Unidirectional endotaxial cobalt di-silicide nanowires on Si(110) substrates.

Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ∼600 °C produces unidirectional CoSi2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four major types of distinct NWs, all growing along the [-110] in-plane direction except one type growing along the in-plane [-113] direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types-flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi2 and Si are A-type. In the ridged NWs CoSi2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.

Low protein and high-energy diet: a possible natural cause of fatty liver hemorrhagic syndrome in caged White Leghorn laying hens.

Fatty liver hemorrhagic syndrome (FLHS) is a metabolic condition of chicken and other birds caused by diverse nutritional, hormonal, environmental, and metabolic factors. Here we studied the effect of different diet composition on the induction of FLHS in single comb White Leghorn (WL) Hy-line laying hens. Seventy six (76) young WL (26 wks old) laying hens and 69 old hens (84 wks old) of the same breed were each divided into 4 treatment groups and provided 4 different diet treatments. The diet treatments included: control (C), 17.5% CP, 3.5% fat (F); normal protein, high fat (HF), 17.5% CP, 7% F; low protein, normal fat (LP), 13% CP, 3.5% F; and low protein, high fat (LPHF), 13% CP, 6.5% F. The diets containing high fat also had a higher ME of 3,000 kcal/kg of feed while the other 2 diets with normal fat had a regular lower amount of ME (2750 kcal/kg). Hen-day egg production (HDEP), ADFI, BW, egg weight, plasma enzymes indicating liver damage (alkaline phosphatase [ALP], aspartate aminotransferase [AST], gamma-glutamyl transferase [GGT]), liver and abdominal fat weight, liver color score (LCS), liver hemorrhagic score (LHS), liver fat content (LFC), liver histological examination, lipid peroxidation product in the liver, and genes indicating liver inflammation were evaluated. HDEP, ADFI, BW, and egg weight were significantly decreased in the LPHF diet group, while egg weight was also decreased in the LP diet group. In the young hens (LPHF group), ALP was found significantly higher at 30 d of diet treatment and was numerically higher throughout the experiment, while AST was significantly higher at 105 d of treatment. LCS, LHS, and LFC were significantly higher in young hens on the LPHF diet treatment. A liver histological examination shows more lipid vacuolization in the LPHF treatment diet. HF or LP alone had no significant effect on LFC, LHS, or LCS. We suggest that LP in the diet with higher ME from fat can be a possible natural cause for predisposing laying hens to FLHS.

Roughening in electronic growth of Ag on Si(111)-(7×7) surfaces.

Roughening in the electronic growth of Ag films on Si(111)-(7×7) surfaces for a film thickness ranging from 1 to 30 monolayers is reported. Ag films exhibit the growth of flat-top plateaus of preferential heights due quantum electronic effect. We have observed roughening of the film growth due to instability with linear diffusion characterized by the ln(θ)(1/2) dependence of the local surface slope, where θ is the Ag coverage. The roughening of the surface morphology has been characterized by scaling exponents α, ß and 1/z, which are determined using scanning tunneling microscopy. Increased value of α = 0.67 ± 0.04 at the early stage of the electronic growth with two atomic layer height flat-top isolated Ag mounds to 0.77 ± 0.06 at the later stage of the growth when isolated mounds coalesce and form percolated structures maintaining preferential heights of an even number of atomic layers in the Ag mounds indicates the instability in the electronic growth. As a result, interface width W increases as a power law of coverage (θ), W ∼ θ(ß), with growth exponent ß = 0.33 ± 0.03, and lateral correlation length ξ grows as ξ ∼ θ(1/z) with 1/z = 0.27 ± 0.05.