Genetic and Molecular Characterization of Flagellar Assembly in Shewanella oneidensis

Shewanella oneidensis is a highly motile organism by virtue of a polar flagellum. Unlike most flagellated bacteria, it contains only one major chromosome segment encoding the components of the flagellum with the exception of the motor proteins. In this region, three genes encode flagellinsaccording to the original genome annotation. However, we find that only flaA and flaB encode functional filament subunits. Although these two genesare under the control of different promoters, they are actively transcribed and subsequently translated, producing a considerable number of flagellin proteins. Additionally, both flagellins are able to interact with their chaperon FliS and are subjected to feedback regulation. Furthermore, FlaA and FlaB are glycosylated by a pathwayinvolving a major glycosylating enzyme,PseB, in spite of the lack of the majority of theconsensus glycosylation sites. In conclusion, flagellar assembly in S. oneidensis has novel features despite the conservation of homologous genes across taxa

Network structure of emotional and behavioral problems, loneliness, and suicidal thoughts in adolescents at the school closure and reopening stage in China

BACKGROUND: Public restriction and school closure policies during the pandemic may have long-term effects on adolescents' mental health, and adolescents' feelings and needs may change as the pandemic progresses. This study was conducted to explore the network structure and differences in emotional and behavioral problems (EBPs), loneliness, and suicidal thoughts in adolescents during different pandemic periods in China. METHODS: Based on two cross-sectional studies conducted in Taizhou, China, during school closure (April 16 to May 14, 2020) and reopening (May 25 to July 10, 2021) using online questionnaire, a total of 14,726 adolescents (school closure: 6,587, school reopening: 8,139) were recruited. EBPs were evaluated based on the student version of the Strengths and Difficulties Questionnaire (SDQ). Loneliness and suicidal thoughts were measured by item 20 and item 9 of the Chinese version of the Children's Depression Inventory (CDI), respectively. Network analysis was used to estimate the network connections and properties between EBPs, loneliness, and suicidal thoughts. RESULTS: The prevalence of psychosocial problems significantly increased at the school reopening compared with the school closure: EBPs: 36.8% vs. 31.6%; loneliness: 40.3% vs. 33.9%; suicidal thoughts: 40.8% vs. 15.4%. Suicidal thoughts showed the closest connections with being unhappy and lonely. Being bullied was strongly connected with conduct problems of lying and stealing. The links between hyperactivity symptoms and the other domains of EBPs were stronger after the school reopened. Being unhappy and showing the hyperactivity symptoms of "nonpersistent, distractible, and fidgety" presented high network and bridge (increasing transference from one symptom domain to another) centrality. Loneliness showed high expected influence and bridge centrality. CONCLUSIONS: This study highlighted the high prevalence of EBPs, loneliness, and suicidal thoughts in Chinese adolescents. It also presented the network structure of these psychological problems over different pandemic stages. It is recommended that psychological support should be provided for adolescents, especially focusing on the central and bridge symptoms highlighted in this study

Machine learning-driven ontological knowledge base for bridge corrosion evaluation

In bridge maintenance, assessing structural performance requires adherence to rules outlined in safety and regulatory standards which can be effectively and formally represented in both human and machine-readable formats using ontologies. However, ontology-based semantic inference alone falls short when faced with the complicated mathematical operations required for structural analysis. The increasing digitization of bridge engineering has opened doors to data-driven prediction methods. Machine learning (ML)-based models, in particular, have the capacity to learn from historical data and forecast future structural performance with remarkable accuracy. This paper introduces an innovative approach that integrates ML models with an ontological knowledge base for evaluating bridge corrosion. Web Ontology Language and Semantic Web Rule Language are combined to develop the knowledge base. Random forest algorithm is used to train the ML model with a good agreement (coefficient of determination of 0.989 and root mean square error of 1.200). A Python-based module is designed to seamlessly integrate ML predictions with ontology-based semantic inference. The proposed approach not only infers the corrosion ratings based on the rules defined in the Network Rail standard, but also infers the structural safety performance based on predicted structural response under the action of corrosion. To demonstrate the effectiveness of the developed method in enabling accurate and rational evaluations, a real bridge in the UK is showcased as a practical application

Number of Courses, Content of Coursework, and Prior Achievement as Related to Ethnic Achievement Gaps in Mathematics

This study utilized base-year and second follow-up data from the National Educational Longitudinal Study of 1988 to investigate the relationship between eighth-grade math achievement, mathematics course-taking in high school, and twelfth-grade math achievement. Results suggested the following: 1) Type of coursework can be quantified. 2) Type of coursework was more predictive of achievement than amount. 3) There were substantial ethnic achievement differences prior to high school. 4) Number of courses, type of courses, and prior achievement were not equally predictive of twelfth-grade mathematics achievement across ethnic groups. 5) Prior achievement did not equally predict course-taking over ethnic groups in amount or type. 6) Closing ethnic achievement gaps will be a function of efforts taken before high school as well as high school coursework

Loneliness and depressive symptoms among men who have sex with men in China: A cross-sectional study

BackgroundWhile psychosocial problems and their related factors in men who have sex with men (MSM) have been well documented in developed countries, there are still not many studies addressing this issue in China and the results are inconsistent. This study aimed to assess the prevalence of loneliness and depressive symptoms among MSM, examine their associated factors, and investigate potential factors moderating the link between depressive symptoms and loneliness.MethodsA cross-sectional study was conducted in Taizhou of Zhejiang Province in China between April and November 2021. Loneliness was assessed using the 3-item UCLA Loneliness Scale (UCLA-3), and depressive symptoms were measured using the Patient Health Questionaire-9 (PHQ-9). Data from 655 MSM were eligible for analysis. Logistic regression models were used to examine the associations between independent variables and the outcomes of loneliness and depression. The interaction terms were added in the models to assess the moderating effects.ResultsOf the MSM sample, 13.28 and 7.48% perceived loneliness and reported moderate-to-severe depressive symptoms, respectively. We found that participants who experienced loneliness were more likely to have younger age (OR 0.44, 95% CI 0.21, 0.93, 15–32 years as reference group), low social support (OR 3.60, 95% CI 2.14, 6.04), low self-esteem (OR 3.03, 95% CI 1.45, 6.32) and moderate-to-severe depressive symptoms (OR 5.45, 95% CI 2.66, 11.15). The participants with moderate-to-severe depressive symptoms were more likely to have low self-esteem (OR 6.78, 95% CI 3.08, 14.95) and feelings of loneliness (OR 5.51, 95% CI 2.66, 11.40). Stratified analyzes showed that the magnitude of the associations between depressive symptoms and loneliness varied in MSM with different age, marital status, and self-esteem.ConclusionOur study suggests that we need to pay attention to feelings of loneliness and depressive symptoms and their closely associated factors such as social support and self-esteem among MSM in China. The MSM who were young, not married, and had low self-esteem were especially vulnerable to the impact of depressive symptoms on loneliness

Correlation between self-esteem and stress response in Chinese college students: The mediating role of the need for social approval

The need for social approval Internal locus of control Mediation analysis a b s t r a c t Interpersonal theories of self-esteem assume that the importance that others place on oneself contributes to individual levels of self-esteem. Recent studies further suggest a possible link between self-esteem and the endocrine stress response, mediated through individual levels of locus of control, without taking levels of social approval into account. The present set of studies aimed to explore the correlation between self-esteem and stress response in Chinese students, and simultaneously take into account the possible mediating role of internal locus of control and need for social approval. In study one, twenty-eight college students' heart rates and saliva samples were collected while they underwent the Trier Social Stress Test (TSST). Their self-esteem scores were assessed using the Rosenberg self-esteem scale. Results showed a positive correlation between self-esteem and their endocrine stress responses to the TSST. In study two, forty-one college students' heart rates were collected while they underwent the TSST. Their locus of control scores were assessed by the Internality, Powerful Others, and Chance Scale, and their social approval scores were assessed by the Marlowe-Crowne Social Desirability Scale. Results indicated a significant positive correlation between self-esteem and heart rate changes during the TSST, with a mediating role of the need for social approval in the association between self-esteem and heart rate stress responses. We speculate that cultural differences may moderate the association between self-esteem and stress response

Functional interplay between SA1 and TRF1 in telomeric DNA binding and DNA-DNA pairing

Proper chromosome alignment and segregation during mitosis depend on cohesion between sister chromatids. Cohesion is thought to occur through the entrapment of DNA within the tripartite ring (Smc1, Smc3 and Rad21) with enforcement from a fourth subunit (SA1/SA2). Surprisingly, cohesin rings do not play a major role in sister telomere cohesion. Instead, this role is replaced by SA1 and telomere binding proteins (TRF1 and TIN2). Neither the DNA binding property of SA1 nor this unique telomere cohesion mechanism is understood. Here, using single-molecule fluorescence imaging, we discover that SA1 displays two-state binding on DNA: searching by one-dimensional (1D) free diffusion versus recognition through subdiffusive sliding at telomeric regions. The AT-hook motif in SA1 plays dual roles in modulating non-specific DNA binding and subdiffusive dynamics over telomeric regions. TRF1 tethers SA1 within telomeric regions that SA1 transiently interacts with. SA1 and TRF1 together form longer DNA-DNA pairing tracts than with TRF1 alone, as revealed by atomic force microscopy imaging. These results suggest that at telomeres cohesion relies on the molecular interplay between TRF1 and SA1 to promote DNA-DNA pairing, while along chromosomal arms the core cohesin assembly might also depend on SA1 1D diffusion on DNA and sequence-specific DNA binding

Impact of charged ionic species (NaCl and KCl) on the generation of color and volatile aroma compounds during caramelization

During the process of caramelization, volatile and non-volatile flavor and color are generated via the degradation of carbohydrates. This research investigated the effect of the types and concentrations of salts including NaCl and KCl on the generation of volatile aromas and color during caramelization. The solid phase microextraction-gas chromatograph-mass spectrometry (SPME-GC-MS) was used to measure the volatile compounds generated in caramelization. The results demonstrated that increasing content of salt (NaCl or KCl) could significantly improve (P<0.05) the generation of some essential volatile compounds during caramelization such as furfural, 5-methylfurfural, 5-hydroxymethyl-furfural (HMF), propionic acid and butyric acid. However, the ascending amount of salt (NaCl or KCl) had no significant impact (P<0.05) on the color generation of caramel. In conclusion, the usage of salt was beneficial to the generation of more aromatic compounds during caramelization

Herpes simplex virus infections among rural residents in eastern China

<p>Abstract</p> <p>Background</p> <p>Herpes simplex virus (HSV) has two types: HSV-1 and HSV-2. Both infect epithelial cells and establish latent infections in neurons causing an infection that persists for life. Information on age- and gender-specific seroprevalence of HSV-1 and HSV-2 is valuable for understanding HSV transmission dynamics and designing population-based prevention and intervention programs for HSV. However, such information is not available for China.</p> <p>Methods</p> <p>Cryopreserved serum samples of all subjects aged 5 to 60 years from two randomly selected rural villages in Zhejiang province in Eastern China who had participated in the China national seroepidemiological survey of hepatitis B virus (HBV) infection conducted in 2006 were tested. Seroprevalence of HSV-1 and HSV-2 infections were determined by type-specific IgG antibody tests using an ELISA technique. Their 95% confidence intervals adjusted for the sampling fraction were calculated according to the Clopper-Pearson method.</p> <p>Results</p> <p>A total of 2,141 residents participated in the survey, with a response rate of 82.3%. HSV-1 seroprevalence was 92.0% overall, 89.1% for males and 94.2% for females. HSV-1 seroprevalence was 61.6% among children aged 5-9 years, 90.3% among 25-29 years, and nearly 100% among those aged > = 40 years. HSV-2 seroprevalence was 13.2% overall, 10.5% for males and 15.3% for females. No children aged 5-14 years were HSV-2 positive, and HSV-2 seroprevalence was 7.1% among 15-19 years and peaked at 24.3% among those aged 45-49 years. Neither HSV-1 nor HSV-2 infections were significantly different by gender. About 11.8% of study subjects were co-infected with both types of HSV. Among 549 participating couples, 8.6% were HSV-1 serodiscordant and 11.8% were HSV-2 serodiscordant. No one tested positive for HIV. The overall prevalence of HBsAg was 16.2%, 16.9% for males and 15.4% for females.</p> <p>Conclusions</p> <p>HSV-1 was highly prevalent among all rural residents aged between 5-60 years in Eastern China, whereas HSV-2 was prevalent among sexually active people. HSV-1 and HSV-2 have different transmission modes and dynamics. Future HSV prevention and control programs in China should be type specific.</p