Green energy in Europe : The surprising green electricity market in UK

Just over six months ago, views of experts on the green electricity market in the United Kingdom were when not pessimistic, rather cautious. Then, with the summer of 2001 blew a wind of change. Juice, GreenPlan, Green Tariff and many more new green energy products flooded the market supported by massive marketing campaigns using all possible media in the United Kingdom. Laetitia Ouillet, www.greenprices.com focuses on the latest developments of the green electricity markets in the United Kingdom over the past six months.     

Dividing to unveil protein microheterogeneities: traveling wave ion mobility study

Overexpression of a protein in a foreign host is often the only route toward an exhaustive characterization, especially when purification from the natural source(s) is hardly achievable. The key issue in these studies relies on quality control of the purified recombinant protein to precisely determining its identity as well as any undesirable microheterogeneities. While standard proteomics approaches preclude unbiased search for modifications, the optional technique of top-down tandem mass spectrometry (MSMS) requires the use of highly accurate and highly resolved experiments to reveal subtle sequence modifications. In the present study, the top-down MSMS approach combined with traveling wave ion mobility (TWIM) separation was evaluated for its ability to achieve high sequence coverage and to reveal subtle microheterogeneities that were hitherto only accessible with Fourier-transform ion cyclotron resonance-MS instruments. The power of this approach is herein illustrated in an in-depth analysis of both the wild type and K496C variant of the recombinant X domain (XD; aa's 459-507) of the measles virus phosphoprotein expressed in Escherichia coli . Using top-down MSMS combined with TWIM, we show that XD samples occasionally exhibit a microheterogeneity that could not be anticipated from the nucleotide sequence of the encoding constructs and that likely reflects a genetic drift, neutral or not, occurring during expression. In addition, a 1-oxyl-2,2,5,5-tetramethyl-δ3-pyrroline-3-methyl methanethiosulfonate nitroxide probe that was grafted onto the K496C XD variant was shown to undergo oxidation and/or protonation in the electrospray ionization source, leading to artifactual mass increases.     

Effect of organic P forms and P present in inorganic colloids on the determination of dissolved P in environmental samples by the diffusive gradient in thin films technique, ion chromatography, and colorimetry

The speciation of P in environmental samples is operationally defined, since it depends on the analytical method used. In this study, we compared four methods to measure P in solution: ion chromatography (IC), the malachite green colorimetric method (CM), the diffusive gradient in thin films technique (DGT) and, for total dissolved P, optical inductively coupled plasma (ICP). These methods were compared on three sets of solutions (filtered over <0.45 μm): solutions with model organic P compounds, suspensions of synthesized inorganic Fe and Al colloids loaded with P, and environmental samples. The environmentally relevant organic P compounds were only marginally detected by CM and IC. Substantial fractions of certain organic P compounds contributed to the DGT measurement. Colorimetric analysis of DGT eluates detected in general less P than ICP analysis, indicating that these organic P compounds sorbed on the zero sink layer. Phosphorus associated with inorganic colloids was completely recovered by CM, but not by IC and least by DGT. Measurements on a wide set of 271 environmental samples (soil pore waters, groundwaters, and surface waters) suggest that surface water P is largely present as orthophosphate and phosphate sorbed onto inorganic colloids, whereas organic P contributes more in groundwaters.     

Fractionation of whey protein isolate with supercritical carbon dioxide-process modeling and cost estimation

An economical and environmentally friendly whey protein fractionation process was developed using supercritical carbon dioxide (sCO₂) as an acid to produce enriched fractions of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) from a commercial whey protein isolate (WPI) containing 20% α-LA and 55% β-LG, through selective precipitation of α-LA. Pilot-scale experiments were performed around the optimal parameter range (T = 60 to 65 °C, P = 8 to 31 MPa, C = 5 to 15% (w/w) WPI) to quantify the recovery rates of the individual proteins and the compositions of both fractions as a function of processing conditions. Mass balances were calculated in a process flow-sheet to design a large-scale, semi-continuous process model using SuperproDesigner® software. Total startup and production costs were estimated as a function of processing parameters, product yield and purity. Temperature, T, pressure, P, and concentration, C, showed conflicting effects on equipment costs and the individual precipitation rates of the two proteins, affecting the quantity, quality, and production cost of the fractions considerably. The highest α-LA purity, 61%, with 80% α-LA recovery in the solid fraction, was obtained at T = 60 °C, C = 5% WPI, P = 8.3 MPa, with a production cost of $8.65 per kilogram of WPI treated. The most profitable conditions resulted in 57%-pure α-LA, with 71% α-LA recovery in the solid fraction and 89% β-LG recovery in the soluble fraction, and production cost of $5.43 per kilogram of WPI treated at T = 62 °C, C = 10% WPI and P = 5.5 MPa. The two fractions are ready-to-use, new food ingredients with a pH of 6.7 and contain no residual acid or chemical contaminants.     

Organochlorine pesticide residues in domestic fowl (Gallus domesticus) eggs from central Kenya

In 367 domestic fowl (Gallus domesticus) eggs collected from 61 farms, residues of 10 pesticides were detected in various combinations and in the following order of frequency: p,p′-DDE (in 100% of the eggs), p,p′-DDT (98%), dieldrin (95%), Indiane (66%), p,p′-DDD (46%), o,p′-DDT (17%), β-HCH (9%), γ-HCH (5%), endrin (4%) and aldrin (0–5%). No residues of heptachlor, heptachlor epoxide, HCB or PCBs were found. The mean concentration (0–70 mg kg^?1 eggs; range <0–01–10–25) of total DDT exceeded the extraneous residue limit (ERL) of 0–50 mg kg^?1. The mean dieldrin residue level (0–35 mg kg^?1; range 0–01–14–90) was 3–5 times higher than the ERL (0–10 mg kg^?1). Only 3% of the eggs exceeded the ERL for Indane. The 156 eggs from free-range hens had significantly (P<0–05) higher residue concentrations of total DDT, dieldrin and Iindane than eggs collected from hens kept in enclosures. The mean ratio [p,p′-DDT]/[p,p′-DDE] in eggs from enclosed hens (0–97) was significantly higher (P<0–01) than in eggs from free-range hens (0–53), indicating that the former had a more direct exposure to p,p′-DDT, whereas the latter obtained more of it after environmental conversion to p,p′-DDE. Eggs from a rice-growing area had the highest concentrations of all pesticide residues detected. Accumulation ratios indicated that the levels of DDT and Iindane in the feed of enclosed hens could account for the levels in the corresponding eggs. The much higher accumulation ratios calculated for the free-range hens demonstrated that the feed ingested by these chickens obviously contained ingredients additional to those sampled, and revealed probable extensive environmental contamination by these persistent pesticides. The present results indicate that there is a need to identify sources of dieldrin in the eggs of domestic fowls and, where necessary to investigate local wildlife samples. The amounts of total DDT and dieldrin in eggs in this study seem to be higher than reported from any other country. Toxicological evaluation of the results indicates that, at lest in parts of KEnya there is a need for improved practices in the use of some organochlorine pesticides.     

Pesticides in the Rhône river delta (France): basic data for a field-based exposure assessment

The pesticide concentration levels flowing into paddy fields and surrounding lagoons of the Rh?ne river delta were investigated over a period of 6 months in 2004. Water samples were collected at the outlets of the major ditches and in the lagoons in order to study the seasonal variation in pesticide concentrations and the spatial contamination profile. Twenty four pesticides were monitored, mainly herbicides and insecticides. Rice pesticides accounted for 90% of the detection rates while the pesticides transported by the Rh?ne river water dissolved phase only accounted for 10%. Pretilachlor, oxadiazon, MCPA and bentazone herbicides were found at the highest frequencies into the effluent waters of ditches with maximum concentration levels of 1.2, 0.8, 2.5 and 1.6 microg/L, respectively. Only one insecticide, tebufenozide, was sporadically detected at a maximum concentration level of 0.12 microg/L. There were two main peaks of contamination. The first one in April corresponded to the use of pre-emergence herbicides (oxadiazon and pretilachlor) and the second one in June was related to the post-emergence herbicides (MCPA and bentazone). These concentration peaks were well correlated with the pesticide application period time and rapid pesticide transfer (1-2 weeks) from fields to lagoons were observed. Increased loads of the pre-emergence herbicides were induced by the specific management of paddy fields which includes water emptying of fields before and after rice seeding. Pesticide dissipation into the lagoons occurred very quickly and the duration of the exposure of non-target aquatic organisms to high pesticide concentrations (in total a few microg/L level) was no longer than 2 weeks. According to the physico-chemical properties of the chemicals, contrasting results were observed when studying the spatial variation in pesticide concentrations through the lagoons. The concentrations of bentazone and MCPA, two substances with high phototransformation abilities, quickly decreased between the ditches and the lagoons while the oxadiazon and pretilachlor concentrations were more homogeneous.