Possibilities for Misinterpretation in ASV-Speciation Studies of Natural Waters

Die Probleme, die bei Speciesuntersuchungen von Spurenelementen mit Hilfe der Differentialpuls Anodic Stripping Voltammetrie auftreten, werden zu-sammenfassend dargestellt. Neben den bei der eigentlichen Bestimmung auftretenden Problemen, werden auch solche erwähnt, die mit der Probennahme sowie der Lagerung und Vorbehandlung der Proben in Zusammenhang stehen

Electrochemical methods for speciation of trace elements in marine waters. Dynamic aspects

The contribution of electrochemical methods to the knowledge of dynamic speciation of toxic trace elements in marine waters is critically reviewed. Due to the importance of dynamic considerations in the interpretation of the electrochemical signal, the principles and recent developments of kinetic features in the interconversion of metal complex species will be presented. As dynamic electrochemical methods, only stripping techniques (anodic stripping voltammetry and stripping chronopotentiometry) will be used because they are the most important for the determination of trace elements. Competitive ligand ex- change-adsorptive cathodic stripping voltammetry, which should be considered an equilibrium technique rather than a dynamic method, will be also discussed because the complexing parameters may be affected by some kinetic limitations if equilibrium before analysis is not attained and/or the flux of the adsorbed complex is in fluenced by the lability of the natural complexes in the water sample. For a correct data interpretation and system characterization the comparison of results obtained from different techniques seems essential in the articulation of a serious discussion of their meaning

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council

Chemistry, Toxicity, and Bioavailability of Copper and Its Relationship to Regulation in The Marine Environment

this report. The final report was prepared from this material, from individual notes, and from material in the open scientific literature. The workshop program was as follows: WORKSHOP AGENDA ONR Workshop on Chemistry, Toxicity, and Bioavailability of Copper and Its Relationship to Regulation in the Marine Environment 0800 Registration 0830 Welcome an

The winter air-water CO2, net flux is not significant in the Gulf of California to the north of 30°N

It has been reported that in the Gulf of California tidal energy dissipates at great rates from the region of the midrift islands to the north, with practically no dissipation in the central and southern regions of the gulf. It has also been reported that due to this energy dissipation, in places like Canal de Ballenas, strong water column mixing produces greater CO2, partial pressure (pCO2,) in the surface seawater than in the atmosphere, even during summer. This causes the sea to be a source of CO2, to the atmosphere. We characterized the spatial distribution of surface pH and pCO2, under "winter" conditions, in order to explore the possibility of the role of the northern Gulf of California (NGC), north of 30ºN, as a source of CO2, to the atmosphere. Our results do not support the hypothesis of a significant air-water CO2, flux in the NGC. Mean surface pC02, during winter 1996 was 355 µatm, with a standard error (s n–0.5) of 5 µatm. This mean was not significantly different from the atmospheric value, at 95% confidence level. Thus, the NGC acts neither as a source nor a sink of CO2

Mixing in the region of the midrift islands of the Gulf of California: effect on surface pCO2

Surface seawater carbon dioxide partial pressure (pCO2) and the CO2 flux through the air-sea interface in the region of the midrift islands of the Gulf of California were estimated. We used surface temperature (ºC), salinity and pH data collected during summer 1990, and we assumed a constant specific alkalinity value. Mixing by tide-related phenomena is particularly strong in this region of the gulf, and our objective was to compare the effect of post-spring tides with that of post-neap tides. Carbon dioxide was either near equilibrium or flowing from the water to the atmosphere, even with post-neap tides. Surface cooling, and larger pCO2 and CO2 flux were detected with post-spring tides. relative to post-neap tides (<4 mM m–2 d–1 with post-neap tides. up to 23 mM m–2 d–1 with post-spring tides). There is a fortnightly modulation of the CO2 system in the surface waters of this region due to the spring-neap tide sequence. Tidal mixing is a “physical pump” that carries CO2 efficiently from intermediate depths (500 m) to the atmosphere in this region of the gulf.