142 research outputs found
Joint Modeling of Longitudinal Imaging and Survival Data
This article considers a joint modeling framework for simultaneously examining the dynamic pattern of longitudinal and ultrahigh-dimensional images and their effects on the survival of interest. A functional mixed effects model is considered to describe the trajectories of longitudinal images. Then, a high-dimensional functional principal component analysis (HD-FPCA) is adopted to extract the principal eigenimages to reduce the ultrahigh dimensionality of imaging data. Finally, a Cox regression model is used to examine the effects of the longitudinal images and other risk factors on the hazard. A theoretical justification shows that a naive two-stage procedure that separately analyzes each part of the joint model produces biased estimation even if the longitudinal images have no measurement error. We develop a Bayesian joint estimation method coupled with efficient Markov chain Monte Carlo sampling schemes to perform statistical inference for the proposed joint model. A Monte Carlo dynamic prediction procedure is proposed to predict the future survival probabilities of subjects given their historical longitudinal images. The proposed model is assessed through extensive simulation studies and an application to Alzheimer’s Disease Neuroimaging Initiative, which turns out to hold the promise of accuracy and possess higher predictive capacity for survival outcome compared with existing methods. Supplementary materials for this article are available online.</p
Nickel-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Cross-Electrophile Coupling of In Situ Generated NHP Esters with Unactivated Alkyl Bromides
The formation of C(sp3)–C(sp3) bonds
by cross-coupling remains a challenge in synthesis. Here, we demonstrate
a two-step, one-pot protocol for the in situ generation of N-hydroxyphthalimide esters and their nickel-catalyzed cross-electrophile
coupling with unactivated alkyl bromides for the construction of 1°/1
° C(sp3)–C(sp3) bonds. The conditions
tolerate an array of functional groups, and mechanistic studies indicate
that both substrates are converted to alkyl radicals during the reaction
ProtRAP: Predicting Lipid Accessibility Together with Solvent Accessibility of Proteins in One Run
Solvent accessibility has been extensively used to characterize
and predict the chemical properties of the surface residues of soluble
proteins. However, there is not yet a widely accepted quantity of
the same dimension for the study of lipid-accessible residues of membrane
proteins. In this study, we propose that lipid accessibility, defined in a similar way to solvent accessibility, can be used
to characterize the lipid-accessible residues of membrane proteins.
Moreover, we developed a deep learning-based method, ProtRAP (Protein
Relative Accessibility Predictor), to predict the relative lipid accessibility
and relative solvent accessibility of residues from a given protein
sequence, which can infer which residues are likely accessible to
lipids, accessible to solvent, or buried in the protein interior in
one run
Impact of carbon cap and carbon credit prices on environmental objective.
Impact of carbon cap and carbon credit prices on environmental objective.</p
Typical Pareto solutions of inventory allocation planning problem.
Typical Pareto solutions of inventory allocation planning problem.</p
Impact of carbon emission.
(A) Environmental cost under different carbon caps. (B) Floating of environmental cost with different carbon credit prices.</p
Results of Taguchi experiments.
(A) SNR graph from the Taguchi experiments. (B) Mean graph from Taguchi experiments.</p
The flow of materials in supplier–manufacturer network.
The flow of materials in supplier–manufacturer network.</p
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