Relation of α2-Antiplasmin Genotype and Genetic Determinants of Fibrinogen Synthesis and Fibrin Clot Formation with Vascular Endothelial Growth Factor Level in Axial Spondyloarthritis

Objective: Coagulation and fibrinolysis are interrelated with the expression of vascular endothelial growth factor (VEGF), which frequently is increased in axial spondyloarthritis (axSpA). We tested whether (i) α₂-antiplasmin (A2AP) Arg6Trp, (ii) fibrinogen, factor XIII A-subunit or B-subunit genotypes are associated with VEGF levels and assessed whether the known association between elevated VEGF and radiographic spinal progression in axSpA depends on genetic background. Methods: One hundred and eighty-six axSpA patients from the German Spondyloarthritis Inception Cohort were genotyped, characterized for VEGF levels, and statistically analyzed. The association between VEGF and radiographic spinal progression was assessed in dependence on genetic background in stratified analyses. Results: A2AP 6Trp carriage was associated with VEGF elevation (OR: 2.37, 95% CI: 1.06–5.29) and VEGF levels (6Trp, 455 ± 334 pg/mL; 6Arg/Arg, 373 ± 293 pg/mL; p < 0.008). Association between elevated VEGF and radiographic spinal progression in axSpA (OR: 3.11, 95% CI: 1.02–8.82) depended remarkably on the fibrinogen (FGA) genotype. When considering axSpA patients with elevated VEGF, in FGA rs6050A>G wild types, 42.1% of patients (8 of 19) progressed, while in G-allele carriers, no radiographic progression happened (0 of 13) (p < 0.04). Conclusions: The A2AP Arg6Trp genotype seems to influence VEGF levels in axSpA. The predictive value of VEGF elevations in respect of radiographic spinal progression in axSpA depends on FGA genotypes.     

Paper bioassay based on ceria nanoparticles as colorimetric probes

We report the first use of redox nanoparticles of cerium oxide as colorimetric probes in bioanalysis. The method is based on changes in the physicochemical properties of ceria nanoparticles, used here as chromogenic indicators, in response to the analyte. We show that these particles can be fully integrated in a paper-based bioassay. To construct the sensor, ceria nanoparticles and glucose oxidase were coimmobilized onto filter paper using a silanization procedure. In the presence of glucose, the enzymatically generated hydrogen peroxide induces a visual color change of the ceria nanoparticles immobilized onto the bioactive sensing paper, from white-yellowish to dark orange, in a concentration-dependent manner. A detection limit of 0.5 mM glucose with a linear range up to 100 mM and a reproducibility of 4.3% for n = 11 ceria paper strips were obtained. The assay is fully reversible and can be reused for at least 10 consecutive measurement cycles, without significant loss of activity. Another unique feature is that it does not require external reagents, as all the sensing components are fixed onto the paper platform. The bioassay can be stored for at least 79 days at room temperature while maintaining the same analytical performance. An example of analytical application was demonstrated for the detection of glucose in human serum. The results demonstrate the potential of this type of nanoparticles as novel components in the development of robust colorimetric bioassays.     

2D Elastodynamics of Interface Microcracks: The Effect of Cracks Interaction

The study is devoted to a 2D problem for interface cracks under harmonic external loading. The system of boundary integral equations for displacements and tractions is derived from the dynamic Somigliana identity. The distributions of the displacements and tractions at the bonding interface and the surface of the cracks are analysed for the normally incident tension-compression wave. The dynamic stress intensity factors are also computed for different values of the frequency of the incident wave and the distance between cracks. The effect of distance between cracks on the solution of the problem is studied.     

Consumer acceptability of dark, firm and dry (DFD) and normal pH beef steaks

The sensory attributes of dark, firm and dry (DFD) and normal pH beef, both raw and fried, were evaluated and compared by a consumer panel (n=64). Consumer sensory evaluations indicated that the general appearance (P<0.05), colour (P<0.001) and acceptability (P<0.01) of raw normal pH steaks were preferred to those of raw DFD steaks. Twice as many panellists preferred the raw normal pH than raw DFD steaks because of the more attractive red colour, compared to the almost black colour of raw DFD steaks. No significant differences were found between the hedonic ratings of the sensory attributes of fried normal pH and fried DFD steaks. It was expected but not confirmed that consumers would find the tenderness of the DFD steaks more acceptable compared to the normal pH steaks. However, when forced to choose, female consumers significantly preferred fried normal pH steaks to fried DFD steaks, presumably because of a better flavour and more acceptable colour.     

NATURAL CONVECTION AND SOLID PHASE COMBUSTION

Self-propagating high-temperature synthesis (SHS) is a combustion process involving two or more solid reactants. The typical SHS configuration consists of a cylindrical preform of mixed powders, placed in an inert gas chamber, and ignited at one end. In past studies, interaction between the solid phase and the ambient gas phase has been limited to heat losses from the solid; the influence of natural convection on the solid phase has never been considered. In this study, computational fluid dynamics (CFD) is used, and it is shown that intense convection flow develops in the proximity of the combustion front. Gas flows adjacent to reacted solid material, heats up, and when it reaches the unreacted solid heat is transferred from the gas to the solid phase, which aids solid phase thermal conduction in preheating the material. The effect is stronger than expected, and it could stabilize the combustion of structured reactants like roll-ups of foils and wires. Combustion parallel and antiparallel to gravity is investigated for different burning velocities. At low propagation velocities, the natural convection cell forms a torus that is seated above the combustion front. At high propagation velocities, the convection flow cannot track the combustion front, and Tollmien-Schlichting waves form. Constant front propagation and planar oscillations of the combustion front lead to increasingly complex flows. Finally, the heat exchange between the gas and solid for constant front propagation is compared to analytical solutions.     

Differentiation of Brewing and Related Yeasts Based on PCR Amplification and Restriction Fragment Length Polymorphism of Ribosomal DNA

A study to differentiate commercially applied brewing yeasts selected from the culture collection of the University of the Free State from related yeasts of the genus Saccharomyces using PCR amplification and RFLP of the internal transcribed spacers region was conducted. Differentiation was dependent on the restriction enzymes used to digest the amplified rDNA. Digestion with Hae III, Cfo I, Sau 3AI and Msp I divided representatives of the genus Saccharomyces into several unique groups. With Msp I the DNA patterns for the two brewing strains were similar, but could be differentiated from Sacch. cerevisiae and other species tested. It was also possible to distinguish some members of the Saccharomyces sensu stricto group i.e. Sacch. bayanus and Sacch. pastorianus from Sacch. cerevisiae and Sacch. paradoxus using Hae III as well as Sacch. paradoxus from the other sensu stricto members using Msp I digestion.     

THE VALUE OF LONG-CHAIN FATTY ACID COMPOSITION IN THE IDENTIFICATION OF SOME BREWERY YEASTS

The cellular long-chain fatty acids of 72 strains representing 29 species of brewery yeasts were extracted by saponification and analysed as methyl esters by gas chromatography. With this method, it was possible to distinguish between Saccharomyces cerevisiae and five other groups from the brewery industry, only four hours after they were obtained from 48 h old cultures under standard conditions. This compares favourably with the 7 to 10 days for conventional methods.