Improved antifouling of anion-exchange membrane by polydopamine coating in electrodialysis process

The fouling, in particular the organic fouling of anion exchange membranes (AEMs), is a serious problem in electrodialysis (ED). In this paper, we attempted to improve the antifouling potential of AEM by surface modification with polydopamine (PDA). The antifouling potential was evaluated by the transition time, i.e. the time elapsed before fouling took place, using sodium dodecyl benzene sulfonate (SDBS) as a model foulant. The negative surface charge density, hydrophilicity and roughness of the membrane surface were increased with increasing dopamine concentration in the modification solution. The increases in negative surface charge density and hydrophilicity increased the antifouling potential, while the increase in surface roughness decreased the antifouling potential. Consequently, the optimum modification condition was the immersion into a 0.1 kg/m³ dopamine aqueous solution at pH 8.8 for 24 h. Under this condition, the antifouling potential of AEM was sufficiently improved. It was shown by theoretical analysis of the fouling data that the surface modification with PDA prevented the adsorption of SDBS micelles and improved the antifouling potential. Furthermore, it was experimentally confirmed that the modified membrane was highly stable.     

Adventitious sounds identification and extraction using temporal-spectral dominance-based features

Respiratory sound (RS) signals carry significant information about the underlying functioning of the pulmonary system by the presence of adventitious sounds (ASs). Although many studies have addressed the problem of pathological RS classification, only a limited number of scientific works have focused on the analysis of the evolution of symptom-related signal components in joint time-frequency (TF) plane. This paper proposes a new signal identification and extraction method for various ASs based on instantaneous frequency (IF) analysis. The presented TF decomposition method produces a noise-resistant high definition TF representation of RS signals as compared to the conventional linear TF analysis methods, yet preserving the low computational complexity as compared to those quadratic TF analysis methods. The discarded phase information in conventional spectrogram has been adopted for the estimation of IF and group delay, and a temporal-spectral dominance spectrogram has subsequently been constructed by investigating the TF spreads of the computed time-corrected IF components. The proposed dominance measure enables the extraction of signal components correspond to ASs from noisy RS signal at high noise level. A new set of TF features has also been proposed to quantify the shapes of the obtained TF contours, and therefore strongly, enhances the identification of multicomponents signals such as polyphonic wheezes. An overall accuracy of 92.4±2.9% for the classification of real RS recordings shows the promising performance of the presented method.     

Synthesis of LiMn2O4 from a gelled ovalbumin matrix

A simple and inexpensive route for the preparation of LiMn₂O₄ using ovalbumin (egg white) as a gelating agent is described. Gelation of freshly extracted ovalbumin was effected by changes in ionic strength brought about by the addition of nitrate precursors to an aqueous solution of ovalbumin and subsequent warming. This resulted in tiny pockets of precursor materials getting trapped in the matrix of the gelled ovalbumin. Heat treatment of the gelled mass yielded submicron-sized LiMn₂O₄ crystals at temperatures as low as 400 °C.     

Yield locus studies of oriented polycarbonate An anisotropic and pressure-dependent solid

Uniaxial and biaxial stress states were employed so as to investigate the yield behavior of oriented polycarbonate. These experimental results are compared with a theoretical yield locus based upon a yield criterion proposed for solids that are both anisotropic and pressure dependent in regard to macroscopic yield behavior. A good correlation between theory and experiment was found.     

The macroscopic yield behaviour of polymers

A yield criterion, not previously compared with the actual macroscopic behaviour of polymers, is herein compared with the pressure-modified octahedral shear stress criterion earlier suggested by others. This new relation, which is a version of the von Mises criterion, accommodates differences in tensile and compressive yield strengths and accounts for any dependence of yielding on the hydrostatic component of the applied stress state.With the use of thin-wall tubes accounting for the majority of experimental points, the yield behaviour of polycarbonate and polyvinylchloride was investigated. Besides these findings, results previously reported by others have also been utilized in this paper. Since these various studies employed quite different polymers, the excellent overall correlation of experiment with prediction should merit the serious attention of persons interested in the macroscopic yield behaviour of polymers.Comparisons between this new criterion and the modified octahedral shear stress are also made in regard to the effect of pressure on subsequent yield behaviour. Although not fully verified, it is suggested that the predictions which result using this new criterion, seem a little more reasonable.     

Poly(ethylene-co-vinyl acetate)/calcium phosphate nanocomposites: contact angle, diffusion and gas permeability studies

Poly(ethylene-co-vinyl acetate) (EVA) based nanocomposites were prepared by melt mixing in an internal mixer with nanoparticles of calcium phosphate. Contact angle measurements of the composites with water and methylene iodide were measured. Parameters such as total solid surface free energy, work of adhesion, interfacial free energy and spreading coefficient were calculated. The interaction parameter between the polymer and the liquid has been calculated using Girifalco-Good’s equation. Water diffusion studies of the composites were done at two different temperatures, 27 °C and 50 °C to know the solvent uptake behaviour. Water diffusion showed remarkable reduction with respect to the filler content. Gas permeability studies with oxygen and nitrogen also showed improvement in barrier properties for the composites.     

Evidences for diabetes and insulin mimetic activity of medicinal plants: Present status and future prospects

Diabetes mellitus (DM) is a considerable systemic metabolic disorder to exhibit various metabolic and cardiovascular disorders, mainly hyperglycemia. The global projected estimate of diabetes in 2030 will be about 439 million adults, out of which 300 million expected are of type-2 diabetes mellitus (T2DM). The present knowledge revealed responsible factors, occurrence and mechanism of these factors involved in the DM diseases. Hence, the aim of this review is to address and summarize the causes, plant resources, importance, present status and future programmes for diabetes control. The present review answers the contemporary present questions raised in the scientific field on DM. Two major problems are explained in detail about the autoimmune attack or dysfunction of β-cell and insulin resistance involved for Type 1 and Type 2 DM, respectively. Though there are various approaches to reduce the ill effects of diabetes and its secondary complications, many preferred herbal formulations due to lesser side effects and low cost. For this reason still it is getting increased attention in searching antidiabetic medicinal plants for hot research and to develop targeted medicine. Recurrence of islet autoimmunity lesson from pancreatic islet cell transplantation to cure T1D was outlined. With these highlights, the review summarizes the current knowledge on diabetes occurrence, factors (environmental and genetics), and types (I, II, gestation, and secondary DM), antidiabetic plants, sources for insulin mimetic plant principle compounds and their target mechanism with current and future trusted research areas for controlling of DM.