Direct visualization of edge state in even-layer MnBi2Te4 at zero magnetic field.

Being the first intrinsic antiferromagnetic (AFM) topological insulator (TI), MnBi2Te4 is argued to be a topological axion state in its even-layer form due to the antiparallel magnetization between the top and bottom layers. Here we combine both transport and scanning microwave impedance microscopy (sMIM) to investigate such axion state in atomically thin MnBi2Te4 with even-layer thickness at zero magnetic field. While transport measurements show a zero Hall plateau signaturing the axion state, sMIM uncovers an unexpected edge state raising questions regarding the nature of the "axion state". Based on our model calculation, we propose that the edge state of even-layer MnBi2Te4 at zero field is derived from gapped helical edge states of the quantum spin Hall effect with time-reversal-symmetry breaking, when a crossover from a three-dimensional TI MnBi2Te4 to a two-dimensional TI occurs. Our finding thus signifies the richness of topological phases in MnB2Te4 that has yet to be fully explored.

Electronically phase separated nano-network in antiferromagnetic insulating LaMnO3/PrMnO3/CaMnO3 tricolor superlattice.

Strongly correlated materials often exhibit an electronic phase separation (EPS) phenomena whose domain pattern is random in nature. The ability to control the spatial arrangement of the electronic phases at microscopic scales is highly desirable for tailoring their macroscopic properties and/or designing novel electronic devices. Here we report the formation of EPS nanoscale network in a mono-atomically stacked LaMnO3/CaMnO3/PrMnO3 superlattice grown on SrTiO3 (STO) (001) substrate, which is known to have an antiferromagnetic (AFM) insulating ground state. The EPS nano-network is a consequence of an internal strain relaxation triggered by the structural domain formation of the underlying STO substrate at low temperatures. The same nanoscale network pattern can be reproduced upon temperature cycling allowing us to employ different local imaging techniques to directly compare the magnetic and transport state of a single EPS domain. Our results confirm the one-to-one correspondence between ferromagnetic (AFM) to metallic (insulating) state in manganite. It also represents a significant step in a paradigm shift from passively characterizing EPS in strongly correlated systems to actively engaging in its manipulation.

Helical Luttinger Liquid on the Edge of a Two-Dimensional Topological Antiferromagnet.

A boundary helical Luttinger liquid (HLL) with broken bulk time-reversal symmetry belongs to a unique topological class that may occur in antiferromagnets (AFM). Here, we search for signatures of HLL on the edge of a recently discovered topological AFM, MnBi2Te4 even-layer. Using a scanning superconducting quantum interference device, we directly image helical edge current in the AFM ground state appearing at its charge neutral point. Such a helical edge state accompanies an insulating bulk which is topologically distinct from the ferromagnetic Chern insulator phase, as revealed in a magnetic field driven quantum phase transition. The edge conductance of the AFM order follows a power law as a function of temperature and source-drain bias which serves as strong evidence for HLL. Such HLL scaling is robust at finite fields below the quantum critical point. The observed HLL in a layered AFM semiconductor represents a highly tunable topological matter compatible with future spintronics and quantum computation.

Association of pre-pregnancy body mass index with adverse pregnancy outcome among first-time mothers.

BACKGROUND: Studies have reported an increased risk of adverse pregnancy outcome associated with pre-pregnancy body mass index (BMI). However, the data on such associations in urban areas of southern Chinese women is limited, which drive us to clarify the associations of pre-pregnancy BMI and the risks of adverse pregnancy outcomes (preterm birth (PTB) and low birth weight (LBW)) and maternal health outcomes (gestational hypertension and cesarean delivery). METHODS: We performed a hospital-based case-control study including 3,864 Southern Chinese women who gave first birth to a live singleton infant from January 2015 to December 2015. PTB was stratified into three subgroups according to gestational age (extremely PTB, very PTB and moderate PTB). Besides, we combined birth weight and gestational age to dichotomise as being small for gestational age (SGA, less than the tenth percentile of weight for gestation) and non-small for gestational age (NSGA, large than the tenth percentile of weight for gestation), gestational week was also classified into categories of term, 34-36 week and below 34 week.. We then divided newborns into six groups: (1) term and NSGA; (2) 34-36 week gestation and NSGA; (3) below 34 week gestation and NSGA; (4) term and SAG; (5) 34-36 week gestation and SAG; (6) below 34 week gestation and SAG. Adjusted logistic regression models was used to estimate the odds ratios of adverse outcomes. RESULTS: Underweight women were more likely to give LBW (AOR = 1.44, 95% CI [1.11-1.89]), the similar result was seen in term and SAG as compared with term and NSAG (AOR = 1.78, 95% CI [1.45-2.17]), whereas underweight was significantly associated with a lower risk of gestational hypertension (AOR = 0.45, 95% CI [0.25-0.82) and caesarean delivery (AOR = 0.74, 95% CI [0.62-0.90]). The risk of extremely PTB is relatively higher among overweight and obese mothers in a subgroup analysis of PTB (AOR = 8.12, 95% CI [1.11-59.44]; AOR = 15.06, 95% CI [1.32-172.13], respectively). Both maternal overweight and obesity were associated with a greater risk of gestational hypertension (AOR = 1.71, 95% CI [1.06-2.77]; AOR = 5.54, 95% CI [3.02-10.17], respectively) and caesarean delivery (AOR = 1.91, 95% CI [1.53-2.38]; AOR = 1.85, 95% CI [1.21-2.82], respectively). CONCLUSIONS: Our study suggested that maternal overweight and obesity were associated with a significantly higher risk of gestational hypertension, caesarean delivery and extremely PTB. Underweight was correlated with an increased risk of LBW and conferred a protective effect regarding the risk for gestational hypertension and caesarean delivery for the first-time mothers among Southern Chinese.

A study of entity-linking methods for normalizing Chinese diagnosis and procedure terms to ICD codes.

OBJECTIVE: This study aims to develop and evaluate effective methods that can normalize diagnosis and procedure terms written by physicians to standard concepts in International Classification of Diseases(ICD) in Chinese, with the goal to facilitate automated medical coding in China. METHODS: We applied the entity-linking framework to normalize Chinese diagnosis and procedure terms, which consists of two steps - candidate concept generation and candidate concept ranking. For candidate concept generation, we implemented both the traditional BM25 algorithm and an extended version that integrates a synonym knowledgebase. For candidate concept ranking, we investigated a number of different algorithms: (1) the BM25 algorithm, (2) ranking support vector machines (RankSVM), (3) a previously reported Convolutional Neural Network (CNN) approach, (4) 11 deep ranking-based methods from the MatchZoo toolkit, and (5) a new BERT (Bidirectional Encoder Representations from Transformers) based ranking method. Using two manually annotated datasets (8,547 diagnoses and 8,282 procedures) collected from a Tier 3A hospital in China, we evaluated above methods and reported their performance (i.e., accuracy) at different cutoffs. RESULTS: The coverage of candidate concept generation was greatly improved after integrating the synonym knowledgebase, achieving 97.9% for diagnoses and 93.4% for procedures respectively. Overall the new BERT-based ranking method achieved the best performance on both diagnosis and procedure normalization, with the best accuracy of 92.1% for diagnosis and 80.1% for procedure, when the top one concept and exact match criteria were used. CONCLUSIONS: This study developed and compared diverse entity-linking methods to normalize clinical terms in Chinese and our evaluation shows good performance on mapping disease terms to ICD codes, demonstrating the feasibility of automated encoding of clinical terms in Chinese.

Association of induced abortion with preterm birth risk in first-time mothers.

Women who have previously had an induced abortion (IA) before their first birth have been associated with preterm birth (PTB). However, previous studies on the PTB are inconsistent. Therefore, the aim of this study was to clarify the association between IA and PTB and low birth weight (LBW) for first-time mothers. A total of 3,684 Southern Chinese women who gave birth for the first time to a live singleton infants were recruited between January 2015 and December 2015 in the province of Guangdong, China. Univariable and multivariable analyses were conducted to determine whether IA was associated with PTB and LBW. Previous IA was not associated with increased risks of PTB or LBW, adjusted odds ratios were 0.80 (95% CI = 0.53 to 1.20) and 0.86 (95% CI = 0.57 to 1.31), respectively. Additionally, no significant associations were observed for infants born at before 37, before 32, and before 28 gestational weeks. And no significant associations were also observed for LBW measuring lower than 2500 grams and also measuring lower than 1500 grams. Our study suggested that a previous IA, as compared with women who reported no previous IA, does not increase the risk of PTB or LBW in subsequent pregnancy for the first-time mothers among Southern Chinese women.

High Expression of Mannose-Binding Lectin and the Risk of Vascular Complications of Diabetes: Evidence from a Meta-Analysis.

BACKGROUND: Vascular inflammation associated with mannose-binding lectin (MBL) may be implicated in the pathogenesis of vascular complications in diabetes. The purpose of this study is to evaluate the association of MBL expression with vascular complications in diabetes. MATERIALS AND METHODS: Data from published case-control studies on MBL expression and vascular complications of diabetes were collected up to September 30, 2014. Medline, Embase, and Chinese National Knowledge Infrastructure (CNKI) were searched using the key words "MBL or mannose-binding lectin or mannan-binding lectin," "diabetes or diabetic," and "vascular complication, vascular disease or angiopathy" to identify the articles published in English or Chinese. RESULTS: The combined odds ratio (OR) and 95% confidence interval (CI) for the cumulative rate of vascular complications in the cases of high-expression MBL versus that in cases of low-expression MBL were estimated using a fixed-effects model and a random-effects model. In total, 2,714 cases from 12 articles including 2,256 cases with high-expression MBL (≥ 400 µg/L) and 458 cases with low-expression MBL (< 400 µg/L) were reviewed. The cumulative vascular complication rates were 52.9% (1,194/2,256) in the cases with high expression and 38.4% (176/458) in those with low expression. The combined ORs were 1.6, with a 95% CI ranging from 1.24 to 2.08, in the fixed-effects model and 1.94, with a 95% CI from 1.00 to 3.76, in the random-effects model. CONCLUSIONS: High expression of MBL may be correlated with a significantly increased risk of vascular complications in diabetes. Thus MBL detection in diabetes is an effective and feasible method to predict vascular complications.

Rubella Seroprevalence among the General Population in Dongguan, China.

In order to assess the immunity to rubella infection in Dongguan, China, we conducted a seroprevalence survey on rubella and used ELISA to measure rubella-specific IgG in serum samples. A total of 1,017 individuals aged 0-59 years were selected by multistage cluster sampling. Among them, 904 (88.9%) were seropositive for rubella. Two groups (20-29 and ≥40 years) had seropositivity rates of <90%. In comparison with participants aged ≥20 years, rubella immunization rates were higher in those aged <20 years (83.2% vs. 93.7%, respectively; χ(2) = 28.063, P < 0.001). Among women aged 20-29 years, only 63.8% had antibodies above the protective level. Multivariate analysis revealed that only sex and age were significantly associated with rubella-protective antibody levels. Our results suggest that in the study area, women of childbearing age had a greater serological susceptibility to rubella. Additional vaccinations for rubella of susceptible young adults should be considered, particularly in women of childbearing age.

Age-related changes in serological susceptibility patterns to measles: results from a seroepidemiological study in Dongguan, China.

The present study was performed to determine the seroprevalence of IgG measles antibodies in Dongguan residents (irrespective of vaccination status), to analyze the changes in age-related serological susceptibility patterns. A total of 1960 residents aged 0-60 years and 315 mother-infant pairs were studied. Serum IgG antibodies against measles virus were measured by ELISA. The overall seroprevalence was 93.4% in the general population in Dongguan, China. In subgroups aged 1-29 years who were likely vaccinated, there was a declining trend of seropositivity with age from 98.6% at 1-4 years to 85.7% at 20-29 years (P<0.0001). Seroprevalence were near or>95% in the older population (30-39 years and ≥ 40 years) who had not been immunized against measles. Age and sex were independent factors associated with seropositivity. Seroprevalence in pregnant women and their newborns was 87.0% and 84.1%, respectively. Our results suggest that the waning vaccine-induced immunity may be the main cause of increased serological susceptibility in young adults and young infants. An additional vaccination strategy that targets young adults is important for elimination of measles.

Factors associated with delayed measles vaccination among children in Shenzhen, China: a case-control study.

A delay in the first dose of measles-containing vaccine (MCV1) may contribute to outbreaks of measles, resulting in a high age-specific incidence in infants<1 y of age. To determine the factors associated with delayed MCV1 vaccinations, we used data from the China Information Management System for Immunization Programming. Additionally, the parents/guardians of 430 children whose MCV1 vaccinations were delayed, as well as the parents/guardians of 424 children who received timely vaccinations, were surveyed by telephone. Children were less likely to receive timely MCV1 vaccinations if they belonged to an immigrant group, were male, had poor health status, had a father whose occupation e.g., a manager, had a history of delays in other Expanded Programs on Immunization (EPI) vaccinations, had parents who did not believe vaccinations were important for their children, and experienced shorter travel times to and longer waiting times in EPI clinics. The children of mothers whose occupational status (technician) were more likely to receive timely MCV1 vaccinations. The timeliness of MCV1 vaccinations should be considered as an additional indicator of the quality of vaccination programs.

Association between microRNA polymorphisms and humoral immunity to hepatitis B vaccine.

To investigate whether selected single nucleotide polymorphisms (SNPs) in miR-146a, miR-196a2, miR-27a, miR-26a-1, miR-124 and miR-149 genes are associated with immune response to hepatitis B vaccine. The genotype and allele frequencies of SNPs were compared between the non-responders (n=77) and responders (n=207). The associations of the genotypes with antibody levels were assessed in the responders. Significant associations were observed between SNPs in miR-146a and miR-26a-1 genes and non-response to hepatitis B vaccine (p<0.05). In addition, SNPs in miR-146a and miR-27a genes were associated with variations in levels of antibodies to hepatitis B antigen. Thus, specific SNPs in microRNAs (miRNAs) genes may affect status of the hepatitis B vaccine induced protective humoral immune response. They also suggest that the three miRNAs play a role in modulating antibody responses to hepatitis B vaccine.

Increased serum microRNA-155 level associated with nonresponsiveness to hepatitis B vaccine.

We compared the serum levels of microRNA-155 (miR-155) between subjects with normal response to hepatitis B vaccine and nonresponders. Results showed that serum expression of miR-155 was significantly higher in nonresponders than in responders (6.40 versus 2.55; Z = 2.125, P = 0.034), suggesting that overexpression of miR-155 is correlated with nonresponsiveness to hepatitis B vaccine.