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Despite its numerous advantages, the aerobic granular sludge (AGS) process faces several challenges that hinder its widespread implementation. One such challenge is the requirement for high organic load ratios (OLR), which significantly impacts AGS formation and stability, posing a barrier to commercialization. In response to these challenges, this study investigates the granulation and treatment efficacy of the AGS process for treating high-concentration wastewater under various OLR and settling time. Three sequential batch reactors (R1, R2, R3) were operated at OLRs of 0.167, 0.33, and 1 kg COD/m3·day. The study focuses on analyzing key parameters including sludge characteristics, extracellular polymeric substances (EPS) content, PN/PS ratio, and microbial clusters. Results demonstrate that reducing settling time from 90 to 30 min enhances sludge settleability, resulting in a maximum 50.8 % decrease in SVI30 (from 98.1 to 122.8 mL/g to 51.9-81.3 mL/g), thereby facilitating the selection of beneficial microorganisms during granulation. Particularly, at R2, the PN/PS ratio was 4.3, and EPS content increased by 1.52-fold, leading to a 1.41-fold increase in sludge attachment. This observation suggests a progressive maturation of AGS. Additionally, analysis of microbial diversity and cluster composition highlights the influence of OLR variations on the ratios of Proteobacteria and Bacteroidetes. These findings emphasize the significant impact of SBR operational strategies on AGS process performance and biological stability, offering valuable insights for the efficient operation of future high-concentration wastewater treatment processes.
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Aerobic granular sludge (AGS) represents an aggregate of sludge formed through the self-immobilization of microorganisms under aerobic conditions. It is currently under scrutiny for its potential as a technology to reduce carbon emissions and promote sustainability. The practicality of AGS stems from its ability to encourage granule formation and enhance structural stability. In this study, a total of five cations (K+, Ca2+, Mg2+, Al3+, Fe3+) were introduced to facilitate stable structuring and the formation of granules for treating high-strength wastewater, such as side-stream treatment. As a result of the experiment, the loosely bound extracellular polymeric substances (LB-EPS) content in the cation-enhanced sludge witnessed a significant increase, leading to elevated total EPS content under all experimental conditions. Furthermore, the protein (PN)/polysaccharide (PS) ratio, a pivotal component of EPS influencing AGS's hydrophobicity and structural stability, exhibited a collective increase, with Mg2+ reaching the highest value of 1.7. The relationship between relative hydrophobicity and the PN/PS ratio was found to strongly impact sludge adhesion, with noteworthy results observed particularly for Mg2+, Al3+, and Fe3+. The viability of attached cells reached 96.8 %, the highest recorded in the case of Mg2+. In the context of treating high-strength wastewater, Mg2+ emerged as the optimal cation for accelerating AGS formation and enhancing structural stability.
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OBJECTIVE: To report the experiences of triplet pregnancies complicated by twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser coagulation at a single center. METHODS: Herein, we conducted a retrospective analysis to investigate the management and perinatal outcomes of triplet pregnancies with TTTS treated at a single institution between 2017 and 2022. RESULTS: Seven of the 98 triplet pregnancies (7.1%) encountered were complicated by TTTS, and all were dichorionic triamniotic triplets. Of the seven triplet pregnancies complicated by TTTS, four were treated with fetoscopic laser coagulation at our center, at a median gestational age of 20 weeks. No procedure-related complications or maternal complications were observed. The survival rate was higher and perinatal outcomes were better in fetoscopic laser coagulation cases than in other management cases. Four donor and four recipient triplets survived, with a median gestational age of 33 weeks at delivery. Although there were no cases of poor neonatal outcomes, one case was diagnosed with white matter injury, suspected to be hypoxic-ischemic encephalopathy on postnatal investigation. CONCLUSION: Fetoscopic laser coagulation is a feasible treatment option for triplet TTTS, provided the attending specialists have extensive experience with this technique.
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In this study, the rheological properties of several commercial rice noodle strands were investigated. In the bending test, failure stress decreased as the cooking temperature increased from 80 to 90 °C, and the cooking time increased from 3 to 4 min for higher rice content noodles (>60%). The stress-relaxation test and sensory tests were carried out with bundles of noodles to investigate correlations with the bending test. The modulus of elasticity was higher at 80 than 90 °C. However, no correlation was found between cooking temperature and the rheological properties of lower rice content noodles. In the stress relaxation test, the deviation was larger due to the empty space in the bundle. In the correlation analysis, sensory stickiness was correlated with a modulus of elasticity in the bending test. Comparing the bending and stress-relaxation tests, each instrumental variable showed differences in the rheological properties of rice noodles in strands and bundles. However, the bending test measured with noodle strands seemed to be most suitable as a method of measuring the rheological properties of rice noodles.
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INTRODUCTION: Brain-derived neurotrophic factor (BDNF) is not only involved in the development, differentiation, and survival of dopaminergic neurons; it also regulates fast neurotransmission and neuronal activity. METHODS: In this study, 22 patients with acute schizophrenia and 22 age-matched healthy volunteers were recruited, and BDNF serum concentrations were measured in unmedicated patients and after 2 weeks and 4 weeks of medication. RESULTS: Brain-derived neurotrophic factor serum levels of unmedicated schizophrenic patients (n = 22; 4.38 ± 2.1 ng/mL) were significantly decreased compared to the age-matched healthy volunteers (n = 44, df = 42, P = 0.029). In a mixed-model repeated-measures analysis of variance, a significant BDNF increase has been found during treatment (χ² = 2.91; df = 1; P < 0.0001). The percental change of BDNF (increase, 173% ± 110) correlated negatively with the percental change of PANSS score (decrease: 75% ± 22; n = 18; r = -0.554; P = 0.032). CONCLUSIONS: Our study replicates studies showing that unmedicated patients with schizophrenia have decreased serum BDNF levels compared with healthy controls. Brain-derived neurotrophic factor increase during treatment seems to parallel positive and negative symptom improvement.