Publications by authors named "Akihiro Nagano"

Article Synopsis
  • The study examined the effectiveness of a down-flow hanging sponge (DHS) reactor integrated with a sedimentation tank for wastewater treatment over 500 days with various hydraulic retention times (HRT).
  • Despite the shortest HRT of 0.3 hours leading to nitrogen concentrations that affected nitrification, the effluent's BOD remained stable at around 4.0 mg·L, and all discharge standards were met during the experiment.
  • The research found that the population of comammox bacteria in the sponge biomass (5.58 to 13.2 × 10 copies·mL) suggested that these sponges create a suitable environment for their growth, potentially enhancing nitrification in the process.
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Conventional activated sludge (AS) systems are widely used to treat domestic sewage worldwide. However, the removal of nitrogen in the AS system is limited, and its concentration in the effluent exceeds the recommended values in the discharge standards. In this study, a pilot experiment was conducted to improve nitrogen removal during municipal sewage treatment by operating AS and anaerobic-aerobic (AO) systems under low dissolved oxygen (DO) conditions of less than 0.

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In this study, a two-stage down-flow hanging sponge (TSDHS) reactor was used as biotrickling filter for biogas desulfurization by utilizing the anaerobic digester supernatant (ADS) of sewage sludge of an activated sludge process (ASP). The reactor comprises a closed-type first-stage down-flow hanging sponge (1st DHS) and an open-type second-stage down-flow hanging sponge (2nd DHS) reactors. In the 1st DHS, hydrogen sulfide in biogas was dissolved into the ADS, and then it was oxidized into elemental sulfur and sulfate by microbe using dissolved oxygen and nitrite in the ADS.

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We have previously reported a novel homozygous 4-bp deletion in DDHD1 as the responsible variant for spastic paraplegia type 28 (SPG28; OMIM#609340). The variant causes a frameshift, resulting in a functionally null allele in the patient. DDHD1 encodes phospholipase A1 (PLA1) catalyzing phosphatidylinositol to lysophosphatidylinositol (LPI).

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A novel gas-scrubbing bioreactor based on a downflow hanging sponge (DHS) reactor was developed as a new volatile organic compound (VOC) treatment system. In this study, the effects of varying the space velocity and gas/liquid ratio were investigated to assess the effectiveness of using toluene gas as a model VOC. Under optimal conditions, the toluene removal rate was greater than 80%, and the maximum elimination capacity was observed at approximately 13 g-C m h.

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Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to impair bone healing. We previously reported that in colon cancer cells, celecoxib, a COX-2-selective NSAID, inhibited the canonical Wnt/β-catenin signaling pathway. Since this pathway also plays an important role in osteoblast growth and differentiation, we examined the effect of celecoxib on maturation of osteoblast-like cell line MC3T3-E1.

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Performance of a wastewater treatment system utilizing a sulfur-redox reaction of microbes was investigated using a pilot-scale reactor that was fed with actual sewage. The system consisted of an up-flow anaerobic sludge blanket (UASB) reactor and a down-flow hanging sponge (DHS) reactor with a recirculation line. Consequently, the total CODCr (465±147 mg L(-1); total BOD of 207±68 mg L(-1)) at the influent was reduced (70±14 mg L(-1); total BOD of 9±2 mg L(-1)) at the DHS effluent under the conditions of an overall hydraulic retention time of 12 h, a recirculation ratio of 2, and a low-sewage temperature of 7.

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A feasibility test of a 17 m3-pilot-scale sewage treatment system was carried out by continuous feeding of raw municipal sewage under ambient temperature conditions. The system consisted of a UASB and an aerated fixed bed reactor. Some of the effluent from the fixed bed reactor was returned to the UASB influent in order to provide a sulfate source.

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