Numerical and experimental investigations on quasi-static component generation of longitudinal wave propagation in isotropic pipes.

In this paper, the quasi-static component (QSC) generation of longitudinal waves propagating in an isotropic pipe is investigated numerically and experimentally. The three-dimensional (3D) finite element (FE) simulations are first carried out to gain physical insights into the characteristics of QSC generation from longitudinal wave travelling in an isotropic pipe with weak material nonlinearity. By applying the axial displacement excitation in the FE model, L(0, 1) mode and L(0, 2) mode are excited simultaneously. Then, the generated QSC pulses are extracted using the phase reversal approach for analysis. It is found that the QSC pulses generated by L(0, 2) mode and L(0, 1) mode are L(0, 1) mode. Meanwhile, the shapes of QSC pulses at different locations are extracted and compared. In this study, a data pre-processing method is proposed to handle numerically calculated and subsequent experimentally measured displacement signals, and a nonlinear acoustic parameter is defined to evaluate the incipient damages. After that, an experiment is conducted to measure the QSCs induced by the propagation of longitudinal waves in an aluminum pipe. The experimental results indicate that the propagation of longitudinal waves in the aluminum pipe can induce the QSCs. Different levels of corrosion are created on the surface of the aluminum pipe and are assessed by the generated QSCs. The results show that the nonlinear acoustic parameter has a monotonically increasing trend with the growing severity of corrosion. The QSCs generated by longitudinal wave can be used to detect and evaluate the early-stage surface corrosion in the aluminum pipe.

Feasibility and basic acoustic characteristics of intelligent long-term bowel sound analysis in term neonates.

Objective: Bowel dysfunction continues to be a serious issue in neonates. Traditional auscultation of bowel sounds as a diagnostic tool in neonatal gastrointestinal problems is limited by skill and inability to document and reassess. Consequently, in order to objectively and noninvasively examine the viability of continuous assessment of bowel sounds, we utilized an acoustic recording and analysis system to capture bowel sounds and extract acoustic features in term neonates. Methods: From May 1, 2020 to September 30, 2020, 82 neonates who were hospitalized because of hyperbilirubinemia were included. For 20 h, a convolutional neural network-based acoustic recorder that offers real-time, wireless, continuous auscultation was employed to track the bowel sounds of these neonates. Results: (1) Usable data on five acoustic parameters of bowel sound was recorded for 68 neonates, and the median values were as follows: The rate was 25.80 times/min [interquartile range (IQR): 15.63-36.20]; the duration was 8.00 s/min (IQR: 4.2-13.20); the amplitude was 0.46 (IQR: 0.27-0.68); the frequency was 944.05 Hz (IQR: 848.78-1,034.90); and the interval time was 2.12 s (IQR: 1.3-3.5). (2) In comparison to the parameters of the bowel sounds recorded from the right lower abdomen in 68 infants, the acoustic parameters of the 10 out of 68 infants from chest controls and blank controls were considerably different. (3) The 50%-75% breast milk intake group had the highest rate, the longest duration, and the highest amplitude of bowel sounds, while the >75% breast milk intake group had the highest frequency of bowel sounds. (4) Compared with neonates without hyperbilirubinemia, there was no significant difference in the five parameters of bowel sounds in hyperbilirubinemia infants; nor was there a significant effect of phototherapy and non-phototherapy status on the parameters of bowel sounds during bowel sound monitoring in hyperbilirubinemia patients. (5) A mild transient skin rash appeared on the skin of three infants. No other adverse events occurred. Conclusion: The acoustic recording and analysis system appears useful for monitoring bowel sounds using a continuous, invasive, and real-time approach. Neonatal bowel sounds are affected by various feeding types rather than hyperbilirubinemia and phototherapy. Potential influencing factors and the significance of their application in neonatal intestinal-related disorders require further research.

The Effects of the Structural and Acoustic Parameters of the Skull Model on Transcranial Focused Ultrasound.

Transcranial focused ultrasound (tFUS) has great potential in brain imaging and therapy. However, the structural and acoustic differences of the skull will cause a large number of technical problems in the application of tFUS, such as low focus energy, focal shift, and defocusing. To have a comprehensive understanding of the skull effect on tFUS, this study investigated the effects of the structural parameters (thickness, radius of curvature, and distance from the transducer) and acoustic parameters (density, acoustic speed, and absorption coefficient) of the skull model on tFUS based on acrylic plates and two simulation methods (self-programming and COMSOL). For structural parameters, our research shows that as the three factors increase the unit distance, the attenuation caused from large to small is the thickness (0.357 dB/mm), the distance to transducer (0.048 dB/mm), and the radius of curvature (0.027 dB/mm). For acoustic parameters, the attenuation caused by density (0.024 dB/30 kg/m3) and acoustic speed (0.021 dB/30 m/s) are basically the same. Additionally, as the absorption coefficient increases, the focus acoustic pressure decays exponentially. The thickness of the structural parameters and the absorption coefficient of the acoustic parameters are the most important factors leading to the attenuation of tFUS. The experimental and simulation trends are highly consistent. This work contributes to the comprehensive and quantitative understanding of how the skull influences tFUS, which further enhances the application of tFUS in neuromodulation research and treatment.

Inhibitory effects of ultrasound irradiation on Staphylococcus epidermidis biofilm.

PURPOSE: We aimed to investigate whether low-intensity continuous and pulsed wave ultrasound (US) irradiation can inhibit the formation of Staphylococcus epidermidis biofilms, for potential application in the treatment of catheter-related bloodstream infections (CRBSI). METHODS: S. epidermidis biofilms that formed on the bottom surfaces of 6-well plates were irradiated on the bottom surface using the sound cell incubator system for different intervals of time. RESULTS: US irradiation with continuous waves for 24 h notably inhibited biofilm formation (p < 0.01), but the same US irradiation for 12 h had no remarkable effect. Further, double US irradiation with pulsed waves for 20 min inhibited biofilm formation by 33.6%, nearly two-fold more than single US irradiation, which reduced it by 17.9%. CONCLUSION: US irradiation of a lower intensity (ISATA = 6-29 mW/cm2) than used in a previous study and lower than recommended by the Food and Drug Administration shows potential for preventing CRBSI caused by bacterial biofilms.

[Application of dysphonia severity index in laryngeal reflux related voice diseases].

Objective:To discuss the validity and reliability of dysphonia severity index in evaluating the effect of diagnosis and treatment of laryngeal reflux related voice diseases. Method:54 cases of voice disease patients accompanied by laryngopharyngeal reflux from January 2016 to June 2017 in department of otorhinolaryngology of our hospital were divided into two groups according to treatment type. 32 cases in the operation group received laser surgery and standard acid suppression therapy for 6 weeks, and 22 patients in the non-operation group received standard acid suppression therapy for 6 weeks. 24 h multichannel impedance pH (MCII-pH) monitoring was carried out. The indexes of reflux symptom, reflux finding score, subjective auditory perception and objective acoustic parameters of voice were measured before and after treatment, and the dysphonia severity index was calculated and analyzed. Result:There was no significant difference in age, sex and course of disease between the two groups (P> 0.05).Compared with pre-treatment, RSI, RFS, Jitter, Shimmer, G and R in two groups decreased significantly after treatment, and MPT, DSI increased significantly (P<0.05). Before treatment, RSI, RFS, Jitter, Shimmer, G and R in the operation group were significantly higher than those in the non-operation group, and MPT, DSI were lower (P<0.05). There were no significant differences in the parameters between the two groups after treatment (P> 0.05). DSI was negatively correlated with GRBAS scoring parameters, Jitter and Shimmer, and positively correlated with RSI, RFS, and MPT (P<0.01). DSI is related to the location of the lesion (P<0.05) The incidence of anxiety was 27.27% in patients with moderate and severe sudden sensorineural hearing loss, and the incidence of depression was 25.25%. The scores of anxiety and depression were statistically significant (P<0.05). The multivariate logistic regression analysis showed that the status of anxiety and depression was accompanied by symptoms and other diseases (P<0.05). There was a significant difference between the effective group, the significant efficacy group and the cured group (P<0.05). The difference between the scores before and after treatment was compared. Differences in the ineffective group compared with the other three groups, and the cured group compared with the other three groups of anxiety, depression were statistically significant. Conclusion:DSI can be used as an objective evaluation index for the diagnosis and treatment of laryngeal reflux related voice diseases, and it is accurate and reliable.

Acoustic Outcomes After Laryngomicrosurgery for Reinke's Edema

BACKGROUND AND OBJECTIVES: The management of Reinke's edema includes usually medical treatment and voice therapy. Laryngomicrosurgery (LMS) is also necessary, especially to improve airway obstruction. However, voice outcome after LMS has not been determined well. The aim of this study was to evaluate effectiveness of LMS for Reinke's edema and analyze the voice outcomes after LMS. MATERIALS AND METHODS: Twenty-five patients with Reinke's edema who underwent LMS from September 2007 to December 2016 were enrolled in this study. We analyzed reflux finding score (RFS), reflux symptom index (RSI), and acoustic parameters before and after surgery. RESULTS: Male was 15 (60%) and female was 10 (40%), and mean age was 49.6 years. Preoperative mean value of RFS decreased significantly up to 3 months after LMS (18.3±2.2 and 10.0±2.2 at preoperative and 3 months postoperatively, respectively). The mean value of Jitter decreased significantly before and after surgery (2.71±2.81% and 1.06±1.21% before and after LMS, p=0.041). The mean value of Shimmer also decreased significantly before and after surgery (7.97±3.63% and 4.83±1.85%, respectively, p=0.006). CONCLUSION: LMS is effective in the treatment of Reinke's edema. It results in favorable acoustic outcomes and laryngoscopic findings in properly selected patients.

Acoustic parameters and salivary IL-6 levels in overweight and obese teachers.

OBJECTIVE: Either obesity or vocal loading task leads to elevation of proinflammatory cytokines such as interleukin 6 (IL-6). However, it is unknown whether vocal parameters after vocal loading are correlated with body mass index (BMI) or IL-6. We hypothesize that vocal loading induces an elevation of acoustic parameters of voice and salivary IL-6 in overweight and obese people. METHODS: A total of 33 schoolteachers without any self-reported voice alterations were invited to participate in this study. Participants were classified according to BMI into normal, overweight, and obese groups. The vocal loading task consisted of loud speech (60-90 minutes) in their classroom. Salivary and voice samples were taken before and after vocal loading. Perceptual and self-reported voice alterations and objective voice analyses were investigated. The relative concentration of salivary IL-6 was estimated by a colorimetric assay. RESULTS: Obese teachers showed a significant elevation in fundamental frequency value after vocal loading. In addition, reduction in harmonics-to-noise ratio (HNR) was observed in teachers with normal weight after vocal loading but not in overweight or obese groups. No significant correlation was observed between BMI and any of the acoustic parameters analyzed or salivary IL-6 levels. Furthermore, teachers who were overweight showed a significant increase in the salivary IL-6 levels after vocal loading. Interestingly, salivary IL-6 levels were positively correlated with HNR value in the overweight group after vocal loading. CONCLUSION: Excessive body weight is related to alterations in fundamental frequency and HNR. In addition, HNR, but not BMI, is associated with salivary IL-6 levels in overweight teachers.