Preparation of indium sulfide thin films by spray pyrolysis using a new precursor indium nitrate

Indium nitrate and thiourea were used as the precursor solutions for preparing indium sulfide thin films using Chemical Spray Pyrolysis (CSP) technique. Films having various In/S ratios were characterized using X-Ray Diffraction (XRD), Energy Dispersive X-ray Analysis (EDX), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), optical absorption, transmission and photosensitivity measurements. Sample having In/S ratio 2/3 showed better crystallinity with band gap 2.66 eV. Depth profile of the sample also indicated the formation of indium sulfide. It was also observed that In/S ratio in the initial precursor solution determined the composition as well as electrical properties of the films. Maximum photosensitivity was observed for the sample prepared using solution having In/S ratio 2/4.     

Sample Treatment Approaches for Trace Level Determination of Cesium in Hepatitis B Vaccine by Suppressed Ion Chromatography

The hepatitis B surface antigen manufactured by recombinant DNA technology is extracted from the culture media by density gradient centrifugation using cesium salts. Cesium is considered to be toxic, because it affects active ion transport by blocking potassium channels. The residual trace levels of cesium in hepatitis B vaccine samples are determined by suppressed ion chromatography. Hepatitis B vaccines contain various buffer salts, aluminum-containing adjuvants, proteins and traces of iron. The polyvalent cations (Al³⁺, Fe³⁺) and proteins degrade the chromatographic performance in terms of decreased retention time and poor reproducibility. Different sample preparation approaches were evaluated with the aim of eliminating these foulants: (1) filtration, (2) digestion and (3) digestion-protein precipitation. Quantitative elimination of these foulants was achieved in the digestion-protein precipitation sample clean-up approach. Cesium was separated on the IonPac CS17 column with suppressed conductivity detection. The results of the ion chromatography (IC) method were compared with ICP-MS analysis. The precision of determination was better than 6.5% (relative standard deviation) with a method detection limit of 45 ng mL⁻¹. The expanded uncertainty in the measurement at 95% confidence level (coverage factor 2) is better than 16.3%.

     

Modified Kirchhoff's theory of plates including transverse shear deformations

A primary flexure problem defined by Kirchhoff theory of plates in bending is considered. Significance of auxiliary function introduced earlier in the in-plane displacements in resolving Poisson-Kirchhoff's boundary conditions paradox is reexamined with reference to reported sixth order shear deformation theories, in particular, Reissner's theory and Hencky's theory. Sixth order modified Kirchhoff's theory is extended here to include shear deformations in the analysis.     

Radical Compatibility with Nonaqueous Electrolytes and Its Impact on an All‐Organic Redox Flow Battery

Nonaqueous redox flow batteries hold the promise of achieving higher energy density because of the broader voltage window than aqueous systems, but their current performance is limited by low redox material concentration, cell efficiency, cycling stability, and current density. We report a new nonaqueous all‐organic flow battery based on high concentrations of redox materials, which shows significant, comprehensive improvement in flow battery performance. A mechanistic electron spin resonance study reveals that the choice of supporting electrolytes greatly affects the chemical stability of the charged radical species especially the negative side radical anion, which dominates the cycling stability of these flow cells. This finding not only increases our fundamental understanding of performance degradation in flow batteries using radical‐based redox species, but also offers insights toward rational electrolyte optimization for improving the cycling stability of these flow batteries.     

An investigation of the electron density of a Jahn–Teller‐distorted CrII cation: the crystal structure and charge density of hexakis(acetonitrile‐κN)chromium(II) bis(tetraphenylborate) acetonitrile disolvate

In the crystal structure of the title homoleptic Cr^II complex, [Cr(CH₃CN)₆](C₂₄H₂₀B)₂·CH₃CN, the [Cr(CH₃CN)₆]²⁺ cation is a high‐spin d⁴ complex with strong static, rather than dynamic, Jahn–Teller distortion. The electron density of the cation was determined by single‐crystal X‐ray refinements using aspherical structure factors from wavefunction calculations. The detailed picture of the electronic density allowed us to assess the extent and directionality of the Jahn–Teller distortion of the Cr^II cation away from idealized octahedral symmetry. The topological analysis of the aspherical d‐electron density about the Cr^II cation showed that there are significant valence charge concentrations along the axial Cr—N axes. Likewise, there were significant valence charge depletions about the Cr^II cation along the equatorial Cr—N bonds. These charge concentrations are in accordance with a Jahn–Teller‐distorted six‐coordinate complex.     

Water-dispersible sugar-coated iron oxide nanoparticles. An evaluation of their relaxometric and magnetic hyperthermia properties

Synthesis of functionalized magnetic nanoparticles (NPs) for biomedical applications represents a current challenge. In this paper we present the synthesis and characterization of water-dispersible sugar-coated iron oxide NPs specifically designed as magnetic fluid hyperthermia heat mediators and negative contrast agents for magnetic resonance imaging. In particular, the influence of the inorganic core size was investigated. To this end, iron oxide NPs with average size in the range of 4-35 nm were prepared by thermal decomposition of molecular precursors and then coated with organic ligands bearing a phosphonate group on one side and rhamnose, mannose, or ribose moieties on the other side. In this way a strong anchorage of the organic ligand on the inorganic surface was simply realized by ligand exchange, due to covalent bonding between the Fe(3+) atom and the phosphonate group. These synthesized nanoobjects can be fully dispersed in water forming colloids that are stable over very long periods. Mannose, ribose, and rhamnose were chosen to test the versatility of the method and also because these carbohydrates, in particular rhamnose, which is a substrate of skin lectin, confer targeting properties to the nanosystems. The magnetic, hyperthermal, and relaxometric properties of all the synthesized samples were investigated. Iron oxide NPs of ca. 16-18 nm were found to represent an efficient bifunctional targeting system for theranostic applications, as they have very good transverse relaxivity (three times larger than the best currently available commercial products) and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The results have been rationalized on the basis of the magnetic properties of the investigated samples.     

On Partitioning the Edge Set of a Graph into Internally Disjoint Paths without Exterior Vertices

A collection of nontrivial paths in a graph G is called a path pile of G, if every edge of G is on exactly one path and no two paths have a common internal vertex. The least number that can be the cardinality of a path pile of G is called the path piling number of G. It can be shown that ε ≤ ν + η where ε, ν and η are respectively the size, the order and the path piling number of G. In this note we characterize structurally the class of all graphs for which the equality of this relation holds.