A chemical ionization study of deuteron transfer initiated propene loss from propoxypyridines

AbstractThe mechanism of propene loss from the metastable [M + D]+ ions of isomeric 2-, 3-, and 4-n-propoxypyridines and the related isopropoxypyridines has been examined by chemical ionization (CI) and tandem mass spectrometry in combination with deuterium labeling. The [M + D]+ ions were generated with CD3OD, CD3CN, (CD3)2CO, or pyrrole-D5 (listed in order of increasing proton affinity) as the CI reagent. The results reveal that the deuteron added in the CI process is not interchanged with the hydrogen atoms of the propyl group prior to propene loss from the metastable [M + D]+ ions of the propoxypyridines. The site selective labeling of the α-, β-, or γ-position of the propyl group indicates that the [M + D]+ ions of 2-n-propoxypyridine expel propene with formation of an ion-neutral complex composed of a propyl carbenium ion and 2-pyridone. By contrast, the [M + D]+ ions of 3-n-propoxypyridine expel propene by: (1) Formation of ion-neutral complexes, and (2) a conventional 1,5-hydride shift from the β-position of the n-propyl group to the ring and/or a 1,2-elimination type process. For the 4-isomer, the results suggest the occurrence of propene loss by a 1,2-elimination in addition to the intermediate formation of ion-neutral complexes. Loss of propene with one deuterium atom is the only reaction of the [M + D]+ ions of the isopropoxypyridines labeled at the α-position of the isopropyl group. The results for the isopropoxypyridines labeled with three deuterium atoms at the β-position are consistent with: (1) The loss of propene by ion-neutral complex formation and the occurrence of a substantial isotope effect in the subsequent proton/deuteron transfer within the complex, and/or (2) the loss of propene by a 1,2-elimination type reaction

Gender-partitioned patient medians of serum albumin requested by general practitioners for the assessment of analytical stability

AbstractBackground:Recently, the use of separate gender-partitioned patient medians of serum sodium has revealed potential for monitoring analytical stability within the optimum analytical performance specifications for laboratory medicine. The serum albumin concentration depends on whether a patient is sitting or recumbent during phlebotomy. We therefore investigated only examinations requested by general practitioners (GPs) to provide data from sitting patients.Methods:Weekly and monthly patient medians of serum albumin requested by GP for both male and female patients were calculated from the raw data obtained from three analysers in the hospital laboratory on examination of samples from those &gt;18 years. The half-range of medians were applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated (females/males).Results:The medians for male and female patients were closely related despite considerable variation due to the current analytical variation. This relationship was confirmed by the calculated half-range for the monthly ratio between the genders of 0.44%, which surpasses the optimum analytical performance specification for bias of serum albumin (0.72%). The weekly ratio had a half-range of 1.83%, which surpasses the minimum analytical performance specifications of 2.15%.Conclusions:Monthly gender-partitioned patient medians of serum albumin are useful for monitoring of long-term analytical stability, where the gender medians are two independent estimates of changes in (delta) bias: only results requested by GP are of value in this application to ensure that all patients are sitting during phlebotomy.</jats:sec

Separate patient serum sodium medians from males and females provide independent information on analytical bias

AbstractBackground:During monitoring of monthly medians of results from patients undertaken to assess analytical stability in routine laboratory performance, the medians for serum sodium for male and female patients were found to be significantly related.Methods:Daily, weekly and monthly patient medians of serum sodium for both male and female patients were calculated from results obtained on samples from the population &gt;18 years on three analysers in the hospital laboratory. The half-range of medians was applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated.Results:The medians of both genders demonstrated dispersions over time, but they were closely connected in like patterns, which were confirmed by the half-range of the ratios of medians for males and females that varied from 0.36% for daily, 0.14% for weekly and 0.036% for monthly ratios over all instruments.Conclusions:The tight relationship between the gender medians for serum sodium is only possible when raw laboratory data are used for calculation. The two patient medians can be used to confirm both and are useful as independent estimates of analytical bias during constant calibration periods. In contrast to the gender combined median, the estimate of analytical bias can be confirmed further by calculation of the ratios of medians for males and females.</jats:sec

”Authentic Microteaching” som akademisk lærings- og undervisningsmodel

Universitetsuddannelsen i idræt integrerer læring af praktiske kompetencer og akademisk faglig fordybelse. I denne artikel præsenterer vi ”authentic microtea-ching” som model, hvor medbestemmelse og formidlingsdimensionen indgår som centrale fokusområder i vores undervisning. Vores empiriske erfaringer med at ud-vikle modellen samt det lærings- og uddannelsesstrategiske sigte beskrives med udgangspunkt i et specifikt kursus, hvor vores studerende via små trefasede forløb bevæger sig fra at være deltagere i undervisning til selv at være formidlere af det faglige indhold i virkelighedsnære undervisningssituationer. I første fase introduce-res de studerende til praksisområdet i korte forløb tilrettelagt af universitetets un-dervisere, mens anden fase tager udgangspunkt i ”reciprocal peer teaching”, hvor de studerende underviser hinanden og udvikler deres egen praksis organiseret ud fra ”microteaching”-modellen. Tredje fase inkluderer korte undervisningsforløb med elever fra gymnasieskolen som deltagere i virkelighedsnære situationer ud fra ”au-tenthic pedagogy” og tilhørende refleksionspapirer (mini-underviser-portfolier) som parallel fordybelsesaktivitet