Cu (II) Chemosensor Based on a Fluorogenic Bodipy-Salophen Combination: Sensitivity and Selectivity Studies

A new fluorescent chemosensor (Bodipy-S) derived from Bodipy and Salophen was developed. After the characterization of all compounds, the behavior of the chemosensor Bodipy-S toward p, d and f block-metal ions was investigated by UV-vis and fluorescence spectroscopy. This chemosensor can selectively detect to Cu (II) in methanol-aqueous solution based on chelation enhanced fluorescence (CHEF) and it almost exhibit to a fluorescence quenching effect with 20-fold. The binding constant of the fluorophore was interpreted by using of the Stern-Volmer method and the complex stoichiometry was defined by using Job’s plot. Moreover, the effect of pH was performed by the fluorescence intensities of Bodipy-S in presence of Cu(II) ions. The chemosensor can be successfully used to the detection of Cu(II) in most areas.     

Triethylamin-mediated addition of 2-aminoethanethiol hydrochloride to chalcones: Synthesis of 3-(2-aminoethylthio)-1-(aryl)-3-(thiophen-2-yl) propan-1-ones and 5,7-diaryl-2,3,6, 7-tetrahydro-1,4-thiazepines

The triethylamin-mediated addition of 2-aminoethanethiol hydrochloride to chalcone analogs was investigated. This addition, bearing a 2-thienyl group at the 3-position, gave the only addition adduct at room temperature in 3 h, whereas the chalcones bearing the 2-furyl group at the 1-position gave an addition-cyclization product (1, 4-thiazepine) in the same conditions. The effect of the groups to the reaction was investigated by changing the 1- and 3-position groups. The chalcones bearing the 2-thienyl group at the 1-position and the others afforded the mixture of products in different ratio at rt for 0.5–24 h. Moreover, the addition–cyclization products (1,4-thiazepine) were obtained under reflux conditions in 36 h. The structures of the synthesized compounds were elucidated by ¹H NMR, ¹³C NMR, infrared, and elemental analysis.     

Ultrafast dynamics and anionic active states of the flavin cofactor in cryptochrome and photolyase

We report here our systematic studies of the dynamics of four redox states of the flavin cofactor in both photolyases and insect type 1 cryptochromes. With femtosecond resolution, we observed ultrafast photoreduction of oxidized state flavin adenine dinucleotide (FAD) in subpicosecond and of neutral radical semiquinone (FADH(*)) in tens of picoseconds through intraprotein electron transfer mainly with a neighboring conserved tryptophan triad. Such ultrafast dynamics make these forms of flavin unlikely to be the functional states of the photolyase/cryptochrome family. In contrast, we find that upon excitation the anionic semiquinone (FAD(*-)) and hydroquinone (FADH(-)) have longer lifetimes that are compatible with high-efficiency intermolecular electron transfer reactions. In photolyases, the excited active state (FADH(-)*) has a long (nanosecond) lifetime optimal for DNA-repair function. In insect type 1 cryptochromes known to be blue-light photoreceptors the excited active form (FAD(*-)*) has complex deactivation dynamics on the time scale from a few to hundreds of picoseconds, which is believed to occur through conical intersection(s) with a flexible bending motion to modulate the functional channel. These unique properties of anionic flavins suggest a universal mechanism of electron transfer for the initial functional steps of the photolyase/cryptochrome blue-light photoreceptor family.     

Recent progress in pillar[n]arene-based thin films on chemical sensor applications

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Pillar[n]arene is one of the most favorited supramolecular materials that possess a special chiral structure. The major property of...     

One-Parameter Plane Hyperbolic Motions

Müller [3], in the Euclidean plane , introduced the one parameter planar motions and obtained the relation between absolute, relative, sliding velocities (and accelerations). Also, Müller [11] provided the relation between the velocities (in the sense of Complex) under the one parameter motions in the Complex plane . Ergin [7] considering the Lorentzian plane , instead of the Euclidean plane , and introduced the one-parameter planar motion in the Lorentzian plane and also gave the relations between both the velocities and accelerations. In analogy with the Complex numbers, a system of hyperbolic numbers can be introduced: . Complex numbers are related to the Euclidean geometry, the hyperbolic system of numbers are related to the pseudo-Euclidean plane geometry (space-time geometry), [5,15]. In this paper, in analogy with Complex motions as given by Müller [11], one parameter motions in the hyperbolic plane are defined. Also the relations between absolute, relative, sliding velocities (and accelerations) and pole curves are discussed.      

一个解剖基人体下肢的生物动力模型--第二部分: 数值结果

表述人体下肢生物动力模型的数值技术、数值结果并将其与文献进行比较.模型显示:当人体下肢小腿受冲击外载荷作用时,在膝关节处所产生的4个主要韧带张力以及膝关节处的咬合接触力,在大腿固定不动(或运动受到约束)的情况下,要远大于大腿未受约束的情形.这与医学常识是吻合的.     

一个解剖基人体下肢的生物动力模型--第一部分: 模型描述

建立一个完整的解剖基人体下肢二维（矢状面内）生物动力模型,该模型仿真了人体下肢的生物动力运动,并可用来计算人体下肢在冲击外载荷或肌肉活性力的作用下,下肢的重要承力部位－膝关节处的结构力（包括：膝关节的咬合接触力、膝关节处四个主要韧带张力等）和人体下肢的肌肉群力;同时本模型也可用来计算人体下肢在运动期间,膝关节处的咬合位移以及膝关节和髋关节的屈伸位移等。另外,模型还为研究人工关节、人工韧带和人工肌肉     

Numerical Study of Heat Transfer in a Rectangular Channel with Porous Covering Obstacles

A numerical study is performed to analyze steady laminar forced convection in a channel in which discrete heat sources covered with porous material are placed on the bottom wall. Hydrodynamic and heat transfer results are reported. The flow in the porous medium is modeled using the Darcy–Brinkman–Forchheimer model. A computer program based on control volume method with appropriate averaging for diffusion coefficient is developed to solve the coupling between solid, fluid, and porous region. The effects of parameters such as Reynolds number, Prandtl number, inertia coefficient, and thermal conductivity ratio are considered. The results reveal that the porous cover with high thermal conductivity enhances the heat transfer from the solid blocks significantly and decreases the maximum temperature on the heated solid blocks. The mean Nusselt number increases with increase of Reynolds number and Prandtl number, and decrease of inertia coefficient. The pressure drop along the channel increases rapidly with the increase of Reynolds number.     

Transient response of a moving spherical shell in an acoustic medium

A ring-stiffened spherical shell is submerged in an acoustic medium. The shell is thin and elastic. The acoustic medium is inviscid, irrotational and compressible. The center of mass of the shell is subjected to a translational acceleration which is an arbitrary function of time. The absolute displacements of the shell are expressed in terms of the relative displacements and the displacement of the base of the shell, base being defined as the rigid ring placed at the equator. The motion of the acoustic medium is governed by the wave equation. The transient response of the shell is investigated numerically. The results are compared with the results of the in-vacuo response. The effects of the plane wave approximation and the base velocity on the transient response of the shell are studied. The numerical results show that the plane wave approximation accurately predicts the response of the shell in the acoustic medium for short times after excitation. The displacements of the shell in fluid are larger than those in vacuo. But when the base of the shell is restrained from translating, the displacements in fluid are smaller than those in vacuo. Therefore, base translation has a very significant effect on the transient response of the shells submerged in an acoustic medium.