Spectrophotometric Determination of Carbonate Ion Concentrations: Elimination of Instrument-Dependent Offsets and Calculation of In Situ Saturation States
This work describes an improved algorithm for spectrophotometric determinations of seawater carbonate ion concentrations ([CO32–]spec) derived from observations of ultraviolet absorbance spectra in lead-enriched seawater. Quality-control assessments of [CO32–]spec data obtained on two NOAA research cruises (2012 and 2016) revealed a substantial intercruise difference in average Δ[CO32–] (the difference between a sample’s [CO32–]spec value and the corresponding [CO32–] value calculated from paired measurements of pH and dissolved inorganic carbon). Follow-up investigation determined that this discordance was due to the use of two different spectrophotometers, even though both had been properly calibrated. Here we present an essential methodological refinement to correct [CO32–]spec absorbance data for small but significant instrumental differences. After applying the correction (which, notably, is not necessary for pH determinations from sulfonephthalein dye absorbances) to the shipboard absorbance data, w...
Jonathan D. Sharp; Robert H. Byrne; Xuewu Liu; Richard A. Feely; Erin E. Cuyler; Rik Wanninkhof; Simone R. Alin
We recently generalized the formerly alignment-dependent multivariate image analysis applied to quantitative structure–activity relationships (MIA-QSAR) method through the application of the discrete Fourier transform (DFT), allowing for its application to noncongruent and structurally dive ... more
Poly-ADP-ribosylation (PARylation) is a protein posttranslational modification (PTM) that is critically involved in many biological processes that are linked to cell stress responses. It is catalyzed by a class of enzymes known as poly-ADP-ribose polymerases (PARPs). In particular, PARP1 is ... more
This review focuses on the type A cytochrome c oxidases (CcO), which are found in all mitochondria and also in several aerobic bacteria. CcO catalyzes the respiratory reduction of dioxygen (O2) to water by an intriguing mechanism, the details of which are fairly well understood today as a r ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more