Flow Injection Analysis of Histidine with Enhanced Electrogenerated Chemiluminescence of Luminol

Histidine is one of the necessary basic amino acids in biological bases, which often controls the catalytic activity of enzymes and acts in holding the higher structure of proteins. Furthermore, it is also an important ingredient in pharmaceutical preparations used for treatment of hetpatosis and nephropathy. Therefore, the determination of histidine in biological fluids and pharmaceutical preparations is of great importance. Various methods have been proposed for the detection of histidine …     

The Electron Transfer Reaction between ρ-Nitrobenzoates and β-N, N-Dimethylaminonaphthalene

Photoinduced electron-transfer (PET) reactions are fundamentally important in biology and technology1,2. Because of the complexity of PET in biological systems, many simple compounds were synthesized to look into its detailed mechanism3. In previous papers, we reported the electron transfer reaction in the supramolecular systems assembled by mono-6-p-nitrobenzoyl-b-cyclodextrin 6 and naphthalene derivatives in aqueous solution4. In the present paper the intermolecular electron transfer from …     

New Thiophene Derivatives with Two-photon Excited Fluorescence

Organic molecules that can simultaneously absorb two or more photons in reaching theirexcited states have recently been the subject in various photon-electronic fields. Tomeet the criteria for various nonlinear optical applications, such as three-dimensionaloptical storage1 and up-converted lasing2, molecules with large two-photon absorption(TPA) cross-section σ are required and have been synthesized. These dyes generallybelong to the structural modes of D-π-D, A-π-A3 or D-π-A, where D…     

Exponential Synchronization of the Linearly Coupled Dynamical Networks with Delays

In this paper,the authors investigate the synchronization of an array of linearly coupled identical dynamical systems with a delayed coupling.Here the coupling matrix can be asymmetric and reducible.Some criteria ensuring delay-independent and delay- dependent global synchronization are derived respectively.It is shown that if the coupling delay is less than a positive threshold,then the coupled network will be synchronized.On the other hand,with the increase of coupling delay,the synchronization stability of the network will be restrained,even eventually de-synchronized.     

The Existence and Long-Time Behavior of Weak Solution to Bipolar Quantum Drift-Diffusion Model

The authors study the existence and long-time behavior of weak solutions to the bipolar transient quantum drift-diffusion model,a fourth order parabolic system.Using semi-discretization in time and entropy estimate,the authors get the global existence of nonnegative weak solutions to the one-dimensional model with nonnegative initial and homogenous Neumann(or periodic)boundary conditions.Furthermore,by a logarithmic Sobolev inequality,it is proved that the periodic weak solution exponentially approaches its mean value as time increases to infinity.     

Interaction of Chelerythrine Choloride in Acid Buffer with Calf-thymus DNA

Several benzo[c]phenanthridine alkaloids (BPA) were found in plants of Caprifoliaceae, Fumariaceae, Meliaceae, Papaveraceae, and Ruracea families1. BPA represent a group of natural products, exhibiting multiple pharmacological properties and biological ac…     

Refolding with Simultaneous Purification of Recombinant Human Granulocyte Colony-stimulating Factor from Escherichia coli Using Strong Anion Exchange Chromatography

Human granulocyte colony-stimulating factor (hG-CSF), a single chain polypeptidecontaining 174 amino acid residues (MW=18,800, pI=6.1), is one of the hemopoieticgrowth factors which plays an important role in stimulating proliferation, differentiation,and functional activation of bloodcells1. It contains a free cysteine at position 17 andtwo intramolecular disulfide bonds, Cys36-Cys42 and Cys64-Cys74, and the two disulfidebonds in G-CSF molecule are both required for its bioactivity2. Wh…     

Gnetuhainin P, a New Isorhapontigenin Dimer from the Lianas of Gnetum hainanense

Continuous investigation on oligostilbenes from the lianas of Gnetum hainanense resulted in the isolation of a new rhapontigenin dimer, Gnetuhainin P (1), in addition to the dimers of resveratrol and oxyresveratrol reported previously1. Gnetuhainin P (1) was obtained as a yellowish amorphous powder, [(]25D +6.6 (c 0.092, MeOH). The high resolution FABMS m/z 533.1866 [M+H]+ gave a molecular formula of C30H28O9 (C30H29O9 requires 533.1812), which corresponds to a isorhapontigenin dimer. …     

Characterization of Formation Kinetics of Self-Assembled Thiol Monolayers on Gold by Electrochemical Impedance Spectroscopy

Interest in the properties of organized monolayers has grown enormously in recent years because these monolayers can provide a means to control the interface at a molecular level1. The self-assemblies of alkanethiols and their derivatives were probably the most intensively studied due to their stability, well-packed structure, ease in preparation, and flexibility in designing the tail group2. The adsorption kinetics of thiol monolayer has been studied by using several techniques, including con…     

SYNTHESIS OF A SERIES OF NOVEL ORGANIC COMPOUNDS WITH TWO-PHOTON ABSORPTION AND TWO-PHOTON PUMPED LASING

Two-photon absorption (TPA) occurs through the simultaneous absorption of two photons via virtual states in a medium. Materials with large TPA cross section are gaining increasing attention recently due to their potential applications in optical data storage, two-photon up-converted lasing, two-photon-laser scanning fluorescence microscopy, optical power limiting and photodynamic therapy1-3. Numerous organic compounds have been investigated both experimentally and theoretically in order to u…