Poly(2-oxazoline)s with a 2,2′-Iminodiacetate End Group Inhibit and Stabilize Laccase

Poly(2-oxazoline)s (POxs) with 2,2′-iminodiacetate (IDA) end groups were investigated as inhibitors for laccase. The polymers with the IDA end groups are reversible, competitive inhibitors for this enzyme. The IC₅₀ values were found to be in a range of 1–3 mm . Compared with IDA alone, the activity was increased by a factor of more than 30; thus indicating that attaching a polymer chain to an inhibitor can already improve the activity of the former. The enzyme activity drops to practically zero upon increasing the concentration of the most active telechelic inhibitor, IDA-PEtOx₃₀-IDA (PEtOx: poly(2-ethyl-2-oxazoline)), from 5 to 8 mm . This unusual behavior was investigated by means of dynamic light scattering, which showed specific aggregation above 5 mm . Furthermore, the laccase could be stabilized in the presence of POx-IDA, upon addition at a concentration of 20 mm and higher. Whereas laccase becomes completely inactive at room temperature after one week, the stabilized laccase is fully active for at least a month in aqueous solution.     

A novel hybrid paper recommendation system using deep learning

Scientometrics - Every year, thousands of papers are published in journals and conferences by researchers in many different fields. These papers are an important guide for other researchers....     

Mannose based polymeric nanoparticles for lectin separation

The aim of this work is to synthesize the original, new polymeric nanoparticles for concanavalin A (Con A) purification. Nanoparticles were synthesized by surfactant free emulsion polymerization. In the polymerization prosedure, 1-O-(2′-hydroxy-3′-acryloyloxypropyl)-2,3:5,6-di-O-isopropylidene-α-D-mannofuranose (Man-OPA) was used as co-monomer and 2-hydroxyethylmethacrylate (HEMA) was used as a monomer. Man-OPA was characterized by Fourier Transform Infrared Spectroscopy (FTIR), nuclear magnetic resonance and elemental analysis techniques. Poly(HEMA-Man-OPA) nanoparticles were characterized by scanning electron microscopy, FTIR and Zeta Sizer. In adsorption?desorption experiments, maximum Con A adsorption capacity of poly(HEMA-Man-OPA) nanoparticles was found 630.6 mg/g nanoparticle (pH 7.5, 1.0 mg/mL). Adsorption?desorption experiments were repeated in four times. According to results, these nanoparticles could be used several times without significant decrease in Con A adsorption capacity.     

Seismic fragility assessment of effectiveness of viscous dampers in R/C buildings under scenario earthquakes

Fragility curves are used to represent the probabilities that the structural damages, under various level of seismic excitation, exceed specified damage states by means of earthquake intensity–damage relations. In this study, the fragility curves have been developed for comparative seismic evaluation of several retrofitting measures by incorporation of fluid viscous (VS) dampers applied to a representative high-rise reinforced concrete (R/C) office building located in Istanbul. In the retrofitting strategies considered, similar type of VS dampers was used and designed to provide the structure with three different effective damping ratios of 10%, 15%, and 20%. In the fragility analysis, a set of 240 artificially generated earthquake ground motions compatible with the design spectrum selected to represent the variability in ground motion was employed to study nonlinear dynamic responses of the structures before and after retrofit. Four damage states: slight, moderate, major, and collapse were defined to express the condition of damage. The fragility curves in this study are represented by lognormal distribution functions with two parameters and developed as a function of peak ground acceleration (PGA), spectral acceleration (S_a), spectral displacement (S_d). Comparison of the fragility curves indicated that the VS dampers were very effective in attenuating seismic structural response under various earthquake ground motions. It was also found that a two-fold reduction in the probability of exceeding damage states might be achieved by introducing passive VS damper systems.     

High velocity linear induction launchers

Electromagnetic launchers (EMLs) have received great attention in the last decades because of their potential application to a variety of energy, transportation, space, and defense systems. Particularly, they can serve as kinetic weapons, such as ground-based and naval artillery, space-based anti-missile guns, Earth-to-Orbit launcher, and mass transportation. The main advantage is that EMLs can accelerate projectiles to hyper velocities, i.e. velocities greater than those achievable with conventional cannons. The Linear Induction Launcher (LIL) is an air-cored electromagnetic coil launcher operating on the principle of the induction motor. Polyphase excitation of the coils constituting the barrel is designed to create an electromagnetic wave packet, which travels with increasing velocity from the breech to the muzzle. The projectile is a hollow conducting cylinder (sleeve) carrying the payload within it. Relative motion (slip) of the wave packet with respect to the projectile induces azimuthal currents in the sleeve that interacts with the exciting magnetic field to produce both propulsive and centering forces. This paper deals with the design of a high velocity linear induction launcher with muzzle velocity up to 6000 m/s. It addresses the design specifications of the launcher and utilizing a projectile weighing 1 kg. In the paper, the design specifications with simulation results for the phase voltages, the currents, the velocity, and the temperature rise of the sleeve are presented.     

Characterization of the effective atomic number for first row transition elements by the ratio of coherent to compton scattering intensities obtained by wavelength dispersive X-ray fluorescence

The effective atomic numbers of compounds of the first row transition elements were determined experimentally by a scattering method using wavelength dispersive X-ray fluorescence spectrometer. A calibration curve was created by using the intensity ratios of coherent to Compton scattered peaks of pure elements from atomic number 13–48. This relationship was employed to determine the effective atomic numbers of the compounds. The effective atomic numbers were also calculated by using empirical formulas from the literature. Mass attenuation coefficients were calculated using software. The experimentally measured values of the effective atomic numbers with the calculated values by empirical formulas were comparable.     

SAR distribution in human beings when using body-worn RF transmitters

This study analyzes the exposure of the human torso to electromagnetic fields caused by wireless body-mounted or handheld devices. Because of the frequency and distance ranges from 30-5800 MHz and 10 to 200 mm, respectively, both near-field and far-field effects are considered. A generic body model and simulations of anatomical models are used to evaluate the worst case tissue composition with respect to the absorption of electromagnetic energy. Both standing wave effects and enhanced coupling of reactive near-field components can lead to a specific absorption rate (SAR) increase in comparison to homogeneous tissue. In addition, the exposure and temperature increase of different inner organs is assessed. With respect to compliance testing, the observed SAR enhancement may require the introduction of a multiplication factor for the spatial peak SAR measured in the liquid-filled phantom in order to obtain a conservative exposure assessment. The observed tissue heating at the body surface under adiabatic conditions can be significant, whereas the temperature increase in the inner organs turned out to be negligible for the cases investigated.     

Enhanced Morphological Stability in Sb-Doped Ge

The axial heat processing (AHP) crystal growth technique was used to investigate the morphological stability of faceted solid/liquid (s/l) interfaces. Six Sb-doped Ge single crystals containing 2.3 × 10⁻² to 2.3 × 10⁻¹ at. pct Sb were grown at pulling rates of 10 to 20 mm/h. These include two bicrystals specifically designed to investigate the effect of slight misorientation on stability. Faceted growth with a kinetic supercooling on the order of 0.15 K was achieved, and a characteristic two-dimensional W instability boundary, an inverted crater in three dimensions, was observed. The crystals exhibited enhanced morphological stability over the predictions of the constitutional supercooling (CS) criterion and the Mullins and Sekerka (MS) stability criterion, with the highest stability in the center of the W. These results are examined with current analytical stability theories accounting for convection and kinetics. An alternate model is proposed based on anisotropic kinetics and the competition between lateral spreading on a faceted interface and the amplification rate of an interfacial perturbation.

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