QSAR study of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl) pyrimidine-5-carboxylate: an inhibitor of AP-1 and NF-kappa B mediated gene expression based on support vector machines

The support vector machine, as a novel type of learning machine, for the first time, was used to develop a QSAR model of 57 analogues of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl)pyrimidine-5-carboxylate (EPC), an inhibitor of AP-1 and NF-kappa B mediated gene expression, based on calculated quantum chemical parameters. The quantum chemical parameters involved in the model are Kier and Hall index (order3) (KHI3), Information content (order 0) (IC0), YZ Shadow (YZS) and Max partial charge for an N atom (MaxPCN), Min partial charge for an N atom (MinPCN). The mean relative error of the training set, the validation set, and the testing set is 1.35%, 1.52%, and 2.23%, respectively, and the maximum relative error is less than 5.00%.     

Monitoring molecular beacon DNA probe hybridization at the single-molecule level

We have monitored the reaction dynamics of the DNA hybridization process on a liquid/solid interface at the single-molecule level by using a hairpin-type molecular beacon DNA probe. Fluorescence images of single DNA probes were recorded by using total internal reflection fluorescence microscopy. The fluorescence signal of single DNA probes during the hybridization to individual complementary DNA probes was monitored over time. Among 400 molecular beacon DNA probes that we tracked, 349 molecular beacons (87.5 %) were hybridized quickly and showed an abrupt fluorescence increase, while 51 probes (12.5 %) reacted slowly, resulting in a gradual fluorescence increase. This ratio stayed about the same when varying the concentrations of cDNA in MB hybridization on the liquid/surface interface. Statistical data of the 51 single-molecule hybridization images showed that there was a multistep hybridization process. Our results also showed that photostability for the dye molecules associated with the double-stranded hybrids was better than that for those with the single-stranded molecular beacon DNA probes. Our results demonstrate the ability to obtain a better understanding of DNA hybridization processes using single-molecule techniques, which will improve biosensor and biochip development where surface-immobilized molecular beacon DNA probes provide unique advantages in signal transduction.     

Photoelectrochemical decomposition of water on nanocrystalline BiVO4 film electrodes under visible light

The nanocrystalline BiVO4 film electrode on conducting glass showed an excellent efficiency (IPCE = 29% at 420 nm) for the decomposition of water under visible light.     

One-pot synthesis of 2,5-diethynyl-3,4-dibutylthiophene substituted multitopic bipyridine ligands: redox and photophysical properties of their ruthenium(II) complexes

A facile and original synthesis of four 2,2'-bipyridine (bipy) ligands grafted with thiophene subunits is described using phase transfer experimental conditions: related Ru(II) complexes exhibit well-defined redox and photophysical properties which were probed by cyclic voltammetry, UV-vis, steady-state emission and transient absorption spectroscopy.     

Enzymatic profiling system in a small-molecule microarray

[reaction: see text] We have developed a microarray-based strategy for detection of three major classes of hydrolytic enzymes on the basis of their catalytic activities. This enables the sensitive detection of proteins not merely by their bindings but rather by their enzymatic activities. This may provide a valuable tool for screening, identification, and characterization of new enzymes in a high-throughput fashion.     

Simultaneous analysis of caffeic acid derivatives and alkamides in roots and extracts of Echinacea purpurea by high-performance liquid chromatography-photodiode array detection-electrospray mass spectrometry

High-performance liquid chromatography (HPLC) coupled with UV photodiode-array detection and electrospray ionization mass spectrometry was developed for the simultaneous analysis of caffeic acid derivatives and alkamides in the roots and extracts of Echinacea purpurea. Caffeic acid derivatives and alkamides produced very abundant peaks in the total ion current chromatogram during negative and positive cone voltage switching. Cichoric acid and the isomer pair, dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamide, were used as a standard for quantification of caffeic acid derivatives and alkamides in E. purpurea. This novel method surpasses previously published ones in product quality control and providing the HPLC chromatographic fingerprints of biological active components in E. purpurea.     

Hypnotic action of N3-substituted arabinofuranosyluracils on mice

Methyl (2), ethyl (3), propyl (4), butyl (5), allyl (6), benzyl (7), o-, m-, p-xylyl (8-10), and alpha-phenylethyl (11) derivatives of arabinofuranosyluracil (1) were synthesized and their pharmacological effects in mice were examined by using hypnotic activity and synergism with pentobarbital as indices for the CNS depressant effects. At a dose of 2.0 micromol/mouse by intracerebroventricular injection, the values of mean sleeping time induced by 7-11 were 144, 154, 117, 33, and 34 min, respectively, whereas the alkyl (2-6) derivatives did not cause any hypnotic activity. N3-o-Xylylarabinofuranosyluracil (8) displayed the most potent hypnotic activity among the derivatives tested. Certain derivatives (6-11) significantly prolonged the pentobarbital-induced sleeping time compared to control. The present study indicated that substitution with benzyl and/or related groups on the N3-position of arabinofuranosyluracil produced CNS depressant effects.     

Hydrogen bond directed formation of liquid-crystalline merocyanine dye assemblies

Combined interaction of triple hydrogen bonding, dipolar pi-pi aggregation and micro-segregation in a melamine-barbituric acid dye assembly leads to a columnar mesophase which could be characterized by optical polarising microscopy, differential scanning calorimetry and X-ray diffraction.     

(2+1)-Dimensional Fermion Determinant in a Constant Background Field at Finite Temperature and Density

We evaluate exactly both the nonrelativistic and relativistic fermion determinant in 2+1 dimensions in a constant background field at finite temperature. The effect of finite chemical potential is also considered. In both cases, the systems are decoupled into an infinite number of 1+1 fermions by Fourier transformation in the -variable. The total effective actions demonstrate nonextensiveness in the -dimension.