Magnetic-separable robust microbeads using a branched polymer for stable enzyme immobilization

Uniform magnetic separable robust microbeads using a branched polymer were successfully developed for stable enzyme immobilization. The changed morphology of the microbeads was shown by scanning electron microscopy (SEM) analysis. The aldehyde groups on the polymers and imine groups derived from the Schiff base reaction between the aldehyde and amine moiety were found as the evidence of these reactions based on Fourier transform infrared (FT-IR) spectroscopy. The amine groups of the enzyme react with the aldehyde groups on the glutaraldehyde polymer so that the stable conjugations are formed. The specific activity of the conjugated enzyme was found to be retained more than 50%, but the reaction rate constant, K_m value was not changed, compared to the free enzyme. In addition, the enzyme conjugated in the microbeads was found to be highly stable for more than 50 days, pertaining over 60% of its initial activity, even after being reused more than 15 times repeatedly. Furthermore, the magnetic-driven controllability provided facile separable characters for the repeated recycling. It is expected that these microbeads can be utilized as a key tool for successful realization not only in enzymatic conversion processes but also in extended fields; bio-based sensors or analytical devices, bioprocessing, bioremediation, to name only a few of numerous areas.     

Multilateration with the wide-angle airborne laser ranging system: positioning precision and atmospheric effects

Numerical simulations based on previously validated models for the wide-angle airborne laser ranging system are used here for assessing the precision in coordinate estimates of ground-based cube-corner retroreflectors (CCR's). It is shown that the precision can be optimized to first order as a function of instrument performance, number of laser shots (LS's), and network size. Laser beam divergence, aircraft altitude, and CCR density are only second-order parameters, provided that the number of echoes per LS is greater than 20. Thus precision in the vertical is ~1 mm, with a signal-to-noise ratio of 50 at nadir, a 10-km altitude, a 20 degrees beam divergence, and ~5 x 10(3) measurements. Scintillation and fair-weather cumulus clouds usually have negligible influence on the estimates. Laser biases and path delay are compensated for by adjustment of aircraft offsets. The predominant atmospheric effect is with mesoscale nonuniform horizontal temperature gradients, which might lead to biases near 0.5 mm.     

Organocatalytic Asymmetric Mannich Reactions of 5H‐Oxazol‐4‐ones: Highly Enantio‐ and Diastereoselective Synthesis of Chiral α‐Alkylisoserine Derivatives

The first organocatalytic Mannich reaction of 5H‐oxazol‐4‐ones with various readily prepared aryl‐ and alkylsulfonimides has been developed. Two commercially available pseudoenantiomeric Cinchona alkaloids‐derived tertiary amine/ureas have been demonstrated as the most efficient catalysts to access the opposite enantiomers of the Mannich products with equally excellent enantio‐ and diastereoselectivities. From the Mannich adducts, important α‐methyl‐α‐hydroxy‐β‐amino acid derivatives, such as the α‐methylated C‐13 side chain of taxol and taxotere, can be conveniently prepared.     

Modern electric insulating materials for the insulation systems of rotating electric machines

Modern insulation systems of turbo- and hydrogenerators, large electric machines, and traction motors based on new electric insulating materials (EIMs) produced by the JSC Elinar Holding Company (Elinar HC) are described briefly. The technical characteristics of some new EIMs are given.     

The strengths of in vivo magnetic resonance imaging (MRI) to study environmental adaptational physiology in fish

Adaptational physiology studies how animals cope with their environment, even if this environment is subject to permanent fluctuations such as tidal or seasonal variations. Aquatic organisms are generally more prone to be exposed to osmotic, hypoxic and temperature challenges than terrestrial animals. Some of these challenges are more restraining in an aquatic environment. To date, very few studies have used in vivo magnetic resonance imaging (MRI) to uncover the physiological mechanisms that respond to or compensate for these challenges. This paper provides an overview of what has been accomplished thus far by using MRI to study the environmental physiology of fish. It introduces the reader to the use of small teleost fish such as carp (12 cm, 60 g) and eelpout (25 cm, 50 g) as models for such research and to provide new perceptions into the applicability of MRI tools based on new insights into the nature of MRI contrast. Representative MRI studies have made contributions to the identification of the lack of cell volume repair in stenohaline fish during osmotic stress. They have studied the underlying physiological mechanisms of brain anoxia tolerance in fish and have qualified the role of the cardio-circulatory system in setting thermal tolerance windows of fish.     

Online Signal Injection Through a Bus-Referenced Current Transformer

An online signal injection approach based on a special current transformer is proposed as part of a solution for improving the test setup of transfer function diagnostics of transformers. However, the method is general and applicable to many types of substation equipment, such as circuit breakers and transmission lines. The system allows a high-power, high-frequency test signal to be injected directly on a high-voltage bus of an energized system. Due to the self-contained nature of the injector, no external power supplies or signal generators are needed and the design does not need to be ground-referenced. The system can thus be at the bus potential. In conjunction with wireless communication for control, no isolator bushings are required and the device can be constructed as a sleeve to be mounted around the busbar. This allows for economical retrofitting to existing installations. In this paper, the operational need for such an injection device is discussed, followed by the theory behind the proposed concept. Finally, a low-voltage, optically controlled, self-powered prototype is designed and demonstrated online to show the practical validity of the concept.     

Phase‐Changeable Fatty Acid Available for Temperature‐Regulated Drug Release

This paper describes a mixture of fatty acids that is available for temperature‐controlled release of drugs. The mixture consists of two fatty acids with different melting points. At a specific composition, the mixture represents a single melting point of 38–40 °C which is slightly above the normal human body temperature. To demonstrate its use in the temperature‐regulated release, this study fabricates fatty acid‐incorporated polymer fibers containing dye‐loaded polymer particles in their core. Below the melting point of the mixture, it will be in a solid state to restrict the passing of dye loaded in the core whereas the dye can be released instantly through the generated pores at a temperature slightly higher than the melting point. The release profiles of the dye can be further manipulated by varying the amount of the mixture contained in the fibers and the composition of the mixture.