Association between white blood cell count and adverse pregnancy outcomes: a retrospective cohort study from a tertiary hospital in China.

OBJECTIVES: This study aimed to clarify the relationship between white blood cell (WBC) and adverse pregnancy outcomes. DESIGN: A total of 25 270 pregnant women underwent peripheral blood white blood cell count tests in the first, second and third trimesters. Adverse pregnancy outcomes were gestational hypertension, pre-eclampsia, gestational diabetes mellitus, preterm birth, low birth weight, caesarean delivery, macrosomia and fetal distress. Due to acute infectious disease or other diseases, 1127 were excluded. SETTING: Minhang Hospital, China. PARTICIPANTS: A total of 24 143 pregnant women were included in this study. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the adverse pregnancy outcomes. RESULTS: For the 24 143 participants, we calculated adjusted ORs for adverse pregnancy outcomes associated with an increased WBC count. For gestational hypertension, the ORs were 1.18 (95% CI, 1.05 to 1.24) in the first trimester and 1.10 (1.06 to 1.13) in the second trimester; for pre-eclampsia, ORs were 1.14 (95% CI, 1.47 to 1.64) in the first trimester and 1.10 (1.05 to 1.16) in the second trimester; for gestational diabetes mellitus, ORs were 1.06 (95% CI, 1.00 to 1.13) in the first trimester and 1.10 (1.04 to 1.16) in the second trimester; for preterm birth, ORs were 1.12 (95% CI, 1.06 to 1.18) in the first trimester, 1.10 (1.06 to 1.13) in the second trimester and 1.12 (1.09 to 1.15) in the third trimester; for low birth weight, ORs were 1.09 (95% CI, 1.02 to 1.17) in the first trimester, 1.03 (0.99 to 1.08) in the second trimester and 1.12 (1.08 to 1.16) in the third trimester. Significant associations were not observed obviously for caesarean delivery, macrosomia and fetal distress. CONCLUSIONS: Our results indicate strong, continuous associations of maternal WBC count with increased risks of adverse pregnancy outcomes.

Tapered Quantum Cascade Laser Arrays Integrated with Talbot Cavities.

Power scaling in broad area quantum cascade laser (QCL) usually leads to the deterioration of the beam quality with an emission of multiple lobes far-field pattern. In this letter, we demonstrate a tapered QCL array integrated with Talbot cavity at one side of the array. Fundamental supermode operation is achieved in the arrays with taper straight-end connected to the Talbot cavity. Lateral far-field of the fundamental supermode shows a near diffraction limited beam divergence of 2.7°. The output power of a five-element array is about three times as high as a single-ridge laser with an emission wavelength of around 4.8 µm. However, arrays with the taper-end connected to the Talbot cavity always show a high-order supermode operation whatever Talbot cavity length is.

Low Power Consumption Substrate-Emitting DFB Quantum Cascade Lasers.

In the present work, an ultra-low power consumption substrate-emitting distributed feedback (DFB) quantum cascade laser (QCL) was developed. The continuous-wave (CW) threshold power dissipation is reduced to 0.43 W at 25 °C by shortening the cavity length to 0.5 mm and depositing high-reflectivity (HR) coating on both facets. As far as we know, this is the recorded threshold power dissipation of QCLs in the same conditions. Single-mode emission was achieved by employing a buried second-order grating. Mode-hop free emission can be observed within a wide temperature range from 15 to 105 °C in CW mode. The divergence angles are 22.5o and 1.94o in the ridge-width direction and cavity-length direction, respectively. The maximum optical power in CW operation was 2.4 mW at 25 °C, which is sufficient to spectroscopy applications.

Phase-locked array of quantum cascade lasers with an integrated Talbot cavity.

We show a phase-locked array of three quantum cascade lasers with an integrated Talbot cavity at one side of the laser array. The coupling scheme is called diffraction coupling. By controlling the length of Talbot to be a quarter of Talbot distance (Zt/4), in-phase mode operation can be selected. The in-phase operation shows great modal stability under different injection currents, from the threshold current to the full power current. The far-field radiation pattern of the in-phase operation contains three lobes, one central maximum lobe and two side lobes. The interval between adjacent lobes is about 10.5°. The output power is about 1.5 times that of a single-ridge laser. Further studies should be taken to achieve better beam performance and reduce optical losses brought by the integrated Talbot cavity.

[Pretreatment Research Based on Left and Right Hand Motor Imagery for Single-channel Electroencephalogram].

Most of electroencephalogram(EEG)acquired by multi-channels is difficult to be applied to the singlechannel brain-computer interface(BCI)in the EEG analysis method based on left and right hand motor imagery.The present research applied an improved independent component analysis(ICA)method to realize pretreatment of the EEG effectively.Firstly,data drift was removed through linear drift correction.Secondly,the number of virtual channels were increased by applying delayed window data and some EEG artifacts which are namely electrooculogram(EOG)and electrocardiogram(ECG)were removed by ICA.Finally,the average instantaneous energy characteristics were calculated and classified through the instantaneous amplitude which was solved by applying Hilbert-Huang transform(HHT).The experiment proves that the method completes the EEG pretreatment and improves classification ratio of single-channel EEG,and lays a foundation of single-channel and portable BCI.