Fetoscopy-guided bipolar cord coagulation in selective fetal reduction with complicated monochorionic diamniotic twins: a prospective cohort study.

OBJECTIVE: To assess the feasibility of fetoscopy-guided bipolar umbilical cord coagulation for selective fetal reduction in complicated monochorionic diamniotic (MCDA) twin pregnancies. METHODS: MCDA twins undergoing fetoscopy-guided bipolar cord coagulation (BCC) were enrolled prospectively between December 2015 to March 2020 in a fetal medicine center. RESULTS: Twenty-three cases undergoing fetoscopy-guided BCC were finally analyzed, including 11 cases for type 2 selective intrauterine growth restriction, 4 cases for twin-twin transfusion syndrome, and 8 cases for a severe discordant anomaly. The overall survival rate was 78.3% (18/23). CONCLUSIONS: Fetoscopy-guided BCC is effective for selective fetal reduction in complicated monochorionic twin pregnancies.

Stable copper-zeolite filter media for bacteria removal in stormwater.

Cu(2+)-exchanged zeolite (ZCu) as antibacterial media shows great potential for bacteria removal from stormwater, but its stability in high salinity water needs attention. In this study, stable antibacterial media were developed by modifying ZCu through calcination and in situ Cu(OH)2 coating. Their stability and Escherichia coli removal efficiency along with impact of salinity were examined in gravity-fed columns. While copper leaching from ZCu was 20mg/L in test water of salinity 250µS/cm, it was reduced by over 97% through Cu(OH)2 coating and/or calcination. ZCu coated with Cu(OH)2 followed by heat treatment at 180°C (ZCuCuO180) exhibited more consistent E. coli removal (1.7-2.7 log) than ZCu (1.2-3.3 log) in test water of varied salinity but constant contact time 22min. ZCu calcined at 400°C (ZCu400) effectively inactivated removed bacteria during 24h drying period. In the presence of native microbial communities, new sand filters, particularly those having ZCu400 at the top to inactivate bacteria during drying periods and ZCuCuO180 midway to capture and inactivate microbes during wet events, provided the best bacterial removal (1.7 log, contact time 9min). Copper leaching from this design was 9µg/L, well below long-term irrigation standard of 200µg/L.

Removal of E. coli from urban stormwater using antimicrobial-modified filter media.

Stormwater filters featuring traditional sand filter media cannot reliably treat indicator bacteria for stormwater harvesting. In this work, copper-modified zeolite and granular activated carbon (GAC) were prepared through Cu(2+) impregnation and in situ Cu(OH)2 precipitation. Their antibacterial properties and stability in natural stormwater were studied in gravity-fed columns for 24 weeks, under typical stormwater operational conditions. 11 types of other filter media, prepared using zinc, iron, titanium and quaternary ammonium salts as antibacterial agents, were tested in parallel by way of comparison. Cu(2+)-immobilised zeolite and Cu(OH)2-coated GAC yielded an estimated 2-log reduction of E. coli within 40 min with the presence of other native microbial communities in natural stormwater. Even at high flow velocity (effective contact time of 4.5 min), both media demonstrated 0.8 log removal. Both media and Cu(2+)-treated GAC showed effective inactivation of the removed E. coli during dry periods. Copper leaching from Cu(OH)2-coated GAC was found to be below the NHMRC specified drinking water standard, while that from Cu(2+)-immobilised zeolite varied with the salinity in stormwater. These findings could provide useful information for further development of passive stormwater harvesting systems.