Disease-Causing Mutation in Extracellular and Intracellular Domain of FGFR1 Protein: Computational Approach

In-depth computationally based structural analysis of human fibroblast growth factor type 1 (FGFR1) protein carrying disease-causing mutation was performed in this study. Gain or loss of function due to missense mutations in FGFR1 is responsible for a variety of disorders including Kallmann syndrome, Apert syndrome, Pfeiffer syndrome, Crouzon syndrome, etc. The mutant model of the human FGFR1 protein was subjected to various in silico analysis, and most deleterious SNPs were screened out. Furthermore, docking and long molecular dynamics simulations were carried out with an intention of studying the possible impact of these mutations on the protein structure and hence its function. Analysis of various structural properties—especially of those of the functionally important regions: the extracellular immunoglobulin domain and intracellular Tyrosine kinase domain—gave some insights into the possible structural characteristics of the disease mutant and the wild-type forms of the protein. In a nutshell, compared to the wild-type protein, the mutant structures V273M and S685F are associated with significant changes, and the functionally important regions seem to adopt such structures that are not conducive for the wild-type-like functionality.     

Sol–gel synthesis and optical behavior of Mg–Ce–O nano-crystallites

The Mg–Ce–O powder are shown to contain periclase-type MgO and/or fluoride-type cerium oxide (CeO₂) depending upon the composition (x) defined by Ce/(Ce + Mg) atomic ratio. Lattice contraction of pariclase phase of MgO (average crystallite size ~8.8 nm) at Ce content of ‘x’ = 0.20 in comparison to pure MgO (crystallite size ~9.5 nm) has been realized due to oxygen vacancy formation. The optical band gap values of CeO₂ varies (3.0–3.2 eV) due to oxygen vacancy formation in CeO₂ phase, crystallite size and/or Ce³⁺/Ce⁴⁺ ratio. Further, the addition of Ce has shown to reduce the physisorption and chemisorption of water significantly as reflected by (1) suppression of related absorption peaks and (2) absence of magnesium hydroxide, Mg(OH)₂, bands in Fourier transform infrared spectra.     

Approaches for Mitigating Microbial Biofilm-Related Drug Resistance: A Focus on Micro- and Nanotechnologies

Biofilms play an essential role in chronic and healthcare-associated infections and are more resistant to antimicrobials compared to their planktonic counterparts due to their (1) physiological state, (2) cell density, (3) quorum sensing abilities, (4) presence of extracellular matrix, (5) upregulation of drug efflux pumps, (6) point mutation and overexpression of resistance genes, and (7) presence of persister cells. The genes involved and their implications in antimicrobial resistance are well defined for bacterial biofilms but are understudied in fungal biofilms. Potential therapeutics for biofilm mitigation that have been reported include (1) antimicrobial photodynamic therapy, (2) antimicrobial lock therapy, (3) antimicrobial peptides, (4) electrical methods, and (5) antimicrobial coatings. These approaches exhibit promising characteristics for addressing the impending crisis of antimicrobial resistance (AMR). Recently, advances in the micro- and nanotechnology field have propelled the development of novel biomaterials and approaches to combat biofilms either independently, in combination or as antimicrobial delivery systems. In this review, we will summarize the general principles of clinically important microbial biofilm formation with a focus on fungal biofilms. We will delve into the details of some novel micro- and nanotechnology approaches that have been developed to combat biofilms and the possibility of utilizing them in a clinical setting.     

Importance of van der Waals interaction for organic molecule-metal junctions: adsorption of thiophene on Cu(110) as a prototype

We report ab initio calculations for the interface energetics of a weakly adsorbed organic molecule on a metal surface, which serves as a model interface relevant for organic electronics. The studied thiophene ring is found to be physisorbed on the Cu(110) surface with an adsorption energy of -0.50 eV. Nonlocal correlations, i.e., van der Waals interactions, are solely responsible for the binding in this weakly interacting system, and the choice of the proper exchange-correlation function is crucially important. The adsorption of thiophene lowers the metal work function due to the formation of surface dipoles while no sizable charge transfer is found.     

Approximation of functions of Lipschitz class and solution of Fokker-Planck equation by two-dimensional Legendre wavelet operational matrix

In this paper, Lipschitz class of two-variables is considered. This is the genralization of well-known Lipschitz class of functions. A new estimator of functions belonging to generalized Lipschitz class has been obtained. Also, the solutions for the Fokker-Planck equations have been obtained for two different cases by two-dimensional Legendre wavelet operational matrix method. The approximated solutions of the time-and space-Fokker Planck equation have been compared with the exact solutions and the solutions obtained by homotopy perturbation method. The proposed scheme is simple, effective and suitable for the solution of Fokker-Planck equation.

     

Reaction of OH radical and ozone with methyl salicylate – a DFT study

A theoretical study on the reaction mechanism of methyl salicylate (MeSA), a green leaf volatile organic compound with OH radical and ozone, has been carried out using density functional theory methods using B3LYP, M06‐2X and MPW1K functionals with 6‐311++G(d,p) basis set. The atmospheric degradation pathways of MeSA with OH radical are studied under two different pathways, viz. H‐atom abstraction and electrophilic addition of OH radical. The hydrogen abstraction from –OH group is found to be the dominant reaction channel with small barrier height. Likewise, the electrophilic addition of OH radicals at the para position of MeSA is found to be favourable rather than the ortho and meta positions because of the small barrier height. However, the reaction of MeSA with respect to the addition of O₃ is initiated only through the cycloaddition to the C?C bond, resulting in primary ozonide. The Arrhenius plot for most of the addition reaction shows positive temperature dependence, while for the abstraction reaction, it exhibits negative temperature dependence over the temperature range of 278–350 K. The calculated theoretical rate constants are in good agreement with available experimental data. Overall, the addition of both OH radical and ozone possesses ability to degrade MeSA, but slower when compared with the Cl radical. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis and Characterization of Microwave Irradiation–Induced Graft Copolymerization of Methyl Methacrylate onto Delignified Grewia Optiva Fiber

Grafting of methyl methacrylate (MMA) onto delignified Grewia optiva fiber using ascorbic acid/H₂O₂ as an initiator was carried out under microwave irradiation. The effects of varying the microwave power, exposure time, and concentration of initiator and monomer of graft polymerization were studied to obtain maximum grafting percentage (26.54%). The experimental results showed that the optimal conditions for grafting were: exposure time, 10min; microwave power, 110 W; ascorbic acid concentration, 3.74mol/L × 10^?2; H₂O₂ concentration, 0.97mol/L × 10^?1; monomer concentration, 1.87mol/L × 10^?1. The graft copolymers were characterized by Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA).     

Kinetics of thermal decomposition of a synthetic K–H3O jarosite analog

The thermal decomposition kinetics of a synthetic K–H₃O jarosite analog was determined from thermogravimetric analysis at various heating rates in air. A thermal decomposition mechanism was proposed based on X-ray analysis of partially decomposed material and distinct features observed during thermal decomposition analysis. The decomposition path is complex. The material was treated as a composite of K-jarosite, H₃O-jarosite, and a “vacancy component”. The evolution of (OH)^? and SO₃ from these individual components was modeled. The decomposition is broken into subreactions according to distinct features in the thermoanalytical measurements. The subreactions are arranged sequentially and in parallel according to the evolution of the participating phases. A set of associated apparent activation energies was determined using isoconversion analysis. Kinetic triplets were assigned to each subreaction. A reasonable match with the observed decomposition was achieved by varying pre-exponential factors.     

Evaluation of K–H3O jarosite as thermal witness material

The scope of this work was the assessment of thermo-oxidative deterioration, hydrothermal stability, and crystalline zone deterioration of some bookbinding leathers from some religious books published in XVIII century stored in Romanian libraries. In this purpose, the following thermal analysis methods were employed: thermogravimetry/derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The thermo-oxidative damage of investigated leathers was characterized by the rate of the first thermo-oxidation process put in evidence in TG/DTG curves recorded in static air atmosphere. The hydrothermal stability was characterized by shrinkage temperature determined by DSC analysis of leathers in water excess. The damage of the crystalline zone of leathers was determined by DSC in nitrogen flow and DMA analyses. The qualitative damage for each leather and each kind of degradation was evaluated using the criteria resulted by thermal analysis of a large number of collagen-based materials (pure collagens, new and old parchments and leathers). The obtained results could be used for finding the best possible methods for preservation and/or restoration of the investigated bookbinding leathers.