Negative pressure wound therapy relies on suction, commonly set to -125 mmHg, to evacuate wound fluid, but dysvascular and pressure injuries often respond unpredictably. Newton's third law indicates that negative pressure applies an equal and opposite contact pressure on the wound surface, and this study quantified this contact pressure across dressing types, wound configurations and suction levels. Using a porcine explant model, central and peripheral contact pressure measurements were obtained beneath black reticulated open cell foam, white foam and a novel thermoplastic elastomer dressing across plexiglass, intact skin, shallow and deep wounds under -50, -75 and -125 mmHg. Contact pressure increased proportionally with negative pressure, and multivariable modelling demonstrated that dressing type, wound type and suction level significantly influenced pressure, with negative pressure explaining most of the variance (0.77 and 0.68). Thermoplastic elastomer at -50 mmHg in deep wounds produced the lowest contact pressure, whereas black reticulated open cell foam and white foam at -125 mmHg generated elevated contact pressures of approximately +125 to +195 mmHg. These findings show that black reticulated open cell foam at conventional -125 mmHg can create hypoperfusion conditions, whereas thermoplastic elastomer consistently produces the lowest pressures and may enhance perfusion at lower suction levels, offering a physiologic explanation for improved clinical outcomes in dysvascular and pressure injuries treated with reduced negative pressure.
Abstract:Computed tomography-based robotic-arm-assisted total knee arthroplasty (RATKA) enables three-dimensional surgical planning and intraoperative adjustment of implant positioning based on ligament laxity. Stability and kinematic assessments may offer enhanced insight into multiplanar knee laxity, but their reproducibility remains underexplored. This study evaluated the reliability of intraoperative knee kinematic (dynamic), sagittal and transverse stability assessments in a cadaver setting under different support conditions. Cruciate-retaining RATKA was performed on five fresh-frozen cadaver knees by three experienced surgeons. Medial and lateral anteroposterior translation (MAP, LAP) and internal-external rotation (IE) were measured at 10, 45, and 90 degrees of flexion before and after component implantation. Dynamic assessments across the full range of motion were used to calculate the average medial contact position (AMCP) and medial pivot ratio (MPR). Inter- and intra-rater reliability were determined using intraclass correlation coefficients (ICC: poor < 0.4, good 0.4 to 0.74, and excellent ≥ 0.75). Analyses compared a leg-holder-only condition with all surgeons, including manual support. Intra- and inter-rater reliability across all surgeons was generally good to excellent. For intact knees, reliability ranged from ICC 0.52 to 0.84 for MAP, 0.44 to 0.57 for LAP, and 0.48 to 0.62 for IE. With components, reliability remained good to excellent for MAP, LAP, and IE (ICC 0.47 to 0.80). Dynamic AMCP assessments demonstrated excellent inter-rater reliability (ICC 0.84 to 0.93), while MPR showed good reliability (ICC 0.57). The leg holder reduced variance for MAP/LAP and IE, maintaining error within two mm or 5 degrees, respectively. Intra-rater reliability was consistently excellent across nearly all measures (ICC 0.69 to 0.99). Intraoperative stability and kinematic assessments during RATKA are reproducible, particularly for AMCP. The leg holder generally improved consistently across observers and reduced variance. These findings support the reliability of robotic-assisted intraoperative stability and kinematic measures for evaluating knee function and guiding surgical planning.
BACKGROUND:Negative pressure wound therapy promotes wound healing through fluid removal, edema reduction, and mechanical contraction. A novel thermoplastic elastomer (TPE) dressing has been developed to improve exudate evacuation and reduce tissue ingrowth, but its effect on wound contraction compared with reticulated open cell foam (ROCF) remains unclear. OBJECTIVE:To compare the degree of wound contraction with the TPE dressing, ROCF, or no filler at different wound depths and negative pressure settings in a porcine explant model. MATERIALS AND METHODS:The effect of the materials or lack thereof on wound contraction was investigated at 2 wound depths (shallow, deep) and 3 negative pressure settings (-50 mm Hg, -80 mm Hg, and -125 mm Hg). Wound width was measured at 3 standardized locations before and during therapy. Univariable and multivariable linear regression analyses were performed to identify factors associated with contraction. RESULTS:A total of 810 measurements were obtained. Both the TPE dressing and ROCF demonstrated statistically significantly greater contraction than no filler. In deep wounds, greater contraction was noted with the TPE dressing compared with ROCF. Higher negative pressure and increased wound depth were independently associated with greater contraction. Absolute differences in contraction between dressings were small (<3 mm across all conditions). CONCLUSION:The TPE dressing provides equivalent or greater wound contraction compared with ROCF, particularly in deep wounds, without impairing macrodeformation. Given the small magnitude of differences, the clinical relevance of this finding likely depends on additional factors, which should be evaluated in future in vivo studies.
Cardiovascular diseases (CVDs) remain a major global health challenge, highlighting the urgent need for advanced cardiac monitoring solutions. Continuous, contactless cardiac monitoring using seismic sensors enables comfortable, privacy-preserving assessments by capturing subtle heart vibrations. However, these systems are highly susceptible to diverse noise sources. Existing denoising methods struggle to handle the complex noise in cardiac seismic signals and poorly leverage the abundant unlabeled data. To address these challenges, we propose SelfDenoiser, a self-supervised framework for denoising and reconstructing cardiac seismic signals using unlabeled data. During training, SelfDenoiser first selects clean segments from the unlabeled pool, then injects adaptive noise into each segment to simulate shared, hard-to-remove interference commonly observed in real-world noise distributions. In addition, realistic artifacts are extracted and integrated into clean signals to model high-intensity, abrupt noise events. An encoder-decoder network designed with fixed temporal resolution is subsequently trained to recover the clean signals, guided by a loss function that captures both temporal and spectral characteristics. We evaluated SelfDenoiser on 11,392 hours of data collected in an Intensive Care Unit (ICU) using seismic sensor-based systems. The model was trained on 610 hours of clean signals selected from a 5176-hour unlabeled pool and tested on a 6216-hour labeled dataset. Results showed substantial improvements in two downstream tasks: heart rate (HR) and inter-beat interval (IBI) estimation, with notably increased data utilization and better accuracy compared to conventional denoising methods. This highlights SelfDenoiser's capability to transform low-quality, noisy signals into high-fidelity, reliable cardiac data.
In March 2022, two geoarchaeological boreholes were drilled within the Avon Valley at the site of Jubilee Gardens, Ringwood, Hampshire. The works were commissioned from Connect Archaeology by VolkerFitzpatrick on behalf of their client, National Highways, as part of the A31 road widening and junction improvement works. One sequence was selected for palaeoenvironmental analysis and radiocarbon dating, aiming to provide evidence for landscape development in an area where such records are sparse. The results highlight two temporally removed phases of deposition. The early Neolithic base of the sequence illustrates the presence of alder carr and herbaceous wetland in the lower valley, with the higher land home to open grassland with copses of primarily hazel. Beyond the scheme footprint, Neolithic long barrows and Bronze Age barrow cemeteries were constructed among the higher grasslands, standing as prominent monuments overlooking the floodplain. It is possible that changing climate of the 2.8 ka event, bringing colder and wetter conditions, may have pushed people from the region as the rivers grew more powerful and eroded the ground around them. Such an event may explain the decline in regional human activity during the Iron Age period, as well as an absence of the channel's depositional sequence. By the early medieval period, conditions returned to deposition within the river channel, with herbaceous wetlands spreading through the lower valley, bringing a decline in alder carr, as agricultural field systems became prominent across the upper valley. Evidence for land reclamation and flood alleviation is shown throughout the 20th century as Ringwood grew.
