Resonance behavior of liquid bridges under axial and lateral oscillating total body forces

Cylindrical liquid bridges that are magnetically levitated in air against gravity are subjected to either axial or lateral oscillations of the total body force. It was found that the frequency of the first resonance peak is maximum when the total body force is zero and decreases with increasing total body force for both axial and lateral oscillations. The experimental results for the axially symmetric case are compared to theoretical calculations using the one-dimensional slice model.     

Multifractal analysis of drop‐casted copper (II) tetrasulfophthalocyanine film surfaces on the indium tin oxide substrates

This paper applies multifractal spectrum theory to characterize the structural complexity of 3D surface roughness of copper (II) tetrasulfophthalocyanine (CuTsPc) films on the indium tin oxide (ITO) substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films were prepared by drop cast method on ITO substrate. CuTsPc films surface roughness was studied by AFM in tapping‐mode?, in air, on square areas of 2500 µm². A novel approach, on the basis of computational algorithms for analysis of 3D roughness surface applied for AFM data, was presented. Results revealed that the 3D surface roughness of CuTsPc films prepared by drop cast method on ITO substrate can be described using the multifractal geometry. The generalized dimensions D_q and the multifractal spectrum f(α) provided quantitative values that characterize the local scale properties of CuTsPc films surface geometry at nanometer scale. Data provide valuable information to describe the spatial arrangement of 3D surface roughness of CuTsPc films on ITO substrate, which was not taken into account by classical surface statistical parameters. Copyright © 2014 John Wiley & Sons, Ltd.     

Different Heterocycles Functionalized s‐Triazine Analogues: Design,Synthesis and In Vitro Antimicrobial,Antituberculosis, and Anti‐HIV Assessment

Some new quinolone condensed s‐triazine derivatives endowed with different heterocycles and 4‐aminobenzonitrile moiety has been synthesized and examined for their bioactivities against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, and Shigella flexneri), two fungi (Aspergillus niger, Candida albicans) by using agar streak dilution method, and Mycobacterium tuberculosis H37Rv by using Lowenstein and Jensen MIC method. Upon preliminary biological screening, it was observed that the majority of the compounds were found to possess a significant broad spectrum antimicrobial (MICs: 6.25–25 µg/mL) and antitubercular (MIC: 12.5 µg/mL) potential. Hence, anti‐HIV activity against two types of HIV viral strains [HIV‐1 (III_B) and HIV‐2 (ROD)] has been carried out using the MTT assay. From this bioassay, we have identified some potent inhibitors acting as anti‐HIV‐1 agents (IC₅₀: 4.45 µg/mL) with promising therapeutic index of 16 for analogue 7 h. The structural assignments of the new products were carried out on the basis of IR, ¹H NMR, ¹³C NMR spectroscopy, and elemental analysis.     

Visual detection of arginine,histidine and lysine using quercetin-functionalized gold nanoparticles

We report on the use of quercetin-functionalized gold nanoparticles (QC-AuNPs) as a colorimetric probe for the amino acids arginine (Arg), histidine (His) and lysine (Lys). The method is based on the aggregation of the QC-AuNPs that is caused by these amino acids and leads to a visually detectable color change from red to blue. The absorption maxima shift from 525 nm to 702, 693, and 745 nm, respectively. Aggregations are confirmed by dynamic light scattering (DLS) and transmission electron microscopic techniques (TEM). The effects of the QC concentration, temperature and reaction time for the preparation of QC-Au NPs were tested. Other amino acids do not interfere. Under the optimal conditions, linear relationships exist between the absorption ratios at 702/525 nm (for Arg), 693/525 nm (for His), and 745/525 nm (for Lys) over the concentrations ranges from 2.5–1,250 μM (Arg) and 1–1,000 μM (His and Lys), respectively. The respective limits of detection are 0.04, 0.03, and 0.02 μM. The method provides a useful tool for the rapid visual and instrumental determination of the three amino acids. Figure

We report the use of quercetin as novel reagent for preparation and functionalization of gold nanoparticles to colorimetric sensing of three aminoacids (arginine, histidine and lysine). This is based on the aggregation of QC-AuNPs induced by three aminoacids.     

Metal-free diastereoselective synthesis of diaza-bicyclo[3.2.0]heptan-7-one and its transformation to functionalized proline esters

A metal-free diastereoselective synthesis of novel 4-halo-3,6-di-aryl-2,6-diaza-bicyclo[3.2.0]heptan-7-one by intramolecular endo-trig haloamination of 3-amino-2-azetidinone is reported. The amidiolytic ring opening of diaza-bicyclo[3.2.0]heptan-7-one with sodium methoxide provides an easy access to previously unknown 4-halo-3-aryl amino-pyrrolidine-2-carboxylic acid methyl esters in good yields.     

Nanosized rare earth cobaltite LaCoO<Subscript>3</Subscript> synthesized by urea combustion method

The structural, magnetic, and electrical properties of nano- and bulk samples of LaCoO₃, prepared by a urea combustion method, are investigated in this paper. The structures of phases, calcined at different temperatures, were refined in two different space groups rhombohedral R-3c and monoclinic I2/a, and a good agreement was obtained between the observed and calculated XRD patterns. Magnetic measurements reveal that the magnetic susceptibility increases with reduction in particle size. It is observed that there are two types of mechanisms which govern the conduction in different temperature ranges of these samples, and no single law of conduction fits the entire range of temperature. In high temperature range (200–300 K), Arrhenius law fits well, while in the low temperature region (100–200 K), the conduction is governed by Efros-Shklovskii’s (ES) hopping.     

Some new four-parameter potentials and their use in the study of vibrational thermodynamical quantities of diatomic molecules

Three four-parameter potentials,U _I,U _II andU _III have been proposed and their accuracy has been demonstrated by finding the mean square deviation from the true RKR potential curve for 15 electronic states of 12 diatomic molecules. Their percentage average mean square deviations from RKR curve have been found to be 1.45, 1.86 and 2.89, respectively. These compare favourably with the value 2.67 for the recently suggested four-parameter potential of Wei Hua which itself yields better results than the commonly employed three-parameter potentials. The superiority of the new potentials (especially ofU _I andU _II has been further established by using these potentials to calculate the molecular constants α_e and ω_ex_e following Dunham’s method. The corresponding percentage average mean deviations, for α_e, turn out to be 3.75, 5.13 and 15.43 and for ω_ex_e 8.73, 17.23 and 27.49, respectively, against the respective values of 7.97 and 18.88 with Wei Hua’s four-parameter potential. Also included are the values of dissociation energy determined with these potentials and these too corroborate the better performance ofU _I andU _II. The relative worth of various potential functions has been further tested by carrying out numerical study of vibrational partition function (evaluated by sum over states method), entropy and thermal capacity for the ground state of 7 molecules and comparing these with the corresponding findings based on the RKR data.     

Oxidative Bromination of Aromatic Compounds Using O-Iodoxybenzoic Acid with Tetraethylammonium Bromide

A mild and selective procedure for the bromination of activated arenes using o-iodoxybenzoic acid and tetraethylammonium bromide is presented. The reactions were carried out at room temperature and gave moderate to excellent yields.     

Highly anisotropic elasticity of a dendrimeric liquid crystal

Magnetic and electrical Freedericksz measurements were performed on the second generation monodendritic liquid crystal G₂(OH). The deduced elastic constants were found to be exceptionally anisotropic: the splay elastic constant K₁₁ is more than an order of magnitude larger than the bend elastic constant K₃₃, and the twist constant K₂₂ is approximately twice K₃₃. The results are discussed in terms of molecular conformations. Received: 23 February 1998 / Revised and Accepted: 26 May 1998     

Di(2-ethylhexyl)sulfoxide as an extractant for plutonium(IV) from nitric acid medium

The liquid-liquid extraction behavior of plutonium(IV) from aqueous nitric acid media into n-dodecane by di(2-ethylhexyl)sulfoxide (DEHSO) was investigated over a wide range of conditions. Optimum-parameters such as the aqueous phase acidity, reagent and metal concentrations, etc., were established for efficient extraction-separation of tracer as well as macro levels of plutonium. It was found that the extraction increased with increasing nitric acid concentration up to 6M HNO₃ and then decreased. Extraction also increased with increasing extractant concentration. After loading of the organic phase with 2 to 50 mg/ml of U(VI), extractability of Pu(IV) became considerably lower. Recovery of Pu(IV) from the organic phase was accomplished using dilute uranium(IV) nitrate as the strippant.