Strong Periodic Tendency of Trivalent Lanthanides Coordinated with a Phenanthroline-Based Ligand: Cascade Countercurrent Extraction, Spectroscopy, and Crystallography.

Phenanthroline-diamide ligands have been reported in the selective separation of actinides over Eu(III); on the contrary, relevant basic coordination chemistry studies are still limited, and extraction under actual application conditions is rarely involved. In this work, N,N'-diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline [Et-Tol-DAPhen (L)] was applied to explore the coordination performance of lanthanides in simulative high-level liquid waste. For the first time, cascade countercurrent extraction was conducted with Et-Tol-DAPhen as the extractant, which reveals the periodic tendency of the extraction efficiency of lanthanides to decrease gradually as the atomic number increases. Comparison of elements with similar radii verifies the hypothesis that the increase in the atomic number leads to a decrease in the ionic radius, thus reducing the coordination and extraction capacity of ligands. Slope analysis, electrospray ionization mass spectrometry, and ultraviolet-visible titration results show that the ligand forms 1:1 and 1:2 complexes with lanthanides and the coordination ability follows the tendency of extraction efficiency, and the first crystal structures of Lns(III) with a phenanthroline-diamide ligand, i.e., [LaL(NO3)3(H2O)] and [LaL2(NO3)2][(NO3)], were obtained, which confirms the conclusions described above. This work promises to enhance our comprehension of the chemical properties of Lns(III) and offer new clues for the design and synthesis of novel separation ligands.

Selective Separation of Am(III)/Eu(III) by the QL-DAPhen Ligand under High Acidity: Extraction, Spectroscopy, and Theoretical Calculations.

Although 1,10-phenanthroline-based ligands have recently shown vast opportunities for the separation of trivalent actinides (Ans(III)) from lanthanides (Lns(III)), the optimization and design of the extractant structure based on the phenanthroline framework remain hotspots for further improving the separation. Following the strategy of hard and soft donor atom combination, for the first time, the quinoline group was attached to the 1,10-phenanthroline skeleton, giving a lipophilic ligand, 2,9-diacyl-bis((3,4-dihydroquinoline-1((2H)-yl)-1),10-phenanthroline (QL-DAPhen)), for Am(III)/Eu(III) separation. In the presence of sodium nitrate, the ligand can effectively extract Am(III) over Eu(III) in HNO3 solution, with the separation factor (SFAm/Eu) ranging from 29 to 44. The coordination chemistry of Eu(III) with QL-DAPhen was investigated by slope analysis, NMR titration, UV-vis titration, Fourier transform infrared spectroscopy, electrospray ionization-mass spectrometry, and theoretical calculations. The experimental results unanimously confirm that the ligand forms both 1:1 and 1:2 complexes with Eu(III), and the stability constants (log ß) of each of the two complexes were obtained. Density functional theory calculations show that the Am-N bonds have more covalent characteristics than the Eu-N bonds in the complexes, which reveals the reason why the ligand preferentially bonds with Am(III). Meanwhile, the thermodynamic analysis reveals that the 1:1 complex is more thermodynamically stable than the 1:2 complex. The findings of this work have laid a solid theoretical foundation for the application of phenanthroline-based ligands in the separation of An(III) from practical systems.

Hydrophilic Sulfonated 2,9-Diamide-1,10-phenanthroline Endowed with a Highly Effective Ligand for Separation of Americium(III) from Europium(III): Extraction, Spectroscopy, and Density Functional Theory Calculations.

The design and development of a water-soluble heterocyclic ligand are believed to be an alternative way for improving the separation efficiency of actinides from lanthanides. Herein, we designed and synthesized a novel hydrophilic multidentate ligand: disulfonated N,N'-diphenyl-2,9-diamide-1,10-phenanthroline (DS-Ph-DAPhen) with soft and hard donor atoms, as a masking agent in aqueous solutions for Am(III) separation. The combination of N,N,N',N'-tetraoctyldiglycolamide in kerosene and DS-Ph-DAPhen in aqueous phases could separate Am(III) from Eu(III) across a range of nitric acid concentrations with very high selectivity. The coordination behaviors of Eu(III) with DS-Ph-DAPhen in aqueous solutions were studied by UV-vis titration, electrospray ionization mass spectrometry, and Fourier transform infrared spectra. The results indicated that Eu(III) ions could form both 1:1 and 1:2 complexes with the DS-Ph-DAPhen ligand in aqueous solution. Density functional theory calculation suggests that there are more covalent characters for Am-N bonds than that for Eu-N bonds in the complexes, which supports the better selectivity of the DS-Ph-DAPhen ligand toward Am(III) over Eu(III). This work demonstrates a feasible alternative approach to separating trivalent actinides from lanthanides with high selectivity.

Effects of bromate on life history parameters, swimming speed and antioxidant biomarkers in Brachionus calyciflorus.

The baking industries and disinfection of tap water released a considerable amount of bromate into surface water, which has been reported as a carcinogenic compound to mammals. Rotifers play an important role in freshwater ecosystems and are model organisms to assess environmental contamination. In the present study, the effects of different concentrations (0.001, 0.01, 0.1, 1, 10, 100 and 200 mg/L) of bromate on the life-table and population growth parameters were investigated in the rotifer Brachionus calyciflorus. The results showed that the 24-h LC50 of bromate to B. calyciflorus was 365.29 mg/L (95%Cl: 290.37-480.24). Treatments with 0.01, 10 and 200 mg/L bromate shorten the reproductive period. High levels of bromate (100 and 200 mg/L) significantly decreased net reproductive rate, intrinsic rate of population increase, life span, mictic rate of B. calyciflorus. To investigate the underlying mechanisms, swimming speed and antioxidative biomarkers were compared between bromate treatments and the control. The results showed that glutathione (GSH) and malondialdehyde (MDA) contents, total superoxide dismutase (T-SOD) and peroxidase (POD) activities decreased significantly in response to bromate exposure and the reasons required further investigation. Treatments with 0.001-200 mg/L bromate all significantly reduced swimming linear speed to rotifer larvae and treatments with 100-200 mg/L bromate significantly suppressed the swimming linear speed of adult rotifer. These changes would reduce filtration of algal food and could explain the decreased survival and reproduction. Overall, bromate may not show acute toxicity to rotifers, but still have potential adverse effects on rotifer behavior, which may then influence the community structure in aquatic ecosystems.

Selective Separation and Coordination of Europium(III) and Americium(III) by Bisdiglycolamide Ligands: Solvent Extraction, Spectroscopy, and DFT Calculations.

Diglycolamide-based ligands have recently received increased attention due to their outstanding affinity for trivalent actinides and lanthanides. The structure optimization of the ligands, however, still remains a hot topic to achieve better extraction performance. In this work, we prepare and investigate three multidentate diglycolamide ligands for the selective separation of Eu(III) over Am(III) from a nitric acid solution to explore the effect on the extraction of alkyl groups on the nitrogen atoms in the center of the BisDGA ligands. The introduction of ethyl or isopropyl groups on the central nitrogen atoms greatly increased the distribution ratios of trivalent metal ions and enhanced the separation factor of Eu(III) over Am(III). The complexation behaviors of Eu(III) and Am(III) ions were studied by slope analyses, electrospray ionization mass spectrometry (ESI-MS), and extended X-ray absorption fine structure (EXAFS) spectroscopy. The results indicated that the trivalent metal ions were extracted as 1:2 and 1:3 complexes for all three BisDGA ligands during the extraction. Density functional theory (DFT) calculations verified the relevant experimental conclusion that the selectivity of THEE-BisDGA for Eu(III) is better than that for Am(III). The metal-DGA bonds in the ML3(NO3)3 complexes seem to be stronger than those in ML2(NO3)3 complexes.

Effects of simple rain-shelter cultivation on fatty acid and amino acid accumulation in 'Chardonnay' grape berries.

BACKGROUND: Fatty acids and amino acids are the precursors of aliphatic and aromatic volatile compounds, higher alcohols and esters. They are also nutrition for yeast metabolism during fermentation. However, few reports have been concerned about the effect of viticulture practices on the accumulation of fatty acids and amino acids in wine grapes. This study aimed to explore the accumulation of these compounds in developing Vitis vinifera L. cv. Chardonnay grape berries under two vintages, and compare the influences of the rain-shelter cultivation and open-field cultivation. RESULTS: Fifteen fatty acids and 21 amino acids were detected in total. The rain-shelter cultivation led to an increase in the total concentration of fatty acids, and a decrease in the total concentration of amino acids compared with the open-field cultivation in 2012, while no significant difference was observed between two cultivation modes in 2013 vintage. Concentrations of palmitoleic acid, isoleucine and cysteine were significantly promoted in the rain-shelter grape berries, whereas those of tyrosine and ornithine were markedly reduced in both vintages. CONCLUSION: The rain-shelter cultivation of wine grapes in the rainy region is beneficial for improving grape quality and fermentation activity by influence on the concentration of fatty acids and amino acids. © 2017 Society of Chemical Industry.

Lactobacillus paracasei modulates LPS-induced inflammatory cytokine release by monocyte-macrophages via the up-regulation of negative regulators of NF-kappaB signaling in a TLR2-dependent manner.

The application of the probiotic lactobacillus is suggested in the treatment of some inflammatory diseases of intestines due to its potential ability to attenuate inflammation. However, the mechanism is not completely understood. In PBMCs, Lactobacillus paracasei (L. Paracasei) down-regulated the LPS-induced production of TNF-α and IL-6. Using a macrophage-like differentiated THP-1 cell line induced by PMA, we investigated the effect of L. paracasei on the production of pro-inflammatory cytokines by monocyte-macrophages. Treatment of the differentiated THP-1 cells with L. paracasei either concurrently with or before LPS challenge attenuated the LPS-induced secretion of TNF-α and IL-1ß. This effect was due to a decrease in IκB phosphorylation and NF-κB nuclear translocation. Furthermore, treatment of the differentiated THP-1 cells with L. paracasei induced the expression of negative regulators of the NF-κB signaling pathway, including the deubiquitinating enzyme A20, suppressor of cytokine signaling (SOCS) 1, SOCS3, and IL-1 receptor-associated kinase (IRAK) 3. Pretreatment with an IRAK4 inhibitor suppressed the L. paracasei-induced expression of these negative regulators and further increased the LPS-mediated expressions of TNF-α and IL-1ß. Moreover, treatment with an antibody against Toll-like receptor (TLR) 2 reversed the effect of L. paracasei on inducing negative regulators and inhibiting TNF-α and IL-1ß productions. Our findings suggest that L. paracasei inhibits the production of pro-inflammatory cytokines by monocyte-macrophages via the induction of negative regulators of the NF-κB signaling pathway in a TLR2-IRAK4-dependent manner.

Identification of HLA-A*11:01-restricted Mycobacterium tuberculosis CD8(+) T cell epitopes.

New vaccines are needed to combat Mycobacterium tuberculosis (MTB) infections. The currently employed Bacillus Calmette-Guérin vaccine is becoming ineffective, due in part to the emergence of multidrug-resistant tuberculosis (MDR-TB) strains and the reduced immune capacity in cases of HIV coinfection. CD8(+) T cells play an important role in the protective immunity against MTB infections, and the identification of immunogenic CD8(+) T cell epitopes specific for MTB is essential for the design of peptide-based vaccines. To identify CD8(+) T cell epitopes of MTB proteins, we screened a set of 94 MTB antigens for HLA class I A*11:01-binding motifs. HLA-A*11:01 is one of the most prevalent HLA molecules in Southeast Asians, and definition of T cell epitopes it can restrict would provide significant coverage for the Asian population. Peptides that bound with high affinity to purified HLA molecules were subsequently evaluated in functional assays to detect interferon-γ release and CD8(+) T cell proliferation in active pulmonary TB patients. We identified six novel epitopes, each derived from a unique MTB antigen, which were recognized by CD8(+) T cells from active pulmonary TB patients. In addition, a significant level of epitope-specific T cells could be detected ex vivo in peripheral blood mononuclear cells from active TB patients by an HLA-A*11:01 dextramer carrying the peptide Rv3130c194-204 (from the MTB triacylglycerol synthase Tgs1), which was the most frequently recognized epitope in our peptide library. In conclusion, this study identified six dominant CD8(+) T cell epitopes that may be considered potential targets for subunit vaccines or diagnostic strategies against TB.

Methods, Mechanisms, and Application Prospects for Enhancing Extracellular Vesicle Uptake.

Extracellular vesicles (EVs) are considered to be a new generation of bioinspired nanoscale drug delivery systems due to their low immunogenicity, natural functionality, and excellent biocompatibility. However, limitations such as low uptake efficiency, insufficient production, and inhomogeneous performance undermine their potential. To address these issues, numerous researchers have put forward various methods and applications for enhancing EV uptake in recent decades. In this review, we introduce various methods for the cellular uptake of EVs and summarize recent advances on the methods and mechanisms for enhancing EV uptake. In addition, we provide further understanding regarding enhancing EV uptake and put forward prospects and challenges for the development of EV-based therapy in the future.

Mechanism and therapeutic potential of traditional Chinese medicine extracts in sepsis.

Sepsis is a complex syndrome characterized by multi-organ dysfunction, due to the presence of harmful microorganisms in blood which could cause mortality. Complications associated with sepsis involve multiple organ dysfunction. The pathogenesis of sepsis remains intricate, with limited treatment options and high mortality rates. Traditional Chinese medicine (TCM) has consistently demonstrated to have a potential on various disease management. Its complements include reduction of oxidative stress, inhibiting inflammatory pathways, regulating immune responses, and improving microcirculation. Traditional Chinese medicine can mitigate or even treat sepsis in a human system. This review examines progress on the use of TCM extracts for treating sepsis through different pharmacological action and its mechanisms. The potential targets of TCM extracts and active ingredients for the treatment of sepsis and its complications have been elucidated through molecular biology research, network pharmacology prediction, molecular docking analysis, and visualization analysis. Our aim is to provide a theoretical basis and empirical support for utilizing TCM in the treatment of sepsis and its complications while also serving as a reference for future research and development of sepsis drugs.

Single and combined effects of estrone and 17ß-estradiol on male goldfish.

OBJECTIVE: To assess the single and combined effects of estrone (E1) and 17ß-estradiol (E2) on goldfish (Carassius auratus). METHODS: Batch tests were conducted. Serum levels of vitellogenin (VTG) and E2, gonadosomatic indices (GSI), gonadal DNA damage and liver 7-ethoxyresorufin-O-deethylase (EROD) activity were measured after exposure for 14 days. RESULTS: The VTG level increased significantly in a concentration-dependent manner. The serum E2 level was significantly higher and the GSI level was significantly lower in goldfish after exposed to the 3 drugs. DNA damage occurred in treated samples and EROD activity was significantly suppressed 7 days after exposure. The joint effect of E1 and E2 was additive with regard to VTG induction. CONCLUSION: The results of our study highlight a series of effects of steroidal estrogens on goldfish. Further study is needed to confirm their effect as a whole.

Longitudinal association of family conflict and suicidal behaviors among Chinese adolescents: The mediation effect of internalizing and externalizing problems.

OBJECTIVE: Family conflict is a risk factor for suicidal behaviors among adolescents. However, few longitudinal studies have investigated this association and explored the mediation effect of behavioral and emotional problems. This study aimed to examine the longitudinal association between family conflict, internalizing and externalizing problems, and suicidal behaviors in a large sample of Chinese adolescents. METHOD: This longitudinal study of 7,072 adolescents was based on the Shandong Adolescent Behavior & Health Cohort (SABHC). Participants completed a self-administrated questionnaire to assess family conflict, internalizing and externalizing problems, suicidal behaviors, and family demographics at baseline. Excluding adolescents with any suicidal behavior at baseline (N = 839), others (N = 6,233) were allowed to report their internalizing and externalizing problems and suicidal behaviors one-year later. Path analyses were conducted to examine the mediation relationship of internalizing and externalizing problems between family conflict and suicidal behaviors. RESULTS: Of 6,233 participants, mean age was 14.52 at baseline and 51.2% were males. Adolescents with subsequent suicidal behaviors reported higher scores in family conflict, internalizing and externalizing problems (Ps < 0.01). Path analyses showed that internalizing and externalizing problems played a significant mediating role in the associations of family conflict with suicidal behaviors after adjusting for covariates. CONCLUSIONS: Family conflict is associated with suicidal behaviors in adolescents, which is partially mediated by internalizing and externalizing problems. Internalizing problems is the major mediator between family conflict and suicidal thought or suicide plan; however, internalizing and externalizing problems play similar mediating roles in the family conflict-suicide attempt link.

miR-146a-5p Modulates Adult Hippocampal Neurogenesis Deficits Through Klf4/p-Stat3 Signaling in APP/PS1 Mice.

Alzheimer's disease (AD) is the most common neurodegenerative disease, and currently, no effective treatment strategies exist for this condition. MicroRNAs (miRNAs) have emerged as promising therapeutic targets of AD. Previous studies have highlighted the significant role of miR-146a-5p in regulating adult hippocampal neurogenesis (AHN). Here, we aimed to investigate whether miR-146a-5p plays a role in the mechanisms of AD. We employed quantitative real-time PCR (qRT-PCR) to assess the expression of miR-146a-5p. Additionally, we examined the expression of Krüppel-like factor 4 (Klf4), Signal transducer and activator of transcription 3 (Stat3), and phosphorylated Stat3 (p-Stat3) using western blot analysis. Furthermore, we validated the interaction between miR-146a-5p and Klf4 using a dual-luciferase reporter assay. Immunofluorescence staining was employed to evaluate AHN. And Contextual fear conditioning discrimination learning (CFC-DL) experiment was used to detect pattern separation. Our findings in the hippocampus of APP/PS1 mice revealed upregulated levels of miR-146a-5p and p-Stat3, while Klf4 levels were downregulated. Interestingly, both miR-146a-5p antagomir and p-Stat3 inhibitor obviously rescued neurogenesis and pattern separation in APP/PS1 mice. Moreover, application of miR-146a-5p agomir reversed the protective effects of Klf4 upregulation. These findings open new avenues for protection against AD through the modulation of neurogenesis and cognitive decline via the miR-146a-5p/Klf4/p-Stat3 pathway.

Menstrual pain mediated the association between daytime sleepiness and suicidal risk: A prospective study.

BACKGROUND: Adolescents with daytime sleepiness have been demonstrated to have a higher level of suicidal risk than those without. Currently, few studies had examined the pathway from daytime sleepiness to suicidal risk among female adolescents. This study aimed to explore the association among menstrual pain, daytime sleepiness, and suicidal risk among female adolescents in China. METHODS: Of 7072 adolescents who participated in the follow-up survey of Shandong Adolescents Behavior & Health Cohort (SABHC), 3001 were female adolescents who had begun to menstruate and included for the analysis. A structured self-administrated questionnaire was used to measure menstrual pain, daytime sleepiness, suicidal risk and demographic characteristics. Participants were first surveyed in November-December 2015 and resurveyed 1 year later. RESULTS: Of 3001 participants, 11.43 % had suicidal risk, 79.8 % experienced menstrual pain. Cross-lagged analysis showed that there was cause-and-effect relationship between menstrual pain and daytime sleepiness. Moderate (OR = 1.79, 95%CI: 1.22-2.63) and severe (OR = 2.73, 95%CI: 1.80-4.12) menstrual pain (follow-up) were associated with suicidal risk (follow-up). Daytime sleepiness (baseline: OR = 1.04, 95%CI: 1.02-1.06, follow-up: OR = 1.07, 95%CI: 1.05-1.09) had effects on suicidal risk (follow-up). Mediation analysis showed that menstrual pain played a partially mediating role between daytime sleepiness and suicidal risk, with the indirect effect being 0.002 (95%CI: 0.001-0.004). LIMITATIONS: All data were self-reported. CONCLUSIONS: Menstrual pain and daytime sleepiness had effects on each other, and they both were the risk factors of suicidal risk. Among female adolescents, the association between daytime sleepiness and suicidal risk could be partially mediated by menstrual pain. Releasing the menstrual pain of female adolescents with daytime sleepiness could reduce their suicidal risk.

Case Report: Chronic inflammatory demyelinating polyradiculoneuropathy rather than hemophagocytic lymphohistiocytosis-the initial phenotype of PRF1 gene mutation.

Perforin is essentially involved in the granule-dependent killing activities of cytotoxic T lymphocytes and NK cells. Monoallelic PRF1 mutation increases the risk of autoimmune diseases, and biallelic PRF1 mutation causes familial hemophagocytic lymphohistiocytosis-2. Here, we report a case of a 12-year-old girl with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), followed by a rapidly progressive onset of hemophagocytic lymphohistiocytosis (HLH) 9 months later, alongside manifestations of demyelinating encephalopathy. Genetic sequencing revealed a heterozygous nonsense mutation in the PRF1 gene (c.984G>A; p.W328*) and a heterozygous missense mutation in the PRF1 gene (c.1349C>T; p.T450M). Eventually, she died because of no suitable allogeneic hematopoietic stem cell available in time. Our observations suggest that CIPD might represent the initial phenotype of biallelic PRF1 mutation and could serve as an early sign of subsequent HLH. A comprehensive understanding of this condition is paramount for timely diagnosis, treatment, and ultimately improved patient outcomes.

The circ_0002538/miR-138-5p/plasmolipin axis regulates Schwann cell migration and myelination in diabetic peripheral neuropathy.

Circular RNAs (circRNAs) play a vital role in diabetic peripheral neuropathy. However, their expression and function in Schwann cells in individuals with diabetic peripheral neuropathy remain poorly understood. Here, we performed protein profiling and circRNA sequencing of sural nerves in patients with diabetic peripheral neuropathy and controls. Protein profiling revealed 265 differentially expressed proteins in the diabetic peripheral neuropathy group. Gene Ontology indicated that differentially expressed proteins were mainly enriched in myelination and mitochondrial oxidative phosphorylation. A real-time polymerase chain reaction assay performed to validate the circRNA sequencing results yielded 11 differentially expressed circRNAs. circ_0002538 was markedly downregulated in patients with diabetic peripheral neuropathy. Further in vitro experiments showed that overexpression of circ_0002538 promoted the migration of Schwann cells by upregulating plasmolipin (PLLP) expression. Moreover, overexpression of circ_0002538 in the sciatic nerve in a streptozotocin-induced mouse model of diabetic peripheral neuropathy alleviated demyelination and improved sciatic nerve function. The results of a mechanistic experiment showed that circ_0002538 promotes PLLP expression by sponging miR-138-5p, while a lack of circ_0002538 led to a PLLP deficiency that further suppressed Schwann cell migration. These findings suggest that the circ_0002538/miR-138-5p/PLLP axis can promote the migration of Schwann cells in diabetic peripheral neuropathy patients, improving myelin sheath structure and nerve function. Thus, this axis is a potential target for therapeutic treatment of diabetic peripheral neuropathy.

Nightmare distress as a mediator between frequent nightmares and depressive symptoms in Chinese adolescents.

BACKGROUND: Frequent nightmares are related to depressive symptoms in adolescents. Little is known about pathways from frequent nightmares to depressive symptoms. This study aimed to examine the mediation effect of nightmare distress in the association between frequent nightmares and depressive symptoms in a large sample of Chinese adolescents. METHODS: A total of 11,831 adolescents who participated in the baseline survey of Shandong Adolescent Behavior and Health Cohort were included in the analysis. A self-administered questionnaire was used to measure nightmare frequency, nightmare distress, depressive symptoms, sleep duration, insomnia, and demographic characteristics. Linear regressions and mediation analyses were performed to examine the associations between frequent nightmares, nightmare distress and depressive symptoms. RESULTS: Of 11,831 participates, 50.9% were males and the mean age was 14.97 ± 1.45. Adolescents with frequent nightmares scored significantly higher on nightmare distress (t = 29.87, P <  0.001) and depressive symptoms (t = 20.05, P < 0.001) than those adolescents without frequent nightmares. Frequent nightmares (ß = 1.04, 95% CI: 0.48-1.60) and nightmare distress (ß = 0.30, 95% CI: 0.28-0.32) were associated with depressive symptoms. Mediation analyses showed that nightmare distress accounted for 63.76% of the total effects in the entire sample, 51.17% in males and 80.00% in females, respectively. LIMITATION: No causality could be made from the cross-sectional data and possible information bias due to self-report. CONCLUSIONS: The association between frequent nightmares and depressive symptoms appears to be substantially mediated by nightmare distress. Assessing and intervening distress associated with frequent nightmares may have important clinical implications for reducing the risk of depression in adolescents.

Depressive symptoms as a mediator between perceived social support and suicidal ideation among Chinese adolescents.

OBJECTIVE: Little is known about the association between perceived social support (PSS) and suicidal ideation in Chinese adolescents. This study was to examine the association of perceived social support and suicidal ideation (SI) and the mediating role of depressive symptoms in a large sample of adolescents in China. METHOD: A total of 11,831 adolescents who participated in the baseline Shandong Adolescent Behavior & Health Cohort were included for analysis. Perceived social support, depressive symptoms, and other variables were assessed by a self-administrated questionnaire. Path analysis was used to estimate the association between PSS, depressive symptoms, and suicidal ideation. RESULTS: The prevalence rate of SI in the past year was 12.5%. Suicidal ideation and depressive symptoms were significantly associated with low PSS from family, friends, and significant others. Path analysis revealed that depressive symptoms partially mediated the relationship between PSS from family, friends, and significant others and suicidal ideation. After controlling for covariates, the mediation effect proportion of depressive symptoms on the associations between perceived social support from family, friends, and significant others and SI ranged from 19.20% to 62.12%. LIMITATIONS: As this is a cross-sectional study, no causal relationship could be made. CONCLUSIONS: Depressive symptoms partially mediated the association between perceived social support and suicidal ideation. Longitudinal research is needed to better understand the association between social support and suicidal ideation in adolescents.

Longitudinal associations of the duration of mobile phone use with suicidal behavior in adolescents: The mediating role of depressive symptoms.

BACKGROUND: Prolonged mobile phone use has been demonstrated to be associated with mental health problems and suicidal behavior in adolescents. This study examined the mediating role of depressive symptoms in the association between duration of mobile phone use (DMPU) and suicidal behavior in adolescents. METHODS: A total of 6,923 participants from the Shandong Adolescent Behavior & Health Cohort (SABHC) were included in the analysis. Participants completed a self-administered questionnaire to assess DMPU on weekdays and weekends, mental disorders, insomnia symptoms, depressive symptoms, suicidal behavior (thought, plan, or attempt), and family demographics in November-December 2015. One year later, a follow-up survey was conducted to ask participants to report their depressive symptoms and suicidal behavior. Path analyses with logistic regressions were performed to examine the mediating role of depressive symptoms in the DMPU-suicidal behavior link. RESULTS: Of the sample, mean age was 14.58 (SD = 1.45) and 3,455 (49.9 %) were female at baseline. 12.12 % of participants reported having ever suicidal behavior during the past 12 months at baseline, and 10.63 % reported having ever suicidal behavior during 1-year follow-up. Path analyses showed that the depressive symptoms played a partial mediating role in the association of DMPU on weekdays and weekends with subsequent suicidal behavior. After controlling for covariates, depressive symptoms accounted for 33.6 % and 58.6 % of the total effect of DMPU on weekdays and weekends on suicidal behavior, respectively. LIMITATION: All variables were measured based on self-report. CONCLUSIONS: The link between DMPU and suicidal behavior was partially mediated by depressive symptoms. Prolonged mobile phone use and depressive symptoms should be assessed and intervened to prevent suicidal behavior in adolescents.