3,057 research outputs found
Salmonella typhimurium harboring plasmid expressing interleukin-12 induced attenuation of infection and protective immune responses
IL-12 is known to be an essential cytokine which appears to provide protective immunity against intracellular bacteria, such as Salmonella. In this study, we investigated the possibility of developing a vaccine using IL-12 against virulent Salmonella. We used the host defense system activated by cytokine IL-12. The highly virulent Salmonella strain (Salmonella typhimurium UK-1) was transformed with cytokine-expressing plasmids. These live, wild-type pathogens were used as vaccine strains without undergoing any other biological or genetic attenuating processes. The newly developed strains induced partial protection from infections (30-40%). Of note, the interleukin-12 transformed pathogen was safe upon immunization with low doses (103 CFU), induced IgG responses, and stimulated protective immune responses against Salmonella Typhimurium in mice (80-100%). These results suggest that IL-12 induced attenuation of wild-type Salmonella in the host infection stage and vaccine development using the wild-type strain harboring IL-12 secreting plasmids may be considered as an alternative process for intracellular bacterial vaccine development without the inconvenience of time-consuming attenuation processes
Solid-Cryogen Cooling Technique for Superconducting Magnets of NMR and MRI
This paper describes a solid-cryogen cooling technique currently being developed at the M.I.T. Francis Bitter Magnet Laboratory for application to superconducting magnets of NMR and MRI. The technique is particularly appropriate for “dry” magnets that do not rely on liquid cryogen, e.g., liquid helium (LHe), as their primary cooling sources. In addition, the advantages of a cryocirculator (a combination of a cryocooler and a working fluid circulator) over a cryocooler as the primary cooling source for dry magnets are described. The four magnets described here, all incorporating this cooling technique described and currently being developed at the FBML, are: 1) a solid-nitrogen (SN[subscript 2])-cooled Nb[subscript 3]Sn 500-MHz/200-mm MRI magnet with an operating temperature range between 4.2 K (nominal) and 6.0 K (maximum with its primary cooling source off); 2) an SN[subscript 2]-cooled MgB[subscript 2] 0.5-T/800-mm MRI magnet, 1015 K; 3) an SN[subscript 2]-cooled compact YBCO “annulus” 100-MHz/9-mm NMR magnet, 10-15 K; 4) an SN2-cooled 1.5T/75-mm NbTi magnet for slow magic-angle-spinning NMR/MRI, 4.5-5.5 K
Accounting Conservatism, Changes In Real Investment, And Analysts Earnings Forecasts
This study examines whether sell-side analysts fully incorporate into their earnings forecasts the joint effects between accounting conservatism and changes in real investment on the quality of current earnings. Our results indicate that sell-side analysts do not fully incorporate such effects when they forecast future earnings so that they overestimate (underestimate) future earnings when current earnings are inflated (depressed) by those effects. Thus, we conclude that sell-side analysts do not recognize fully the joint effects between accounting conservatism and real activity on the earnings quality and that they need to mitigate their bias to enhance market efficiency by providing investors with a good benchmark for their earnings expectation
Generation of subspecies level-specific microbial diagnostic microarrays using genes amplified from subtractive suppression hybridization as microarray probes
The generation of microarray probes with specificity below the species level is an ongoing challenge, not least because the high-throughput detection of microorganisms would be an efficient means of identifying environmentally relevant microbes. Here, we describe how suppression subtractive hybridization (SSH) can be applied to the production of microarray probes that are useful for microbial differentiation at the subspecies level. SSH was used to initially isolate unique genomic sequences of nine Salmonella strains, and these were validated in quadruplicate by microarray analysis. The results obtained indicate that a large group of genes subtracted by SSH could serve together, as one probe, for detecting a microbial subspecies. Similarly, the whole microbial genome (not subjected to SSH) can be used as a species-specific probe. The detailed methods described herein could be used and adapted for the estimation of any cultivable bacteria from different environments
THE HOT GAS DESULFURIZATION IN A COMPACT TWO BEDS SYSTEM INTEGRATED WITH COAL GASIFICATION AND FISHER-TROPSCH SYSTEM
The hot gas desulfurization (HGD) technique is one of the elemental technologies of syngas purification having both thermal efficiency and very low emissions. The HGD is a novel method to efficiently remove H2S and COS in the syngas with regenerable sorbents at high temperature and high pressure condition. We propose a compact hot gas desulfurization system by which its operability is improved in stabilizing pressure balances among units. The proposed compact two beds system has two bubbling beds, solid injection nozzle, solid conveying line, and riser. The compact desulfurization system was located between coal gasifier and Fisher-Tropsch (F-T) reactor to desulfurize syngas in order not to deactivate F-T catalyst. To check feasibility of the compact desulfurization system at high pressure condition, both cold mode and hot mode tests have been performed. In the integrated system, the compact desulfurization system has removed H2S and COS in the syngas and supplied the cleaned syngas to the F-T reactor during the continuous operation at high pressure condition
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