Many patients with glioma harbor specific mutations in the isocitrate dehydrogenase gene IDH1 that associate with a relatively better prognosis. IDH1-mutated tumors produce the oncometabolite 2-hydroxyglutarate. Because IDH1 also regulates several pathways leading to lipid synthesis, we hypothesized that IDH1-mutant tumors have an altered phospholipid metabolite profile that would impinge on tumor pathobiology. To investigate this hypothesis, we performed 31 P-MRS imaging in mouse xenograft models of four human gliomas, one of which harbored the IDH1-R132H mutation.31 P-MR spectra from the IDH1-mutant tumor displayed a pattern distinct from that of the three IDH1 wild-type tumors, characterized by decreased levels of phosphoethanolamine and increased levels of glycerophosphocholine. This spectral profile was confirmed by ex vivo analysis of tumor extracts, and it was also observed in human surgical biopsies of IDH1-mutated tumors by 31 P highresolution magic angle spinning spectroscopy. The specificity of this profile for the IDH1-R132H mutation was established by in vitro 31 P-NMR of extracts of cells overexpressing IDH1 or IDH1-R132H. Overall, our results provide evidence that the IDH1-R132H mutation alters phospholipid metabolism in gliomas involving phosphoethanolamine and glycerophosphocholine. These new noninvasive biomarkers can assist in the identification of the mutation and in research toward novel treatments that target aberrant metabolism in IDH1-mutant glioma. Cancer Res; 74(17); 4898-907. Ó2014 AACR.

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A linear code C is said to be a complementary-dual code (an LCDThis paper is to identify few classes of LCD quasi-cyclic (QC) codes. A sufficient condition for a ρ-generator QC code C is given under which C is an LCD code. Another sufficient condition is given for maximal 1-generator codes. We provide two necessary and sufficient conditions for a maximal 1-generator QC code C satisfying certain constraints to be an LCD code. It is shown that unlike cyclic codes, a maximal 1-generator index-2 QC code is reversible if and only if it is a self-dual code. Several classes of LCD QC codes are introduced.

This article reviews the methodological aspects of detecting low-abundant J-coupled metabolites via 1D spectral editing techniques and 2D nuclear magnetic resonance (NMR) methods applied in vivo, in humans, with a focus on the brain. A brief explanation of the basics of J-evolution will be followed by an introduction to 1D spectral editing techniques (e.g., J-difference editing, multiple quantum coherence filtering) and 2D-NMR methods (e.g., correlation spectroscopy, J-resolved spectroscopy). Established and recently developed methods will be discussed and the most commonly edited J-coupled metabolites (e.g., neurotransmitters, antioxidants, onco-markers, and markers for metabolic processes) will be briefly summarized along with their most important applications in neuroscience and clinical diagnosis.

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Studying noninvasively the internal nanoporous structure of a single Tussah silk fiber under different humidity conditions, we demonstrate for the first time the feasibility of in-situ ptychographic tomography. The resulting 3D images of the silk fiber interior, obtained at both dry and humid conditions, yield quantitative information about the spatial density variations in the form of detailed maps of the size, shape, and orientation distributions of the nanopores inside the silk fiber, revealing that the fiber swells anisotropically in humid conditions, with the expansion taking place solely normal to the fiber axis. Exploiting quantitative information on the fiber’s electron density, hydration was found to proceed through interaction with the silk protein rather than filling of pores.

Generating MR-derived growth pattern models for glioblastoma multiforme (GBM) has been an attractive approach in neuro-oncology, suggesting a distinct pattern of lesion spread with a tendency in growing along the white matter (WM) fibre direction for the invasive component. However, the direction of growth is not much studied in vivo. In this study, we sought to study the dominant directions of tumour expansion/shrinkage pre-treatment. We examined fifty-six GBMs at two time-points: at radiological diagnosis and as part of the pre-operative planning, both with contrast-enhanced T1-weighted MRIs. The tumour volumes were semi-automatically segmented. A non-linear registration resulting in a deformation field characterizing the changes between the two time points was used together with the segmented tumours to determine the dominant directions of tumour change. To compute the degree of alignment between tumour growth vectors and WM fibres, an angle map was calculated. Our results demonstrate that tumours tend to grow predominantly along the WM, as evidenced by the dominant vector population with the maximum alignments. Our findings represent a step forward in investigating the hypothesis that tumour cells tend to migrate preferentially along the WM.

Cobalt nanoparticles play an important role as catalysts for the Fischer− Tropsch synthesis, which is an attractive route for production of synthetic fuels. It is of particular interest to understand the varying conversion rate during the first hours after introducing synthesis gas (H 2 and CO) to the system. To this end, several in situ characterization studies have previously been done on both idealized model systems and commercially relevant catalyst nanoparticles, using bulk techniques, such as X-ray powder diffraction and X-ray absorption spectroscopy. Since catalysis takes place at the surface of the cobalt particles, it is important to develop methods to gain surface-specific structural information under realistic processing conditions. We addressed this challenge using small-angle X-ray scattering (SAXS), a technique exploiting the penetrating nature of Xrays to provide information about particle morphology during in situ experiments. Simultaneous wide-angle X-ray scattering was used for monitoring the reduction from oxide to catalytically active metal cobalt, and anomalous SAXS was used for distinguishing the cobalt particles from the other phases present. After introducing the synthesis gas, we found that the slope of the scattered intensity in the Porod region increased significantly, while the scattering invariant remained essentially constant, indicating a change in the shape or surface structure of the particles. Shape-and surface change models are discussed in light of the experimental results, leading to an improved understanding of catalytic nanoparticles. ■ INTRODUCTIONThe Fischer−Tropsch synthesis (FTS) is a set of chemical reactions that forms hydrocarbon chains from a mixture of CO and H 2 . The product can be upgraded to petroleum substitutes, for example synthetic diesel.1 Typical commercial FTS catalysts consist of cobalt nanoparticles of diameter ∼20 nm dispersed on a porous support material, 2 such as γ-alumina. Optimal particle size, temperature, and pressure are required for obtaining high activity and high selectivity to long-chain hydrocarbons. The reaction output is dependent on the temperature and the pressure in the reactor cell; the standard industrial process operates at T ≈ 220°C and pressure of 25− 45 bar, conditions favorable for producing waxes.1 At ambient pressure the CO conversion is still high, but the products are predominantly short molecules, thus tending to remain in the gas phase.The FTS shows an initial stage lasting a few hours where the conversion rate increases to a high level, followed by a much slower decrease of the reaction rate that continues on a time scale of days and months.3 Understanding the mechanisms behind this behavior is of high commercial and academic interest. Tsakoumis et al.3 combined in situ X-ray absorption spectroscopy (XAS) and X-ray powder diffraction to investigate the cobalt catalyst nanoparticles during the FTS synthesis. The deactivation was detected by mass spectrometry, but no apparent changes in the X-ray signal could be...