APPLICATIONS OF THE P-R SCHEME FOR GENERALIZED NONLINEAR SCHRODINGER EQUATIONS IN SOLVING SOLITON SOLUTIONS

Spatial soliton solutions of a class of generalized nonlinear Schrodinger equations in N-space are discussed analytically and numerically. This achieved using a traveling wavemethod to formulate one-soliton solution and the P-R method is employed to the numerlcal solutions and the interactions between the solirons for the generalized nonlinear systems in Z-pace.The results presented show that the soliton phenomena are characteristics associated with the nonlinearhies of the dynamical systems.     

Synthesis, structure, electrochemistry, and electrochemiluminescence of thienyltriazoles

Four blue-emitting thienyltriazoles with desired N and O coordination atoms were prepared in high yield via click chemistry for potential incorporation into metal complexes. Three of their crystal structures were determined by X-ray crystallography. The electrochemical properties, electronic structures of these thienyltriazoles, 1-4, and their correlations were studied using cyclic voltammetry and differential pulse voltammetry techniques along with density function theory (DFT) calculations. All of the compounds underwent irreversible redox reactions, leading to unstable electrogenerated radical cations and anions. Electrochemical gaps determined from the differences between first formal reduction and oxidation reactions were correlated to HOMO-LUMO energy gaps obtained from UV-vis spectroscopy and the DFT calculations as well as energies of excited states measured from photoluminescence spectroscopy. We observed weak electrochemiluminescence (ECL) from annihilation of these thienyltriazole radicals in acetonitrile containing 0.1 M tetra-n-butylammonium perchlorate as electrolyte. An enhancement in ECL efficiency ranging from 0.16 to 0.50% was observed upon addition of benzoyl peroxide as a coreactant in the above electrolyte solutions. The generation of excimers in solutions of 1-4 was observed as seen by the red-shift in ECL maxima relative to their corresponding photoluminescence peak wavelengths. Our work is of importance for the development of efficient blue-emitting fluorophores via click chemistry that could be potential luminophores in metal complexes.     

Electrogenerated chemiluminescence of triazole-modified deoxycytidine analogues in N,N-dimethylformamide

Triazole-modified deoxycytidines have been prepared for incorporation into single-stranded deoxyribonucleic acid (ssDNA). Electrochemical responses and electrogenerated chemiluminescence (ECL) of these deoxycytidine (dC) analogues, 1-4, were investigated as the monomers. Cyclic voltammetry and differential pulse voltammetry techniques were used to determine the oxidation and reduction potentials of 1-4, along with the reversibility of their electrochemical reactions. The dC analogues, in N,N-dimethylformamide containing 0.1 M tetra-n-butylammonium perchlorate as electrolyte, exhibited weak relative ECL efficiencies following the annihilation mechanism, while these efficiencies were enhanced with the use of benzoyl peroxide following the coreactant mechanism. It was shown that these nucleosides could generate excited monomers, and excimers as seen by the red-shifted ECL maxima relative to their corresponding photoluminescence peak wavelengths.     

Improved convergence of binding affinities with free energy perturbation: Application to nonpeptide ligands with pp60src SH2 domain

Free Energy Perturbations (FEP) in the context of Monte Carlo (MC) simulations were conducted to predict the relative free energies of binding for a series of human Src SH2 domain ligands. Two procedures for disappearing atoms during a single-topology FEP are investigated and dramatic differences in free energy convergence behavior are seen. Comparison of these two protocols suggests that the coupling of the removal of angular constraints with the disappearance of an atom may significantly slow free energy convergence. The series of ligands under investigation here cover a range of modifications at the 3-position of 4-({[4-(cyclohexyl methoxy)benzyl]amino}carbonyl) phenyl phosphate. Unlike any other compound in this study, the 3-amide analog can form two hydrogen bonds within the region of the perturbation, one to a backbone amide hydrogen and one to a highly coordinated water molecule. Agreement with experimental trends in binding affinity is seen, although the computed relative free energy of binding of the amido compound is underestimated. These results are reconciled by examination of the hydration energies of model systems, which predict primary amides as too hydrophilic.     

Hydrogen bonding properties of oxygen and nitrogen acceptors in aromatic heterocycles

The directionality and relative strengths of hydrogen bonds to monocyclic aromatic heterocycles were investigated using crystal structure data and theoretical calculations. Surveys of the Cambridge Structural Database for hydrogen bonds between C^(sp3)(SINGLE BOND)O(SINGLE BOND)H and aromatic fragments containing one or more nitrogen and/or oxygen heteroatoms showed that hydrogen bonds to nitrogen atoms are much more abundant than to oxygen. Distinct preferred orientations were also revealed in these surveys. Theoretical calculations were performed on the interaction of methanol with pyridine, pyrimidine, pyrazine, pyridazine, oxazole, isoxazole, 1,2,4-oxadiazole, and furan as models for the heterocyclic fragments. The intermolecular potential surface was thoroughly scanned using a model potential that accurately described the electrostatic forces (derived from distributed multipole analysis) with empirical parameters for the repulsion and dispersion terms. Minima on this surface agreed well with the observed orientations in the data base and they were typically deeper for nitrogen than for oxygen acceptors, although the hydrogen bond strength and geometry was influenced by other heteroatoms in the ring. These results were confirmed by highly accurate intermolecular perturbation theory calculations, which also estimated the deviations from hydrogen bonding in the traditional nitrogen lone pair direction that could occur with negligible reduction in the interaction energy. © 1997 John Wiley & Sons, Inc. J Comput Chem 18 : 2060–2074, 1997     

生物细胞中的能量学和力学

世界上的生物总是在不停地运动着。动物在奔跑、飞翔、游泳。植物日复一日追逐着太阳。即使是微生物,也在不停地运动。我们体内的细胞的各个部分也在不停地运动,这些运动使我们的细胞可以生长、分裂、改变形状、甚至运动。 除了运动之外,我们的身体还必须能够感知到周围的世界。活体细胞可以对周围很多种机械刺激产生反馈,比如伸展,液体的流动,渗透压的改变,周围环境的硬度。我们的触觉和听觉要求细胞能够感知非常细微的机械力。我们对血压的调节能力依赖于分布在体内动脉和静脉的机械敏感性。     

Analysis of thrombin‐antithrombin complex formation using microchip electrophoresis and mass spectrometry

Preterm birth (PTB) related health problems take over one million lives each year, and currently, no clinical analysis is available to determine if a fetus is at risk for PTB. Here, we describe the preparation of a key PTB risk biomarker, thrombin‐antithrombin (TAT), and characterize it using dot blots, MS, and microchip electrophoresis (µCE). The pH for fluorescently labeling TAT was also optimized using spectrofluorometry and spectrophotometry. The LOD of TAT was measured in µCE. Lastly, TAT was combined with six other PTB risk biomarkers and separated in µCE. The ability to make and characterize TAT is an important step toward the development of an integrated microfluidic diagnostic for PTB risk.     

Microfluidic fabrication of novel polymeric core-shell microcapsules for storage of CO2 solvents and organic chelating agents

Monodispersed polymeric microcapsules loaded with CO₂ solvents or chelating agents were produced by capillary microfluidics by photopolymerisation of three different UV curable materials, 1,6-hexanediol diacrylate (HDDA), Norland Optical Adhesive (NOA) 81, and Semicosil® 949 UV A/B (PDMS). Polymerization of HDDA and NOA 81 started after exposure to UVA light for 5 s and was completed within a minute, as confirmed by continuous FT-IR. Corrosive aqueous solutions of tetraethylenepentamine and diisopropyl iminodiacetic acid were encapsulated with 100% efficiency into poly(HDDA) and cured NOA81 shells without any leakage during prolonged storage. Poly(HDDA) shells were mechanically more stable than cured NOA81 and PDMS shells and resistant to drying-induced shell buckling. NOA81 and PDMS capsules underwent morphological changes during freeze drying leading to the formation of dimpled and crescent-moon-shaped particles, respectively. The storage stability in a hypotonic solution and buckling resistance of PDMS shells were significantly improved by embedding carbon-based nanomaterials into PDMS matrix. The incorporation of 0.5 wt% multi-walled carbon nanotubes into PDMS matrix led to an increase in a Shore A hardness from 1.6 to 2.3. A uniform distribution of MWCNTs in the polymer network was confirmed by XRD. All fabricated shells were thermally stable up to the temperature of 300°C.     

Evaluation of a Bispidine-Based Chelator for Gallium-68 and of the Porphyrin Conjugate as PET/PDT Theranostic Agent

In this study a bispidine ligand has been applied to the complexation of gallium(III) and radiolabelled with gallium-68 for the first time. Despite its 5-coordinate nature, the resulting complex is stable in serum for over two hours, demonstrating a ligand system well matched to the imaging window of gallium-68 positron emission tomography (PET). To show the versatility of the bispidine ligand and its potential use in PET, the bifunctional chelator was conjugated to a porphyrin, producing a PET/PDT-theranostic, which showed the same level of stability to serum as the non-conjugated gallium-68 complex. The PET/PDT complex killed >90 % of HT-29 cells upon light irradiation at 50 μm . This study shows bispidines have the versatility to be used as a ligand system for gallium-68 in PET.