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Quantum-connectivity indices are topographic descriptors combining quantum-chemical and topological information. They are used to describe the water solubility of a noncongeneric data set of organic compounds. A QSPR model is obtained with two quantum-connectivity indices that accounts for more than 90% of the variance in the water solubility of these(More)
Randomly selected New York steaks from domestic and imported beef were purchased in three major Mexican cities, comparing Mexican beef (from northern, central, and southern regions of the country) and American beef (USDA-Choice and ungraded No Roll). The meat was analyzed for chemical composition, Warner-Bratzler shear force (WBSF), cooking loss, color and(More)
The objective of the present study was to evaluate quality and yield attributes of Mexican beef carcasses to serve as a benchmark for production in the Mexican beef cattle industry. Seven packing plants were surveyed nationwide. Carcass yield and quality traits were assessed in the cooler at approximately 24 h postmortem. Results indicated that around 90%(More)
Acetohydroxyacid synthase (AHAS) is a thiamin diphosphate dependent enzyme that catalyses the decarboxylation of pyruvate to yield the hydroxyethyl-thiamin diphosphate (ThDP) anion/enamine intermediate (HEThDP(-)). This intermediate reacts with a second ketoacid to form acetolactate or acetohydroxybutyrate as products. Whereas the mechanism involved in the(More)
A quantitative structure-property relationship (QSPR) model is developed to predict the logarithm of the soil sorption coefficient of 82 organic compounds. The data set contains polar and nonpolar, saturated, unsaturated, aliphatic, aromatic, and polycyclic aromatic compounds covering a log K(oc) range from about 1 to 6 log units. The best correlation(More)
The goal of this article is to stress the importance of considering the phase in QSPR studies. It is found that the phase plays a fundamental role in the QSPR models from both a statistical and a physical point of view. From a statistical point of view, it is observed that the predictive performance drops drastically when the QSPR model, obtained for a(More)
Beef forequarter muscles biceps brachii (BRB), brachialis (BRA), complexus (COM), splenius (SPL), infraspinatus (INF), teres major (TER), rhomboideus (RHO), subscapularis (SUB), supraspinatus (SUP), triceps brachii long-head (TRB) and triceps brachii lateral-head (TRI) were obtained from Mexican beef carcasses originated from Bos indicus (Bi, n=10) or Bos(More)
The Henry's law constants for all 12 polychlorinated benzene congeners were calculated using semiempirical quantum chemical solvation models (SM2, SM2.1, and SM3), and their performances are discussed. The values obtained by the SM3 method are underestimated compared with the experimental values and those calculated by SM2 and SM2.1 methods. This(More)
Quantitative structure-property relationship (QSPR) models are developed to predict the logarithm of infinite dilution activity coefficient of hydrocarbons, oxygen containing organic compounds and halogenated hydrocarbons in water at 298.15 K. The description of the molecular structure in terms of quantum-connectivity descriptors allows to obtain more(More)
The Henry's law constants (H) for triazine derived herbicides are calculated using quantum chemical solvation models, SM2, SM3, PCM-DFT, and CPCM-DFT, and their performances are discussed. The results show considerable differences in performance among the different levels of theory. The values of H calculated by the semiempirical methods agree much better(More)