Mechanical, electronic and stability properties of multi-walled beryllium oxide nanotubes and nanopeapods: a density functional theory study.

Single-, double-, and triple-walled beryllium oxide nanotubes (BeONTs) along with BeO nanopeapods were simulated and geometrically optimized under the density functional theory (DFT) framework to investigate their Young's modulus, electronic properties, and stability. We found better properties in single-walled nanotubes, either their electronic or mechanical properties, than other mentioned nanotubes. Increase in the radius and inter-wall distance made an overall decrease in the Young's modulus of SW and DW BeONTs. The highest obtained modulus of SWBeONTs and DWBeONTS was calculated for structures (14,0) and (8,0)@(14,0) with the magnitudes of 700.12 Gpa and 712.24 Gpa, respectively. In addition, increasing the wall number from one to two resulted to significant growth in Young's modulus of DWBeONTs while created no significant difference between DWBeONTs and TWBeONTs. Bandgap energy of single-walled nanotubes was higher than those of double- and triple-walled nanotubes, and the bandgap showed consistent soar in both SW and DW BeONTs via increase in the radius and inter-wall distance, respectively. Furthermore, considering nanopeapods with various interlayer distances revealed that the Young's modulus and energy gap behavior of these structures were similar to what we observed in SWBeONTs. However, nanopeapods showed weaker mechanical and semiconducting properties compared with SWBeONTs. Moreover, calculating the formation energies of all under consideration structures revealed a reduction of formation energy via an increase in the dimension of single-walled nanotubes, an increase in the dimension of nanotubes via adding more walls, and an increase in the dimension of peapod structures as well, and the bigger structures are more stable than smaller ones.

Comparative effects of zinc-nano complexes, zinc-sulphate and zinc-methionine on performance in broiler chickens.

Micronutrients, especially zinc, have an important role in normal metabolism and growth of broilers. Using novel technologies helps to synthesise novel zinc complexes to deliver this micronutrient more efficiently. In the present study, the effects of different zinc complexes and nano complexes on broiler performance were compared. Broilers in 6 groups were given basal diet (without zinc) and basal diet supplemented with zinc-sulphate, zinc-methionine, zinc-nano-sulphate, zinc-nano-methionine and zinc-nano-max (that was synthesised based on nanochelating technology) at a concentration of 80 mg/kg of diet. At 1-42 d of age, dietary zinc-nano-sulphate supplementation decreased weight gain and feed intake. However, feed conversion ratio was not influenced by treatments. Carcass yield (%) of birds in the zinc-nano-sulphate and control groups were dramatically reduced at 42 d of age and abdominal fat (%) increased in these groups. Relative to the control group, the antibody titre, spleen and bursa of Fabricius (%) were significantly higher in groups supplemented with zinc. Heterophil (%) was also significantly higher in the zinc-nano-methionine group in blood on d 42 compared to the control, zinc-sulphate and zinc-nano-sulphate. Compared to the controls, the mean malondialdehyde content in thigh tissue was significantly reduced in groups supplemented with zinc at the time 0, 50, 100 and 150 min after oxidation. Tibia zinc concentration in nanoparticle zinc samples was significantly higher relative to the control and zinc-sulphate groups. Taken together, our data indicate that delivery of zinc in the structure of zinc-nano-methionine and zinc-nano-max at concentrations of 80 mg/kg of diet improves growth performance. However, dietary zinc-nano-sulphate decreased growth performance in broilers.

The effect of alpha-lipoic acid (ALA) supplementation on cardiovascular risk factors in men with chronic spinal cord injury: a clinical trial.

STUDY DESIGN: A randomized, double-blind, placebo-controlled clinical trial. OBJECTIVE: To assess the effect of alpha-lipoic acid (ALA) supplementation on IL-6, hs-CRP, FBS, anthropometric indices, food intake and blood pressure in male patients with chronic spinal cord injury (SCI). SETTING: Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran. METHODS: Fifty-eight men with chronic SCI participated in the study. Participants were divided in two groups: one group received 600 mg of supplemental ALA (n=28) and the other group received placebo (n=30) for 12 weeks. At the beginning and end of the study, biochemical parameters, anthropometric indices, blood pressure and dietary intakes were measured. Dietary intake was measured using N4 software, and statistical analyses were carried out using SPSS16. RESULTS: No significant reduction was found in IL-6 (P=0.97) and hs-CRP levels (P=0.23). There was significant reduction in fasting blood sugar (P=0.001), body weight (P=0.001), BMI (P=0.001), waist circumference (P=0.001) and blood pressure (P=0.001). Dietary intake was significantly reduced, including fat (P=0.001), carbohydrate (P=0.001), protein (P=0.002) and energy intakes (P=0.001). CONCLUSION: Lipoic acid supplementation had no significant effect on the measured inflammatory markers but it reduces fasting blood sugar, anthropometric parameters, food intake and blood pressure in men with chronic SCI.

Experimental analysis and numerical modeling of mollusk shells as a three dimensional integrated volume.

In this paper, a new numerical technique is presented to accurately model the geometrical and mechanical features of mollusk shells as a three dimensional (3D) integrated volume. For this purpose, the Newton method is used to solve the nonlinear equations of shell surfaces. The points of intersection on the shell surface are identified and the extra interior parts are removed. Meshing process is accomplished with respect to the coordinate of each point of intersection. The final 3D generated mesh models perfectly describe the spatial configuration of the mollusk shells. Moreover, the computational model perfectly matches with the actual interior geometry of the shells as well as their exterior architecture. The direct generation technique is employed to generate a 3D finite element (FE) model in ANSYS 11. X-ray images are taken to show the close similarity of the interior geometry of the models and the actual samples. A scanning electron microscope (SEM) is used to provide information on the microstructure of the shells. In addition, a set of compression tests were performed on gastropod shell specimens to obtain their ultimate compressive strength. A close agreement between experimental data and the relevant numerical results is demonstrated.