Quorum Sensing Inhibition and Anti-Biofilm Activity of Traditional Chinese Medicines

Bacterial biofilm, a special stage which a large amount of bacteria are adhere to surface, increase resistance to antimicrobial agents. However, all the bacteria are possibly developed into biofilm, and bacterial biofilm is more difficult to remove from environment comparing to planktonic bacteria, which can be a strike to food industry. Many researchers have showed that traditional Chinese medicines contribute to the reduction of bacterial formation, since the important factor (quorum sensing) in biofilm formation is inhibited by traditional Chinese medicines. In this review, the effect of traditional Chinese medicines and its inhibition mechanism of biofilm formation on common bacterium biofilm are summarized, which provide a new direction for the removal of bacterial biofilm

Phylogeography of the Rice Frog, Fejervarya multistriata (Anura: Ranidae), from China Based on mtDNA D-loop Sequences

The rice frog, Fejervarya multistriata, is an amphibian widely distributed in China. In this study, we sampled the species across Its distributional area In China and sequenced the mtDNA D-loop to Investigate the genetic diversity and geographical pattern of the frog population. The results revealed 38 haplotypes in the population, with K2P values varying from 0.19% to 4.22%. Both a phylogenetic analysis and a nested clade analysis (NCA) detected two geographically isolated lineages respectively distributed around the Yangtze drainage (Yangtze lineage) and the south of China (southern lineage). NCA inferred a contiguous range expansion within the Yangtze lineage and allopatric fragmentation within the southern lineage, which might be partly due to the limited samples from this lineage. Accordingly, Fu's F-s test also Indicated a population expansion after glacial movement, Therefore, we assumed that the species history responding to glacial events shaped the present population pattern of F. multistriata on the Chinese mainland.National Natural Science Foundation of China [30570208]; Doctoral Program of Higher Education [20070384041

Pyrolysis of Sedum plumbizincicola, a zinc and cadmium hyperaccumulator: pyrolysis kinetics, heavy metal behaviour and bio-oil production

Appropriate disposal of hyperaccumulator biomass is a problem inhibiting the widespread use of phytoremediation technology. In the present study, kinetic analysis of the pyrolysis process of Sedum plumbizincicola, the behaviour of heavy metals and bio-oil composition were studied. The kinetic analysis of the pyrolysis process shows that activation energy (E) changed from 150 to 186 kJ mol(-1) and the frequency factor (A) changed from 1.34 x 10(11) to 8.99 x 10(15) s(-1). At temperatures of 450-750 A degrees C more than 66.3 % of zinc (Zn) remained in the char. More than 87.6 % of the cadmium (Cd) was found in the bio-oil. Pyrolysis at 650 A degrees C led to the highest yield of alkanes with low-oxygen compounds found in the bio-oil. Pyrolysis at 650 A degrees C can likely offer a valuable processing method for S. plumbizincicola and recovery of Zn from the char and recovery of Cd from the bio-oil will be attempted in future research

ALD-seeded hydrothermally-grown Ag/ZnO nanorod PTFE membrane as efficient indoor air filter

It has been well recognized that there are a number of indoor contaminants including particulate matter, gaseous pollutants and microbials. The removal of indoor contaminants often requires multiple layers of various air filters. Herein, we report on a multifunctional air purifying filter produced by the hydrothermal growth of ZnO nanorod-wrapped PTFE nanofibers, constructed of nanostructured Ag deposited on the ZnO nanorods with a hierarchical structure for gas contaminant removal. Atomic layer deposition (ALD) was used to seed a layer of ZnO nanoseeds onto the PTFE fibrils which were then subjected to a hydrothermal reaction to form ZnO nanorods. Ag nanoparticels were subsequently assembled on the surface of the ZnO nanorods via a silver electroless deposition reaction. The resulting composite membrane exhibited an excellent dynamic antibacterial property of similar to 100% and a formaldehyde degradation rate of 60%. Compared with the pristine membrane, the gas permeation of the composite membrane increased from 227.26 m(3) m(-2) h(-1) kPa(-1) to 275.36 m(3) m(-2) h-1 kpa(-1). The successful fabrication of this composite membrane with remarkable antibacterial and excellent formaldehyde degradation performance may provide a new route for the preparation of indoor air purification filters

Effects of annealing on the physico-chemical structure and permeation performance of novel hybrid membranes of poly(vinyl alcohol)/gamma-aminopropyl-triethoxysilane

Novel organic-inorganic hybrid membranes of poly(vinyl alcohol) (PVA)/gamma-aminopropyl-triethoxysilane (APTEOS) were prepared through a sol-gel approach in this study. The PVA/APTEOS hybrid membranes were characterized by a wide angle X-ray diffractometer (WXRD), scanning electronic microscope (SEM), themogravimetric analysis (TGA) and a contact angle meter to elucidate the effect of annealing temperature and time on the structure of the hybrid membranes. The swelling of the annealed hybrid membranes in an aqueous ethanol solution was investigated, and permeation performance of the annealed hybrid membranes was studied by pervaporation (PV) of 85 wt% ethanol aqueous solution. With annealing temperature or time increasing, both the swelling degree and the permeation flux of the hybrid membranes decreased, while water permselectivity increased. The interaction parameter of water with the membrane chi(13), and ethanol with the membrane chi(23) increased with annealing temperature and time increasing. The relation of the free volume with the permeation properties of the annealed hybrid membranes was studied by positron annihilation lifetime spectroscopy (PALS). And the diffusion behavior of water and ethanol in an aqueous ethanol solution through the hybrid membranes was analyzed by Maxwell-Stefan equation. (C) 2007 Elsevier Inc. All rights reserved

Fabrication and characterization of oriented carbon atom wires assembled on gold

Carbon atom wires (CAWs) are of the sp-hybridized allotrope of carbon. To augment the extraordinary features based on sp-hybridization, we developed an approach to make CAWs be self-assembled and orderly organized on Au substrate. The self-assembling process was investigated in situ by using scanning tunneling microscopy (STM) and electrochemical quartz crystal microbalance (EQCM). The properties of the assembled film were characterized by voltammetry, Raman spectroscopy, electron energy loss spectroscopy ( EELS), and the contact angle measurements. Experimental results indicated that the assembled CAW film was of the good structural integrity and well organized, with the sp-hybridized features enhanced. (C) 2008 Elsevier B. V. All rights reserved.National Natural Science Foundation of China [20473039]; State Key Laboratory of Physical Chemistry of Solid Surfaces (Xiamen University, China) [200405]; U. S. Department of Energy, Office of Basic Energy Science [DE-AC02-98CH10886