Wireless and Battery-Free Sensor for Interstitial Fluid Pressure Monitoring.

Congestive heart failure (CHF) is a fatal disease with progressive severity and no cure; the heart's inability to adequately pump blood leads to fluid accumulation and frequent hospital readmissions after initial treatments. Therefore, it is imperative to continuously monitor CHF patients during its early stages to slow its progression and enable timely medical interventions for optimal treatment. An increase in interstitial fluid pressure (IFP) is indicative of acute CHF exacerbation, making IFP a viable biomarker for predicting upcoming CHF if continuously monitored. In this paper, we present an inductor-capacitor (LC) sensor for subcutaneous wireless and continuous IFP monitoring. The sensor is composed of inexpensive planar copper coils defined by a simple craft cutter, which serves as both the inductor and capacitor. Because of its sensing mechanism, the sensor does not require batteries and can wirelessly transmit pressure information. The sensor has a low-profile form factor for subcutaneous implantation and can communicate with a readout device through 4 layers of skin (12.7 mm thick in total). With a soft silicone rubber as the dielectric material between the copper coils, the sensor demonstrates an average sensitivity as high as -8.03 MHz/mmHg during in vitro simulations.

Enhanced Carrier Transport in Strongly Coupled, Epitaxially Fused CdSe Nanocrystal Solids.

Strongly coupled, epitaxially fused colloidal nanocrystal (NC) solids are promising solution-processable semiconductors to realize optoelectronic devices with high carrier mobilities. Here, we demonstrate sequential, solid-state cation exchange reactions to transform epitaxially connected PbSe NC thin films into Cu2Se nanostructured thin-film intermediates and then successfully to achieve zinc-blende, CdSe NC solids with wide epitaxial necking along {100} facets. Transient photoconductivity measurements probe carrier transport at nanometer length scales and show a photoconductance of 0.28(1) cm2 V-1 s-1, the highest among CdSe NC solids reported. Atomic-layer deposition of a thin Al2O3 layer infiltrates and protects the structure from fusing into a polycrystalline thin film during annealing and further improves the photoconductance to 1.71(5) cm2 V-1 s-1 and the diffusion length to 760 nm. We fabricate field-effect transistors to study carrier transport at micron length scales and realize high electron mobilities of 35(3) cm2 V-1 s-1 with on-off ratios of 106 after doping.

The study on the spatiotemporal changes in tradeoffs and synergies of ecosystem services and response to land use/land cover changes in the region around Taihu Lake.

Interactions among ecosystem services (ESs) involve tradeoffs and synergies. Quantitatively studying the trade-off and synergistic relationships between land use/land cover change (LULC) and ESs enables the precise identification of the quality status and driving factors of ESs within the region, which is crucial for rational resource allocation and environmental protection. In this study, the spatial and temporal change characteristics of the three ESs of carbon storage (CS), soil retention (SR) and habitat quality (HQ) are explored by using the InVEST model and GIS technology in the region around Taihu Lake, and the tradeoffs and synergies among the three are determined based on the difference comparison. The results indicate that: (1) The study area has a downward trajectory in CS and HQ from 1990 to 2020, while SR experiences some fluctuations. The spatial distribution of the three ESs exhibits high levels in the southwest and low levels in the northeast. (2) The most sensitive regions where tradeoffs and synergies are most pronounced occur primarily in the newly construction land regions and the southwestern mountainous and hilly areas. In newly construction land regions, there are often tradeoffs relationships observed between CS and SR, as well as between HQ and SR. Conversely, a predominantly negative synergy is mainly observed between CS and HQ. In the southwestern hilly terrain, due to changes in landscape patterns, HQ and SR exhibit higher levels of negative synergistic relationships. (3) LULC is a significant driver of spatial and temporal changes in ESs, as well as changes in tradeoffs and synergies in the study area, necessitating integrated research from economic, social and climate change perspectives.

Intra-beat biomarker for accurate continuous non-invasive blood pressure monitoring.

Accurate continuous non-invasive blood pressure (CNIBP) monitoring is the holy grail of digital medicine but remains elusive largely due to significant drifts in signal and motion artifacts that necessitate frequent device recalibration. To address these challenges, we developed a unique approach by creating a novel intra-beat biomarker (Diastolic Transit Time, DTT) to achieve highly accurate blood pressure (BP) estimations. We demonstrated our approach's superior performance, compared to other common signal processing techniques, in eliminating stochastic baseline wander, while maintaining signal integrity and measurement accuracy, even during significant hemodynamic changes. We applied this new algorithm to BP data collected using non-invasive sensors from a diverse cohort of high acuity patients and demonstrated that we could achieve close agreement with the gold standard invasive arterial line BP measurements, for up to 20 min without recalibration. We established our approach's generalizability by successfully applying it to pulse waveforms obtained from various sensors, including photoplethysmography and capacitive-based pressure sensors. Our algorithm also maintained signal integrity, enabling reliable assessments of BP variability. Moreover, our algorithm demonstrated tolerance to both low- and high-frequency motion artifacts during abrupt hand movements and prolonged periods of walking. Thus, our approach shows promise in constituting a necessary advance and can be applied to a wide range of wearable sensors for CNIBP monitoring in the ambulatory and inpatient settings.