Direct observation of dislocation dissociation and Suzuki segregation in a Mg–Zn–Y alloy by aberration-corrected scanning transmission electron microscopy

Crystal defects in a plastically deformed Mg–Zn–Y alloy have been studied on the atomic scale using aberration-corrected scanning transmission electron microscopy, providing important structural data for understanding the material’s deformation behavior and strengthening mechanisms. Atomic scale structures of deformation stacking faults resulting from dissociation of different types of dislocations have been characterized experimentally, and modeled. Suzuki segregation of Zn and Y along stacking faults formed through dislocation dissociation during plastic deformation at 300 °C is confirmed experimentally on the atomic level. The stacking fault energy of the Mg–Zn–Y alloy is evaluated to be in the range of 4.0–10.3 mJ m^?2. The newly formed nanometer-wide stacking faults with their Zn/Y segregation in Mg grains play an important role in the superior strength of this alloy at elevated temperatures.     

Characteristics of Electrodeposited Chromium

Organic complexants are essential components for the electrodeposition of chromium from chromium (III) based electrolytes. However, during electrolysis these complexants suffer decomposition and their compounds become incorporated in the deposit. The properties are considerably altered by the presence of these inclusions. In this paper the effect of addition of glycine to a high speed and still chromium (III) electrolyte was studied. Component analysis of the deposits indicated the presence of carbon, nitrogen and hydrogen. The effects of current density, concentration of complexant, bath temperature and electrolyte velocity on the concentration of the above elements are presented.

The hardness of the deposits was greatly increased after heat treatment at 400 to 800° C. X-ray diffraction show the as-deposited chromium to be amorphous and the formation of carbide compounds after heat treatment.

The corrosion behaviour of chromium deposits was investigated by using salt spray test and electrochemical techniques.     

Mixed valence complexes involving MM quadruple bonds (M=Mo or W)

The MM quadruple bond of configuration MM sigma2pi4delta2 is redox active and in many ways ideally suited for studies of mixed valency when two or more such centres are linked by a bridging ligand. In this account, the mechanism of electronic coupling is examined for complexes of the type [L3M2bridgeM2L3]0/+ where L, a pivalate; bridge, a dicarboxylate or related ligand and M, Mo or W. The represented examples allow us to probe electronic factors close to the class II/III border and readily distinguish between electron and hole transfer in the superexchange mechanism. The potential for mixed valence organic radical anions mediated by the M2 centre is also raised and one specific example of class III behaviour is described.     

Development of real-time PCR assays for the detection of Atlantic cod (Gadus morhua), Atlantic salmon (Salmo salar) and European plaice (Pleuronectes platessa) in complex food samples

We have developed species-specific real-time PCR assays for the identification of Atlantic cod (Gadus morhua), Atlantic salmon (Salmo salar) and European plaice (Pleuronectes platessa) in food products. The species-specific assays, comprising a set of primers and probe for each species, were designed using genomic genes (pantophysin for Atlantic cod, growth hormone for Atlantic salmon and parvalbumin for European plaice) which were then optimised for specificity and selectivity. The sensitivity and the effect of heat and pressure on amplification efficiency were then determined for each assay. These assays were then used to analyse DNA extracted from commercial fish products and model food samples spiked with each of the fish species. The target species was successfully identified in all samples analysed, demonstrating the applicability of these assays to the analysis of food products.     

Toward quantitative fetal heart rate monitoring

Continuous electronic fetal heart rate (FHR) monitoring during labor is motivated by the clinical experience that fetal distress causes loss of FHR variation and the occurrence of decelerations late during uterine contraction. This practice is of uncertain clinical benefit, perhaps because the interpretation is qualitative. We have developed new quantitative measures and analyzed cardiotocograph records from 148 consecutive patients, 44 of whom had at least one "nonreassuring" epoch. In multivariate regression models, measures of deceleration and variability were significantly associated with the obstetrician's diagnosis (receiver operating characteristic area 0.84, p < 0.05). This approach may be useful clinically.     

The Development of Species-specific Real-time PCR Assays for the Detection of Pheasant and Quail in Food

The development of species-specific real-time PCR assays for the detection of pheasant and quail in commercial food products are reported. Real-time PCR primer and probe sets were designed to detect the mitochondrial cytochrome b gene of pheasant (Phasianus colchicus) and quail (Coturnix coturnix) and were optimized to achieve species specificity. The efficiency and sensitivity of the assays were determined and their applicability to the analysis of commercial samples assessed. The assays successfully detected pheasant and quail in complex food matrices of raw, oven-cooked, and autoclaved meat, demonstrating their suitability for use in enforcement and food control laboratories.