Electrical,morphological and structural properties of RF magnetron sputtered Mo thin films for application in thin film photovoltaic solar cells

Molybdenum (Mo) thin films were deposited using radio frequency magnetron sputtering, for application as a metal back contact material in “substrate configuration” thin film solar cells. The variations of the electrical, morphological, and structural properties of the deposited films with sputtering pressure, sputtering power and post-deposition annealing were determined. The electrical conductivity of the Mo films was found to increase with decreasing sputtering pressure and increasing sputtering power. X-ray diffraction data showed that all the films had a (110) preferred orientation that became less pronounced at higher sputtering power while being relatively insensitive to process pressure. The lattice stress within the films changed from tensile to compressive with increasing sputtering power and the tensile stress increased with increasing sputtering pressure. The surface morphology of the films changed from pyramids to cigar-shaped grains for a sputtering power between 100 and 200 W, remaining largely unchanged at higher power. These grains were also observed to decrease in size with increasing sputtering pressure. Annealing the films was found to affect the resistivity and stress of the films. The resistivity increased due to the presence of residual oxygen and the stress changed from tensile to compressive. The annealing step was not found to affect the crystallisation and grain growth of the Mo films.     

Hetero-azeotropic distillation: combining fungal dehydration and lipid extraction

A low-cost single-stage laboratory process combining fungal dehydration and lipid extraction was compared with a traditional two-stage method employing freeze-drying and subsequent mechanical disruption in the presence of solvent. The ability of a number of organic solvents to form hetero-azeotropes with water was exploited. Chloroform, cyclohexane and hexane were assessed in their abilities to both dry and extract lipid from the oleaginous phycomycete Mortierella alpina (ATCC 32222). Drying rate and lipid extraction were maximised under conditions that prevented fungal agglomeration. The total processing time was limited by the rate of dehydration rather than by the rate of lipid extraction. In all cases azeotropic distillation facilitated a greater rate of dehydration than was possible with freeze-drying. A consequent reduction in overall processing time was observed. Uniquely, both the solvent used and the mode of mixing employed controlled the morphology of the aggregates formed during distillation. In combination with mild mixing chloroform discouraged agglomeration whereas cyclohexane and hexane promoted aggregation. Successful lipid extraction was dependent on the use of dry biomass rather than on the application of heat to effect distillation. Neither the application of heat nor the solvent employed had any significant effect on the lipid composition of the extracted oil.     

Isolation of monoclonal antibodies monospecific for bovine beta-lactoglobulin.

Monoclonal antibodies were generated against purified bovine beta-lactoglobulin A. Six antibodies reactive only with beta-lactoglobulin were selected. At least one of the antibodies appeared to be species monospecific for bovine beta-lactoglobulin. The remaining five antibodies recognized proteins in caprine and porcine whey fractions. One monoclonal antibody (59-1) exhibited a distinct 2:1 preference for beta-lactoglobulin B over A at near neutral pH (7.5). These antibodies should prove extremely useful adjuncts in structural studies of bovine beta-lactoglobulin.     

Preliminary investigation of the application of Raman spectroscopy to the prediction of the sensory quality of beef silverside

The potential of Raman spectroscopy for the determination of meat quality attributes has been investigated using data from a set of 52 cooked beef samples, which were rated by trained taste panels. The Raman spectra, shear force and cooking loss were measured and PLS used to correlate the attributes with the Raman data. Good correlations and standard errors of prediction were found when the Raman data were used to predict the panels' rating of acceptability of texture (R²=0.71, Residual Mean Standard Error of Prediction (RMSEP)% of the mean (μ)=15%), degree of tenderness (R²=0.65, RMSEP% of μ=18%), degree of juiciness (R²=0.62, RMSEP% of μ=16%), and overall acceptability (R²=0.67, RMSEP% of μ=11%). In contrast, the mechanically determined shear force was poorly correlated with tenderness (R²=0.15). Tentative interpretation of the plots of the regression coefficients suggests that the -helix to β-sheet ratio of the proteins and the hydrophobicity of the myofibrillar environment are important factors contributing to the shear force, tenderness, texture and overall acceptability of the beef. In summary, this work demonstrates that Raman spectroscopy can be used to predict consumer-perceived beef quality. In part, this overall success is due to the fact that the Raman method predicts texture and tenderness, which are the predominant factors in determining overall acceptability in the Western world. Nonetheless, it is clear that Raman spectroscopy has considerable potential as a method for non-destructive and rapid determination of beef quality parameters.     

Cell interaction microarray for blood phenotyping

Microarrays promise great advances in areas of diagnostic testing where there is a need to perform multiple assays in parallel. In the short term, protein microarrays have a greater potential to impact diagnostics than DNA arrays due to their potential for direct sample measurements. Here, we report an antibody microarray technique for selectively recognizing glycan and peptide motifs on the surface of red blood cells. We present results demonstrating the optimization and efficacy of the microarray approach as a highly sensitive and specific microscale multiplex assay for blood typing. We also show that our microarray can be used to screen red blood cell surface antigens using whole blood in a label-free detection mode. Finally, our results indicate this method has potential for broader applications in biochip medicine.