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Acta Chromatographica
Authors:
Mina Luo
,
Huaqiao Ma
,
Xia Liu
, and
Shengxiang Jiang

Summary

A simple and precise high-performance liquid chromatographic (HPLC) method has been developed for analysis of flavonoids in Lamiophlomis rotata. HPLC conditions were optimized. Baseline separation was achieved by use of a binary gradient prepared from 100:0.2 (v/v) water-trifluoroacetic acid (component A), and acetonitrile (component B). The gradient was from 20 to 35% B in 10 min, hold at 35% B for 20 min, then from 35 to 70% B in 10 min. The injection volume was 10 μL, and the detection wavelength was 366 nm. Linearity and precision were investigated. When normal least-squares linear regression (LSLR) was compared with weighted least-squares linear regression (WLSLR), values obtained by use of the latter were much closer to the actual values, over the whole range of concentration, than those obtained by use of the former. WLSLR was therefore used in this work. This HPLC method was successfully used for analysis of the flavonoids in Lamiophlomis rotata and could be effective for quality control of the plant.

Open access

Abstract

Background and aims

During the COVID-19 lockdown, problematic Internet use (PIU) has become a serious issue among residential college students, who remain physically isolated from off-campus society. This study constructs an integrated model to investigate the influencing mechanisms of internal locus of control (LOC) and objective peer effects.

Methods

Residential college students (n = 494) were surveyed from a single department of a Chinese university. An item from the World Value Survey was employed to measure internal LOC, while objective peer effects were assessed via friends’ mutual nominations. Finally, PIU was measured using Young’s Internet Addiction Tests, while a social network analysis and logit regression were combined to estimate various factors’ effects on PIU.

Results

In our sample, the prevalence rate of PIU was 30.6%, and while internal LOC was a protective factor for PIU, its protective role was diluted when exposed to a peer environment with high PIU prevalence. Furthermore, indegree performed contrasting roles on PIU under various network conditions. It acted as a protective factor when exposed to a low prevalence of PIU in a peer environment; however, it became a risk factor when PIU peers were prevalent. Lastly, the protective efficacy of betweenness was activated when individuals had more than one PIU friend.

Discussion and conclusions

Further intervention studies focusing on individuals with a weak internal LOC are recommended during the lockdown. Additionally, interventions that consider the network structures carefully, may enhance the prevention of PIU.

Open access
Acta Chromatographica
Authors:
Chen Cheng
,
Nie Cun-Xi
,
Liang Jing
,
Wang Yong-Qiang
,
Liu Yan-Feng
,
Ge Wen-Xia
, and
Zhang Wen-Ju

A validated high-performance liquid chromatography (HPLC) method has been developed to analyze the (±)-gossypol in the selection of strains of Candida tropicalis culture. Since gossypol was easily degraded and oxidized, the addition of antioxidant NADPH-Na4 and acetone extraction was chosen to prevent gossypol degradation and gradient elution assay was applied to obtain gossypol resolution. Concentrations of gossypol in C. tropicalis ZD-3 culture 20 μg/mL were determined, and concentration–time profiles were observed. Linearity of the gossypol standard curve by HPLC area method was ranged from 0.1 to 20 μg/mL with Y = 26.954 × X − 29.547, R 2 = 0.9991, and n = 3, with limit of detection (LOD) of 50 ng/mL and lower limit of quantification (LLOQ) of 500 ng/mL. The recovery rate is dose-dependent and ranged from 85.3% to 103.5%. It is a rapid and reliable HPLC method for gossypol quantization in microorganism culture which could be applied in solid fermentation in the feed industry.

Open access

Abstract

Background and aims

Nonsuicidal self-injury (NSSI) is highly prevalent in adolescents and is associated with various mental health problems. Repetitive NSSI (R-NSSI), as an extreme manifestation of NSSI, is a growing concern and has been proposed as a behavioral addiction. However, little is known about the potential addictive mechanisms of NSSI. This study aimed to examine the mediating effect of emotion dysregulation and the moderating effect of impulsivity using the Interaction of Person-Affect-Cognition-Execution (I-PACE) model in adolescents who repeatedly engage in NSSI.

Methods

A total of 3,915 adolescents (mean age = 13.21 years, SD = 0.87, 57.6% male) were recruited from three middle schools. Relevant questionnaires were used to evaluate childhood maltreatment, emotion dysregulation, impulsivity, and NSSI. Mediation and moderated mediation analyses were conducted separately for adolescents with occasional NSSI (O–NSSI) and R-NSSI to assess the relationship between childhood maltreatment, emotion dysregulation, impulsivity, and NSSI frequency.

Results

Our study found that childhood maltreatment was directly related to NSSI and indirectly related to NSSI through emotion dysregulation in both the R-NSSI and O–NSSI groups. Furthermore, impulsivity played a moderating role in the relationship between emotion dysregulation and NSSI in the R-NSSI group but not in the O–NSSI group.

Discussion and conclusions

The findings suggest that a high level of impulsivity and a high level of emotion dysregulation may be important risk addictive factors of NSSI through childhood maltreatment. Strengthening the emotion regulation skills and inhibitory control of adolescents with NSSI would be helpful to reduce their self-injury behaviors and maintain their mental health. This finding also supports the validity of the I-PACE model for evaluating R-NSSI.

Open access
Acta Chromatographica
Authors:
Mei-Xia Zhu
,
Sheng-Nan Li
,
Hai-Dan You
,
Bin Han
,
Zhi-Ping Wang
,
Yan-Xi Hu
,
Jin Li
, and
Yu-Feng Liu

High-performance liquid chromatography coupled with photodiode array detection and evaporative light scattering detection (HPLC—DAD—ELSD) was established to determine paeoniflorin and albiflorin simultaneously in Radix Paeoniae Rubra. The assay was performed on a Diamonsil C18 (4.6 mm × 250 mm, 5 μm) column by a gradient elution program with acetonitrile and aqueous formic acid (0.05% v/v) as mobile phase at a flow rate of 1.0 mL min−1. The detection wavelength of DAD was 230 nm, and the evaporator tube temperature of ELSD was set at 110 °C with the nebulizing gas flow rate of 3 L min−1. The temperature of column was kept at 30 °C. The linear ranges of paeoniflorin and albiflorin were within 0.050–1.510 mg mL−1 and 1.007–5.035 mg mL−1. The recoveries of paeoniflorin and albiflorin were 96.2–102.9% and 95.0–102.4%, respectively, while the relative standard deviation (RSD) of them was 0.2–2.5%. This method was quick, simple, accurate, and specific. It could be used for the quality control of Radix Paeoniae Rubra. The proposed approach was expected as a powerful tool for the quality control of Radix Paeoniae Rubra.

Open access