The value of carcass weight, fat depth measures and eye muscle area for predicting the percentage yield of saleable meat in Australian grass-fed beef carcasses for Japan

The percentage saleable meat yield was determined for 42 carcasses from grass-fed steers representing a range of breed types purchased in Australia for the Japanese market. Their mean (s.d.) carcass weight and P8 fat depth were 329 (28.1) kg and 17.3 (4.3) mm, respectively. All measures of subcutaneous fat depth were significantly (P < 0.05) and moderately correlated with percentage saleable meat yield, with measures in the loin region showing a stronger association than those taken in the rump region. The association between P8 fat depth and the loin measures of subcutaneous fat were low and there was a significant (P < 0.05) association only between P8 and fat depth at the 10th rib (FD 10). The use of fat depth measurements from the loin region reduced the error associated with predicting saleable meat yield more than those from the rump region and significantly increased the amount of variation (R(2)) in saleable meat yield that was explained. Hot carcass weight (HCW) did not significantly (P > 0.05) improve prediction models when combined with subcutaneous fat depth measurements and overall, the R(2) values were low ranging from 0.19 to 0.42. The models indicated that fat depth measures and carcass weight are poor predictors of percentage meat yield in heavy-weight carcasses from mixed breed cattle as produced and processed in Australia. The prediction of percentage yield was in general significantly (P < 0.05) improved when measures of M. longissimus thoracis et lumborum (LD) area were added as independent variables to models based on hot carcass weight and subcutaneous fat depth measurements. With LD area added the amount of variation in yield that could be explained by the models increased by as much as 28%. Overall, the best model was based on fat depth at the 12th rib and LD area measured at the 5th rib for which the R(2) was 0.58 and the residual standard deviation was 1.63%. The next most accurate prediction of yield was provided by a model which included the independent variables used in the Australian Chiller Assessment Scheme namely HCW, FD10 and LD area at the 10th rib upon which breed type had no significant (P > 0.05) effect.     

Exogenous Proteases for Meat Tenderization

The use of exogenous proteases to improve meat tenderness has attracted much interest recently, with a view to consistent production of tender meat and added value to lower grade meat cuts. This review discusses the sources, characteristics, and use of exogenous proteases in meat tenderization to highlight the specificity of the proteases toward meat proteins and their impact on meat quality. Plant enzymes (such as papain, bromelain, and ficin) have been extensively investigated as meat tenderizers. New plant proteases (actinidin and zingibain) and microbial enzyme preparations have been of recent interest due to controlled meat tenderization and other advantages. Successful use of these enzymes in fresh meat requires their enzymatic kinetics and characteristics to be determined, together with an understanding of the impact of the surrounding environmental conditions of the meat (pH, temperature) on enzyme function. This enables the optimal conditions for tenderizing fresh meat to be established, and the elimination or reduction of any negative impacts on other quality attributes.

[Supplementary materials are available for this article. Go to the publisher's online edition of Critical Reviews in Food Science and Nutrition for the following free supplemental files: Additional text, tables, and figures.]     

Purely Elastic Fluid–Structure Interactions in Microfluidics: Implications for Mucociliary Flows

Fluid–structure interactions lie at the heart of the complex, and often highly coordinated, motions of actively driven microscale biological systems (e.g., translating cilia, flagella, and motile cells). Due to the highly viscoelastic nature of most relevant biological fluids and the small length scales involved, the viscous and inertial forces in such flows are dominated by elasticity. However, elastic effects are often overlooked in studies seeking to address phenomena like the synchronization of beating cilia. In this study, unique microfluidic experiments are presented to demonstrate that inertia‐free viscoelastic flows can lead to highly regular beating of an immersed (passive) flexible structure, herein named “purely‐elastic” fluid–structure interaction. It is also shown how two such flexible structures can achieve an extraordinary degree of synchronization, with a correlation coefficient approaching unity. The synchronization is a result of the generation of localized elastic stresses in the fluid that effectively link the two objects. These purely elastic interactions may be important to consider toward developing a complete understanding of the motions of microscale biological systems.     

Hydrogen compression characteristics of a dual stage thermal compressor system utilizing LaNi5 and Ca0.6Mm0.4Ni5 as the working metal hydrides

The research performed herein consisted of the design, construction, and testing of a dual stage metal hydride hydrogen compression system intended to be used with lower grade geothermal or waste energy sources. The metal hydrides used in this study were LaNi₅ and Ca_0.6Mm_0.4Ni₅. A Finite Time Thermodynamics (FTT) model was also developed and the model proved useful in determining how the compression results and energy requirements for the system change with variations in the system parameters. Dual stage system results showed a final compression ratio of approximately 12 when using cooling and heating temperatures of 10 °C and 90 °C, respectively. The final output pressures and compression ratios were found to follow an upward trend when increasing the heating bath temperatures. It can be concluded from the experimental results, that though the dual stage hydrogen compression system has room for improvement, it is an effective way of compressing the hydrogen from low initial pressures while using low grade energy sources.     

Comparison of Thermal Conductivity and Thermal Boundary Conductance Sensitivities in Continuous-Wave and Ultrashort-Pulsed Thermoreflectance Analyses

Thermoreflectance techniques are powerful tools for measuring thermophysical properties of thin film systems, such as thermal conductivity, Λ, of individual layers, or thermal boundary conductance across thin film interfaces (G). Thermoreflectance pump–probe experiments monitor the thermoreflectance change on the surface of a sample, which is related to the thermal properties in the sample of interest. Thermoreflectance setups have been designed with both continuous wave (cw) and pulsed laser systems. In cw systems, the phase of the heating event is monitored, and its response to the heating modulation frequency is related to the thermophysical properties; this technique is commonly termed a phase sensitive thermoreflectance (PSTR) technique. In pulsed laser systems, pump and probe pulses are temporally delayed relative to each other, and the decay in the thermoreflectance signal in response to the heating event is related to the thermophysical properties; this technique is commonly termed a transient thermoreflectance (TTR) technique. In this work, mathematical models are presented to be used with PSTR and TTR techniques to determine the Λ and G of thin films on substrate structures. The sensitivities of the models to various thermal and sample parameters are discussed, and the advantages and disadvantages of each technique are elucidated from the results of the model analyses.