Analysis of network usage and influencing factors among college students returning to a vocational college during COVID-19 epidemic / 中国学校卫生

Objective@#To understand the current situation and influencing factors of Internet addiction among college students after returning to school during the COVID-19 epidemic, and to provide scientific basis for timely intervention measures to adjust the risk factors of Internet addiction.@*Methods@#A cluster sampling method was adopted to conduct a questionnaire survey among 2 700 college students who firstly returned to college using general condition questionnaire and Internet Addiction scale.@*Results@#The detection rate of Internet addiction disorder was 32.4% among returning college students, moreover, the detection rate of Internet addiction in male students(36.0%) was higher than that in female students (31.2%) (χ 2=5.42,P<0.05). The degree of Internet addiction was negatively correlated with the physical health score (r-s=-0.20) and mental health score (r-s=-0.24) of college students (P<0.01). Multivariate Logistic regression analysis showed that compared with introversion, neutral (OR=0.67, 95%CI=0.55-0.82) and extroverted college students (OR=0.59, 95%CI=0.48-0.74) were protective factors for Internet addiction; compared with no exercise, physical exercise ≥3 times or more per week (exercise 3-4 times：OR=0.67, 95%CI=0.51-0.87; ≥5 times：OR=0.67, 95%CI=0.50-0.90) were the protective factors for Internet addiction among college students; family loss during the epidemic was a risk factor for Internet addiction among college students (OR=1.34, 95%CI=1.12-1.60); the risk of Internet addiction was 2.13 times higher for college students who actively sought psychological help than for those who did not seek psychological help (95%CI=1.14-3.96); college students who did not want to go back to school had 1.50 times the risk of Internet addiction as those who did (95%CI=1.26-1.77).@*Conclusion@#The current situation of college students online behaviors during COVID-19 is not optimistic, and should arouse sufficient attention from society and universities. In addition, college students returning to school should take more physical exercises and psychological counseling to detect and intervene in psychological problems in time, reduce their psychological burden, and enhance their psychological quality.

Effect of telehealth interventions on major cardiovascular outcomes: a meta-analysis of randomized controlled trials.

BACKGROUND: Telehealth interventions (THI) were associated with lower levels of cardiovascular risk factors in adults, whereas the effect of THI on cardiovascular disease (CVD) still remains controversial. A meta-analysis was conducted to summarize the evidence from randomized controlled trials (RCT) which investigated potential impact of THI on the incidence of CVD in patients with or without prior CVD. METHODS: PubMed, EmBase, and the Cochrane Library were searched to identify RCTs to fit our analysis through December 2016. Relative risk (RR) with its 95% confidence interval (CI) was used to measure the effect of THI using a random-effect model. Sensitivity analysis, subgroup analysis, heterogeneity tests, and tests for publication bias were also conducted. RESULTS: Eight RCTs were included and with a total of 1635 individuals. The summarized results indicated that participants who received THI showed a significant reduction of the CVD incidence as compared with usual care (RR: 0.59; 95% CI: 0.47-0.74; P < 0.001). Furthermore, the effect of THI was greater in patients with history of CVD (RR: 0.55; 95% CI: 0.44-0.70; P < 0.001) than in patients without history of CVD (RR: 0.99; 95% CI: 0.51-1.94; P = 0.977). Sensitivity analysis suggested that the intervention effect persisted and the conclusion was not changed. Subgroup analysis indicated mean age, study quality might play an important role on the risk of CVD. CONCLUSIONS: The findings of this study indicated THI could reduce the recurrence of CVD. Further large-scale trials are needed to verify the effect of THI on CVD in healthy individuals.

Evaluation of 2-stage Treatment for Cervical Dorsal Rami Entrapment Syndrome: A Randomized, Controlled Trial.

OBJECTIVES: To evaluate the effectiveness of a 2-stage nonoperative treatment for patients with cervical dorsal rami entrapment syndrome. MATERIALS AND METHODS: The study included 66 patients diagnosed with cervical dorsal rami entrapment syndrome randomized to an experimental group (n=33) and control group (n=33). The experimental group was treated with additional diagnostic block if regular 2 weeks medication was not effective. The control group only received nonsteroidal anti-inflammatory drugs for 2 weeks. A visual analog scale (VAS) and pain treatment satisfaction scale (PTSS) were used to assess pain. Muscle power in the upper limbs was also assessed. The registration number of this study is ChiCTR-IIR-15007565. RESULTS: The VAS scores of the experimental group were significantly lower at 2, 4, and 6 months after treatment compared with baseline and the VAS scores of the control group (all P<0.001). The PTSS scores of the experimental group were significantly higher at 2, 4, and 6 months after treatment compared with baseline and the PTSS scores of the control group (all P<0.001). Maximal muscle power after treatment was significantly greater in the experimental group compared with the control group for shoulder abduction (P<0.001), thumb pinch force (P=0.001), and grasp (P<0.001). CONCLUSIONS: The results suggest that the 2-stage treatment is effective for patients with cervical dorsal rami entrapment syndrome.

Morphology and concentration of smoke from fluorinated ethylene propylene wire insulation in microgravity under forced airflow.

The production of smoke particles from the jet bursting flame caused by overheating fluorinated ethylene propylene (FEP) wire insulations was investigated. Experiments examining the morphology and volume fraction of the fractal smoke particle aggregates with forced airflow were conducted in a 3.5s drop tower. Gravity level and forced flow were shown to have significant hydrodynamic effects on the pathlines and fractal aggregation of the smoke particles, thus the residence time-dependent flame shape, particle size and concentration have obvious changes. For cases in still air, compared with normal gravity, the jet flame in microgravity has a spherical shape, the mean primary particle and aggregate gyration radius are bigger due to longer residence time, but the fractal dimension maintains at about 1.79, similar to that in the normal gravity level; the calculated smoke volume fraction is also bigger. For cases with force flow in microgravity, the mean primary particle diameter, the mean aggregate gyration radius, and soot volume fraction all decrease with increasing forced flow due to decreasing residence time.

A dual-potential electrochemiluminescence ratiometric approach based on graphene quantum dots and luminol for highly sensitive detection of protein kinase activity.

A novel Au NP mediated dual-potential ECL ratiometric approach for highly sensitive protein kinase activity and inhibition assay has been developed based on the simultaneous decrease of cathodic ECL from GQDs and enhancement of anodic ECL from luminol in the same bioanalysis.

One-pot synthesis of GO/AgNPs/luminol composites with electrochemiluminescence activity for sensitive detection of DNA methyltransferase activity.

DNA methyltransferases catalyze the transfer of a methyl group from S-adenosylmethionine to the target adenine or cytosine, eventually inducing the DNA methylation in both prokaryotes and eukaryotes. Herein, we developed a novel electrochemiluminescence biosensor to quantify DNA adenine methylation (Dam) methyltransferase (MTase) employing signal amplification of GO/AgNPs/luminol composites to enhance the assay sensitivity. The method was developed by designing a capture probe DNA, which was immobilized on gold electrode surface, to hybridize with azide complementary DNA to form the azide-terminated dsDNA. Then, alkynyl functionalized GO/AgNPs/luminol composites as the signal probe were immobilized to azide-terminated dsDNA modified electrode via click chemistry, resulting in a high electrochemiluminescence (ECL) signal. Once the DNA hybrid was methylated (under catalysis of Dam MTase) and further cleaved by Dpn I endonuclease (a site-specific endonuclease recognizing the duplex symmetrical sequence of 5'-G-Am-T-C-3'), GO/AgNPs/luminol composites release from the electrode surface to the solution, leading to significant reduction of the ECL signal. The change of the ECL intensity is related to the methylation status and MTase activity, which forms the basis of MTase activity assay and site-specific methylation determination. This novel strategy can be further used as a universal method for other transferase determination by designing various transferase-specific DNA sequences. In addition, this method can be used for the screening of antimicrobial drugs and has a great potential to be further applied in early clinical diagnosis.

A versatile polydopamine platform for facile preparation of protein stationary phase for chip-based open tubular capillary electrochromatography enantioseparation.

A novel, simple, and economical method for the preparation of chiral stationary phases for chip-based enantioselective open tubular capillary electrochromatography (OT-CEC) using polydopamine (PDA) coating as an adhesive layer was reported for the first time. After the poly(dimethylsiloxane) (PDMS) microfluidic chip was filled with dopamine (DA) solution, PDA film was gradually formed and deposited on the inner wall of microchannel as permanent coating via the oxidation of DA by the oxygen dissolved in the solution. Due to possessing plentiful catechol and amine functional groups, PDA coating can serve as a versatile multifunctional platform for further secondary reactions, leading to tailoring of the coatings for protein bioconjugation by the thiols and amines via Michael addition or Schiff base reactions. Bovine serum albumin (BSA), acting as a target protein, was then stably and homogeneously immobilized in the PDA-coated PDMS microchannel to fabricate a novel protein stationary phase. Compared with the native PDMS microchannels, the modified surfaces exhibited much better wettability, more stable and enhanced electroosmotic mobility, and less nonspecific adsorption. The water contact angle and electroosmotic flow of PDA/BSA-coated PDMS substrate were measured to be 44° and 2.83×10(-4)cm(2)V(-1)s(-1), compared to those of 112° and 2.10×10(-4)cm(2)V(-1)s(-1) from the untreated one, respectively. Under a mild condition, d- and l-tryptophan were efficiently separated with a resolution of 1.68 within 130s utilizing a separation length of 37mm coupled with in-column amperometric detection on the PDA/BSA-coated PDMS microchips. This present versatile platform, facile conjugation of biomolecules onto microchip surfaces via mussel adhesive protein inspired coatings, may offer new processing strategies to prepare a biomimetic surface design on microfluidic chips, which is promising in high-throughput and complex biological analysis.

Preparation of polynorepinephrine adhesive coating via one-step self-polymerization for enantioselective capillary electrochromatography coupled with electrogenerated chemiluminesense detection.

For the first time, a simple and 'green' approach based on one-step strategy was designed and developed for the modification of a fused-silica capillary with polynorepinephrine (PNE) to separate amino acid enantiomers using capillary electrochromatography coupled with electrogenerated chemiluminescence detection (CEC-ECL). Norepinephrine (NE) was filled into capillary to generate PNE coating on the surface of capillary as permanent coating via the oxidation of NE by oxygen dissolvable in the solution. The formation of the PNE coating was characterized by scanning electron microscopy, UV-vis spectra and contact angle measurements. Compared with the native capillary, the modified capillary had much better wettability, less nonspecific adsorption toward amino acids, and the enantiomers of histidine, phenylalanine, and valine samples received baseline separation with the resolution factors of 1.6, 1.8 and 1.6, respectively, utilizing a separation length of 40 cm of the capillary coupled with ECL detection on the PNE-coated capillary.

A novel open-tubular capillary electrochromatography using ß-cyclodextrin functionalized graphene oxide-magnetic nanocomposites as tunable stationary phase.

Chip-based enantioselective open-tubular capillary electrochromatography (OT-CEC) with ß-cyclodextrin (ß-CD) conjugated graphene oxide-magnetic nanocomposites (GO/Fe(3)O(4) NCs) as stationary phase was developed. GO/Fe(3)O(4) NCs with high magnetic responsivity, excellent solubility and high dispersibility in water were prepared through a facile and controllable in situ chemical deposition strategy. ß-CD was then adsorbed onto the GO/Fe(3)O(4) surface to form GO/Fe(3)O(4)/ß-CD NCs which were localized to the pre-nominated position in polydimethylsiloxane (PDMS) microchannels with the help of magnets. The resultant GO/Fe(3)O(4)/ß-CD NCs not only have the magnetism of Fe(3)O(4) NPs that make them easily manipulated by an external magnetic field, but also have the larger surface which can incorporate much more chiral selector molecules. In addition, the successful ß-CD decorations endowed GO/Fe(3)O(4)/ß-CD NCs with excellent wettability and led to enhanced stability against high ionic strength. Compared with the native PDMS microchip, the modified surfaces exhibited more stable and suppressed electroosmotic mobility, and less nonspecific adsorption toward analytes. Successful baseline separation of tryptophan enantiomers was achieved in less than 50s with a resolution factor of 1.65 utilizing a separation length of 37 mm coupled with in-column amperometric detection. Factors that influence the chiral separation resolution were examined. Under the optimized conditions, the proposed modified chip revealed adequate repeatability concerning run-to-run and day-to-day. These results show that the use of GO/Fe(3)O(4)/ß-CD NCs within microfluidic channels hold great promise for a variety of analytical schemes.

[Study on the solid state transformation of PET/nano-CaCO3 composites by variable temperature FTIR spectroscopy].

Solid state transformation of crude poly (ethylene terephthalate)(PET) and PET/nano-CaCO3 (MPET) composites were studied by variable temperature FTIR spectroscopy during the heating process from 40 to 250 degrees C. The effects of nanometer calcium carbonate(nano-CaCO3) on the solid state transformation and crystal correlation bands of MPET composites were analyzed by the curves of the ratio of 1 342 and 1 410 cm(-1) absorbency(A1 342/A1 410) with temperature increasing, and together with DSC curves in the same condition. The results showed that the crystallization degrees of crude PET and MPET are obviously different in this condition by adding nano-CaCO3 particles as inhomogeneous nucleating agents.

Microchip CE analysis of amino acids on a titanium dioxide nanoparticles-coated PDMS microfluidic device with in-channel indirect amperometric detection.

In this paper, titanium dioxide nanoparticles (TiO(2) NPs) were employed to construct a functional film on PDMS microfluidic channel surface, which was formed by sequentially immobilizing poly(diallyldimethylammonium chloride) and TiO(2) NPs on PDMS surface by layer-by-layer assembly technique. The modified PDMS microchip exhibited a decreased and stable EOF, which was favorable for the separation of biomolecules with similar migration times. Arginine, phenylalanine, serine and threonine were used as model analytes to evaluate the performance of the modified microchip. The four amino acids were efficiently separated within 100 s in a 3.7 cm long separation channel and successfully detected on the carbon fiber electrode in conjunction with in-channel indirect amperometry. Resolutions and theoretical plate numbers of the analytes were considerably enhanced in the presence of TiO(2) NPs. The modified microchip demonstrated excellent stability and reproducibility with improved RSDs of migration times and peak currents for run-to-run, day-to-day and chip-to-chip analyses, respectively. Variables influencing the separation efficiency and amperometric response, including injection and separation voltage, the working electrode position and buffer concentration, were optimized in detail.

Bis(4-ferrocenylbenzoato-κO)tetra-kis(methanol-κO)cadmium(II).

The complete mol-ecule of the title compound, [CdFe(2)(C(5)H(5))(2)(C(12)H(8)O(2))(2)(CH(4)O)(4)], is generated by crystallographic twofold symmetry, with the Cd atom lying on the rotation axis. The Cd atom is coordinated by the O atoms of the four methanol mol-ecules and by the O atoms of the two carboxyl-ate anions (the latter in cis geometry), resulting in a distorted CdO(6) octa-hedron. The phenyl-ene ring is almost coplanar with its adjacent cyclo-penta-dienyl ring [dihedral angle = 8.2 (2)°]. The uncoordin-ated carboxyl-ate O atom acts as acceptor to two O-H⋯O hydrogen bonds from the methanol mol-ecules, giving rise to a layered network.

[Spectral analysis of the effect of different polymerization potential on electrosynthesized poly (5-nitroindole) films].

High quality poly (5-nitroindole) (PNI) films can be synthesized electrochemically by direct anodic oxidation of 5-nitroindole (NI) in boron trifluoride diethyl etherate (BFEE) at different polymerization potential in the range of 1.23-2.23 V (vs. SCE). To the best of our knowledge, this is the first time that high quality polymer films of nitro group substituted conducting polymers were electrodeposited. The oxidation onset potential of NI was only 1.04 V vs. SCE in this medium. Chronoamperometric response of NI, FTIR and 1H NMR indicated that the polymerization potential had a great effect on the quality of PNI films. Lower potential is helpful for the electrochemical polymerization of NI and the extension of the conjugation length of PNI. On the other hand, a higher potential led to side reactions and poor polymer film quality. The structural characterization of PNI films by FTIR and 1H NMR indicated that the electrochemical polymerization of NI occurred at C2 and C3 positions.