Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. IX. Alkylierungen mit 2,2,4-Trimethylpentan (Isooctan)

Acid-catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. IX. Alkylations with 2,2,4-Trimethylpentane (Isooctane) The non-conventional alkylation of benzene, toluene, ethyl- and isopropylbenzene, fluoro- and chlorobenzene with 2,2,4-trimethylpentane in the presence of acid catalysts is described. The composition of the rather complex reaction mixtures is determined by gas-liquid chromatography and mass spectrometry, tert. butylarenes being the main products beside alkylsubstituted indanes and tetralines. Their formation is interpreted as a competition between fragmentation and isomerization of the alkylating agent. By use of trifluoromethanesulfonic acid or combinations of catalysts from HF or HSO₃F with variant metallic fluorides at lower temperatures the selectivity of the reaction may be partially raised.     

PV solar electricity industry: Market growth and perspective

The photovoltaic (PV) solar electricity market has shown an impressive 33% growth per year since 1997 until today with market support programs as the main driving force. The rationales for this development and the future projections towards a 100 billion € industry in the 2020s, by then only driven by serving cost-competitively customer needs are described.The PV market, likely to have reached about 600 MW in the year 2003, is discussed according to its four major segments: consumer applications, remote industrial electrification, developing countries, and grid-connected systems. While in the past, consumer products and remote industrial applications used to be the main cause for turnover in PV, in recent years the driving forces are more pronounced in the grid-connected systems and by installations in developing countries. Examples illustrating the clear advantage of systems using PV over conventional systems based, e.g., on diesel generators in the rural and remote electrification sector are discussed. For the promotion of rural electrification combined with the creation of local business and employment, suitable measures are proposed in the context of the PV product value chain.The competitiveness of grid-connected systems is addressed, where electricity generating costs for PV are projected to start to compete with conventional utility peak power quite early between 2010 and 2020 if time-dependent electricity tariffs different for bulk and peak power are assumed. The most effective current-pulling force for grid-connected systems is found to be the German Renewable Energy (EEG) Feed-in Law where the customers are focusing on yield, performance, and long-life availability.The future growth in the above-defined four market segments are discussed and the importance of industry political actions in order to stimulate the markets either in grid-connected systems by feed-in tariff programs as well as for off-grid rural developing country applications by long-term financing schemes are pointed out.A technology roadmap is presented with special emphasis on the fact that different customer needs are best served with best-adopted technologies and not vice versa. The need for the third generation PV technologies, implying that so called first (c-Si-wafer)- and second (thin-film)- generation PV technologies will be overcome in a short to medium time scale, is obsolete; in contrast, the excellent scientific ideas developed within ‘Third generation’ concepts—like utilization of hot electrons, quantum wells and nanostructures—are shown to be part of ‘New Technologies’ opening new product ideas and additional market segments. The rationale for decreasing cost by increasing productivity for all technologies as well as the interpretation of price learning curves is presented.The role of PV in the future global energy supply chain is lined out. Due to a fast growing market driven by increasing widespread acceptance of PV, a substantial PV business and creation of employment in coming decades is expected. This in turn can provide solutions for nowadays global issues, such as a global energy justice by providing environmentally benign power to billions of people, who otherwise will lack energy solutions severely.     

Enhancing the sweetening power of lactose by enzymatic modification in the reformulation of dairy products

Lactose solutions of up to 50% (w/v) were incubated with lactases and glucose isomerases for subsequent implementation in dairy product samples to enhance sweetness. A degree of hydrolysis of >90% and of isomerisation of 50% were attainable. The sensory sweetening power of lactose in solutions of up to 50% (w/v) can be enhanced 2–3 times. Based on sensory experiments, application of this bi‐enzymatic system in yoghurt and pudding samples allowed for a 10–20% (w/w) reduction in the total sugar content, whilst retaining equal sweetness. The growth of yoghurt starter cultures was not affected, yet furosine formation more than doubled in high heated, enzyme‐modified milk.     

Sulfation of parabens and tyrosylpeptides by bacterial arylsulfate sulfotransferases

Arylsulfate sulfotransferase purified from Eubacterium A-44 has higher specific activity than the enzymes from Klebsiella K-36 and Haemophilus K-12. Propylparaben and butylparaben were good substrates among several parabens. The antibacterial activity of parabens was reduced by the sulfation of the phenolic hydroxy group. Tyrosine-containing peptides, kyotorphin, enkephalin and cholecystokinin non-sulfate, were effective as acceptor substrates by A-44, K-36 and K-12 sulfotransferases.     

Rotary Blanking ‐ a New Manufacturing Process

Rotary blanking is a method of blanking and punching with rotating tools whereby the cutting tools are fixed to a pair of rollers performing a continuous blanking operation on a strip of sheet metal. The purpose of this paper is to outline the determining conditions under which the rotary blanking process takes place and to discuss advantages, restrictions, applications and optimization of this technology.     

Pharmacokinetics of gadodiamide injection in patients with severe renal insufficiency and patients undergoing hemodialysis or continuous ambulatory peritoneal dialysis

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the pharmacokinetics, dialysability, and safety of gadodiamide injection in patients with severely reduced renal function not treated with renal replacement therapy and patients undergoing hemodialysis or continuous ambulatory peritoneal dialysis. MATERIALS AND METHODS: Twenty-seven patients--nine with severely reduced renal function (glomerular filtration rate, 2-10 mL/min), nine undergoing hemodialysis, and nine undergoing continuous ambulatory peritoneal dialysis--were followed up for 5, 8, and 22 days, respectively, after receiving gadodiamide injection (0.1 mmol per kilogram body weight). RESULTS: Gadodiamide injection caused no changes in renal function. In patients with severely reduced renal function, the elimination half-life of gadodiamide injection was prolonged (34.3 hours +/- 22.9) compared with data in healthy volunteers (1.3 hours +/- 0.25). An average of 65% of the gadodiamide injected was eliminated during a hemodialysis session. After 22 days of continuous ambulatory peritoneal dialysis, 69% of the total amount of gadodiamide was excreted; this reflects the low peritoneal clearance. In all patients, no metabolism or transmetallation of gadodiamide was found. There were no contrast material-related adverse events. CONCLUSION: Gadodiamide is dialysable and can safely be used in patients with severely impaired renal function or those undergoing hemodialysis or continuous ambulatory peritoneal dialysis. No precautions to increase the elimination are necessary.     

A fetal sheep liver extract reverses age-related increments in spontaneous and induced cytokine production by indirect environmental effects

BALB/c, DBA/2 and C57BL/6 mice of different ages (ranging from 8 to 110 weeks of age) were used as spleen cell donors to assay cytokine production from ConA activated spleen and Peyer's Patch (PP) lymphocytes. As reported in an earlier publication, there was an age-related decline in IL-2 production in all strains, with a general increase in IL-4 and IL-10 production with age, this being particularly marked for PP cell preparations. Similar conclusions were reached from independent analysis of CD44hi and CD44lo cell populations in these groups (memory vs. naive cells, respectively). Interestingly, IL-6 production was dramatically increased (some 4-5-fold in the different strains) and significantly increased levels of IL-6 were detected in the serum of aged mice. A previously described sheep fetal liver extract was able to reverse, to varying degrees, these cytokine changes associated with aging. Interestingly, when cells from aged mice were adoptively transferred to lethally irradiated young (8 week) recipients, the cytokine production phenotype of cells harvested from recipient mice 3 weeks later was that of the aged donor, unless recipients were treated continually with extract. Treatment of the donor alone produced minimal changes in cytokine production 3 weeks following adoptive transfer. The effect of extract was reversed in treated aged mice by concomitant daily intravenous infusion of the competitive inhibitor of nitric oxide synthesis (NG-monomethyl-L-arginine (NMMA)), which also decreased the increased serum nitrate levels in mice treated with extract. Our data suggest an important role for reactive nitrogen products, themselves induced by fetal liver extract, in age-associated changes in cytokine production.