Analysis of expressed sequence tag loci on wheat chromosome group 4

A total of 1918 loci, detected by the hybridization of 938 expressed sequence tag unigenes (ESTs) from 26 Triticeae cDNA libraries, were mapped to wheat (Triticum aestivum L.) homoeologous group 4 chromosomes using a set of deletion, ditelosomic, and nulli-tetrasomic lines. The 1918 EST loci were not distributed uniformly among the three group 4 chromosomes; 41, 28, and 31% mapped to chromosomes 4A, 4B, and 4D, respectively. This pattern is in contrast to the cumulative results of EST mapping in all homoeologous groups, as reported elsewhere, that found the highest proportion of loci mapped to the B genome. Sixty-five percent of these 1918 loci mapped to the long arms of homoeologous group 4 chromosomes, while 35% mapped to the short arms. The distal regions of chromosome arms showed higher numbers of loci than the proximal regions, with the exception of 4DL. This study confirmed the complex structure of chromosome 4A that contains two reciprocal translocations and two inversions, previously identified. An additional inversion in the centromeric region of 4A was revealed. A consensus map for homoeologous group 4 was developed from 119 ESTs unique to group 4. Forty-nine percent of these ESTs were found to be homoeologous to sequences on rice chromosome 3, 12% had matches with sequences on other rice chromosomes, and 39% had no matches with rice sequences at all. Limited homology (only 26 of the 119 consensus ESTs) was found between wheat ESTs on homoeologous group 4 and the Arabidopsis genome. Forty-two percent of the homoeologous group 4 ESTs could be classified into functional categories on the basis of blastX searches against all protein databases.

Physical properties and composition of femurs of rat fed with diets based on corn tortillas made from different processes

In this study the effect of calcium absorption on some physical properties and composition of rat femurs was evaluated, comparing rats fed with raw whole corn (RC), tortillas made from extruded masa with 0.25% lime content (TEWL) and without lime (TE), and nixtamal tortillas (NT). The diets were formulated to contain the same amount of protein, oil, fiber, vitamins and minerals other than calcium. In all diets 0.20% calcium was added. At the end of the trials, the femurs were extracted, weighed and measured for ash, calcium and phosphorus content, some physical dimensions, and the crystallinity percentage. The femurs of rats fed with TEWL and NT were heavier, thicker, longer and had higher calcium content. On the other hand, the force required to break the femur of rats fed on ETWL and NT was 1.25 kg greater than that required to break the femurs of rats fed with RC. Higher crystallinity percentage values were observed in the femurs of the rats fed with NT (37.66%) and TEWL (36.98%) as compared to a 30.31% value obtained with the RC.

The Structure of W/C (0.15 < γ < 0.8) Multilayers Annealed in Argon or Air

We report the effect that thermal annealing in inert and oxidizing atmospheres, and with and without encapsulating layers, has on the structure of tungsten/carbon [W/C] multilayer thin films. This study focuses on the tungsten component and deals mainly with multilayers where the ratio of thickness of tungsten layers is equal to or greater than for the carbon layers (that is, γ ≤ 0.5). This is in contrast to prior studies where the tungsten layer thickness was generally held constant and the carbon layer was varied. Thermal annealing in inert atmospheres produces reactions and other structural changes in the tungsten and carbide layers which depend on the as-deposited multilayer structure which depends, in turn, on the thickness of the tungsten layer. In samples where both the tungsten and carbide fractions of the multilayer are completely amorphous as deposited, which is the case for thin tungsten layers (thickness of tungsten (tw) < 4 nm/period), the reactions in the tungsten layer forming crystalline tungsten and tungsten carbide occur at annealing temperatures above 900°C. The layer pair spacing, or period, (d), in this group shows an expansion of up to 10-15% of the original value as has been reported in the past. Changes in both the tungsten and carbide layers, and their interfaces, contribute to changes in d spacing and relative thickness of the high and low Z components. When the tungsten layer thickness exceeds 4 nm per period the tungsten is partially crystallized in as-prepared samples. In such multilayers interfacial reactions, producing an oriented partially crystalline W2C/C superlattice, occur at temperatures of 600°C and below. The fact that W2C crystallites in one period can form a structure which is correlated to W2C crystallites in neighboring layers is somewhat surprising, since layers are presumably still separated by amorphous carbon which is still visible via Raman. The expansion of the layer pair spacing is relatively small (<5%) in this group and, more importantly, mostly involves increases in the thickness of the high Z components. Samples annealed in air at temperatures below 300°C are progressively destroyed by the oxidation of both tungsten and carbide layers. Encapsulation of similar multilayers with a thin (30 nm) dielectric layer of any of several types can retard oxidation to 600°C. The silicon-containing encapsulants generally perform better. Failure at this temperature is seen to occur from pinhole formation.