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  • Author or Editor: Hui Wu x
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Background and aims

Previous research shows that empathy can be one of the potential protective factors for Internet gaming disorder (IGD), yet the complex relationships between multidimensional factors of empathy and IGD remain understudied. Thus, a major question moving forward is to resolve the mixed empirical data by examining the specific contributions of empathy components. In this study, we disentangle the effects of cognitive component (i.e., perspective taking) and affective component (i.e., empathic concern and personal distress) on IGD symptoms and propose affect-oriented mediation pathways between them.

Methods

We surveyed a large sample (N = 3,348) of Chinese vocational school students, one of the most vulnerable groups to online gaming addiction.

Results

Our structural equation modeling results revealed that only personal distress, but not empathic concern or perspective taking, positively predicted IGD symptoms. However, empathic concern and personal distress were negatively and positively predicted gaming motive of escape from reality, respectively, which in turn predicted IGD symptoms. Furthermore, we found an indirect effect of perspective taking on IGD through empathic concern and then gaming motive of escape from reality.

Discussion and conclusion

The findings underscore the importance of separating the affective and cognitive components to understand the complex relationships between the empathy and IGD, and support our theorizing of the affect-oriented mediation mechanism.

Open access

Abstract

Let H n be the n-th harmonic number and let v n be its denominator. It is known that v n is even for every integer n>=2. In this paper, we study the properties of H n and prove that for any integer n, v n = e n(1+o(1)). In addition, we obtain some results of the logarithmic density of harmonic numbers.

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Abstract  

Effects of pH, Eu(III) concentration, ionic strength, temperature and humic acid (HA) on Eu(III) sorption to iron oxides were investigated in detail. The sorption of Eu(III) to iron oxides was significantly dependent on pH and weakly dependent on ionic strength, and higher temperature was gainful to Eu(III) sorption. In the presence of HA, Eu(III) sorption was enhanced significantly at low pH; whilst obvious negative effect was observed in higher pH range. Below 12 mg/L HA, HA could obviously enhanced Eu(III) sorption to iron oxides, nevertheless Eu(III) sorption decreased steeply with increasing HA while HA exceeded 12 mg/L. The results were helpful for understanding radionuclides behaviors in natural environment.

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Abstract

New types of S2O8 2−/Al-x wt%Ce–Zn–O solid acid catalysts were prepared by the sol–gel method. Their catalytic performances for the synthesis of n-butyl acetate from acetic acid and n-butanol were investigated. The characterization of prepared catalysts was performed using XRD, IR, TG-DSC and SEM. The experimental results showed that the S2O8 2−/Al-2.5 wt%Ce–Zn–O solid acid catalyst exhibited an optimal esterification performance with 98.71% esterification efficiency under the optimum synthesis conditions. Moreover, the S2O8 2−/Al-2.5 wt%Ce–Zn–O solid acid catalyst retained its high activity with above 95% esterification efficiency after being used repeatedly for seven times, which indicated that the S2O8 2−/Al-2.5 wt%Ce–Zn–O solid acid catalyst had excellent stability.

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Abstract

Background and aims

Mobile phone addiction (MPA) is frequently reported to be correlated with anxiety, depression, stress, impulsivity, and sleep quality among college students. However, to date, there is no consensus on the extent to which those factors are correlated with MPA among college students. We thus performed a meta-analysis to quantitatively synthesize the previous findings.

Methods

A systematic review and meta-analysis was conducted by searching PubMed, Embase, Cochrane Library, Wanfang, Chinese National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and Chinese Biological Medicine (CBM) databases from inception to August 1, 2020. Pooled Pearson's correlation coefficients between MPA and anxiety, depression, impulsivity, and sleep quality were calculated by R software using random effects model.

Results

Forty studies involving a total of 33, 650 college students were identified. Weak-to-moderate positive correlations were found between MPA and anxiety, depression, impulsivity and sleep quality (anxiety: summary r = 0.39, 95% CI = 0.34–0.45, P < 0.001, I 2 = 84.9%; depression: summary r = 0.36, 95% CI = 0.32–0.40, P < 0.001, I 2 = 84.2%; impulsivity: summary r = 0.38, 95% CI = 0.28–0.47, P < 0.001, I 2 = 94.7%; sleep quality: summary r = 0.28, 95% CI = 0.22–0.33, P < 0.001, I 2 = 85.6%). The pooled correlations revealed some discrepancies when stratified by some moderators. The robustness of our findings was further confirmed by sensitivity analyses.

Conclusions

The current meta-analysis provided solid evidence that MPA was positively correlated with anxiety, depression, impulsivity, and sleep quality. This indicated that college students with MPA were more likely to develop high levels of anxiety, depression, and impulsivity and suffer from poor sleep quality. More studies, especially large prospective studies, are warranted to verify our findings.

Open access
Authors: Feng Wu, Xiuli Zhao, Shumin Wang, Hui Zhou, Shaojie Guo, Siyang Ni, Bo Yang, Lihua Zhang and Xinde Xu

The aim of this study was to develop and validate a HPLC-MS/MS assay to determine the lutein concentration in plasma samples of human and SD rats. Organic solvent was used for lutein extraction. The extract was injected into a HPLC-MS/MS system. Reversed phase chromatography was performed on a C18 column in gradient mode. Lutein and internal standard (phenytoin sodium) were identified in atmospheric pressure chemical ionization mode using ion transitions of m/z 567.5>549.4 and 205.2>110.8, respectively. The lutein quantification assay was linear over concentrations ranging from 4 to 500 ng/mL. The lower limit of quantification was 4 ng/mL with satisfactory precision and accuracy. The assay presented acceptable intra and inter-batch precision (RSD%) and accuracy (RE%) <8.16% in SD rat plasma and <12.80% in human plasma. The extraction recovery ranged from 50.94 to 60.90% in SD rat plasma and 68.73% in human plasma. The matrix effect for lutein was acceptable and had minimal influence on the results. The method was then applied to determine the lutein concentrations in human plasma after a single oral dose of 20mg lutein. The method described is rapid, selective, sensitive and reproducible. This method can be used for both pharmacokinetic studies and therapeutic drug monitoring purposes.

Open access
Authors: Zong-Xi Cao, Pei-Rong Jiao, Yu-Mao Huang, Hong-Yang Qin, Liu-Wu Kong, Quan-Hui Pan, Yi-Min He and Gui-Hong Zhang

To understand the genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) in South China, we collected 231 clinical samples from pigs with suspected PRRSV infection in Guangdong between 2007 and 2009. We found that 74 of 231 samples were positive by RT-PCR. The PCR products of the ORF5 gene of 35 isolates from different farms were sequenced and their DNA sequences were compared to 23 other PRRSV isolates in the GenBank. We found that the nucleotide similarity among all South China isolates ranged from 87.6% to 100%, and all belonged to the North American genotype. Most of them were classified into subgenotype I, but the rest mapped to subgenotypes III, V or VI. Those in subgenotypes I and III were found to be highly variable in the primary neutralising epitope (PNE) with a specific amino acid mutation (F39/L39→I39), and a few isolates in subgenotypes I and III isolates also had a mutation at L41 (L41→S41). PRRSV isolates in subgenotypes III, V and VI had less potential glycosylation sites than those in subgenotype I. Our data contribute to the understanding of molecular variation of PRRSV in South China.

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Exploring antibiotic resistant mechanism by microcalorimetry

Determination of thermokinetic parameters of metallo-β-lactamase L1 catalyzing penicillin G hydrolysis

Authors: Hui-Zhou Gao, Qi Yang, Xiao-Yan Yan, Zhu-Jun Wang, Ji-Li Feng, Xia Yang, Sheng-Li Gao, Lei Feng, Xu Cheng, Chao Jia and Ke-Wu Yang

Abstract

In an effort to probe the reaction of antibiotic hydrolysis catalyzed by B3 metallo-β-lactamase (MβL), the thermodynamic parameters of penicillin G hydrolysis catalyzed by MβL L1 from Stenotrophomonas maltophilia were determined by microcalorimetric method. The values of activation free energy ΔG θ are 88.26, 89.44, 90.49, and 91.57 kJ mol−1 at 293.15, 298.15, 303.15, and 308.15 K, respectively, activation enthalpy ΔH θ is 24.02 kJ mol−1, activation entropy ΔS θ is −219.2511 J mol−1 K−1, apparent activation energy E is 26.5183 kJ mol−1, and the reaction order is 1.0. The thermodynamic parameters reveal that the penicillin G hydrolysis catalyzed by MβL L1 is an exothermic and spontaneous reaction.

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Exploring antibiotic resistant mechanism by microcalorimetry II

Determination of thermokinetic parameters of imipenem hydrolysis with metallo-β-lactamase ImiS

Authors: Xia Yang, Lei Feng, Kang-Zhen Xu, Hui-Zhou Gao, Chao Jia, Cheng-Cheng Liu, Jian-Min Xiao, Le Zhai, Li-Sheng Zhou and Ke-Wu Yang

Abstract

In an effort to understand the reaction of antibiotic hydrolysis with B2 metallo-β-lactamases (MβLs), the thermodynamic parameters of imipenem hydrolysis catalyzed by metallo-β-lactamase ImiS from Aeromonas veronii bv. sobria were determined by microcalorimetric method. The values of activation free energy are 86.400 ± 0.043, 87.543 ± 0.034, 88.772 ± 0.024, and 89.845 ± 0.035 kJ mol−1 at 293.15, 298.15, 303.15, and 308.15 K, respectively, activation enthalpy is 18.586 ± 0.009 kJ mol−1, activation entropy is −231.34 ± 0.12 J mol−1 K−1, apparent activation energy E is 21.084 kJ mol−1, and the reaction order is 1.5. The thermodynamic parameters reveal that the imipenem hydrolysis catalyzed by metallo-β-lactammase ImiS is an exothermic and spontaneous reaction.

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Authors: Cui -Mei Yin, Yang -Hui Kong, Zi -Ru Liu, Cheng -Yun Wu, De -Hou Ren, Ming -An He and Hong -Fu Xue

Thermal dissociation reactions and mechanism of complexes of rare earth(iii) nitrates with the crown ether benzo-15-crown-5 were investigated by means of TG-DTG, DSC, DTA and IR technique. The results have shown that the dissociation processes of the complexes consist of several steps, one of which is a fast decomposition reaction. The fast decomposition peak temperatures (DSC) of all the complexes of the lanthanides (except Pm and Tm) decrease regularly with increasing atomic number. Moreover, values of the enthalpy change of desolvation, fast and the fourth step of decomposition and the apparent activation energies of fast and the fourth step of decomposition were obtained.

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