Latent profile and network analysis of risk perception among a sample of Chinese university students during the COVID-19 pandemic: a cross-sectional and longitudinal study

BackgroundThe risk perception of contracting COVID-19 is an important topic for assessing and predicting COVID-19 infection and health education during the pandemic. However, studies that use latent profiles and network analysis together to measure the risk perception of COVID-19 are rare. Therefore, this study combined latent profile analysis and network analysis to measure risk perception toward COVID-19 among Chinese university students through a cross-sectional and longitudinal study.MethodsA sample of 1,837 Chinese university students (735 males, 40%) completed the cross-sectional study with an eight-item risk perception questionnaire in January 2020, while 334 Chinese university students (111 males, 33.2%) completed the longitudinal study at three time points.ResultsA two-class model including a low risk perception class (n = 1,005, 54.7%) and a high risk perception class (n = 832, 45.3%) was selected for the cross-sectional study. Nodes rp6 (“Average people have chances of contracting COVID-19'') and rp7 (“Average people worry about catching COVID-19”) had the strongest edge intensity (r = 0.491), while node rp5 (“The COVID-19 outbreak affects the whole country”) had the highest strength centrality in the cross-sectional study. The risk perception of contracting COVID-19 decreased continuously at the three time points. Moreover, the network structures and global strengths had no significant differences in the longitudinal study.ConclusionsThe risk perception of contracting COVID-19 decreased continually during the COVID-19 pandemic, which indicated the importance of cultural influence and effective government management in China. In addition, university students displayed strong trust and confidence in the government's ability to fight COVID-19. The results indicate that the government should take strong measures to prevent and intervene in various risks and reinforce the public's trust through positive media communications

Analysis of 22 Elements in Milk, Feed, and Water of Dairy Cow, Goat, and Buffalo from Different Regions of China

The objectives of this study were to measure the concentrations of elements in raw milk by inductively coupled plasma-mass spectrometry (ICP-MS) and evaluate differences in element concentrations among animal species and regions of China. Furthermore, drinking water and feed samples were analyzed to investigate whether the element concentrations in raw milk are correlated with those in water and feed. All samples were analyzed by ICP-MS following microwave assisted acid digestion. The mean recovery of the elements was 98.7 % from milk, 103.7 % from water, and 93.3 % from a certified reference material (cabbage). Principal component analysis results revealed that element concentrations differed among animal species and regions. Correlation analysis showed that trace elements Mn, Fe, Ni, Ga, Se, Sr, Cs, U in water and Co, Ni, Cu, Se, U in feed were significantly correlated with those in milk (p < 0.05). Toxic and potential toxic elements Cr, As, Cd, Tl, Pb in water and Al, Cr, As, Hg, Tl in feed were significantly correlated with those in milk (p < 0.05). Results of correlation analysis revealed that elements in water and feed might contribute to the elements in milk

Increased Ion Conductivity in Composite Solid Electrolytes With Porous Co3O4 Cuboids

Compared with the fagile ceramic solid electrolyte, Li-ion conducting polymer electrolytes are flexible and have better contact with electrodes. However, the ionic conductivity of the polymer electrolytes is usually limited because of the slow segment motion of the polymer. In this work, we introduce porous Co3O4 cuboids to Poly (Ethylene Oxide)-based electrolyte (PEO) to investigate the influence of these cuboids on the ionic conductivity of the composite electrolyte and the performance of the all-solid-state batteries. The experiment results showed the porous cuboid Co3O4 fillers not only break the order motion of segments of the polymer to increase the amorphous phase amount, but also build Li+ continuous migration pathway along the Co3O4 surface by the Lewis acid-base interaction. The Li+ conductivity of the composite polymer electrolyte reaches 1.6 × 10−4 S cm−1 at 30°C. The good compatibility of the composite polymer electrolyte to Li metal anode and LiFePO4 cathode ensures good rate performance and long cycle life when applying in an all-solid-state LiFePO4 battery. This strategy points out the direction for developing the high-conducting composite polymer electrolytes for all-solid-state batteries

Investigation of field emission characteristics and microstructure of nickel-doped DLC nanocomposite films by electrochemical deposition

The as-obtained nickel doped DLC films by the electrochemical process demonstrated the surface morphology of a nano-tip transformed to bumps with increasing nickel compound concentration in the electrolyte, simultaneously the sp 2-C content greatly increased. Nickel was incorporated into highly cross-linked amorphous carbon matrix, forming the typical nanocrystalline/ amorphous composite microstructure, which was in the form of element nickel, nickel hydroxide, and nickel oxide. Field emission performance showed that nickel incorporation effectively lowers the threshold field from 9.9 to 8.4 V/μm at the electron emission current density of 1 μA/cm 2, and greatly increased the emission current density from 21.88 to 163.89 μA/cm 2 under 12.455 V/μm for DLC film. The Raman and XPS measurements of the as-deposited films suggested that spatially localized conduction channels formed by the graphite-like sp 2-carbon and metallic particles might be responsible for the electron emission in nickel-doped DLC films

Research on Symmetry of Micromachined Silicon Resonant Accelerometer

The Micromachined Silicon Resonant Accelerometer (MSRA) is a micro- accelerometer with potential high accuracy and is one of development focuses of the silicon inertia sensor. The MSRA mostly adopts the differential structure to inhibit the common-mode error. However, the two resonators of the practical MSRA prototype are not fully symmetric, thus reducing the effect of the differential structure inhibiting the common-mode error. Factors influencing symmetry of the MSRA are studied from the aspects of structure and circuit. Following that, a method to cope with the problem of asymmetry of two resonators through adjustment of the value of the DC driving voltage is put forward to improve the performance of the MSRA

Occurrence of Aflatoxin M1 in Raw Milk from Manufacturers of Infant Milk Powder in China

This survey was performed to investigate the occurrence of aflatoxin M1 (AFM1) contamination of raw milk from manufacturers of infant milk powder in China. A total of 1207 raw milk samples were collected overall from four seasons of 2016 in Northeast China, Northwest China, Northern China, and Central China (11 provinces and one municipality). Results showed that 56 of the 1207 raw milk samples (4.64%) were positive for AFM1, which were obtained from Heilongjiang (two samples), Gansu (one sample), Shaanxi (46 samples), Beijing (one sample), and Hunan (six samples) provinces. None of the raw milk samples from manufacturers of infant milk powder exceeded the Chinese limit (62.5 ng/L) in 2016. Only a few raw milk samples were not suitable for use in infant milk according to EU (European Union) or U.S. infant milk limits. Furthermore, based on this survey and previous studies, it is particularly important to avoid AFM1 contamination in raw milk during the winter

Design of Temperature Sensitive Structure for Micromechanical Silicon Resonant Accelerometer

A micromechanical silicon resonant accelerometer (MSRA) is a potential micro accelerometer with high accuracy. One of the most important factors affecting its performance is temperature. To research the effect of temperature on micromechanical silicon resonant accelerometer, this study based on the original micromechanical silicon resonant accelerometer, designs a chip-level temperature-sensitive structure which a pair of temperature resonators is arranged on both sides of the force resonator of the original accelerometer to ensure symmetry of the MSRA, as well as compares and selects the appropriate structure, fundamental frequency, and size. The ANSYS simulation is used to verify the rationality of the structure design. The MSRA is fabricated using the Deep Dry Silicon on Glass technique and packaged in metal shell, a measurement circuit is designed and a full temperature test is conducted. The results show that the resonant frequency of the temperature resonator is strongly sensitive to temperature changes but not sensitive to acceleration, and that it can reflects temperature change in the package cavity. Therefore, the temperature resonator can achieve accurate temperature measurement of accelerometer and can be used in temperature compensation

<span style="font-variant: small-caps">l</span>-Proline Alleviates Kidney Injury Caused by AFB1 and AFM1 through Regulating Excessive Apoptosis of Kidney Cells

The toxicity and related mechanisms of aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) in the mouse kidney were studied, and the role of l-proline in alleviating kidney damage was investigated. In a 28-day toxicity mouse model, thirty mice were divided into six groups: control (without treatment), l-proline group (10 g/kg body weight (b.w.)), AFB1 group (0.5 mg/kg b.w.), AFM1 (3.5 mg/kg b.w.), AFB1 + l-proline group and AFM1 + l-proline group. Kidney index and biochemical indicators were detected, and pathological staining was observed. Using a human embryonic kidney 293 (HEK 293) cell model, cell apoptosis rate and apoptotic proteins expressions were detected. The results showed that AFB1 and AFM1 activated pathways related with oxidative stress and caused kidney injury; l-proline significantly alleviated abnormal expressions of biochemical parameters and pathological kidney damage, as well as excessive cell apoptosis in the AF-treated models. Moreover, proline dehydrogenase (PRODH) was verified to regulate the levels of l-proline and downstream apoptotic factors (Bax, Bcl-2, and cleaved Caspase-3) compared with the control (p &lt; 0.05). In conclusion, l-proline could protect mouse kidneys from AFB1 and AFM1 through alleviating oxidative damage and decreasing downstream apoptosis, which deserves further research and development