Redox chemistry of iron in fog and stratus clouds

The redox chemistry of Fe in fog and cloudwater has been investigated at coastal and inland locations in the Los Angeles basin, in Bakersfield California, and in Delaware Bay. Samples were collected and analyzed for Fe (Fe(II)), Fe(III), total(Fe), sulfur (S(IV), S(VI)), organic ligands (formate, acetate, oxalate), total organic carbon (TOC), pH, major cations (sodium, calcium, magnesium, potassium, ammonium), chloride, sulfate, nitrate, peroxides, and aldehydes (HCHO); the amount of sunlight was also measured. The ratio Fe(II)/Fe(total) varied between 0.02 and 0.55. The concentration of Fe(II) varied between 0.1 and 5 micromole, and the concentration of total Fe varied between 2 and 27 micromole. The atmospheric redox cycle of Fe involves both dissolved and aerosol surface species and appears to be related to the presence of organic compounds which act as electron donors for the reduction of Fe(III). Fe(III) reduction is enhanced by light but significant Fe(II) levels were observed in the dark. We suggest that reduction of Fe(III) species by organic electron donors may be an important pathway that affects the speciation of Fe in both urban and rural atmospheres. It is possible that reactions involving Fe and organic compounds might be an important source of carboxylic acids in the troposphere

Mechanism of bidirectional thermotaxis in Escherichia coli.

In bacteria various tactic responses are mediated by the same cellular pathway, but sensing of physical stimuli remains poorly understood. Here, we combine an in-vivo analysis of the pathway activity with a microfluidic taxis assay and mathematical modeling to investigate the thermotactic response of Escherichia coli. We show that in the absence of chemical attractants E. coli exhibits a steady thermophilic response, the magnitude of which decreases at higher temperatures. Adaptation of wild-type cells to high levels of chemoattractants sensed by only one of the major chemoreceptors leads to inversion of the thermotactic response at intermediate temperatures and bidirectional cell accumulation in a thermal gradient. A mathematical model can explain this behavior based on the saturation-dependent kinetics of adaptive receptor methylation. Lastly, we find that the preferred accumulation temperature corresponds to optimal growth in the presence of the chemoattractant serine, pointing to a physiological relevance of the observed thermotactic behavior

Nonperturbative Gauge Fixing and Perturbation Theory

We compare the gauge-fixing approach proposed by Jona-Lasinio and Parrinello, and by Zwanziger (JPLZ) with the standard Fadeev-Popov procedure, and demonstrate perturbative equality of gauge-invariant quantities, up to irrelevant terms induced by the cutoff. We also show how a set of local, renormalizable Feynman rules can be constructed for the JPLZ procedure.Comment: 9 pages, latex, version to appear in Phys. Rev.

First human use of a wireless coplanar energy transfer coupled with a continuous-flow left ventricular assist device

The drive-line to power contemporary ventricular assist devices exiting the skin is associated with infection, and requires a holstered performance of the cardiac pump, which reduces overall quality of life. Attempts to eliminate the drive-line using transcutaneous energy transfer systems have been explored but have not succeeded in viable widespread application. The unique engineering of the coplanar energy transfer system is characterized by 2 large rings utilizing a coil-within-the-coil topology, ensuring robust resonance energy transfer while allowing for a substantial (>6 hours) unholstered circulatory support powered by an implantable battery source. Herein we report the first known human experience with this novel technology, coupled with a continuous-flow assist left ventricular assist device, in 2 consecutive patients evaluated with the primary end-point of system performance at 30 days post-implantation. ispartof: JOURNAL OF HEART AND LUNG TRANSPLANTATION vol:38 issue:4 pages:339-343 ispartof: location:United States status: publishe

Subclinical postoperative atrial fibrillation: a randomized trial

BackgroundPostoperative atrial fibrillation (POAF) is the most common complication of cardiac surgery, requiring interventions and prolonging hospital stay. POAF is associated with increased mortality and a higher rate of systemic thrombo-embolism. The rates of recurrent AF, optimal follow-up and management remain unclear. We aimed to evaluate the incidence of recurrent atrial fibrillation (AF) events, during long term follow-up in patients with POAF following cardiac surgery.MethodsPatients with POAF and a CHA2DS2-VASc score of ≥2 were randomized in a 2:1 ratio to either implantation of a loop recorder (ILR) or ECG monitoring using periodic Holters. Participants were followed prospectively for 2 years. The primary end point was the occurrence of AF longer than 5 min.ResultsThe final cohort comprised of 22 patients, of whom 14 received an ILR. Over a median follow up of 25.7 (IQR of 24.7–44.4) months, 8 patients developed AF, representing a cumulative annualized risk of AF recurrence of 35.7%. There was no difference between ILR (6 participants, 40%) and ECG/Holter (2 participants, 25% p = 0.917). All 8 patients with AF recurrence were treated with oral anticoagulation. There were no cases of mortality, stroke or major bleeding. Two patients underwent ILR explantation due to pain at the implantation site.ConclusionsThe rate of recurrent AF in patients with POAF after cardiac surgery and a CHA2DS2-VASc score of ≥2 is approximately 1 in 3 when followed systematically. Further research is need to assess the role of ILRs in this population

Heritability in genetic heart disease : the role of genetic background

Background Mutations in genes encoding ion channels or sarcomeric proteins are an important cause of hereditary cardiac disease. However, the severity of the resultant disease varies considerably even among those with an identical mutation. Such clinical variation is often thought to be explained largely by differences in genetic background or ` modifier genes'. We aimed to test the prediction that identical genetic backgrounds result in largely similar clinical expression of a cardiac disease causing mutation, by studying the clinical expression of mutations causing cardiac disease in monozygotic twins. Methods We compared first available clinical information on 46 monozygotic twin pairs and 59 control pairs that had either a hereditary cardiomyopathy or channelopathy. Results Despite limited power of this study, we found significant heritability for corrected QT interval (QTc) in long QT syndrome (LQTS). We could not detect significant heritability for structural traits, but found a significant environmental effect on thickness of the interventricular septum in hypertrophic cardiomyopathy. Conclusions Our study confirms previously found robust heritability for electrical traits like QTc in LQTS, and adds information on low or lacking heritability for structural traits in heritable cardiomyopathies. This may steer the search for genetic modifiers in heritable cardiac disease.Peer reviewe

Confinement, chiral symmetry, and the lattice

Two crucial properties of QCD, confinement and chiral symmetry breaking, cannot be understood within the context of conventional Feynman perturbation theory. Non-perturbative phenomena enter the theory in a fundamental way at both the classical and quantum level. Over the years a coherent qualitative picture of the interplay between chiral symmetry, quantum mechanical anomalies, and the lattice has emerged and is reviewed here.Comment: 126 pages, 36 figures. Revision corrects additional typos and renumbers equations to be more consistent with the published versio

Outcomes in Transcatheter Aortic Valve Replacement for Bicuspid Versus Tricuspid Aortic Valve Stenosis

Cardiolog

ECMO for COVID-19 patients in Europe and Israel

Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients