A novel kind of fiber optic ultrasonic sensor based on matching fiber Bragg gratings (FBGs) is proposed and demonstrated. The sensors consist of a pair of matching FBGs fixed to a special bracket. ...The bracket plays a role in stretching and squeezing the FBGs, with the push⁻pull effect efficiently coupling the ultrasonic signal to the sensor, thus, improving the sensor's sensitivity. Side-band filtering technology-based intensity interrogation was used to detect ultrasounds in water. With the synergic effect of the matching FBGs, the sensor performed with a high signal-to-noise ratio (56.9 dB at 300 KHz, 53 dB at 1 MHz and 31.8 dB at 5 MHz) and the observed ultrasonic sinusoidal signals were undistorted and distinguishable in the time domain.
A sensitivity-improved ultrasonic sensor is proposed and demonstrated experimentally in this present study. The device is comprised only a fiber-optic microcavity that is formed by discharging a ...short section of hollow core fiber (HCF). The key to ensuring the success of the sensor relies on the preprocessing of hydrogen loading for HCF. When discharging the HCF, the hydrogen is heated up during the formation of the air bubble, which enlarges the bubble diameter, smoothens its surfaces simultaneously and decreases Young's modulus of the material of the bubble. Ultimately, this results in the probe being highly sensitive to ultrasound with a SNR of 69.28 dB. Once the compact air cavity is formed between the end face of the leading-in fiber and the top wall of the bubble, a well-defined interference spectrum is achieved based on the Fabry⁻Perot interference. By using spectral side-band filtering technology, we detect the ultrasonic waves reflected by the seismic physical model (SMF) and then reconstruct its three-dimensional image.
We detected human metapneumovirus (HMPV) in 72 (7.1%) of 1,021 patients hospitalized with severe acute respiratory infection in Luohe, China, during 2017-2019. We detected HMPV most frequently in ...young children and less often in adults. HMPV genotype A2c variants 111 nt and 180 nt duplications predominated, demonstrating their continuing geographic spread.
A simultaneous relative humidity (RH) and temperature sensor based on an optical fiber Fabry-Perot interferometer is proposed and experimentally demonstrated. This sensor is constructed by splicing a ...short length of photonic crystal fiber (PCF) to single mode fiber and coating an ultrathin polyvinyl alcohol film to the PCFs cleaved surface. The total length of this sensing head is only ~110 μM and the compact size means it can be used flexibly in limited space and harsh environments. Experimental results demonstrate that this sensor can simultaneously measure the ambient RH and temperature by demodulating the power change and wavelength shift of reflection spectrum. Consequently, the advantages of compact size, low cost, high flexibility and stability, fast response, and simultaneous RH and temperature measurement ability means the proposed sensor has an extensive range of potential applications.
Musical Performance Anxiety (MPA) is a multifaceted issue that exists on a spectrum of severity, necessitating an exploration of the underlying factors that hinder or reduce it within musical ...educational environments. Self-efficacy and motivation are widely recognized as significant determinants in the context of musical performance. Motivation has been a focal point in music education research, underscoring its importance in educational psychology and other skill-based performance domains. A comprehensive understanding of motivation is essential for elucidating students' achievements, performance, well-being, and intentions in music education. This study aims to investigate the impact of music students' self-efficacy and motivation on their MPA by analyzing data from 557 music participants who completed scales related to self-efficacy, motivation, and MPA. The research had a correlation-based research approach, typical in descriptive quantitative studies. The findings indicated that there exists a notable negative correlation between self-efficacy and MPA, as well as between motivation and MPA. In contrast, a substantial constructive correlation emerged between motivation and self-efficacy, indicating the interrelated nature of these constructs within the context of the study. The findings of the study through Structural Equation Modeling (SEM) indicated that a substantial proportion, estimated at around 54 %, of the variability evident in MPA among music students can be ascribed to the collective impact exerted by their levels of self-efficacy and motivation. Indeed, higher levels of self-efficacy and motivation are associated with lower degrees of MPA, suggesting that nurturing these attributes could potentially enhance music students’ overall performance. The paper provides recommendations for teaching participants in musical education.
Numerous studies have verified that electroacupuncture (EA) can relieve neuropathic pain through a variety of mechanisms. Synaptotagmin 1 (Syt-1), a synaptic vesicle protein for regulating exocytosis ...of neurotransmitters, was found to be affected by EA stimulation. However, the roles of Syt-1 in neuropathic pain and EA-induced analgesic effect remain unclear. Here, the effect of Syt-1 on nociception was assessed through an antibody blockade, siRNA silencing, and lentivirus-mediated overexpression of spinal Syt-1 in rats with spared nerve injury (SNI). EA was used for stimulating bilateral "Sanjinjiao" and "Zusanli" acupoints of the SNI rats to evaluate its effect on nociceptive thresholds and spinal Syt-1 expression. The mechanically and thermally nociceptive behaviors were assessed with paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) at different temperatures, respectively, at day 0, 7, 8, 14, and 20. Syt-1 mRNA and protein levels were determined with qRT-PCR and Western blot, respectively, and its distribution was observed with the immunohistochemistry method. The results demonstrated Syt-1 antibody blockade and siRNA silencing increased ipsilateral PWTs and PWLs of SNI rats, while Syt-1 overexpression decreased ipsilateral PWTs and PWLs of rats. EA significantly attenuated nociceptive behaviors and down-regulated spinal Syt-1 protein levels (especially in laminae I-II), which were reversed by Syt-1 overexpression. Our findings firstly indicate that Syt-1 is involved in the development of neuropathic pain and that EA attenuates neuropathic pain, probably through suppressing Syt-1 protein expression in the spinal cord.
A compact fiber Bragg grating (FBG) vibration sensor consisting a flat diaphragm and two L-shaped rigid cantilever beams for seismic measurement has been proposed and experimentally demonstrated. The ...specially designed sensing configuration contributes many desirable features such as a wide frequency response range (10-120 Hz), an extremely high sensitivity coefficient (~100pm/g) together with a robust metal package for improving the mechanical strength and a decreased transverse sensitivity (<; 5%), making it a good candidate for in-field seismic wave measurement in oil and gas exploration.
An in-fiber Mach-Zehnder interferometer (MZI) for high-sensitive refractive index (RI) measurement is proposed and experimentally demonstrated. The sensing head is formed by a single-mode fiber (SMF) ...sandwiched between two short sections of thin-core fibers (TCFs), i.e., TCF-SMF-TCF MZI configuration with a length of 9 mm. A well-defined interference pattern is obtained as the result of fiber-core mismatch and core-cladding modes interference. The selected interference dip is extremely sensitive to ambient RI, providing a stable RI response with sensitivity up to 159 nm/RIU for water-based solutions close to the RI of 1.33, making it a good candidate for bio-chemical measurements.
A compact fiber Bragg grating (FBG) accelerometer based on a hybridization of two cantilever beams is demonstrated. Two FBGs are prestressed and fixed on the combined-beam longitudinal symmetrically. ...When a vibration is exerted on the accelerometer, the reflection-peaks of two gratings shift sharply in opposite directions without unwanted chirp. Experimental results show that the proposed sensor exhibits a high dynamic sensitivity of 218.4 pm/G and broad frequency range of 10-150 Hz with a wide dynamic range of 0.1 to 3 G. The cross-axis response is 3.2% of the main axis, and the temperature is self-compensated owing to the same responses to temperature of two reflection wavelengths.
Human cellular reprogramming to induced pluripotency is still an inefficient process, which has hindered studying the role of critical intermediate stages. Here we take advantage of high efficiency ...reprogramming in microfluidics and temporal multi-omics to identify and resolve distinct sub-populations and their interactions. We perform secretome analysis and single-cell transcriptomics to show functional extrinsic pathways of protein communication between reprogramming sub-populations and the re-shaping of a permissive extracellular environment. We pinpoint the HGF/MET/STAT3 axis as a potent enhancer of reprogramming, which acts via HGF accumulation within the confined system of microfluidics, and in conventional dishes needs to be supplied exogenously to enhance efficiency. Our data suggest that human cellular reprogramming is a transcription factor-driven process that it is deeply dependent on extracellular context and cell population determinants.
PDF
