[Analysis of incidence and associated factors of preterm birth based on pre-pregnancy body mass index stratification].

Objective: To analyze the incidence of preterm birth based on pre-pregnancy body mass index (BMI) stratification and explore the associated factors of preterm birth among pregnant women at different BMI stratifications. Methods: From February 2018 to December 2020, pregnant women who participated in China Birth Cohort Study (CBCS) and gave birth at Beijing Obstetrics and Gynecology Hospital were enrolled as the study subjects. Electronic Data Capture System and standard structured questionnaires were used to collect data related to pre-pregnancy, pregnancy, and delivery for pregnant women. Pregnant women were divided into the low-weight group, normal-weight group and overweight group based on their pre-pregnancy BMI. A Cox proportional hazards model was used to analyze the associated factors of preterm birth among pregnant women with different BMI before pregnancy. Results: A total of 27 195 singleton pregnant women were included, with a preterm birth rate of 5.08% (1 381/27 195). The preterm birth rates in the low-weight group, normal-weight group and overweight group were 4.29% (138/3 219), 4.63% (852/18 390) and 7.00% (391/5 586) respectively (P<0.001). After adjusting for relevant factors, the Cox proportional hazards model showed that the risk of preterm birth in the overweight group was 1.457 times higher than that in the normal-weight group (95%CI: 1.292-1.643). Preeclampsia-eclampsia (HR=2.701, 95%CI: 1.318-5.537) was the associated factor for preterm birth in the low-weight group. Advanced maternal age (HR=1.232, 95%CI: 1.054-1.441), history of preterm birth (HR=4.647, 95%CI: 3.314-6.515), vaginal bleeding in early pregnancy (HR=1.613, 95%CI: 1.380-1.884), and preeclampsia-eclampsia (HR=3.553, 95%CI: 2.866-4.404) were associated factors for preterm birth in the normal-weight group. Advanced maternal age (HR=1.473, 95%CI: 1.193-1.818), history of preterm birth (HR=3.209, 95%CI: 1.960-5.253), vaginal bleeding in early pregnancy (HR=1.636, 95%CI: 1.301-2.058), preeclampsia-eclampsia (HR=2.873, 95%CI:2.265-3.643), and pre-gestational diabetes mellitus (HR=1.867, 95%CI: 1.283-2.717) were associated factors for preterm birth in the overweight group. Conclusion: Pre-pregnancy overweight is an associated factor for preterm birth, and there are significant differences in the associated factors of preterm birth among pregnant women with different BMI before pregnancy.

[Association between coagulation function indicators and placental abruption among preeclampsia-eclampsia pregnant women].

Objective: To explore the association between coagulation function indicators and placental abruption (PA) in different trimesters of pregnancy among preeclampsia-eclampsia pregnant women. Methods: From February 2018 to December 2020, pregnant women who participated in the China birth cohort study and were diagnosed with preeclampsia, eclampsia and chronic hypertension with superimposed preeclampsia in Beijing Obstetrics and Gynecology Hospital were enrolled in this study. The baseline and follow-up information were collected by questionnaire survey, and the coagulation function indicators in the first and third trimesters were obtained through medical records. The Cox proportional hazards model was used to analyze the association between the coagulation function indicators and PA. A restrictive cubic spline curve was used to draw the dose-response curve between the relevant coagulation function indicators and PA. Results: A total of 1 340 participants were included in this study. The age was (32.50±4.24) and the incidence of PA was 4.4% (59/1 340). After adjusting for relevant factors, Cox proportional hazards model showed that compared with the high-level classification of fibrinogen (FIB), participants within the middle-(HR=3.28, 95%CI: 1.27-8.48) and low-level (HR=3.84, 95%CI: 1.40-10.53) classification during the first trimester and within the low-level classification (HR=4.18, 95%CI: 1.68-10.39) during the third trimester were more likely to experience PA. Compared with the middle-level classification of pro-thrombin time (PT), the risk of PA in the participants within the low-level classification (HR=2.67, 95%CI: 1.48-4.82) was significantly higher in the third trimester. The restrictive cubic spline analysis showed a linear negative association between FIB and PA in the first and third trimesters, while PT and PA showed an approximately L-shaped association. Conclusion: Among pregnant women diagnosed with preeclampsia-eclampsia, the middle-and low-level classification of FIB in the first and third trimesters and the low-level classification of PT in the third trimester could increase the risk of PA.

Hamiltonian Engineering with Multicolor Drives for Fast Entangling Gates and Quantum Crosstalk Cancellation.

Quantum computers built with superconducting artificial atoms already stretch the limits of their classical counterparts. While the lowest energy states of these artificial atoms serve as the qubit basis, the higher levels are responsible for both a host of attractive gate schemes as well as generating undesired interactions. In particular, when coupling these atoms to generate entanglement, the higher levels cause shifts in the computational levels that lead to unwanted ZZ quantum crosstalk. Here, we present a novel technique to manipulate the energy levels and mitigate this crosstalk with simultaneous off-resonant drives on coupled qubits. This breaks a fundamental deadlock between qubit-qubit coupling and crosstalk. In a fixed-frequency transmon architecture with strong coupling and crosstalk cancellation, additional cross-resonance drives enable a 90 ns CNOT with a gate error of (0.19±0.02)%, while a second set of off-resonant drives enables a novel CZ gate. Furthermore, we show a definitive improvement in circuit performance with crosstalk cancellation over seven qubits, demonstrating the scalability of the technique. This Letter paves the way for superconducting hardware with faster gates and greatly improved multiqubit circuit fidelities.

[Chemical constituents from the bark of Hibiscus syriacus L].

Seven constituents (I-VII) were isolated from the bark of Hibiscus syriacus and identified as nonanedioic acid (I), suberic acid (II), 1-octarcosanol (III), beta-sitosterol (IV), 1,22-docosanediol (V), betulin (VI) and erythrotriol (VII). VII was obtained from the plant for the first time, I, II, III and VI were isolated from Malvaceae plants for the first time.