The modular robotic systems

A very important design goal of these robotic systems is the adaptability to the inner diameters of the pipes. In this paper, we proposed two wheeled–type in–pipe modular robotic systems. Thus, the studied modular robotic systems are characterized by an adaptable structure, based on linkages mechanisms. The prototypes were designed in order to inspect pipes with variable diameters within 140 and 200 mm. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and cytotoxic activities of transition-metal complexes of a binaphthyl-linked bipyridine ligand

A binaphthyl-linked bipyridyl compound, 1,1′-bis(6-methyl-6′-oxymethylenyl-2,2′-bipyridine)binaphthyl, (L) has been synthesised and used as a ligand for the formation of Cu(II), Ni(II), and Co(II) complexes. The ligand and its transition-metal complexes were characterized by physico-chemical and spectroscopic methods. The complexes were also investigated for cytotoxic activity. The cytotoxicity of complexes, CuL(ClO₄)₂, NiL(ClO₄)₂(H₂O), CoL(ClO₄)₂, were tested in vitro applying seven well-characterized human tumor cell lines, MCF7, EVSA-T, WIDR, IGROV, M19 MEL, A498, H226, and the microculture sulforhodamine B (SRB) test. All complexes show a very high cytotoxicity (ID₅₀ < 250 ng/ml) in these cell lines.     

Influence of hot-carrier luminescence from avalanche photodiodes on time-correlated photon detection

We present the results of our time-resolved measurements of hot-carrier luminescence from passively quenched Geiger-mode avalanche photodiodes. In time-correlated photon-counting (TCPC) experiments, hot-carrier luminescence interferes overwhelmingly with the coincidence spectrum, which results in artifacts. This potential problem should be taken into account in setting up TCPC experiments.     

An Electrochemical Sensing Platform Based on Graphene Oxide and Molecularly Imprinted Polymer Modified Electrode for Selective Detection of Amoxicillin

An electrochemical sensing platform based on composite material, consisting of molecularly imprinted polymer coated on graphene oxide (MIP-GO), was developed for selective and sensitive analysis of amoxicillin (AMOX). The MIP-GO composite, which was fabricated by sol-gel polymerization after removal of template molecule, was deposited as a thin film on glassy carbon electrode, and then was electrochemically characterized by cyclic voltammetry and differential pulse voltammetry. The linear response for the determination of AMOX was obtained in the concentration range from 5.0×10⁻¹⁰ to 9.1×10⁻⁷ M under the most proper conditions and the detection limit was found to be 2.94×10⁻¹⁰ M.     

Adsorption of toxic metals by natural and modified clinoptilolite

The chromium, cobalt and lead removal from aqueous solution by natural and modified zeolites was examined by using a batch-type method. Clinoptilolite samples used in this study were supplied from Bigadi?, Turkey. All samples were modified with HNO3 or NaOH to improve the adsorption capacity for heavy metals. The removal efficiencies and kinetics of heavy metals such as chromium, cobalt and lead on natural and modified zeolites were determined. The effects of the initial metal concentration on the removal percentage of heavy metal ions were studied. Freundlich and Langmuir isotherm constants and correlation coefficients were found and the equilibrium process was described by the Freundlich isotherm. The adsorption kinetic was tested and then it indicates the process to be diffusion controlled.     

Determination of tianeptine in tablets by high-performance liquid chromatography with fluorescence detection

A sensitive and selective high-performance liquid chromatographic method has been developed for the determination of tianeptine (Tia) in tablets. The method is based on derivatization of Tia with 4-chloro-7-nitrobenzofurazan (NBD-CI). A mobile phase consisting of acetonitrile-10 mM orthophosphoric acid (pH 2.5; 77 + 23) was used at a flow rate of 1 mL/min on a C18 column. The Tia-NBD derivative was monitored using a fluorescence detector, with emission set at 520 nm and excitation at 458 nm. Gabapentin was selected as an internal standard. Linear calibration graphs were obtained in the concentration range of 45-300 ng/mL. The lower limit of detection (LOD) was 10 ng/mL at a signal-to-noise ratio of 4. The lower limit of quantitation (LOQ) was 45 ng/mL. The relative standard values for intra- and interday precision were <0.46 and <0.57%, respectively. The recovery of the drug samples ranged between 98.89 and 99.85%. No chromatographic interference from the tablet excipients was found. The proposed method was validated in terms of precision, robustness, recovery, LOD, and LOQ. All the validation parameters were within the acceptance range. The proposed method was applied for the determination of Tia in commercially available tablets. The results were compared with those obtained by an ultraviolet spectrophotometric method using t- and F-tests.     

Computational characterization of isomeric C4H2O systems: Thermochemistry,vibrational frequencies,and optical spectra for butatrienone,ethynyl ketene,butadiynol, and triafulvenone

Species of empirical formula C₄H₂O have been invoked either as elusive intermediates in flames or oxidations on heterogeneous catalysts, or as long‐lived species in the interstellar medium. Butatrienone has been characterized experimentally, but isomers ethynyl ketene, butadiynol, and trifulvenone have been described only by computational modeling. Triafulvenone is of special interest as the ketene analog of the carbonyl compound cyclopropenone; both species contain seriously strained three‐membered rings. In contrast to cyclopropenone, which is detected in the interstellar medium, triafulvenone continues to elude experimental capture. The contrast is attributed to a degree of aromatic stabilization in cyclopropenone and anti‐aromatic destabilization in triafulvenone. In this report, we characterize the structure, vibrational and electronic spectra, and thermochemistry for triafulvenone and three of its isomers, butatrienone, ethynyl ketene, and butadiynol to assist experimental detection of these elusive species. Our calculations have shown that triafulvenone is the least stable of these four isomers; even the well‐known butatrienone, is not the most stable. The so far undetected ethynyl ketene is thermodynamically the most stable of these isomers. To facilitate experimental detection of these species we provide vibrational frequencies calculated using both B3LYP/cc‐pVTZ and MP2/cc‐pVTZ level model chemistry corrected for anharmonicity including the possibility that the spectra may include overtones and combination bands for these species The regions of intense IR absorption and most important frequencies are also underlined for all the species involved. To guide the search for short‐lived C₄H₂O species, we also characterize the optical spectrum. © 2015 Wiley Periodicals, Inc.     

Suzuki-Miyaura reactions of N-protected tribromopyrazoles. Efficient and site-selective synthesis of 3,4,5-triaryl-pyrazoles, 3,5-diaryl-4-bromopyrazoles and 5-aryl-3,4-dibromopyrazoles

Suzuki-Miyaura reactions of N-protected tribromopyrazoles were studied. The reactions proceed with excellent site-selectivity. The first attack occurs at position 5, while the second and third attack occur at positions 3 and 4, respectively. A variety of 3,4,5-triaryl-pyrazoles, 3,5-diaryl-4-bromopyrazoles, and 5-aryl-3,4-dibromopyrazoles were efficiently prepared. The products are not readily available by other methods.     

Transformations of 2-alkylidene-4-oxothiazolidine vinyl bromides initiated by bromophilic attack of neutral and anionic nucleophiles

Vinyl bromides derived from 2-alkylidene-4-oxothiazolidines represent a class of vinyl halides, which readily undergo a bromophilic attack by a range of nucleophiles. With Ph₃P, AcS⁻, CN⁻, I⁻, F⁻, Ac₂CH⁻ and N₃⁻ the attack ends up with reductive debromination, whereas the bromine substitution takes place with KSCN. When acetate anion and organic bases, such as pyridine, Et₃N or morpholine, are employed as nucleophiles the initial bromophilic attack is followed by bromine migration to the C(5) position of the ring, allowing the C(5) functionalization of this heterocyclic system.