The Treatment of Complex Extremity Wounds Using External Tissue Expansion: A Case Series.

SUMMARY: The goal of wound reconstruction is the approximation of soft tissue and re-establishment of an acceptable appearance with minimal risk of complications. For large wound closure in the extremities, skin graft and flap reconstruction are common treatments but are associated with a variety of complications. Comparatively, tissue expansion can provide the opportunity to reconstruct large wounds with native, durable, and sensate tissue without significant donor site morbidity. External tissue expansion is less invasive and avoids complications associated with internal expansion. The authors treated 11 patients with varying extremity wound types and sizes with an external tissue expansion device. Patient age ranged from 18 to 68 years with an average age of 43.7 years (SD, ± 13.1 years). Average wound surface area was approximately 235 cm 2 (SD, ± 135.3 cm 2 ). Devices were affixed and left for 7 to 11 days before closure of the wounds. Outcomes were assessed at 2 to 36 weeks postoperative follow-up. All wounds were fully closed after treatment without need for secondary reconstructive procedures. No patient experienced major complications. All patients demonstrated intact sensation within the area of reconstruction equivalent to surrounding tissues. External tissue expansion, an excellent treatment option in extremity reconstruction, is efficacious and associated with lower complication rates compared with internal tissue expansion, skin grafts, and flap reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Contactless Deformation Monitoring of Bridges with Spatio-Temporal Resolution: Profile Scanning and Microwave Interferometry.

Against the background of an aging infrastructure, the condition assessment process of existing bridges is becoming an ever more challenging task for structural engineers. Short-term measurements and structural monitoring are valuable tools that can lead to a more accurate assessment of the remaining service life of structures. In this context, contactless sensors have great potential, as a wide range of applications can already be covered with relatively little effort and without having to interrupt traffic. In particular, profile scanning and microwave interferometry, have become increasingly important in the research field of bridge measurement and monitoring in recent years. In contrast to other contactless displacement sensors, both technologies enable a spatially distributed detection of absolute structural displacements. In addition, their high sampling rate enables the detection of the dynamic structural behaviour. This paper analyses the two sensor types in detail and discusses their advantages and disadvantages for the deformation monitoring of bridges. It focuses on a conceptual comparison between the two technologies and then discusses the main challenges related to their application in real-world structures in operation, highlighting the respective limitations of both sensors. The findings are illustrated with measurement results at a railway bridge in operation.

Advancing Ground-Based Radar Processing for Bridge Infrastructure Monitoring.

In this study, we further develop the processing of ground-based interferometric radar measurements for the application of bridge monitoring. Applying ground-based radar in such complex setups or long measurement durations requires advanced processing steps to receive accurate measurements. These steps involve removing external influences from the measurement and evaluating the measurement uncertainty during processing. External influences include disturbances caused by objects moving through the signal, static clutter from additional scatterers, and changes in atmospheric properties. After removing these influences, the line-of-sight displacement vectors, measured by multiple ground-based radars, are decomposed into three-dimensional displacement components. The advanced processing steps are applied exemplarily on measurements with two sensors at a prestressed concrete bridge near Coburg (Germany). The external influences are successfully removed, and two components of the three-dimensional displacement vector are determined. A measurement uncertainty of less than 0.1 mm is achieved for the discussed application.

Insights into Peptoid Helix Folding Cooperativity from an Improved Backbone Potential.

Peptoids (N-substituted oligoglycines) are biomimetic polymers that can fold into a variety of unique structural scaffolds. Peptoid helices, which result from the incorporation of bulky chiral side chains, are a key peptoid structural motif whose formation has not yet been accurately modeled in molecular simulations. Here, we report that a simple modification of the backbone φ-angle potential in GAFF is able to produce well-folded cis-amide helices of (S)-N-(1-phenylethyl)glycine (Nspe), consistent with experiment. We validate our results against both QM calculations and NMR experiments. For this latter task, we make quantitative comparisons to sparse NOE data using the Bayesian Inference of Conformational Populations (BICePs) algorithm, a method we have recently developed for this purpose. We then performed extensive REMD simulations of Nspe oligomers as a function of chain length and temperature to probe the molecular forces driving cooperative helix formation. Analysis of simulation data by Lifson-Roig helix-coil theory show that the modified potential predicts much more cooperative folding for Nspe helices. Unlike peptides, per-residue entropy changes for helix nucleation and extension are mostly positive, suggesting that steric bulk provides the main driving force for folding. We expect these results to inform future work aimed at predicting and designing peptoid peptidomimetics and tertiary assemblies of peptoid helices.