Why do batteries fail?

Battery failure and gradual performance degradation (aging) are the result of complex interrelated phenomena that depend on battery chemistry, design, environment, and the actual operation conditions. The current available knowledge on these matters results from a vast combination of experimental and modeling approaches. We explore the state of the art with respect to materials as well as usage (temperature, charge/discharge rate, etc.) for lead-acid, nickel-cadmium, nickel-metal hydride, and lithium-ion chemistries. Battery diagnosis strategies and plausible developments related to large-scale battery applications are also discussed.

Native fructose extracted from apple improves glucose tolerance in mice

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Fructose is one of the most abundant monosaccharide in nature. It is also the sweetest naturally occurring carbohydrate. Since decades, fructose used for food preparations is not provided by fruit or vegetable but by a chemical process of starch or inulin conversion. We processed a new method of fructose extraction from apple and investigated the acute and long term effect of this carbohydrate on glucose metabolism in C57Bl6/j mice. By using the glycemic index (GI), we have shown that one of the sugars obtained from apple, FructiLight, has a very low impact on glycemic and insulin response during acute treatment compared to other sugars. This carbohydrate, essentially constituted by fructose, has also beneficial properties when administrated for long term treatment. Indeed, as two other sugars extracted from apple (FructiSweetApple and FructiSweet67), FructiLight exposure during 21 weeks in beverage has promoted an enhancement of glucose tolerance compared to glucose treatment without affecting food intake and weight. All these results indicate that apple-extracted sugars and more precisely fructose from these fruits could be a promising way to produce new food and sweet beverages (AU)

Native fructose extracted from apple improves glucose tolerance in mice.

Fructose is one of the most abundant monosaccharide in nature. It is also the sweetest naturally occurring carbohydrate. Since decades, fructose used for food preparations is not provided by fruit or vegetable but by a chemical process of starch or inulin conversion. We processed a new method of fructose extraction from apple and investigated the acute and long term effect of this carbohydrate on glucose metabolism in C57Bl6/j mice. By using the glycemic index (GI), we have shown that one of the sugars obtained from apple, FructiLight, has a very low impact on glycemic and insulin response during acute treatment compared to other sugars. This carbohydrate, essentially constituted by fructose, has also beneficial properties when administrated for long term treatment. Indeed, as two other sugars extracted from apple (FructiSweetApple and FructiSweet67), FructiLight exposure during 21 weeks in beverage has promoted an enhancement of glucose tolerance compared to glucose treatment without affecting food intake and weight. All these results indicate that apple-extracted sugars and more precisely fructose from these fruits could be a promising way to produce new food and sweet beverages.

Kinetic studies and mathematical model for sucrose conversion by Aspergillus niger fructosyl-transferase under high hydrostatic pressure.

The effect of pressure on the kinetically controlled synthesis reaction catalyzed from sucrose by Aspergillus niger fructosyl-transferase was investigated at pH 5.5 and 40 degrees C. The overall reaction was split up into five main reactions that were studied under pressure in initial rate conditions with various substrate concentrations in the absence or in the presence of glucose 50 g/l. A global reaction model was worked out according to the mathematical expression of the initial rates as the products of a polynomial rational function of substrate concentration and a corrective term introducing pressure. Experimental data from sugar concentrations were correctly described by the model during the course of the reaction under pressure. Raising the pressure induced a decrease in fructo-oligosaccharides yield by inhibiting the main transfer reaction without affecting sucrose hydrolysis.

Digestion, excretion, and energy value of fructooligosaccharides in healthy humans.

The fate of fructooligosaccharides (FOS) in the human gastrointestinal tract was evaluated in six healthy volunteers over an 11-d period. After an equilibration phase, 20.1 g FOS/d was given in three identical postprandial doses. Distal ileal output of FOS and their constituent components were determined by intestinal aspiration after a single meal, and the amounts of FOS excreted in stools and urine were also measured. Most of ingested FOS, 89 +/- 8.3% (mean +/- SEM), was not absorbed in the small intestine, and none was excreted in stools, indicating that the portion reaching the colon was completely fermented by colonic flora. A small fraction of ingested FOS was recovered in urine. The mean estimated energy value of FOS was 9.5 kJ/g. We conclude that in healthy humans, FOS are only slightly digested in the small intestine and then fermented in the colon, resulting in reduced energy production.

Effects of fructo-oligosaccharides ingestion on fecal bifidobacteria and selected metabolic indexes of colon carcinogenesis in healthy humans.

Fructo-oligosaccharides (FOS) are a mixture of oligosaccharides consisting of glucose linked to fructose units. They are not digested in the human small intestine but fermented in the colon, where they could specifically promote the growth of some species of the indigenous microflora, especially bifidobacteria. We assessed in healthy humans the effects of FOS ingestion in fecal bifidobacteria and selected metabolic indexes potentially involved in colonic carcinogenesis. Twenty volunteers randomly divided into two groups were studied for three consecutive 12-day periods. During the ingestion period, they received 12.5 g/day FOS or placebo (saccharose) in three oral doses. Stools were regularly collected and analyzed. FOS ingestion led to an increase in fecal bifidobacterial counts [7.9 +/- 0.5 to 9.1 +/- 0.3 (SE) log colony-forming units/g wet wt, p < 0.01] and beta-fructosidase activity (9.6 +/- 1.9 to 13.8 +/- 1.9 IU/g dry wt, p < 0.01). In contrast, FOS ingestion had no significant effect on fecal total anaerobes, pH, the activities of nitroreductase, azoreductase, and beta-glucuronidase, and the concentrations of bile acids and neutral sterols. We conclude that ingestion of FOS, at a clinically tolerated dose of 12.5 g/day, led to an increase in colonic bifidobacteria. This effect was not associated in healthy humans with beneficial changes in various factors potentially involved in the pathogenesis of colonic cancer.