The hydrolysis of starch is a key factor for controlling the glycemic index (GI). Slow digestion properties of starch lead to slower glucose release and lower glycemic response. Food with high resistant starch (RS) possesses great value for controlling the GI. To elucidate the factors that play a role in slow digestibility, seven rice mutants different in RS contents were selected for comparative studies. The degree of hydrolysis showed highly significant correlation with RS, apparent amylose content (AAC), lipid content (LC), and other starch physiochemical properties in all these materials with different RS contents. The rate of in vitro digestible starch correlated positively with RS, whereas digestibility was affected mostly by lipid content for those mutants with similar RS. Starch-lipid complexes and short chains with degrees of polymerization (DP) of 8-12 strongly influenced starch digestion. The integrity of aggregated starch and the number of round starch granules might influence the digestibility of starch directly.

A hybrid algorithm, combining analytic Kirchhoff approximation (KA) and numerical method of moments (MoMs), is developed to solve the coupling electric-field integral equations (EFIEs) of scattering from a perfect electric conducting (PEC) object above a randomly rough PEC surface under TE-polarized plane-wave incidence. The MoM with the conjugate gradient approach is used to first solve the EFIE of the object. The surface fields on the rough surface are analytically expressed using the KA method, and large memory and computations for those fields are greatly reduced. An iterative approach of the surface fields induced on both object and rough surface is then utilized to take into account interactions between the object and underlying rough surface. Convergence of this hybrid algorithm is numerically validated. Making use of Monte Carlo realization, bistatic scattering from a 2-D PEC cylindrical object above a PEC rough surface is well simulated by this hybrid KA-MoM algorithm.Index Terms-Hybrid algorithm, iteration, Kirchhoff approximation (KA), method of moments (MoMs), object and rough surface.

Low phytic acid grains can provide a solution to dietary micronutrient deficiency and environmental pollution. A low phytic acid 1-1 (lpa1-1) barley mutant was identified using forward genetics and the mutant gene was mapped to chromosome 2HL. Comparative genomic analysis revealed that the lpa1-1 gene was located in the syntenic region of the rice Os-lpa-MH86-1 gene on chromosome 4. The gene ortholog of rice Os-lpa-MH86-1 (designated as HvST) was isolated from barley using polymerase chain reaction and mapped to chromosome 2HL in a doubled haploid population of Clipper×Sahara. The results demonstrate the collinearity between the rice Os-lpa-MH86-1 gene and the barley lpa1-1 region. Sequence analysis of HvST revealed a single base pair substitution (C→T transition) in the last exon of the gene in lpa1-1 (M422), which resulted in a nonsense mutation. These results will facilitate our understanding of the molecular mechanisms controlling the low phytic acid phenotype and assist in the development of a diagnostic marker for the selection of the lpa1-1 gene in barley.