[Collagen spatial distribution in rapid atrial pacing dogs with or without superior vena cava and aortic root fat pad].

OBJECTIVE: To observe the collagen spatial distribution, collagen volume fraction (CVF) and Cx40, Cx43mRNA expressions in rapid atrial pacing dogs post vagal denervation by removing fat pad located between the medial superior vena cava and aortic root (SVC-Ao fat pad). METHODS: Twenty-four dogs were randomly divided into unpaced sham operation group (S group, n = 8), Keeping SVC-Ao fat pad group (K group, n = 8) and Removing SVC-Ao fat pad group (R group, SVC-Ao fat pad was removed by surgical excision before pacing, n = 8). K and R groups were paced for six weeks. Six weeks later, all dogs were sacrificed, left atrium (LA), right atrium (RA), left atrial appendage (LAA), right atrial appendage (RAA) and atrial septum (AS) were collected and stained with HE or Masson Trichrome or frozen in liquid nitrogen for quantifying the expression of Cx40, Cx43 mRNA by Real-time quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR). RESULTS: Spatial distribution of collagen fibers as well as CVF between S and R group were similar (all P > 0.05). CVF was significantly higher in K group compared to R group, especially at LAA and AS locations (all P < 0.05). Cx40mRNA expression in K group was significantly decreased in LA, RA, and significantly increased in LAA, RAA and AS compared those in S group (all P < 0.05), significantly lower in LA and RA while significantly higher in LAA and RAA compared to R group (all P < 0.05). Cx43mRNA expression in K group was significantly reduced in LA, RA, LAA and RAA while significantly increased in AS compared to S group (all P < 0.05), significantly higher in LA, RA, RAA and AS while significantly lower in LAA compared to R group. CONCLUSION: Pacing induced collagen remodeling and modulation on Cx40mRNA and Cx43 mRNA expressions could be partially attenuated by removing SVC-Ao fat pad suggesting vagal denervation plays a key role in the initiation and preservation of atrial fibrillation.

Study on the nature of interaction of furan with various hydrides.

The nature of interactions of furan with various hydrides (Y) (Y=HF,HCl,H2O,H2S,NH3,PH3) is investigated using ab initio calculations. The contribution of attractive (electrostatic, inductive, and dispersive) and repulsive (exchange) components to the interactions energy is analyzed. HF, H2O, and NH3 favor sigma o-type H bonding, while HCl, H2S, and PH3 favor pi-type H bonding. Interaction energy decomposition reveals that sigma o-type complexes interactions are predominantly electrostatic in nature, while the dispersion and electrostatic interactions dominate the pi-type complexes.

[The luminescence characteristics of rare earth complex Tb0.5 Eu.5 (TTA)3Dipy].

The new complex Tb0.5 Eu0.5 (TTA)3Dipy was synthesized. By doping polymer PVK with Tb0.5 Eu0.5 (TTA)3Dipy, the EL device was fabricated with the structure of ITO/PVK: Tb0.5 Eu0.5 (TTA)3Dipy/PBD/Al using PVK: Tb0.5 Eu0.5 (TTA)3Dipy as the emitting layer. Compared with the blend PVK: Eu(TTA)3, the Tb3+ acts as an energy transfer bridge, which enhances the energy transfer efficiency between PVK and Tb0.5 Eu0.5 (TTA)3Dipy. As a result, the emission of Eu3+ is enhanced with the quenching of the emission of PVK. The process of energy transfer was studied.

Theoretical study on intermolecular interactions between furan and dihalogen molecules XY(X,Y=F,Cl,Br).

Equilibrium geometries, interaction energies, atomic charge, and charge transfer for the intermolecular interactions between furan and dihalogen molecules XY(X; Y=F,Cl,Br) were studied at the MP2aug-cc-pVDZ level. Three types of geometry are observed in these interactions: the pi-type geometry (I), in which the XY lies above the furan ring and almost perpendicularly to the C4-C5 bond of furan; the sigma-type geometry (II), where the X atom is pointed toward the nonbonding electron pair (n pair) of oxygen atom in furan; and the chi-type geometry (III), describing a blueshift hydrogen bond formed between the hydrogen atom of furan and dihalogen molecules XY. The calculated interaction energies show that the pi-type structures are more stable than the corresponding sigma-type and chi-type structures. To study the nature of the intermolecular interactions, an energy decomposition analysis was carried out and the results indicate that both the pi-type and sigma-type interactions are dominantly inductive energy in nature, while dispersion energy governs the chi-type interactions.

A novel cetyltrimethyl ammonium silver bromide complex and silver bromide nanoparticles obtained by the surfactant counterion.

A novel cetyltrimethyl ammonium silver bromide (CTASB) complex has been prepared simply through the reaction of silver nitrate with cetyltrimethyl ammonium bromide (CTAB) in aqueous solution at room temperature by controlling the concentration of CTAB and the molar ratio of CTAB to silver nitrate in the reaction solution, in which halogen in CTAB is used as surfactant counterion. The structure and thermal behavior of cetyltrimethyl ammonium silver bromide have been investigated by using X-ray diffraction (XRD), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), UV/vis spectroscopy, thermal analysis (TG-DTA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results show that the complex possesses a metastable layered structure. Upon heating the CTASB aqueous dispersion to above 80 degrees C, the structure change of the complex took place and CTAB-capped nanosized silver bromide particles further formed.

Preparation of TiO2-MoO3 nano-composite photo-catalyst by supercritical fluid dry method.

A series of TiO2-MoO3 nano-composite photocatalysts were prepared by supercritical fluid dry method (SCFD) and an impregnation technique with TiCl4 and (NH4)6Mo7O24.4H2O as the starting materials. The catalysts were characterized by the means of XRD, TEM and UV-Vis. Methyl orange was used as model compound for the evaluation of their catalytic activities. The results indicated that the photo-catalyst prepared by SCFD had the advantages of small size (12.84 nm), narrow distribution and good dispersivity. The presence of small amount of Mo in composite catalyst gives rise to the red shift of its absorbance wavelength, decrease of its energy gap and increase of the utility of visible light. Furthermore, higher surface acidity of the photo-catalyst was obtained as the result of the addition of MoO3. Compared with pure TiO2, the catalytic activity of the TiO2-MoO3 nano-composite photo-catalyst was improved significantly. As the doping concentration of the composite catalysts was controlled at 0.6% (molar percentage), 100% degradation of methyl orange was achieved with in 1.2 h irradiation time.

[Ion floatation-spectrophotometric determination of palladium(II) content in acetaldehyde catalyst].

The nature of palladium (I) and copper (II) is very similar, so it is very difficult to determine trace palladium (II) in the coexistence of a great quantity of copper (II). This paper applied ion floatation-spectrophotometric principle, using 1-(2-pyridylazo)-2-naphthol (PAN) as collector, and through controlling pH of the solution and determination wavelength, without separation to determine palladium (II) content in acetaldehyde catalyst with a great quantity of copper (II). The relative error was 0.61%, and RSD was 2.33%. The results were satisfactory.