Preparation and Mechanism of Toughened and Flame-Retardant Bio-Based Polylactic Acid Composites.

As a biodegradable thermoplastic, polylactic acid (PLA) shows great potential to replace petroleum-based plastics. Nevertheless, the flammability and brittleness of PLA seriously limits its use in emerging applications. This work is focused on simultaneously improving the flame-retardancy and toughness of PLA at a low additive load via a simple strategy. The PLA/MKF/NTPA biocomposites were prepared by incorporating alkali-treated, lightweight, renewable kapok fiber (MKF) and high-efficiency, phosphorus-nitrogenous flame retardant (NTPA) into the PLA matrix based on the extrusion-injection molding method. When the additive loads of MKF and NTPA were 0.5 and 3.0 wt%, respectively, the PLA/MKF/NTPA biocomposites (PLA3.0) achieved a rating of UL-94 V-0 with an LOI value of 28.3%, and its impact strength (4.43 kJ·m-2) was improved by 18.8% compared to that of pure PLA. Moreover, the cone calorimetry results confirmed a 9.7% reduction in the average effective heat of combustion (av-EHC) and a 0.5-fold increase in the flame retardancy index (FRI) compared to the neat PLA. NTPA not only exerted a gas-phase flame-retardant role, but also a condensed-phase barrier effect during the combustion process of the PLA/MKF/NTPA biocomposites. Moreover, MKF acted as an energy absorber to enhance the toughness of the PLA/MKF/NTPA biocomposites. This work provides a simple way to prepare PLA biocomposites with excellent flame-retardancy and toughness at a low additive load, which is of great importance for expanding the application range of PLA biocomposites.

Study on exercise muscle fatigue based on sEMG and ECG data fusion and temporal convolutional network.

BACKGROUND: Muscle fatigue is a crucial indicator to determine whether training is in place and to protect trainers. PURPOSE: To make full use of morphological information of surface EMG and ECG signals in the time domain, a new idea and method for the fatigue assessment of exercise muscles based on data fusion is proposed in this paper. METHODS: sEMG and ECG time series with the same length were obtained by signal preprocessing and sequence normalization, feature extraction of sequence tenses was realized by a deep learning network based on sequential convolution and signal fusion model of muscle fatigue evaluation was established by D-S evidence theory. EXPERIMENT: Thirty volunteers were recruited and divided into three groups. ECG signals and sEMG signals at the biceps brachii of the right upper limb were monitored in a 20-minute exercise cycle. RESULTS: The prediction result of TCN based on time domain signal is better than the commonly used KNN and SVM recognition algorithm, and the recognition accuracy of relaxed, excessive and fatigue by D-S fusion was 89%, 86%, 88.5%. The accuracy was 0.9055, 0.9494 and 0.9269, respectively. The recall rates of the three conditions were 0.9303, 0.9570 and 0.9435. The F-score of the three conditions was 0.8911, 0.8764 and 0.8837, respectively. CONCLUSION: Based on time series and time series convolutional network, sEMG and ECG fusion of motor muscle recognition method can better distinguish different state information and has certain practical value in the fields of muscle evaluation, clinical diagnosis, wearable devices and so on.

Management of acute exacerbation of chronic obstructive pulmonary disease under a tiered medical system in China.

BACKGROUND: The Chinese government has promoted the 'tiered medical services' policy in which diseases are classified by severity, mode of onset and difficulty of treatment since 2015 to optimize medical resources. We evaluated the diagnosis and treatment of acute exacerbation (AE) of chronic obstructive pulmonary disease (AECOPD) under the tiered system. METHODS: We conducted a cross-sectional study. COPD characteristics and treatments were compared among hospitals in different tiers. Associations were examined by univariate and multivariable logistic regression analysis. In addition, multivariate logistic regression was performed to identify the possible influencing factors of antibiotics, glucocorticoids and anticoagulant usages. RESULTS: Eligible COPD patients (n = 432) were consecutively recruited from eight hospitals in different tiers in China. Patients in the countryside preferred the community hospitals, whereas patients in cities preferred second-tier and teaching hospitals when they suffer from AECOPD. It indicates most COPD patients are likely to treat their disease locally. The severity of COPD AE increased with tiers of hospitals (p < 0.001). However, our results clearly show that most community hospitals can only deal with mild exacerbation of COPD. Approximately 90% of AE patients received antibiotics. We speculated that antibiotics abuse might exist in the three tiers of hospitals. Multivariate analysis demonstrated that long-term antibiotics usage (⩾14 days) was associated with moderate exacerbation [odds ratio (OR): 5.295, 95% confidence intervals (CI) 2.248-12.473, p < 0.001], radiographic progression (OR: 2.176, 95% CI: 1.047-4.522, p = 0.037), positive sputum etiology (OR: 3.073, 95% CI: 1.477-6.394, p = 0.003) and increased white blood cells (OR: 2.470, 95% CI: 1.190-5.126, p = 0.015). The proportion of glucocorticoids increased with the hospital hierarchy (18.6% versus 45.6% versus 69.2%, p < 0.001). The proportions of severe cases in the second-tier hospitals were 26.9%; however, non-invasive positive pressure ventilation (NPPV) rate was only 14.7%. Anticoagulant is not commonly used in AECOPD, and the community hospitals had the lowest proportion of anticoagulation regimen (1.7% versus 14.3% versus 20.5%, p = 0.002). CONCLUSIONS: The 'tiered medical services' policy in AECOPD management has been unsatisfactory in the past years. Irrational treatment strategies in different hospitals were still found when comparing with international guideline. Further reform of the policy is still needed to optimize the management of AECOPD in China.

Stable Chronic Obstructive Pulmonary Disease (COPD) Management Under a Tiered Medical System in China.

BACKGROUND: Early diagnosis and proper management of a large number of chronic obstructive pulmonary disease (COPD) patients are great challenges for the Chinese health care system. Although tiered medical services have been promoted by the Chinese government since 2015, they have not been ideally implemented for COPD diagnosis and management. PATIENTS AND METHODS: We designed a cross-sectional study. Eligible COPD patients (n = 648) and physicians (n = 161) were consecutively recruited from 8 hospitals in different tiers in China. COPD characteristics and treatments were compared among hospitals in different tiers. Multivariate logistic regression was performed to identify risk factors associated with airflow limitation, symptoms and acute exacerbation. RESULTS: The PFT rate at first diagnosis was 99%, 69.4% and 29.9% in teaching, second-tier and community hospitals (P < 0.001). Only approximately 10.9%, 1.7% and 9.6% and 21.8%, 6.9% and 32% of COPD patients received influenza or pneumococcal vaccines (P < 0.001). The proportion of patients who did not use inhaled drugs or had irregular inhalation was 2%, 24.6% and 78.8% (P < 0.001). Education level (RR-1 = -41.26%, P = 0.007), FEV1%pred (RR-1 = -2.76%, P < 0.001), and influenza vaccination in the last year (RR-1 = -64.53%, P = 0.006) were all negatively correlated with COPD acute exacerbation (AE). COPD duration (RR-1 = 131.73%, P = 0.009), AE (RR-1 = 151.39%, P < 0.001), and COPD Assessment Test (CAT) scores (RR-1 = 3.82%, P = 0.019) were all positively correlated with COPD airflow limitation severity. CONCLUSION: Differences exist in the diagnosis, treatment and management of COPD among different tiers of hospitals in China. Teaching hospitals can manage COPD patients relatively well. There are still some gaps compared with developed countries.

Transcriptome profiling identifies immune response genes against porcine reproductive and respiratory syndrome virus and Haemophilus parasuis co-infection in the lungs of piglets.

BACKGROUND: Co-infections of the porcine reproductive and respiratory syndrome virus (PRRSV) and the Haemophilus parasuis (HPS) are severe in Chinese pigs, but the immune response genes against co-infected with 2 pathogens in the lungs have not been reported. OBJECTIVES: To understand the effect of PRRSV and/or HPS infection on the genes expression associated with lung immune function. METHODS: The expression of the immune-related genes was analyzed using RNA-sequencing and bioinformatics. Differentially expressed genes (DEGs) were detected and identified by quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC) and western blotting assays. RESULTS: All experimental pigs showed clinical symptoms and lung lesions. RNA-seq analysis showed that 922 DEGs in co-challenged pigs were more than in the HPS group (709 DEGs) and the PRRSV group (676 DEGs). Eleven DEGs validated by qRT-PCR were consistent with the RNA sequencing results. Eleven common Kyoto Encyclopedia of Genes and Genomes pathways related to infection and immune were found in single-infected and co-challenged pigs, including autophagy, cytokine-cytokine receptor interaction, and antigen processing and presentation, involving different DEGs. A model of immune response to infection with PRRSV and HPS was predicted among the DEGs in the co-challenged pigs. Dual oxidase 1 (DUOX1) and interleukin-21 (IL21) were detected by IHC and western blot and showed significant differences between the co-challenged pigs and the controls. CONCLUSIONS: These findings elucidated the transcriptome changes in the lungs after PRRSV and/or HPS infections, providing ideas for further study to inhibit ROS production and promote pulmonary fibrosis caused by co-challenging with PRRSV and HPS.

Psychological Impact During the First Outbreak of COVID-19 on Frontline Health Care Workers in Shanghai.

Background: The COVID-19 pandemic is a significant health threat. Health care worker (HCWs) are at a significant risk of infection which may cause high levels of psychological distress. The aim of this study was to investigate the psychological impact of the COVID-19 on HCWs and factors which were associated with these stresses during the first outbreak in Shanghai. Methods: Between February 9 and 21, 2020, a total of 3,114 frontline HCWs from 26 hospitals in Shanghai completed an online survey. The questionnaire included questions on their sociodemographic characteristics, 15 stress-related questions, and General Health Questionnaire-12 (GHQ-12). Exploratory factor analysis was applied to the 15 stress-related questions which produced four distinct factors for evaluation. Multiple linear regression models were performed to explore the association of personal characteristics with each score of the four factors. Binary logistic analysis was used to explain the association of personal characteristics and these four factors with the GHQ-12. Results: There were 2,691 valid surveys received. The prevalence of emotional distress (defined as GHQ-12 ≥ 12) was noted in 47.7% (95%CI:45.7-49.6%) HCWs. Females (OR = 1.43, 95%CI:1.09-1.86) were more likely to have a psychological distress than males. However, HCWs who work in secondary hospitals (OR = 0.71, 95% CI:0.58-0.87) or had a no contact history (OR = 0.45, 95%CI: 0.35-0.58) were less likely to suffer psychological distress. HCWs who were nurses, married, and had a known contact history were highly likely to have anxiety. HCWs working at tertiary hospitals felt an elevated anxiety regarding the infection, a lack of knowledge, and less protected compared to those who worked at secondary hospitals. Conclusions: Our study shows that the frontline HCWs had a significant psychosocial distress during the COVID-19 outbreak in Shanghai. HCWs felt a lack of knowledge and had feelings of being not protected. It is necessary for hospitals and governments to provide additional trainings and psychological counseling to support the first-line HCWs.

Implementation of Online Hospitals and Factors Influencing the Adoption of Mobile Medical Services in China: Cross-Sectional Survey Study.

BACKGROUND: Online hospitals are part of an innovative model that allows China to explore telemedicine services based on national conditions with large populations, uneven distribution of medical resources, and lack of quality medical resources, especially among residents needing to be protected from COVID-19 infection. OBJECTIVE: In this study, we built a hypothesis model based on the Unified Theory of Acceptance and Use of Technology (UTAUT) in order to analyze the factors that may influence patients' willingness to use mobile medical services. This research was designed to assist in the development of mobile medical services. Residents who do not live in urban areas and cannot access medical assistance would greatly benefit from this research, as they could immediately go to the online hospital when needed. METHODS: A cross-sectional study based at the West China Hospital, Sichuan University, was conducted in July 2020. A total of 407 respondents, 18 to 59 years old, in Western China were recruited by convenience sampling. We also conducted an empirical test for the hypothesis model and applied structural equation modeling to estimate the significance of path coefficients so that we could better understand the influencing factors. RESULTS: Out of 407 respondents, 95 (23.3%) were aware of online hospitals, while 312 (76.7%) indicated that they have never heard of online hospitals before. Gender (P=.048) and education level (P=.04) affected people's willingness to use online hospitals, and both of these factors promoted the use of online hospitals (odds ratio [OR] 2.844, 95% CI 1.010-8.003, and OR 2.187, 95% CI 1.031-4.636, respectively). According to structural equation modeling, the results of the path coefficient analysis indicated that performance expectancy, effort expectancy, and facilitating conditions have positive effects on patients' willingness to use online hospitals. CONCLUSIONS: The goal of our research was to determine the factors that influence patients' awareness and willingness to use online hospitals. Currently, the public's awareness and usage of online hospitals is low. In fact, effort expectancy was the most important factor that influenced the use of online hospitals; being female and having a high education also played positive roles toward the use of mobile medical services.

Effects of respiratory disease on Kele piglets lung microbiome, assessed through 16S rRNA sequencing.

BACKGROUND AND AIM: Due to the incomplete development of the immune system in immature piglets, the respiratory tract is susceptible to invasion by numerous pathogens that cause a range of potential respiratory diseases. However, few studies have reported the changes in pig lung microorganisms during respiratory infection. Therefore, we aimed to explore the differences in lung environmental microorganisms between healthy piglets and piglets with respiratory diseases. MATERIALS AND METHODS: Histopathological changes in lung sections were observed in both diseased and healthy pigs. Changes in the composition and abundance of microbiomes in alveolar lavage fluid from eleven 4-week-old Chinese Kele piglets (three clinically healthy and eight diseased) were studied by IonS5™ XL sequencing of the bacterial16S rRNA genes. RESULTS: Histopathological sections showed that diseased pigs displayed more lung lesions than healthy pigs. Diseased piglets harbored lower bacterial operational taxonomic units, α-diversity, and bacterial community complexity in comparison to healthy piglets. Taxonomic composition analysis showed that in the diseased piglets, the majority of flora was composed of Ureaplasma, Mycoplasma, and Actinobacillus; while Actinobacillus, Sphingomonas, and Stenotrophomonas were dominant in the control group. The abundance of Ureaplasma was significantly higher in ill piglets (p<0.05), and the phylogenetic tree indicated that Ureaplasma was clustered in Ureaplasma diversum, a conditional pathogen that has the potential to affect the swine respiratory system. CONCLUSION: The results of this study show that the microbial species and structure of piglets' lungs were changed during respiratory tract infection. The finding of Ureaplasma suggested that besides known pathogens such as Mycoplasma and Actinobacillus, unknown pathogens can exist in the respiratory system of diseased pigs and provide a potential basis for clinical treatment.

Numerical Investigation into the Flow Characteristics of Gas Mixtures in Knudsen Pump with Variable Soft Sphere Model.

In Knudsen pumps with geometric configuration of rectangle, gas flows are induced by temperature gradients along channel walls. In this paper, the direct simulation Monte Carlo (DSMC) method is used to investigate numerically the flow characteristics of H2-N2 mixtures in the Knudsen pump. The variable soft sphere (VSS) model is applied to depict molecular diffusion in the gas mixtures, and the results obtained are compared with those calculated from a variable hard sphere (VHS) model. It is demonstrated that pressure is crucial to affecting the variation of gas flow pattern, but the gas concentration in H2-N2 mixtures and the collision model do not change the flow pattern significantly. On the other hand, the velocity of H2 is larger than that of N2. The velocities of H2 and N2 increase if the concentration of H2 rises in the gas mixtures. The results of velocity and mass flow rate obtained from VSS and VHS models are different. Finally, a linear relation between the decrease of mass flow rate and the increase of H2 concentration is proposed to predict the mass flow rate in H2-N2 mixtures.

Finite Element Study on the Impact Resistance of Laminated and Textile Composites.

The impact resistance of fiber-reinforced polymer composites is a critical concern for structure design in aerospace applications. In this work, experiments were conducted to evaluate the impact performance of four types of composite panels, using a gas-gun test system. Computational efficient finite element models were developed to model the high-speed ballistic impact behavior of laminate and textile composites. The models were first validated by comparing the critical impact threshold and the failure patterns against experimental results. The damage progression and energy evolution behavior were combined to analyze the impact failure process of the composite panels. Numerical parametric studies were designed to investigate the sensitivity of impact resistance against impact attitude, including impact deflection angles and projectile deflection angles, which provide a comprehensive understanding of the damage tolerance of the composite panels. The numerical results elaborate the different impact resistances for laminate and textile composites and their different sensitivities to deflection angles.

[Propensity score matching in SPSS].

OBJECTIVE: To realize propensity score matching in PS Matching module of SPSS and interpret the analysis results. METHODS: The R software and plug-in that could link with the corresponding versions of SPSS and propensity score matching package were installed. A PS matching module was added in the SPSS interface, and its use was demonstrated with test data. RESULTS: Score estimation and nearest neighbor matching was achieved with the PS matching module, and the results of qualitative and quantitative statistical description and evaluation were presented in the form of a graph matching. CONCLUSION: Propensity score matching can be accomplished conveniently using SPSS software.

[Analysis of X-rays of cervical imbalances syndrome before and after the treatment of osteopathy and traction intervention in 187 youth cases].

OBJECTIVE: To observe X-ray features of before and after treatment of cervical imbalance syndrome with osteopathy and traction intervention in youth patients, then to investigate the clinical effect of the treatment of the cervical imbalances syndrome in youth by osteopathy. METHODS: From September 2007 to December 2010, one hundred and eighty-seven students of 19 to 22 years (means 21 years) with neck pain as the main symptom in Beijing university of Chinese medicine were selected and divide them into osteopathy group and traction groups randomly. In osteopathy group, there were 94 patients including 40 males and 54 females; in traction group, there were 93 patients including 42 males and 51 females. The treatment of osteopathy group lasted for 3 weeks,three times per week; traction group by traction treatment three weeks,three times a week, too. X-ray before treatment and 3 weeks after treatment were collected. RESULTS: The osteopathy group:94 cases, before treatment, abnormal curvature in 57 cases, spinous position change in 45 cases and angular displacement in 44 cases, vertebral sliding in 15 cases, Ruth Jackson line intersect proneness change in 70 cases,stretch change in 47 cases; after treatment, abnormal curvature in 35 cases, spinous position change in 24 cases and angular displacement in 18 cases, vertebral sliding in 3 cases, Ruth Jackson line intersect proneness change in 41 cases, extension change in 33 cases; X-Ray measurement results: cervical curvature improved from (7.070 +/- 4.629) degrees before treatment to (7.660 +/- 4.156) degrees after treatment, angular displacement improved from (13.790 +/- 2.590) degrees before treatment to (11.050 +/- 2.560) degrees after treatment; vertebral sliding improved from (3.770 +/- 0.350) mm before treatment to (3.160 +/- 0.485) mm after treatment. The change of angular displacement and vertebral sliding were so significant before and after treatment in this group, there were statistical defferences between before and after the treatment (P < 0.01) in osteopathy group. The traction group: 93 cases, before treatment,abnormal curvature in 60 cases, spinous position change in 39 cases and angular displacement in 39 cases, vertebral sliding in 15 cases, Ruth Jackson line intersect proneness change in 70 cases, stretch in 47 cases; after treatment,abnormal curvature in 50 cases, spinous position change in 29 cases and angular displacement in 17 cases; vertebral sliding in 3 cases, Ruth Jackson line intersect proneness change in 41 cases, stretch in 33 cases; X-Ray measurement results: cervical curvature improved from (5.590 +/- 4.639) degrees before treatment to (5.990 +/- 4.330) degrees after treatment, angular displacement improved from (13.360 +/- 2.064) degrees before treatment to (11.210 +/- 1.872) degrees after treatment; vertebral sliding improved from (3.790 +/- 0.339) mm before treatment to (3.480 +/- 0.332) mm after treatment. The change of angular displacement and vertebral sliding were also so significant in traction group before and after treatment, there were statistical defferences between before and after the treatment (P < 0.01). CONCLUSION: (1) Pathological changes can be called youth cervical imbalance syndrome. (2) Stress points, angular displacement, cervical vertebral slip, curvature straightened, spinous position change are main X-ray performances. (3) Both osteopathy and traction intervention on are efficient in youth neck pain. (4) Youths cervical vertebra imbalance is early but reversible performance.

[Multiple linear regression analysis of X-ray measurement and WOMAC scores of knee osteoarthritis].

OBJECTIVE: To perform Multiple Linear Regression analysis of X-ray measurement and WOMAC scores of knee osteoarthritis, and to analyze their relationship with clinical and biomechanical concepts. METHODS: From March 2011 to July 2011, 140 patients (250 knees) were reviewed, including 132 knees in the left and 118 knees in the right; ranging in age from 40 to 71 years, with an average of 54.68 years. The MB-RULER measurement software was applied to measure femoral angle, tibial angle, femorotibial angle, joint gap angle from antero-posterir and lateral position of X-rays. The WOMAC scores were also collected. Then multiple regression equations was applied for the linear regression analysis of correlation between the X-ray measurement and WOMAC scores. RESULTS: There was statistical significance in the regression equation of AP X-rays value and WOMAC scores (P<0.05), while there was no statistical significance in the regression equation of lateral X-ray value and WOMAC scores (P>0.05). CONCLUSION: 1) X-ray measurement of knee joint can reflect the WOMAC scores to a certain extent. 2) It is necessary to measure the X-ray mechanical axis of knee, which is important for diagnosis and treatment of osteoarthritis. 3) The correlation between tibial angle,joint gap angle on antero-posterior X-ray and WOMAC scores is significant, which can be used to assess the functional recovery of patients before and after treatment.

[The clinical application of infrared imaging technology in teenagers with cervicodynia].

OBJECTIVE: To compare the temperature distribution of both sides of shoulder, provide objective reference for the application thermoview in the diagnosis of cervicodynia in teenagers. METHODS: Forty-five adolescents with cervicodynias from March 2009 to December 2009 were collected. There were 23 males and 22 females, with an average age of 21 years (ranged from 19 to 22 years). The course of disease ranged from 2 to 20 weeks (averaged 13 weeks). C7 horizontal line were used to divide the back into the neck area and shoulders area, and the midline to subdivide the chosen area into left and right area. Thermal infrared imaging was used to observe the temperature both sides of neck and shoulders, the data was analyzed by the computer. RESULTS: The temperature of shoulder was higher than neck. There were significant differences in the highest and average temperature both of the left and right side of neck and shoulder (P < 0.05), but no difference in the lowest temperature both of left and right side of neck. CONCLUSION: The thermal infrared imaging is important for diagnosing cervical imbalance syndrome, finding the sign of abnormal muscle metabolism of shoulder and providing the basis for prevention.

N'-(2-Hydr-oxy-3-methoxy-benzyl-idene)-1,3-benzodioxole-5-carbohydrazide monohydrate.

Single crystals of the title compound, C(16)H(14)N(2)O(5)·H(2)O, were obtained from a condensation reaction of 1,3-benzodioxole-5-carbohydrazide and 3-methoxy-salicylaldehyde in a 95% ethanol solution. The asymmetric unit consists of a Schiff base mol-ecule, which assumes an E configuration with respect to the C=N bond, and a water mol-ecule of crystallization. The dihedral angle between the two substituted benzene rings is 12.7 (2)°. In the crystal structure, mol-ecules are linked through inter-molecular N-H⋯O and O-H⋯O hydrogen bonds, forming layers parallel to the bc plane.