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Tissue failure at suture lines contributes to complications and readmissions following complex surgeries in distensible organs such as those performed in the lower urinary tract. Excess tension at points of tissue approximation can contribute to abnormal wound healing, urine leaks, infections, and fistula development. A flexible biodegradable adhesive patch that adheres to dynamic tissue and prevents non-targeted adhesion to adjacent tissue is needed to provide support at suture sites throughout the wound healing process. Herein, we have developed a ready-to-use bilayer adhesive patch (BLAP) to reinforce suture lines for application to expandable and dynamic fluid-filled tissues such as the bladder. The external non-adhesive layer of BLAP comprises a bioabsorbable poly(glycerol sebacate) (PGS) elastomer, preventing undesired adhesion to the adjunct tissues. The internal tissue binding layer is composed of PGS modified with L-dopamine (L-DOPA) to allow immediate adhesion to the wet surface of the target tissue. Physical and mechanical properties of the patches were tuned by varying glycerol to sebacate ratios, L-DOPA contents, and curing time to achieve compliance that approximates that of bladder tissue. The candidate PG2S and PG2SD0.018 biomaterials of the designed BLAP demonstrated Young's moduli of 49.4 kPa and 61.5 kPa and stretchability between 174.7% and 223.7%, respectively. BLAP adhered tightly to a porcine bladder repaired cystotomy ex vivo, reinforcing the sutured line and increasing bladder burst pressure more than stand-alone surgical sutures or a commercial bioadhesive glue, Tisseel®. These features, combined with >90% cytocompatibility and biodegradability, render BLAP a promising elastic bioadhesive patch to reinforce suture lines in the bladder. Beyond the urinary tract, BLAP has the potential to be mechanically tuned for a variety of other non-planar, dynamic tissues. 

Geomagnetic Ultra Low Frequency (ULF) are terrestrial manifestations of the propagation of very low frequency magnetic fluid waves in the magnetosphere, and it is critical to develop near real-time space weather products to monitor these geomagnetic disturbances. A wavelet-based index is described in this paper and applied to study geomagnetic ULF pulsations observed in Antarctica and their magnetically conjugate locations in West Greenland. Results showed that (1) the index is effective for identification of pulsation events in the Pc4–Pc5 frequency range, including transient events, and measures important characteristics of ULF pulsations in both the temporal and frequency domains. (2) Comparison between conjugate locations reveals the similarities and differences between ULF pulsations in northern and southern hemispheres during solstice conditions, when the largest asymmetries are expected. Results also showed that the geomagnetic pulsations at conjugate locations respond differently according to the Interplanetary Magnetic Field condition, magnetic field topology, magnetic latitude of the observation, and other conditions. The actual magnetospheric and ionospheric configurations and driving conditions in the case need to be further studied. 

Abstract Accurate and timely inland waterbody extent and location data are foundational information to support a variety of hydrological applications and water resources management. Recently, the Cyclone Global Navigation Satellite System (CYGNSS) has emerged as a promising tool for delineating inland water due to distinct surface reflectivity characteristics over dry versus wet land which are observable by CYGNSS’s eight microsatellites with passive bistatic radars that acquire reflected L-band signals from the Global Positioning System (GPS) (i.e., signals of opportunity). This study conducts a baseline 1-km comparison of water masks for the contiguous United States between latitudes of 24°N-37°N for 2019 using three Earth observation systems: CYGNSS (i.e., our baseline water mask data), the Moderate Resolution Imaging Spectroradiometer (MODIS) (i.e., land water mask data), and the Landsat Global Surface Water product (i.e., Pekel data). Spatial performance of the 1-km comparison water mask was assessed using confusion matrix statistics and optical high-resolution commercial satellite imagery. When a mosaic of binary thresholds for 8 sub-basins for CYGNSS data were employed, confusion matrix statistics were improved such as up to a 34% increase in F1-score. Further, a performance metric of ratio of inland water to catchment area showed that inland water area estimates from CYGNSS, MODIS, and Landsat were within 2.3% of each other regardless of the sub-basin observed. Overall, this study provides valuable insight into the spatial similarities and discrepancies of inland water masks derived from optical (visible) versus radar (Global Navigation Satellite System Reflectometry, GNSS-R) based satellite Earth observations. 

Transition metal dichalcogenide (TMD) twisted homobilayers have been established as an ideal platform for studying strong correlation phenomena, as exemplified by the recent discovery of fractional Chern insulator (FCI) states in twisted MoTe21–4 and Chern insulators (CI)5 and unconventional superconductivity6,7 in twisted WSe2. In these systems, nontrivial topology in the strongly layer-hybridized regime can arise from a spatial patterning of interlayer tunneling amplitudes and layer-dependent potentials that yields a lattice of layer skyrmions. Here we report the direct observation of skyrmion textures in the layer degree of freedom of Rhombohedralstacked (R-stacked) twisted WSe2 homobilayers. This observation is based on scanning tunneling spectroscopy that separately resolves the G-valley and K-valley moiré electronic states. We show that G-valley states are subjected to a moiré potential with an amplitude of ~ 120 meV. At ~150 meV above the G-valley, the K-valley states are subjected to a weaker moiré potential of ~30 meV. Most significantly, we reveal opposite layer polarization of the K-valley at the MX and XM sites within the moiré unit cell, confirming the theoretically predicted skyrmion layer-texture. The dI/dV mappings allow the parameters that enter the continuum model for the description of moiré bands in twisted TMD bilayers to be determined experimentally, further establishing a direct correlation between the shape of LDOS profile in real space and topology of topmost moiré band. 

Charge transfer is a fundamental interface process that can be harnessed for light detection, photovoltaics, and photosynthesis. Recently, charge transfer was exploited in nanophotonics to alter plasmon polaritons by involving additional non-polaritonic materials to activate the charge transfer. Yet, direct charge transfer between polaritonic materials has not been demonstrated. We report the direct charge transfer in pure polaritonic van der Waals (vdW) heterostructures of α-MoO3/graphene. We extracted the Fermi energy of 0.6 eV for graphene by infrared nano-imaging of charge transfer hyperbolic polaritons in the vdW heterostructure. This unusually high Fermi energy is attributed to the charge transfer between graphene and α-MoO3. Moreover, we have observed charge transfer hyperbolic polaritons in multiple energy–momentum dispersion branches with a wavelength elongation of up to 150%. With the support from the density functional theory calculation, we find that the charge transfer between graphene and α-MoO3, absent in mechanically assembled vdW heterostructures, is attributed to the relatively pristine heterointerface preserved in the epitaxially grown vdW heterostructure. The direct charge transfer and charge transfer hyperbolic polaritons demonstrated in our work hold great promise for developing nano-optical circuits, computational devices, communication systems, and light and energy manipulation devices.