On a class of Riemannian metrics arising from Finsler structures

On the slit tangent bundle of Finsler manifolds, we introduce a class of metrics and study the relation between Levi-Civita connection, Vaisman connection, vertical foliation, and Reinhart spaces. We show that the Levi-Civita and the Vaisman connections induce the same connections in the structural bundle if and only if the base manifold is Landsbergian. Moreover every foliated Reinhart manifold reduces to a Riemannian manifold.     

99mTc-labeling of a dithiocarbamate-DWAY fragment using [99mTcN]2+ core for the preparation of potential 5HT1A receptor imaging agents

1-(2-methoxy phenyl) piperazine fragment of WAY100635 or its phenolic analogue, derived from DWAY is used to design the desired structure of 5HT_1A receptor imaging agents. In this study a DWAY analogue was labeled with ^99mTc-nitrido ([^99mTcN]²⁺) core via dithiocarbamate. 2-(piperazin-1-yl) phenol dithiocarbamate was synthesized by the reaction of 2-(piperazin-1-yl) phenol with an equivalent amount of carbon disulfide in KOH solution then radiolabeled with ^99mTc-nitrido core. The final complex was characterized by HPLC and its radiochemical purity was more than 90 %. In vitro stability studies have shown the complex was stable at least 4 h after labeling at room temperature. The n-octanol/water partition coefficient experiment demonstrated log p = 1.34 for ^99mTcN–OHPP–DTC. Biodistribution results showed that radio tracer had moderate brain uptake (0.39 ± 0.03 %ID/g at 15 min and 0.29 ± 0.02 %ID/g at 120 min) and good retention, suggesting that this complex may lead to a further development of a radiotracer with specific binding to 5-HT_1A receptor.     

Sorption of Bi3+ from acidic solutions using nano-hydroxyapatite extracted from Persian corals

Nano-crystallite hydroxyapatite (nano-HAp) synthesized from Persian corals was used for removing Bi³⁺ from acidic aqueous solutions. The effects of initial concentration, adsorbent dosage, contact time and temperature were studied in batch experiments. The sorption of Bi³⁺ by nano-HAp increased as the initial concentration of bismuth ion increased in the medium. The pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models were applied to study the kinetics of the sorption processes. The pseudo-second-order kinetic model provided the best correlation (R ² > 0.999) of the used experimental data compared to the pseudo-first-order and intraparticle diffusion kinetic models. Various thermodynamic parameters, such as $ \Updelta G^\circ $ , $ \Updelta H^\circ $ and $ \Updelta S^\circ $ were calculated. Thermodynamics of Bi³⁺ cation sorption onto nano-HAp system pointed at spontaneous and endothermic nature of the process. The maximum Bi³⁺ adsorbed was found to be 3,333.33 mg g^?1. It was found that the sorption of Bi³⁺ on nano-HAp correlated well (R ² = 0.979) with the Langmuir equation as compared to Freundlich and Dubinin–Kaganer–Radushkevich (D-K-R) isotherm equations under the concentration range studied. This study indicated that nano-HAp extracted from Persian corals could be used as an efficient adsorbent for removal of Bi³⁺ from acidic aqueous solution.     

Trust region subproblem with an additional linear inequality constraint

This paper studies an extended trust region subproblem (eTRS) in which the trust region intersects the unit ball with a single linear inequality constraint. We present an efficient algorithm to solve the problem using a diagonalization scheme that requires solving a simple convex minimization problem. Attainment of the global optimality conditions is discussed. Our preliminary numerical experiments on several randomly generated test problems show that, the new approach is much faster in finding the global optimal solution than the known semidefinite relaxation approach, especially when solving large scale problems.     

Conformationally restricted dynamic supramolecular catalysts for substrate-selective epoxidations

A second generation of a substrate-selective dynamic supramolecular catalytic system consisting of a catalyst part and a receptor part, connected by a hydrogen-bonding motif, has been realized based on rational design. The results from analyses of the equilibrium mixture of the species generated by the components of the first generation system led us to selectively lock the cisoid conformation of the catalyst part to increase the amount of the substrate-selective catalytic cavity in the equilibrium mixture. This was realized by strapping the catalyst part by organic synthesis. This strapping led to an increase in substrate selectivity in the pair-wise competitive epoxidations of pyridyl- vs. phenyl-appended styrenes and pyridyl- vs. phenyl-appended stilbenes of both Z- and E- configuration compared to the first generation system, reaching 3.4 : 1 as the highest substrate selectivity for Z-mono-pyridyl-stilbene (27a) vs. the corresponding all-carbon analogue (28a) and for E-dipyridyl-stilbene (26b) vs. the corresponding all-carbon analogue (28b), respectively.     

An Electropolymerized Pyrrole‐based Coating for Stir Bar Sorptive Extraction of Btex from Water Followed by Gas Chromatography‐Mass Spectrometry

A stir bar sorptive extraction (SBSE) technique was developed by the use of polypyrrole (PPy) sorbent, electropolymerized on the surface of a rod, as a possible alternative to solid‐phase microextraction (SPME). Liquid desorption was subsequently employed to transfer the extracted analytes into the injection port of a gas chromatography‐mass spectrometry (GC‐MS). The PPy sorbent including polypyrrole‐dodecyl sulfate (PPy‐DS) was deposited on the surface of a stainless steel rod from the corresponding aqueous electrolyte by applying a constant deposition potential. The developed method was applied to the trace level extraction of BTEX (benzene, toluene, ethylbenzene, o,p‐xylene) from aqueous sample. Optimization of influential experimental conditions including the voltage of power supply, the time of PPy electrodeposition, the extraction temperature, the ionic strength and the extraction time were also investigated. The detection limits of the method under optimized conditions were in the range of 0.01–0.1 ng·mL?¹. The relative standard deviations (RSD) at a concentration level of 1 ng·mL?¹ were obtained between 8% and 13% (n=6). The calibration curves of BTEX showed linearity in the range of 0.03 to 600 ng·mL?¹. The proposed method was successfully applied to the extraction of some selected BTEX from river water samples and the relative recoveries were higher than 90% for all the analytes.     

Expedient one-pot synthesis of N-aryliminoethers via mild electrophilic activation of secondary amides

Abstract  

The direct transformation of various secondary amides into N-aryliminoethers via mild electrophilic activation with trifluoromethanesulfonic anhydride in the presence of 2-chloropyridine is described. Low temperature amide activation followed by warming to 0 °C and subsequent treatment with phenols provides the desired products with short overall reaction times and moderate to high reaction yields.     

The 0-Homogenous Complete Lift Metric

The complete lift of a Riemannian metric g on a differentiable manifold M is not 0-homogeneous on the fibers of the tangent bundle TM. In this paper we introduce a new kind of lift G of g, which is 0-homogeneous. It determines a pseudo-Riemannian metric on ${\widetilde {TM}}$ , which depends only on the metric g. We obtain the Levi-Civita connection of this metric and study conformal vector fields on ( ${\widetilde {TM},G}$ ). Finally, we introduce the almost product and complex structures which preserve homogeneity and study certain geometrical properties of these structures.     

Distinguished Connections on Finsler Algebroids

Considering the prolongation of a Lie algebroid,the authors introduce Finsler algebroids and present important geometric objects on these spaces.Important endomorphisms like conservative and Barthel,Cartan tensor and some distinguished connections like Berwald,Cartan,Chern-Rund and Hashiguchi are introduced and studied.