Determination of 22 phospholipids in serum by ultra performance liquid chromatography-tandem mass spectrometry / 中华劳动卫生职业病杂志

Objective: To establish ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of 22 phospholipids in serum. Methods: In September 2022, Using synthetic non endogenous phospholipids as internal standard, phospholipids in serum were extracted by methanol-dichloromethane (2∶1, V/V) protein precipitation method. Chromatographic separation was achieved on an ACQUITY UPLC BEH shield RP18 column, and the mobile phase was methanol/water (5∶95, V/V) containing 10 mM ammonium formate and methanol. Detection was performed in multiple reaction monitoring mode with ion mode switching. And the method was applied by analyzing phospholipids in the serum of coal workers' pneumoconiosis patients. Results: The 22 phospholipids showed good linear relationships in their respective concentration ranges and the correlation coefficients were higher than 0.990. The spiked recoveries of the 22 phospholipids were 81.03%-121.63% at the three spiked levels. The intra-assay were less than 14.52%, and the inter-assay were less than 15.00%. Conclusion: The method with the advantages of simplicity, stability and high sensitivity, and it can be used for the analysis of phospholipids in serum.

[Clinical analysis of severe/critical 2019 novel coronavirus Omicron variant infection combined with atrial fibrillation].

OBJECTIVE: To investigate the clinical characteristics and prognosis of coronavirus disease 2019 (COVID-19) patients with Omicron variant combined with atrial fibrillation (AF). METHODS: From March 23, 2022 to May 15, 2022, 2 675 aged ≥ 50 years old COVID-19 patients with AF were admitted to Zhoupu Hospital, the designated hospital for COVID-19 in Shanghai. Patients were divided into mild symptoms group, normal group, and serious/critical group according to the symptoms. The clinical data, imaging examination and laboratory results and prognosis of the three group patients were compared. RESULTS: The median age of 2 675 COVID-19 patients was 69.0 (60.0, 81.0) years old, the incidence of AF was 5.05% (135/2 675), the age range of AF patients were from 55 to 101 years old, with a median age of 84.0 (74.0, 89.0), and the number of mild symptoms, normal, serious/critical patients were 68, 30, 37, respectively, including 9 of serious and 28 of critical patients. In the serious/critical patients, aged 55-75 years old accounted for 43.2%, the rate of 2019 novel coronavirus vaccination was 32.4%. The identified new-onset AF was the highest among the three groups, but the rate of persistent AF was the highest in the mild symptoms group (58.8%). The severe/critical group complicated with fever (29.7%), hepatic insufficiency (13.5%), renal insufficiency (46.0%), type 2 diabetes (46.0%), and heart failure were higher in NYHA classification [compared with the mild symptoms and normal group (score): 1.8±1.1 vs. 1.1±0.8, 1.2±0.7, respectively, all P < 0.05]. In term of laboratory examinations, C-reactive protein (CRP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were significantly higher in serious/critical patients compared to the mild symptoms and normal groups [CRP (mg/L): 27.2 (6.0, 60.8) vs. 7.6 (3.1, 19.3), 12.8 (4.9, 26.3), ALT (U/L): 31.3±15.4 vs. 15.4±9.3, 19.3±11.7, AST (U/L): 78.0±21.7 vs. 34.7±15.6, 38.1±24.4, all P < 0.05]. The hemoglobin (Hb) and albumin (ALB) levels were significantly lower than those in the mild symptoms and normal groups [Hb (g/L): 105.3±22.5 vs. 125.8±25.4, 123.0±20.4, ALB (g/L): 33.7±6.0 vs. 39.0±5.5 and 39.6±13.1, all P < 0.05]. In addition, MB isoenzyme of creatine kinase (CK-MB) was significantly higher in the serious/critical group than that in the mild symptoms group [µg/L: 2.5 (1.5, 3.4) vs. 2.2 (1.2, 2.8), P < 0.05]. In terms of the treatment, the percentage of antiplatelet agents and low-molecular heparin ratio compared among the three groups were statistically significant, with the serious/critical group using the lowest percentage of antiplatelet agents (27.0%) and a higher percentage of low-molecular heparin usage than that in mild symptoms group [81.1% (30/37) vs. 51.5% (35/68), P < 0.05]. In terms of prognosis, the mortality of patients with AF was 18.5% (25/135), all of whom were critical ill, including 32.0% (8/25) with cerebral embolism, pulmonary embolism and cerebral hemorrhage. Among them, 40.0% (10/25) died of multiple organ failure (40.0% combined with gastrointestinal hemorrhage), 20.0% (5/25) died of heart failure, and 12.0% (3/25) died of respiratory failure; while there were no death cases recorded in the mild symptoms, normal group and 9 serious patients. CONCLUSIONS: The serious/critical patients infected with COVID-19 Omicron variant with AF, have a worse prognosis and high mortality. Multiple organ failure, heart failure, sudden cardiac death, respiratory failure and embolic disease are the major causes of death.

Fidelity Mechanics: Analogues of the Four Thermodynamic Laws and Landauer's Principle.

Fidelity mechanics is formalized as a framework for investigating critical phenomena in quantum many-body systems. Fidelity temperature is introduced for quantifying quantum fluctuations, which, together with fidelity entropy and fidelity internal energy, constitute three basic state functions in fidelity mechanics, thus enabling us to formulate analogues of the four thermodynamic laws and Landauer's principle at zero temperature. Fidelity flows, which are irreversible, are defined and may be interpreted as an alternative form of renormalization group flows. Thus, fidelity mechanics offers a means to characterize both stable and unstable fixed points: divergent fidelity temperature for unstable fixed points and zero-fidelity temperature and (locally) maximal fidelity entropy for stable fixed points. In addition, fidelity entropy behaves differently at an unstable fixed point for topological phase transitions and at a stable fixed point for topological quantum states of matter. A detailed analysis of fidelity mechanical-state functions is presented for six fundamental models-the quantum spin-1/2 XY model, the transverse-field quantum Ising model in a longitudinal field, the quantum spin-1/2 XYZ model, the quantum spin-1/2 XXZ model in a magnetic field, the quantum spin-1 XYZ model, and the spin-1/2 Kitaev model on a honeycomb lattice for illustrative purposes. We also present an argument to justify why the thermodynamic, psychological/computational, and cosmological arrows of time should align with each other, with the psychological/computational arrow of time being singled out as a master arrow of time.

Prediction model based on machine learning for short- and long-term adverse events in left atrial appendage closure.

Background: At present, the prediction of adverse events (AE) had practical significance in clinic and the accuracy of AE prediction model after left atrial appendage closure (LAAC) needed to be improved. To identify a good prediction model based on machine learning for short- and long-term AE after LAAC. Methods: In this study, 869 patients were included from the Department of Cardiovascular Medicine of Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital during 2017 and 2021. Univariate and multivariate analyses were conducted for short-term AE after LAAC to determine possible risk factors related with AE. We compared 8 machine learning algorithms for prediction short-term AE, and XGBoost was found to have the best performance. In addition, Cox-regression was used for long-term AE to find out the risk factors and establish a prediction model. Results: In univariate and multivariate analysis, body mass index (BMI) [odds ratio (OR) =0.91], congestive heart failure, hypertension, age ≥75 years, diabetes, stroke2 attack (CHADS2) score (OR =0.49) and bleeding history or predisposition, labile international normalized ratio (INR), elderly, drug/alcohol usage (BLED) score (OR =1.71) were shown to be significant risk factors for short-term AE. The XGbosst algorithm was used to predict short-term AE based on 15 possible risk factors. For long-term AE, Cox regression was used for the prediction. The CHADS2 score [hazard ratio (HR) =1.43], hypertension (HR =2.18), age more than 75 (HR =0.49), diabetes (HR =0.57), BLED score (HR=0.28), stroke (HR =19.8), hepatopathy (HR =3.97), nephropathy (HR =2.93), INR instability (HR =4.18), drinking (HR =2.67), and drugs (HR =2.36) were significant risk factors for long-term AE. The XGBoost had a good receiver operating characteristic (ROC) curve and area under the curve (AUC) was 0.85. The accuracy of the XGBoost model stayed at nearly 0.95. Conclusions: In short- and long-term AE, CHADS2 score and BLED score were the most obvious risk factors. Several other risk factors also played roles in AE of LAAC. The incidence of long-term AE is under 15% and LAAC is effective and safe. The XGBoost model had good prediction accuracy and ROC curve.

[Chronic spontaneous urticaria treated with bloodletting therapy and auricular point sticking on the base of xuanfu theory: a randomized controlled trial].

OBJECTIVE: To compare the clinical therapeutic effect and the impacts on recurrence rate on chronic spontaneous urticaria (CSU) between the combined treatment of bloodletting therapy and auricular point sticking on the base of xuanfu theory and the oral solution of levocetirizine hydrochloride. METHODS: A total of 86 patients with CSU were randomized into an observation group (43 cases, 1 case dropped off) and a control group (43 cases, 3 cases dropped off). In the observation group, bloodletting therapy at Dazhui (GV 14), Feishu (BL 13), Geshu (BL 17) and Pishu (BL 20) was combined with auricular point sticking at lung (CO14), kidney (CO10), shenmen (TF4) and heart (CO15), etc. This combined treatment was given once every two days. In the control group, the oral solution of levocetirizine hydrochloride was prescribed, 10 mL each time, once daily. The treatment lasted for 4 weeks in the two groups. Before and after treatment, urticaria activity score 7 (UAS7), the score of dermatology life quality index (DLQI) and the levels of serum immune globulin E (IgE), interleukin 4 (IL-4) and interferon γ (IFN-γ) were compared in the patients between the two groups. The clinical therapeutic effect was evaluated in patients of the two groups and the recurrence rate was followed up 4, 8 and 12 weeks after treatment separately. RESULTS: After treatment, the scores of UAS7 and DLQI, as well as the levels of serum IgE and IL-4 were all reduced as compared with those before treatment in the two groups (P<0.05), and the level of serum IFN-γ was increased (P<0.05). The total effective rate was 83.3% (35/42) in the observation group and was 85.0% (34/40) in the control group. There was no statistical significance for the difference in the clinical therapeutic effect between the two groups (P>0.05). Eight and 12 weeks after treatment, the recurrence rates were 21.1% (4/19) and 26.3% (5/19) in the observation group, lower than 55.0% (11/20) and 65.0% (13/20) in the control group, respectively (P<0.05). CONCLUSION: The combined therapy of bloodletting and auricular point sticking on the base of xuanfu theory relieves the clinical symptoms, regulates the levels of serum IgE, IL-4 and IFN-γ and improves the quality of life in the patients with CSU. The clinical therapeutic effect of this combined treatment is similar to the oral solution of levocetirizine hydrochloride. But, the recurrence rate of the combined treatment of bloodletting and auricular point sticking is lower and its long-term curative effect is better.

Chronic spontaneous urticaria treated with bloodletting therapy and auricular point sticking on the base of xuanfu theory: a randomized controlled trial / 中国针灸

OBJECTIVE@#To compare the clinical therapeutic effect and the impacts on recurrence rate on chronic spontaneous urticaria (CSU) between the combined treatment of bloodletting therapy and auricular point sticking on the base of xuanfu theory and the oral solution of levocetirizine hydrochloride.@*METHODS@#A total of 86 patients with CSU were randomized into an observation group (43 cases, 1 case dropped off) and a control group (43 cases, 3 cases dropped off). In the observation group, bloodletting therapy at Dazhui (GV 14), Feishu (BL 13), Geshu (BL 17) and Pishu (BL 20) was combined with auricular point sticking at lung (CO14), kidney (CO10), shenmen (TF4) and heart (CO15), etc. This combined treatment was given once every two days. In the control group, the oral solution of levocetirizine hydrochloride was prescribed, 10 mL each time, once daily. The treatment lasted for 4 weeks in the two groups. Before and after treatment, urticaria activity score 7 (UAS7), the score of dermatology life quality index (DLQI) and the levels of serum immune globulin E (IgE), interleukin 4 (IL-4) and interferon γ (IFN-γ) were compared in the patients between the two groups. The clinical therapeutic effect was evaluated in patients of the two groups and the recurrence rate was followed up 4, 8 and 12 weeks after treatment separately.@*RESULTS@#After treatment, the scores of UAS7 and DLQI, as well as the levels of serum IgE and IL-4 were all reduced as compared with those before treatment in the two groups (P<0.05), and the level of serum IFN-γ was increased (P<0.05). The total effective rate was 83.3% (35/42) in the observation group and was 85.0% (34/40) in the control group. There was no statistical significance for the difference in the clinical therapeutic effect between the two groups (P>0.05). Eight and 12 weeks after treatment, the recurrence rates were 21.1% (4/19) and 26.3% (5/19) in the observation group, lower than 55.0% (11/20) and 65.0% (13/20) in the control group, respectively (P<0.05).@*CONCLUSION@#The combined therapy of bloodletting and auricular point sticking on the base of xuanfu theory relieves the clinical symptoms, regulates the levels of serum IgE, IL-4 and IFN-γ and improves the quality of life in the patients with CSU. The clinical therapeutic effect of this combined treatment is similar to the oral solution of levocetirizine hydrochloride. But, the recurrence rate of the combined treatment of bloodletting and auricular point sticking is lower and its long-term curative effect is better.

Interpretation of Update: Standardized CT/HRCT Classification of Occupational and Environmental Thoracic Diseases in Germany published in 2014 / 中国职业医学

@#Imaging diagnosis is one of the main bases for the diagnosis of occupational pneumoconiosis. At present the - diagnosis of occupational pneumoconiosis is mainly based on high kV X ray chest radiography or chest digital radiography. With （ ） ， （ ） the wide application of computed tomography CT in occupational lung diseases high resolution CT HRCT is increasingly Update： Standardized CT/HRCT Classification of Occupational valuable in the diagnosis of occupational pneumoconiosis. The and Environmental Thoracic Diseases in Germany， ， published in 2014 is the latest and highly reliable standard. The standard - - - recommends the use of low dose HRCT scanning regimens and whole lung thin layer volumetric scanning with a thickness of - ， ， 1.0 mm and high resolution reconstruction which classify CT image quality into four levels and describes methods for （ ， classification and quantitative recording of CT manifestations of lung lesions including round opacities irregular and/or linear ， ， ， ， ） opacities ground glass opacity honeycombing emphysema and large opacities and pleural lesions. It is beneficial for ， ， ， epidemiological research early screening diagnosis and differential diagnosis treatment and prognosis of occupational ， pneumoconiosis as well as the comparison of international data related to occupational pneumoconiosis.

Interpretation of Update: Standardized CT/HRCT Classification of Occupational and Environmental Thoracic Diseases in Germany published in 2014 / 中国职业医学

@#Imaging diagnosis is one of the main bases for the diagnosis of occupational pneumoconiosis. At present the - diagnosis of occupational pneumoconiosis is mainly based on high kV X ray chest radiography or chest digital radiography. With （ ） ， （ ） the wide application of computed tomography CT in occupational lung diseases high resolution CT HRCT is increasingly Update： Standardized CT/HRCT Classification of Occupational valuable in the diagnosis of occupational pneumoconiosis. The and Environmental Thoracic Diseases in Germany， ， published in 2014 is the latest and highly reliable standard. The standard - - - recommends the use of low dose HRCT scanning regimens and whole lung thin layer volumetric scanning with a thickness of - ， ， 1.0 mm and high resolution reconstruction which classify CT image quality into four levels and describes methods for （ ， classification and quantitative recording of CT manifestations of lung lesions including round opacities irregular and/or linear ， ， ， ， ） opacities ground glass opacity honeycombing emphysema and large opacities and pleural lesions. It is beneficial for ， ， ， epidemiological research early screening diagnosis and differential diagnosis treatment and prognosis of occupational ， pneumoconiosis as well as the comparison of international data related to occupational pneumoconiosis.

Critical exponents of block-block mutual information in one-dimensional infinite lattice systems.

We study the mutual information between two lattice blocks in terms of von Neumann entropies for one-dimensional infinite lattice systems. Quantum q-state Potts model and transverse-field spin-1/2 XY model are considered numerically by using the infinite matrix product state approach. As a system parameter varies, block-block mutual information exhibit singular behaviors that enable us to identify the critical points for the quantum phase transitions. As happens with von Neumann entanglement entropy of single block, at critical points, block-block mutual information for two adjacent blocks show a logarithmic leading behavior with increasing the size of the blocks, which yields the central charge c of the underlying conformal field theory, as it should be. It seems that two disjoint blocks show a similar logarithmic growth of the mutual information as a characteristic property of critical systems but the proportional coefficients of the logarithmic term are very different from the central charges. As the separation between the two lattice blocks increases, the mutual information reveals a consistent power-law decaying behavior for various truncation dimensions and lattice-block sizes. The critical exponent of block-block mutual information in the thermodynamic limit is estimated by extrapolating the exponents of power-law decaying regions for finite truncation dimensions. For a given lattice-block size ℓ, the critical exponents for the same universality classes seem to have very close values each other. Whereas the critical exponents have different values to a degree of distinction for the different universality classes. As the lattice-block size becomes bigger, the critical exponent becomes smaller. We discuss a relation between the exponents of block-block mutual information and correlation with the Shatten one-norm of block-block correlation.

Seroprevalence of IgM and IgG Antibodies against SARS-CoV-2 in Asymptomatic People in Wuhan: Data from a General Hospital Near South China Seafood Wholesale Market during March to April in 2020.

The aim of this study was to estimate the seroprevalence of immunoglobulin M (IgM) and G (IgG) antibodies against SARS-CoV-2 in asymptomatic people in Wuhan. This was a cross-sectional study, which enrolled 18,712 asymptomatic participants from 154 work units in Wuhan. Pearson Chi-square test, t-test, and Mann-Whitney test were used to compare the standardized seroprevalence of IgG and IgM for age and gender between different groups. The results indicated the standardized seroprevalence of IgG and IgM showed a downward trend and was significantly higher among females than males. Besides, different geographic areas and workplaces had different seroprevalence of IgG among asymptomatic people, and the number of abnormalities in CT imaging were higher in IgG antibody-positive cases than IgG-negative cases. We hope these findings can provide references for herd immunity investigation and provide basis for vaccine development.

Analysis of Health Service Utilization and its Influencing Factors among Patients with Pneumoconiosis in China.

Pneumoconiosis, an interstitial lung disease that occurs from breathing in certain kinds of damaging dust particles, is a major occupational disease in China. Patients diagnosed with occupational pneumoconiosis can avail of free medical treatment, whereas patients without a diagnosis of occupational diseases cannot not claim free medical treatment in most provinces from the government before 2019. This study aimed to analyze the priority of medical facility selection and its influencing factors among patients with pneumoconiosis. A total of 1,037 patients with pneumoconiosis from nine provinces in China were investigated. The health service institutions most frequently selected by the patients were county-level hospitals (37.5%). The main reason for the choice was these hospitals' close distance to the patients' homes (47.3%). The factors for the choice of health care institutions were living in the eastern region ( OR = 2.91), living in rural areas ( OR = 2.10), silicosis diagnosis ( OR = 2.44), employment in private enterprises ( OR = 2.91), smoking ( OR = 2.69), and quit smoking ( OR = 3.98). The diagnosis, treatment, and rehabilitation therapy of pneumoconiosis should be enhanced in primary medical institutions.

Seroprevalence of IgM and IgG Antibodies against SARS-CoV-2 in Asymptomatic People in Wuhan: Data from a General Hospital Near South China Seafood Wholesale Market during March to April in 2020 / 生物医学与环境科学（英文）

The aim of this study was to estimate the seroprevalence of immunoglobulin M (IgM) and G (IgG) antibodies against SARS-CoV-2 in asymptomatic people in Wuhan. This was a cross-sectional study, which enrolled 18,712 asymptomatic participants from 154 work units in Wuhan. Pearson Chi-square test,

Projects status analysis of occupational respiratory diseases funded by the National Natural Science Foundation of China from 1987 to 2018 / 中国职业医学

OBJECTIVE: To analyze the funding status of the National Natural Science Fund(NNSF) in the field of occupational respiratory disease(ORD) research in China. METHODS: Through the NNSF Committee Science Foundation sharing service network database, we collected the information of funded projects in the field of ORD research in China from 1987 to 2018, and analyzed the funding expenditure, funding categories, supporting units and research contents. RESULTS: A total of 106 NNSF funded projects were obtained in the research field of ORD in China in the period 1987-2018, and the total amount of funding was 37.945 million yuan. The number of funded projects, the average and the total amounts of fundings showed an increasing trend year by year(all P<0.05). The main types of funded projects were general projects and Youth Science Foundation projects(97.2%). The funded projects and funds were mainly concentrated in colleges and universities, accounting for 79.2% and 83.4% respectively. Beijing(29 items, 27.4%), Hebei(13 items, 12.3%) and Jiangsu(11 items, 10.4%) were the top three provinces and municipalities in the number of funded projects. Silicosis, pulmonary fibrosis, quartz, alveolar macrophages and acute lung injury were the top five keywords of funded project items, and the research types mainly focused on the mechanism of diseases. CONCLUSION: The NNSF funding is imbalanced in the types of funding, supporting units, and regional distribution on ORD research field in China. It is suggested that the funding structure of NNSF should be optimized, interdisciplinary research should be encouraged and expanded, and cooperation among different institutions and regions should be promoted.

Analysis of Health Service Utilization and its Influencing Factors among Patients with Pneumoconiosis in China / 生物医学与环境科学（英文）

Pneumoconiosis, an interstitial lung disease that occurs from breathing in certain kinds of damaging dust particles, is a major occupational disease in China. Patients diagnosed with occupational pneumoconiosis can avail of free medical treatment, whereas patients without a diagnosis of occupational diseases cannot not claim free medical treatment in most provinces from the government before 2019. This study aimed to analyze the priority of medical facility selection and its influencing factors among patients with pneumoconiosis. A total of 1,037 patients with pneumoconiosis from nine provinces in China were investigated. The health service institutions most frequently selected by the patients were county-level hospitals (37.5%). The main reason for the choice was these hospitals' close distance to the patients' homes (47.3%). The factors for the choice of health care institutions were living in the eastern region (

Tailoring Artificial Mode to Enable Cofired Integration of Shear-type Piezoelectric Devices.

Low-temperature cofired ceramic technology is the prerequisite for producing advanced integrated piezoelectric devices that enable modern micro-electromechanical systems because of merits such as high level of compactness and ultralow drive voltage. However, piezoceramic structure with shear-type outputs, as a most fundamental functional electronic element, has never been successfully fabricated into multilayer form by the cofired method for decades. Technical manufacture requirements of parallel applied electric fields and polarization are theoretically incompatible with intrinsically orthogonal orientations in naturally occurring shear modes. Herein, inspired by the philosophy of building metamaterial from identical unit cells, an artificial prototype device with distinctive patterned electrodes and arrayed piezoceramic subunits is designed and fabricated, which is proved to perfectly generate synthetic face shear deformation. At the same drive voltage, an enhanced shear-type displacement output by over an order of magnitude is observed beyond previous d15-mode bulk elements. Further results of guided wave-based structural health monitoring and force sensing confirm that the methodology wipes out a tough piezoelectric technique barrier, and promises to fundamentally enlighten advances of integrated shear-mode piezoelectric devices for augmented actuation, sensing, and transduction applications.

A high-sensitivity and long-distance structural health monitoring system based on bidirectional SH wave phased array.

When estimating a structural health monitoring (SHM) system, its defect sensitivity and area/distance coverage are most important factors. For commonly used guided wave sparse array system, it usually requires a reference state as the baseline which is not available in many cases. In comparison, phased array technique typically does not need the baseline in simple structures and it had been successfully used in nondestructive testing (NDT). However, currently developed phased array systems employed omni-directional transducers routinely, where the wave energy is distributed equally along all directions thus it is not favorable for long-distance detection. In this work, bidirectional piezoelectric transducers were used to form a linear phased array system, which can generate/receive shear horizontal (SH) wave with high energy concentration. Firstly, the configuration of the employed transducer composed by antiparallel d15 piezoelectric strips (APS) was presented. Then the total focusing method (TFM) employed for defect detection was introduced. After validating the radiation pattern of SH wave generated by the APS, the properties of beam steering for the proposed phased array was investigated. Finally, experiments were carried out to validate its performance in detection of various defects. Results indicated that even for a 1 mm through-thickness hole 700 mm away, the proposed phased array system can still detect it accurately, which is much better than previous SHM systems. Dual defects including a crack and a hole can also be clearly detected without baseline. The high-sensitivity of the proposed system was attributed to the employed bidirectional transducer which can generate non-dispersive SH0 wave with high energy concentration. This proposed SH wave phased array system will provide a high-performance SHM method for plate-like structures.

Long-distance structural health monitoring of buried pipes using pitch-catch T(0,1) wave piezoelectric ring array transducers.

In modern industries, long-distance guided wave inspection has been routinely used for various types of pipelines. The usage of T(0,1) wave is always of great interests since it is the only non-dispersive wave mode in pipes. In this work, a pair of pitch-catch piezoelectric ring arrays were proposed for long-distance structural health monitoring (SHM) of buried pipes. Firstly, the working principle of the proposed transducer was introduced. Next, the performances of thickness-shear (d15) and face-shear (d24) modes based piezoelectric ring transducers in T(0,1) wave generation and reception were comparatively tested. It was found that at most frequencies, it is best to employ the d15 ring as the exciter and the d24 ring as the receiver. Then, the signal-to-noise ratio (SNR) of the generated T(0,1) wave and its attenuation in pipes with different coating conditions were investigated to estimate the detectable distance using the proposed transducer. Results showed that after applying acoustical isolation layer on pipes, the proposed ring transducers can inspect buried pipes over 20 m. Finally, the performance of the ring transducers in defect detection was validated. This work is expected to provide a promising solution to long-distance SHM of buried pipes.

Quick and repeatable shear modulus measurement based on torsional resonance using a piezoelectric torsional transducer.

Shear modulus is one of the fundamental mechanical properties of materials, while its quick and accurate measurement is still a challenge. Here we proposed a method for shear modulus measurement based on torsional resonance using a piezoelectric torsional transducer bonded on a cylindrical specimen. Firstly, the torsional transducer was introduced which consists of two thickness poled, thickness shear (d15) piezoelectric half-rings. Secondly, the equivalent circuit of the transducer-cylindrical specimen system is derived and the shear modulus can be explicitly obtained using the torsional resonance frequency. The internal friction can also be obtained, which is calculated by using an approximate formula. Then, shear modulus and internal friction measurement on four materials including 1045 steel, 6061 aluminum, quartz glass and PMMA were conducted. Results indicate that all the measured shear moduli are consistent with the reference values in literatures. The repeatable error in shear modulus measurement is within 0.2%, which is very desirable. Finally, shear modulus measurement scheme under high (or low) temperature is proposed using a frequency-match quartz glass bar as the thermal insulator. Measurement results on the 6061 aluminum indicates that from room temperature to 500 °C, the shear modulus decreases from 26.8 GPa to 16.6GPa. The proposed method is very reliable and quite convenient, which can be widely used in near future.

Optimized cutoff maternal age for adverse obstetrical outcomes: a multicenter retrospective cohort study in Urban China during 2011 to 2012.

BACKGROUND: China's two-child policy has led to a trend of aging in pregnancy which was associated with adverse outcomes. This study aimed to identify the clinically cutoff maternal age for adverse obstetric outcomes in China. METHODS: This secondary analysis of a multicenter retrospective cohort study included data of childbearing women from 39 hospitals collected in urban China during 2011 to 2012. Logistic regression was used to assess the adjusted odds ratios (aOR) of adverse outcomes in different age groups in comparison to women aged 20 to 24 years. The adjustments included the location of the hospital, educational level, and residence status. Clinically cutoff age was defined as the age above which the aOR continuously become both statistically (P < 0.05) and clinically (aOR > 2) significant. RESULTS: Overall, 108,059 women were recruited. In primiparae, clinically cutoff maternal ages for gestational diabetes (aOR: 2.136, 95% confidence interval [CI]: 1.856-2.458, P < 0.001), placenta previa (aOR: 2.400, 95% CI: 1.863-3.090, P < 0.001), cesarean section (aOR: 2.511, 95% CI: 2.341-2.694, P < 0.001), hypertensive disorder (aOR: 2.122, 95% CI: 1.753-2.569, P < 0.001), post-partum hemorrhage (aOR: 2.129, 95% CI: 1.334-3.397, P < 0.001), and low birth weight (aOR: 2.174, 95% CI: 1.615-2.927, P < 0.001) were 27, 31, 33, 37, 41, and 41 years, respectively. In multiparae, clinically cutoff ages for gestational diabetes (aOR: 2.977, 95%CI: 1.808-4.904, P < 0.001), hypertensive disorder (aOR: 2.555, 95% CI: 1.836-3.554, P < 0.001), cesarean section (aOR: 2.224, 95% CI: 1.952-2.534, P < 0.001), post-partum hemorrhage (aOR: 2.140, 95% CI: 1.472-3.110, P < 0.001), placenta previa (aOR: 2.272, 95% CI: 1.375-3.756, P < 0.001), macrosomia (aOR: 2.215, 95% CI: 1.552-3.161, P < 0.001), and neonatal asphyxia (aOR: 2.132, 95% CI: 1.461-3.110, P < 0.001) were 29, 31, 33, 35, 35, 41, and 41 years, respectively. CONCLUSIONS: Early cutoff ages for gestational diabetes and cesarean section highlight a reasonable childbearing age in urban China. The various optimized cutoff ages for different adverse pregnancy outcomes should be carefully considered in childbearing women.