RESUMEN

Hydrophobic metal-organic frameworks (MOFs) not only have high water stability, but also exhibit high adsorption capacity towards organic molecules, in particular hydrocarbons. Herein we report a rare metal fluoride organic framework MFOF-1 with high hydrophobicity, which is constructed from unprecedented fluoride- and sulfate-bridged cubane-type tetranuclear cobalt clusters. MFOF-1 consists of three types of polyhedral cages with face-sharing configurations, and possesses a novel (3,9)-connected 3D+3D→3D self-interpenetrating array or the rare pyr topology. MFOF-1 shows high thermal stability and high stability in water and even acid/base aqueous solutions, and exhibits rather high H2 and CO2 storage capacities at ambient pressure. Remarkably, MFOF-1 shows little adsorption of water but considerably high uptakes of methanol, n-hexane, cyclohexane, and benzene, and exhibits a certain degree of adsorption selectivity of benzene over cyclohexane.

RESUMEN

OBJECTIVE: In major liver resection, bacterial translocation appears to be an important mechanism in the pathogenesis of spontaneous infection. This study was designed to investigate the effects of splenic artery ligation on bacterial translocation after major liver resection. MATERIALS AND METHODS: Rats were divided into three groups: the sham operation group (SO group), the two-thirds partial hepatectomy group (PHx group) and the two-thirds partial hepatectomy plus splenic artery ligation group (PHx+Sp group). Bacterial translocation, endotoxemia, d-lactic acid and intestinal histology were analyzed among three groups. RESULTS: The rate of bacterial translocation was higher in the PHx rats than in the SO rats (65.0% vs. 6.67%; P=0.001), so that in the PHx+Sp rats (25.0%; P=0.011). Endotoxemia was not evident in the SO rats (0pg/ml) and blood endotoxin levels decreased in the PHx+Sp rats (1.47pg/ml) compared with the PHx rats (4.05pg/ml, P<0.001). d-lactic acid was also higher in both the PHx and PHx+Sp rats compared with the SO rats (39.09mg/ml, 23.36mg/ml, and 1.68mg/ml; P<0.01). CONCLUSION: Splenic artery ligation enhanced intestinal barrier function and diminished blood endotoxin levels and bacterial translocation in rats with major liver resection.

Asunto(s)

Traslocación Bacteriana/fisiología , Endotoxinas/sangre , Tracto Gastrointestinal/metabolismo , Hepatectomía/métodos , Íleon/patología , Ganglios Linfáticos/microbiología , Arteria Esplénica/cirugía , Animales , Infecciones Bacterianas/prevención & control , Femenino , Tracto Gastrointestinal/microbiología , Íleon/ultraestructura , Ácido Láctico/metabolismo , Ligadura , Permeabilidad , Presión Portal , Ratas , Ratas Sprague-Dawley

RESUMEN

Lithium cobalt oxide was synthesized by sol-gel with citric acid. The crystallization process of LiCoO2 gel precursor was studied by TG-DSC, and then it was calcined from 400 to 800 degrees C. The crystal structures of LiCoO2 powders formed at different temperatures were analyzed through X-ray diffraction, Infrared spectrum, Raman spectrum and transmission electron microscope. The results show that the mean grain sizes of LiCoO2 powders are about 20-40 nm, and increase with calcinating temperature changing from 400 to 700 degrees C, while decrease at 800 degrees C. The structure changed from modified spinel to layered-rock-salt with the calcinating temperature from 400 to 800 degrees C. In the modified spinel structure, Co2+ ions reside at the tetrahedral sites and Co3+ ions reside at the octahedral sites. However, in the layered-rock-salt structure, just only Co3+ ions reside at the octahedral sites.

RESUMEN

Nickel tetrasulfo-phthalocyanine (NiTSPc) was successfully doped into vinyltriethoxysilane (VTES)modified silicate gel glass by sol-gel technique, IR and UV-Vis spectral examination was carried out. The results show that vinyl has been introduced into SiO2 network, and the structure of gel glass is therefore changed. The encapsulation of NiTSPc does not make any noteworthy changes in the composition and structure of gel glass matrix. NiTSPc molecules are well dispersed in the organic modified matrix, and the phenomenon of aggregation is greatly suppressed.

RESUMEN

Carbon nanotubes (CNTs) were successfully introduced into silica gel glass matrix by physically doped sol-gel technique. The characterization of structure and spectra of the CNTs doped composites were carried out by X-ray diffraction, transmission electronic microscope, UV-Vis spectra, IR spectra and Raman spectra. The results show that CNTs are homogeneously dispersed in the silica gel glass matrix and the sol-gel processing does not appear to affect the intrinsic structure of CNTs. The introduction of CNTs doesn't make any noteworthy changes in the UV-Vis and IR spectra of silica gel glass matrix.

RESUMEN

We report here the preparation of nickel tetrasulfo-phthalocyanine (NiTSPc)-doped silica xerogel matrix obtained by sol-gel technique. The evolution of silica matrix's texture and the rate during the sol-gel process, as well as silica xerogel's pore structure were studied. Dimerization behavior of NiTSPc molecules was characterized by electronic absorption spectra, and changes in the absorption spectra were correlated with various stages of the sol-gel process. The results show that in the composites NiTSPc concurs in the forms of monomer and dimer, and dimerization is stronger during the latter stages. The reason is given from the change in the micro-environment in which NiTSPc existed during the sol-gel process.