Magnetic Field Stimulated Transitions of Excited States in Fast Muonic Helium Ions

It is shown that one can stimulate, by using the present-day laboratory magnetic fields, transitions between the $lm$ sub-levels of fast $\mu He^+$ ions formating in muon catalyzed fusion. Strong fields also cause the self-ionization from highly excited states of such muonic ions. Both effects are the consequence of the interaction of the bound muon with the oscillating field of the Stark term coupling the center-of-mass and muon motions of the $\mu He^+$ ion due to the non-separability of the collective and internal variables in this system. The performed calculations show a possibility to drive the population of the $lm$ sub-levels by applying a field of a few $Tesla$, which affects the reactivation rate and is especially important to the $K\alpha$ $x$-ray production in muon catalyzed fusion. It is also shown that the $2s-2p$ splitting in $\mu He^+$ due to the vacuum polarization slightly decreases the stimulated transition rates.Comment: 5 figure

Myocardial fibrosis in asymptomatic and symptomatic chronic severe primary mitral regurgitation and relationship to tissue characterisation and left ventricular function on cardiovascular magnetic resonance

Background: Myocardial fbrosis occurs in end-stage heart failure secondary to mitral regurgitation (MR), but it is not known whether this is present before onset of symptoms or myocardial dysfunction. This study aimed to characterise myocardial fbrosis in chronic severe primary MR on histology, compare this to tissue characterisation on cardiovascular magnetic resonance (CMR) imaging, and investigate associations with symptoms, left ventricular (LV) function, and exercise capacity. Methods: Patients with class I or IIa indications for surgery underwent CMR and cardiopulmonary exercise testing. LV biopsies were taken at surgery and the extent of fbrosis was quantifed on histology using collagen volume fraction (CVFmean) compared to autopsy controls without cardiac pathology. Results: 120 consecutive patients (64±13 years; 71% male) were recruited; 105 patients underwent MV repair while 15 chose conservative management. LV biopsies were obtained in 86 patients (234 biopsy samples in total). MR patients had more fbrosis compared to 8 autopsy controls (median: 14.6% [interquartile range 7.4–20.3] vs. 3.3% [2.6–6.1], P<0.001); this diference persisted in the asymptomatic patients (CVFmean 13.6% [6.3–18.8], P<0.001), but severity of fbrosis was not signifcantly higher in NYHA II-III symptomatic MR (CVFmean 15.7% [9.9–23.1] (P=0.083). Fibrosis was patchy across biopsy sites (intraclass correlation 0.23, 95% CI 0.08–0.39, P=0.001). No signifcant relationships were identifed between CVFmean and CMR tissue characterisation [native T1, extracellular volume (ECV) or late gadolinium enhancement] or measures of LV function [LV ejection fraction (LVEF), global longitudinal strain (GLS)]. Although the range of ECV was small (27.3±3.2%), ECV correlated with multiple measures of LV function (LVEF: Rho=−0.22, P=0.029, GLS: Rho=0.29, P=0.003), as well as NTproBNP (Rho=0.54, P<0.001) and exercise capacity (%PredVO2max: R=−0.22, P=0.030). Conclusions: Patients with chronic primary MR have increased fbrosis before the onset of symptoms. Due to the patchy nature of fbrosis, CMR derived ECV may be a better marker of global myocardial status. Clinical trial registration Mitral FINDER study; Clinical Trials NCT02355418, Registered 4 February 2015, https://clinicaltr ials.gov/ct2/show/NCT0235541

Viking Age garden plants from southern Scandinavia: diversity, taphonomy and cultural aspects

Plant finds recovered from archaeological sites in southern Scandinavia dated to the Viking Age reflect the diversity of useful plants that were cultivated and collected. This review presents the results of 14 investigations of deposits that are dated between AD 775 and 1050. The site types are categorized as agrarian, urban, military and burials. Garden plants are unevenly distributed, as the greatest diversity is recorded in features from urban contexts. We argue that taphonomic processes played an important role in the picture displayed. Archaeobotanical research results from neighbouring regions suggest that Viking Age horticulture has its roots in older traditions, and that the spectrum of garden plants is influenced by central and north-western European horticultural customs, which were to a great extent shaped by Roman occupation

Myocardial fibrosis in asymptomatic and symptomatic chronic severe primary mitral regurgitation and relationship to tissue characterisation and left ventricular function on cardiovascular magnetic resonance

Background: Myocardial fbrosis occurs in end-stage heart failure secondary to mitral regurgitation (MR), but it is not known whether this is present before onset of symptoms or myocardial dysfunction. This study aimed to characterise myocardial fbrosis in chronic severe primary MR on histology, compare this to tissue characterisation on cardiovascular magnetic resonance (CMR) imaging, and investigate associations with symptoms, left ventricular (LV) function, and exercise capacity. Methods: Patients with class I or IIa indications for surgery underwent CMR and cardiopulmonary exercise testing. LV biopsies were taken at surgery and the extent of fbrosis was quantifed on histology using collagen volume fraction (CVFmean) compared to autopsy controls without cardiac pathology. Results: 120 consecutive patients (64±13 years; 71% male) were recruited; 105 patients underwent MV repair while 15 chose conservative management. LV biopsies were obtained in 86 patients (234 biopsy samples in total). MR patients had more fbrosis compared to 8 autopsy controls (median: 14.6% [interquartile range 7.4–20.3] vs. 3.3% [2.6–6.1], P<0.001); this diference persisted in the asymptomatic patients (CVFmean 13.6% [6.3–18.8], P<0.001), but severity of fbrosis was not signifcantly higher in NYHA II-III symptomatic MR (CVFmean 15.7% [9.9–23.1] (P=0.083). Fibrosis was patchy across biopsy sites (intraclass correlation 0.23, 95% CI 0.08–0.39, P=0.001). No signifcant relationships were identifed between CVFmean and CMR tissue characterisation [native T1, extracellular volume (ECV) or late gadolinium enhancement] or measures of LV function [LV ejection fraction (LVEF), global longitudinal strain (GLS)]. Although the range of ECV was small (27.3±3.2%), ECV correlated with multiple measures of LV function (LVEF: Rho=−0.22, P=0.029, GLS: Rho=0.29, P=0.003), as well as NTproBNP (Rho=0.54, P<0.001) and exercise capacity (%PredVO2max: R=−0.22, P=0.030). Conclusions: Patients with chronic primary MR have increased fbrosis before the onset of symptoms. Due to the patchy nature of fbrosis, CMR derived ECV may be a better marker of global myocardial status. Clinical trial registration Mitral FINDER study; Clinical Trials NCT02355418, Registered 4 February 2015, https://clinicaltr ials.gov/ct2/show/NCT0235541