Boar taint detection using parasitoid biosensors

The off-flavor boar taint associated with the substances skatole, androstenone, and possibly indole represents a significant problem in the pig husbandry industry. Boar taint may occur in meat from uncastrated sexually mature male pigs; consumers commonly show a strong aversion to tainted meat. Consequently, there is a need for rapid methods to sort out and remove tainted carcasses at the slaughterline. We tested the ability of wasps, Microplitis croceipes to perceive and learn the 3 boar taint compounds both individually and in combination using classical conditioning paradigms. We also established the effectiveness and reliability of boar taint odor detection when wasps were used as biosensors in a contained system called the "wasp hound" using a cohort of trained wasps. We found that the wasps are able to successfully learn indole, skatole and to also detect them when presented a 1:1:1 mixture of all 3 compounds. This was shown for both a single hand-manipulated wasp bioassay and when using the "wasp hound" detector device. In contrast, the wasps showed a weak conditioned response to androstenone at the concentration tested. The estimated gas phase concentrations that the wasps perceived during training were in the range of 10 ± 0.4 pg/s for skatole and indole, and 2 ± 0.5 pg/s for androstenone. We conclude that use of these wasps as biosensors presents a promising method for boar taint detection and discuss future training paradigms that may improve their responses to compounds such as androstenone. Practical Application: The development of a perceptive, inexpensive, and reliable means of detecting boar taint before the product is presented to sensitive consumers.     

Kinetic Modeling of Texture and Color Changes During Thermal Treatment of Chicken Breast Meat

Heat treatment is commonly applied as a primary method for ensuring the microbial safety of poultry meat and to enhance its palatability. Although texture and color of cooked chicken breast meat are important quality parameters for the consumers that need to be controlled during thermal processing, studies assessing the temperature-time-dependent quality changes during thermal treatment are lacking. This work aims to investigate the texture and color changes of chicken breast meat during thermal processing and to develop kinetic models that describe these changes. We studied the storage modulus changes of chicken breast meat as function of temperature. The storage modulus increases from 55 °C until leveling off in an equilibrium value above 80 °C, which was attributed to microstructure changes and described with a sigmoidal function. The changes in the texture (TPA) and color (CIE L ^* a ^* b ^* ) of chicken breast meat were measured as function of temperature and time. The texture and color parameters show a rise with heating time until reaching an equilibrium value, while the rate of change increased with temperature. Kinetic models that take the non-zero equilibrium into account were developed to describe the color (lightness) and texture (hardness, gumminess, and chewiness) changes with heating time and temperature. The kinetic models provide a deeper insight into the mechanisms of texture and color changes during thermal treatment. They can be used to predict the texture and color development of chicken breast meat during thermal processing and, thus, help to optimize the process.     

Identification and analysis of possible splits for azeotropic mixtures—1. Method for column sections

The identification of possible splits at the finite reflux has been the main challenge for the creation of efficient flowsheets for the separation of azeotropic mixtures. We show in this paper that this problem can be solved by analyzing the mode of infinitely sharp splits, for which trajectories of distillation and pinch lines have special characteristics. The feasibility of sharp splits depends on the relationship of phase equilibrium constants K of components at certain points of the concentration simplex. Pinch branches and bundles of trajectories can arise only when certain relationships of K are satisfied on edges of the concentration simplex. Bundles of trajectories of both sections of column can intersect each other only at complementary relationships of these values at points of components and azeotropes. In this case, there are profiles of concentrations of both sections, which together connect the points of products with each other, i.e., a split is possible. The theory of infinitely sharp split mode determines the mentioned relationships of K. The method of infinitely sharp split mode has been developed on the base of this theory. This method includes the calculation of K at certain points of the concentration simplex. It is not iterative. Therefore, it is very fast, reliable, and can be easily programmed. For the first time, this method covers all n-component azeotropic mixtures, and all types of sharp and half-sharp splits, at which both or one product of column is sharp. This method can find unknown energy-efficient splits for different azeotropic mixtures because it is based on fundamental regularities of distillation. The automatic identification of possible splits is the basis for the synthesis of flowsheets for distillation units and for the conceptual designing of distillation columns. The theory of infinitely sharp split, the method of delimitation of product regions on elements of the concentration simplex for each section of simple columns, and the method of identification of types, characteristics, and terminals of pinch branches are considered in this article.     

Phase transitions in hydrothermal K2HPO4 solutions

A 0.1 M potassium phosphate (K₂HPO₄) solution was reacted in a flow-through cell pressurized to 22 MPa. Reduced light transmission through the cell windows was observed at a setpoint temperature ≥400 °C, along with a decrease in effluent conductivity, but with no effect on flow. These observations suggest solution separation at ∼360 °C, with accumulation of a salt-concentrated liquid in the cell body and transition of a dilute liquid to a supercritical fluid at temperature >374 °C. High-pressure differential scanning calorimetry experiments confirm an onset temperature of 354 °C with an endothermic transition at 377 °C and 22 MPa. For apparent density, ρ = 150-500 kg/m³, the average transition temperature for 0.1 M solutions, 375 ± 5 °C, is slightly elevated relative to that of water at 371 ± 4 °C. Highest deviation for 1.0 M solutions, 365 ± 15 °C, is attributed to increased K₂HPO₄ hydrolysis and polymerization reactions.     

UVM-based verification methodology for RFID-enabled smart-sensor systems

Universal verification methodology (UVM) is a standardized methodology for verifying integrated circuit designs. In this contribution, we present a UVM-based verification methodology for verifying mixed-signal smart-sensor systems. Our approach permits the validation of system functionality before implementation and also to verify the implementation on various levels of abstraction. The model-based verification approach enables to build a scalable and reusable framework, in which assertions and constrained-random stimuli are used to monitor and also to verify mixed-signal-system behavior automatically. A comprehensive example of an radio-frequency identification-based smart-sensor mixed-signal system used for bioanalytical applications is presented. Along with the designed UVM test bench architecture, we describe a novel solution for estimating the power consumption of the digital sub-system using application-specific random-activity patterns generated during UVM test bench runs (Neumann et al., Synthesis Modelling Analysis and Simulation Methods and Application to Circuit Design, SMACD, 2012).