A network analysis of depressive symptoms, psychosocial factors, and suicidal ideation in 8686 adolescents aged 12-20 years.

Suicide has aroused global concern, and a better understanding of the complex interactions between suicide ideation and various psychopathological features is critical. We aimed to explore the complex interplays among adolescents. This study adopted a multistage stratified cluster sampling method and recruited adolescents aged 12 to 20 year-old from 8 middle and high schools between December 2020 and September 2021 in Guangzhou, China. We assessed loneliness, social support, bullying victimization, depressive symptoms, and suicidal ideation. We used network analysis to examine the network structure of the correlates of suicidal ideation and identify central symptoms and bridge symptoms. We used case-drop bootstrapping and correlation stability coefficients to examine the stability of the network. Among 8686 adolescents, 347 (4 %) adolescents reported suicidal ideation in the past two weeks. Network analyses identified 'hopeless', 'psychomotor', and 'failure' were the three strongest edges linked to suicidal ideation. The most central nodes were identified as 'hopeless' being the most central node, followed by loneliness and verbal bullying victimization, while sexual bullying victimization, sex, and relational bullying were the strongest bridging symptoms. The findings shed light on the complexity of associations of suicidal ideation and could provide insight into school-based suicide risk assessment and prevention for adolescents.

Glutamate levels in the ventromedial prefrontal cortex and resting-state functional connectivity within reward circuits in alcohol-dependent patients.

Great progress has been made in understanding the neural mechanisms associated with alcohol-dependent (AD) patients. However, the interactions within the reward circuits of the patients need further exploration. Glutamatergic projections from the prefrontal cortex to some brain regions are present in the reward circuit. However, little is known about the potential implications of glutamate levels in the prefrontal cortex on abnormal interactions within reward circuits in AD patients. To determine the potential roles of reward circuits in drinking, we investigated differences in resting-state functional connectivity (RSFC) and multivariate Granger causality analysis between 20 AD patients and 20 healthy controls (HC). The neuroimaging findings were then correlated with clinical variables (alcohol use disorder identification test). The ventromedial prefrontal cortex (VmPFC) is believed to play a critical role in addiction disorders, and glutamatergic projections from the prefrontal cortex to several regions of the brain are present in reward circuits. Proton magnetic resonance spectroscopy was also performed to assess the difference in glutamate levels in VmPFC between AD patients and HC. The results showed that the strength of functional connectivity in the reward circuit was generally attenuated in AD patients, and the reciprocal enhancement of activity between the right insula, left thalamus and VmPFC was found to be significantly greater in AD patients. It is worth noting that although glutamate levels in the VmPFC did not show significant differences between the two groups, the level of glutamate in the VmPFC was significantly correlated with RSFC. We hope that the current findings will help us to develop new intervention models based on the important role of the VmPFC in AD.

Right arcuate fasciculus and left uncinate fasciculus abnormalities in young smoker.

Previous diffusion tensor imaging (DTI) studies had investigated the white matter (WM) integrity abnormalities in smokers. Exposure to nicotine disrupts neurodevelopment during adolescence, possibly by disrupting the trophic effects of acetylcholine. However, little is known about the diffusion parameters of specific fibre bundles at multiple locations in young smokers. Thirty-seven young smokers and 29 age-, education- and gender-matched healthy non-smokers participated in this study. Automated Fibre Quantification (AFQ) was employed to investigate the WM microstructure in young smokers by integrating multiple indices. Diffusion parameters, that is, fractional anisotropy (FA), axial diffusion (AD), radial diffusion (RD) and mean diffusion (MD), were calculated at 100 points along the length of 18 major brain tracts. The relationships between neuroimaging differences and smoking behaviours were explored, including Fagerström Test of Nicotine Dependence (FTND) and pack-years. Compared with non-smokers, young smokers showed significantly increased FA, AD and decreased RD in the left uncinate fasciculus (UF) and right thalamic radiation (TR), increased AD, RD and decreased FA in the right arcuate fasciculus (Arc). Correlation analyses revealed that FA values of the left UF and RD values of the right Arc were negatively correlated with FTND score in smokers and FA values of the right Arc were positively correlated with FTND scores. Positive correlation was observed between AD values of the left UF and pack-years in smokers. The findings enhanced our understanding of the potential effect of adolescent smoking on WM microstructure.

Abnormal functional connectivity of the salience network in insomnia.

The salience network plays an important role in detecting stimuli related to behavior and integrating neural processes. The aim of this study was to investigate changes in functional connectivity of the salience network in insomnia patients. Independent component analysis combined with a dual regression approach was used to examine functional connectivity differences in the salience network between patients with insomnia (n = 33) and healthy controls (n = 33). Pearson correlation analysis was used to analyze the relationship between differences in functional connectivity and the clinical characteristics of insomnia patients. Compared to healthy controls, insomnia patients showed increased functional connectivity in the dorsal anterior cingulate cortex within the salience network, as well as greater connectivity between the salience network and other brain regions including the dorsolateral prefrontal cortex, superior frontal gyrus, sensorimotor area and brain stem. The correlation analysis showed that increased functional connectivity between the salience network and left dorsolateral prefrontal cortex was positively correlated with Pittsburgh Sleep Quality Index score. Increased functional connectivity between salience network and several brain regions may be related to hyperarousal in insomnia patients. The connectivity between salience network and dorsolateral prefrontal cortex may potentially be used as a neuroimaging biomarker of sleep quality.

Dynamic Neuroimaging Biomarkers of Smoking in Young Smokers.

OBJECTIVE: To examine potential changes in the dynamic characteristics of regional neural activity in young smokers and to detect whether the changes were associated with smoking behavior. METHODS: The dynamic regional homogeneity (dReHo) and dynamic amplitude of low-frequency fluctuations (dALFF) in 40 young smokers and 42 nonsmokers were compared. Correlation analyses were also performed between dReHo and dALFF in areas showing group differences and smoking behavior [e.g., the Fagerström Test for Nicotine dependence (FTND) scores and pack-years]. RESULTS: Significantly differences in dReHo variability were observed in the inferior frontal gyrus (IFG), superior frontal gyrus (SFG), medial frontal gyrus (MFG), insula, cuneus, postcentral gyrus, inferior semi-lunar lobule, orbitofrontal gyrus, and inferior temporal gyrus (ITG). Young smokers also showed significantly increased dALFF variability in the anterior cingulate cortex (ACC) and ITG. Furthermore, a significant positive correlation was found between dALFF variability in the ACC and the pack-years; whereas a significant negative correlation between dReHo variability in the IFG and the FTND scores was found in young smokers. CONCLUSION: The pattern of resting state regional neural activity variability was different between young smokers and nonsmokers. Dynamic regional indexes might be a novel neuroimaging biomarker of smoking behavior in young smokers.

Negative life events and major depressive disorder among HIV-positive individuals in Guangdong, China: A cross-sectional study.

HIV-positive individuals encounter a number of negative life events (NLEs). This cross-sectional study aimed to evaluate the association between NLEs and major depressive disorder (MDD) among HIV-positive individuals in Guangdong, China, about which little is known.HIV-positive individuals were recruited from the Centers for Disease Prevention and Control of Guangzhou, Zhongshan, and Yangjiang from September 2007 to September 2008. Data on NLEs were collected using a questionnaire. The Structured Clinical Interview for DSM-IV-TR Axis I Disorders-Patient Edition (SCID-I/P) based on the DSM-IV criteria was used to diagnose MDD. Multiple logistic regression analyses were conducted to evaluate the association between NLEs and MDD.Among the 339 participants, 306 (90.27%) reported that one or more NLEs had ever occurred. Participants who reported NLEs that included HIV infection, financial problems, AIDS diagnosis, HIV/AIDS discrimination, conflict with spouse or lover, conflict with other family members, problems in childbearing, and conflict with nonfamily were at a higher risk of MDD. Participants who reported more NLEs in the last year had a higher risk of MDD (OR = 2.86, 95%CI: 1.76-4.65) than individuals who reported fewer NLEs. Individuals with higher chronic stress scores had a higher risk of MDD (OR = 4.36, 95%CI: 2.44-7.78) than individuals with lower chronic stress scores. However, acute stress was not associated with MDD.NLEs were common among HIV-positive individuals. MDD was associated with a greater number of NLEs and the increased chronic stress caused by the NLEs. Interventions should be tailored to those who reported NLEs to help reduce the risk of MDD and increase the quality of life among HIV-positive individuals.

Carbene-Catalyzed α-Carbon Amination of Chloroaldehydes for Enantioselective Access to Dihydroquinoxaline Derivatives.

An NHC-catalyzed α-carbon amination of chloroaldehydes was developed. Cyclohexadiene-1,2-diimines are used as amination reagents and four-atom synthons. Our reaction affords optically enriched dihydroquinoxalines that are core structures in natural products and synthetic bioactive molecules.

Prevalence of and factors associated with major depressive disorder among HIV-positive individuals in Guangdong, China.

BACKGROUND: People living with HIV may suffer from mental disorders. We aimed to explore the prevalence of and factors associated with major depressive disorder (MDD) among HIV-positive individuals in Guangdong, China, about which little is known. METHODS: A cross-sectional study was conducted to recruit HIV-positive individuals from the Centers for Disease Prevention and Control of Guangzhou, Zhongshan, and Yangjiang from September 2007 to September 2008. Data were collected by questionnaires. MDD was diagnosed and assessed by two psychiatrists using the Structured Clinical Interview for DSM-IV-TR Axis I Disorders-Patient Edition (SCID-I/P) based on the DSM-IV criteria. Multiple logistic regression analyses were conducted to explore the factors associated with MDD. RESULTS: The prevalences of lifetime MDD and current MDD among the 339 included participants were 22.71% (95% confidence interval [CI]: 18.25-27.17%) and 12.09% (95%CI: 8.62%-15.57%), respectively. The results of multiple logistic regression showed that patients with AIDS had a higher risk of lifetime MDD (odds ratio [OR] = 2.69, 95%CI: 1.38-5.26) and current MDD (OR = 3.51, 95%CI: 1.59-7.75) than HIV-infected individuals. Participants with more number of negative life events were more likely to have lifetime MDD (OR = 2.33, 95%CI: 1.34-4.06) and current MDD (OR = 3.77, 95%CI: 1.76-8.09) than individuals with fewer negative life events. Individuals with higher score of social support were less likely to have lifetime MDD (OR = 0.45, 95%CI: 0.26-0.80) and current MDD (OR = 0.46, 95%CI: 0.21-0.97) than individuals with less social support. CONCLUSIONS: The prevalence of MDD was high among HIV-positive individuals in China. AIDS diagnosis, decreased social support, and an increased number of negative life events were risk factors for MDD.

Kinetic Resolution of 1,2-Diols via NHC-Catalyzed Site-Selective Esterification.

A kinetic resolution of 1,2-diols bearing both a secondary and a primary alcohol motif through an N-heterocyclic carbene-catalyzed oxidative acylation reaction has been developed. A site- and enantioselective esterification reaction is involved for this process. Both the monoacylated diols obtained and the remaining enantioenriched 1,2-diols are versatile building blocks for the preparation of functional molecules with proven biological activities.

Prevalence of mild cognitive impairment and its subtypes in community-dwelling residents aged 65 years or older in Guangzhou, China.

BACKGROUND: Prevalence of mild cognitive impairment (MCI) has been reported substantial variations, and mostly in Western countries. Less is known about MCI in the south of China. The study is to estimate the prevalence of MCI and its subtypes in residents aged 65year or older in community-dwelling residents of Guangzhou, China. METHODS: The study was a community-based, cross-sectional study conducted in rural and urban areas of Guangzhou between April and October 2009. Eight communities were randomly selected using a cluster sampling method. Each elderly was interviewed with Montreal Cognitive Assessment, the Mini-Mental state examination, Auditory Verbal Learning Test, the Clinical Dementia Rating scale et al. MCI was classified as amnestic MCI (a-MCI) or nonamnestic MCI (na-MCI). RESULTS: 2427 individuals were contacted, but in-person interviews were conducted with 2111 participants. 299 participants with MCI were identified. The prevalence of MCI, a-MCI and na-MCI was 14.2%, 12.2%, 2.0% respectively. The prevalence of MCI and a-MCI increased with age, decreased with education level, and was higher in rural areas than in urban areas. The difference of prevalence of MCI and a-MCI between women with men wasn't statistically significant(MCIχ2=1.0, OR 0.9, 95%CI=0.6-1.2; a-MCIχ2=1.0, OR 0.9, 95%CI=0.6-1.2), when controlling for education by logistic regression analysis. CONCLUSIONS: The results suggest that 14.2% of elderly individuals are affected by MCI in Guangzhou, China. And MCI was dominated by a-MCI. The prevalence of MCI and a-MCI increased with age, decreased with education level, and was higher in the rural population compared to the urban population.

Direct Activation of ß-sp3-Carbons of Saturated Carboxylic Esters as Electrophilic Carbons via Oxidative Carbene Catalysis.

An N-heterocyclic carbene-catalyzed oxidative LUMO activation of the ß-cabons of saturated carboxylic esters is disclosed. This approach allows for efficient asymmetric access to lactams and lactones by directly installing functional groups to the typically inert ß-sp3 carbons of saturated esters. The use of HOBt as an additive was found to significantly improve both yields and enantioselectivities of the reactions.