Tracking analysis of augmented complex least mean square algorithm

The augmented complex least mean‐square (ACLMS) algorithm is a suitable algorithm for the processing of both second‐order circular (proper) and noncircular (improper) signals. In this paper, we provide tracking analysis of the ACLMS algorithm in the non‐stationary environments. Using the established energy conservation argument, we derive a variance relation that contains moments that represent the effects of non‐stationary environment. We evaluate these moments and derive closed‐form expressions for the excess mean‐square error (EMSE) and mean‐square error (MSE). The derived expressions, supported by simulations, reveal that unlike the stationary case, the steady‐state EMSE, and MSE curves are not monotonically increasing functions of the step‐size parameter. We also use this observation to optimize the step‐size learning parameter. Simulation results illustrate the theoretical findings and match well with theory. Copyright © 2015 John Wiley & Sons, Ltd.     

Structural evolution and dopant occupancy preference of yttrium-doped potassium sodium niobate thin films

Sodium potassium niobate (KNN) is the most promising candidate for lead-free piezoelectric material, owing to its high Curie temperature and piezoelectric coefficients among the non-lead piezoelectric. Numerous studies have been carried out to enhance piezoelectric properties of KNN through composition design. This research studied the effects of yttrium concentrations and lattice site occupancy preference in KNN films. For this research, the yttrium-doped KNN thin films (mol% = 0, 0.1, 0.3, 0.5, 0.7 and 0.9) were fabricated using the sol-gel spin coating technique and had revealed the orthorhombic perovskite structures. Based on the replacement of Y³⁺ ions for K⁺/ Na⁺ ions, it was found that the films doped with 0.1 to 0.5 mol% of yttrium had less lattice strain, while films with more than 0.5 mol% of Y³⁺ ions had increased strain due to the tendency of Y³⁺ to occupy the B-site in the perovskite lattice. Furthermore, by analysing the vibrational attributes of octahedron bonding, the dopant occupancy at A-site and B-site lattices could be identified. O-Nb-O bonding was asymmetric and became distorted due to the B-site occupancy of yttrium dopants at high dopant concentrations of >0.5 mol%. Extra conduction electrons had resulted in better resistivity of 2.153× 10⁶ Ω at 0.5 mol%, while higher resistivity was recorded for films prepared with higher concentration of more than 0.5 mol%. The introduction of Y³⁺ improved the grain distribution of KNN structure. Further investigations indicated that yttrium enhances the surface smoothness of the films. However, at high concentrations (0.9 mol%), the yttrium increases the roughness of the surface. Within the studied range of Y³⁺ _, the film with 0.5 mol% Y³⁺ represented a relatively desirable improvement in dielectric loss, tan δ and quality factor, Q_m.     

Transient analysis of diffusion least‐mean squares adaptive networks with noisy channels

In this paper, we study the effect of noisy channels on the transient performance of diffusion adaptive network with least‐mean squares (LMS) learning rule. We first drive the update equation of diffusion LMS which incorporates the effects of noisy channels. Then, using the framework of fundamental weighted energy conservation relation, we derive closed‐form expressions for learning curves in terms of mean‐square deviation and excess mean‐square error. We also find the mean and mean‐square stability bounds of step‐size for diffusion LMS with noisy channels. We show that although noisy channels affect the performance of the diffusion LMS network, the stability bounds of the step‐size are the same form as in the ideal channels case. The derived closed‐form expressions are shown to provide a good match with values found by simulation. Copyright © 2011 John Wiley & Sons, Ltd.     

Investigating the wicking behavior of micro/nanofibrous core-sheath PET–PAN yarn modified by dimethyl 5-sodium sulfoisophthalate

The present research aims at imparting an improved wicking ability to the recycled multifilament yarns by wrapping composite nanofibers to attain an efficient material for filtration purposes. Therefore, polyacrylonitrile nanofibers containing dimethyl 5-sodium sulfoisophthalate nanoparticles were wrapped around the recycled poly(ethylene terephthalate) yarn by means of a novel electrospinning technique. Several tests were performed to investigate the parameters affecting wicking rise and moisture regain of the samples. Taguchi method was used in two separate designs (with or without nanoparticles). Some factors such as polymer solution concentration, mass ratio of nanoparticles, take-up rate, and number of filaments were considered as the variable factors while yarn wicking rate and moisture regain were the response factors. It was found that the hydrophilic nature of nanoparticles together with the ultrafine structure of nanofibers provide yarns with enhanced wicking properties. Although solution concentration is the predominant factor in wicking rate of the yarns containing nanoparticles, the most effective factor in wicking rise and moisture regain for other cases is the number of filaments. The mechanism of nanoparticle effect on fluidic jet during electrospinning process is explained by theory of nanofluids stability which has never been validated experimentally in previous research studies. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48185.     

Preparation of binary and hybrid epoxy nanocomposites containing graphene oxide and rubber nanoparticles: Fracture toughness and mechanical properties

Binary and hybrid epoxy nanocomposites modified with graphene oxide (GO) and core–shell rubbers (CSR) were synthesized via the solvent-exchange method. X-ray diffraction analysis and scanning electron microscopy of the samples showed a homogeneous dispersion of GO and CSR in the epoxy matrix. The tensile modulus and tensile strength of the samples modified with CSR decreased continuously with increasing CSR content; however, with the addition of only 0.05 phr GO to the neat epoxy and rubber-modified epoxy, these properties significantly increased. The use of GO and CSR individually improved the fracture toughness, but the impact of GO was greater. The simultaneous use of GO and CSR improved both the fracture toughness and the mechanical properties. Our investigation of the toughening mechanism indicated that crack deflection–bifurcation, crack pinning, and particle debonding–pullout in the presence of GO nanosheets and limited rubber particle cavitation contributed to fracture toughness improvement in the hybrid systems. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46988.     

In Vitro Antiamoebic Activity Evaluation and Docking Studies of Metronidazole–Triazole Hybrids

An in‐house database of 520 compounds was docked against Entamoeba histolytica thioredoxin reductase (EhTrR), a promising target for the treatment of amoebiasis. Amongst these, some metronidazole (MTZ)–triazole hybrids were ranked high, with docking scores from ?10.23 to ?7.56. Studies of the binding orientations and conformations show that the head groups of MTZ–triazole hybrids interact with the arginine residues within the binding pocket of EhTrR, making it clear that such is the optimal and most reliable orientation for this class of compounds. The top‐ten MTZ–triazole hybrids were then selected for evaluation of their activity against the HM1:IMSS strain of amoeba. The most active compound, 2‐pyridyl‐(1,2,3‐triazolyl)metronidazole 10 , with an IC₅₀ value of 8.4 nM , was significantly more active than the standard drug MTZ alone. Docking studies revealed that compound 10 may act as an EhTrR inhibitor with activity in the nanomolar range and satisfactory ADME properties; it is a suitable candidate to be carried forward as a potential lead in the discovery of drugs to combat amoebiasis.     

Polyaniline matrix containing nickel ferromagnet

Metallic nickel (Ni) was successfully dispersed onto a polyaniline (PANI) matrix by a simple one‐step electrochemical method. Ni particles as deposited onto the polymer seemed to be much smaller compared to those deposited onto bare Pt. The size of the Ni deposits was found to be influenced by the electrolytic bath composition and potential sweep rate. The PANI matrix thus dispersed with Ni particles exhibited ferromagnetic behavior and a lower electrical conductance. The decrease in conductivity may be attributed to the partial blockage of the conductive path by the Ni particles thus embedded in the polymer matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 321–327, 2006     

Terpenoids as Human Neutrophil Elastase (HNE) Inhibitors: A Comprehensive Review of Natural Anti-inflammatory Isoprenoids

Human neutrophil elastase (HNE) is an enzyme that plays a key role in the body‘s inflammatory response. It has been linked to several diseases such as chronic obstructive pulmonary disease (COPD), emphysema, and cystic fibrosis. As potential treatments for these diseases, HNE inhibitors are of great interest. Metabolites derived from plants, particularly terpenoids such as β-caryophyllene found in black pepper and other plants, and geraniol present in several essential oils, are recognized as significant sources of inhibitors for HNE. Because of their ability to inhibit HNE, terpenoids are considered promising candidates for developing novel therapies to treat inflammatory conditions such as COPD and emphysema. Furthermore, nature can serve as an excellent designer, and it may offer a safer drug candidate for inhibiting HNE production and activity in the future. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were searched to get relevant and up-to-date literature on terpenoids as human neutrophil elastase inhibitors. This review focuses on the isolation, chemical diversity, and inhibition of human neutrophil elastase (HNE) of various terpenoids reported from natural sources up to 2022. A total of 251 compounds from various terpenoids classes have been reported. Further, it also provides a summary of HNE inhibitors and includes a thorough discussion on the structure-activity relationship.     

Insights into the Influence of Work Functions of Cathodes on Efficiencies of Perovskite Solar Cells

Though various efforts on modification of electrodes are still undertaken to improve the efficiency of perovskite solar cells, attributing to the large scope of these methods, it is of significance to unveil the working principle systematically. Herein, inverted perovskite solar cells based on indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH₃NH₃PbI₃/phenyl‐C61‐butyric acid methyl ester (PC₆₁ BM)/buffer metal/Al are constructed. Through the choice of different buffer metals to tune work function of the cathode, the contact nature of the active layer with the cathode could be manipulated well. In comparison with the device using Au/Al as the electrode that shows an unfavorable band bending for conducting the excited electrons to the cathode, the one with Ca/Al presents a dramatically improved efficiency over 17.1%, ascribed to the favorable band bending at the interface of the cathode with the active layer. Details for tuning the band bending and the corresponding charge transfer mechanism are given in a systematic manner. Thus, a general guideline for constructing perovskite photovoltaic devices efficiently is provided.