n−3 and n−6 fatty acid enrichment by dietary fish oil and phospholipid sources in brain cortical areas and nonneural tissues of formula-fed piglets

Sufficient availability of both n-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFA) is required for optimal structural and functional development in infancy. The question has been raised as to whether infant formulae would benefit from enrichment with 20 and 22 carbon fatty acids. To address this issue, we determined the effect of fish oil and phospholipid (LCPUFA) sources on the fatty acid composition of brain cortical areas and nonneural tissues of newborn piglets fed artificially for 2 wk. They were fed sow milk, a control formula, or the formula enriched with n-3 fatty acids from a low-20:5n-3 fish oil added at a high or a low concentration, or the formula enriched with n-3 and n-6 fatty acids from either egg yolk- or pig brain-phospholipids. Both the fish oil- and the phospholipid-enriched formula produced significantly higher plasma phospholipid 22:6n-3 concentrations than did the control formula. The 22:6n-3 levels in the brain, hepatic, and intestinal phospholipids were significantly correlated with plasma values, whereas cardiac 22:6n-3 content appeared to follow a saturable dose-response. Feeding sow milk resulted in a much higher 20:4n-6 content in nonneural tissues than did feeding formula. Supplementation with egg phospholipid increased the 20:4n-6 content in the heart, red blood cells, plasma, and intestine in comparison to the control formula, while pig brain phospholipids exerted this effect in the heart only. The addition of 4.5% fish oil in the formula was associated with a decline in 20:4n-6 in the cortex, cerebellum, heart, liver, and plasma phospholipids, whereas using this source at 1.5% limited the decline to the cerebellum, liver, and plasma. Whatever the dietary treatment, the phosphatidylethanolamine 20:4n-6 level was 10–20% higher in the brain temporal lobe than in the parietal, frontal, and occipital lobes in the temporal lobe by administering the formula enriched with egg or brain phospholipids. In conclusion, feeding egg phospholipids to neonatal pigs increased both the 22:6n-3 content in the brain and the 20:4n-6 content in the temporal lobe cortex. This source also increased the 22:6n-3 levels in nonneural tissues with only minor alterations of 20:4n-6. These data support the notion that infant formulae should be supplemented with both 22:6n-3 and 20:4n-6 rather than with 22:6n-3 alone.     

From Al2O3-supported Ni(II)-ethylenediamine Complexes to CO Hydrogenation Catalysts: Importance of the Hydrogen Post-treatment Evidenced by XPS

Ni (7 wt%)/Al₂O₃ catalysts prepared by decomposition of Ni(II)-ethylenediamine complexes in inert atmosphere initially contain a mixture of metallic and oxidized nickel. X-ray photoelectron spectroscopy shows that after a hydrogen treatment at 500 °C, the system contains more metallic nickel than catalysts prepared from the usual precursor, nickel nitrate. Carbonaceous species resulting from the partial oxidation of ethylenediamine are also eliminated. The catalyst post-treated in hydrogen exhibits a high metallic surface area accessible to reactants and is able to catalyze CO methanation.     

Is direct microwave heating well suited for sintering ceramics?

This paper presents a thorough analysis of direct microwave heating as a sintering process of ceramic materials. It questions why susceptor-assisted microwave heating is used in most experimental works, although direct microwave coupling is preferable for taking advantage of the possible beneficial effects of the microwave field on the sintering phenomena. This issue was investigated by conducting both experiments and numerical simulations. The experiments consisted of sintering alumina and yttria doped zirconia powder samples in a 2.45 GHz resonant cavity with automatic thermal monitoring, whereas the numerical simulations coupled electromagnetics, thermal transfer and sample deformation. Alumina and yttria doped zirconia are widely used materials and they exhibit different microwave field behaviours (transparent and absorbent, respectively), which are representative of most ceramic materials. The influence of the insulating material was discussed by considering different sintering cell designs. The very low coupling capacity of alumina made its direct heating very difficult. It was therefore necessary to apply a strong electric field to heat it. This situation promoted the absorption of microwave energy by other elements such as the insulating material, leading to heating instabilities and degradation of the insulation cell. In the case of zirconia, its coupling properties change abruptly with increasing temperature. It is poorly absorbent at low temperature, highly absorbent at intermediate temperature and it finally becomes reflective at the end of the sintering process. The consequences of this behaviour are (i) a very difficult control of direct heating (ii) a propensity to form damaging hot spots and (iii) the impossibility to reach high temperatures without forming plasma. Therefore, this experimental and numerical study showed that direct microwave heating is not suitable for conducting reliable and homogeneous sintering of classical ceramics. This explains why susceptor-assisted heating is most of time preferred.