30 research outputs found
Cenozoic drainage evolution of the Rio Grande paleoriver recorded in detrital zircons in South Texas
<p>Sediment provenance in the lower reach of rivers is important in reconstructing paleogeography and linking continental tectonic and climate changes with sedimentation in continental margins. This study presents 1300 new detrital zircon U–Pb ages from seven latest Eocene–Miocene sandstone and one modern river sand samples in south Texas and integrates these new data with published detrital zircon data to elucidate the evolution of the Rio Grande paleoriver during the Cenozoic. The new data contain a major population of the Cordillera magmatic province (22–280 Ma) and populations older than 280 Ma that were mostly recycled from sedimentary cover in the southern Rocky Mountains and southern Great Plains. The latest Eocene–Oligocene sandstones contain abundant air-fall zircons, and their detrital zircon maximum depositional ages constrain depositional ages. The changes in detrital zircon age distributions suggest that the paleoriver has changed its drainage extent three times, including a late Eocene drainage reduction by cutting off sediment supply from the west, a late Oligocene drainage reduction to the east of the southern Rocky Mountains and expansion to the East Mexico Arc in northeastern Mexico, and a latest Neogene drainage expansion to the west of the Rio Grande Rift and southern Colorado.</p
La Charente
09 mars 18861886/03/09 (A15,N5499)-1886/03/09.Appartient à l’ensemble documentaire : PoitouCh
In Situ Cellulose Nanocrystal-Reinforced Glycerol-Based Biopolyester for Enhancing Poly(lactic acid) Biocomposites
Biobased, elastomeric
polymer poly(glycerol succinate-<i>co</i>-maleate) (PGSMA)
was produced using a “green” synthesis
with added cellulose nanocrystals (CNCs) to create a novel PGSMA–CNC
material. PGSMA–CNC was synthesized with the aim of developing
a new strategy for successfully dispersing CNCs within a poly(lactic
acid) (PLA) matrix for optimal reinforcement of tensile strength and
modulus while having the added benefit of the proven toughness enhancements
of PLA/PGSMA blends. Optical microscopy and fractionation in tetrahydrofuran
showed that CNCs agglomerated during PGSMA–CNC synthesis and
remained in agglomerates during PLA/PGSMA–CNC reactive blending.
Fourier transform infrared, differential scanning calorimetry, and
dynamic mechanical analyses also showed that PGSMA–CNC inhibited
the formation of PGSMA crosslinks and PLA-<i>g</i>-PGSMA
during reactive blending. These two effects resulted in loss of impact
strength and only a 4% increase in tensile modulus over PLA/PGSMA
at the highest CNC content. Further work in preventing CNC aggregation
could help improve mechanical properties of the final blend
Additional file 5: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
A transcript profile comparison to evaluate purity of pollen samples used for RNA-Seq. A subset of 12 genes was used to compare relative purities of pollen samples in the current pollen transcriptome study to those from a RNA-Seq study from Loraine et al. [22] (yellow highlights) or a microarray experiment from Qin et al. 2009 [23] (purple highlights). Four references genes were chosen to generate normalization factors that could be used to adjust expression values in Loraine et al. [22] and Qin et al. 2009 [23] to allow a relative comparison of the three data sets for WT pollen under control (normal) conditions. For a control group, three CNGC genes were chosen that displayed low to moderate levels of expression (Tunc-Ozdemir et al. 2013 [24] and Frietsch et al. 2007 [25]). As markers for potential contamination from photosynthetic tissues, five different nuclear encoded genes were chosen that are associated with either photosystems I/II, or chlorophyll A-B binding proteins (Umate 2010 [26]). Average relative ratios are shown for each of the four different pollen samples in comparison to both Loraine et al. [22] and Qin et al. [23]. (XLSX 19 kb
Additional file 3: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
Normalized transcript expression counts for WT and cngc16 pollen with and without HS. Expression counts from Additional file 2 were subjected to exclusions/filters and normalized as described in methods. Expression data from other transcriptome studies (microarray and RNA-Seq) were added to the table for comparisons. These included an RNA-Seq data set for WT pollen and seedlings from Loraine et al. 2013 (PMCID: PMC3668042 [22]), two pollen microarray experiments from Qin et al. 2009 (PMCID: PMC2726614 [23]) and Borges et al. 2008 (PMCID: PMC2556834 [72]), and finally HS seedlings from Schmid et al. 2005 (PMID:15806101 [33]), respectively. Ratios of expression between pollen and seedling are based on Loraine et al. 2013 (PMCID: PMC3668042 [22]). In cases where the seedling value was below the limit of detection, a minimal value of 0.0019 was substituted in its place as a denominator (0.0019 was the RPKM for ATCG00860 and was the lowest value reported in Loraine et al. 2013 (PMCID: PMC3668042 [22]). Ratio of expression between semi-in vivo pollen tube over dry pollen is based on Qin et al. 2009 (PMCID: PMC2726614 [23]). HS dependent changes in transcript abundance in shoots were based on publicly available data using the AtGenExpress Visualization Tool (AVT) ( http://jsp.weigelworld.org/expviz/expviz.jsp , Schmid et al. 2005 (PMID:15806101 [33] for seedlings exposed to one hour HS at 38 °C). The log2-fold change was calculated based on a comparison of means of normalized values for two heat-stressed and two non-stressed seedling samples. NA stands for not available. Not Calculated, refers to a value not being calculated because one of the input sample read counts was considered to have an extreme outlier (see AT2G42540 and ATMG01360). (XLSX 8952 kb
Additional file 1: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
Hot/Cold stress cycle. Diagram showing the Hot/Cold stress-cycle used here for growing plants from which pollen samples for RNA-Seq experiment were harvested at the end of HS-peak at 40 °C. See Methods and [20] for more details. (PPTX 50 kb
Additional file 13: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
A comparison of HS-dependent changes in pollen to 67 multi-stress response genes in vegetative tissues. From a list of 67 multi-stress genes curated by Swindell 2006 (PMCID: PMC1698639 [47]; highlighted in purple), 19 genes showed detectable expression in pollen. Among those, only three genes showed significant changes in pollen HS (red font). (XLSX 596 kb
Additional file 7: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
RNA-Seq validation using real-time Q-PCR. a. Comparison of expression values obtained from Q-PCR and RNA-Seq normalized to WT control (normal). The analysis was performed on two different reference genes separately (CYCP2 (AT3G21870) and UBQ7 (AT2G35635)). b. Primer sequences used for real-time Q-PCR. (XLSX 16 kb
Additional file 4: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
Library size and principal component analysis. a. Table showing library sizes of each sample. b. A principal component analysis (PCA) of the filtered data showing that 87% of the variance of the samples can be explained by differences in the stress states. See methods for more details. Control and heat correspond to normal and HS conditions, respectively. (PPTX 43 kb
Additional file 15: of A comparison of heat-stress transcriptome changes between wild-type Arabidopsis pollen and a heat-sensitive mutant harboring a knockout of cyclic nucleotide-gated cation channel 16 (cngc16)
GO analysis on the 192 largest differences between WT and cngc16 under HS. A GO analysis pie chart is shown for Molecular Function (a), Cellular Component (b), and Biological Process (c) generated using an upload of Additional file 3 or Additional file 9e column R listing the differences (≥ 2-fold and adjusted p-value ≤0.01) between WT and cngc16 HS-transcriptomes. Categories were defined using PANTHER Overrepresentation Test (release 2017–04-13 [61]) using a GO Ontology database (released 2017–08-14) with 27,060 reference genes for Arabidopsis thaliana. Gene categories shown displayed enrichments with a p-value of ≤0.05. (PPTX 993 kb