PVA-gel beads enhance granule formation in a UASB reactor.

PVA-gel beads were used as a biocarrier in a lab-scale UASB reactor treating synthetic wastewater composed of corn steep liquor (CSL) with the aim of evaluating its use as a growth nucleus to enhance granule formation. Over 117 days of operation, the organic loading rate was increased to 22.5kgCOD/m3/day with an influent COD of about 10.8g/L at an HRT of 12h with COD removal efficiencies greater than 87%. By the end of the study period, the PVA-gel turned black and granule formation was achieved as compared with the formation of much fewer natural granules without the PVA-gel nucleus. No filamentous bacteria were found on the surface or interior of the PVA-gel beads. The PVA-gel granules had an average settling velocity 200m/h (5cm/s), and a biomass attachment of 0.93g VSS/g PVA-gel. The required time for formation of PVA-gel granules was thus demonstrated to be shorter than that of ordinary sludge granules under the experimental conditions used in this study.

Efficacy of ESP Monitoring during Thoraco-Abdominal Aortic Replacement for Prevention of Intraoperative Spinal Ischemia / 日本心臓血管外科学会雑誌

We evaluated the efficacy of evoked spinal potential (ESP) monitoring during thoracoabdominal aortic replacement to prevent intra-operative spinal ischemia. Nine patients underwent intraoperative ESP monitoring. The ESP was unchanged in 5 patients and decreased in 4 patients. However, ESP recovered in 2 of them by the following techniques: (1) perfusion of intercostal arteries, (2) elevation of distal bypass perfusion pressure, (3) slight hypothermia. Postoperative paraplegia occurred only 1 patient of the 2 whose ESP was not restored. The sensitivity and specificity of the efficacy of ESP monitoring were 100% and 87.5%, respectively. We concluded that ESP is the most useful monitoring for prevention of operative spinal ischemia during thoracoabdominal aortic replacement.