In the development of noble gas MRI in humans, the traditional single-tuned transmit coil does not suitable for imaging acquisitions. This paper presents a novel radio frequency(RF) coil design method for applications of 1H/3He MRI system at the ultra-low field of 0.06mT.For the complex model of the dual- tuned 1H/3He coil, the traditional Electromagnetic(EM) simulation is not applicable due to its long computing time, the EM field and radio frequency (RF) circuit co-simulation method thus is implemented to accelerate the analysis, which results in an effective evaluation. The simulation results show that the proposed model has the potential for imaging of lung with 1H/3He MRI system at the ultra-low field.

Flavobacterium columnare, the causative agent of columnaris disease, infects freshwater fish worldwide. However, the pathogenicity of this bacterium is poorly understood due possibly to the lack of an efficient in-frame knockout technique. In order to improve electroporation efficiency, the type I restriction-modification system (R-M system) was cloned and its role in electroporation was examined in F. columnare G4 strain. The complete sequence of type I R-M system in the bacterium, designated as Fcl, contains all three subunits of type I R-M system, named as fclM, fclS, fclR, respectively, with the identification of a hypothetical gene, fclX. Constitutive transcription of the three genes was observed in F. columnare G4 by RT-PCR. The ORF of fclM and fclS was cloned into the plasmid pACYC184 and transformed into Escherichia coli TOP10. The resultant E. coli strain, designated as E. coli TOPmt, was transformed with the integrative plasmid pGL006 constructed for F. columnare G4. The integrative plasmid was re-isolated from TOPmt and incubated with the lysate of F. columnare G4. The re-isolated integrative plasmid, designated as pGL006′, showed higher resistance than pGL006. With pGL006′, the electroporation efficiency of the strain G4 increased 2.6 times, while that of F. columnare G18 was not obviously improved. Furthermore, a method to improve the electroporation efficiency of F. columnare G4 was developed using the integrative plasmid methylated by E. coli TOPmt which contains the fclM and fclS gene of F. columnare G4. Further analyses showed that the fcl gene cluster may be a unique type I R-M system in F. columnare G4. It will be of significant interest to examine the composition and diversity of R-M systems in strains of F. columnare in order to set up a suitable genetic manipulation system for the bacterium.

British Journal of Pharmacology (2008) 154, 1161; doi:10.1038/bjp.2008.251

A new type of nickel-platinum-carbon catalyst was used in the microdetermination of oxygen in organic compounds with satisfactory results. The results of determination and the properties of the catalyst are also discussed.