Stress–strain properties and thermal resistance of polyurethane–polyepoxide interpenetrating polymer networks

Two-component interpenetrating polymer networks (IPN) of the SIN type (simultaneous interpenetrating networks) were prepared from three different polyurethanes and two epoxies. The linear prepolymers were combined in solution, together with crosslinking agents and catalysts, films cast, and subsequently chain extended and crosslinked in situ. Two of the IPN's showed significant improvement in thermal resistance, as measured by thermogravimetric analysis (TGA). All of the IPN's showed maxima in tensile strength significantly higher than the tensile strengths of the component networks at 25% polyurethane and minima at 75% polyurethane. The minima were explained by an initial dilution of the strong polyurethane hydrogen bonds by the epoxies, and the maxima, by an increase in crosslink density due to interpenetration.     

Evaluating metabolites in patients with major depressive disorder who received mindfulness-based cognitive therapy and healthy controls using short echo MRSI at 7 Tesla

Objectives

Our aim was to evaluate differences in metabolite levels between unmedicated patients with major depressive disorder (MDD) and healthy controls, to assess changes in metabolites in patients after they completed an 8-week course of mindfulness-based cognitive therapy (MBCT), and to exam the correlation between metabolites and depression severity.

Materials and methods

Sixteen patients with MDD and ten age- and gender-matched healthy controls were studied using 3D short echo-time (20 ms) magnetic resonance spectroscopic imaging (MRSI) at 7 Tesla. Relative metabolite ratios were estimated in five regions of interest corresponding to insula, anterior cingulate cortex (ACC), caudate, putamen, and thalamus.

Results

In all cases, MBCT reduced severity of depression. The ratio of total choline-containing compounds/total creatine (tCr) in the right caudate was significantly increased compared to that in healthy controls, while ratios of N-acetyl aspartate (NAA)/tCr in the left ACC, myo-inositol/tCr in the right insula, and glutathione/tCr in the left putamen were significantly decreased. At baseline, the severity of depression was negatively correlated with my-inositol/tCr in the left insula and putamen. The improvement in depression severity was significantly associated with changes in NAA/tCr in the left ACC.

Conclusions

This study has successfully evaluated regional differences in metabolites for patients with MDD who received MBCT treatment and in controls using 7 Tesla MRSI.

     

Mass Transfer and Immobilized Organic Phase Instability Studies for Cobalt(II)–Nickel(II) Separation by PEHFSD

Pseudo-emulsion-based hollow-fiber strip dispersion (PEHFSD) technique was examined as an alternative to solvent extraction for simultaneous separation and concentration of cobalt(II)–nickel(II) mixture using Cyanex-272 as the extractant. Experiments were carried out by continuous recirculation of the feed and pseudo-emulsion phases through a hollow-fiber module. The separation factor increased rapidly after 60 min of operation. The maximum value after 120 min of operation was ～128 (pH = 6.5) for the operating conditions studied. The mass transfer resistance from the extraction reaction appeared to be dominant. The results of mathematical modeling of the mass transfer process indicated that higher separation factor and extraction rate can be achieved using PEHFSD in comparison to solvent extraction. Mixing of the stripping and the feed solution was observed at high dispersed phase volume fraction in the pseudo-emulsion and low flow rate of this phase. The maximum value of backtransport flux from the stripping phase due to mixing was estimated to be approximately two orders lower than the initial extraction rates.     

Optimization of Synthesis Conditions of Monoclinic Potassium Niobate (KNbO3) and its Effect on Morphology

Stoichiometric orthorhombic and monoclinic KNbO₃ samples have been prepared through low temperature–time hydrothermal method. Optimized synthesis conditions for monoclinic KNbO₃ have been found to be hydrothermal treatment of 15M precursor solution at 160°C for 8 h. Transformation of orthorhombic KNbO₃ to monoclinic KNbO₃ has been established through thermodynamic considerations. Further, successful synthesis of orthorhombic KNbO₃ has also been achieved under moderated conditions. FESEM analyses of synthesized materials revealed that initially formed block‐like structures either stack upon one another to form hierarchical morphology or join end to end to form rods. Observations have been substantiated through HRTEM, EDX, FTIR, and Raman spectra analyses.     

Modulation of Ultrafast Conformational Dynamics in Allosteric Interaction of Gal Repressor Protein with Different Operator DNA Sequences

Although all forms of dynamical behaviour of a protein under allosteric interaction with effectors are predicted, little evidence of ultrafast dynamics in the interaction has been reported. Here, we demonstrate the efficacy of a combined approach involving picosecond‐resolved FRET and polarisation‐gated fluorescence for the exploration of ultrafast dynamics in the allosteric interaction of the Gal repressor (GalR) protein dimer with DNA operator sequences O_E and O_I. FRET from the single tryptophan residue to a covalently attached probe IAEDANS at a cysteine residue in the C‐terminal domain of GalR shows structural perturbation and conformational dynamics during allosteric interaction. Polarisation‐gated fluorescence spectroscopy of IAEDANS and another probe (FITC) covalently attached to the operator directly revealed the essential dynamics for cooperativity in the protein–protein interaction. The ultrafast resonance energy transfer from IAEDANS in the protein to FITC also revealed different dynamic flexibility in the allosteric interaction. An attempt was made to correlate the dynamic changes in the protein dimers with O_E and O_I with the consequent protein–protein interaction (tetramerisation) to form a DNA loop encompassing the promoter segment.     

Analysis and Simulation of Second-Order Statistics with Modified Characteristic Function Parameters in a Multipath Fading Environment

In this paper, we analyse and implement a modified low pass filtering based characteristic function for a multipath Rayleigh fading channel. A new class of this modified filtering sequence based statistical simulation model is proposed for a Rayleigh fading environment. Comparing with the sum-of-sinusoids (SOS) deterministic model and its modifications as a new SOS model, the proposed model reintroduces the randomness to Doppler frequency and initial phase of the sinusoids to have non-deterministic simulators with desired statistical properties. The expressions and simulation results of level crossing rate (LCR) and average fade duration are derived and shown in this paper. Comparison of power spectra reveals that the spectrum spread is much less for our proposed method. Therefore, we would expect reduction in the rapidity of fading which is observed in LCR calculations.     

A distortion corrected single camera-based weight estimation technique for industrial objects

This paper describes a unique single camera-based dimensional measurement with a self-calibration method of image-based measurement. The system has been designed and implemented in one of the integrated steel plants in India. The purpose of the system is to obtain the frontal cross-sectional area of an ingot irrespective of its distance from the camera head. Automatic calibration is achieved by attaching a magnetic template of known area. This self-calibrating system is further refined to correct for the various distortions arising out of lens characteristics. The results obtained through field trials have been reported and found to be quite encouraging.     

Stiffness and damping coefficients of an inclined journal bearingSteifigkeit und dämpfungskoeffiziente eines schrägen gleitlagers

In the determination of the dynamic behaviour of a rotating shaft, the fluid film stiffness and damping coefficients of the bearings play an important role. The general practice is to ignore the rotational stiffnesses and damping coefficients due to the tilt of the journal in the bearing. This paper presents the stiffness and damping coefficients of such journal bearings. Using the expression for film thickness, the modified Reynolds' Equation for the tilted finite journal bearing is set up. The solution of this equation for the film pressure is obtained by using Fedor's proportionality hypothesis. The results obtained are presented in the form of non-dimensional charts.     

Quinoline–Glycomimetic Conjugates Reducing Lipogenesis and Lipid Accumulation in Hepatocytes

Nonalcoholic fatty liver disease (NAFLD), which is characterized by excess accumulation of triglyceride in hepatocytes, is the major cause of chronic liver disease worldwide and no approved drug is available. The mechanistic target of rapamycin (mTOR) complexes has been implicated in promoting lipogenesis and fat accumulation in the liver, and thus, serve as attractive drug targets. The generation of non‐ or low cytotoxic mTOR inhibitors is required because existing cytotoxic mTOR inhibitors are not useful for NAFLD therapy. New compounds based on the privileged adenosine triphosphate (ATP) site binder quinoline scaffold conjugated to glucose and galactosamine derivatives, which have significantly low cytotoxicity, but strong mTORC1 inhibitory activity at low micromolar concentrations, have been synthesized. These compounds also effectively inhibit the rate of lipogenesis and lipid accumulation in cultured hepatocytes. This is the first report of glycomimetic–quinoline derivatives that reduce lipid load in hepatocytes.