Cell-wall polysaccharides play an important role in decay resistance of Sphagnum and actively depressed decomposition in vitro

Sphagnum-dominated peatlands head the list of ecosystems with the largest known reservoirs of organic carbon (C). The bulk of this C is stored in decomposition-resistant litter of one bryophyte genus: Sphagnum. Understanding how Sphagnum litter chemistry controls C mineralization is essential for understanding potential interactions between environmental changes and C mineralization in peatlands. We aimed to separate the effects of phenolics from structural polysaccharides on decay of Sphagnum. Wemeasured aerobic microbial respiration of different moss litter types in a lab. We used chemical treatments to step-wise remove the chemical compounds thought to be important in decay-resistance in three taxonomically distant moss genera. We also focused on the effect of Sphagnum-specific cell-wall pectin-like polysaccharides (sphagnan) on C and N mineralization. Removing polymeric lignin-like phenolics had only negligible effects on C mineralization of Sphagnum litter, but increased mineralization of two other bryophyte genera, suggesting a minor role of these phenolics in decay resistance of Sphagnum but a major role of cell-wall polysaccharides. Carboxyl groups of pectin-like polysaccharides represented a C-source in non-Sphagnum litters but resisted decay in Sphagnum. Finally, isolated sphagnan did not serve as C-source but inhibited C and N mineralization instead, reminiscent of the effects reported for phenolics in other ecosystems. Our results emphasize the role of polysaccharides in resistance to, and active inhibition of, microbial mineralization in Sphagnum-dominated litter. As the polysaccharides displayed decay-inhibiting properties hitherto associated with phenolics (lignin, polyphenols), it raises the question if polysaccharide- dominated litter also shares similar environmental controls on decomposition, such as temperature or nutrient and water availabilit

Acute myocardial infarction in the elderly

Contains fulltext : 153455.pdf (publisher's version ) (Open Access

Primary angioplasty: Preprocedural pharmacological therapy

Primary coronary angioplasty has been shown to be an effective reperfusion therapy for patients with acute myocardial infarction, not only for those who present to PTCA centres but also for patients who present to hospitals without angioplasty facilities. With the increasing use of primary angioplasty more patients will be transferred to a (tertiary) PTCA centre. An increase in treatment delay is associated with a worse clinical outcome. The importance of an open infarct-related vessel at acute angiography is becoming clear. Pharmacological pretreatment of patients during transportation to a PTCA centre with the aim to open the infarct-related vessel in advance might be beneficial. Glycoprotein IIb/IIIa receptor blockers seem to be the agents of choice for facilitated PTCA. The safety and (cost) effectiveness of this pretreatment of patients transported to undergo primary angioplasty remain to be evaluatedPrimary coronary angioplasty has been shown to be an effective reperfusion therapy for patients with acute myocardial infarction, not only for those who present to PTCA centres but also for patients who present to hospitals without angioplasty facilities. With the increasing use of primary angioplasty more patients will be transferred to a (tertiary) PTCA centre. An increase in treatment delay is associated with a worse clinical outcome. The importance of an open infarct-related vessel at acute angiography is becoming clear. Pharmacological pretreatment of patients during transportation to a PTCA centre with the aim to open the infarct-related vessel in advance might be beneficial. Glycoprotein IIb/IIIa receptor blockers seem to be the agents of choice for facilitated PTCA. The safety and (cost) effectiveness of this pretreatment of patients transported to undergo primary angioplasty remain to be evaluate

The ionized nebula surrounding the red supergiant W26 in Westerlund 1

We present Hα images of an ionized nebula surrounding the M2-5Ia red supergiant (RSG) W26 in the massive star cluster Westerlund 1. The nebula consists of a circumstellar shell or ring ∼0.1 pc in diameter and a triangular nebula ∼0.2 pc from the star that in high-resolution Hubble Space Telescope images shows a complex filamentary structure. The excitation mechanism of both regions is unclear since RSGs are too cool to produce ionizing photons and we consider various possibilities. The presence of the nebula, high stellar luminosity and spectral variability suggests that W26 is a highly evolved RSG experiencing extreme levels of mass-loss. As the only known example of an ionized nebula surrounding an RSG W26 deserves further attention to improve our understanding of the final evolutionary stages of massive stars

Long-term follow-up of quality of life in high-risk patients undergoing transcatheter aortic valve implantation for symptomatic aortic valve stenosis

Background Transcatheter aortic valve implantation (TAVI) has become the standard treatment for patients with severe symptomatic aortic stenosis (AS) considered at very high risk for surgical aortic valve replacement. The purpose of this sub-study was to evaluate long-term (> 4 years) health-related quality of life (QoL) in octogenarians who underwent TAVI. Methods A single center observational registry in twenty patients who underwent frame analysis assessment = 4 years after TAVI. Health-related QoL was evaluated, using the Short Form-36 (SF-36), the EuroQoL-5D (EQ-5D) and the visual analogue score (EQ-VAS) questionnaires. Results The mean SF-36 subscale scores at follow-up were physical functioning 40.8 ± 26.3, role physical functioning 67.7 ± 34.9, vitality 54.6 ± 21.6, general health 52.1 ± 20.4, social functioning 63.8 ± 37.7, role emotional functioning 70.2 ± 36.0, mental health 73.2 ± 23.3 and bodily pain 80.9 ± 22.9. The mean EQ-VAS score > 4 years after TAVI was 64.7 ± 15.1. With respect to functional class, 80% of the patients were in NYHA class I/II at follow-up compared to 15% prior to TAVI. Conclusions This sub-study reports a significant improvement in functional class (NYHA) in a selected group of very elderly patients > 4 years after TAVI. Furthermore, all patients showed a satisfactory QoL despite their age and multiple comorbidities. In addition, our study reveals a lower QoL when compared with the general age matched Dutch population

A mid-infrared imaging catalogue of post-asymptotic giant branch stars

The definitive version can be found at: http://onlinelibrary.wiley.com/ Copyright Royal Astronomical SocietyPost-asymptotic giant branch (post-AGB) stars are key objects for the study of the dramatic morphological changes of low- to intermediate-mass stars on their evolution from the AGB towards the planetary nebula stage. There is growing evidence that binary interaction processes may very well have a determining role in the shaping process of many objects, but so far direct evidence is still weak. We aim at a systematic study of the dust distribution around a large sample of post-AGB stars as a probe of the symmetry breaking in the nebulae around these systems. We used imaging in the mid-infrared to study the inner part of these evolved stars to probe direct emission from dusty structures in the core of post-AGB stars in order to better understand their shaping mechanisms. We imaged a sample of 93 evolved stars and nebulae in the mid-infrared using VLT spectrometer and imager for the mid-infrared (VISIR)/VLT, T-Recs/Gemini-South and Michelle/Gemini-North. We found that all the proto-planetary nebulae we resolved show a clear departure from spherical symmetry. 59 out of the 93 observed targets appear to be non-resolved. The resolved targets can be divided into two categories. (i) The nebulae with a dense central core, that are either bipolar and multipolar and (ii) the nebulae with no central core, with an elliptical morphology. The dense central torus observed likely hosts binary systems which triggered fast outflows that shaped the nebulae.Peer reviewe

Invasive left ventricle pressure-volume analysis: overview and practical clinical implications

Ventricular pressure-volume (PV) analysis is the reference method for the study of cardiac mechanics. Advances in calibration algorithms and measuring techniques brought new perspectives for its application in different research and clinical settings. Simultaneous PV measurement in the heart chambers offers unique insights into mechanical cardiac efficiency. Beat to beat invasive PV monitoring can be instrumental in the understanding and management of heart failure, valvular heart disease, and mechanical cardiac support. This review focuses on intra cardiac left ventricular PV analysis principles, interpretation of signals, and potential clinical applications