Vacuum-Deposited Thin Film of Aniline–Formaldehyde Condensate/WO3·nH2O Nanocomposite for NO2 Gas Sensor

A hydrated tungsten oxide (WO₃·nH₂O)-embedded aniline–formaldehyde condensate (AFC/WO₃·nH₂O) nanocomposite thin film was prepared on an indium tin oxide (ITO)-coated glass surface via vacuum-deposition technique. The resulting AFC/WO₃·nH₂O/ITO thin film was characterized using ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and electron microscopy (SEM). The composite thin film exhibited a crystalline surface morphology containing nanocrystals of WO₃·nH₂O with a diameter ranging from 15 to 20 nm. The AFC/WO₃·nH₂O/ITO film allowed for the low potential detection of NO₂ gas at a concentration range from 0 to 9000 ppm. The NO₂ gas sensing characteristics were studied by measuring the change in the current with respect to concentration and time. The current of the AFC/WO₃·nH₂O/ITO film linearly increased with an increase in concentration of NO₂ gas with a response of ~20 s.     

Hydrodynamic study on radially cross-flow fluidized bed multi-staged ion-exchange column

A hydrodynamic study was carried out on our patented radially cross-flow fluidized bed staged column, with the salt laden water and solid resins flowing counter-currently, to determine the loading/flooding criterion for a stable operation of the column, and also to ascertain the mal-distribution in flow. Residense time distribution measurements were taken to address the latter part of the study. The data collected from the hydrodynamic measurements show a wider range of liquid and solid flowrates that can be used for the stable operation of the column, in comparison to that obtained in the conventional multi-staged column. The extent of mal-distribution or channeling is also relatively smaller in the former. The observations are consistent with the mass-transfer results obtained in our recent study, where the separation of dissolved solids using the radially cross-flow ion exchange column was found to be 40% larger than that in the conventional column.     

High Temperature Sliding Wear of Spray-Formed Solid-Lubricated Aluminum Matrix Composites

The present work describes the tribological study of the aluminum metal matrix composite manufactured by the spray atomization and deposition technique. The immiscible element Sn is added in the Al-Si alloy in different proportion to see its effect on wear behavior. The economical mineral zircon sand (8 vol.%) of size range 63-90 μm has been used as ceramic reinforcement. The microstructural features showed that Sn and reinforced particles were homogeneously dispersed in the matrix phase. The wear experiments were conducted at high temperature on pin-on-disk wear testing machine. The wear debris and worn surfaces are analyzed with the help of scanning electron microscope equipped with energy-dispersive spectroscopy facility. The Al-Si-10Sn/ZrSiO₄ composite offers higher wear resistance as compared to base alloy and other composites irrespective of the high temperature conditions of wear tests.     

Microstructure characterization and charpy toughness of P91 weldment for as-welded,post-weld heat treatment and normalizing & tempering heat treatment

The effect of weld groove design and heat treatment on microstructure evolution and Charpy toughness of P91 pipe weldments was studied. The P91 pipe weldments were subjected to subcritical post weld heat treatment (760 °C-2 h) and normalizing/tempering conditions (normalized-1040 °C/40 min, air cooled; tempered 760 °C/2 h, air cooled) were employed. The influence of subsequent PWHT and N&T treatment on the microstructure of various zone of P91 pipe weldments were also investigated. The present investigation also described the effect of PWHT and N&T treatment on hardness, grain size, precipitate size, inter-particle spacing and fraction area of precipitates present in each zone of P91 pipe weldments. The result indicated great impact of heat treatment on the Charpy toughness and microstructure evolution of P91 weldments. The N&T treatment was found to be more effective heat treatment compared to subsequent PWHT. Charpy toughness value was found to be higher for narrow-groove design as compared to conventional V-groove design.     

Reduction of hexavalent chromium by Bacillus sp. isolated from chromite mine soils and characterization of reduced product

BACKGROUND: The reduction of highly mobile and toxic hexavalent chromium by bacterial strains is considered to be a viable alternative to reduce Cr(VI) contamination, in soils and water bodies, emanating from the overburden dumps of chromite ores and mine drainage. The present study reports the isolation of Cr(VI) resistant bacterial strains from an Indian chromite mine soil and their potential use in reduction of hexavalent chromium. RESULTS: Among the isolates, a bacterial strain (CSB‐4) was identified as Bacillus sp. based on standard biochemical tests and partial 16SrRNA gene sequencing, which was tolerant to as high as 2000 mg L^?1 Cr(VI) concentration. The strain was capable of reducing Cr(VI) to Cr(III) in different growth media. Under the optimized conditions pH ～7.0, 100 mg L^?1 Cr(VI), 35 °C temperature and stirring speed 100 rpm, CSB‐4 reduced more than 90% of Cr(VI) in 144 h. The time course reduction data fitted well an exponential rate equation yielding rate constants in the range 3.22 × 10^?2 to 6.5 × 10^?3 h^?1 for Cr(VI) concentration of 10–500 mg L^?1. The activation energy derived from temperature dependence rate constants between 25 and 35 °C was found to be 99 kJ mol^?1. The characterization of reduced product associated with bacterial cells by SEM‐EDS, FT‐IR and XRD was also reported. CONCLUSION: Reasonably high tolerance and reduction ability of indigenous Bacillus sp. (CSB‐4) for Cr(VI) under a wide range of experimental conditions show promise for its possible use in reclamation of chromite ore mine areas including soils and water bodies. Copyright © 2010 Society of Chemical Industry     

Studies of dielectric relaxation and a.c. conductivity in [(100−<Emphasis Type="Italic">x</Emphasis>)PEO + <Emphasis Type="Italic">x</Emphasis>NH<Subscript>4</Subscript>SCN]: Al-Zn ferrite nano composite polymer electrolyte

Present work deals with findings on dielectric behaviour and a.c. conduction in a ferrite doped polymer nano composite electrolyte system, namely [(100−x) PEO + xNH₄SCN]: ferrite. The formation of nano composite and structural behavior of electrolyte was studied by XRD and SEM images. The effect of salt and ferrite on conductivity behaviour of PEO based nano composite polymer electrolyte has been investigated by the impedance spectroscopy at room temperature. The variation of dielectric permittivity and dielectric loss with frequency was carried out at ambient temperature. The a.c. conductivity seems to follow the universal power law.     

Organofluorine Hydrazone Derivatives as Multifunctional Anti-Alzheimer's Agents with CK2 Inhibitory and Antioxidant Features

A set of novel hydrazone derivatives were synthesized and analyzed for their biological activities. The compounds were tested for their inhibitory effect on the phosphorylating activity of the protein kinase CK2, and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the DPPH, ABTS and peroxyl radicals. Several compounds have been identified as good antioxidants as well as potent protein kinase CK2 inhibitors. Most hydrazones containing a 4-N(CH₃)₂ residue or perfluorinated phenyl rings showed high activity in the radical-scavenging assays and possess nanomolar IC₅₀ values in the kinase assays.     

Identification of Natural Products as Potential Pharmacological Chaperones for Protein Misfolding Diseases

Defective protein folding and accumulation of misfolded proteins is associated with neurodegenerative, cardiovascular, secretory, and metabolic disorders. Efforts are being made to identify small-molecule modulators or structural-correctors for conformationally destabilized proteins implicated in various protein aggregation diseases. Using a metastable-reporter-based primary screen, we evaluated pharmacological chaperone activity of a diverse class of natural products. We found that a flavonoid glycoside ( C-10 , chrysoeriol-7-O-β-D-glucopyranoside) stabilizes metastable proteins, prevents its aggregation, and remodels the oligomers into protease-sensitive species. Data was corroborated with additional secondary screen with disease-specific pathogenic protein. In vitro and cell-based experiments showed that C-10 inhibits α-synuclein aggregation which is implicated in synucleinopathies-related neurodegeneration. C-10 interferes in its structural transition into β-sheeted fibrils and mitigates α-synuclein aggregation-associated cytotoxic effects. Computational modeling suggests that C-10 binds to unique sites in α-synuclein which may interfere in its aggregation amplification. These findings open an avenue for comprehensive SAR development for flavonoid glycosides as pharmacological chaperones for metastable and aggregation-prone proteins implicated in protein conformational diseases.     

Structure-Activity Relationship Explorations and Discovery of a Potent Antagonist for the Free Fatty Acid Receptor 2

Free fatty acid receptor 2 (FFA2) is a sensor for short-chain fatty acids that has been identified as an interesting potential drug target for treatment of metabolic and inflammatory diseases. Although several ligand series are known for the receptor, there is still a need for improved compounds. One of the most potent and frequently used antagonists is the amide-substituted phenylbutanoic acid known as CATPB ( 1 ). We here report the structure-activity relationship exploration of this compound, leading to the identification of homologues with increased potency. The preferred compound 37 (TUG-1958) was found, besides improved potency, to have high solubility and favorable pharmacokinetic properties.     

Proton Nuclear Magnetic Resonance-Based Method for the Quantification of Epoxidized Methyl Oleate

Epoxidized methyl esters (EMO) with their high oxirane ring reactivity, acts as a raw material in the synthesis of various industrial chemicals including polymers, stabilizers, plasticizers, glycols, polyols, carbonyl compounds, biolubricants etc. EMO has been generally quantified by the gas chromatography (GC) and high-performance liquid chromatography (HPLC) techniques. Taking into the account of the limitations of these techniques, two qHNMR-based equations have been proposed for the quantification of EMO in the mixture of EMO and methylesters (MO). The validity of the proposed method was determined using standard mixtures of MO and EMO having different molar concentrations. The developed equations have been applied on the samples of EMO prepared from oleic acid in two-step process viz., esterification followed by epoxidation. The qHNMR-based EMO quantification showed acceptable agreement with the results obtained from HPLC analysis.