Mo<Subscript>6</Subscript>Cl<Subscript>12</Subscript>-Incorporated Sol-Gel for Oxygen Sensing Applications

Excitation of hexanuclear molybdenum complexes such as Mo₆Cl₁₂ and its derivatives in the ultraviolet results in a strongly red-shifted luminescence centered at 750nm. Since oxygen efficiently quenches the luminescence, these thermally stable inorganic complexes are candidate lumophores for real-time, high temperature optical fiber based sensing of oxygen. Sol-gel films containing the acetonitrile complex of Mo₆Cl₁₂ were deposited on quartz substrates by dip coating. After drying, the films were heated at 200^∘C for 1 h. The luminescence lineshapes of films before and after heating were unchanged, indicating that heating did not adversely affect the cluster photophysics. Compared to solutions of the acetonitrile complex, quenching by oxygen was smaller in the as-prepared films, but heating at 200^∘C for 1 h increased the quenching, apparently due to increased oxygen permeability resulting from the loss of water or other small molecules from the matrix. These results confirm the potential of hexanuclear molybdenum complexes such as Mo₆Cl₁₂⋅2CH₃CN as the lumophores in fiber optic oxygen sensors that can operate up to 200^∘C.     

α-Trifluoromethyl vinyl acetate. II

Low conversion, low molecular weight homopolymers of α-trifluoromethyl vinyl acetate have been obtained by pyridine initiation and also by employing very large amounts of benzoyl peroxide. Since allylic hydrogens are not present, it appears that the limiting factor in the polymerization of isopropenyl esters is a slow rate of chain growth rather than degradative chain transfer. Copolymerization of the fluoromonomer (M₂) with vinyl acetate (M₁) yields values of r₁ = 0.25 and r₂ = 0.20, and for the fluoromonomer values of 0.069 and 1.51, respectively, for Q and e. Whereas ultraviolet initiation of equimolar mixtures of α-trifluoromethyl vinyl acetate and vinyl acetate yields low molecular weight copolymers, diisopropyl percarbonate-initiated room temperature bulk copolymerizations and emulsion copolymerizations yield polymers of high DP . Differential thermal analysis of an equimolar copolymer of vinyl acetate and the fluoromonomer surprisingly yields a sharp endotherm reminiscent of crystalline polymers. The unhydrolyzed copolymers in acetone and the alcoholyzed copolymers in 0.1N alkali exhibit Huggins k′ values of 0.3–0.4. Like ordinary poly(vinyl alcohol), the polyfluoroalcohols lose viscosity in dilute alkali due to retrograde aldol condensations. The solubilities of the polyfluoroalcohols, together with their thermal behavior, NMR spectrum, polarized infrared spectrum, refractive index, abilities to form visible polarizers, and other properties are also described.     

Electrochemically Surface-modified Aluminum Electrode Enabling High Performance and Ultra-long Cycling Life Al-ion Batteries

Innovation in electronic devices has created a demand for energy storage systems. Recently, rechargeable Al-ion batteries (AIBs) have received significant attention owing to their high gravimetric capacity and low cost. In this study, the electrochemical performances of pristine, etched, and electropolished Al negative electrodes via surface modification were investigated to determine their efficiency in AIBs. Herein, pristine, etched, and electropolished Al acted as the negative electrodes (anodes), and pure graphite and aluminum chloride (AlCl₃)/1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) were used as the positive electrode (cathode) and ionic liquid electrolyte, respectively. This new type of electropolished Al-based battery cell shows good cyclability and high performance compared to pristine and etched Al electrodes. The electropolished Al electrode stabilized at an average capacity of 50 mAh g⁻¹ over 10,000 cycles at an ultrafast current rate of 5,000 mA g⁻¹.     

An inclusive SUSY approach to position dependent mass systems

The supersymmetry (SUSY) formalism for a position dependent mass problem with a more general ordering is yet to be formulated. In this paper, we present an unified SUSY approach for PDM problems of any ordering. Highlighting all non-Hermitian Hamiltonians of PDM problems are of quasi-Hermitian nature, the SUSY operators of these problems are constructed using similarity transformation. The methodology that we propose here is applicable for even more general cases where the kinetic energy term is represented by linear combination of infinite number of possible orderings. We illustrate the method with an example, namely Mathews-Lakshmanan (ML) oscillator. Our results show that the latter system is shape invariant for all possible orderings. We derive eigenvalues and eigenvectors of this nonlinear oscillator for all possible orderings including Hermitian and non-Hermitian ones.     

Fougerite FeII − III oxyhydroxycarbonate in environmental chemistry and nitrate reduction

The identification of the fougerite mineral responsible for the bluish-green shade of gleysols in aquifers as being the Fe^II???III oxyhydroxycarbonate $\text{GR}(\text{CO}_{3}^{2-})^*$ of formula, $[\text{Fe}^{\rm II}_{6x}\text{Fe}^{\rm III}_{6(1 - x)}\text{O}_{12}\text{H}_{2(7-3x)}]^{2+}\bullet[\text{CO}_{3}^{2-}\bullet3\text{H}_{2}\text{O}]^{2-}$ where the ferric molar ratio x = [Fe^III/Fe_total] is restricted to the domain [1/3–2/3] induces to study the reactivity of the synthetic green rust for reducing some major pollutants. The oxidation within the solid compound $\text{GR}(\text{CO}_{3}^{2-})^*$ in the presence of nitrates is followed by miniaturized Mössbauer spectrometer (MIMOS). Ratio x = [Fe^III/Fe_total] increases up to 0.67 where $\text{GR}(\text{CO}_{3}^{2-})^*$ transforms gradually into magnetite. This could well explain the composition variability of fougerite occurrences.     

Theoretical studies on the electronic and optoelectronic properties of [A.2AP(w)/A*.2AP(WC)/C.2AP(w)/C*.2AP(WC)/C.A(w)/C*.A(WC)]–Au8 mismatch nucleobase complexes

The electronic and optoelectronic properties of [A.2AP(w)/A^*.2AP(WC)/C.2AP(w)/C^*.2AP(WC)/C.A(w)/ C^*.A(WC)]–Au₈ metal-mismatch nucleobase complexes are investigated by means of density functional theory and time-dependent methods. We selected these mispairs as 2-aminopurine (2AP) produces incorporation errors when binding with cytosine (C) into the wobble (w) C·2AP(w) mispair, and is tautomerised into Watson–Crick (WC)-like base mispair C^*·2AP(WC) and less effectively produces A.2AP(w)/A^*.2AP(WC) mispairs. The vertical ionisation potential, vertical electron affinity, hardness and electrophilicity index of these complexes have also been discussed. The modifications of energy levels and charge density distributions of the frontier orbitals are also analysed. The absorption spectra of these complexes lie in the visible region, which suggests their application in fluorescent-bio imaging. The mechanism of cooperativity effect is studied by molecular orbital potential (MEP), atoms-in-molecules (AIM) and natural bond orbital analyses. Most metalated pairs have smaller HOMO–LUMO band gaps than the isolated mismatch nucleobases which suggest interesting consequences for electron transfer through DNA duplexes.     

The automatic liquid nitrogen filling system for GDA detectors

An indigenously developed automatic liquid nitrogen (LN2) filling system has been installed in gamma detector array (GDA) facility at Nuclear Science Centre. Electro-pneumatic valves are used for filling the liquid nitrogen into the high purity germanium detector cryostat. The temperature of the out-flowing gas/liquid from the cryostat is monitored using platinum resistor thermometer. The program allows for automatic filling at regular intervals with temperature monitoring from a remote terminal.     

Titanium Nanorods Loaded PCL Meshes with Enhanced Blood Vessel Formation and Cell Migration for Wound Dressing Applications

Proper management of nonhealing wounds is an imperative clinical challenge. For the effective healing of chronic wounds, suitable wound coverage materials with the capability to accelerate cell migration, cell proliferation, angiogenesis, and wound healing are required to protect the healing wound bed. Biodegradable polymeric meshes are utilized as effective wound coverage materials to protect the wounds from the external environment and prevent infections. Among them, electrospun biopolymeric meshes have got much attention due to their extracellular matrix mimicking morphology, ability to support cell adhesion, and cell proliferation. Herein, electrospun nanocomposite meshes based on polycaprolactone (PCL) and titanium dioxide nanorods (TNR) are developed. TNR incorporated PCL meshes are fabricated by electrospinning technique and characterized by scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy (FTIR) analysis, and X‐Ray diffraction (XRD) analysis. In vitro cell culture studies, in ovo angiogenesis assay, in vivo implantation study, and in vivo wound healing study are performed. Interestingly, obtained in vitro and in vivo results demonstrated that the presence of TNR in the PCL meshes greatly improved the cell migration, proliferation, angiogenesis, and wound healing. Owing to the above superior properties, they can be used as excellent biomaterials in wound healing and tissue regeneration applications.     

Natural Dyes from Ornamental Plants as Sensitizers for Dye-Sensitized Solar Cells (DSSCs): A Review on the Structure-Activity Relationships (SARs) between Power Conversion Efficiencies and Chemical Constituents

Russian Journal of Applied Chemistry - Among the various types of solar cells, the dye-sensitized solar cells (DSSCs) are a type of thin-film solar photovoltaic cells that have been the subject of...