Rice, one of the world's most important food plants, has important syntenic relationships with the other cereal species and is a model plant for the grasses. Here we present a map-based, finished quality sequence that covers 95% of the 389 Mb genome, including virtually all of the euchromatin and two complete centromeres. A total of 37,544 nontransposable-element-related protein-coding genes were identified, of which 71% had a putative homologue in Arabidopsis. In a reciprocal analysis, 90% of the Arabidopsis proteins had a putative homologue in the predicted rice proteome. Twenty-nine per cent of the 37,544 predicted genes appear in clustered gene families. The number and classes of transposable elements found in the rice genome are consistent with the expansion of syntenic regions in the maize and sorghum genomes. We find evidence for widespread and recurrent gene transfer from the organelles to the nuclear chromosomes. The map-based sequence has proven useful for the identification of genes underlying agronomic traits. The additional single-nucleotide polymorphisms and simple sequence repeats identified in our study should accelerate improvements in rice production.

A transparent flame‐retardant unsaturated polyester resin (FR‐UPR) was obtained by reacting propylene glycol (PG) with maleic anhydride (MA), phthalic anhydride (PA), and 9,10‐dihydro‐10[2,3‐di(hydroxy carbonyl)propyl]‐10‐phosphaphenanthrene‐10‐oxide (DDP) synthesized from 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) and itaconic acid (ITA). The chemical structure of the resulting FR‐UPR was confirmed by FTIR, 1H‐NMR and 31P‐NMR. The average molecular weight and viscosity of the FR‐UPR were determined by gel permeation chromatography (GPC) and viscometer, respectively. Thermal stability was studied by thermogravimetric analysis (TGA) both in air and nitrogen to determine the thermal decomposition mechanism, and the apparent activation energy (Ea) was calculated by both the Kissinger and Ozawa methods. Compared to unsaturated polyester resin (UPR), the higher Ea of FR‐UPR3 implied an improved thermal stability. According to variations of the limited oxygen index (LOI) values, the UL 94 rating of vertical burning test and scanning electron microscopy (SEM) photographs of char residues, the flame retardance of cured FR‐UPR was enhanced with increasing DDP content. The study of fire reaction tests, using a cone calorimeter, suggested that there was a significant reduction of flammability in the FR‐UPR. Copyright © 2010 John Wiley & Sons, Ltd.

The strong interchain packing and polarity of polyimide (PI) compromise its outstanding thermal and mechanical properties. Crown ethers are theoretically expected to form host–guest inclusion complex with PI and improve its disadvantages. On the basis of this hypothesis, we synthesized a series of PI/crown ether composite films and investigated their synthesis mechanism, structures and properties. Our results suggest that the introduction of crown ethers increased the free volume of PI matrix and generated a special necklace-like supramolecular structure, which simultaneously and greatly improved PI’s mechanical, dielectric and hydrophobic properties. The Young modulus, elongation and tensile energy at break of PI composite films were maximally increased by 73.0%, 135.5%, and 190.0%, respectively. Meanwhile their dielectric constant and water absorption were minimized by 16.6% and 66.8%, respectively. Crown ethers with different molecular sizes demonstrated different improvement effects on PI’s properties. Their inclusion rates stabilized at ∼50%, which are related to the equal reaction probability between anhydride and amino groups.

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