Organic solvent pretreatment to enhance enzymic saccharification of straw

Enzymic saccharification of wheat straw in the absence of any pretreatment was only about 20 %. Acid hydrolysis did not improve the overall cellulose enzymic breakdown, nor did pretreatment by flash autohydrolysis under pressure or sodium chlorite delignification. When wheat straw was treated with N-methyl-morpholine-N-oxide (MMNO) at J20°C for 20–30 min, this treatment and subsequent enzymic hydrolysis produced carbohydrate conversion of 73%. Similar results could be obtained by treating straw with 0·1 M sodium hydroxide. When MMNO treatment was combined with any other pretreatment, the saccharification yield was greatly enhanced. Nearly quantitative conversion was obtained by swelling straw in 0·1 M sodium hydroxide followed by MMNO treatment. The results show that lignin content of plant material does not represent the limiting factor to enzymic saccharification.     

The effect of sociodemographic diversity of residential customers on the financial risk experienced in the retail electricity market

The sociodemographic diversity of residential customers can affect the level of financial risk that an electricity provider experiences in the retail market. To demonstrate the relationship between sociodemographic diversity and financial risk, electricity consumption data drawn from the United Kingdom Power Networks ‘Low Carbon London’ project was analyzed to explore the relationship between sociodemographic diversity and financial risk experienced by electricity retailers. The results show that when increasing the sociodemographic diversity amongst a group of residential customers the effect on financial risk depends on the electricity consumption patterns of individual customers and the relationship of consumption patterns between residential customers. Increasing sociodemographic diversity amongst residential customers with very distinct energy consumption patterns can decrease the overall financial risk associated with the aggregated revenue received from these customers. However, the results showed that adding customers to a customer base without consideration for their sociodemographic background can cause the overall financial risk associated with the aggregated revenue received to change erratically. Whilst previous studies have considered customer diversity and its influence on peak electricity demand, this research advances the state-of-the-art by showing the importance of customer diversity to the financial quantity risk experienced by electricity retailers. This finding has serious implications for electricity providers seeking to mitigate financial risk in the retail electricity market.     

Stability and bioaccessibility of different forms of carotenoids and vitamin A during in vitro digestion

Vitamin A deficiency is a public health issue in developing countries and promoting dietary carotenoids as precursors is a promising strategy. However, carotenoids present in numerous fruits and vegetables are unstable and poorly bioaccessible. This study evaluated these two parameters during in vitro digestion of carotenoids and retinoids from carrot juice, raw and cooked spinach, micronutrient-fortified flour and standards without food matrix. Standards were unstable whereas vitamin A from fortified flour and native food carotenoids were generally better protected by the food matrix (30–100% remaining versus 7–30% for standards). Hydrothermal cooking did not influence spinach carotenoid digestive stability but decreased their contents, phenomenon compensated by a significantly better micellarisation from 15-fold for β-carotene to 72-fold for lutein. Finally, carrot juice provided the greatest amount of bioaccessible provitamin A with 1850 μg/100 g dry matter (DM) versus 790 and 80 μg/100 g DM in cooked and raw spinach, respectively.     

Bifidobacterium carbohydrases-their role in breakdown and synthesis of (potential) prebiotics

There is an increasing interest to positively influence the human intestinal microbiota through the diet by the use of prebiotics and/or probiotics. It is anticipated that this will balance the microbial composition in the gastrointestinal tract in favor of health promoting genera such as Bifidobacterium and Lactobacillus. Carbohydrates like non-digestible oligosaccharides are potential prebiotics. To understand how these bacteria can grow on these carbon sources, knowledge of the carbohydrate-modifying enzymes is needed. Little is known about the carbohydrate-modifying enzymes of bifidobacteria. The genome sequence of Bifidobacterium adolescentis and Bifidobacterium longum biotype longum has been completed and it was observed that for B. longum biotype longum more than 8% of the annotated genes were involved in carbohydrate metabolism. In addition more sequence data of individual carbohydrases from other Bifidobacterium spp. became available. Besides the degradation of (potential) prebiotics by bifidobacterial glycoside hydrolases, we will focus in this review on the possibilities to produce new classes of non-digestible oligosaccharides by showing the presence and (transglycosylation) activity of the most important carbohydrate modifying enzymes in bifidobacteria. Approaches to use and improve carbohydrate-modifying enzymes in prebiotic design will be discussed.     

Hybrid Approach for Addressing Uncertainty in Risk Assessments

Parameter uncertainty is a major aspect of the model-based estimation of the risk of human exposure to pollutants. The Monte Carlo method, which applies probability theory to address model parameter uncertainty, relies on a statistical representation of available information. In recent years, other uncertainty theories have been proposed as alternative approaches to address model parameter uncertainty in situations where available information is insufficient to identify statistically representative probability distributions, due in particular to data scarcity. The simplest such theory is possibility theory, which uses so-called fuzzy numbers to represent model parameter uncertainty. In practice, it may occur that certain model parameters can be reasonably represented by probability distributions, because there are sufficient data available to substantiate such distributions by statistical analysis, while others are better represented by fuzzy numbers (due to data scarcity). The question then arises as to how these two modes of representation of model parameter uncertainty can be combined for the purpose of estimating the risk of exposure. This paper proposes an approach (termed a hybrid approach) which combines Monte Carlo random sampling of probability distribution functions with fuzzy calculus. The approach is applied to a real case of estimation of human exposure, via vegetable consumption, to cadmium present in the surficial soils of an industrial site located in the north of France. The application illustrates the potential of the proposed approach, which allows the uncertainty affecting model parameters to be represented in a way that is consistent with the information at hand. Also, because the hybrid approach takes advantage of the “rich” information provided by probability distributions, while retaining the conservative character of fuzzy calculus, it is believed to hold value in terms of a “reasonable” application of the precautionary principle.     

Interaction between a coke and a tar. 2. Limit of tar penetration in coke porosity

The limit of penetration of a given coal-tar pitch into two cokes during mixing of the coke and liquid tar has been studied. It was shown that tar penetration is limited by compression of gas occluded in pores. Mercury porosimetry of cokes and pyrolysed coke-tar mixtures as well as micrographs of cokes impregnated with tar allow one to estimate the limiting pore diameter of tar penetration into coke at ca. 6 μm for the system considered.     

Sintering of latex particles in pigmented coatings. II. Influence of the latex particle size

The light-scattering coefficient S of coatings formulated from a mixture of an inorganic pigment and polystyrene latex particles may be enhanced significantly when the dry coating is heated in order to cause sintering of the polystyrene spheres. The relative increase in S depends on the size and the amount of the latex particles and the type of the inorganic pigment. Of the latexes examined (0.5, 0.2, 0.1, and 0.03 μm in diameter) the 0.2μm latex is the most effective in blends with platelike delaminated clay. The coatings based on spherelike precipitated calcium carbonate are less responsive to the heat treatment. The gloss of the clay–latex coatings is not significantly altered by the heat treatment up to 20 pph of latex; the gloss of the calcium carbonate coatings generally decreases upon heating.     

Electroless ultrasonic functionalization of diamond nanoparticles using aryl diazonium salts

We report a novel and very handful strategy for the functionalization of diamond nanoparticles (NDs), based on the ultrasound-assisted grafting of aryl groups from the electroless reduction of diazonium salts. For this study, 4-nitrobenzenediazonium salt was used as a model molecule and the reaction was investigated in neutral and acidic aqueous media. Spectroscopic evidence for the successful attachment of aryl groups to nanodiamonds (NDs) was given by IR and XPS which clearly detect characteristic NO₂ peaks. Moreover, the absence of any peaks from the ⁺N≡N group in the IR spectra is a clear indication of the chemical reduction of the parent diazonium salt at the surface of NDs. This spontaneous chemical modification of NDs by aryl diazonium salts was confined to the surface of the ND particles; indeed, XRD measurements have shown that the crystalline structure of the bulk of the particles was unaffected. It opens up new possibilities towards the control of the surface chemical composition of NDs using simple protocols operated in very soft conditions, i.e. in water at room temperature. It shows conclusively that the chemistry toolbox of experts interested in nanodiamonds should contain aryl diazonium salts, given their versatility in forming active platforms.     

The autochrome process

Abstract

The autochrome was the first successful commercial colour process. It was invented by Louis and Auguste Lumiere at the tum of the century, patented in 1903 and produced until the 1950s on a sheet film called ‘Filmcolor’. Many articles were published between 1903 when the autochrome process was unveiled to the public, and 1935 when the decline of the screen process began and the first colour films with chromogenic development appeared. There are detailed deseriptions of the plate's range of use, its characteristies and processing, but these publications are very sketchy as to the nature of the components. The most detailed documents, on which this article is based, are the ‘report on the titles and work of Louis Lumiere’ published in 1918, the factory notebooks written by Louis Lumiere or M. Perrigot,¹ and the archives of the Lumiere firm, which are now scattered in various locations.