Arthrobacter, Brachybacterium and Planococcus isolates identified from antarctic sea ice brine. Description of Planococcus mcmeekinii, sp. nov

Escherichia coli aspartate transcarbamylase (ATCase) catalyzes the first committed step in pyrimidine biosynthesis, the condensation of aspartate and carbamyl phosphate. ATCase is positively allosterically regulated by ATP and negatively regulated by CTP. We have used mild solvent perturbation to gain global molecular information about the mechanism of heterotropic allostery. The [NaCl], temperature, and osmotic pressure dependence of the enzymatic activity of ATCase has been examined in the presence and absence of allosteric effectors. The results indicate that: 1) Regulation of aspartate binding by CTP appears to involve a unique set of electrostatic interactions not involved in enzyme function in the presence of ATP or in the absence of effectors. 2) Aspartate binding is enthalpically driven in the presence and absence of allosteric effectors. 3) The apparent enthalpy and entropy of aspartate binding (delta H, delta S), and activation energy of catalysis (Ea) are substantially altered in the presence of CTP but not ATP. 4) The change in hydration of ATCase upon substrate binding is the same in the presence and absence of allosteric effectors. 5) The linkage between heterotropic and homotropic allostery is different for ATP and CTP.     

How managers interpret scanning information

When scanning, managers acquire and collect information about their environment to keep informed of its evolution, make decisions, and sometimes to anticipate changes. We attempted to understand this process and assess how French managers interpret scanning information to evaluate its importance. Our effort resulted in: (1) sixteen factors used by managers to make sense of the signs and signals they perceived when scanning; (2) a heuristic model of the process; and (3) two instances of the model. Our results suggested that ad hoc training should be provided and IT use should be fully investigated to enhance managers’ scanning skills if organizations wish to develop an ability to detect weak signs/signals, anticipate plausible change, and increase strategic decision effectiveness.     

A real-time control strategy for separation of highly polluted storm water based on UV-Vis online measurements--from theory to operation

'Classical' real-time control (RTC) strategies in sewer systems are based on water level and flow measurements with the goal of activation of retention volume. The control system rule of 'clean (storm water) runoff into the receiving water - polluted runoff into the treatment plant' has been thwarted by rough operating conditions and lack of measurements. Due to the specific boundary conditions in the city of Wuppertal's separate sewer system (clean stream water is mixed with polluted storm water runoff) a more sophisticated--pollution-based--approach was needed. In addition the requirements to be met by the treatment of storm water runoff have become more stringent in recent years. To separate the highly-polluted storm water runoff during rain events from the cleaner stream flow a pollution-based real-time control (P-RTC) system was developed and installed. This paper describes the measurement and P-RTC equipment, the definition of total suspended solids as the pollution-indicating parameter, the serviceability of the system, and also gives a cost assessment. A sensitivity analysis and pollution load calculations have been carried out in order to improve the P-RTC algorithm. An examination of actual measurements clearly shows the ecological and economic advantages of the P-RTC strategy.     

Towards co-design with users who have autism spectrum disorders

People with cognitive disorders, such as autism or Asperger’s syndrome, face many barriers when being involved in the co-design of information and communications technologies (ICT). Cognitive disorders may require that co-design techniques be modified to fit with individual abilities. Up until recently, with technology design, purpose and use being in the hands of ‘experts’ there was little opportunity for customisation. However, ICT bring together various threads that make open many new possibilities. Not only are technologies cheaper, more powerful and more available than ever, but now parents, support agencies and people with autism spectrum disorders expect information technologies to be part of their worlds, and they have the capacity to participate in co-design for customisation. However, co-design techniques have not evolved to the extent that they capture this potential democratisation of the ICT. This paper reports on an investigation of the potential to develop a set of guidelines for co-design techniques to enable people with autism spectrum disorders to participate in ICT design.     

Poly(β-malic acid alkyl esters) derived from 4-alkyloxycarbonyl-2-oxetanones obtained via the ketene route

Summary The cycloaddition of ketene to methyl, ethyl, isopropyl and n-butyl glyoxylates resulting from the scission of corresponding tartrate diesters has been used to prepare racemic 4-alkyloxycarbonyl 2-oxetanones. The reaction was conducted in dichloromethane at low temperature in the presence of triethylamine as catalyst. The use of a chiral tertiary amine instead of triethylamine yielded an optically active -lactone as shown in the case of methyl glyoxylate. The maximum enantiomeric excess was about 70 per cent and the sign of the elected enantiomer depended on the chiral base. Racemic n-butyl malolactonate was homopolymerized and copolymerized with benzyl malolactonate. High molecular weight polymers resulting from the homopolymerization of n-butyl malolactonate or from the copolymerization of this monomer with benzyl malolactonate were characterized by SEC and NMR. The ketene route was also used to synthesize racemic 4-trichloroethyloxycarbonyl 2-oxetanone, a -substituted -lactone, which had never been synthesized by other routes.     

Minimizing Bromate Concentration by Controlling the Ozone Reaction Time in a Full-Scale Plant

The latest European Directive 98/83/CE (5 December 1998), concerning the quality of water intended for human consumption, has set a two-stage parametric value for bromate. Bromate concentration will comply with 25 μg/L after December 25, 2003, and with 10 μg/L after December 25, 2008. Bromate formation in water is generally due to bromide oxidation during the ozonation stage. Due to higher temperatures, this latter parametric value is often exceeded in summer. Minimizing bromate levels is thus a crucial problem for drinking water producers. A bromate-minimizing strategy consists of shortening the reaction time between ozone and water. This can be done by neutralizing dissolved ozone residual with bisulfite at the exit of the ozone reactor chamber and/or by managing the introduction of ozone in different chambers depending on the water flow rate. This is only possible if, in our case, the disinfection goal for ozone is respected toward bacteria and viruses. The CT value must comply with 1.6 mg/min/L. In our plants, this value could be very large due to high contact time in and after leaving the ozone reactors.     

Characterization and photooxidative behaviour of nanocomposites formed with polystyrene and LDHs organo-modified by monomer surfactant

Layered double hydroxide (LDH) organo-modified by a surface-active monomer, 3-sulfopropyl methacrylate (SPMA) was used as filler for polystyrene (PS). Different nanocomposites SPMA/LDH:PS were prepared by bulk polymerization process using low amount of initiator. The two components, filler and polymer, as well as the degree dispersion of the reactive filler as a function of its loading in PS were characterized by a combination of several techniques: X-ray diffraction, high resolution ¹³C CP-MAS NMR, FTIR, UV-visible, thermal analysis, SEC and MET. The nanocomposites were submitted to UV-light exposures in the presence of oxygen. The oxidation photoproducts and the rates of oxidation were compared for the various samples. It was shown that the filler was not modifying the oxidation mechanism of the polymer, but had a slight effect on the oxidation rate.     

Transparent multiphasic polystyrene/epoxy blends

Blends of polystyrene (PS) with an epoxy monomer (DGEBA) and a tertiary amine (BDMA), were initially miscible at 120°C but phase‐separated at very low conversions in the course of polymerization. Although there was a significant difference between the refractive indices of polystyrene and the DGEBA/BDMA solution, the refractive index of the epoxy network increased in the course of polymerization, attaining a value close to that of PS at complete conversion. A sharp decrease of the light transmittance was observed at the cloud‐point, observed at very low conversions. However, the continuous increase of the refractive index of the epoxy phase with conversion produced an approximate matching of both refractive indices, leading to transparent materials at complete conversion. Morphologies generated by reaction‐induced phase separation depended on the molar mass distribution of polystyrene and its mass fraction in the blend. For a PS with a high value of the mass‐average molar mass (M_w), it was possible to generate a dispersion of PS particles in the epoxy matrix (blends containing 5 wt% PS), phase‐inverted morphologies (blends containing 15 wt% PS) and double‐phase morphologies (blends with 10 wt% PS). Therefore, PS/DGEBA/BDMA blends could be used to obtain transparent epoxy coatings toughened by polystyrene particles or transparent polystyrene parts reinforced by a dispersion of epoxy particles.