Ambient floor vibration sensing advances the accessibility of functional gait assessments for children with muscular dystrophies.

Muscular dystrophies (MD) are a group of genetic neuromuscular disorders that cause progressive weakness and loss of muscles over time, influencing 1 in 3500-5000 children worldwide. New and exciting treatment options have led to a critical need for a clinical post-marketing surveillance tool to confirm the efficacy and safety of these treatments after individuals receive them in a commercial setting. For MDs, functional gait assessment is a common approach to evaluate the efficacy of the treatments because muscle weakness is reflected in individuals' walking patterns. However, there is little incentive for the family to continue to travel for such assessments due to the lack of access to specialty centers. While various existing sensing devices, such as cameras, force plates, and wearables can assess gait at home, they are limited by privacy concerns, area of coverage, and discomfort in carrying devices, which is not practical for long-term, continuous monitoring in daily settings. In this study, we introduce a novel functional gait assessment system using ambient floor vibrations, which is non-invasive and scalable, requiring only low-cost and sparsely deployed geophone sensors attached to the floor surface, suitable for in-home usage. Our system captures floor vibrations generated by footsteps from patients while they walk around and analyzes such vibrations to extract essential gait health information. To enhance interpretability and reliability under various sensing scenarios, we translate the signal patterns of floor vibration to pathological gait patterns related to MD, and develop a hierarchical learning algorithm that aggregates insights from individual footsteps to estimate a person's overall gait performance. When evaluated through real-world experiments with 36 subjects (including 15 patients with MD), our floor vibration sensing system achieves a 94.8% accuracy in predicting functional gait stages for patients with MD. Our approach enables accurate, accessible, and scalable functional gait assessment, bringing MD progressive tracking into real life.

Submarine cable monitoring system based on enhanced COTDR with simultaneous loss measurement and vibration monitoring ability.

A submarine cable monitoring system based on enhanced coherent optical time-domain reflectometry (E-COTDR) is realized. An improved optimal peak-seeking (OPS) based I/Q demodulation method is employed for simultaneous loss measurement and vibration monitoring. A single-end diagnosis range over 74km is achieved for the proposed E-COTDR, enabling the double-end cooperative system to have a single-span of 148km. For the multi-span cascaded cables over 1000km, the loss and vibration monitoring without fading zone is carried out for a single-span of 121km. The proposed system provides a reliable technical option for the next generation underwater cable monitoring applications.

A Space-Division Multiplexing Method for Fading Noise Suppression in the Φ-OTDR System.

Phase-sensitive time-domain reflectometry (Φ-OTDR) can be used for fully distributed long-distance vibration monitoring. There is a fading phenolmenon in the Φ-OTDR, which will cause the signal intensity somewhere to be too low to extract the phase of the signal without distortion. In this paper, the Φ-OTDR based on space-division multiplexing (SDM) is proposed to suppress fading and we used multi-core optical fiber (MCF) to realize SDM. While inheriting the previous optimization strategy, we proposed a strategy based on frequency spectral similarity to process multiple independent signals obtained by SDM. And we compared the two methods. Through the experiments, the distortion rate can be reduced from an average level of 9.34% to less than 2% under continuous running of 270 s, which proves that SDM is a reliable technical route to achieve fading suppression. This method can effectively improve the fading suppression capability of the existed commercial systems.

Compensation of optical path difference in heterodyne Φ-OTDR systems and SNR enhancement by generating multiple beat signals.

In conventional heterodyne phase-sensitive optical time domain reflectometry (Φ-OTDR), the optical path difference (OPD) between sensing and reference arms deteriorates the signal-to-noise ratio (SNR). We counteract this effect by introducing a loop path in reference arm. This facilitates the use of laser source with low coherence length. Compared with an ordinary Φ-OTDR system, SNR increased from ~1 dB to 5 dB. Regardless of OPD compensation features, the probability to getting a better output increases by generation of multiple reference beams (and consequently multiple beat signals), as compared to conventional systems. The method is cost efficient and suitable for practical purposes.

Dynamic responses, GPS positions and environmental conditions of two light rail vehicles in Pittsburgh.

We present DR-Train, the first long-term open-access dataset recording dynamic responses from in-service light rail vehicles. Specifically, the dataset contains measurements from multiple sensor channels mounted on two in-service light rail vehicles that run on a 42.2-km light rail network in the city of Pittsburgh, Pennsylvania. This dataset provides dynamic responses of in-service trains via vibration data collected by accelerometers, which enables a low-cost way of monitoring rail tracks more frequently. Such an approach will result in more reliable and economical ways to monitor rail infrastructure. The dataset also includes corresponding GPS positions of the trains, environmental conditions (including temperature, wind, weather, and precipitation), and track maintenance logs. The data, which is stored in a MAT-file format, can be conveniently loaded for various potential uses, such as validating anomaly detection and data fusion as well as investigating environmental influences on train responses.

Facile synthesis of urchin-like Cs x WO3 particles with improved transparent thermal insulation using bacterial cellulose as a template.

Urchin-like Cs x WO3 particles were synthesized using bacterial cellulose (BC) as a template by the hydrothermal method. The effects of the BC addition amount on the morphology, W5+ content and transparent thermal insulation of Cs x WO3 were studied. It has been confirmed that abnormal growth of Cs x WO3 rods was greatly reduced after introduction of BC into the precursor solution. Moreover, introduction of BC into the precursor solution could significantly improve the transparent thermal insulation properties of the Cs x WO3 film. In particular, when the BC amount was appropriate, the prepared Cs x WO3 film exhibited better visible transparency, with the visible light transmittance (T Vis) more than 60%. In addition, the urchin-like particles could be transformed into small size nanorods after H2 heat-treatment, exhibiting excellent visible light transparency and thermal insulation performance. In particular, it has been proved that the 20BC-HT-Cs x WO3 film exhibits excellent thermal insulation performance, and shows broad application prospects in the field of solar heat filters and energy-saving window glass.

Preparation and properties of plate-like titanate (PLT)/calcia-doped ceria (CDC) composites by sol-gel coating method.

In order to obtain UV-shielding materials with good comfort, higher safety and effective UV-shielding ability, lepidocrocite type plate-like titanate (K(0.8)Li(0.27)Ti(1.73)O(4), donated as: PLT)/calcia-doped ceria (donated as: CDC) composites were synthesized by a sol-gel method. After dissolving Ce(NO(3))(3).6H(2)O and Ca(NO(3))(2).4H(2)O into absolute ethanol at 40 degrees C, glacial acetic acid (HAc) and PLT particles dispersed into absolute ethanol were added. Then, the solution was heated at 60 degrees C to get gel-like substance. This gel was dried in a vacuum oven at 333 K for 5 h, and then, the product was collected and ground in an agate mortar followed by calcination at 1073 K for 2 h to form PLT/CDC composites. By optimization, 20 mass% of CDC was coated by one operation. PLT/CDC composites with higher CDC content were obtained by repeating the coating process. The morphology, catalytic activity for the oxidation of organic material, UV-shielding ability and dynamic friction coefficient of as-obtained PLT/CDC composites were characterized. As a result, broad-spectrum UV-shielding composite materials with good comfort and low oxidation catalytic activity were successfully synthesized.

[Progress on reasech of drug-coated stent].

Drug-coated stent play an important role in percutaneous transluminal coronary angioplasty (PTCA), and it constitutes an innovation to further reduce the incidence of restenosis. In this paper, the mechanisms and the process of endovascular stent implantation,and the principles of drug release of drug-coated stent are reviewed. Especially, polymer coated design and the further development of drug eluting stents are discussed.

[Preparation of hydroxyapatite coating in concentrated simulated body fluid by accelerated biomimetic synthesis].

In the present work, NiTi alloy substrates were activated by three different pretreatment processes. 5 X SBF1 and 5 X SBF2 concentrated simulated body fluids were prepared with citric acid buffer reagent, and then calcium phosphate coatings were formed quickly on NiTi alloy surface by accelerated biomimetic synthesis after pretreatment. The microstructure, composition and surface morphology of calcium phosphate coatings were studied. The results indicate that calcium phosphate coatings possess porous and net structure, which are composed of precipitated spherical particles with diameter less than 3 microm. The analysis of XRD shows that the main component of calcium phosphate coatings is hydroxyapatite, whereas the concentrated 5 x SBF simulated body fluid, which is in the absence of Mg2+ and HCO3- crystal growth inhibitors, apparently accelerates the growth rate of hydroxyapatite coatings.