Predictive Thermal Inactivation Model for Effects and Interactions of Temperature, NaCl, Sodium Pyrophosphate, and Sodium Lactate on Listeria monocytogenes in Ground Beef

The effects and interactions of heating temperature (60 °C to 73.9 °C), salt (0.0 % to 4.5 %?w/v), sodium pyrophosphate (0.0 % to 0.5 %?w/v), and sodium lactate (0.0 % to 4.5 %?w/v) on the heat resistance of a five-strain mixture of Listeria monocytogenes in 75 % lean ground beef were examined. Meat samples in sterile filtered stomacher bags were heated in a temperature controlled waterbath to determine thermal death times. The recovery medium was tryptic soy agar supplemented with 0.6 % yeast extract and 1 % sodium pyruvate. Weibull survival functions were employed to model the primary survival curves. Then, survival curve-specific estimated parameter values obtained from the Weibull model were used for determining a secondary model. The results indicate that temperature and salt have a large impact on the inactivation kinetics of L. monocytogenes, while sodium lactate (NaL) has an impact in the presence of salt. The model presented in this paper for predicting inactivation of L. monocytogenes can be used as an aid in designing lethality treatments meant to control the presence of this pathogen in ready-to-eat products.     

Error detection for PHEV,BEV and stationary battery systems

Battery cells being electrically disconnected resulting from degradation, mechanical stress, or corrosion can lead to hazardous situations during operation of electric vehicles or storage systems in stationary applications. The mentioned errors can be acceptable in some cases when cells or cell strings are connected in parallel, but the failure is to be detected in order to guarantee the reliable and safe operation of the battery system. A method enabling the estimation whether individual battery cells are faulty (cell error or electrically disconnected) by evaluating the mean impedance and capacity information of cell groups is introduced and validated.     

Repurposing the Pummerer Rearrangement: Determination of Methionine Sulfoxides in Peptides

The reversible oxidation of methionine residues in proteins has emerged as a biologically important post-translational modification. However, detection and quantitation of methionine sulfoxide in proteins is difficult. Our aim is to develop a method for specifically derivatizing methionine sulfoxide residues. We report a Pummerer rearrangement of methionine sulfoxide treated sequentially with trimethylsilyl chloride and then 2-mercaptoimidazole or pyridine-2-thiol to produce a dithioacetal product. This derivative is stable to standard mass spectrometry conditions, and its formation identified oxidized methionine residues. The scope and requirements of dithioacetal formation are reported for methionine sulfoxide and model substrates. The reaction intermediates have been investigated by computational techniques and by ¹³C NMR spectroscopy. These provide evidence for an α-chlorinated intermediate. The derivatization allows for detection and quantitation of methionine sulfoxide in proteins by mass spectrometry and potentially by immunochemical methods.     

Cognitive Mapping and Planning for Visual Navigation

International Journal of Computer Vision - We introduce a neural architecture for navigation in novel environments. Our proposed architecture learns to map from first-person views and plans a...     

Exploring Social Norms as a Group‐Level Phenomenon: Do Political Participation Norms Exist and Influence Political Participation on College Campuses?

This research explores the relationship between campus political norms and student political participation. This study conceptualizes norms as a group‐level construct by collecting data at several universities (k = 32 universities, n = 1,389 students) where norms vary without campaign intervention. Multilevel modeling reveals that perceptions of political norms converge within universities. Further, frequency of political communication at the group‐ and individual‐level explains increases in normative perceptions. This increase is meaningful because norms at the group level were predictive of political behaviors at the individual level. This research documents the existence of political norms beyond the individual level of analysis and highlights the important role of political norms, political communication, and social context in understanding political participation.     

THE TWO-MESSAGE PROBLEM IN CIPHER TEXT AUTOKEY. PART II

This is Part II of a two-part paper on the problem of the title. In this part the analysis of the two-message problem started in Part I is completed. In addition a brief discussion is given of a computer-assisted solution. A list of twelve two-message problems involving several types of conditions is attached for the benefit of the reader.     

APPLICATIONS OF THE DRAZIN INVERSE TO THE HILL CRYPTOGRAPHIC SYSTEM. PART III.

In this part it is shown how the scalar unit coefficient a appearing in the W key formula (see Part I) can be replaced by an invertible matrix coefficient Γ. (A similar discussion with respect to the V key will appear In Part IV.) Various examples illustrate in detail the different procedures involved. Some examples in the encipherment and decipherment calculations are left as problems for the reader. The Appendix contains a proof of the main theorem.