Axelsen Cullen (parentsphere14)

While some acyl thioesterases produce fatty acids that clearly play roles in plant-insect or plant-microbial interactions, most plant acyl thioesterases have yet to be fully characterized both in terms of their substrate specificities and their functions. click here The biotechnological applications of plant acyl thioesterases and synthetases are also discussed, as there is significant interest in these enzymes as catalysts for the sustainable production of fatty acids and their derivatives for industrial uses. © 2020 AOCS.Clinical studies of predictive diagnostic tests consider the evaluation of a single test and comparison of two tests regarding their predictive accuracy of disease status. The positive predictive value (PPV) curve is used for assessing the probability of predicting the disease given a positive test result. The sequential property of one PPV curve had been studied. However, in later stages of diagnostic test development, it is more interesting to compare predictive accuracy of two tests. In this article, we propose a group sequential test for the comparison of PPV curves for paired designs when both diagnostic tests are applied to the same subject. We first derive asymptotic properties of the sequential differences of two correlated empirical PPV curves under the common case-control sampling. We then apply these results to develop a group sequential test procedure. The asymptotic results are also critical for deriving both the optimal sample size ratio and minimal required sample sizes for the proposed procedure. Our simulation studies show that the proposed sequential testing maintains the nominal type I error rate in finite samples. The proposed design is illustrated in a hypothetical lung cancer predictive trial and in a cancer diagnostic trial. © 2020 John Wiley & Sons, Ltd.Mediation analyses can help us to understand the biological mechanism in which an exposure or treatment affects an outcome. Single mediator analyses have been used in various applications, but may not be appropriate for analyzing intricate mechanisms involving multiple mediators that affect each other. Thus, in this article, we studied multiple sequentially ordered mediators for a dichotomous outcome and presented the identifiability assumptions for the path-specific effects on the outcome, that is, the effect of an exposure on the outcome mediated by a specific set of mediators. We proposed a closed-form estimator for the path-specific effects by modeling the dichotomous outcome using a probit model. Asymptotic variance of the proposed estimator is derived and can be approximated via delta method or bootstrapping. Simulations under a finite sample showed the validity of our method in capturing the path-specific effects when the probability of each potential counterfactual outcome is not small and demonstrated the utility of a computationally efficient alternative to bootstrapping for calculating variance. The method is applied to investigate the effects of polycystic ovarian syndrome on live birth rates mediated by estradiol levels and the number of oocytes retrieved in a large electronic in vitro fertilization database. We implemented the method into an R package SOMM, which is available at https//github.com/roqe/SOMM. © 2020 John Wiley & Sons, Ltd.Beer's empiric law states that absorbance is linearly proportional to the concentration. Based on electromagnetic theory, an approximately linear dependence can only be confirmed for comparably weak oscillators. For stronger oscillators the proportionality constant, the molar attenuation coefficient, is modulated by the inverse index of refraction, which is itself a function of concentration. For comparably weak oscillators, the index of refraction function depends, like absorbance, linearly on concentration. For stronger oscillators, this linearity is lost, except at wavenumbers considerably lower than the oscillator position. In these transparency regions, linearity between t