ENVIRONMENTAL BIOTECHNOLOGY Increased bioclogging and corrosion risk by sulfate addition during iodine recovery at a natural gas production plant

Abstract Iodine recovery at a natural gas production plant in Japan involved the addition of sulfuric acid for pH adjustment, resulting in an additional about 200 mg/L of sulfate in the waste brine after iodine recovery. Bioclogging occurred at the waste brine injection well, causing a decrease in well injectivity. To examine the factors that contribute to bioclogging, an on-site experiment was conducted by amending 10 L of brine with different conditions and then incubating the brine for 5 months under open air. The control case was exposed to open air but did not receive additional chemicals. When sulfate addition was coupled with low iodine, there was a drastic increase in the total amount of accumulated biomass (and subsequently the risk of bioclogging) that was nearly six times higher than the control. The bioclogging-associated corrosion rate of carbon steel was 84.5 μm/year, which is four times higher than that observed under other conditions. Analysis of the microbial communities by denaturing gradient gel electrophoresis revealed that the additional sulfate established a sulfur cycle and induced the growth of phototrophic bacteria, including cyanobacteria and purple bacteria. In the presence of sulfate and low iodine levels, cyanobacteria and purple bacteria bloomed, and the accumulation of abundant biomass may have created a more conducive environment for anaerobic sulfate-reducing bacteria. It is believed that the higher corrosion rate was caused by a differential aeration cell that was established by the heterogeneous distribution of the biomass that covered the surface of the test coupons

Functions of human olfactory mucus and age-dependent changes

Abstract Odorants are detected by olfactory sensory neurons, which are covered by olfactory mucus. Despite the existence of studies on olfactory mucus, its constituents, functions, and interindividual variability remain poorly understood. Here, we describe a human study that combined the collection of olfactory mucus and olfactory psychophysical tests. Our analyses revealed that olfactory mucus contains high concentrations of solutes, such as total proteins, inorganic elements, and molecules for xenobiotic metabolism. The high concentrations result in a capacity to capture or metabolize a specific repertoire of odorants. We provide evidence that odorant metabolism modifies our sense of smell. Finally, the amount of olfactory mucus decreases in an age-dependent manner. A follow-up experiment recapitulated the importance of the amount of mucus in the sensitive detection of odorants by their receptors. These findings provide a comprehensive picture of the molecular processes in olfactory mucus and propose a potential cause of olfactory decline

Identification of waves in the lower-hybrid frequency range in the scrape-off layer plasma of Alcator C-Mod

Polarization resolved measurements of the parallel refractive index Nk ≡ ckk/ω of the driven RF waves in the lower hybrid (LH) range of frequencies are performed using arrays of RF magnetic probes in the scrape-off layer plasma of Alcator C-Mod. The measured Nk of the RF magnetic field component parallel to the background magnetic field is about -1.6, which corresponds to the peak of the launched LH Nk spectrum. Based on the wave dispersion relationship, this wave is identified as the LH slow wave. On the other hand, the RF magnetic field component perpendicular to the magnetic field is found to have a lower Nk of -1.2, and is detected only near the last closed flux surface. This wave is identified as the LH fast wave generated by slow-fast wave mode conversion