Contamination, ecological-health risks, and sources of potentially toxic elements in road-dust sediments and soils of the largest urban riverfront scenic park in China.

Identifying the contamination and sources of potentially toxic elements (PTEs) in road-dust sediment (RDS) and the surrounding greenspace soil of urban environments and understanding their ecological-health risks are important for pollution management and public health. The contamination characteristics, ecological and probabilistic health risks, and source apportionment of eight PTEs (Cd, Pb, Cr, Cu, Ni, As, Zn, and Hg) in the Yellow River Custom Tourist Line of Lanzhou, which is the largest open urban riverfront scenic park in China, were investigated. The results showed that all the RDS PTE mean concentrations exceeded their soil background values, whereas for the surrounding greenspace soils, the concentrations of the PTEs, except for Cr and Ni, were also higher than their local background levels. Moreover, the RDS-soil system was mainly contaminated by Cd, Zn, Pb, Cu, and Hg to varying degrees, and the integrated ecological risks of PTEs in the RDS and soil were high and considerable at most sites, respectively. The probabilistic health risk assessment results demonstrated that the non-carcinogenic hazard risk for humans was negligible, but the total carcinogenic risks should be considered. Source apportionment using a positive matrix factorization model combined with multivariate statistical analyses revealed that Cr, Ni, and As in the RDS-soil system were from natural and industrial sources, Cd, Pb, Zn, Cu came from vehicle emissions and pesticide and fertilizer applications, and Hg was from natural and industrial sources and utilization of pesticides with fertilizers. This work provides scientific evidence for urban planning and human health protection in urban environments.

Disrupted intrinsic functional brain topology in patients with major depressive disorder.

Aberrant topological organization of whole-brain networks has been inconsistently reported in studies of patients with major depressive disorder (MDD), reflecting limited sample sizes. To address this issue, we utilized a big data sample of MDD patients from the REST-meta-MDD Project, including 821 MDD patients and 765 normal controls (NCs) from 16 sites. Using the Dosenbach 160 node atlas, we examined whole-brain functional networks and extracted topological features (e.g., global and local efficiency, nodal efficiency, and degree) using graph theory-based methods. Linear mixed-effect models were used for group comparisons to control for site variability; robustness of results was confirmed (e.g., multiple topological parameters, different node definitions, and several head motion control strategies were applied). We found decreased global and local efficiency in patients with MDD compared to NCs. At the nodal level, patients with MDD were characterized by decreased nodal degrees in the somatomotor network (SMN), dorsal attention network (DAN) and visual network (VN) and decreased nodal efficiency in the default mode network (DMN), SMN, DAN, and VN. These topological differences were mostly driven by recurrent MDD patients, rather than first-episode drug naive (FEDN) patients with MDD. In this highly powered multisite study, we observed disrupted topological architecture of functional brain networks in MDD, suggesting both locally and globally decreased efficiency in brain networks.

Reduced default mode network functional connectivity in patients with recurrent major depressive disorder.

Major depressive disorder (MDD) is common and disabling, but its neuropathophysiology remains unclear. Most studies of functional brain networks in MDD have had limited statistical power and data analysis approaches have varied widely. The REST-meta-MDD Project of resting-state fMRI (R-fMRI) addresses these issues. Twenty-five research groups in China established the REST-meta-MDD Consortium by contributing R-fMRI data from 1,300 patients with MDD and 1,128 normal controls (NCs). Data were preprocessed locally with a standardized protocol before aggregated group analyses. We focused on functional connectivity (FC) within the default mode network (DMN), frequently reported to be increased in MDD. Instead, we found decreased DMN FC when we compared 848 patients with MDD to 794 NCs from 17 sites after data exclusion. We found FC reduction only in recurrent MDD, not in first-episode drug-naïve MDD. Decreased DMN FC was associated with medication usage but not with MDD duration. DMN FC was also positively related to symptom severity but only in recurrent MDD. Exploratory analyses also revealed alterations in FC of visual, sensory-motor, and dorsal attention networks in MDD. We confirmed the key role of DMN in MDD but found reduced rather than increased FC within the DMN. Future studies should test whether decreased DMN FC mediates response to treatment. All R-fMRI indices of data contributed by the REST-meta-MDD consortium are being shared publicly via the R-fMRI Maps Project.

On the three-dimensional sound fields from a moving monopole source above a non-locally reacting ground.

This study derives an accurate analytic solution for sound fields due to a moving point monopole source above a non-locally reacting ground. Based on the property of the invariant phase function, the acoustic pressure and normal particle velocity are matched across the air/ground interface in the frequency-wave number domain. Expressions for the integral form of the sound fields in three different frames are used to analyze and compare the original physical frame in the reception time geometry, the Lorentz frame, and the emission time frame. For ease of interpretation, the final form of the asymptotic solution is expressed in the geometry of the emission time frame. The accuracy of the asymptotic solution is validated using the direct numerical integration technique. The three-dimensional point source solution derived from the current study is compared with that of the two-dimensional line source solution. Explicit comparisons of the cylindrical and spherical wave reflection coefficients are available, allowing a better understanding of the impact of the ground wave term in the vicinity of a non-locally reflecting plane. Finally, contour plots are presented that demonstrate the need to employ the asymptotic formula for the non-locally reacting ground instead of approximating it with a locally reacting property.

Microstructural brain abnormalities in medication-free patients with major depressive disorder: a systematic review and meta-analysis of diffusion tensor imaging.

BACKGROUND: Multiple meta-analyses of diffusion tensor imaging (DTI) studies have reported impaired white matter integrity in patients with major depressive disorder (MDD). However, owing to inclusion of medicated patients in these studies, it is difficult to conclude whether these reported alterations are associated with MDD or confounded by medication effects. A meta-analysis of DTI studies on medication-free (medication-naive and medication washout) patients with MDD would therefore be necessary to disentangle MDD-specific effects. METHODS: We analyzed white matter alterations between medication-free patients with MDD and healthy controls using anisotropic effect size-signed differential mapping (AES-SDM). We used DTI query software for fibre tracking. RESULTS: Both pooled and subgroup meta-analyses in medication washout patients showed robust fractional anisotropy (FA) reductions in white matter of the right cerebellum hemispheric lobule, body of the corpus callosum (CC) and bilateral superior longitudinal fasciculus III (SLF III), whereas FA reductions in the genu of the CC and right anterior thalamic projections were seen in only medication-naive patients. Fibre tracking showed that the main tracts with observed FA reductions included the right cerebellar tracts, body of the CC, bilateral SLF III and arcuate fascicle. LIMITATIONS: The analytic techniques, patient characteristics and clinical variables of the included studies were heterogeneous; we could not exclude the effects of nondrug therapies owing to a lack of data. CONCLUSION: By excluding the confounding influences of current medication status, findings from the present study may provide a better understanding of the underlying neuropathology of MDD.

[The Application of Internal Iliac Artery Balloon Occlusion in Pernicious Placenta Previa].

OBJECTIVES: To evaluate the clinical application value of internal iliac artery balloon occlusion in pernicious placenta previa. METHODS: We retrospectively reviewed the medical records of the patients of pernicious placenta previa in a single center from Jan, 2010 to Jan, 2015. The patients were divided into two groups, internal iliac artery balloon occlusion group and the control group without endovascular intervention. Blood loss in operation, volume of transfused blood products, caesarean hysterectomy, operating time, hospital days after operation and postoperative morbidity were compared between the two groups. RESULTS: The balloon occlusion group had significantly less blood loss, the volume of transfused blood products, caesarean hysterectomy, hospital day after operation than the control group had. There was no statistical difference in operating time, intensive care units (ICU), hypotension, infection, hypoxemia, bladder injury, bowel obstruction, neonatal asphyxia between the two groups. The balloon occlusion group had significantly higher rate in coagulopathy, hypoalbuminemia, electrolyte imbalance. Among the patients whose uterus were preserved, the blood loss was not significantly difference between the two groups. Among the patients with the complication of placenta accreta, caesarean hysterectomy was less in balloon group, and blood loss between the two groups was not significantly different. Among the patients without placenta accrete, the blood loss was less in balloon group, and caesarean hysterectomy between the two groups was not significantly different. The risk of hysterectomy in balloon group was related to placenta accreta, uterine arteries engorgement, placental invasive serosa, taking placenta by hand, placental invasive bladder, barrel-shaped thickening of lower uterine segment, unable to remove placenta. CONCLUSIONS: Internal iliac artery balloon occlusion is an effective treatment for pernicious placenta previa.

[Application of Low Dose Spiral CT in Diagnosing Impacted Teeth in Children and Adolescents].

UNLABELLED: [ABSTRACT] OBJECTIVE: To determine the value of low dose spiral CT scanning in diagnosing impacted teeth of children and adolescents. METHODS: A total of 153 children and adolescents with confirmed impacted teeth in West China Second University Hospital, Sichuan University were enrolled in this study. They were divided into 5 groups according to the different spiral CT scan parameters (tube current time product, scanning thickness and collimation value): Group A (n=30, 330 mAs, 6 X 0. 75 mm and 3. 0 mm), Group B (n=30, 140 mAs, 6 X 0. 75 mm and 3. 0 mm), Group C (n=30, 80 mAs, 6 X 0. 75 mm and 3. 0 mm), Group D (n=31, 80 mAs, 6 X 1. 50 mm and 5. 0 mm), and Group E (n=32, 50 mAs, 6 X 1. 50 mm and 5. 0 mm). There were no significant differences in general clinical features (P>0. 05) among the participants of the five groups. The phantoms were used to measure spatial resolution and contrast resolution of the scan images. Dose length product (DLP) was recorded during CT scanning for calculating effective dose (ED) of exposure. The quality of images was evaluated using a list of quality scoring criteria. RESULTS: (1) Under 330, 140, 80, 80 and 50 mAs, the images had a spatial resolution of 1.0 mm, with contrast resolution of 2. 0, 3. 0, 4. 5, 4. 5 and 6. 0 mm, respectively. (2) Significant differences in ED values were found among the five groups (F=1 064. 119, P=0. 000) and between every two of those groups (P<0. 05). Group E had the lowest ED (0. 19 mSv), 86. 52%, 67. 24%, 45. 71%, and 38. 71% lower than that in Group A, B, C and D, respectively (P<0. 05). (3) All of the five groups obtained an image quality score above 3, and no statistical differences appeared among the 5 groupl (F=1. 978, P>0. 05). The diagnostic results of the spiral CT were consistent with those of orthodontic surgery. CONCLUSION: Low dose spiral CT scanning can meet the image quality requirements for diagnosing impacted teeth, minimizing radiation exposure effectively.

Heuristic approximations for sound fields produced by spherical waves incident on locally and non-locally reacting planar surfaces.

The classic Weyl-van der Pol (WVDP) formula is a well-known asymptotic solution for accurately predicting sound fields above a locally reacting ground surface. However, the form of the WVDP formula is inadequate for predicting sound fields in the vicinity of non-locally reacting surfaces; a correction term is often required in the formula to provide accurate numerical solutions. Even with this correction, there is a singularity in the diffraction wave term when the source is located directly above or below the receiver. This paper explores a heuristic method to remove this singularity and suggests an analytical form comparable to the WVDP formula. This improved formula offers a physically interpretable solution and allows for accurate predictions of the total sound field above locally and non-locally reacting surfaces for all geometrical configurations.

Sound penetration into a hard-backed rigid porous layer: theory and experiments.

This study examines the sound field within a hard-backed rigid porous medium due to an airborne source. The total sound field can be approximated by two terms: A transmitted wave component arriving at the receiver directly through the porous interface, and a second transmitted wave component reflected from the rigid backing plane before reaching the receiver. These two components can be expressed in an integral form that is amenable to further analyses. A standard saddle path method is applied to evaluate the integral analytically, leading to a uniform asymptotic solution that allows the prediction of the sound field within the rigid porous medium. The validity of the asymptotic formula is verified by comparison with the numerical results computed by a more accurate wave-based numerical scheme. The asymptotic solution is shown to provide a convenient means of rapid and accurate computations of sound field within the rigid porous medium. The accuracy of the numerical solutions is further confirmed by comparison with indoor experimental results. The measurement data and theoretical predictions suggest that when the receiver is located near the bottom of the hard-backed layer, the reflection of the refracted wave gives rise to a significant contribution to the total sound field.

[Characteristics and Identification Priority Source of Heavy Metals Pollution in Farmland Soils in the Yellow River Basin].

Assessments of the soil environmental quality of farmland and pollution source apportionment are the foundation for ensuring national food security and agricultural sustainable development, as well as an important prerequisite for the pursuit to keep our lands clean. This study evaluated the characteristics of heavy metal pollution in farmland soils in the Yellow River Basin from 2000 to 2023, based on the data of heavy metal contents including As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, using the geo-accumulation index method. Source apportionment was conducted by employing a positive matrix factorization (PMF) model. The probabilistic health risks were evaluated by coupling Monte Carlo simulation with a human health risk assessment model, and priority pollution sources and elements were identified. The results showed that:① the average content of all heavy metals in farmland soils within the study area was lower than the screening values specified in the soil environment quality risk control standard for soil contamination of agriculture land (GB 15618-2018) (pH>7.5). However, the contents of Cd, As, and Zn in the samples exceeded their screening values, with percentages of 21.69%, 5.56%, and 1.23%, respectively, with Cd having the highest rate of exceedance. ② Hg and Cd were moderately polluted, Cu and Pb were slightly polluted, and the other elements were not polluted. ③ The main sources of heavy metals in farmland soil were traffic-industrial sources, natural-agricultural sources, industrial-natural sources, and agricultural-industrial sources, with contribution rates of 37.04%, 26.69%, 21.72%, and 14.55%, respectively. ④ Heavy metals in farmland soil posed carcinogenic health risks to adults and children but did not have non-carcinogenic risks; As and Cd were priority control elements for human health risks, and industrial-natural sources and agricultural-industrial sources were priority control sources in the study area.

[Pollution Characteristics and Risk Assessment of Heavy Metals in Surface Dusts and Surrounding Green Land Soils from Yellow River Custom Tourist Line in Lanzhou].

In order to investigate the contamination levels of dust and its surrounding green land soil heavy metal pollution and potential ecological and health risks in the scenic areas of urban waterfront parks, the gardens, squares, and theme parks of the Yellow River Custom Tourist Line in Lanzhou were selected as the research area, using 27 dust samples and 26 soil samples from its surrounding green lands. The contamination characteristics and potential ecological risks of eight heavy metals (Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb) were evaluated using the geo-accumulation index (Igeo), single-factor pollution index (Pi), Nemerow integrated pollution index (PN), and improved potential ecological risk index (RI). The human health risk assessment was also evaluated using the exposure risk model. The results showed that the average concentrations of the other heavy metals in the surface dusts were higher than the background values of Gansu Province and Lanzhou City, except that the As mean concentrations in the surface dusts and the surrounding green land soils were slightly lower than the Gansu Province background values. For its surrounding green land soils, the mean concentrations of the other heavy metals (Cu, Zn, Cd, Hg, and Pb) exceeded the soil background values of Gansu Province and Lanzhou City, whereas the Cr and Ni mean concentrations were lower than their corresponding soil background values of Gansu Province and Lanzhou City. The geo-accumulation and single-factor pollution indices demonstrated that a slight to moderate pollution of Cr, Cu, Zn, Cd, Hg, and Pb occurred in surface dusts, and Cu, Zn, Cd, Hg, and Pb appeared in varying degrees of contamination levels in its surrounding green land soils. The Nemerow integrated pollution index analysis manifested that the overall contamination status of the study areas was between slightly and heavily polluted. The potential ecological risk index suggested that Cd and Hg were recognized as significant pollutant elements and that the RI of the other heavy metals were all below 40, presenting slight ecological risk. The health risk assessment indicated that ingestion was the dominant exposure pathway for heavy metals from the surface dusts and the surrounding green land soils, and no carcinogenic and noncarcinogenic risks posed threats to adults and children.

[Spatial Distribution Characteristics and Source Analysis of Heavy Metals in Urban River Surface Sediments from the Lanzhou Reach of the Yellow River].

In order to investigate the contamination characteristics and potential sources of heavy metals from the urban river surface sediments in the Yellow River Basin, we selected the Lanzhou reach of the Yellow River as the object of investigation. A total of 46 surface sediment samples were collected along the Lanzhou reach of the Yellow River, and the contents of eight heavy metals, Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb, were determined by using inductively coupled plasma mass spectrometry and an atomic fluorescence spectrometer. Contamination indexes including single factor pollution index (Pi) and geo-accumulation index (Igeo), together with the sediment pollution index (SPI), were used to assess heavy metal pollution characteristics and ecological risk levels in the urban river surface sediments of the Lanzhou reach of the Yellow River. Pearson's correlation analysis (CA), positive matrix factorization (PMF), and principal component analysis/absolute principal component score (PCA/APCS) were jointly employed to quantitatively analyze pollution sources of heavy metals. The results showed that the mean concentrations of the majority of heavy metals exceeded their corresponding background values of Gansu Province and Lanzhou City with the exception of As, and the spatial distribution of high concentrations of heavy metals was mainly concentrated in the corner of the river. Based on the single factor pollution and geo-accumulation indexes of the eight heavy metals, in the Lanzhou reach of the Yellow River, Cr was the dominant pollution element in the urban river surface sediments, followed by Cd and Ni. Additionally, the SPI values for the eight heavy metals in the surface sediments ranged from 0.48 to 8.56, presenting natural to low ecological risk level. Furthermore, source apportionment revealed that a mixture source of industrial and agricultural activities (77.6%) was the largest contributor of Cr, Ni, Zn, As, Cd, and Pb in the urban river surface sediments, followed by natural sources (11.4%) and a mixed source of industrial and traffic activities (11%).

[Contamination Characteristics and Source Apportionment of Potentially Toxic Elements in Soil around the Coal-fired Power Plant Using APCS-MLR and PMF Models].

To investigate the characteristics and sources of potentially toxic elemental contamination in soils around the coal-fired power plant, we selected the soil around the Jingyuan power plant as the object of investigation. Thirty-six and 27 soil samples collected from the urban and farmland areas were analyzed for PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn), respectively. We employed the geoaccumulation index, single-factor pollution index, and improved Nemerow integrated pollution index to evaluate the contamination characteristics of PTEs, and combined correlation analysis with absolute principal component scores-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) receptor models were used to quantitatively analyze the pollution sources of PTEs. The results revealed that all the average concentrations of other soil metals around Jingyuan power plant exceeded their corresponding background values of Gansu Province, except for As, in agricultural soil, and Hg exhibited significant spatial non-homogeneity, and thus it was visibly affected by anthropogenic activities. The values of the single-factor pollution and geoaccumulation indices indicated that the soils of both sites were mainly contaminated with Cd, Cr, Ni, and Pb, and Hg contamination was reflected in wide areas for both sites. Additionally, the results of the improved Nemerow index demonstrated that the investigated soil was between moderately contaminated and heavily contaminated. Further, the comprehensive pollution degree of urban soil was higher than that of agricultural soil. Moreover, source apportionment revealed that PTEs in urban soil were derived from mixed sources of traffic activities and coal combustion, mixed sources of traffic activities and industrial and mining activities, and atmospheric deposition from industrial activities, with contribution rates of APCS-MLR of 35.2%, 25.1%, and 23.4%, respectively. The PMF contribution rates were 40.2%, 12.4%, and 47.7%, respectively. PTEs in agricultural soil were from one mixture source of industrial, mining, agricultural, and traffic sources, and the other mixed source was of traffic activities and coal combustion, with a APCS-MLR contribution rate of 40.3% and 35.9% and a contribution rate of PMF of 36.2% and 18.0%, respectively. In addition, another mixed source of agricultural activities and coal combustion was obtained using the PMF model, with a contribution rate of 48.5%.

Propagation of sound from a monopole source above an impedance-backed porous layer.

In this article, the propagation of sound from a monopole source above an impedance-backed porous layer is examined. The sound fields can be expressed in an integral form that is amenable to further analysis. A standard method of steepest descents is applied to evaluate the integral where the method of pole subtraction is needed to obtain a uniform asymptotic solution for the sound field above the plane surface. To obtain a numerical solution, the location of the pole was determined numerically by means of the Newton-Raphson method. Based on the pole location, the sound fields can then be calculated numerically. It has been demonstrated that the use of a plane wave reflection coefficient to calculate the sound fields is a special case of the asymptotic formula when the pole is located further away from the saddle point.

Efficient computation of the sound fields above a layered porous ground.

An efficient computation of sound fields due to a monopole source placed above a porous layer is presented. This paper examines an improved scheme whereby the steepest descent path is selected for the numerical evaluation of the Sommerfeld integral. Along the steepest descent path, a standard Gaussian-Hermite quadrature can be used to calculate the sound fields effectively. The suggested numerical scheme is accurate at all frequencies except in the very near field. The proposed method is more numerically efficient than other computational schemes, especially at long ranges and high source frequencies.

Efficacy and Safety of Bushen Huoxue Formula in Patients with Discogenic Low-Back Pain: A Double-Blind, Randomized, Placebo-Controlled Trial.

OBJECTIVE: To assess the efficacy and safety of Bushen Huoxue Formula (BSHXF) for the treatment of discogenic low-back pain (DLBP). METHODS: This was a parallel, double-blind, randomized, clinical trial performed between May 2019 and June 2020. Seventy patients were assigned by computerized random number table to the treatment group (lumbar traction and BSHXF, 35 cases) or the control group (lumbar traction and placebo, 35 cases). The patients received intervention for 3 weeks. Assessment was conducted before treatment and at week 1, 2, 3 during treatment. Primary outcome was the self-reported score of Oswestry Disability Index (ODI). Secondary outcomes included Visual Analog Scale (VAS), clinical efficacy rate by minimal clinically important difference (MCID) as well as lumbar tenderness, muscle tone and lumbar spine mobility. Adverse reactions were recorded. Follow-up was performed at 1 and 3 months after the end of treatment. RESULTS: In the treatment group, ODI score was significantly decreased compared with baseline (P<0.05) and the control group at 2- and 3- week treatment. Similarly, VAS score decreased compared with the baseline (P<0.05) and was lower than that in the control group at 2- and 3- week treatment (P<0.05). The clinical efficacy rate of the treatment group was higher than that of the control group after treatment [32.35% (11/34) vs. 3.13% (1/32), P<0.05). Moreover, the tenderness, and muscle tone, as well as the back extension and left flexion in lumbar spine mobility in the treatment group at 3-week treatment were significantly improved compared with the control group (P<0.05). Follow-up showed that at 1-month after treatment, the treatment group had better outcomes than the control group with regard to a total score of ODI and VAS scores, as well as clinical efficacy rate (all P<0.05). Moreover, VAS score was still significantly lower than the control group at 3-month follow-up (P<0.05). No adverse reactions were reported during the study. CONCLUSION: BSXHF combined with lumbar traction can significantly improve the clinical symptoms including pain intensity, functionality, muscle tone, and lumbar spine mobility in DLBP patients. (Registration No. ChiCTR1900027777).

Reduced nucleus accumbens functional connectivity in reward network and default mode network in patients with recurrent major depressive disorder.

The nucleus accumbens (NAc) is considered a hub of reward processing and a growing body of evidence has suggested its crucial role in the pathophysiology of major depressive disorder (MDD). However, inconsistent results have been reported by studies on reward network-focused resting-state functional MRI (rs-fMRI). In this study, we examined functional alterations of the NAc-based reward circuits in patients with MDD via meta- and mega-analysis. First, we performed a coordinated-based meta-analysis with a new SDM-PSI method for all up-to-date rs-fMRI studies that focused on the reward circuits of patients with MDD. Then, we tested the meta-analysis results in the REST-meta-MDD database which provided anonymous rs-fMRI data from 186 recurrent MDDs and 465 healthy controls. Decreased functional connectivity (FC) within the reward system in patients with recurrent MDD was the most robust finding in this study. We also found disrupted NAc FCs in the DMN in patients with recurrent MDD compared with healthy controls. Specifically, the combination of disrupted NAc FCs within the reward network could discriminate patients with recurrent MDD from healthy controls with an optimal accuracy of 74.7%. This study confirmed the critical role of decreased FC in the reward network in the neuropathology of MDD. Disrupted inter-network connectivity between the reward network and DMN may also have contributed to the neural mechanisms of MDD. These abnormalities have potential to serve as brain-based biomarkers for individual diagnosis to differentiate patients with recurrent MDD from healthy controls.

Fast asymptotic solutions for sound fields above and below a rigid porous ground.

The current study simultaneously addresses the problem of reflection and refraction of sound from a rigid porous ground surface. A more rigorous approach is used to derive more accurate asymptotic solutions that can be cast in a convenient form for ease of numerical implementations. The solutions provide means for rapid computations of the sound fields above and below the rigid porous ground. The improved asymptotic formulas for both situations agree well with numerical results obtained by other numerical schemes, which are more accurate but computationally more intensive. More importantly, the asymptotic solutions can be written in the well-known form of the Weyl-van der Pol formula, which provides a direct correlation between the reflected wave term for the sound field above the porous ground and the transmitted (refracted) wave term for the sound field below.

The Effect and the Mechanism of Comprehensive Treatment on the Ocular Surface and the Visual Quality of Online Teachers with a Mild-to-Moderate Dry Eye Condition During the Early Phase of Coronavirus Disease 2019.

OBJECTIVE: To investigate the effect of comprehensive treatment on ocular surface function and the visual quality of online teachers with a mild-to-moderate dry eye condition during the early phase of coronavirus disease 2019 (COVID-19). METHODS: Secondary school online teachers diagnosed with a mild-to-moderate dry eye disease in our outpatient clinic from February to May 2020 were enrolled in this retrospective cross-section study, and all patients received dry eye comprehensive treatment. A questionnaire survey on eye-use habits, visual quality and dry eye-related indicators was collected before and after treatment (2 and 4 weeks). The changes and the correlations between indicators before and after treatment were compared. RESULTS: A total of 30 patients (15 females and 15 males) were included. After comprehensive treatment, patients had significantly higher central tear meniscus height (TMH), non-invasive first tear film breakup time (NIBUTf) and non-invasive average tear film breakup time (NIBUTav) than those before with statistical significance (P < 0.05). Lower ocular surface disease index (OSDI) and Meibomian gland scores were observed after treatment with statistical significance (P < 0.05). Objective scatter index (OSI), modulation transfer function (MTF) cutoff, strehl ratio (SR), and tear film objective scatter index (TF-OSI) were significantly improved after treatment (P < 0.05). Besides, TF-OSI was positively correlated with the changes in OSDI, Meibomian gland score, eye-use duration and OSI with statistical significance (P < 0.05), while it was negatively correlated with NIBUTf, NIBUTav, the TMH of the central lower eyelid, SR, sleep duration, conjunctival congestion and the MTF cutoff (P < 0.05), respectively. No correlation between TF-OSI and ciliary congestion was found (P > 0.05). CONCLUSION: Comprehensive treatment could effectively improve the symptoms and visual quality of online teachers with a mild-to-moderate dry eye condition during the early stage of COVID-19 pandemic.

[Study on the biomechanical analysis and influencing factors study for the treatment of humeral epicondylitis by Bachuorounian manipulation].

OBJECTIVE: To quantitatively study the biomechanical parameters of Bachuorounian manipulation in the treatment of humeral epicondylitis, and discuss the effects of individual characteristics on the biomechanical parameters were discussed. METHODS: From July 2019 to February 2020, 40 patients with external humeral epicondylitis were selected, including 18 males and 22 females, ranging in age from 20 to 50 years old, with an average of (34.37±8.41) years old;and the course of disease ranged from 1 to 11 months, with a mean of (6.05±2.71) months. The biomechanical parameters of the elbow joint of the affected side were measured by using the biomechanical sensor. At thesame time, the individual characteristic parameters of patients were collected to analyze the influence of different individual characteristics of patients on biomechanical parameters. RESULTS: The results of mechanical analysis in each stage of the bachuorounian manipulation were as follows:the rolling back rotation force was (31.17±2.99) N;the buckling bending drawing force was (44.99±2.38) N;the rolling pre rotation force was (31.03±2.75) N;and stretching drawing force was (48.75±2.09) N. The correlation analysis between the parameters showed that there was a significant positive correlation between the buckling bending drawing force and the stretching drawing force parameters, and a significant positive correlation between the rolling force back-rotation force and the rolling pre-rotation force parameters. The multivariate linear regression analysis on the parameters of influencing factors and manipulative biomechanics showed that there was a significant correlation between body weight and rolling back-rotation force, significant correlation between elbow tenderness and the buckling bending drawing force, and significant correlation between disease duration and the stretching drawing force. CONCLUSION: The bachuorounian manipulation of humeral epicondylitis has a certain range of operating force. Manipulation of each stage has a correlation and systematic. The patient's weight, elbow tenderness and disease course are important factors affecting the bachuorounian manipulation.