Oxidative coupling of various aromatic phenols and anilines in water using a laccase from Trametes villosa and insights into the ‘PEG effect’

BACKGROUND: Studies with peroxidases (EC 1.11.1.7) have demonstrated extended lifetimes for conversion of phenolics into insoluble polymers in the presence of polyethylene glycol (PEG). Yet the mechanism of this ‘PEG effect’ has eluded investigators. The effectiveness of a laccase (EC 1.10.3.2) with PEGs of various average molar masses on the conversion of phenol, o‐, m‐, p‐cresols, aniline, o‐, m‐, and p‐toluidines was investigated. This structure‐activity comparison, with and without the additive, could provide further insight into the ‘PEG effect’. RESULTS: The ‘PEG effect’ was observed only with the cresols and only with PEGs of average molar mass ≥ 1450. Other additives capable of H‐bonding, such as polyvinylpyrrolidone, had similar results. When a ‘PEG effect’ was observed there was a linear relationship between the amount of additive used and the amount incorporated into the precipitate, suggesting a strong interaction between products and PEG, which was confirmed by nuclear magnetic resonance spectroscopy. Optimum pH was not affected by the quantity or molar mass of the PEG added. CONCLUSION: PEG only enhances the laccase‐catalyzed oxidative coupling of certain substrates implying a product‐additive relationship that may be related to the functionality and substituent positioning of the substrate. Copyright © 2011 Society of Chemical Industry     

Characteristics of a high brightness gaseous field ion source employing tungsten-carbon doped NiAl needles

We report on the characterization of a high brightness gaseous field ion source using an emitter made of a NiAl needle containing tiny spherical tungsten-carbon precipitates. By field evaporation of such a multiphase alloy, a surface protrusion is formed out of a precipitate, which can act as a small source size field ion emitter. The emission current-voltage characteristics of this emitter were recorded for a variety of parameters. The results obtained suggest that its application as a stable ion source is possible even on long term operation.     

Peak-Average-Power Ratio Techniques for 5G Waveforms Using D-SLM and D-PTS

Multicarrier Waveform (MCW) has several advantages and plays a very important role in cellular systems. Fifth generation (5G) MCW such as Non-Orthogonal Multiple Access (NOMA) and Filter Bank Multicarrier (FBMC) are thought to be important in 5G implementation. High Peak to Average Power Ratio (PAPR) is seen as a serious concern in MCW since it reduces the efficiency of amplifier use in the user devices. The paper presents a novel Divergence Selective Mapping (DSLM) and Divergence Partial Transmission Sequence (D-PTS) for 5G waveforms. It is seen that the proposed D-SLM and PTS lower PAPR with low computational complexity. The work highlighted a combination of multi-data block partial transmit schemes along with tone reservation. In this, an overlapping factor is used to determine the number of data blocks for every group. Here, considering only those data blocks that have minimum signal power, the use of DSLM and DPTS are required to eliminate the segment’s peaks. Simulation results reveal that the suggested hybrid technique proves to be better than the conventional PTS scheme. Furthermore, the power saving performance of FBMC and NOMA is compared with the Orthogonal Frequency Division Multiplexing (OFDM) waveform.     

Potentials of wind energy development for water desalination in Jordan

The potential of the development of water desalination using wind energy in Jordan was studied. Eleven wind solar sites were considered. The results show that these sites can be divided, in terms of the yearly total amount of desalinated water, into three categories. One is considered favourable, which includes Ras Muneef, Mafraq, and Aqaba. Their water production adds up to about 75% of all water produced from all 11 sites combined. Others are considered to be promising (about 24% in total), which include H-5, Irbid, and Ma'an. The rest of sites considered are found to be very poor, which include H-4, Amman, Queen Alia Airport, Shoubak, and Deiralla, with traces of water produced (less than 1%). © 1998 John Wiley & Sons, Ltd.     

Rheological and Mechanical Properties of Clay-Thermoplastic Elastomers Derived from PVC and NBR

Based on the character of a clay that could be separated into many 1-nm thickness monolayers, clay poly(vinylchloride)-nitrile butadiene rubber (PVC/NBR) thermoplastic elastomers (TPEs) were acquired using a Brabender Plasticorder at 150°C and 50 rpm rotor speed. Clay concentrations were progressively increased up to 10 phr of PVC/NBR composites. The rheological behavior of the clay PVC/NBR blends was assessed by dynamic mechanical analysis, as well as Brabender torque rheometry. The results revealed that the complex modulus (E?) and elastic modulus (E′) increased with clay loading, indicating that the actual strength of the blends improved. Tensile properties of the PVC/NBR-clay formulations with different filling amounts were studied. The results showed that the mechanical performance of the rubbery samples improved with clay loadings. The observed trend has been attributed to the reinforcing role played by layered clay due to better dispersion as well as improved interactions.     

Synthesis and antiplatelet effects of an isoxazole series of glycoprotein IIb/IIIa antagonists

Despite the excellent in vitro potency of a series of benzamide glycoprotein IIb/IIIa antagonists, which have been reported previously, poor in vivo potency in the inhibition of platelet aggregation was observed when the most potent inhibitor XU057 was dosed intravenously to dogs. In this communication, we report that replacement of the benzamide in XU057 with an isoxazolecarboxamide resulted in significant improvement in in vivo potency. More importantly, the analogue XU065 showed an excellent oral antiplatelet effect in dogs.     

Development of systemic lupus erythematosus in a male patient after 14 years on hemodialysis

Graves' disease (GD), myasthenia gravis (MG), and polymyositis (PM) are organ-specific autoimmune diseases. The association between GD and MG is well known, and an association between MG and PM has been reported. However, only one patient with all three diseases has been reported. We describe a patient with GD and PM developing 6 and 29 years, respectively after the onset of MG. This case suggests that the expression of autoimmunity occurred over a prolonged period of time and these organ-specific autoimmune diseases may be induced by a similar mechanism.     

Solidification of phase change material on vertical cylindrical surface in holdup air bubbles

Solidification of phase change material around a vertical cylindrical surface was studied to investigate the performance of ice storage system and stored thermal energy. Air bubbles were generated in the phase change material at various air flow rate as a gas holdup to enhance the heat transfer rate and accelerate the ice layer growth at the solid–liquid interface. The test tube surface was cooled by ethylene glycol–water solution at a flow rate of 40% concentration by weight. The ice layer growth and solidification front velocity at solid–liquid interface were estimated from the temperature–time recorded data of a set of thermocouples fixed in a radial position perpendicular to cooled surface. The ice layer growth at the first instants of solidification process is much higher. Thereafter it decreased gradually according to the increasing of thermal resistance of ice layer. The increasing of ethylene glycol–water solution mass flow rate seems to accelerate the solidification process with small rate. The effect of air bubbles agitation was found to increase the ice layer growth rate and solidification front velocity by about of 20–45%. As a consequence the stored thermal energy was increased by about 55–115% with increasing air bubbles flow according to the attribute of generates turbulence at the solid–liquid interface. The measured data showed that with stirring the bulk water in energy storage tank, the storage time can be reduced by 10–35% of that without stirring.     

Thermotropic liquid crystalline polymers

Summary A new nematic monomer — p-( -acryloyloxycaproyloxy)p-methoxyphenylbenzoate — was synthesized. A homepolymer of this monomer and its copolymer with cholesteryl--acryloyloxycapronate were prepared by radical polymerization. The homopolymer forms the mesophase of nematic type. The copolymer forms the cholesteric mesophase that shows selective light reflection. The maximum wavelength of the reflected light is equal to 495–500 nm and is not changed on temperature.Part 7. R. V. Talroze, V. V. Sinitzyn, V. P. Shibaev, N. A. Plate Polymer Bull. 6, 309 (1982)