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The rise of inorganic-biological hybrid organisms for solar-to-chemical production has spurred mechanistic investigations into the dynamics of the biotic-abiotic interface to drive the development of next-generation systems. The model system, Moorella thermoacetica-cadmium sulfide (CdS), combines an inorganic semiconductor nanoparticle light harvester with an acetogenic bacterium to drive the photosynthetic reduction of CO2 to acetic acid with high efficiency. In this work, we report insights into this unique electrotrophic behavior and propose a charge-transfer mechanism from CdS to M. thermoacetica Transient absorption (TA) spectroscopy revealed that photoexcited electron transfer rates increase with increasing hydrogenase (H2ase) enzyme activity. On the same time scale as the TA spectroscopy, time-resolved infrared (TRIR) spectroscopy showed spectral changes in the 1,700-1,900-cm-1 spectral region. The quantum efficiency of this system for photosynthetic acetic acid generation also increased with increasing H2ase activity and shorter carrier lifetimes when averaged over the first 24 h of photosynthesis. However, within the initial 3 h of photosynthesis, the rate followed an opposite trend: The bacteria with the lowest H2ase activity photosynthesized acetic acid the fastest. These results suggest a two-pathway mechanism: a high quantum efficiency charge-transfer pathway to H2ase generating H2 as a molecular intermediate that dominates at long time scales (24 h), and a direct energy-transducing enzymatic pathway responsible for acetic acid production at short time scales (3 h). This work represents a promising platform to utilize conventional spectroscopic methodology to extract insights from more complex biotic-abiotic hybrid systems.

Epidermal inclusion cysts (EIC) of the breast are uncommon and can occur after previous surgery or trauma. Here we discuss a case of massive bilateral multiple EIC of the breast presenting seven years after reduction mammaplasty. This report highlights the importance of accurate diagnosis and management of this rare condition. [ABSTRACT FROM AUTHOR]

We present two cases of acute aortic syndromes (AAS), involving an aberrant right subclavian artery (ARSA) with associated Kommerell's diverticulae (KD). One of the cases involves a penetrating aortic ulcer in patients with an ARSA and KD and represents the first reported such case in the literature. Both cases progressed despite optimal medical therapy suggesting AAS with this anomalous anatomy needs a more aggressive operative approach. The involvement of KD in a patient with AAS appears to increase aortic disease progression and this anatomical variation should be considered another anatomical criterion that may place these patients at higher risk of complication. Progression during conservative management and waiting for the patient to be in the traditional safer 'sub-acute' time frame after presentation increased the eventual difficulty of the hybrid repair. A hybrid open-endovascular repair was utilized in all cases and is a safe and effective strategy for managing patients with ARSA and KD presenting with AAS. [ABSTRACT FROM AUTHOR]