5 research outputs found

    Ample weil divisors

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    We define and study positivity (nefness, amplitude, bigness and pseudo-effectiveness) for Weil divisors on normal projective varieties. We prove various characterizations, vanishing and non-vanishing theorems for cohomology, global generations statements, and a result related to log Fano

    Improved Sphingolipidomic Approach Based on Ultra-High Performance Liquid Chromatography and Multiple Mass Spectrometries with Application to Cellular Neurotoxicity

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    The emerging field of sphingolipidomics calls for accurate quantitative analyses of sphingolipidome. Existing analytical methods for sphingolipid (SPL) profiling often suffer from isotopic/isomeric interference, leading to the low-abundance, but biologically important SPLs being undetected. In the current study, we have developed an improved sphingolipidomic approach for reliable and sensitive quantification of up to 10 subclasses of cellular SPLs. By integratively utilizing high efficiency chromatographic separation, quadrupole time-of-flight (Q-TOF) and triple quadrupole (QQQ) mass spectrometry (MS), our approach facilitated unambiguous identification of several groups of potentially important but low-abundance SPLs that are usually masked by isotopic/isomeric species and hence largely overlooked in many published methods. The methodology, which featured a modified sample preparation and optimized MS parameters, permitted the measurement of 86 individual SPLs in PC12 cells in a single run, demonstrating great potential for high throughput analysis. The improved characterization, along with increased sensitivity for low-abundance SPL species, resulted in the highest number of SPLs being quantified in a single run in PC12 cells. The improved method was fully validated and applied to a lipidomic study of PC12 cell samples with or without amyloid β peptide (Aβ) treatment, which presents a most precise and genuine sphingolipidomic profile of the PC12 cell line. The adoption of the metabolomics protocol, as described in this study, could avoid misidentification and bias in the measurement of the analytically challenging low-abundance endogenous SPLs, hence achieving informative and reliable sphingolipidomics data relevant to discovery of potential SPL biomarkers for Aβ-induced neurotoxicity and neurodegenerative disease

    Differentially expressed isoforms (as predicted by LongSAGE tag positions) for the transcript (see text)

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    The tag sequence at position 9 results in the loss of the 3' UTR region targeted by evolutionarily conserved miRNAs. Putative miRNA target sites were predicted using miRanda [34] and are represented by hashed boxes.<p><b>Copyright information:</b></p><p>Taken from "LongSAGE profiling of nine human embryonic stem cell lines"</p><p>http://genomebiology.com/2007/8/6/R113</p><p>Genome Biology 2007;8(6):R113-R113.</p><p>Published online 14 Jun 2007</p><p>PMCID:PMC2394759.</p><p></p

    Expression of selected transcripts during embryoid body differentiation

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    qPCR was used to monitor expression of selected transcripts in ESCs stimulated to differentiate into embryoid bodies. Three control markers, Oct4, Lin28 and Msx1, were included. Expression levels are reported as the mean of triplicate measurements and are normalized to GAPDH.<p><b>Copyright information:</b></p><p>Taken from "LongSAGE profiling of nine human embryonic stem cell lines"</p><p>http://genomebiology.com/2007/8/6/R113</p><p>Genome Biology 2007;8(6):R113-R113.</p><p>Published online 14 Jun 2007</p><p>PMCID:PMC2394759.</p><p></p
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