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Objective To investigate the association of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) viral load and infection‐to‐delivery interval with maternal and cord serum concentrations of anti‐SARS‐CoV‐2 immunoglobulin G (IgG) antibodies and transplacental transfer ratio in pregnant women with active or recovered SARS‐CoV‐2 infection. Methods This was a prospective case series of consecutive pregnant women with laboratory‐confirmed SARS‐CoV‐2 infection between 27 March 2020 and 24 January 2021. We collected information regarding deep throat saliva or nasopharyngeal swab (NPS) reverse transcription polymerase chain reaction (RT‐PCR) test results, serial cycle threshold (Ct) values at and after diagnosis, demographic, clinical and outcome data, and neonatal NPS RT‐PCR results. Qualitative and quantitative analysis of IgG and immunoglobulin M (IgM) antibodies against SARS‐CoV‐2 was performed in maternal and cord blood serum samples obtained at delivery. Correlation of maternal Ct values, infection‐to‐delivery interval, infection duration and viral load area under the curve (AUC) with gestational age (GA) at diagnosis, maternal and cord serum IgG concentrations and transplacental transfer ratio of IgG were evaluated using Pearson's correlation. Results Twenty pregnant women who consented to participate and who had delivered their babies by 31 January 2021 were included in the study, comprising 14 who had recovered from coronavirus disease 2019 (COVID‐19) and six with active infection at delivery. The median GA at clinical manifestation was 32.7 (range, 11.9–39.4) weeks. The median infection‐to‐delivery interval and infection duration were 41.5 (range, 2–187) days and 10.0 (range, 1–48) days, respectively. The median GA at delivery was 39.1 (range, 32.4–40.7) weeks and the median seroconversion interval was 14 (range, 1–19) days. Of 13 neonates born to seropositive mothers with recovered infection at delivery, 12 tested positive for anti‐SARS‐CoV‐2 IgG. All neonatal NPS samples were negative for SARS‐CoV‐2 and all cord sera tested negative for IgM. The median transplacental transfer ratio of IgG was 1.3 (interquartile range, 0.9–1.6). There was a negative correlation between infection‐to‐delivery interval and anti‐SARS‐CoV‐2 IgG concentrations in maternal (r = –0.6693, P = 0.0087) and cord (r = –0.6554, P = 0.0068) serum and a positive correlation between IgG concentration in maternal serum and viral load AUC (r = 0.5109, P = 0.0310). A negative correlation was observed between transfer ratio and viral load AUC (r = –0.4757, P = 0.0409). Conclusions In pregnant women who have recovered from COVID‐19, anti‐SARS‐CoV‐2 IgG concentrations at delivery increased with increasing viral load during infection and decreased with increasing infection‐to‐delivery interval. The median transplacental transfer ratio of IgG was 1.3 and it decreased with increasing viral load during infection. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Histopathology based on formalin-fixed and paraffin-embedded tissues remains the gold standard for surgical margin assessment (SMA). However, routine pathological practice is lengthy and laborious, failing to provide immediate feedback to surgeons and pathologists for intraoperative decision-making. In this report, we propose a cost-effective and easy-to-use histological imaging method with speckle illumination microscopy (i.e., HiLo). HiLo can achieve rapid and non-destructive imaging of large and fluorescently-labelled resection tissues at an acquisition speed of 5 cm2/min with 1.3-μm lateral resolution and 5.8-μm axial resolution, demonstrating a great potential as an intraoperative SMA tool that can be used by surgeons and pathologists to detect residual tumors at surgical margins. It is experimentally validated that HiLo enables rapid diagnosis of different subtypes of human lung adenocarcinoma and hepatocellular carcinoma, producing images with remarkably recognizable cellular features comparable to the gold-standard histology. This work will facilitate the clinical translations of HiLo microscopy to improve the current standard-of-care.

Objectives To review and compare pregnancy outcomes of patients undergoing history-indicated, ultrasound-indicated, or rescue cerclage. Design Case series with internal comparison. Setting A regional obstetric unit in Hong Kong. Patients Women undergoing cervical cerclage at Kwong Wah Hospital between 1 January 2001 and 31 December 2011. Interventions Cervical cerclage. Main outcome measures Pregnancy outcomes including miscarriage, gestational age at delivery, birth weight, and duration of pregnancy prolongation. Results Overall, 47 patients were included. Nine (19.1%) pregnancies resulted in miscarriage. The median gestational age at delivery was 35.7 weeks. Among the 23 patients who had history-indicated cerclage, only four (17.4%) had three or more previous second-trimester miscarriages or preterm deliveries. Among the 15 patients who had ultrasound-indicated cerclage, preoperative cervical length of ≤1.5 cm was associated with shorter prolongation of pregnancy, compared with that of >1.5 cm (median, 12.1 vs 18.4 weeks; P=0.009). Among the nine women who had rescue cerclage, those who underwent the procedure before 20 weeks of gestation delivered earlier than those underwent cerclage later (median, 22.5 vs 34.1 weeks; P=0.048). Conclusions Patients eligible for the Royal College of Obstetricians and Gynaecologists-recommended history-indicated cerclage remain few. The majority of patients may benefit from serial ultrasound monitoring of cervical length with or without ultrasound-indicated cerclage.

OBJECTIVES To evaluate the efficacy and safety of double balloon catheter for induction of labour in Chinese women with one previous caesarean section and unfavourable cervix at term. DESIGN Retrospective cohort study. SETTING A regional hospital in Hong Kong. PATIENTS Women with previous caesarean delivery requiring induction of labour at term and with an unfavourable cervix from May 2013 to April 2014. MAJOR OUTCOME MEASURES Primary outcome was to assess rate of successful vaginal delivery (spontaneous or instrument-assisted) using double balloon catheter. Secondary outcomes were double balloon catheter induction-to-delivery and removal-to-delivery interval; cervical score improvement; oxytocin augmentation; maternal or fetal complications during cervical ripening, intrapartum and postpartum period; and risk factors associated with unsuccessful induction. RESULTS All 24 Chinese women tolerated double balloon catheter well. After double balloon catheter expulsion or removal, the cervix successfully ripened in 18 (75%) cases. The improvement in Bishop score 3 (interquartile range, 2-4) was statistically significant (P

This article reports the feasibility study of miniaturizing probe-fed microstrip patch antennas by dielectric loading. The loading materials are barium tetratitanate ceramics of very high dielectric constant (er = 38, 80). It is shown that, simply through loading, the antenna sizes are greatly reduced; however, the antenna performances are deteriorated. For instance, the antenna gain becomes lower. Then enhancement of the antenna performances follows. A substrate–superstrate structure is used to recover the gain. Both the experiments and the finite-difference time-domain (FDTD) simulations demonstrate that the gain and impedance bandwidth can be retrieved such that they are comparable to those of conventional microstrip antennas loaded with low permittivity materials (er < 3). © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.

The use of very high permittivity ceramic materials (er = 38, 80) to miniaturize an aperture-coupled microstrip patch antenna is reported in this article. A loss of the antenna gain in such a technique is observed, and then a novel substrate-superstrate structure is developed to enhance the gain. The whole process of gain enhancement is analyzed by using the finite-difference time-domain (FDTD) method. The simulations are excellently correlated with the experiments. They validate that the loss of the antenna gain can be recovered up to that of conventional microstrip antennas loaded with low permittivity materials (er < 3). In addition, the performance comparison of the aperture-coupled microstrip antenna of very high permittivity with the probe-fed microstrip antenna of very high permittivity is presented. It is shown that the aperture-coupled antenna has wider impedance and radiation bandwidths than the probe-fed one while keeping the antenna gain at about the same level. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 154–160, 2003.

[1] With reference to a conventional air planar inverted-F antenna this paper describes the miniaturization of the planar inverted-F antenna by dielectric loading of barium tetratitanate ceramics of very high permittivity (er = 38, 80) at 1.8 GHz. It is found that a simple loading method can reduce the antenna size but at the cost of the antenna performance. For instance, the antenna gain becomes lower. Then a sophisticated loading approach based on a novel substrate-superstrate structure is developed to improve the antenna gain. The whole process of the gain enhancement is analyzed by using the finite difference time domain method. The simulations are excellently correlated with the experiments. They both show that the sophisticated loading technique can reduce the antenna size by four times and still maintains the comparable performance.