The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast

The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al

A Novel Structural Assessment Technique to Prevent Damaged FRP-Wrapped Concrete Bridge Piers from Collapse

Repairing deteriorated concrete bridge piers using externally wrapped fiber reinforced polymer (FRP) composites have been proven as an effective approach. This technique has also been applied to low-rise building structures. Failures in FRP-wrapped concrete structures may occur by flexural failures of critical sections or by debonding of FRP plate from the concrete substrate. Debonding in the FRP/adhesive/concrete interface region may cause a significant decrease in member capacity leading to a premature failure of the system. In this chapter, a novel structural assessment technique aiming at inspecting the near-surface FRP debonding and concrete cracking of damaged FRP-wrapped concrete bridge piers to prevent the structures from collapse is presented. In the first part of this chapter, failure mechanisms of FRP-wrapped concrete systems are briefly discussed. The second part of this chapter introduces a novel structural assessment technique in which far-field airborne radar is applied. In this development, emphasis is placed on inspection of debonding in glass FRP (GFRP)-wrapped concrete cylinders, while the technique is also applicable to beams and slabs with bonded GFRP composites. Physical radar measurements on laboratory specimens with structural damages were conducted and used for validating the technique. Processed experimental measurements have shown promising results for the future application of the technique. Finally, research findings and issues are summarized.National Science Foundation (U.S.) (Grant CMS-0324607)Lincoln Laborator

Soft Ionization of Thermally Evaporated Hypergolic Ionic Liquid Aerosols

Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources

Using impulse radar for floor and wall assessment in concrete system buildings

Peer reviewed: NoNRC publication: Ye