Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a ...challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs.A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible.In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62-0.71 for existing, and 0.74-0.76 for new PAQs. Median validity coefficients ranged from 0.30-0.39 for existing, and from 0.25-0.41 for new PAQs.Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument.
Background
The newly introduced nonthermal pulsed field ablation (PFA) is a promising technology to achieve fast pulmonary vein isolation (PVI) with high acute success rates and good safety features. ...However, previous studies have shown that very high power short duration ablation (VHPSD) is also highly effective and fast to achieve PVI with potentially less arrhythmia recurrence compared to conventional radiofrequency ablation. Data comparing PFA to VHPSD‐PVI is lacking.
Objective
This study compared procedural and outcome data for PFA‐PVI to VHPSD‐PVI in patients with paroxysmal or persistent atrial fibrillation (PAF/persAF).
Methods
Consecutive patients undergoing de novo PVI (PFA or VHPSD) were included in this analysis. For PFA‐PVI a pentaspline 20 electrode catheter was used. For VHPSD‐PVI an enhanced irrigated catheter with a power setting of 70 W/7 s (70 W/5 s at posterior wall) was employed in conjunction with electro‐anatomical mapping. All procedures were performed in deep analgo‐sedation.
Results
A total of n = 114 patients (n = 5750% PFA, n = 1730% PAF; n = 4070% persAF) were included in this analysis. PVI was successful in all patients. The PFA group revealed a significantly shorter procedure duration (65 ± 17 min vs. 95 ± 23 min, p < 0.01) but longer fluoroscopy time (PFA 15 ± 5 min and VHPSD 12 ± 3 min; p < 0.001). At follow‐up after median 125 days (interquartile range: 109–162) n = 46 PFA (80.7%) and n = 44 VHPSD pts (77.2%) were free from atrial arrhythmia after a single procedure (p = 0.819).
Two tamponades occurred in the PFA while in VHPSD two pts suffered groin bleedings. One clinically nonsignificant PV stenosis occurred in the VHPSD group.
Conclusion
Pulsed‐field ablation and VHPSD‐PVI seem to be highly effective and safe to achieve PVI in the setting of PAF and persAF with comparable arrhythmia‐free survival. However, procedure duration for PFA PVI is significantly shorter and therefore may be of potential benefit. Compared to PFA VHPSD‐PVI might ensure information on left atrial substrate allowing to target concomitant secondary tachycardias.
PFA versus VHPSD for PVI.
Mouse embryonic stem (ES) cells grown in serum exhibit greater heterogeneity in morphology and expression of pluripotency factors than ES cells cultured in defined medium with inhibitors of two ...kinases (Mek and GSK3), a condition known as “2i” postulated to establish a naive ground state. We show that the transcriptome and epigenome profiles of serum- and 2i-grown ES cells are distinct. 2i-treated cells exhibit lower expression of lineage-affiliated genes, reduced prevalence at promoters of the repressive histone modification H3K27me3, and fewer bivalent domains, which are thought to mark genes poised for either up- or downregulation. Nonetheless, serum- and 2i-grown ES cells have similar differentiation potential. Precocious transcription of developmental genes in 2i is restrained by RNA polymerase II promoter-proximal pausing. These findings suggest that transcriptional potentiation and a permissive chromatin context characterize the ground state and that exit from it may not require a metastable intermediate or multilineage priming.
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▸ High-resolution genome-wide transcriptome and epigenome of naive pluripotency ▸ Reduced H3K27me3 at promoters and fewer bivalent domains in naive ES cells ▸ Reduced lineage priming and increased RNA polymerase II pausing in the naive state ▸ Naive ES cells show no delay in differentiation
Ground state pluripotency is characterized by a permissive chromatin context, but gene expression is not promiscuous due to the high prevalence of promoter-proximal pausing of transcription.
Lead Toxicity in Plants Küpper, Hendrik
Lead: Its Effects on Environment and Health,
04/2017, Volume:
17
Book Chapter, Journal Article
This review looks critically at the relevance of lead (Pb2+) toxicity and proposed mechanisms of Pb2+ -induced stress in algae and higher plants. As a basis, the current main sources of Pb2+ ...contamination in the environment are presented, which include agriculture, industry, and road traffic. Further, bioavailability of lead is discussed as a basis for evaluating the environmental relevance of the many studies on lead toxicity that have been published in the past decades. These studies suggest three main mechanisms of toxicity of Pb2+: inhibition of photosynthesis, oxidative stress, and "genotoxicity" including DNA damage and defects in mitosis. Looking at the applied concentration ranges in these studies reveals that likely the defects in mitosis are the environmentally most relevant effects. In contrast, inhibition of photosynthetic light reactions is far less efficient with Pb2+ compared to other metal ions, so that for Pb2+ toxicity it seems environmentally not relevant. As a conclusion and outlook, a direction of future studies towards establishment of reliable concentration thresholds of the various toxic effects and their causal interconnection is suggested.
We present a novel generic framework to approximate the nonequilibrium steady states of dissipative quantum many-body systems. It is based on the variational minimization of a suitable norm of the ...quantum master equation describing the dynamics. We show how to apply this approach to different classes of variational quantum states and demonstrate its successful application to a dissipative extension of the Ising model, which is of importance to ongoing experiments on ultracold Rydberg atoms, as well as to a driven-dissipative variant of the Bose-Hubbard model. Finally, we identify several advantages of the variational approach over previously employed mean-field-like methods.
Abstract
Introduction
Pulmonary vein isolation (PVI) remains the cornerstone in the treatment of atrial fibrillation (AF). PVI using cryoballoon (CB) technology has emerged as a standard procedure in ...many centers. Recently, pulsed field ablation (PFA) has been introduced and used to achieve PVI. First data show high acute and favorable long‐term outcomes. So far, data comparing these new “single shot” devices are sparse. We sought to compare procedural and outcome data for first time PFA users versus CB in patients undergoing de novo PVI. Furthermore, potentially postprocedural discomfort and affection of autonomic ganglia were assessed.
Methods and Results
A retrospective analysis and comparison of all de novo PVIs with PFA and CB was performed. Furthermore, PFA PVI learning curve was evaluated. During follow‐up, repeat outpatient visits and Holter electrocardiogram were performed to analyze arrhythmia‐free survival. Discomfort analysis was obtained by prescribed analgesic medication within first 48 h after PVI. Potential changes in heart rate (HR) between baseline and at 3‐month follow‐up were evaluated. A total of 108 patients (54 PFA and 54 CB; PFA; 33 (30%) female) with paroxysmal and persistent AF were analyzed. Type of AF was comparable (Patients suffering from PAF: PFA: 16 (30%), CB: 17 (31%), p = 1.0). In 107 (99%) patients, successful PVI was achieved. Transient phrenic palsy omitted complete PVI in one CB patient. A trend for a shorter overall procedure duration was observed in the PFA group (PFA: 64.5 ± 17.5 min; CB: 73.0 ± 24.8 min;
p
= 0.07). Excluding LA mapping time (first 14 cases), procedure time was significantly shorter using PFA (PFA: 58.0 ± 12.5 min, CB: 73.0 ± 24.8 min,
p
= 0.0001). Fluoroscopy time was significantly longer for PFA (PFA: 15.3 ± 4.7 min, CB: 12.3 ± 5.3 min;
p
= 0.001), but significantly less contrast medium was used (PFA: 12 ± 6 mL; CB: 51 ± 29 mL,
p
< 0.0001). Subgroup analysis of the PFA group revealed a significant shortening of procedure duration over time (first tertile: 72.7 ± 13.5 min, second tertile: 67.3 ± 21.7 min, third tertile: 53.4 ± 9.8 min, first vs. third tertile
p
< 0.0001). Two cardiac tamponades occurred in the PFA group (
p
= 0.495), of which one was most likely related to complex transseptal puncture. In the first 48 h after PVI, the number of prescribed analgesics due to postprocedural pain was equal between both groups (PFA: 7 (13%) patients, CB: 10 (19%) patients,
p
= 0.598). After a FU of 273 ± 129 days, 35 of 47 patients (74%) after PFA and 36 of 50 patients (72%) after CB PVI were free of any atrial arrhythmia (HR: 0.98,
p
= 0.88). Only in the PFA group, a significant increase in HR 3 months after PVI was observed (pre‐PVI: 61 ± 8 beats/min, post‐PVI: 65 ± 9 beats/min,
p
= 0.008).
Conclusion
The new PFA technology is equally effective and safe as compared to CB for complete PVI with potentially shorter procedure time and significantly less contrast medium. However, AF recurrence rates after PFA PVI seem to be comparable to CB PVI.
Spatial distribution and leakage effects are of policy concern and increasingly discussed in the economics literature. We study Europe's most aggressive recent air pollution regulation: low-emission ...zones (LEZs) are areas in which vehicular access is allowed only to vehicles that emit low levels of PM₁₀-Using new administrative data sets from Germany, we assess the effect of LEZs on air pollution and the spatial substitution effects in green versus dirty vehicles. Back of the envelope calculations suggest that health benefits of roughly 2 billion dollars have come at a cost of 1 billion dollars for upgrading the fleet of vehicles.
The majority of common stocks that have appeared in the Center for Research in Security Prices (CRSP) database since 1926 have lifetime buy-and-hold returns less than one-month Treasuries. When ...stated in terms of lifetime dollar wealth creation, the best-performing 4% of listed companies explain the net gain for the entire US stock market since 1926, as other stocks collectively matched Treasury bills. These results highlight the important role of positive skewness in the distribution of individual stock returns, attributable to skewness in monthly returns and to the effects of compounding. The results help to explain why poorly diversified active strategies most often underperform market averages.
In the electrophilic C−H borylation of electron‐rich aromatic compounds with catecholborane, the catalytic generation of the boron electrophile is initiated by heterolysis of the B−H bond by various ...Lewis and Brønsted acids, with a boronium ion formed exclusively. After ligand dissociation, the corresponding borenium ion undergoes regioselective electrophilic aromatic substitution on aniline derivatives as well as nitrogen‐containing heterocycles. The catalysis is optimized using B(C6F5)3 as the initiator and proceeds without the addition of an external base or dihydrogen acceptor. Temperatures above 80 °C are generally required to secure efficient turnover in these Friedel–Crafts‐type reactions. Mechanistic experiments reveal that regeneration of the boronium/borenium ion with dihydrogen release is rate‐determining. This finding finally led to the discovery that, with added alkenes, catalytic C−H borylations can, for the first time, be carried out at room temperature.
Be positive: B(C6F5)3 initiates the acceptor‐free electrophilic aromatic substitution of anilines and azoles (and thiophenes) with catecholborane (catBH). Elevated reactions temperatures are required to overcome the rate‐determining step—the regeneration of the boronium/borenium ion. The addition of alkenes, for example, norbornene (nbe), changes the situation dramatically, with the reaction occurring at ambient temperature. PG=protecting group.
Superacidic media became famous in connection with carbocations. Yet not all reactive intermediates can be generated, characterized, and eventually isolated from these Brønsted acid/Lewis acid ...cocktails. The counteranion, that is the conjugate base, in these systems is often too nucleophilic and/or engages in redox chemistry with the newly formed cation. The Brønsted acidity, especially superacidity, is in fact often not even crucial unless protonation of extremely weak bases needs to be achieved. Instead, it is the chemical robustness of the aforementioned counteranion that determines the success of the protolysis. The advent of molecular Brønsted superacids derived from weakly coordinating, redox-inactive counteranions that do withstand the enormous reactivity of superelectrophiles such as silicon cations completely changed the whole field. This Perspective summarizes general aspects of medium and molecular Brønsted acidity and shows how applications of molecular Brønsted superacids have advanced from stoichiometric reactions to catalytic processes involving protons and in situ generated superelectrophiles.
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