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Improved Correlation (improved + correlation)
Selected AbstractsImproved Correlation Between Sensory and Instrumental Measurement of Peanut Butter TextureJOURNAL OF FOOD SCIENCE, Issue 5 2002C.M. Lee And Two commercial peanut butters and 3 laboratory-prepared peanut butters containing 0.5, 1.5 and 2.5% stabilizer were evaluated by sensory and instrumental texture profile analysis (TPA) using an Instron. A 2×3 factorial design consisting of crosshead speeds of 5 and 50 mm/min, and amount and type of fluid added was used. A descriptive panel (n= 11) was used to evaluate 14 sensory TPA attributes. Twelve sensory TPA attributes, compared with only 2 found by other researchers, were highly correlated ( 0.88) with 1 or more instrumental TPA parameters. Prediction models (R 0.71) developed successfully predicted 12 sensory texture attributes from instrumental TPA results. Eleven models, excluding surface roughness, were successfully verified with 0.74 to 7.21% error. [source] Identifying native-like protein structures using physics-based potentialsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 1 2002Brian N. Dominy Abstract As the field of structural genomics matures, new methods will be required that can accurately and rapidly distinguish reliable structure predictions from those that are more dubious. We present a method based on the CHARMM gas phase implicit hydrogen force field in conjunction with a generalized Born implicit solvation term that allows one to make such discrimination. We begin by analyzing pairs of threaded structures from the EMBL database, and find that it is possible to identify the misfolded structures with over 90% accuracy. Further, we find that misfolded states are generally favored by the solvation term due to the mispairing of favorable intramolecular ionic contacts. We also examine 29 sets of 29 misfolded globin sequences from Levitt's "Decoys ,R' Us" database generated using a sequence homology-based method. Again, we find that discrimination is possible with approximately 90% accuracy. Also, even in these less distorted structures, mispairing of ionic contacts results in a more favorable solvation energy for misfolded states. This is also found to be the case for collapsed, partially folded conformations of CspA and protein G taken from folding free energy calculations. We also find that the inclusion of the generalized Born solvation term, in postprocess energy evaluation, improves the correlation between structural similarity and energy in the globin database. This significantly improves the reliability of the hypothesis that more energetically favorable structures are also more similar to the native conformation. Additionally, we examine seven extensive collections of misfolded structures created by Park and Levitt using a four-state reduced model also contained in the "Decoys ,R' Us" database. Results from these large databases confirm those obtained in the EMBL and misfolded globin databases concerning predictive accuracy, the energetic advantage of misfolded proteins regarding the solvation component, and the improved correlation between energy and structural similarity due to implicit solvation. Z-scores computed for these databases are improved by including the generalized Born implicit solvation term, and are found to be comparable to trained and knowledge-based scoring functions. Finally, we briefly explore the dynamic behavior of a misfolded protein relative to properly folded conformations. We demonstrate that the misfolded conformation diverges quickly from its initial structure while the properly folded states remain stable. Proteins in this study are shown to be more stable than their misfolded counterparts and readily identified based on energetic as well as dynamic criteria. In summary, we demonstrate the utility of physics-based force fields in identifying native-like conformations in a variety of preconstructed structural databases. The details of this discrimination are shown to be dependent on the construction of the structural database. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 147,160, 2002 [source] Retention of arsenic species on zwitterionic stationary phase in hydrophilic interaction chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2010Dan Xie Abstract Zwitterionic hydrophilic interaction chromatography (ZIC® -HILIC) was used to study the retention of selected organoarsenicals. The retention behavior of nine organic arsenic species on ZIC® -HILIC was investigated to elucidate which is the driving force for their separation, hydrophilic partitioning or adsorption driven by hydrogen bonds with surface H-donor/acceptor groups of the stationary phase. For this, the retention factor of the compounds k was correlated with log PO/W and with the calculated strength of hydrogen bonding of the analytes. By examining aliphatic and phenylic compounds separately, improved correlation was received. This indicates that both phenomena contribute to the separation of these arsenic species on ZIC® -HILIC. The results obtained evidence that considerable electrostatic interactions also occur on ZIC® -HILIC. Retention behavior of arsenic species was investigated by varying the separation conditions, which shows that the composition of the eluent has a strong influence on the retention behavior. It is highly dependent on water/acetonitrile ratio, pH value and salt additives. Dissociation degree and polarity of arsenic species, which are varying with pH, regulate the distribution of arsenic species between stationary and mobile phases in HILIC. Increase in the ammonium acetate concentration leads to shortened or to prolonged retention depending on the structure of the arsenic species. [source] Development of a new wind-rose for the British Isles using radiosonde data, and application to an atmospheric transport modelTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 621 2006A. J. Dore Abstract A six-hourly dataset of radiosonde ascents spanning a ten-year period from four stations in the British Isles has been used to generate a set of wind frequency roses and wind speed roses for the pressure level range 950,900 hPa. The wind frequency rose showed close agreement with the long-term series of the Jenkinson classification scheme. Small but significant inter-station and interannual variations were observed. Seasonal analysis of the data revealed the higher incidence of north-easterlies during spring months whilst the stronger wind speeds associated with the winter months were also evident. The use of a harmonic mean was found to be appropriate for calculating a directionally dependent wind speed for use in an atmospheric transport model. A harmonic mean wind speed value of 7.5 m s,1 was generated from the entire dataset, the same as that which has previously been used in other transport models. This is also the same value as the ,optimized wind speed' that was generated by Singles et al. The radiosonde wind frequency rose and wind speed rose were input to the FRAME atmospheric transport model. This resulted in an improved correlation with measurements of SO2 concentrations from a national monitoring network when compared to a model simulation using the earlier dataset of Jones. Copyright © 2006 Royal Meteorological Society [source] | ||||||||||