Time Spent on Private Tutoring and Sleep Patterns of Chinese Adolescents: Evidence from a National Panel Survey.

OBJECTIVE: In recent decades, there has been a marked increase in private tutoring and a decline in sleep health among adolescents. This study aimed to outline the association between time spent on private tutoring and sleep patterns of Chinese adolescents. METHODS: Participants were from a nationwide two-wave panel survey. We performed OLS regressions of sleep duration at wave 2 and Poisson regressions of sleep problems at wave 2 on tutoring time at wave 2, adjusting for baseline sleep duration and other covariates. Tutoring time was assessed by three items: daily hours of tutoring, daily hours of tutoring on weekdays, and daily hours of tutoring on weekends. RESULTS: Overall, more time spent on private tutoring was associated with shorter sleep duration and more sleep problems. Furthermore, both weekday and weekend tutoring can have a positive effect on the number of sleep problems. With regard to sleep duration, weekend tutoring time played a negative role, while the effect of weekday tutoring time was negligible. CONCLUSION: In the Chinese context, which is characterized by intense academic competition, participation in private tutoring plays a significant role in shaping students' sleep duration and sleep problems. To improve the sleep health of adolescents, the time spent on private tutoring should be carefully monitored and regulated.

Indebtedness and mental health in China: the moderating roles of income and social support.

Objective: To explore the effect of indebtedness on mental health and the moderating effects of two types of coping resources (i.e., income and social support) in the Chinese context. Methods: 41,274 adults from four waves of China Family Panel Studies conducted in 2012, 2016, 2018, and 2020. Center for Epidemiologic Studies Depression Scale was used for investigation. Pooled ordinary least squares regressions were used to examine the effect of indebtedness on mental health and the moderating effects of income and social support. Stata 16.0 was used to conduct data analysis. Results: The results showed that indebtedness had an adverse effect on mental health among Chinese adults. Furthermore, debtors with higher incomes showed fewer mental disorders than those with lower incomes. In terms of social support, monetary support from relatives was able to moderate the negative effects of indebtedness; however, the moderating effects of emotional support were negligible. Conclusion: The results of this study indicated the adverse mental health outcomes of indebtedness in emerging economies and highlighted that economic resources played protective roles against debtors' mental disorders.

Families, Schools, and the Longitudinal Changes in Psychological Distress among College Students during the First Year of the COVID-19 Pandemic: Evidence from a National Panel Survey in China.

BACKGROUND: The psychological well-being of students in higher education has become an increasingly important concern in the context of the COVID-19 pandemic. The majority of prior studies were cross-sectional and thereby failed to capture the individual changes in mental health over time. Moreover, few studies have explored whether and how socioeconomic and education backgrounds could be related to college students' mental health changes. This study aimed to fill these gaps. METHODS: Data were from a nationwide, two-wave panel survey of college students in China. Baseline information was collected in November 2019, i.e., before the outbreak of the COVID-19 epidemic in China. A follow-up survey was conducted in November and December 2020, when the epidemic was effectively contained in mainland China. In both waves, mental health was assessed with the 10-item Kessler Psychological Distress Scale (K10). The between-wave changes in psychological distress were measured and categorized. RESULTS: Overall, 13.5% of students experienced at least a one-standard-deviation increase in psychological distress over the one-year follow-up. Results from both bivariate and multivariable analysis showed that this marked distress increase was more pronounced among vocational college students (vs. academic undergraduate and postgraduate students) and those with lower levels of academic performance. In contrast, family socioeconomic status (as measured by parental education, family economic condition, and current residence) was not associated with distress changes over time. CONCLUSIONS: These findings highlight the importance of the educational disparities within the higher education system in understanding the mental health dynamics of college students in the context of the COVID-19 pandemic.

Epithelial-mesenchymal plasticity determines estrogen receptor positive breast cancer dormancy and epithelial reconversion drives recurrence.

More than 70% of human breast cancers (BCs) are estrogen receptor α-positive (ER+). A clinical challenge of ER+ BC is that they can recur decades after initial treatments. Mechanisms governing latent disease remain elusive due to lack of adequate in vivo models. We compare intraductal xenografts of ER+ and triple-negative (TN) BC cells and demonstrate that disseminated TNBC cells proliferate similarly as TNBC cells at the primary site whereas disseminated ER+ BC cells proliferate slower, they decrease CDH1 and increase ZEB1,2 expressions, and exhibit characteristics of epithelial-mesenchymal plasticity (EMP) and dormancy. Forced E-cadherin expression overcomes ER+ BC dormancy. Cytokine signalings are enriched in more active versus inactive disseminated tumour cells, suggesting microenvironmental triggers for awakening. We conclude that intraductal xenografts model ER + BC dormancy and reveal that EMP is essential for the generation of a dormant cell state and that targeting exit from EMP has therapeutic potential.

High-Performance Electrostrictive Relaxors with Dispersive Endotaxial Nanoprecipitations.

Ultrahigh-precision manufacturing and detection have highlighted the importance of investigating electrostrictive materials with a weak stimulated extrinsic electric field and a simultaneous large hysteresis-free strain. In this study, a new type of electrostrictive relaxor ferroelectric is designed by constructing a complex inhomogeneous local structure to realize excellent electrostrictive properties. A remarkably large electrostrictive coefficient, M33 (8 × 10-16 m2 V-2 ) is achieved. Through a combined atomic-scale scanning transmission electron microscopy and advanced in situ high-energy synchrotron X-ray diffraction analysis, it is observed that such superior electrostrictive properties can be ascribed to a special domain structure that consists of endotaxial nanoprecipitations embedded in a polar matrix at the phase boundary of the rhombohedral/tetragonal/cubic phases. The matrix contributes to the high strain response under the weak extrinsic electric field because of the highly flexible polarization and randomly dispersed endotaxial nanoprecipitations with a nonpolar central region, which provide a strong restoring force that reduces the strain hysteresis. The approach developed in this study is widely applicable to numerous relaxor ferroelectrics, as well as other dielectrics, for further enhancing their electrical properties, such as electrostriction and energy-storage capacity.

High Piezoelectric Performance in Pb(Ni1/3Nb2/3)O3-Pb(Sc1/2Nb1/2)O3-PbTiO3 Ternary System Featuring Small Structural Distortion and Heterogeneous Domain Configuration.

Ternary/polynary perovskite solid solutions based on binary systems are well-known for their high piezoelectric performance. In this work, a series of Pb(Ni1/3Nb2/3)O3-Pb(Sc1/2Nb1/2)O3-PbTiO3 compositions with the particularly high piezoelectric coefficient of d33* > 1000 pm/V and d33 > 700 pC/N have been developed. The optimal performance was achieved in the 0.52PNN-0.14PSN-0.34PT composition (d33* = 1120 pm/V, d33 = 804 pC/N, and Tm = 109 °C). The high piezoelectric performance of this system is reported and is superior to those of most lead-based ternary/polynary ceramics. By a combination of in situ high-energy synchrotron diffraction with transmission electron microscopy (TEM), the origin of the high piezoelectric response has been unambiguously revealed. Upon application of an external electric field, synchrotron diffraction profiles show no splitting but prominent shifting, indicating that the large intrinsic lattice strain arising from the reduced crystal anisotropy and facilitated polarization variation is associated with the high piezoelectric response. Furthermore, microscopic studies by TEM highlight a heterogeneous ferroelectric domain configuration generated by a small local structural distortion, which is also beneficial for the high piezoelectric performance in the proposed ternary piezoelectric systems. The design process of ternary perovskite solid solutions with a wide morphotropic phase boundary region and small structural distortion may be enlightening for the exploration of other high-performance polynary piezoelectrics.

SMRT sequencing of the full-length transcriptome of Gekko gecko.

Tokay Gecko (Gekko gecko) is a rare and endangered medicinal animal in China. Its dry body has been used as an anti-asthmatic agent for two thousand years. To date, the genome and transcriptome of this species remain poorly understood. Here, we adopted single molecule real-time (SMRT) sequencing to obtain full-length transcriptome data and characterized the transcriptome structure. We identified 882,273 circular consensus (CCS) reads, including 746,317 full-length nonchimeric (FLNC) reads. The transcript cluster analysis revealed 212,964 consensus sequences, including 203,994 high-quality isoforms. In total, 111,372 of 117,888 transcripts were successfully annotated against eight databases (Nr, eggNOG, Swiss-Prot, GO, COG, KOG, Pfam and KEGG). Furthermore, 23,877 alternative splicing events, 169,128 simple sequence repeats (SSRs), 10,437 lncRNAs and 7,932 transcription factors were predicted across all transcripts. To our knowledge, this report is the first to document the G. gecko transcriptome using SMRT sequencing. The full-length transcript data might accelerate transcriptome research and lay the foundation for further research on G. gecko.

Association between Subjective Body Image, Body Mass Index and Psychological Symptoms in Chinese Adolescents: A Nationwide Cross-Sectional Study.

BACKGROUND: Conflicting findings were reported about the associations between subjective body image (SBI), body mass index (BMI) and psychological symptoms in China and other countries in the world. In this study, we aim to explore the associations between SBI, BMI, and psychological symptoms based on a large-scale, national wide survey among Chinese adolescents. METHODS: The 2014-2015 China Education Panel Survey (CEPS) database, with 8134 middle school students (4137 boys and 3997 girls), was analyzed to explore the association between SBI, BMI and psychological symptoms. SBI was assessed by one question about the perception of own body shape with options "very thin", "slightly thin", "average", "weak heavy", and "very heavy". BMI was calculated by the self-reported body weight and height. Psychological symptoms were evaluated by 10 items involving both aspects of depression and anxiety. RESULTS: The results indicated that both boys and girls who perceived weak or very heavy weight were positively associated with psychological symptoms (p < 0.05). For boys, perceiving very thin body image was also in higher risk of psychological symptoms (p < 0.05), after controlling social-demographic variables and BMI. Comparing with normal weight boys or girls, obese boys (ß = -2.22, 95% CI -3.37~-1.07) and overweight girls (ß = -1.03, 95% CI -2.01~-0.06) were in lower levels of psychological symptoms after controlling for SBI. Other factors associated with psychological symptoms were family economic status, academic performance, and self-rated health status. CONCLUSIONS: A deviation from an "average" SBI was positively associated with psychological symptoms, which should be scanned when evaluating the Chinese adolescents' mental health. These findings provide epidemiological evidence for the association between SBI and psychological symptoms in non-western social contexts.

Psychological Distress Among Chinese College Students During the COVID-19 Pandemic: Does Attitude Toward Online Courses Matter?

Due to the pandemic of coronavirus disease 2019 (COVID-19), taking online courses has become a "new normality" for college students. This study paid particular attention to the role of college students' attitude toward online courses (ATOC) in shaping their psychological distress during the COVID-19 epidemic in China. Participants were from a national panel survey that has been administered before and during the COVID-19 epidemic. Besides bivariate analysis, a multivariate regression model while adjusting for a lagged dependent variable (i.e., pre-COVID distress) was estimated to show the association between ATOC and during-COVID distress. We found that respondents from a disadvantaged family background (i.e., below-college parental education, below-average family economic condition, and rural residence) were more likely to have an "unsupportive" ATOC. Moreover, both bivariate and multivariate analyses confirmed that respondents with a "neutral" or "unsupportive" ATOC had greater during-COVID psychological distress, compared to their counterparts with a "supportive" ATOC. Given the persistent spread of the COVID-19 worldwide and the profound onsite-online transition in course delivery in higher education, students' perceptions and evaluations of the massive online courses should be carefully considered and integrated into curriculum reforms in both present and post COVID-19 situations.

Weight in the mind: Weight perception and depressive symptoms in Chinese adolescents.

BACKGROUND: Increasing evidence demonstrates the significant role of weight perception in shaping the mental health of adolescents. This study sought to extend previous literature by examining the associations of weight perception categories with depressive symptoms for both boys and girls in China, and further explored whether the associations varied between urban and rural areas. METHODS: Data were from a large-scale, national survey of Chinese middle school students. The analytical sample had 8568 respondents with a mean age of 13.9 years (SD=0.7). Bivariate and multiple regression analyses were adopted to examine the links between weight perception and depressive symptoms. RESULTS: Overweight perceptions were more prevalent in girls than in boys (47.0% vs. 29.3%), whereas underweight perceptions were less common in girls than in boys (15.7% vs. 29.3%). After adjusting for sociodemographic characteristics and health conditions, self-perceiving as "slightly overweight" and "very overweight" were significantly related to more depressive symptoms for both boys (p<0.05) and girls (p<0.05). A "very underweight" perception, however, was found to be only linked to greater depressive symptoms in boys (p<0.05). Notably, these patterns showed no significant rural-urban difference, as evidenced by the lack of significant interactive effects of all weight perceptions categories and region (urban/rural) on depressive symptoms. LIMITATIONS: This study was based on a cross-sectional design, which essentially precludes the possibility to determine the causality of the observed associations. CONCLUSION: Findings in this study indicated that the impacts of subjective physical attractiveness have been gendered and regionally pervasive in affecting emotional well-being of Chinese adolescents.

Prevalence and Patterns of Extramarital Sex among Chinese Men and Women: 2000-2015.

Despite growing concern about the "sexual revolution" in China in the past decades, empirical evidence regarding the national trends in prevalence and patterns of extramarital sex (EMS) remains sparse. This study aimed to fill this gap, using data from a population-based, repeated cross-sectional survey administered at four time points during the period 2000-2015. EMS was assessed by asking whether a person in marriage had engaged in sexual activity with someone else during the relationship with his/her current partner. Our findings showed that among married adults aged 20-59, the occurrence rate of EMS nearly tripled over the period 2000-2015, increasing from 12.9% to 33.4% for men, and from 4.7% to 11.4% for women. Moreover, in the early years of this century, EMS was negatively associated with older age (50-59 years), lower educational level (elementary and below) and rural residence for men, and negatively associated with older age and positively associated with higher educational level (college and above) for women. All these differences, however, disappeared in more recent years. Overall, this study indicates a marked increase in EMS, a widening gender gap in EMS, and for each gender, a convergence of EMS across various sociodemographic groups.

Photoswitchable gRNAs for Spatiotemporally Controlled CRISPR-Cas-Based Genomic Regulation.

The recently discovered CRISPR-Cas gene editing system and its derivatives have found numerous applications in fundamental biology research and pharmaceutical sciences. The need for precise external control over the gene editing and regulatory events has driven the development of inducible CRISPR-Cas systems. While most of the light-controllable CRISPR-Cas systems are based on protein engineering, we developed an alternative synthetic approach based on modification of crRNA/tracrRNA duplex (guide RNA or gRNA) with photocaging groups, preventing the gRNA from recognizing its genome target sequence until its deprotection is induced within seconds of illumination. This approach relies on a straightforward solid-phase synthesis of the photocaged gRNAs, with simpler purification and characterization processes in comparison to engineering a light-responsive protein. We have demonstrated the feasibility of photocaging of gRNAs and light-mediated DNA cleavage upon brief exposure to light in vitro. We have achieved light-mediated spatiotemporally resolved gene editing as well as gene activation in cells, whereas photocaged gRNAs showed virtually no detectable gene editing or activation in the absence of light irradiation. Finally, we have applied this system to spatiotemporally control gene editing in zebrafish embryos in vivo, enabling the use of this strategy for developmental biology and tissue engineering applications.

Dynein-mediated microtubule translocation powering neurite outgrowth in chick and Aplysia neurons requires microtubule assembly.

Previously, we have shown that bulk microtubule (MT) movement correlates with neurite elongation, and blocking either dynein activity or MT assembly inhibits both processes. However, whether the contributions of MT dynamics and dynein activity to neurite elongation are separate or interdependent is unclear. Here, we investigated the underlying mechanism by testing the roles of dynein and MT assembly in neurite elongation of Aplysia and chick neurites using time-lapse imaging, fluorescent speckle microscopy, super-resolution imaging and biophysical analysis. Pharmacologically inhibiting either dynein activity or MT assembly reduced neurite elongation rates as well as bulk and individual MT anterograde translocation. Simultaneously suppressing both processes did not have additive effects, suggesting a shared mechanism of action. Single-molecule switching nanoscopy revealed that inhibition of MT assembly decreased the association of dynein with MTs. Finally, inhibiting MT assembly prevented the rise in tension induced by dynein inhibition. Taken together, our results suggest that MT assembly is required for dynein-driven MT translocation and neurite outgrowth.

Geographic variation in body size and its relationship with environmental gradients in the Oriental Garden Lizard, Calotes versicolor.

Patterns of geographic variation in body size are predicted to evolve as adaptations to local environmental gradients. However, many of these clinal patterns in body size, such as Bergmann's rule, are controversial and require further investigation into ectotherms such as reptiles on a regional scale. To examine the environmental variables (temperature, precipitation, topography and primary productivity) that shaped patterns of geographic variation in body size in the reptile Calotes versicolor, we sampled 180 adult specimens (91 males and 89 females) at 40 locations across the species range in China. The MANOVA results suggest significant sexual size dimorphism in C. versicolor (F23,124 = 11.32, p < .001). Our results showed that C. versicolor failed to fit the Bergmann's rule. We found that the most important predictors of variation in body size of C. versicolor differed for males and females, but mechanisms related to heat balance and water availability hypotheses were involved in both sexes. Temperature seasonality, precipitation of the driest month, precipitation seasonality, and precipitation of the driest quarter were the most important predictors of variation in body size in males, whereas mean precipitation of the warmest quarter, mean temperature of the wettest quarter, precipitation seasonality, and precipitation of the wettest month were most important for body size variation in females. The discrepancy between patterns of association between the sexes suggested that different selection pressures may be acting in males and females.

Genetic and Epigenetic Alterations of Brassica nigra Introgression Lines from Somatic Hybridization: A Resource for Cauliflower Improvement.

Broad phenotypic variations were obtained previously in derivatives from the asymmetric somatic hybridization of cauliflower "Korso" (Brassica oleracea var. botrytis, 2n = 18, CC genome) and black mustard "G1/1" (Brassica nigra, 2n = 16, BB genome). However, the mechanisms underlying these variations were unknown. In this study, 28 putative introgression lines (ILs) were pre-selected according to a series of morphological (leaf shape and color, plant height and branching, curd features, and flower traits) and physiological (black rot/club root resistance) characters. Multi-color fluorescence in situ hybridization revealed that these plants contained 18 chromosomes derived from "Korso." Molecular marker (65 simple sequence repeats and 77 amplified fragment length polymorphisms) analysis identified the presence of "G1/1" DNA segments (average 7.5%). Additionally, DNA profiling revealed many genetic and epigenetic differences among the ILs, including sequence alterations, deletions, and variation in patterns of cytosine methylation. The frequency of fragments lost (5.1%) was higher than presence of novel bands (1.4%), and the presence of fragments specific to Brassica carinata (BBCC 2n = 34) were common (average 15.5%). Methylation-sensitive amplified polymorphism analysis indicated that methylation changes were common and that hypermethylation (12.4%) was more frequent than hypomethylation (4.8%). Our results suggested that asymmetric somatic hybridization and alien DNA introgression induced genetic and epigenetic alterations. Thus, these ILs represent an important, novel germplasm resource for cauliflower improvement that can be mined for diverse traits of interest to breeders and researchers.

Family Background, Private Tutoring, and Children's Educational Performance in Contemporary China.

The prevalence of private tutoring is often noted in the literature on education in East Asia. Empirical evidence concerning the causes and consequences of private tutoring, however, is sparse, especially for China. In this article, we draw upon data from the 2010 China Family Panel Studies to explore whether children's tutoring experiences are influenced by family background and whether private tutoring benefits children's educational performance. Our empirical analyses show that higher parental education, higher family income, and fewer siblings are all associated with a higher likelihood of private tutoring and higher levels of spending on it. Furthermore, private tutoring and spending on tutoring are predictive of higher verbal and math performances, although the difference in math performance between children who received private tutoring and those who did not is statistically insignificant after controlling for family background.

The Transition to First Marriage in China, 1966-2008: An Examination of Gender Differences in Education and Hukou Status.

Using retrospective life history data from the 2008 Chinese General Social Survey (CGSS), this study examines the entrance into first marriage in China, a country that has been experiencing profound socioeconomic changes for the past several decades. We examine educational differences across rural and urban regions and across gender as determinants of marriage. Results reveal that for rural women, increasing education (especially from the least educated to middle levels of education) decreases marriage chances. For urban women, increasing education does not affect their marriage chances, net of other factors. For the former, results are consistent with the broad East Asian cultural practice of women "marrying up." For the latter, we argue that modernizing forces (e.g., improvements in education) have reduced the incidence of this practice. We also find effects attributable to unique features of the Chinese institutional context, such as the rural/urban divide and effects of the household registration (Hukou) system.

[DNA barcoding and its utility in commonly-used medicinal snakes].

Identification accuracy of traditional Chinese medicine is crucial for the traditional Chinese medicine research, production and application. DNA barcoding based on the mitochondrial gene coding for cytochrome c oxidase subunit I (COI), are more and more used for identification of traditional Chinese medicine. Using universal barcoding primers to sequence, we discussed the feasibility of DNA barcoding method for identification commonly-used medicinal snakes (a total of 109 samples belonging to 19 species 15 genera 6 families). The phylogenetic trees using Neighbor-joining were constructed. The results indicated that the mean content of G + C(46.5%) was lower than that of A + T (53.5%). As calculated by Kimera-2-parameter model, the mean intraspecies genetic distance of Trimeresurus albolabris, Ptyas dhumnades and Lycodon rufozonatus was greater than 2%. Further phylogenetic relationship results suggested that identification of one sample of T. albolabris was erroneous. The identification of some samples of P. dhumnades was also not correct, namely originally P. korros was identified as P. dhumnades. Factors influence on intraspecific genetic distance difference of L. rufozonatus need to be studied further. Therefore, DNA barcoding for identification of medicinal snakes is feasible, and greatly complements the morphological classification method. It is necessary to further study in identification of traditional Chinese medicine.

Insights from ecological niche modeling on the taxonomic distinction and niche differentiation between the black-spotted and red-spotted tokay geckoes (Gekko gecko).

The black-spotted tokay and the red-spotted tokay are morphologically distinct and have largely allopatric distributions. The black-spotted tokay is characterized by a small body size and dark skin with sundry spots, while the red-spotted tokay has a relatively large body size and red spots. Based on morphological, karyotypic, genetic, and distribution differences, recent studies suggested their species status; however, their classifications remain controversial, and additional data such as ecological niches are necessary to establish firm hypotheses regarding their taxonomic status. We reconstructed their ecological niches models using climatic and geographic data. We then performed niche similarity tests (niche identity and background tests) and point-based analyses to explore whether ecological differentiation has occurred, and whether such differences are sufficient to explain the maintenance of their separate segments of environmental ranges. We found that both niche models of the black- and the red-spotted tokay had a good fit and a robust performance, as indicated by the high area under the curve (AUC) values ("black" = 0.982, SD = ± 0.002, "red" = 0.966 ± 0.02). Significant ecological differentiation across the entire geographic range was found, indicating that the involvement of ecological differentiation is important for species differentiation. Divergence along the environmental axes is highly associated with climatic conditions, with isothermality being important for the "black" form, while temperature seasonality, precipitation of warmest quarter, and annual temperature range together being important for the "red" form. These factors are likely important factors in niche differentiation between the two forms, which result in morphological replacement. Overall, beside morphological and genetic differentiation information, our results contribute to additional insights into taxonomic distinction and niche differentiation between the black- and the red-spotted tokay.

[DNA barcoding of COI gene in some medicinal animals of Lacertilia].

To identify some medicinal animals of Lacertilia, in total 59 individuals belonging to 12 species 7 genera 3 families, we used the universal barcoding primers to sequence these species, compared with other homologous sequences (564 bp) obtaining from the GenBank and finally constructed phylogenetic trees using Neighbor-joining, Maximum parsimony and Bayesian inference, respectively. As a result, the mean content of G + C (46.5%) was lower than that of A + T (53.5%). As calculated by Kimera-2-parameter model, the whole individuals mean distance for interspecies and intraspecies was 35. 5% and 1.7%, respectively. The mean distance for interspecies was 21 times as much as that for intraspecies. The mean distance for intraspecies of Gekko swinhonis, Hemidactylus frenatus and G. gecko was greater than 2%, respectively. Further analyses suggested that geographical groups of the three species might be of different subSpecies, even species. Of course, incorporating morphological characters and other unlinked genetic markers in future studies will offer further insights into the divergence. On the basis of phylogenetic trees constructed by COI, our results indicated that the taxonomy of the category (family, genus, and species) by DNA barcoding is consistent with morphological characters. Therefore, DNA barcoding is a useful tool for both identification and phylogeny of medicinal animals of Lacertilia, particularly for nonprofessor identifying authentication of Chinese crude drugs of these species.