttria-stabilized zirconia and bondcoat alloys (NiCoCrAlYHfSi) was designed to provide better thermal expansion match with the substrate and to improve thermal shock resistance and cycle life. Heat transfer through the layers was evaluated by a flash diffusivity technique based on a model of one-dimensional heat flow. The aging effect of the as-sprayed coatings was captured during diffusivity measurements, which included one heating and cooling cycle. The hysteresis of thermal diffusivity due to aging was not observed after 100-h annealing at 800 °C. The measurements of coatings on substrate and freestanding coatings allowed the influence of interface resistance to be evaluated. The microstructure of the multilayer coating was examined using scanning electron microscope and electron probe microanalysis.     

Modelling methods for co-fired pulverised fuel furnaces

Co-firing of biomass and coal can be beneficial in reducing the carbon footprint of energy production. Accurate modelling of co-fired furnaces is essential to discover potential problems that may occur during biomass firing and to mitigate potential negative effects of biomass fuels, including lower efficiency due to lower burnout and NOx formation issues. Existing coal combustion models should be modified to increase reliability of predictions for biomass, including factors such as increased drag due to non-spherical particle sizes and accounting for organic compounds and the effects they have on NOx emission. Detailed biomass co-firing models have been developed and tested for a range of biomass fuels and show promising results.     

Thermophysical Properties of ZrB2 and ZrB2–SiC Ceramics

Thermophysical properties were investigated for zirconium diboride (ZrB₂) and ZrB₂–30 vol% silicon carbide (SiC) ceramics. Thermal conductivities were calculated from measured thermal diffusivities, heat capacities, and densities. The thermal conductivity of ZrB₂ increased from 56 W (m K)⁻¹ at room temperature to 67 W (m K)⁻¹ at 1675 K, whereas the thermal conductivity of ZrB₂–SiC decreased from 62 to 56 W (m K)⁻¹ over the same temperature range. Electron and phonon contributions to thermal conductivity were determined using electrical resistivity measurements and were used, along with grain size models, to explain the observed trends. The results are compared with previously reported thermal conductivities for ZrB₂ and ZrB₂–SiC.