The extent to which counterions bind to polyelectrolytes influences a variety of polymer-based applications, including polyelectrolyte enhanced ultrafiltration and forward osmosis using polyelectrolytes as draw agents. Potentiometric titrations of poly (2-vinylpyridine) (P2VP), poly (3-vinylpyridine) (P3VP), and poly (4-vinylpydine) (P4VP) were performed using HBr, HCl, HNO 3 , and HClO 4 in both the presence and absence of added NaCl. Because of the systematic differences among the three polyelectrolytes, titration results provide insight into the role of polymer structure in the relative extents to which various counterions bind. Titration data reveal that ionization properties vary as functions of polymer investigated, titrant used, degree of protonation, and added salt concentration. Acid dissociation constants of the pyridinium moieties were found to generally increase with increasing degree of protonation, though appreciable differences were exhibited among the three polymers investigated. For all three polymers, Cl − demonstrated the lowest affinity for the charged pyridinium residues, while the affinities associated with Br − and 3 NO − were nearly identical to each other. The relative extent of binding for 4 CIO − varied across the polymers investigated, and was greatest for P4VP.
AimsThe objective of this systematic review is to determine with the highest accuracy the average radial artery (RA) diameter overall and in certain subgroups. The aim of this study is to provide assistance in the development of fitting transradial devices, an increasingly popular intervention.MethodsSeveral databases were used to extract appropriate studies highlighting RA diameter. Databases used in the generation of this study were Ovid EBM Reviews, Ovid Embase, Ovid Medline, Scopus and Web of Science Core Collection. RA diameter was determined overall, in males versus females, adults only, adults+children, in the presence of comorbidities, and finally RA diameter in the context of various vasodilators.ResultsA total of 71 studies were included. The average RA diameter overall was determined to be 2.62±0.15 mm in children+adults and 2.70±0.15 mm in adults only. In comparison to an RA diameter of 2.68±0.24 mm in adult males, the diameter was found to be 2.27±0.27 mm in adult females (p=0.028). As for comorbidities, the mean RA diameter in adult patients with hypertension and congestive heart failure was 2.72±0.37 mm and 2.80±0.25 mm, respectively. Finally, the mean RA diameter with nitrate and angiotensin-converting enzyme (ACE) inhibitor use was 2.97±0.53 mm and 2.82±0.29 mm respectively. For comparison, the average outer diameter of a 5 French introducer sheath is 2.29 mm and a 6 French introducer sheath is 2.62 mm.ConclusionsThe findings presented in this study will help determine the most appropriate transradial device to use in several different populations in the context of vasodilator usage or the absence thereof.
Highlights In the evaluation of a first seizure, the capture of epileptiform discharges is increased with 24-hour EEG recordings. This likely stems from a combination of increased sampling and robust sleep recording. Subtle seizures were also recorded by prolonging the EEG in a minority of first seizure presentations.
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