Highly efficient waveguide-coupled output in asymmetrically deformed square cavity microlasers.

We propose and demonstrate deformed square cavity microlasers for realizing highly efficient output from a connected waveguide. The square cavities are deformed asymmetrically by replacing two adjacent flat sides with circular arcs to manipulate the ray dynamics and couple the light to the connected waveguide. The numerical simulations show that the resonant light can efficiently couple to the fundamental mode of the multi-mode waveguide by carefully designing the deformation parameter utilizing global chaos ray dynamics and internal mode coupling. An enhancement of approximately six times in the output power is realized in the experiment compared to the non-deformed square cavity microlasers, while the lasing thresholds are reduced by about 20%. The measured far-field pattern shows highly unidirectional emission agreeing well with the simulation, which confirms the feasibility of the deformed square cavity microlasers for practical applications.

Wideband multiwavelength Brillouin fiber laser with switchable channel spacing.

A multiwavelength Brillouin fiber laser (MBFL) with a switchable channel spacing is demonstrated using a 1.55-µm single-mode AlGaInAs/InP hybrid square-rectangular laser as a seeding source. The scheme employs a highly nonlinear fiber loop with a feedback path to generate a 10-GHz-spacing MBFL. Then, assisted by a tunable optical bandpass filter, MBFLs with spacing from 20 GHz to 100 GHz at a step of 10 GHz are generated in another highly nonlinear fiber loop based on the cavity-enhanced four-wave mixing. More than 60 lasing lines with an optical signal-to-noise ratio over 10 dB are obtained successfully in all the switchable spacings. The total output power and the channel spacing of the MBFLs are proved to be stable.

Profiles and characteristics of clinical subtypes of perinatal depressive symptoms: A latent class analysis.

AIMS: To investigate clinically relevant subtypes of perinatal depressive symptoms. DESIGN: Cross-sectional study. METHODS: A sample of 2,783 women at different prenatal and postnatal periods was recruited between August 2015 - August 2017. The Patient Health Questionnaire-9 (PHQ-9) was used to assess depressive symptoms. Data analyses consisted of latent class analysis (LCA), analysis of variance and multinomial logistic regression. RESULTS: (a) Five latent subtypes (Classes 5/4/3/1/2) were identified: 'no symptoms', 'mild physio-somatic symptoms', 'severe physio-somatic symptoms and moderate anhedonia', 'moderate-to-severe symptoms' and 'severe symptoms'; (b) Postpartum women were more likely to belong to the severe depressive symptoms group, whereas pregnant women were likely to report severe physio-somatic symptoms; and (c) History of abortion and perinatal complications increased the likelihood of belonging to all moderate-to-severe classes. Lower levels of education increased the probability of belonging to Class 2. Younger women were more likely to be categorized into Classes 1 and 2. CONCLUSIONS: This is the first study to examine heterogeneity of perinatal depressive symptoms and delineate the characteristics of subtypes at different prenatal and postnatal periods via the PHQ-9, using LCA in a Chinese general population. IMPACT: This research details the heterogeneity of perinatal depressive symptoms and delineates the characteristics of subtypes at different prenatal and postnatal periods in a Chinese general population.

Predictors of occupational burnout among nurses: a dominance analysis of job stressors.

AIMS AND OBJECTIVES: To quantitatively compare dimensions of job stressors' effects on nurses' burnout. BACKGROUND: Nurses, a key group of health service providers, often experience stressors at work. Extensive research has examined the relationship between job stressors and burnout; however, less has specifically compared the effects of job stressor domains on nurses' burnout. DESIGN: A quantitative cross-sectional survey examined three general hospitals in Jinan, China. METHOD: Participants were 602 nurses. We compared five potential stressors' ability to predict nurses' burnout using dominance analysis and assuming that each stressor was intercorrelated. RESULTS: Strong positive correlations were found between all five job stressors and burnout. Interpersonal relationships and management issues most strongly predicted participants' burnout (11·3% of average variance). CONCLUSION: Job stressors, and particularly interpersonal relationships and management issues, significantly predict nurses' job burnout. RELEVANCE TO CLINICAL PRACTICE: Understanding the relative effect of job stressors may help identify fruitful areas for intervention and improve nurse recruitment and retention.

Perinatal depression: Data-driven subtypes derived from life history and mindfulness and personality.

BACKGROUND: Perinatal depression is the most prevalent mental disorder during the perinatal period, and research suggests that it presents heterogeneously. We aimed to explore how subtypes of perinatal depression present in terms of multivariate patterns of stable characteristics. METHODS: A cohort study was conducted from March 2016 to March 2018 with Chinese women in the prenatal period (n = 3186). Of the participants, 682 (21.41%) women with Edinburgh Postnatal Depression Scale scores ≥10, indicating probable depression, were included, with the remaining 2504 (78.59%) representing the control group. We assessed mood distress, cognition, life history, emotional regulation, and personality, and used latent class analysis and latent transition analysis to identify perinatal depression subtypes. Of the 682 women with probable depression, only 598 were included in the full analyses, as they completed at least 10 questionnaires. A second, non-overlapping sample and a follow-up cohort were used. RESULTS: We identified four subtypes: 1) a highly distressed type characterized by distress across all domains, high levels of rumination and neuroticism, and reduced trait mindfulness; 2) two moderately distressed types: one with high trauma and low perceived social support, and another with low trauma, high perceived social support, and expressive suppression; and 3) a slightly distressed subtype. LIMITATIONS: We only collected cost and time spent in hospital from medical records. We only had a small follow-up sample. CONCLUSIONS: This multidimensional subtyping of women with perinatal depression could help reduce the apparent heterogeneity of perinatal depression. Distinguishing the subtype characteristics facilitates identifying underlying causes of perinatal depression.

Effect of the interaction between oxytocin receptor gene polymorphism (rs53576) and stressful life events on aggression in Chinese Han adolescents.

OBJECTIVES: Accumulating evidence suggests that stressful life events are associated with increased risk for aggressive behavior in adolescents; however, aggressive reactions to life stressors exhibit large individual differences. The present study sought to examine whether the interaction between a single nucleotide polymorphism (SNP [rs53576]) within the oxytocin receptor gene (OXTR) and stressful life events is related to aggression in Chinese Han adolescents. METHODS: A total of 197 Chinese Han adolescents (14-17 years of age) were included in this study. Aggression was assessed using the 12-item short version of Buss and Perry Aggression Questionnaire. Stressful life events during the past 12 months were assessed using the Adolescent Self-Rating Life Events Checklist. Genomic DNA was extracted from saliva and buccal cells from each individual. RESULTS: Multivariate analysis of variance yielded a significant interaction between OXTR rs53576 SNP and life stress (F = 2.449, p = 0.043, partial η2 = 0.051) and of sex × SNP × life stress (F = 3.144, p = 0.016, partial η2 = 0.064). High life stress during the past 12 months was associated with high levels of physical aggression and hostility in OXTR rs53576 homozygous AA adolescents but not in G-carrier adolescents. In boys, homozygous AA individuals in the high life stress group reported significantly higher levels of physical aggression than participants in the other three groups; the interaction, however, was not significant in girls. CONCLUSIONS: This study, which analyzed a specific gene-environment interaction, demonstrated that AA OXTR rs53576 homozygosity may correlate with higher levels of aggression under high life stress conditions with a sample of healthy Chinese Han adolescents. These findings promote the etiological understanding of adolescent aggression, highlighting the complex effect of stressful life events on aggression, and adding evidence supporting the relationship between the oxytocin system and aggressive behavior in adolescents.

Association between child maltreatment and prospective and retrospective memory in adolescents: The mediatory effect of neuroticism.

The purpose of this study was to examine the relationship between child maltreatment and prospective and retrospective memory in children/adolescents by investigating the mediating role of neuroticism. In total, 662 children/adolescents aged 10-16 years were recruited from a middle school in China, and they completed questionnaires comprising the Childhood Trauma Questionnaire, Prospective and Retrospective Memory Questionnaire, and the Neuroticism subscale of the NEO Five-Factor Inventory. The severity of maltreatment was positively associated with the severity of impairment of memory (prospective and retrospective considered together) in children/adolescents. Children/adolescents exposed to maltreatment tended to display higher levels of neuroticism. Neuroticism partially mediated the association between child maltreatment and memory in all the subjects. The results of multigroup analyses showed neuroticism fully mediated the relationship between child maltreatment and memory for boys, in which the effect size of indirect effect was 0.52, and partially mediated the association for girls with 0.44 effect size of indirect effect. Early intervention aimed to reduce neuroticism might contribute to a better prognosis in children/adolescences with poor memory function.