The fluvial architecture of buried floodplain sediments of the Weiße Elster River (Germany) revealed by a novel method combination of drill cores with two‐dimensional and spatially resolved geophysical measurements

The complex and non-linear fluvial river dynamics are characterized by repeated periods of fluvial erosion and re-deposition in different parts of the floodplain. Understanding the fluvial architecture (i.e. the three-dimensional arrangement and genetic interconnectedness of different sediment types) is therefore fundamental to obtain well-based information about controlling factors. However, investigating the fluvial architecture in buried floodplain deposits without natural exposures is challenging. We studied the fluvial architecture of the middle Weiße Elster floodplain in Central Germany, an extraordinary long-standing archive of Holocene flooding and landscape changes in sensitive loess-covered Central European landscapes. We applied a novel systematic approach by coupling two-dimensional transects of electrical resistivity tomography (ERT) measurements and closely spaced core drillings with spatially resolved measurements of electromagnetic induction (EMI) of larger floodplain areas at three study sites. This allowed for (i) time and cost-efficient core drillings based on preceding ERT measurements and (ii) spatially scaling up the main elements of the fluvial architecture, such as the distribution of thick silt-clay overbank deposits and paleochannel patterns from the floodplain transects to larger surrounding areas. We found that fine-grained sand and silt-clay overbank deposits overlying basal gravels were deposited during several periods of intensive flooding. Those were separated from each other by periods of reduced flooding, allowing soil formation. However, the overbank deposits were severely laterally eroded before and during each sedimentation period. This was probably linked with pronounced meandering or even braiding of the river. Our preliminary chronological classification suggests that first fine-grained sedimentation must have occurred during the Early to Middle Holocene, and the last phase of lateral erosion and sedimentation during the Little Ice Age. Our study demonstrates the high archive potential of the buried fluvial sediments of the middle Weiße Elster floodplain and provides a promising time and cost-effective approach for future studies of buried floodplain sediments

Structure of the elusive hydrido(methylcyclopentadienyl)dicarbonylmanganate(I) anion, [(η⁵-C₅H₄Me)Mn(CO)₂H]-, as determined by single-crystal X-ray diffraction

The structure of [K(18-crown-6)][(η5-C5H4Me)Mn(CO)2H] has been determined by single-crystal X-ray diffraction, and the anion is found to adopt a three-legged piano-stool geometry. Its structure is compared with those of related bridging hydride and σ-bond complexes

Intraoperative Cytology for Video-Assisted Thoracic Surgery : A Quality Improvement Analysis

Background: Frozen section is a standard of care procedure during thoracic surgery when an immediate diagnosis is needed. An alternative procedure is intraoperative cytology. Video-assisted thoracic surgery is currently widely used for thoracic surgical procedures. The aim of this study was to assess intraoperative cytology together with frozen section for accuracy, turnaround time, and total response time during video-assisted thoracic surgery. Methods: We included patients having video-assisted thoracic surgery between August 2018 and February 2019 at our institution. A cytopathologist and a surgical pathologist independently performed intraoperative cytology and frozen sections, respectively. Final histologic diagnosis was the reference standard. Intraoperative cytology, frozen section turnaround, and total response times were analyzed. Results: A total of 52 specimens from 27 patients were included. The intraoperative cytology correlated with final histology in 98% of cases. Frozen section correlated with final histology in 100% of cases. Intraoperative cytology turnaround and total response times were equal (mean, 4.35 minutes; range, 2-15 minutes). Mean frozen section turnaround and response times were 26.2 minutes (range, 9-61 minutes) and 36.7 minutes (range, 16-90 minutes), respectively. We found a statistically significant difference between intraoperative cytology and frozen section turnaround time and total response times (P < .001). Conclusions: This study highlights that intraoperative cytology could be as accurate as frozen section and considerably faster during video-assisted thoracic surgery (P < .001). Total response time could potentially be used as a quality metric for video-assisted thoracic surgery