•A novel hierarchical composite of NiFe2O4/N-GN/ZnO was fabricated successfully.•A strongest RL of −70.7 dB can be obtained with a filler content of 20 wt%.•The absorber exhibits superior microwave ...absorption properties.•The enhanced microwave absorption mechanisms are investigated in detail.
Hierarchical composites containing both magnetic loss and dielectric loss materials prepared through rational structure design are highly popular for high-performance microwave absorbers due to their suitable impedance matching and strong attenuation constant. In this work, NiFe2O4/N-GN/ZnO hierarchical composite was synthesized by growing ZnO nanoflowers on magnetic graphene. The effects of this unique microstructure on the electromagnetic (EM) wave absorption performances of the composites were studied. The microstructure, compositions and EM parameters of the obtained samples were investigated by various techniques. Results showed that NiFe2O4/N-GN/ZnO composite showed enhanced EM wave absorption properties compared with NiFe2O4/N-GN. With a low filler loading of 20 wt%, the strongest reflection loss (RL) was as high as −70.7 dB at 13.5 GHz and the frequency bandwidth (RL over −10 dB) reached 3.5 GHz (11.7–15.2 GHz) with an absorber thickness of 2.7 mm. These results demonstrate that the NiFe2O4/N-GN/ZnO hierarchical composite is an ideal candidate for lessening EM wave interference with its advantages of light weight, strong absorption and broad frequency bandwidth.
•A novel polyaniline coated MOF (Fe) was synthesized via a two-step method.•The maximum reflection loss of MOF (Fe)/PANI composite can achieve −41.4dB at 11.6GHz with a thickness of 2mm.•The ...absorption bandwidth exceeding −10dB is almost up to 5.5GHz (from 9.8 to 15.3GHz).
A hybrid polyaniline coated metal organic framework (MOF/PANI) was designed and fabricated via hydrothermal and in situ chemical polymerization methods The microstructure and morphology were examined by XRD, FTIR, FESEM and TEM. The results showed that MOF (Fe) particles were completely coated by PANI and formed a core-shell composite. The hybrid MOF (Fe)/PANI composite exhibited enhanced EM wave absorption capability compared with MOF (Fe), including the higher absorption intensity (−41.4dB at 11.6GHz) and excellent absorption bandwidth (5.5GHz exceeding −10dB with an only thickness of 2mm), which was due to enhanced interfacial effects, attenuation constant and the synergic effect between MOF (Fe) and PANI. Therefore, such a core-shell MOF (Fe)/PANI composite is a promising absorber for application in microwave absorption field.
•The sandwich structure of FeCo@RGO@PPy was synthesized via a three-step method.•The ternary composite has a ferromagnetic behavior.•The maximum reflection loss of FeCo@RGO@PPy composite can reach ...−40.7dB at 4.5GHz with a coating layer thickness of 2.5mm.•The absorption bandwidth exceeding −10dB is 5.7GHz (3.1–6GHz and 12.8–15.6GHz).
In this work, a ternary sandwich structure of FeCo@RGO@PPy was successfully fabricated by a three-step method. The structure and morphology of samples were characterized by XRD, FTIR, XPS, TEM and FESEM. TEM and FESEM images indicate that FeCo particles with a size of about 20–40nm are grown on surface of RGO@PPy, between RGO and PPy. VSM results reveal that FeCo@RGO@PPy composite possesses a ferromagnetic behavior, and the electromagnetic wave absorption properties of its were investigated at 2–18GHz. The maximum reflection loss of ternary composite can reach −40.7dB at 4.5GHz and the absorption bandwidth with the reflection loss exceeding −10dB is 5.7GHz (3.1–6GHz and 12.8–15.6GHz) with the thickness of 2.5mm, which shows an improved microwave absorption properties compared with FeCo. The microwave absorption mechanisms were also investigated in detail.
Existing research has extensively explored the relationship between government trust and compliance behaviour, but significant controversies exist. Some studies suggest a strong positive correlation ...between the two. Other studies have found that government trust hinders compliance behaviour. However, during the pandemic, the effectiveness of public health policies largely depends on the public's compliance with these policies. To examine the aforementioned controversies, this study utilizes survey data on the Chinese population during the COVID-19 period to explore the relationship between compliance with public health policies and government trust.
The study conducted a questionnaire survey of 1,395 individuals from 25 provinces in China from mid-November to mid-December 2022. Firstly, we categorized the public's compliance behaviour with public health policies based on the results of factor analysis. Subsequently, we examined the impact of government trust and professional trust on compliance behaviour with public health policies by constructing a structural equation model.
Based on the results of factor analysis, we classified public adherence to public health policies into protective compliance and restrictive compliance. Results from the structural equation model show a positive correlation between the public's trust in the government and both protective and restrictive compliance, with a stronger influence on protective compliance. Government trust also exerts a positive impact on restrictive compliance behaviour through professional trust. Additionally, the study indicates a significant positive correlation between the public's professional trust and restrictive compliance, while it does not significantly affect protective compliance. Moreover, the public from rural areas demonstrates a greater willingness to adhere to both types of public health policies. Married individuals exhibit a stronger inclination toward protective compliance, while females show a stronger tendency toward restrictive compliance.
The study revealed a significant positive impact of government trust and professional trust on compliance behaviour with public health policies during the COVID-19 pandemic, refuting any negative correlation between government trust and compliance behaviour. Normative motivations for compliance behaviour had a substantial impact on adherence. These findings offer valuable insights for future public health crisis management and public policy formulation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Protecting groundwater from nitrogen contamination is an important public-health concern and a major national environmental issue in China. In this study, we monitored water quality in 29 wells from ...2009 to 2010 in a village in Shanghai city, whick belong to typical rural-urban continuum in China. The total N and NO(3)-N exhibited seasonal changes, and there were large fluctuations in NH(4)-N in residential areas, but without significant seasonal patterns. NO(2)-N in the water was not stable, but was present at high levels. Total N and NO(3)-N were significantly lower in residential areas than in agricultural areas. The groundwater quality in most wells belonged to Class III and IV in the Chinese water standard, which defines water that is unsuitable for human consumption. Our health risk assessments showed that NO(3)-N posed the greatest carcinogenic risk, with risk values ranging from 19×10(-6) to 80×10(-6), which accounted for more than 90% of the total risk in the study area.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aims: Metabolic syndrome (MetS) has become a worldwide epidemic; however, few studies have described its status in Chinese children. This study aimed to estimate MetS status and its associations with ...geography, economic development, birth weight, and parental education of Chinese children and adolescents. Methods: Data were derived from 15,045 participants aged 7–18 years across seven Chinese provinces. Physical measurement and blood tests were conducted to assess the five classical MetS components described by the International Diabetes Federation, including abdominal obesity (the essential component), high blood pressure, low high-density cholesterol (HDL-C), high triglyceride, and elevated fasting glucose (FG). Logistic regression was adopted to explore possible associations between MetS and other factors. Results: Overall, MetS prevalence was 2.3%, higher in males (2.8% vs. 1.7% in females), northern regions (3.1%), more developed regions (2.9%), and older participants (aged 16–18 years) (P＜0.05 for all). Among the five MetS components, abdominal obesity and low HDL-C level were most prevalent (21.8% and 14.4%), and 35.9% of the participants had at least one component. In logistic regression, MetS itself did not correlate with birth weight or parental education. High birth weight was positively correlated with abdominal obesity (odds ratio, 1.48) butnegatively associated with elevated FG (odds ratio, 0.49). Concusions: MetS itself was not common in Chinese children and adolescents, whereas its certain components were far more prevalent. Children from North China, more-developed areas, and at an older age were more likely to develop MetS. Strategies designed to prevent pediatric MetS in China should focus on prevalent components as well as its geographic and economic development predilections.
Thermal analysis is an effective mean to study the crystallization of polymers. Fast scanning chip calorimetry (FSC) has ultra-high cooling and heating rate and plays an important role in the study ...of crystallization behavior. The crystallization kinetics of poly (
l
-lactic acid) (PLLA) with amino polyhedral oligomeric silsesquioxane (POSS-NH
2
) and polyethylene glycol-grafted POSS (POSS-PEG) was investigated by traditional differential scanning calorimetry (DSC) and FSC. The results show that the addition of POSS-PEG has a better promoting effect on the crystallization rate of PLLA than POSS-NH
2
. And there are two differences between the results of FSC and DSC: firstly, FSC can effectively avoid the nucleation and crystallization behavior in the cooling process and ensure that the crystallization process occurs completely in the isothermal stage, while DSC cannot; second, the measured crystallization rate by FSC is lower than the traditional DSC data. In a word, POSS plays a role of nucleation agent in PLLA crystallization, and PEG as nucleation accelerator further improves the crystallization rate; FSC can effectively avoid the nucleation and crystallization in the cooling and heating process.
Epigenetic modifications are plausible molecular sources of phenotypic heterogeneity across schizophrenia patients. The current study investigated biological heterogeneity in schizophrenia using ...peripheral epigenetic profiles to delineate illness subtypes independent of their phenomenological manifestations. We applied epigenome-wide profiling with a DNA methylation array from blood samples of 63 schizophrenia patients and 59 healthy controls. Non-negative matrix factorization (NMF) and k-means clustering were performed to identify DNA methylation-related patient subtypes. The validity of the partition was tested by assessing the profile of the T cell receptor (TCR) repertoires. The uniqueness of the identified subtypes in relation to brain structural and clinical measures were evaluated. Two distinct patterns of DNA methylation profiles were identified in patients. One subtype (60.3% of patients) showed relatively limited changes in methylation levels and cell composition compared to controls, while a second subtype (39.7% of patients) exhibited widespread methylation level alterations among genes enriched in immune cell activity, as well as a higher proportion of neutrophils and lower proportion of lymphocytes. Differentiation of the two patient subtypes was validated by TCR repertoires, which paralleled the partition based on DNA methylation profiles. The subtype with widespread methylation modifications had higher symptom severity, performed worse on cognitive measures, and displayed greater reductions in fractional anisotropy of white matter tracts and evidence of gray matter thickening compared to the other subtype. Identification of a distinct subtype of schizophrenia with unique molecular, cerebral, and clinical features provide a novel parcellation of the schizophrenia syndrome with potential to guide development of individualized therapeutics.
The coprecipitation of dissolved organic matter (DOM) and phosphate with Fe(III) at the sediment-water interface plays an important role in the biogeochemical cycle of organic carbon (OC) and ...phosphorus (P) in aquatic ecosystems. However, studies remain limited towards understanding the strength of ternary DOM-phosphate-Fe(III) coprecipitation in sequestering OC and P. Here, we investigated the behaviors of humic acid (HA) and phosphate during their coprecipitation with Fe(III) and compared the coprecipitation behaviors with those during the adsorption process. The results showed that the coprecipitation of HA and phosphate with Fe(III) enhanced as pH decreased or initial Fe(III) concentrations increased. The presence of phosphate had a moderate inhibition effect on HA coprecipitation, leading to 3%–37% of reduction in precipitated HA. Changes in optical properties of DOM (i.e., SUVA254, E2/E3, and fluorescent components) showed that macromolecular, aromatic molecules preferentially coprecipitated, and this selectivity pattern was not influenced by the presence of phosphate. Compared to the adsorption of HA and phosphate to goethite, coprecipitation with Fe(III) displayed stronger binding ability, sequestering more than10 times of HA and phosphate, and was more efficient in sequestering protein-like compounds. The inhibitory effect of phosphate on HA sequestration was weaker during coprecipitation than during adsorption. Moreover, coprecipitation led to a lower degree of compositional fractionation of HA than adsorption, which may be explained by that inclusion, an important pathway for coprecipitation, has low selectivity for chemical compositions. Collectively, our results demonstrate that coprecipitation plays a crucial role in sequestering both OC and P in aquatic systems, arguing that the formation of ternary OC-Fe-P coprecipitates may be an important pathway for sequestering OC and P over a long term and reducing the internal loading of P in eutrophic lakes.
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