Relationship between chronic disease resource utilization and quality of life in coronary heart disease patients: A latent profile analysis.

AIMS: This study aimed to identify different profiles of chronic disease resource utilization among patients with coronary heart disease in Tibet and explore the relationship between these profiles and quality of life. DESIGN: A cross-sectional study. METHODS: Patients with coronary heart disease who were treated in a tertiary hospital in Tibet and its cooperative points from January 2021 to July 2021 were selected as the study participants. All participants completed a general information questionnaire, the Chronic Disease Resource Utilization Questionnaire (CIRS) and the Health Status Survey Short Form (SF-36). Chronic disease resource utilization was profiled, and its relationship to quality of life was explored using hierarchical linear regression. RESULTS: A total of 382 patients were enrolled in this study. Regarding chronic disease resource utilization, the participants were divided into three latent profiles: 'Poor utilization group' (n = 151), 'Effective utilization group' (n = 155) and 'Full utilization group' (n = 76). Different profiles of chronic disease resource utilization of patients were significantly associated with quality of life (R2 = .126, p < .001). CONCLUSION: Healthcare providers should identify patients with different profiles, define their utilization features of chronic disease resources and adopt targeted interventions to guide them in acquiring enough disease support resources to improve their quality of life. IMPLICATION: Understanding different resources using preferences of coronary heart disease patients can help healthcare providers and related sectors to provide other supports based on different profiles of patients, thus enhancing their quality of life. REPORTING METHOD: The study followed the STROBE guideline. NO PATIENT OR PUBLIC CONTRIBUTION: There was no patient or public involvement in the design of the study.

'I'm still young it doesn't matter' - A qualitative study on the neglect of prodromal myocardial infarction symptoms among young- and middle-aged adults.

AIM: To explore why young- and middle-aged adults ignore prodromal myocardial infarction symptoms from a life course and sociocultural perspective. DESIGN: A qualitative descriptive study. METHODS: We applied purposeful sampling to recruit participants from a tertiary hospital in Guangzhou from July to November 2021. Face-to-face interviews were performed. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis methods. RESULTS: Twenty-four young- and middle-aged adults diagnosed with acute myocardial infarction participated in this study. Analysis revealed three main themes: I'm still young, it will not happen to me; to be somebody and different roles, multiple pressures. Age-related self-confidence led to inappropriate perceptions and responses to prodromal symptoms among young- and middle-aged adults. These individuals strived to align their behaviours and attention with social expectations and self-expectations, underestimating the importance of perceiving the warning signs of acute myocardial infarction and seeking medical treatment. Pressure from social roles also prevented them from paying enough attention to prodromal symptoms. CONCLUSION: Targeted social support, public education and technologies should be provided to these individuals since they are pillars of the family and society. We also highlight how nurses can function these strategies appropriately. IMPACTS: This study contributes to a better understanding of the neglect of prodromal symptoms among young- and middle-aged adults. Its results enhance our understanding of the perception of and coping with prodromal symptoms among this population, which will help avoid the burden caused by acute myocardial infarction. PATIENT OR PUBLIC CONTRIBUTION: The patients involved in our study shared their experiences and insights to provide new perspectives regarding the neglect of prodromal myocardial infarction symptoms among young- and middle-aged adults.

Silencing of circARHGAP12 inhibits the progression of atherosclerosis via miR-630/EZH2/TIMP2 signal axis.

Atherosclerosis (AS) is a common disease that seriously threatens human health. So far, the pathogenesis of AS has not been fully understood. This project investigates the effects of circARHGAP12 on AS and its regulatory mechanism. ApoE-/- knockout mice (ApoE) were adopted and reared with a high-fat diet to construct an AS model. Lentivirus was established to knock down the expression of circARHGAP12 in mice. After 12 weeks, the aorta was removed and the expression of circARHGAP12 was detected. Vascular oil red O staining was used to detect the degree of AS. The expression of inflammatory factors was detected by ELISA. Aortic smooth muscle cells (MASMCs) were cultured to evaluate the effects of circARHGAP12 on the phenotype of MASMCs. RNA pull-down and luciferase assay were used to verify the downstream target genes of circARHGAP12. In addition, the effects of circARHGAP12 on MASMCs proliferation and migration were detected by MTT and transwell assay. Compared with the normal group, the expression of circARHGAP12 in the MASMCs under ox-LDL treatment was elevated, and circARHGAP12 silencing could inhibit AS in vitro and in vivo. The results of the mechanism study showed that circARHGAP12 can directly bind with miR-630. In addition, miR-630 can also target EZH2 to modulate the transcription of TIMP2 and to influence the migration of MASMCs. circARHGAP12 is upregulated in AS. CircARHGAP12 knockdown can inhibit the progression of AS. This study expands on the role of circRNA in AS and provides potential targets for the treatment of AS.

The interaction between black carbon and planetary boundary layer in the Yangtze River Delta from 2015 to 2020: Why O3 didn't decline so significantly as PM2.5.

Since the Air Pollution Prevention and Control Action Plan (air clean plan) issued in 2013, air quality has been in continuous improvement. The second stage of air clean plan since 2018 was focused on O3 controlling, but it still didn't decline so significantly as PM2.5. This study conducted a long-term observation on black carbon (BC) and utilized the observational data of other air pollutants (PM2.5, PM10, NO2, SO2, CO and O3), the meteorological elements and the vertical sounding data of PBL in Nanjing. In the daytime (08:00-20:00), PM2.5 kept decreasing from 2015 to 2020 at the rate of 4.8 µg⋅m-3⋅a-1, however, BC increased at the rate of 0.6 µg⋅m-3⋅a-1, which has led to the continuous growth of BC/PM2.5 (0.9%⋅a-1). However, during this period, O3 was relatively stable and, in 2020, it returned below its value in 2015 after slight increases in 2017 and 2018. Meanwhile, the average surface temperature had increased by around 1.0 °C during 2015-2019 at the rate of 0.3 °C⋅a-1. Also, the average height of the inversion layer had increased significantly by 494.0 and 176.7 m at 20:00 and 08:00, whose growth ratio was up to 57% and 25%, respectively. The above observation results have formed a set of chain reactions as follows. The growth of the surface BC caused the surface temperature to rise due to the increasing heating effect of BC. The continuous growth of the surface temperature made it easier for the PBL height to develop, which led to the lift of the inversion layer in the PBL and the larger atmospheric environment capacity. Ultimately, it is conducive to the diffusion of the near surface pollutants, thus helping reduce their concentrations, which offsets the increasing tendency of O3 and add to the decreasing trend of PM2.5. This phenomenon is the most remarkable in summer, with the fastest increasing rate of temperature (0.8 °C⋅a-1) and O3 (3.9 µg⋅m-3⋅a-1) during 2015-2019 (excluding 2020 to erase the great effect of COVID-19 lockdown on emissions).

SASMOTE: A Self-Attention Oversampling Method for Imbalanced CSI Fingerprints in Indoor Positioning Systems.

WiFi localization based on channel state information (CSI) fingerprints has become the mainstream method for indoor positioning due to the widespread deployment of WiFi networks, in which fingerprint database building is critical. However, issues, such as insufficient samples or missing data in the collection fingerprint database, result in unbalanced training data for the localization system during the construction of the CSI fingerprint database. To address the above issue, we propose a deep learning-based oversampling method, called Self-Attention Synthetic Minority Oversampling Technique (SASMOTE), for complementing the fingerprint database to improve localization accuracy. Specifically, a novel self-attention encoder-decoder is firstly designed to compress the original data dimensionality and extract rich features. The synthetic minority oversampling technique (SMOTE) is adopted to oversample minority class data to achieve data balance. In addition, we also construct the corresponding CSI fingerprinting dataset to train the model. Finally, extensive experiments are performed on different data to verify the performance of the proposed method. The results show that our SASMOTE method can effectively solve the data imbalance problem. Meanwhile, the improved location model, 1D-MobileNet, is tested on the balanced fingerprint database to further verify the excellent performance of our proposed methods.

Annual variations of black carbon over the Yangtze River Delta from 2015 to 2018.

In this study, the black carbon (BC) measurements in the atmosphere of Nanjing, China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer. By combining dataset of PM2.5, PM10, CO, NO2, SO2, O3 and meteorological parameters, the temporal variations and the source apportionment of BC were given in this study. The results showed that the PM2.5 mass concentrations decreased in Nanjing, with an average annual rate of variation of 6.50 µg/(m3⋅year). Differently, the annual average concentrations of BC increased with an average annual variation rate of 214.71 ng/(m3⋅year). The seasonal variations showed the pattern of BC mass concentrations in winter > autumn > spring > summer. The diurnal variations of BC mass concentrations showed a double-peak in all four seasons. The first peak occurred at approximately 7:00 in spring, summer and autumn and around 8:00 in winter. The second peak took place after 18:00. The average AAE (absorption Ångström exponent) was 1.26 with a maximum of 1.35 during wintertime and the lowest (1.12) during summertime. In addition, the AAE was smaller in the daytime than that at night, with a minimum occurring between 13:00 and 14:00. BC and visibility show a good power-function relationship at different humidity levels. The average values of the visibility thresholds of the BC mass concentrations in spring, summer, autumn and winter were 1.326, 5.522, 1.340 and 0.708 µg/m3, respectively. The greater the relative humidity, the smaller the visibility threshold for the BC mass concentrations was.

Alum/CpG adjuvant promotes immunogenicity of inactivated SARS-CoV-2 Omicron vaccine through enhanced humoral and cellular immunity.

The SARS-CoV-2 Omicron variant, which was classified as a variant of concern (VOC) by the World Health Organization on 26 November 2021, has attracted worldwide attention for its high transmissibility and immune evasion ability. The existing COVID-19 vaccine has been shown to be less effective in preventing Omicron variant infection and symptomatic infection, which brings new challenges to vaccine development and application. Here, we evaluated the immunogenicity and safety of an Omicron variant COVID-19 inactivated vaccine containing aluminum and CpG adjuvants in a variety of animal models. The results showed that the vaccine candidate could induce high levels of neutralizing antibodies against the Omicron variant virus and binding antibodies, and significantly promoted cellular immune response. Meanwhile, the vaccine candidate was safe. Therefore, it provided more foundation for the development of aluminum and CpG as a combination adjuvant in human vaccines.

The effect of illness perception on psychosocial adjustment of patients with breast cancer and their spouses: actor-partner independence model.

OBJECTIVE: With the increase in the prevalence rate and improvements in the survival of breast cancer patients, there is a growing interest in understanding the level of psychosocial adjustment in these patients. The study aimed to describe the illness perception and psychosocial adjustment levels of both breast cancer patients and their spouses, to use the Actor-Partner Interdependence Model (APIM) to clarify the actor-partner relationships between spouses, and to explore the impact of illness perception on psychosocial adjustment to the disease within the joint actions of both spouses. METHODS: A total of 216 female patients with breast cancer and their spouses participated in the study. They were selected from two tertiary hospitals in Guangdong Province, China from October 2022 to May 2023 using a convenience sampling method. The participants were assessed using the Brief Illness Perception Questionnaire and the Psychosocial Adjustment to Illness Scale to examine the relationship between illness perception and psychosocial adjustment. AMOS24.0 was used to test and analyze the actor-partner interdependence model. RESULTS: The illness perception score (57.75 ± 10.91) was slightly higher than that of the spouse (57.10 ± 11.00), and the psychosocial adjustment score (64.67 ± 6.33) was slightly lower than that of the spouse (64.76 ± 7.49). The results of the actor-partner interdependence model indicated that there was a couple partner between breast cancer patients and their spouses: the spouse's illness perception significantly affected the patient's psychosocial adjustment (ß = 0.095, p = 0.015); the patient's illness perception also significantly affected the spouse's psychosocial adjustment (ß = 0.106, p = 0.033). Among them, the patient's psychosocial adjustment was found to be related to the patient's illness comprehensibility or coherence of illness (ß = 0.433, p = 0.009), the spouse's emotional illness representation (ß = 0.218, p = 0.037), and the spouse's illness comprehensibility or coherence of illness (ß = 0.416, p = 0.007), while the spouse's psychosocial adjustment was only related to the spouse's illness comprehensibility or coherence of illness (ß = 0.528, p = 0.007). CONCLUSIONS: The psychosocial adjustment of breast cancer patients is affected by both their own and spouse's illness perception. Therefore, in the future, the healthcare staff can implement early psychological interventions for patients diagnosed with breast cancer and their spouses as a unit to promote the psychosocial adjustment of them.

Health literacy and quality of life of patients with coronary heart disease in Tibet, China: The mediating role of self-efficacy and self-management.

BACKGROUND: The disease burden of coronary heart disease patients in Tibet, China, ranks high in the country. Due to the local culture and environment, patients with coronary heart disease have increased risk factors for the disease, and their survival is worrisome. OBJECTIVES: The purpose of this study was to determine the relationship between health literacy and quality of life for patients with coronary heart disease in Tibet, China, and to explore the mediating roles of self-efficacy and self-management. METHODS: A cross-sectional study was conducted from August 2020 to July 2021 in Tibet. A total of 258 patients with coronary heart disease in Tibet participated. Self-reported questionnaires were used to assess health literacy, self-efficacy, self-management, and quality of life. Pearson correlation analysis and the SPSS PROCESS macro were used to analyze the data. RESULTS: The mean total score for the health literacy of patients with coronary heart disease in Tibet was 3.59 ± 0.80 points, showing the existence of a limited level of literacy. The quality of life was of an average level, with scores of 57.20 ± 21.70 points and 63.63 ± 20.66 points for physical and mental status, respectively. Self-efficacy and self-management mediated the relationship between health literacy and quality of life. CONCLUSIONS: Self-efficacy and self-management mediate the relationship between health literacy and quality of life. Targeted interventions for health literacy, self-efficacy, and self-management skills are important to improve the quality of life of Tibetan patients with coronary heart disease.

Self-efficacy and self-management mediate the association of health literacy and quality of life among patients with TB in Tibet, China: a cross-sectional study.

BACKGROUND: This study aimed to analyze the relationship between health literacy and quality of life in patients with TB in Tibet and explore the mediating effects of self-efficacy and self-management in the relationship between health literacy and quality of life. METHODS: We used a convenience sampling method to select 271 cases of patients with TB in Tibet to conduct a survey of their general information, health literacy, self-management, self-efficacy and quality of life, and to construct structural equation models. RESULTS: The total health literacy score of patients with TB in Tibet was 84.28±18.57, while the lowest score was for information acquisition ability (55.99±25.66). Scores for quality of life were generally lower than the norm (patients with chronic diseases from other cities in China) (p<0.01). Moreover, self-efficacy and self-management mediated the relationship between health literacy and quality of life (p<0.05). CONCLUSIONS: In Tibet, patients with TB have a low level of health literacy and an average level of quality of life. Emphasis should be placed on improving information access literacy, role-physicals and role-emotional to improve overall quality of life. The mediating roles of self-efficacy and self-management between health literacy and quality of life may provide a basis for further interventions.

Design, synthesis, and SAR study of novel flavone 1,2,4-oxadiazole derivatives with anti-inflammatory activities for the treatment of Parkinson's disease.

Inflammation is one of a major feature of Parkinson's disease (PD) which poses a threat to people's health in the world. It has been reported that antioxidation and anti-inflammation have significant effects on the treatment of PD. 1,2,4-oxadiazole and flavone derivatives have remarkable antioxidant and anti-inflammatory activities. In order to find highly effective drugs for PD treatment, based on the remarkable anti-inflammatory and antioxidant activities of the 1,2,4-oxadiazole pharmacophore and the flavonoid pharmacophore, we designed and synthesized a novel series of 3-methyl-8-(3-methyl-1,2,4-oxadiazol-5-yl)-2-phenyl-4H-chromen-4-one derivatives by pharmacophore combination, and evaluated their anti-inflammatory and antioxidation activities for PD treatment. Preliminary structure-activity relationship (SAR) analysis was conducted by their inhibitory activities against reactive oxygen species (ROS) and NO release in LPS-induced BV2 Microglia cells, and the optimal compound Flo8 exhibited the most potent anti-inflammatory and antioxidant activities. Both in vivo and in vitro results showed that Flo8 inhibited neuronal apoptosis by inhibiting inflammatory and apoptotic signaling pathways. In vivo studies also showed that the compound Flo8 ameliorated motor and behavioral deficits and increased serum dopamine levels in MPTP-induced PD model mice. Taken together, this study demonstrated the compound Flo8 could be a promising agent for the treatment of PD.

Effects of Data Augmentation with the BNNSMOTE Algorithm in Seizure Detection Using 1D-MobileNet.

Automatic seizure detection technology has important implications for reducing the workload of neurologists for epilepsy diagnosis and treatment. Due to the unpredictable nature of seizures, the imbalanced classification of seizure and nonseizure data continues to be challenging. In this work, we first propose a novel algorithm named the borderline nearest neighbor synthetic minority oversampling technique (BNNSMOTE) to address the imbalanced classification problem and improve seizure detection performance. The algorithm uses the nearest neighbor notion to generate nonseizure samples near the boundary, then determines the seizure samples that are difficult to learn at the boundary, and lastly selects seizure samples at random to be used in the synthesis of new samples. In view of the characteristic that electroencephalogram (EEG) signals are one-dimensional signals, we then develop a 1D-MobileNet model to validate the algorithm's performance. Results demonstrate that the proposed algorithm outperforms previous seizure detection methods on the CHB-MIT dataset, achieving an average accuracy of 99.40%, a recall value of 87.46%, a precision of 97.17%, and an F1-score of 91.90%, respectively. We also had considerable success when we used additional datasets for verification at the same time. Our algorithm's data augmentation effects are more pronounced and perform better at seizure detection than the existing imbalanced techniques. Besides, the model's parameters and calculation volume have been significantly reduced, making it more suitable for mobile terminals and embedded devices.

Analysis of gut microbiota in patients with acute myocardial infarction by 16S rRNA sequencing.

Background: An increasing number of studies have shown that gut microbiota are associated with human cardiovascular disease, but the characteristics of intestinal flora in patients with acute myocardial infarction (AMI) are still unclear. In this study, we aimed to investigate the difference of intestinal microflora between patients with AMI and healthy people, and to find the effect of percutaneous coronary intervention (PCI) on intestinal microflora. Methods: A total of 60 stool samples and 60 peripheral blood samples were collected from 20 previously diagnosed AMI patients and 20 healthy people serving as controls. Gut microbiota communities were analyzed via 16 ribosomal RNA-sequencing (16S rRNA). Gut microbiota-derived metabolites, trimethylamine N-oxide (TMAO) and short-chain fatty acids (SCFA), in the blood were detected using stable isotope dilution high-performance liquid chromatography with on line electrospray ionization tandem mass spectrometry (LC/MS/MS). Results: The results showed that a distinct pattern of gut microbiota was observed in AMI patients compared to healthy controls. AMI patients had lower microbiological richness but no significant change in diversity. Bacteroidetes and Verrucomicobia showed an upward trend, whereas Proteobacteria showed a downward trend in AMI patients. During a longitudinal study to compare the changes in bacteria before and after treatment, we found routine cardiac admission therapy 1 week after PCI surgery had no effect on the microbial community structure in patients. There were significantly higher levels of plasma TMAO in AMI patients' microbiota than that in the control group. Contrarily, there was no obvious change in SCFA. Conclusions: The gut microbiota of patients with AMI differs from that of normal people, and the metabolic products of microflora are more abundant in the plasma of AMI than control cases. Microflora may act on the cardiovascular system through metabolites, and regulation of the microfloral structure may be used in the future treatment of cardiovascular diseases.

Enhanced Dewatering of Activated Sludge by Skeleton-Assisted Flocculation Process.

Sludge dewatering is the fundamental process of sludge treatment. Environmentally friendly and efficient sludge conditioning methods are the premises of sludge to achieve dehydration reduction and resource utilization. In response to sewage plant sludge dehydration, fly ash (FA), polymerized aluminum chloride (PAC), and polymer sulfate (PFS) were studied separately to determine their sludge dehydration performance, and the effects of these three conditioner composite regulations on sludge dehydration properties were studied. Compared to the sludge treated only with conditioner, the average particle size of floc increased and the organic matter content in the filtrate decreased. The sludge dewatering efficiency after the conditioning effect is better than that after conditioning a single conditioner. After PFS conditioning with fly ash, the water content and specific resistance (SRF) of the sludge cake can be reduced to 76.39% and 6.63 × 1010 m/kg, respectively. The moisture content and specific resistance (SRF) of the sludge cake can be reduced to 76.10% and 6.91 × 1010 m/kg, respectively. The pH of the sludge and filtrate changed slightly after PAC conditioning with fly ash coupling. These results indicate that fly-ash coupled with PAC and fly-ash coupled with PFS are expected to become a novel and effective environmental protection combined conditioning method for sludge dewatering.

Application of Advanced Oxidation Technology in Sludge Conditioning and Dewatering: A Critical Review.

Sludge dewatering is an important link in sludge treatment. In practical engineering, the dewatering effect of unconditioned sludge is very poor. The use of advanced oxidation technology can improve sludge dewatering performance, reduce sludge capacity, and remove micro-pollutants, which is beneficial for sludge post-treatment and disposal. Based on the current status of sludge conditioning and dehydration, the characteristics of the advanced oxidation method for sludge dehydration were systematically explained using various free radical reaction mechanisms and dehydration conditions. The effects of various advanced oxidation technologies on sludge conditioning and dewatering has been extensively discussed. Finally, the application prospects of the advanced oxidation technology in sludge conditioning and dewatering are presented.

[Distribution Characteristics and Source Analysis of Water-soluble Ions in Particulate Matter Under Different Weather Processes in Nanjing].

From November 16 to 28 2018, water-soluble ions in particulate matter and some trace gases in Nanjing City were observed using the online gas composition and aerosol monitoring system MARGA ADI 2080. Combined with meteorological elements and sounding data, the distribution characteristics and day-night differences of pollutants and water-soluble ions during haze, fog, clear, and precipitation processes were analyzed. The results show that the average concentration of PM2.5 varied from 26.9µg·m-3 (precipitation) to 96.4µg·m-3 (haze) while total water-soluble ions varied between 23.7µg·m-3 (precipitation) and 89.7µg·m-3 (haze). The ranked order of ion concentrations was NO3- > NH4+ > SO42- > Cl- > K+ > Ca2+ > Na+ > Mg2+ during haze and fog events, and NO3- > SO42- > NH4+ > Cl- > Ca2+ > K+ > Na+ > Mg2+ during clear weather and precipitation period. The diurnal distributions of water-soluble ions were quite different under the four conditions, although SO42-, NO3-, and NH4+(SNA) were ranked haze > fog > clear > precipitation for both day and night periods. According to the PMF source analysis, secondary sources were the main factors affecting haze; secondary sources, sea salt, and combustion sources were the main pollution sources to foggy conditions; and the removal effect of precipitation on coal-fired sources and secondary sources was more notable than during clear conditions.

Concentration and atmospheric transport of PM2.5-bound polycyclic aromatic hydrocarbons at Mount Tai, China.

Atmospheric PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) pose a major threat to human health. At present, studies on PAHs in the atmosphere have mostly focused on their concentration levels and source apportionment, whereas studies on the vertical transport of PAHs in the atmosphere are limited. However, the vertical transport of PAHs is important for their diffusion near the ground and their long-range transport at higher altitude. In this study, PM2.5 samples were collected simultaneously at the summit and foot of Mount Tai (MTsummit and MTfoot, respectively) from May to June 2017, and the concentrations of 18 PAHs in the samples were determined. The total concentration of PAHs at MTsummit was 2.406 ng m-3, which was well below the pollution levels of domestic cities, whereas that at MTfoot was as high as 9.068 ng m-3, which was within the range of pollution levels in domestic cities. The total carcinogenic risk for both MTsummit and MTfoot was within the potential risk range. Given the source of PAHs and the diurnal variation of the planetary boundary layer, the PAHs showed opposite diurnal trends at MTsummit and MTfoot. Vertical transport was an important source of daytime PAHs at MTsummit, and the vertical transport efficiency of PAHs decreased with an increasing ring number; this may be due to the combined effects of gas-particle partitioning and chemical reactions. Furthermore, PAHs originating in the surrounding high-emission provinces can affect the Mount Tai area via atmospheric trans-regional transport, and the BaP/BeP ratio is a useful indicator of the transport distance of PAHs.

[Change in Characteristics of Pollution Gas and Water-soluble Ions at Different Development Stages of Haze].

To explore the variation in characteristics of atmospheric pollutants at different stages of haze, the monitor for aerosols and gases in ambient air (MARGA) was used to observe the concentrations of precursor pollutants (NH3, HNO3, and SO2) and eight water-soluble ions in a regional haze in the Yangtze River Delta region from November 18 to December 07, 2018. Combined with environmental data (PM2.5, NO2, CO, and O3) and meteorological data, the causes of regional haze formation, diurnal variation characteristics of air pollutants, and distribution characteristics of air pollutants in different stages of haze were analyzed. The results showed that the Yangtze River Delta region was mainly controlled by a ridge of high pressure during the haze process and the weather situation was stable, which was conducive to the accumulation of air pollutants. On hazy days, the concentrations of PM2.5, NO2, NO3-, SO42-, NH4+, Cl-, and Na+ were (118.91±39.23), (61.62±26.34), (45.64±16.01), (18.80±8.02), (20.82±7.16), (3.02±2.25), and (0.23±0.22) µg·m-3, respectively, and these were 2.73, 1.63, 2.64, 1.94, 2.50, 2.05, and 2.56 times the levels found on clean days, respectively. The concentration of CO was (1.34±0.39) mg·m-3 on hazy days, which was 1.86 times that found on clean days. Diurnal variation characteristics of different air pollutants were different, as were the distribution characteristics of air pollutants at different haze stages. The concentrations of SO2 was the highest in the haze occurrence stage. The concentrations of PM2.5, NO2, NH3, CO, and SNA were highest in the haze development stage, and the concentrations of O3, Cl-, Na+, and K+ were highest in the haze dissipation stage. The relative contributions of SNA to PM2.5 in different stages of haze could reach 94%-96%, and their growth rate was largest in the development stage. The order of growth rate was NO3- > NH4+ > SO42-. SNA mainly existed in the form of NH4NO3 on clean days and in the occurrence and development stages, and (NH4)2SO4 in the dissipation stage. This haze process was mainly caused by the growth of NO3-, which was mainly generated by gas-phase homogeneous phase reaction, and NO3-contributes 51.06%, 51.85%, and 48.22%, respectively, to PM2.5 in the occurrence, development, and dissipation stages of haze.

The Out-of-Plane Compression Behavior of Cross-Ply AS4/PEEK Thermoplastic Composite Laminates at High Strain Rates.

The dynamic mechanical behavior of thermoplastic composites over a wide range of strain rates has become an important research topic for extreme environmental survivability in the fields of military protection, aircraft safety, and aerospace engineering. However, the dynamic compression response in the out-of-plane direction, which is one of the most important loading conditions resulting in the damage of composite materials, has not been investigated thoroughly when compared to in-plane compression and tensile behavior under high strain rates. Thus, we used split Hopkinson pressure bar (SHPB) tests to conduct the out-of-plane compression test of cross-ply carbon fiber-reinforced polyetheretherketone (AS4/PEEK) composite laminates. Afterward, the damage mechanism under different strain rates was characterized by the macrostructure morphologies and scanning electron microscope micrographs. Two major cases of the incomplete failure condition and complete failure condition were discussed. Dynamic stress-strain curves expound the strain rates dependencies of elastic modulus, failure strength, and failure strain. An obvious spring-back process could be observed under incomplete failure tests. For the complete failure tests, secondary loading could be observed by reconstructing and comparing the dynamic response history. Lastly, various failure modes that occurred in different loading strain rates illustrate that the damage mechanism also shows obvious strain rate sensitivity.