Identifiable Acetylene Features Predicted for Young Earth-like Exoplanets with Reducing Atmospheres Undergoing Heavy Bombardment

The chemical environments of young planets are assumed to be largely influenced by the impacts of bodies lingering on unstable trajectories after the dissolution of the protoplanetary disk. We explore the chemical consequences of impacts within the context of reducing planetary atmospheres dominated by carbon monoxide, methane, and molecular nitrogen. A terawatt high-power laser was selected in order to simulate the airglow plasma and blast wave surrounding the impactor. The chemical results of these experiments are then applied to a theoretical atmospheric model. The impact simulation results in substantial volume mixing ratios within the reactor of 5% hydrogen cyanide (HCN), 8% acetylene (C2H2), 5% cyanoacetylene (HC3N), and 1% ammonia (NH3). These yields are combined with estimated impact rates for the early Earth to predict surface boundary conditions for an atmospheric model. We show that impacts might have served as sources of energy that would have led to steady-state surface quantities of 0.4% C2H2, 400 ppm HCN, and 40 ppm NH3. We provide simulated transit spectra for an Earth-like exoplanet with this reducing atmosphere during and shortly after eras of intense impacts. We predict that acetylene is as observable as other molecular features on exoplanets with reducing atmospheres that have recently gone through their own "heavy bombardments," with prominent features at 3.05 and 10.5 μm

Phylogenetic Analysis of the Complete Mitochondrial Genome of Madurella mycetomatis Confirms Its Taxonomic Position within the Order Sordariales

Background: Madurella mycetomatis is the most common cause of human eumycetoma. The genus Madurella has been characterized by overall sterility on mycological media. Due to this sterility and the absence of other reliable morphological and ultrastructural characters, the taxonomic classification of Madurella has long been a challenge. Mitochondria are of monophyletic origin and mitochondrial genomes have been proven to be useful in phylogenetic analyses. Results: The first complete mitochondrial DNA genome of a mycetoma-causative agent was sequenced using 454 sequencing. The mitochondrial genome of M. mycetomatis is a circular DNA molecule with a size of 45,590 bp, encoding for the small and the large subunit rRNAs, 27 tRNAs, 11 genes encoding subunits of respiratory chain complexes, 2 ATP synthase subunits, 5 hypothetical proteins, 6 intronic proteins including the ribosomal protein rps3. In phylogenetic analyses using amino acid sequences of the proteins involved in respiratory chain complexes and the 2 ATP synthases it appeared that M. mycetomatis clustered together with members of the order Sordariales and that it was most closely related to Chaetomium thermophilum. Analyses of the gene order showed that within the order Sordariales a similar gene order is found. Furthermore also the tRNA order seemed mostly conserved. Conclusion: Phylogenetic analyses of fungal mitochondrial genomes confirmed that M. mycetomatis belongs to the order of Sordariales and that it was most closely related to Chaetomium thermophilum, with which it also shared a comparable gene and tRNA order

Endovascular Repair of a Chronic AV Fistula Presenting as Post-Partum High Output Heart Failure

: Introduction: Acute injury to the large vessels is the most feared of diagnoses for a spinal surgeon, but far more common is the delayed presentation of arteriovenous fistula (AVF) formation. The mean time to diagnosis of an AV fistula in this scenario is just over 1 month. Treatment can include both open and endovascular repair. Report: This study presents a case of an otherwise healthy 39-year-old woman who initially presented with orthopnea, leg edema, and a presumptive diagnosis of post-partum cardiomyopathy. Cardiac investigations revealed high output cardiac failure and an abdominal CT scan confirmed an arterial venous fistula from the left common iliac artery to left common iliac vein. The patient maintained a cardiac output three times normal prior to her definitive treatment. This high flow physiology caused unique challenges for the endovascular procedure as the stent graft collapsed and distorted toward the iliac side wall. The AV fistula was eventually covered successfully and post-operative studies show no further fistula and normal cardiac function. This case demonstrates an unanticipated effect of very high flows of stent graft deployment. Discussion: Extreme high flow AV fistulas can present as unexpected challenges to endovascular repair. These issues may be ameliorated by techniques such as controlled hypotension, adenosine, ventricular pacing, or proximal balloon occlusion. Keywords: Arteriovenous fistula, High output heart failure, Iatrogenic injury, Lumbar discectomy, Pregnanc