Depression and Loneliness as Mediators Between Social Support and Mobile Phone Addiction.

BACKGROUND: Mobile phone addiction among adolescents has attracted a lot of attention in recent years. Previous researches revealed a significant relation between low social support and addiction. This study aim to investigated the association between social support and mobile phone addiction, and the mediating effects of depression and loneliness. SUBJECTS AND METHODS: A total of 1,400 Chinese adolescents aged from 12 to 23 years old was recruited from two middle schools and a college in Hunan Province, China. Participates were selected using the cluster random sampling method. They completed the Mobile Phone Addiction Index, the Self-Rating Depression Scale, the UCLA Loneliness Scale, and the Adolescent Social Support Scale. The study analyzed the correlations between the study variables and the mediating role of depression and loneliness in the relationship between social support and mobile phone addiction. RESULTS: There were significant negative correlation between social support and depression, loneliness, and mobile phone addiction (p<0.001). Both depression and loneliness demonstrated significant positive correlation with mobile phone addiction (p<0.001). Structural equation modeling revealed that both depression and loneliness mediated the association between social support and mobile phone addiction (p<0.001). Depression and loneliness sequentially mediated the association between social support and mobile phone addiction (p<0.001). However, the relation between social support and mobile phone addiction was not significant (p>0.05). CONCLUSIONS: Social support can lower levels of mobile phone addiction among adolescents by reducing depression and loneliness. This study sheds light on the underlying mechanisms between social support and mobile phone addiction, which has profound implications for the prevention and interventions of adolescent problematic mobile phone use.

Perceived stress and mobile phone addiction among college students during the 2019 coronavirus disease: The mediating roles of rumination and the moderating role of self-control.

This present study aimed to examine the mediating role of rumination and the moderating role of self-control in the link between perceived stress and mobile phone addiction during the COVID-19 epidemic. A total of 628 college students completed Depression-Anxiety-Stress Scale, Smartphone Addiction Scale, Ruminative Responses Scale and Self-Control Scale. Mediation analysis highlighted that rumination mediated the association between perceived stress and mobile phone addiction. Moderated mediation analysis indicated that the indirect association between perceived stress and mobile phone addiction were moderated by self-control. Between the COVID affected group and the unaffected group, some differences also be observed in the moderating effect of self-control. This study emphasize the importance of rumination and self-control in understanding the possible mechanisms underlying the relationship between perceived stress and mobile phone addiction, which can be used to develop interventions to reduce the problematic behavior among college students during the COVID-19 pandemic.

Efficient Bioproduction of Indigo and Indirubin by Optimizing a Novel Terpenoid Cyclase XiaI in Escherichia coli.

Blue indigo dye, an important natural colorant, is used for textiles and food additives worldwide, while another red isomer, indirubin, is the major active ingredient of a traditional Chinese medicine named "Danggui Longhui Wan" for treating various diseases including granulocytic leukemia, cancer, and Alzheimer's disease. In this work, we constructed a new and highly efficient indigoid production system by optimizing a novel terpenoid cyclase, XiaI, from the xiamycin biosynthetic pathway. Through introducing the flavin-reducing enzyme Fre, tryptophan-lysing and -importing enzymes TnaA and TnaB, and H2O2-degrading enzyme KatE and optimizing the fermentation parameters including temperature, the concentration of isopropyl-ß-d-thiogalactopyranoside, and feeding of the l-tryptophan precursor, the final maximum productivity of indigoids by the recombinant strain Escherichia coli BL21(DE3) (XiaI-Fre-TnaAB-KatE) was apparently improved to 101.9 mg/L, an approximately 60-fold improvement to that of the starting strain E. coli BL21(DE3) (XiaI) (1.7 mg/L). In addition, when the fermentation system was enlarged to 1 L in the flask (feeding with 5 mM tryptophan and 10 mM 2-hydroxyindole), the indigoid productivity further increased to 276.7 mg/L at 48 h, including an indigo productivity of 26.0 mg/L and an indirubin productivity of 250.7 mg/L, which has been the highest productivity of indirubin so far. This work provided a basis for the commercial production of bio-indigo and the clinical drug indirubin in the future.

Ultrasensitive and selective detection of Staphylococcus aureus using a novel IgY-based colorimetric platform.

To develop a specific method for the detection of S. aureus, chicken anti-protein A IgY was adopted for specifically capturing S. aureus, depending on the specific recognition of staphylococcal protein A (SPA) by chicken anti-protein A IgY, which can eliminate the interference from protein G-producing Streptococcus. HRP labeled IgG, Fc region of which has a high affinity towards SPA, was paired with IgY for the colorimeter analysis of the system. By optimizing the system, a super-low detection limit of 11 CFU of S. aureus in 100 µL PBS without enrichment, with a linear range from 5.0 × 102 CFU mL-1 to 5.0 × 104 CFU mL-1 was obtained. The entire assay was accomplished in less than 90 min and no cross-reactivity with the other tested bacterial species was observed. Moreover, the developed assay has been applied for the detection of S. aureus in three different types of real samples (sodium chloride injection, apple juice and human urine) with satisfactory results. To the best of our knowledge, it is the first time to report using chicken anti-protein A IgY and any IgG to detect S. aureus based on the dual-recognition mode of SPA. The novel method opened up a way for monitoring S. aureus in food samples with high sensitivity, specificity and simple operation.