The effect of enzyme systems and processing on the hydrolysis of peanut (Arachis hypogaea L.) protein

In vitro protein digestion studies were carried out on raw and roasted peanut flour as the starting material in the production of peanut protein hydrolysate. Peanut flour was hydrolyzed with alcalase and alternately in a sequential digestion with pepsin-pancreatin, both for up to 24 h. The degree of hydrolysis (DH) at different times of hydrolysis was determined using the trinitrobenzenesulfonic acid (TNBS) method. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to indicate destruction of native protein units in the enzymatic digests.Hydrolysis with alcalase was very rapid for the first 6 h after which a plateau was reached, whereas that with pepsin–pancreatin was more gradual reaching a plateau after 12 h of hydrolysis. Raw peanut hydrolyzed with alcalase and pepsin–pancreatin had 23% and 21% DH after 24 h respectively, whilst roasted peanut hydrolyzed with alcalase had 21% DH, with the pepsin–pancreatin hydrolysate recording the highest value of 25% after 24 h of hydrolysis.SDS-PAGE results showed that raw peanut samples behaved differently from the roasted samples; increasing hydrolysis time reduced larger peanut protein subunits, with only peptides of <20 kDa visible after hydrolysis for raw peanut, and virtually no distinct visible bands for the roasted peanut after 3 h of hydrolysis.     

Viscous Lubrication in Wire Drawing

A scheme for the promotion of viscous lubrication in wire drawing is analyzed. Lubricant pressure is built up by means of close tolerance tube installed in front of the die. In the die, plasticity is maintained by the combination of fluid pressure and wire tension. In the analysis presented here the lubricant flow rate and film thickness variation in the die are solved for as well as the necessary length of pressure tube. Pressure and temperature effects on the lubricant viscosity and strain hardening effects on the wire metal are included in the analysis.     

Oocysts of Cryptosporidium parvum and model sand surfaces in aqueous solutions: an atomic force microscope (AFM) study

Oocysts of C. parvum have been associated with several waterborne outbreaks of gastro-enteric disease. Currently, one of the main barriers to oocyst contamination of drinking waters is provided by sand-bed filtration. In this study an atomic force microscope (AFM) has been used to measure the force of interaction between oocysts of C. parvum and a model sand surface (silicate glass). The AFM force curves have been compared and contrasted with the corresponding electrical potentials obtained from electrophoretic measurements (zeta). It has been found that the surface of C. parvum oocysts possesses a hairy layer, most likely a result of surface proteins extending into solution. The hairy layer imposes a steric repulsion between the oocyst and sand surface, in addition to any electrostatic repulsion. The hairy layer collapsed to varying extents in the presence of dissolved calcium and dissolved organic carbon, indicating that the oocysts may be more readily adsorbed onto the model sand surface under these conditions. Conversely, as the two surfaces are pulled apart, the occasional attachment of oocyst surface proteins to the model sand surface can result in adhesion. The AFM results offer new insights into the oocyst surface of C. parvum, and the mechanism of interaction with model sand surfaces under conditions relevant to sand-bed filtration.     

Fault identification for robot manipulators

Several factors must be considered for robotic task execution in the presence of a fault, including: detection, identification, and accommodation for the fault. In this paper, a nonlinear observer is used to identify a class of actuator faults once the fault has been detected by some other method. Advantages of the proposed fault-identification method are that it is based on the nonlinear dynamic model of a robot manipulator (and hence, can be extended to a number of general Euler Lagrange systems), it does not require acceleration measurements, and it is independent from the controller. A Lyapunov-based analysis is provided to prove that the developed fault observer converges to the actual fault. Experimental results are provided to illustrate the performance of the identification method.     

The effect of transdermal nicotine on digital perfusion in reformed habitual smokers

The effects of transdermal nicotine-assisted smoking cessation on digital perfusion and health-related quality of life were assessed in 10 chronic smokers. Components of digital blood flow were evaluated by digital temperature and laser Doppler fluxmetry before, during, and after a standardized cold challenge. Nutritional flow was measured by vital capillaroscopy; a quantitative perfusion profile was obtained by laser Doppler perfusion imaging. A battery of validated measures were used to evaluate health-related quality of life. The microvascular response of smokers was evaluated before smoking cessation and at 2 and 7 days after smoking cessation and was compared with the response of nonsmoking controls. Results demonstrated that a (1) cutaneous microvascular perfusion was lower in smokers than nonsmokers, (2) the acute administration of transdermal nicotine did not decrease cutaneous perfusion, (3) smoking cessation and transdermal nicotine normalized digital microvascular perfusion by 7 days, and (4) transdermal nicotine and smoking cessation did not negatively impact health-related quality of life.     

Fate of Escherichia coli O157:H7 in ground apples used in cider production

Survival of Escherichia coli O157:H7 in ground Golden Delicious, Red Delicious, Rome, and Winesap apples stored at 4, 10, and 25 degrees C was determined. E. coli O157:H7 populations were monitored for up to 18 days (4 degrees C), 12 days (10 degrees C), and 5 days (25 degrees C), when mold contamination became visible. At 25 degrees C, Red Delicious apples supported survival of E. coli O157:H7 better (P < 0.05) than the other cultivars, followed by Golden Delicious and Rome apples, which were not statistically different (P > 0.05). Winesap apples were the least favorable (P < 0.05) for survival of E. coli O157:H7 at 25 degrees C. E. coli O157:H7 was recovered at similar rates from Golden Delicious and Red Delicious apples, (P > 0.05), but pathogen populations increased in both cultivars (P < 0.05) during storage at 25 degrees C. At 10 degrees C, survival of E. coli O157:H7 was poorest (P < 0.05) in ground Red Delicious apples, while there was no significant difference in survival of E. coli O157:H7 among ground Golden Delicious, Rome, or Winesap cultivars (P > 0.05). When stored at 4 degrees C, Golden Delicious and Rome apples were not statistically different in supporting survival of the pathogen (P > 0.05). In general, apple pH increased during storage and was associated with mold growth. Results of this investigation indicate that there is no trend toward a particular apple cultivar supporting survival of E. coli O157:H7. However, variation in apple pH during storage can negatively or positively influence E. coli O157:H7 survival at 25 degrees C.     

Extension of the thermodynamics of small systems to open metastable states: an example

By using a simplified model of small open liquid-like clusters with surface effects, in the gas phase, it is shown how the statistical thermodynamics of small systems can be extended to include metastable supersaturated gaseous states not too far from the gas-liquid equilibrium transition point. To accomplish this, one has to distinguish between mathematical divergence and physical convergence of the open-system partition function.