Pressure Sensor Research Articles

Performance and Robustness of Physiological Controllers With Integrated Pressure Sensors on Inflow Cannula.

The control of left ventricular assist devices (LVADs) requires sensors and/or estimators to account for the physiological state of the patient and apply advanced controllers. Sensor characteristics are a challenge when using implantable pressure sensors because they influence the quality of physiological control and the robustness of the controlled system. The objective of this work is to investigate the performance and robustness of LVAD controllers that operate based on LVAD integrated pressure sensors. Four pressure-based LVAD controllers are tested with a HeartMate 3 that has an integrated pressure sensor. Controller sensitivity as well as robustness to sensor drift and noise are evaluated based on controller response to large changes in preload and afterload. A fail-safe strategy for sensor failure used also to investigate the reliable operation of the LVAD in realistic conditions. All tested controllers are sensitive to drifting pressure signals, which can lead to unstable behavior. The results show that two controllers are robust to noise. The other two controllers show high deviation and oscillation in cardiac output even for small noise. Additionally, a noticeable difference of the controller's response between simulated and measured pressure input was observed, indicating the need for a robust controller design. Reliable operation even in the event of a sensor failure was achieved on the basis of a fail-safe control system.

AgNPs/CNTs modified nonwoven fabric for PET-based flexible interdigitated electrodes in pressure sensor applications

Intelligent wearable sensing technology plays a pivotal role in the era of the Internet of Things and artificial intelligence, especially for human–machine interaction, physiological monitoring, and intelligent robotics. However, achieving a wide sensing range, high sensitivity, and ultra-long durability in pressure sensors while maintaining a simple and cost-effective fabrication remains challenging. This study presents a novel pressure sensor using silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) modified nonwoven fabric for polyethylene terephthalate (PET) flexible interdigitated electrodes (IDEs). A low-cost spray-coating method was employed to deposit AgNPs/CNTs onto nonwoven fabric as the sensing layer, which was then combined with PET-based IDEs and encapsulated using polyimide (PI) film. The resulting piezoresistive sensor exhibits an extensive sensing range up to 90 kPa, high sensitivity up to 20 kPa−1 within 0–2 kPa, rapid response/recovery times (48 ms/44 ms), and outstanding repeatability over 6000 cycles. It can be assembled into an electronic skin tactile sensor array for mapping tactile size and orientation, and integrated into clothing for real-time monitoring of physiological signals like pulse, heartbeat, and grasp force. This work proposes a novel approach for developing wearable, highly sensitive, and wide-ranging pressure sensors, showing potential for multifunctional applications in next-generation artificial electronic skin, personal health monitoring, intelligent robotics, and human–machine interaction

Investigating the Potential of Cr3+-Doped Pyroxene for Highly Sensitive Optical Pressure Sensing.

Luminescent manometry has gained significant popularity in recent years due to its capability to provide in situ pressure measurements in a remote manner. Therefore, there is a growing need to identify phosphors with pressure-dependent spectroscopic properties that can be utilized to develop highly sensitive pressure sensors operating over a wide pressure range. Hence, we present a novel temperature-invariant luminescent manometer based on Cr3+ ion emission in pyroxene Ca0.8Sr0.2MgSi2O6:Cr3+. We utilized two readout modes, including an innovative luminescent pressure sensing ratiometric approach based on the broad emission band associated with the 4T2g → 4A2g electronic transition of Cr3+ ions. This approach provided an exceptionally high sensitivity of SR = 50.7 ± 0.5% GPa-1 and ensured temperature-independent pressure measurements, thus offering highly reliable readouts. Furthermore, the proposed readout mode, which leverages changes in luminescence kinetics, demonstrated high sensitivity at high pressure at around 5 GPa (SR ∼ 8 ± 0.2% GPa-1) surpassing the performance of luminescence kinetics-based manometers reported to date. Consequently, Ca0.8Sr0.2MgSi2O6:Cr3+ emerges as a highly promising phosphor with significant application potential for pressure sensing across a broad pressure range.

Optimal design parameter estimation and analytical investigation of MEMS quadruple touch mode capacitive pressure sensor

Purpose Touch mode capacitive pressure sensors (TMCPS) offer superior sensitivity and linearity in comparison to normal mode CPS and have therefore seen substantial improvements in modeling and construction. This study aims to develop a sensor that is highly robust, with near-linear output characteristics, increased sensitivity and superior overload protection, making it an ideal choice for deployment in harsh industrial environments. Design/methodology/approach The proposed sensor design uses a substrate with a multi-step notch, introducing a new quadruple TMCPS and uses a small deflection model for mathematical analysis. Addition of a multi-step notch to traditional touch mode capacitive sensors results in quadruple touch regions which further enhances its operational range performance. Findings The simulation of diaphragm deflection in response to pressure is carried out by using COMSOL Multiphysics, whereas MATLAB is used for analytical simulations pertaining to variations in capacitance and capacitive sensitivity. Comparing with earlier models, there is a noticeable enhancement in capacitance, experiencing a fivefold increase. The achieved value stands at 50.1 pF, reflecting improved sensitivity for applied pressure ranging from 0 to 2 MPa. Originality/value In existing literature to improve the performance of the single TMCPS, a double-sided TMCPS has been developed. To enhance sensor performance, a substrate with a multi-step notch is proposed. The notch creates four touch regions with varying gap depths, resulting in increased capacitance and capacitive sensitivity.

Measurement inaccuracy reported via the Manufacturer and User Facility Device Experience database for an implantable pulmonary artery pressure sensor: recalibration direction and magnitude results

Abstract Introduction Remote monitoring using an implantable pulmonary artery pressure (PAP) sensor (CardioMEMS HF system) in patients with heart failure (HF) has been consistently shown to reduce HF hospitalizations [1]. The success of this approach relies on the accurate measurement of diastolic PAP (dPAP) over time to allow early interventions such as diuretic intensification [2]. However, it remains unclear how the measurement accuracy changes over time after the initial calibration at the time of device implantation. Purpose This study aims to identify measurement inaccuracy events and to quantify the magnitude and direction of required device recalibration for CardioMEMS devices as reported in a large-scale regulatory device database. Methods We used the publicly accessible Manufacturer and User Facility Device Experience (MAUDE) data maintained by the US Food and Drug Administration (FDA). The summary search was performed for the CardioMEMS pulmonary artery pressure sensor for the entire product life cycle from January 2009 to February 2024 [3,4]. The entries related to the measurement accuracy under ‘Device Problems’ categories were obtained. Tested accuracy was reported to have been within ±10mmHg of a reference pressure measurement throughout simulated use for 10 years [5]. Normal range for dPAP is ~8mmHg to 15mmHg [6]. Results A total of 2656 entries were obtained. Following categories were identified for the reported entries: device sensing problem (N=999, 38%); incorrect measurement (N=1349, 52%); incorrect measurement, inappropriate waveform (N=279, 11%), and incorrect, inadequate, or imprecise results or readings (N=29, 1%). After excluding 56 entries for missing information, 2600 entries were included for the analysis. A total of 1676 (64%) entries reported the need for recalibration of the CardioMEMS device. A mean PAP difference (defined as the difference of the mean PAP reference value measured at the time of recalibration minus the CardioMEMS reading obtained during the reference measurement) is shown in Figure 1. Compared to the reference pressure values at the time of recalibration, 488 (29%) of CardioMEMS readings were higher and 1188 (71%) were lower. The absolute recalibration pressure difference was 14.5 ± 9.3 mmHg (mean ± standard deviation, range 0.02-59.3 mmHg). The recalibration by more than 10 mmHg was reported in 1040 (40%) entries. Conclusions Suspected measurement inaccuracy with CardioMEMS device is not uncommon and often necessitate recalibration. Almost one-half (40%) of the recalibrations required more than 10 mmHg correction. These results should inform clinicians to consider recalibration along the course of CardioMEMS monitoring if there is discordance between clinical assessment and the values from the device.Figure 1.Figure 2

Vacuum Filtration-Coated Silver Electrodes Coupled with Stacked Conductive Multi-Walled Carbon Nanotubes/Mulberry Paper Sensing Layers for a Highly Sensitive and Wide-Range Flexible Pressure Sensor

Flexible pressure sensors based on paper have attracted considerable attention owing to their good performance, low cost, and environmental friendliness. However, effectively expanding the detection range of paper-based sensors with high sensitivities is still a challenge. Herein, we present a paper-based resistive pressure sensor with a sandwich structure consisting of two electrodes and three sensing layers. The silver nanowires were dispersed deposited on a filter paper substrate using the vacuum filtration coating method to prepare the electrode. And the sensing layer was fabricated by coating carbon nanotubes onto a mulberry paper substrate. Waterborne polyurethane was introduced in the process of preparing the sensing layers to enhance the strength of the interface between the carbon nanotubes and the mulberry paper substrate. Therefore, the designed sensor exhibits a good sensing performance by virtue of the rational structure design and proper material selection. Specifically, the rough surfaces of the sensing layers, porous conductive network of silver nanowires on the electrodes, and the multilayer stacked structure of the sensor collaboratively increase the change in the surface contact area under a pressure load, which improves the sensitivity and extends the sensing range simultaneously. Consequently, the designed sensor exhibits a high sensitivity (up to 6.26 kPa−1), wide measurement range (1000 kPa), low detection limit (~1 Pa), and excellent stability (1000 cycles). All these advantages guarantee that the sensor has potential for applications in smart wearable devices and the Internet of Things.

Filiform Papillae‐Inspired Wearable Pressure Sensor with High Sensitivity and Wide Detection Range

AbstractFlexible pressure sensor (FPS) has promising applications in fields like health monitoring and human–machine interactions. The achieving of both high sensitivity and wide detection range in FPS remains highly challenging. Here, inspired by the filiform papillae on cat tongue, a FPS (noted as FPSp) with a sensitivity up to 504.5 kPa−1, a detection range from 30 Pa to 350 kPa, a fast response time of 83 ms, and a high stability over 8000 cycles is developed. The papilla‐like structure continuously shifts the location of stress concentration under increasing pressure, which avoids the accumulation of stress at papillae tips, resulting in a high sensitivity and wide detection range. Moreover, FPSp demonstrates capabilities in monitoring human physiological signals and movement status and can serve as the human‐machine interaction interface. The work not only presents a promising wearable pressure sensor but also establishes a design strategy for high‐performance wearable bioelectronics.

Coronary flow characteristics in cases with discordance between coronary flow reserve and the index of microvascular resistance in the assessment of coronary microvascular dysfunction

Abstract Background/Introduction Coronary flow reserve (CFR) and the index of microvascular resistance (IMR) are commonly used for the diagnosis of coronary microvascular dysfunction, but the two indices can reveal discordance. Purpose The aim of this study was to investigate the mechanisms of the discordance between CFR and IMR. Methods Haemodynamic data from patients who underwent invasive coronary functional assessment using a guidewire equipped with pressure and temperature sensors was analysed. We performed vessel-based analysis, and classified vessels with reference to the criteria of IMR ≥25 and CFR <2.0 as pathological into four groups: normal IMR/normal CFR (Group 1: G1), abnormal IMR/normal CFR (Group 2: G2), normal IMR/abnormal CFR (Group 3: G3), and abnormal IMR/abnormal CFR (Group 4: G4). Results Of 249 vessels form 176 patients, 82 (33%) were classified into G1, 28 (11%) into G2, 94 (38%) into G3, and 45 (18%) into G4. Median and interquartile ranges of IMR of the four groups were 14.3 [10.7–18.9], 34.2 [29.8–45.1], 16.9 [12.7–19.7], and 30.7 [28.4–43.5] (P <0.001), respectively, and those of CFR were 3.21 [2.48–4.29], 2.73 [2.34–3.03], 1.27 [1.06–1.55], and 1.28 [1.07–1.67] (P <0.001), respectively (Figure). In G2, hyperemic flow velocity was as low as G4 (1.97 [1.47–2.29] vs. 1.95 [1.41–2.50] sec-1, P=1.00), and the baseline flow velocity was lower than G4 (0.71 [0.49–0.85] vs. 1.44 [0.93–1.96] sec-1, P <0.001), leading to apparently normal CFR despite the diminished hyperemic flow. In G3, the hyperemic (3.60 [2.77–4.73] vs. 1.95 [1.41–2.50] sec-1, P <0.001) and the baseline flow velocity (2.85 [2.19–3.92] vs. 1.44 [0.93–1.96] sec-1, P <0.001) were higher than G4, leading to apparently decreased CFR despite the maintained hyperemic flow. Conclusion(s) The discordance between IMR and CFR can be explained by decreased coronary flow in abnormal IMR/normal CFR, and by increased baseline coronary flow in normal IMR/abnormal CFR.

Suture anchor and transtibial pullout refixation of the posterior medial meniscus root tears restore tibiofemoral contact pressure and area to intact meniscus levels.

To compare the load distributed to the medial tibial articular cartilage after refixation of posterior medial meniscus root tears between the suture anchor and transtibial pullout techniques in posterior medial meniscus root tears. Twelve Thiel's embalmed human cadaveric knees are used and divided into three groups (four knees in each group): (1) intact meniscus (IM), (2) fixation with suture anchor technique (SA) and (3) fixation with transtibial pullout technique (TP). Each group applies an axial compression load up to 1500 N by Instron E 10000 at two knee flexion angles (0° and 60°). A Tekscan 4000 pressure sensor is used to record the contact pressure and the contact area for each testing condition. The contact pressure and the contact area between the three conditions are not significantly different at 0° and 60° knee flexion angles. The peak contact pressure and contact area are 3734.8 ± 2642.2 kPa, 288.2 ± 115.0 mm2, 4510 ± 2930.5 kPa, 204.4 ± 36.8 mm2 and 5328.8 ± 2607.7 kPa, 219.2 ± 84.7 mm2 in IM, SA and TP, respectively. Both suture anchor and transtibial pullout refixation of PMMRT can restore contact pressure and contact area similar to the intact meniscus. This finding suggests that either technique can be reliably used in clinical practice to preserve joint function and potentially reduce the risk of osteoarthritis progression following posterior medial meniscus root tear repairs. Level III.

Feasibility of novel robot-assisted, remotely-performed echocardiographic examination

Abstract Background Access to echocardiography services outside metropolitan areas is persistently limited. We sought to determine the feasibility and efficiency of performing remotely-controlled, semi-automated robot-assisted echocardiographic examinations (robot-assisted echo) by cardiac sonographers as a potential avenue to provide standard echocardiographic specialist services to remote and rural areas as well as permit expedited diagnoses enabling earlier management of disease. Methods Two accredited cardiac sonographers (Cardiac Investigations Unit) undertook 6 hours virtual training, and 10 hours hands-on robot-assisted echo simulation training; using a novel, semi-automated robotic arm system to remotely manipulate an ultrasound probe to acquire echocardiographic images. Sonographers then performed remotely-performed robot-assisted echo examinations on staff volunteers, and consenting inpatients in whom echocardiography was clinically indicated. Cameras, probe pressure sensors and an ultrasound platform remote console were utilised to support remote operation. Traditional echocardiography (manipulation of probe by hand) was also performed as a reference. Feasibility to obtain a comprehensive robot-assisted echo was compared to traditional echocardiography. Sonographer learning curve and efficiency (image acquisition time and offline measurement time) was also investigated. Results Total cohort was n=78 (age 51±15yrs; 57% male) with 63% patients. All participants had robot-assisted echo and traditional echocardiograms performed within 72hrs. Average feasibility (%) of robot-assisted echo as (a) 11 averaged assessments and (b) 38 averaged measures was 92±9 (a) and 86±11 (b), compared to (a) 99±1 and (b) 97±7 by traditional examination (all respectively). Sonographer learning curve was identified via 1:1 block subcohort analysis, with averaged assessment feasibility (n=33:31) being 86±19 (first block) to 98±3 (last block) and averaged measurement feasibility (n=32:31) being 77±11 (first block) to 92±7 (last block), all respectively. In the staff participant cohort (n=31), average image acquisition efficiency in robot-assisted echo was poorer than that of traditional examination (47+9 minutes compared to 19+2 minutes; p<0.0001), respectively. Average efficiency of offline measurement time was 13+7 minutes by robot-assisted echo; comparable (p=0.33) to traditional examination at 12+6 minutes. There was no learning curve effect on image acquisition efficiency; 42+10 vs 51+7 minutes (1:1; n=16:15; p=0.007). Conclusion Remotely-performed, robot-assisted echo using a commercially-available ultrasound platform performed by briefly-trained, cardiac sonographers is feasible, with reasonable efficiency even though less efficient in image acquisition compared to traditional echocardiograms. Further investigation of performance as a remote service is warranted in larger, clinically-indicated populations.

Heart failure hospitalization reduction and long-term safety with remote pulmonary artery pressure monitoring: results of the CardioMEMS HF System OUS Post-Market Study

Abstract Background Heart failure (HF) is increasing in prevalence and is responsible for frequent hospitalization and readmissions, despite current guideline recommended therapies. Hemodynamic guided HF management using frequently remotely obtained pulmonary artery (PA) pressure information using a permanently implanted PA sensor (CardioMEMSTM HF System, Abbott) consistently reduced HF hospitalizations (HFH) in multiple healthcare settings. The safety and efficacy of the CardioMEMS HF System has been shown previously in several clinical studies, which reported significant reductions in HFH compared to a control (CHAMPION: 33%, 18M; GUIDE-HF: 28%, 1 yr; and MONITOR-HF: 44%, 1 yr) and longitudinally (MEMS-HF: 62%, 1 yr; and CardioMEMS US PAS: 57%, 1 yr) across varying health systems. Purpose The CardioMEMS HF System OUS Post-Market Study (COAST) aimed to evaluate the safety and effectiveness of hemodynamic guided HF management in patients with NYHA Class III HF in varying health systems across Europe and Australia. Methods COAST is a prospective, multi-centre, open-label clinical trial that consented 321 patients at 38 European and Australian centres. The primary endpoint is a combination of safety (freedom from DSRCs and freedom from pressure sensor failure at 2 years after implant) and efficacy endpoints (annualized HFH rate at 1-year vs the HFH rate in the year prior to enrolment). In this analysis we report these primary results of the study. Results Out of 321 consented patients, 17 subjects were withdrawn before implant, while the PA sensor was implanted successfully in 299 out of 304 patients who underwent the procedure (98.3% success rate). Seventy-three percent (73%) of the patients were male, the mean age was 68.4±11.7 years with ischemic cardiomyopathy in 45.4%. At baseline, all patients had NYHA Class III symptoms and an average EQ-5D-5L VAS score of 60.0±21.6. After 2 years follow-up there was 100% freedom from DSRCs and 99.7% freedom from pressure sensor failure. The annualized HFH rate after 1 year decreased by 69%, from 1.586 (pre-implant) to 0.488 (post-implant) (p<0.0001). The patient’s quality of life (EQ-5D-5L VAS) increased 8.1 units (68.2 ± 20.1, p=0.0008). Conclusion The COAST Study demonstrated that hemodynamic-guided remote HF management using PA pressure information is both safe and effective, with consistent implant safety and low risk for long-term sensor failure. At 1 year post implant, HFH were significantly reduced and quality of life improved. These results are also consistent with long-term clinical follow-up (2 yr) in other geographies with no late-stage adverse events or adverse events from sensor implant, demonstrating the generalizability of this type of hemodynamic-guided HF management.

Initial results of the READY registry: comparison of visual and physiological lesion characterization and the effect of hydrostatic pressure correction

Abstract We aimed to compare resting Pd/Pa, FFR, and distal RFR values with and without hydrostatic pressure correction. Our main goal was to assess the influence of this correction on cut-off value-based decision-making for each physiological parameter. Data from patients enrolled in two centers of the READY registry (NCT04857762) were analyzed. Center 1 employed catheter and pressure sensor height differences defined from lateral angiographic projection for hydrostatic pressure correction, while Center 2 utilized average pressure differentials from published data. In Center 1, the height difference underlying the hydrostatic pressure correction did not differ significantly from the average values published in previous publication (-5.22±1.1cm for LAD, 2.44±1.1cm for CX, and 1.63±2.8cm for RCA). Consequently, FFR and distal RFR values corrected with average pressure differentials rarely yielded different cut-off-based characterizations compared to individually measured corrections (2.4%). A total of 42 measurements were evaluated in Center 1 (33 patients) and 40 measurements in Center 2 (40 patients). Stenoses were characterized using resting Pd/Pa (0.91 ± 0.05), FFR (0.80 ± 0.08), distal RFR (0.86 ± 0.09) and ΔRFR (0.07 ± 0.07) values. Regarding all the investigated vessels, statistically significant differences were observed in FFR (0.80 ± 0.08 vs 0.81 ± 0.08; p < 0.001), distal RFR (0.86 ± 0.09 vs 0.87 ± 0.09; p < 0.001), and ΔRFR (0.053 ± 0.04 vs 0.047 ± 0.04; p = 0.014) before and after correction. These changes after hydrostatic correction were driven dominantly by the LAD measurements being LAD stenoses constituted the majority of the cases (73.2%). Overall (n=82), hydrostatic pressure correction modified cut-off-based categorization in 24 (29.3%) cases for Pd/Pa, and 19 (23.2%) cases for both distal RFR and FFR measurements. Notably, ΔRFR assessment also changed in 22.2% of cases after correction. Among LAD stenoses (n=60), hydrostatic pressure correction altered cut-off-based characterization in 22 (36.7%), 19 (31.7%), and 17 (28.3%) cases of resting Pd/Pa, distal RFR, and FFR measurements, respectively. Hydrostatic pressure correction offers the potential to enhance the accuracy of intracoronary physiological measurements, especially for LAD stenoses. Our data suggest that the published average pressure differences of each coronary segment can be used for correction.Lateral view and delta RFRIndividual vs Average LAd correction

Ultralow-pressure-driven polarization switching in ferroelectric membranes

Van der Waals integration of freestanding perovskite-oxide membranes with two-dimensional semiconductors has emerged as a promising strategy for developing high-performance electronics, such as field-effect transistors. In these innovative field-effect transistors, the oxide membranes have primarily functioned as dielectric layers, yet their great potential for structural tunability remains largely untapped. Free of epitaxial constraints by the substrate, these freestanding membranes exhibit remarkable structural tunability, providing a unique material system to achieve huge strain gradients and pronounced flexoelectric effects. Here, by harnessing the excellent structural tunability of PbTiO3 membranes and modulating the underlying substrate’s elasticity, we demonstrate the tip-pressure-induced polarization switching with an ultralow pressure (down to 0.06 GPa). Moreover, as an application demonstration, we develop a prototype non-volatile ferroelectric field-effect transistor integrated on silicon that can be operated mechanically and electrically. Our findings underscore the great potential of oxide membranes for utilization in advanced non-volatile electronics and highly sensitive pressure sensors.

Single center experience of internal jugular vein as alternative access for implantation of a wireless pulmonary artery pressure sensor

Abstract This single-center study delves into the novel use of the internal jugular vein (IJ) as an alternative access pathway for the implantation of the CardioMEMS device, a wireless pulmonary artery pressure sensor. This approach is compared to the conventional femoral vein access in terms of procedural times, contrast volume, and patient outcomes. The study spans five years, from 2018 to 2023, evaluating the efficacy and safety of IJ access for CardioMEMS implantation. The analysis revealed a tendency towards shorter procedural times and reduced contrast volume with IJ access, although statistical significance was not reached due to the small sample size. Notably, IJ access provided a quicker needle-to-door time, suggesting benefits such as improved patient throughput and potentially shorter hospital stays, which are pivotal in a healthcare landscape that prioritizes efficiency and cost-effectiveness. In conclusion, this investigation offers initial evidence that IJ vein access is a feasible and potentially superior alternative for CardioMEMS device implantation. While the findings are preliminary due to the study's limited scale, they pave the way for future larger-scale, multicenter studies. Such research could confirm the benefits of IJ access and possibly influence clinical practices, enhancing the management of heart failure patients.

RGO/CTAB/CMF Flexible Pressure Sensor Based on Honeycomb Structure for Human Posture Signal Acquisition

rGO/CTAB/CMF Flexible Pressure Sensor Based on Honeycomb Structure for Human Posture Signal Acquisition

Effects of sodium-glucose cotransporter 2 inhibitors on pulmonary hemodynamics in chronic heart failure patients with a pulmonary artery pressure sensor

Abstract Background Approximately 50% of patients with chronic heart failure (HF), either with preserved or reduced left ventricular ejection fraction (LVEF), have secondary pulmonary hypertension, which results in poorer prognosis. In previous studies, sodium-glucose cotransporter 2 inhibitors (SGLT2i) have shown a reduction in cardiovascular death, HF hospitalization and pulmonary artery pressure (PAP) in patients with HF, regardless of LVEF, but exact mechanisms remain unclear. Purpose The main objective of this study is to analyse effects of SGLT2i on PAP in patients with chronic HF followed by a PAP sensor (CardioMEMS HF system). The secondary objective is to analyse effects in subgroups of LVEF. Methods We included chronic HF patients (regardless of LVEF) with previously implanted a PAP sensor, from July 2019 to February 2023. SGLT2i had been added in fourth position in patients with reduced LVEF, since they were previously on optimal HF treatment as chronic patients. Changes in PAP, renal function and N-terminal pro B-type natriuretic peptide (NTproBNP) were compared between two periods of time: "30 days before" and "30 days after" SGLT2i initiation. Patients were then classified in two groups: group 1 (LVEF ≤40%) and group 2 (LVEF >40%) and repeated same analyses. Results Overall, 61 patients were screened, and 17 finally were included, mean age 71.7 ± 9.6 years, 64.7% were men, mean LVEF was 49.4 ± 17.5%, 23.5% had ischaemic aetiology and 64.7% were in NYHA class III (Table 1). There were more men in group 1 than in group 2 (p=0.043), without other differences in basal characteristics between groups (Table 1). Dapagliflozin (10mg daily) was initiated in 14 patients (82.4%), 5 from group 1 and 9 from group 2 (p=1.000), and empagliflozin (10mg daily) in 3 patients (17.6%), 1 from group 1 and 2 from group 2 (p=1.000). Before SGLT2i, mean diastolic PAP (dPAP) was 17.3 ± 5.6 mmHg and median NTproBNP was 2841.5 (289-10515) pg/mL. SGLT2i significantly reduced dPAP; average dPAP ("30 days after" period) was 1.5 mmHg lower (95% CI, 0.26-2.74; p=0.021) compared to "30 days before" period (Figure 1). SGLT2i also reduced systolic PAP (-2.2 mmHg), mean PAP (-1.7 mmHg), NTproBNP (-183 pg/mL) and creatinine (-0.2 mg/dL), but not statistically significant. SGLT2i reduced PAP, NTproBNP and creatinine too in group 1 (6 patients), but did not achieve statistical significance. Reductions were as well observed in group 2 (11 patients), and SGLT2i significantly reduced dPAP (-2.04 mmHg) (95% CI, 0.31-3.77; p=0.025). Conclusions In patients with chronic HF and a PAP sensor, SGLT2i, added to previous HF treatment, significantly reduced dPAP. PAP reductions were observed regardless LVEF, but results were more robust in patients with LVEF >40%.Figure 1

A hydrogel sensor based on conic baston structure

AbstractResistive flexible pressure sensors are extensively employed in wearable devices owing to their wide operational range and straightforward construction. This study presents a conic bastion‐structured sensor microunit to improve the sensor sensitivity. The base hydrogel is synthesized using acrylamide (AM), with Mg2+ and Na+ acting as conductive ions. The sensor is fabricated using digital light processing (DLP) 3D printing technology and is subjected to experimental evaluation. The findings indicate that the hydrogel sensor with a 50 wt% AM composition demonstrates enhanced mechanical strength and conductive properties, achieving a peak sensitivity of 0.534 kPa−1 within a pressure range of 0–0.8 kPa. Furthermore, the sensor exhibits favorable response characteristics (30 ms) and recovery characteristics (40 ms), along with stability. The proposed sensor is suitable for wearable devices and live joint angle detection. Additionally, the “handwriting fingerprint” pattern recognition and document verification proposed in this article make it applicable in scenarios, such as banking, notarization, and other handwriting and seal verification contexts.

Research on the distribution of debris flow impact on the upstream surface of the check dam

The impact force of debris flow is not only an important indicator of the risk assessment of debris flow and the strength impact resistance of buildings against debris flow, but also an important parameter in the design of various debris flow prevention projects (such as the check dam and the drainage channel, etc.). The pressure sensors are arranged at different positions (monitoring points) on the upstream face of the check dam. By changing the slope of the drainage channel, the bulk density of debris flow and the slope gradient of the upstream face of the check dam, the time history curves of the impact force at the monitoring points under different experiment conditions are obtained. The characteristic value of the impact force of debris flow acting on the surface of the sand retaining dam is analyzed, and the evolution law of mean value and maximum value of impact force of debris flow at the same detection location with the above conditions is obtained. The mean value and maximum value of debris flow impact force at different detection locations under the same working condition are analyzed to obtain the evolution law of debris flow impact force at different locations, and then the distribution trend of debris flow impact force on the upstream face of the check dam is obtained. The research results provide scientific and reasonable theoretical basis and technical support for the stability analysis of the check dam, so as to better serve the disaster prevention and reduction of debris flow, which will improve the technical level of the debris flow prevention project to a certain extent.

Anisotropic piezoresistive response of 3D-printed pressure sensor based on ABS/MWCNT nanocomposite

Nanocomposites based on carbon nanotubes (CNTs) are suitable for sensors, due to matrix ability to incorporate nanotube properties. Thus, we developed a low-cost, nanostructured poly(acrylonitrile-butadiene-styrene) (ABS) polymer piezoresistive sensor produced by additive manufacturing. For this, solution layers of acetone, dimethylformamide and CNTs functionalized with carboxylic acid were pulverized on an ABS substrate using an aerograph. Electrical characterization revealed an anisotropic piezoresistive response of the material, induced by the printing lines direction. Field Emission Gun-Scanning Electron Microscopy showed the nanostructured film spreading after five layers of CNTs as well as the random entanglement of nanotubes on parallel and perpendicular 3D-printed ABS substrates. Raman spectroscopy indicated compression and p-type doping of CNTs in interaction with the polymer, as seen mainly by the blueshift of the G and 2D subbands. The results show that the material is promising for pressure sensors, with potential applications in robotic haptic feedback systems.

A Flexible Smart Healthcare Platform Conjugated with Artificial Epidermis Assembled by Three-Dimensionally Conductive MOF Network for Gas and Pressure Sensing

The rising flexible and intelligent electronics greatly facilitate the noninvasive and timely tracking of physiological information in telemedicine healthcare. Meticulously building bionic-sensitive moieties is vital for designing efficient electronic skin with advanced cognitive functionalities to pluralistically capture external stimuli. However, realistic mimesis, both in the skin’s three-dimensional interlocked hierarchical structures and synchronous encoding multistimuli information capacities, remains a challenging yet vital need for simplifying the design of flexible logic circuits. Herein, we construct an artificial epidermal device by in situ growing Cu3(HHTP)2 particles onto the hollow spherical Ti3C2Tx surface, aiming to concurrently emulate the spinous and granular layers of the skin’s epidermis. The bionic Ti3C2Tx@Cu3(HHTP)2 exhibits independent NO2 and pressure response, as well as novel functionalities such as acoustic signature perception and Morse code-encrypted message communication. Ultimately, a wearable alarming system with a mobile application terminal is self-developed by integrating the bimodular senor into flexible printed circuits. This system can assess risk factors related with asthmatic, such as stimulation of external NO2 gas, abnormal expiratory behavior and exertion degrees of fingers, achieving a recognition accuracy of 97.6% as assisted by a machine learning algorithm. Our work provides a feasible routine to develop intelligent multifunctional healthcare equipment for burgeoning transformative telemedicine diagnosis.