Author
Robert Powers
Other affiliations: Weizmann Institute of Science, National Institutes of Health
Bio: Robert Powers is an academic researcher from University of Nebraska–Lincoln. The author has contributed to research in topics: Metabolomics & Nuclear magnetic resonance spectroscopy. The author has an hindex of 51, co-authored 186 publications receiving 8840 citations. Previous affiliations of Robert Powers include Weizmann Institute of Science & National Institutes of Health.
Papers published on a yearly basis
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31 Dec 2012
TL;DR: The use of multivariate analysis for metabolomics is discussed, as well as common pitfalls and misconceptions, and spectral features contributing most to variation or separation are identified for further analysis.
Abstract: Metabolomics aims to provide a global snapshot of all small-molecule metabolites in cells and biological fluids, free of observational biases inherent to more focused studies of metabolism. However, the staggeringly high information content of such global analyses introduces a challenge of its own; efficiently forming biologically relevant conclusions from any given metabolomics dataset indeed requires specialized forms of data analysis. One approach to finding meaning in metabolomics datasets involves multivariate analysis (MVA) methods such as principal component analysis (PCA) and partial least squares projection to latent structures (PLS), where spectral features contributing most to variation or separation are identified for further analysis. However, as with any mathematical treatment, these methods are not a panacea; this review discusses the use of multivariate analysis for metabolomics, as well as common pitfalls and misconceptions.
946 citations
TL;DR: A new peak-picking algorithm is described which is based on contour diagrams and designed for the automated interpretation of higher dimensional 3D and 4D spectra and ideally suited as a filter for more sophisticated methods.
693 citations
TL;DR: Although currently overshadowed by MS in terms of numbers of compounds resolved, NMR spectroscopy offers advantages both on its own and coupled with MS, and is adept at tracing metabolic pathways and fluxes using isotope labels.
619 citations
Eppley Institute for Research in Cancer and Allied Diseases1, University of Nebraska Medical Center2, University of Nebraska–Lincoln3, University of Texas MD Anderson Cancer Center4, Cornell University5, University of Málaga6, Harvard University7, University of Texas at Dallas8, University of Colorado Denver9, Stony Brook University10, University of Michigan11
TL;DR: A widely prevalent mechanism of resistance to gemcitabine in pancreatic cancer is established, whereby increased glycolytic flux leads to glucose addiction in cancer cells and a corresponding increase in pyrimidine biosynthesis to enhance the intrinsic levels of deoxycytidine triphosphate (dCTP).
331 citations
TL;DR: In this paper, an expert system for determining resonance assignments from NMR spectra of proteins is described, which combines symbolic constraint satisfaction methods with a domain-specific knowledge base to exploit the logical structure of the sequential assignment problem, the specific features of the various NMR experiments, and the expected chemical shift frequencies of different amino acids.
301 citations
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28 Jul 2005
TL;DR: PfPMP1）与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
01 Aug 2000
TL;DR: Assessment of medical technology in the context of commercialization with Bioentrepreneur course, which addresses many issues unique to biomedical products.
Abstract: BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.
4,833 citations
TL;DR: MolProbity is a general-purpose web server offering quality validation for 3D structures of proteins, nucleic acids and complexes that provides detailed all-atom contact analysis of any steric problems within the molecules as well as updated dihedral-angle diagnostics.
Abstract: MolProbity is a general-purpose web server offering quality validation for 3D structures of proteins, nucleic acids and complexes. It provides detailed all-atom contact analysis of any steric problems within the molecules as well as updated dihedral-angle diagnostics, and it can calculate and display the H-bond and van der Waals contacts in the interfaces between components. An integral step in the process is the addition and full optimization of all hydrogen atoms, both polar and nonpolar. New analysis functions have been added for RNA, for interfaces, and for NMR ensembles. Additionally, both the web site and major component programs have been rewritten to improve speed, convenience, clarity and integration with other resources. MolProbity results are reported in multiple forms: as overall numeric scores, as lists or charts of local problems, as downloadable PDB and graphics files, and most notably as informative, manipulable 3D kinemage graphics shown online in the KiNG viewer. This service is available free to all users at http://molprobity.biochem.duke.edu.
3,638 citations
01 Jan 2000
3,536 citations
TL;DR: Current analyses of genetic defects in Drosophila melanogaster, mice, and humans confirm most of these activities in vivo and identify additional processes that involve cell surface heparan sulfate proteoglycans.
Abstract: The heparan sulfate on the surface of all adherent cells modulates the actions of a large number of extracellular ligands. Members of both cell surface heparan sulfate proteoglycan families, the transmembrane syndecans and the glycosylphosphoinositide-linked glypicans, bind these ligands and enhance formation of their receptor-signaling complexes. These heparan sulfate proteoglycans also immobilize and regulate the turnover of ligands that act at the cell surface. The extracellular domains of these proteoglycans can be shed from the cell surface, generating soluble heparan sulfate proteoglycans that can inhibit interactions at the cell surface. Recent analyses of genetic defects in Drosophila melanogaster, mice, and humans confirm most of these activities in vivo and identify additional processes that involve cell surface heparan sulfate proteoglycans. This chapter focuses on the mechanisms underlying these activities and on the cellular functions that they regulate.
2,680 citations